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Proceedings, Volume 2, Eurosensors 2018

EUROSENSORS 2018

Graz, Austria | 9–12 September 2018

Issue Editors: Anton Köck, Marco Deluca


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Cover Story (view full-size image) Proceedings, Volume 2, collects papers presented at EUROSENSORS 2018, the 32nd edition of the [...] Read more.
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Open AccessProceedings Enhancing the Performance of Commercial Infrared Detectors by Surface Plasmons
Proceedings 2018, 2(13), 63; https://doi.org/10.3390/proceedings2130063
Published: 16 November 2018
Viewed by 130 | PDF Full-text (412 KB)
Abstract
The feasibility to improve the response of quantum type (photonic) infrared (IR) detectors by applying surface plasmons is investigated. The HgCdTe material system is used as the detector platform of interest for which selected plasmonic structures and materials are applied and the influence
[...] Read more.
The feasibility to improve the response of quantum type (photonic) infrared (IR) detectors by applying surface plasmons is investigated. The HgCdTe material system is used as the detector platform of interest for which selected plasmonic structures and materials are applied and the influence studied by full-fielded electromagnetic simulations. It is shown that even for the several-micrometers-thick detector structures, similar to the commercial ones, broadband absorption enhancements of 30–40% can be achieved. The results suggest that improved, or new, pixel-level functionalities can be created for commercial IR detectors by relatively simple means. Additionally, high potential for cost reduction in high-performance IR imaging systems with multicolour capabilities is foreseen. Full article
Open AccessProceedings A Two-stage Energy Extraction Circuit for Energy Harvesting in Non-Sinusoidal Excited Environments
Proceedings 2018, 2(13), 700; https://doi.org/10.3390/proceedings2130700
Published: 3 December 2018
Viewed by 83 | PDF Full-text (730 KB)
Abstract
We present a two-stage energy extraction circuit for a piezoelectric energy harvester, powering an asset-tracking system. Exploiting non-sinusoidal accelerations generated by many logistic transport devices, e.g., pushcarts, forklifts, assembly belts or cars, we are able to harvest sufficient electrical energy to transmit radio
[...] Read more.
We present a two-stage energy extraction circuit for a piezoelectric energy harvester, powering an asset-tracking system. Exploiting non-sinusoidal accelerations generated by many logistic transport devices, e.g., pushcarts, forklifts, assembly belts or cars, we are able to harvest sufficient electrical energy to transmit radio signals, which will allow to track the object when it is moving. By using the proposed energy extraction circuit, the energy extraction efficiency could be improved by at least 30% compared to a single-stage solution for sinusoidal excitations. In the practical use-case, the two-stage energy extraction network performs more than four times better compared to the single staged on. Full article
Open AccessProceedings SPM—SEM Investigations of Semiconductor Nanowires for Integrated Metal Oxide Gas Sensors
Proceedings 2018, 2(13), 701; https://doi.org/10.3390/proceedings2130701
Published: 4 December 2018
Viewed by 87 | PDF Full-text (404 KB)
Abstract
Integration of metal oxide nanowires in metal oxide gas sensors enables a new generation of gas sensor devices, with increased sensitivity and selectivity. For reproducible and stable performance of next generation sensors, the electric properties of integrated nanowires have to be well understood,
[...] Read more.
Integration of metal oxide nanowires in metal oxide gas sensors enables a new generation of gas sensor devices, with increased sensitivity and selectivity. For reproducible and stable performance of next generation sensors, the electric properties of integrated nanowires have to be well understood, since the detection principle of metal oxide gas sensors is based on the change in electrical conductivity during gas exposure. We study two different types of nanowires that show promising properties for gas sensor applications with a Scanning Probe Microscope—Scanning Electron Microscope combination. Electron Beam Induced Current and Kelvin Probe Force Microscopy measurements with a lateral resolution in the nanometer regime are performed. Our work offers new insights into the dependence of the nanowire work function on its composition and size, and into the local interaction between electron beam and semiconductor nanowires. Full article
Open AccessProceedings Analysis of Synthesis Mechanism of Gold Nanoparticles Using Glass Microfluidics
Proceedings 2018, 2(13), 702; https://doi.org/10.3390/proceedings2130702
Published: 3 December 2018
Viewed by 97 | PDF Full-text (599 KB)
Abstract
According to LaMer diagram, a clearly separate of nucleation and grows step is required to synthesis of monodisperse nanoparticles. However, a critical mixing time Tc until the growth process is started, is not clear experimentally. In this paper, we prepared gold nanoparticles
[...] Read more.
According to LaMer diagram, a clearly separate of nucleation and grows step is required to synthesis of monodisperse nanoparticles. However, a critical mixing time Tc until the growth process is started, is not clear experimentally. In this paper, we prepared gold nanoparticles (GNPs) by liquid-phase reduction using citric acid on microfluidics with different flow rates. From relationship of the diameter of the prepared nanoparticle and the mixing time, Tc for the preparation of monodisperse GNPs was found for the first time. Full article
Open AccessProceedings The Realization of Redistribution Layers for FOWLP by Inkjet Printing
Proceedings 2018, 2(13), 703; https://doi.org/10.3390/proceedings2130703 (registering DOI)
Published: 13 December 2018
PDF Full-text (589 KB)
Abstract
The implementation of additive manufacturing technology (e.g., digital printing) to the electronic packaging segment has recently received increasing attention. In almost all types of Fan-out wafer level packaging (FOWLP), redistribution layers (RDLs) are formed by a combination of photolithography, sputtering and plating process.
[...] Read more.
The implementation of additive manufacturing technology (e.g., digital printing) to the electronic packaging segment has recently received increasing attention. In almost all types of Fan-out wafer level packaging (FOWLP), redistribution layers (RDLs) are formed by a combination of photolithography, sputtering and plating process. Alternatively, in this study, inkjet-printed RDLs were introduced for FOWLP. In contrast to a subtractive method (e.g., photolithography), additive manufacturing techniques allow depositing the material only where it is desired. In the current study, RDL structures for different embedded modules were realized by inkjet printing and further characterized by electrical examinations. It was proposed that a digital printing process can be a more efficient and lower-cost solution especially for rapid prototyping of RDLs, since several production steps will be skipped, less material will be wasted and the supply chain will be shortened. Full article
Open AccessProceedings Development of Thin Shear Force Sensor Aimed at Improving QOL for Persons with Disabilities
Proceedings 2018, 2(13), 704; https://doi.org/10.3390/proceedings2130704 (registering DOI)
Published: 14 December 2018
PDF Full-text (723 KB)
Abstract
We have been developing a sheet type shear force sensor. It has a unique structure consisting of two flexible electrode films, a rubber ring, and a liquid electrolyte. One of the electrode films has a central electrode and the other film had four
[...] Read more.
We have been developing a sheet type shear force sensor. It has a unique structure consisting of two flexible electrode films, a rubber ring, and a liquid electrolyte. One of the electrode films has a central electrode and the other film had four symmetrically arranged electrodes. The diameter of the sensor head was 10 mm and the thickness was about 0.7 mm. We also developed mobile measurement circuit and software for the computer. This system can handle up to four sensors simultaneously. Furthermore, we obtained experimental data by attaching the sensor to a human body using a double‐sided adhering tape. Full article
Open AccessProceedings A Printed Capacitance Sensor for Soil Moisture Measurement
Proceedings 2018, 2(13), 705; https://doi.org/10.3390/proceedings2130705
Published: 3 December 2018
Viewed by 102 | PDF Full-text (837 KB)
Abstract
The introduction and evaluation of a novel sensor design for a soil moisture sensor that can be manufactured on a PCB. The PCB acts as a capacitor, which uses the fringe effect to allow changes in permittivity of its surrounding medium to be
[...] Read more.
The introduction and evaluation of a novel sensor design for a soil moisture sensor that can be manufactured on a PCB. The PCB acts as a capacitor, which uses the fringe effect to allow changes in permittivity of its surrounding medium to be identified, and this capacitance is measured via relatively simple charge and discharge times between two voltages through a series resistor. The system is implemented in a low-cost microcontroller, and coupled with being printable on a PCB, has the potential to make a highly cost-effective sensor. A custom Android Bluetooth application was produced to provide communication with and configuration of the sensor. Full article
Open AccessProceedings Photostimulable Phosphor Glass for Ionizing Radiation Monitoring
Proceedings 2018, 2(13), 706; https://doi.org/10.3390/proceedings2130706
Published: 12 December 2018
PDF Full-text (929 KB)
Abstract
Silver (Ag+) doped phosphate glass after exposure to ionizing radiation has an intense luminescence by stimulating with ultra-violet light. This phenomenon is called radiophotoluminescence (RPL). The RPL intensity was increased linearly with increasing X-ray irradiation dose up to about 1000 Gy. Small amount
[...] Read more.
Silver (Ag+) doped phosphate glass after exposure to ionizing radiation has an intense luminescence by stimulating with ultra-violet light. This phenomenon is called radiophotoluminescence (RPL). The RPL intensity was increased linearly with increasing X-ray irradiation dose up to about 1000 Gy. Small amount of bead-type RPL glass as large as about 0.05mm was well prepared with a jet flame system. It was confirmed that the RPL glass beads could be used as passive-type radiation dosimeters. Visualization and monitoring system of radiation dose distribution utilizing RPL phenomenon in the Ag+-doped phosphate glass are developed in this study. In the presentation, the basic luminescence properties are reported as well as the application of Ag+-doped phosphate glass beads to radiation dose distribution monitoring. Full article
Open AccessProceedings Low Cost Micro Milling Machine for Prototyping Plastic Microfluidic Devices
Proceedings 2018, 2(13), 707; https://doi.org/10.3390/proceedings2130707
Published: 4 December 2018
Viewed by 93 | PDF Full-text (595 KB)
Abstract
Micro-milling is one of the commonly used methods of fabrication of microfluidic devices necessary for cell biological research and application. Commercial micro-milling machines are expensive, and researchers in developing countries can’t afford them. Here, we report the design and the development of a
[...] Read more.
Micro-milling is one of the commonly used methods of fabrication of microfluidic devices necessary for cell biological research and application. Commercial micro-milling machines are expensive, and researchers in developing countries can’t afford them. Here, we report the design and the development of a low-cost (<130 USD) micro milling machine and asses the prototyping capabilities of microfeatures in plastic materials. We demonstrate that the developed machine can be used in fabricating the plastic based microfluidic device. Full article
Open AccessProceedings Ruthenium Oxide pH Sensing for Organs-On-Chip Studies
Proceedings 2018, 2(13), 709; https://doi.org/10.3390/proceedings2130709
Published: 5 December 2018
Viewed by 101 | PDF Full-text (685 KB)
Abstract
A ruthenium oxide (RuOx) electrode is being developed as potentiometric pH sensor for organs-on-chip applications. Open-circuit potential (OCP) of the RuOx electrode showed a response of −58.05 mV/pH, with no cross-sensitivity to potentially interfering/complexing ions (tested were lithium, sulfate, chloride, and calcium ions).
[...] Read more.
A ruthenium oxide (RuOx) electrode is being developed as potentiometric pH sensor for organs-on-chip applications. Open-circuit potential (OCP) of the RuOx electrode showed a response of −58.05 mV/pH, with no cross-sensitivity to potentially interfering/complexing ions (tested were lithium, sulfate, chloride, and calcium ions). Similar response was observed in complex biological medium. The electrode stored in liquid had a long-term drift of −0.8 mV/hour (corresponding to ΔpH of 0.013/hour) and response time in complex biological medium was 3.7 s. Minimum cross-sensitivity to oxygen was observed as the OCP shifted ~3 mV going from deoxygenated to oxygenated solution. This response is one magnitude lower than previously reported for metal- oxide pH sensors. Overall, the RuOx pH sensor has proven to be a suitable pH sensor for organs- on-chip applications. Full article
Open AccessProceedings In-Plane Sensitive Magnetoresistors as a Hall Device
Proceedings 2018, 2(13), 710; https://doi.org/10.3390/proceedings2130710
Published: 5 December 2018
Viewed by 91 | PDF Full-text (276 KB)
Abstract
A novel coupling of a pair of identical two-contact (2C) magnetoresistors transformed into an in-plane sensitive Hall device is presented. The ohmic contacts are cross-linked, also adding a load resistor bridge, providing for constant current mode of operation and eliminating the inevitable parasitic
[...] Read more.
A novel coupling of a pair of identical two-contact (2C) magnetoresistors transformed into an in-plane sensitive Hall device is presented. The ohmic contacts are cross-linked, also adding a load resistor bridge, providing for constant current mode of operation and eliminating the inevitable parasitic offset. This silicon configuration, apart from its simplified layout, has linear and odd output voltage as a function of the magnetic field and current. The quadratic and even magnetoresistance in the two parts of this innovative device is completely compensated, which ensures high measurement accuracy alongside with identification of the magnetic field polarity. The experimental prototypes feature sensitivity of 110 V/AT. The mean lowest detected magnetic induction B at supply current of 3 mA over frequency range f ≤ 100 Hz at a signal-to-noise ratio equal to unity is Bmin ≈ 10 μT. Тhe high performance and the complete electrical, temperature and technological matching of the parts of this unusual Hall device make it very promising for many practical applications. Full article
Open AccessProceedings 2D In-Plane Sensitive Hall-Effect Sensor
Proceedings 2018, 2(13), 711; https://doi.org/10.3390/proceedings2130711
Published: 30 November 2018
Viewed by 74 | PDF Full-text (313 KB)
Abstract
A new 2D (two-dimensional) in-plane sensitive Hall-effect sensor comprising two identical n-Si Greek-crosses is presented. Each of the crosses contains one central square contact and, symmetrically to each of their four sides, an outer contact is available. Outer electrode from one configuration
[...] Read more.
A new 2D (two-dimensional) in-plane sensitive Hall-effect sensor comprising two identical n-Si Greek-crosses is presented. Each of the crosses contains one central square contact and, symmetrically to each of their four sides, an outer contact is available. Outer electrode from one configuration is connected with the respective opposite contact from the other configuration, thus forming four parallel three-contact (3C) Hall elements. These original connections provide pairs of opposite supply currents in each of the cross-Hall structure. Also the obligatory load resistors in the outer contacts of 3С Hall elements are replaced by internal resistances of crosses themselves. The samples have been implemented by IC technology, using four masks. The magnetic field is parallel to the structures’ plane. The couples of opposite contacts of each Greek-cross are the outputs for the two orthogonal components of the magnetic vector at sensitivities S ≈ 115 V/AT whereas the cross-talk is very promising, reaching no more than 2.4%. The mean lowest detected magnetic induction B at a supply current Is = 3 mA over the frequency range f ≤ 500 Hz at a signal to noise ratio equal to unity, is Bmin ≈ 14 μT. Full article
Open AccessProceedings Equivalent Circuit Model of an Optomechanical MEMS Electric Field Strength Sensor
Proceedings 2018, 2(13), 712; https://doi.org/10.3390/proceedings2130712
Published: 3 December 2018
Viewed by 123 | PDF Full-text (1469 KB)
Abstract
We present a simple equivalent circuit model for the transfer function of an optomechanical MEMS transducer capable of distortion-free electric field strength measurements. This model allows not only to qualitatively understand the characteristics of the transducer but also takes into account parasitic effects
[...] Read more.
We present a simple equivalent circuit model for the transfer function of an optomechanical MEMS transducer capable of distortion-free electric field strength measurements. This model allows not only to qualitatively understand the characteristics of the transducer but also takes into account parasitic effects and material properties. Such parasitic effects have been observed while evaluating the first results of electric field measurements performed with the sensor. The model helped to identify and diminish these parasitic effects. Full article
Open AccessProceedings Detection of Heart and Respiration Rate with an Organic-Semiconductor-Based Optomechanical MEMS Sensor
Proceedings 2018, 2(13), 715; https://doi.org/10.3390/proceedings2130715
Published: 10 December 2018
PDF Full-text (3891 KB)
Abstract
We present a displacement-sensitive sensor comprising a microelectromechanical (MEMS) chip and organic optoelectronic components capable of measuring the heart and respiration rate on humans. The MEMS sensor relies on the inertial deflection of a small silicon oscillator. The readout of the deflection is
[...] Read more.
We present a displacement-sensitive sensor comprising a microelectromechanical (MEMS) chip and organic optoelectronic components capable of measuring the heart and respiration rate on humans. The MEMS sensor relies on the inertial deflection of a small silicon oscillator. The readout of the deflection is optical and works via modulation of the light flux passing through the MEMS. Organic optoelectronics are used as light source and detector, since these offer a homogeneous light distribution and a more compact package in a future integration. Two types of MEMS, differing in their resonance frequency, were designed and characterised in combination with both organic and inorganic optoelectronics prior to measuring heart and respiration rate. Subsequently, by measurements on the neck, pulse and respiration rate were successfully measured. Full article
Open AccessProceedings Polyethylene Outgassing Study for MEMS Nuclear Radiation Sensor
Proceedings 2018, 2(13), 718; https://doi.org/10.3390/proceedings2130718
Published: 30 November 2018
Viewed by 105 | PDF Full-text (632 KB)
Abstract
In this paper, the out-gassing from PolyEthylene (PE) film is studied under nuclear irradiation for the design and fabrication of passive MEMS dosimeters. The fabrication of sensor needs high temperature process that leads to specific constraints on the PE film. Radiation chemical yield
[...] Read more.
In this paper, the out-gassing from PolyEthylene (PE) film is studied under nuclear irradiation for the design and fabrication of passive MEMS dosimeters. The fabrication of sensor needs high temperature process that leads to specific constraints on the PE film. Radiation chemical yield of hydrogen production (GH2) from PE under gamma irradiation is verified by mass spectroscopy after temperature annealing in vacuum up to 400 °C. Prototypes are fabricated to validate the fabrication of the sensor and then irradiated with high energy gamma radiation (with dose of 20 kGy). Measurements of membrane deflections after irradiation validate the GH2 factor, showing low pollution level of PE during sensor fabrication. Full article
Open AccessProceedings Cross-Sensitivity of an Optomechanical MEMS Transducer
Proceedings 2018, 2(13), 719; https://doi.org/10.3390/proceedings2130719
Published: 3 December 2018
Viewed by 72 | PDF Full-text (1084 KB)
Abstract
This work presents the investigation on a MEMS based optomechanical transducer for displacements or vibration regarding its cross-sensitivities to multidirectional input excitations. The principle of the optomechanical transducer is based on the modulation of the light flux passing through one static and one
[...] Read more.
This work presents the investigation on a MEMS based optomechanical transducer for displacements or vibration regarding its cross-sensitivities to multidirectional input excitations. The principle of the optomechanical transducer is based on the modulation of the light flux passing through one static and one movable micromechanical aperture. This kind of transducer is of increasing interest for MEMS sensors since it has inherent benefits and can compete with state-ofthe- art readout concepts regarding its resolution. We have experimentally proven that the sensitivities of the device is 3.3 × 107 V/m in x-direction, 8.23 × 106 V/m in y-direction, while it is negligible in z-direction. Full article
Open AccessProceedings Gasochromic Detection of NO2 on the Example of the Food Additive E141 (ii)
Proceedings 2018, 2(13), 721; https://doi.org/10.3390/proceedings2130721
Published: 4 December 2018
Viewed by 82 | PDF Full-text (635 KB)
Abstract
We present our investigation on the gasochromic reaction of E141 (ii) towards the toxic gas nitrogen dioxide (NO2). E141 (ii) is a chlorophyllin-based food additive, typically used as green coloring for nearly all kinds of sweets. In this presentation we show an alternative
[...] Read more.
We present our investigation on the gasochromic reaction of E141 (ii) towards the toxic gas nitrogen dioxide (NO2). E141 (ii) is a chlorophyllin-based food additive, typically used as green coloring for nearly all kinds of sweets. In this presentation we show an alternative approach for using E141 (ii) as optical gas indicator. All solid samples are prepared by multi-layer screen printing on different substrates like paper and PE-foil. Gas measurements are performed using an UV/Vis spectrometer. The influence of the substrate and according layer thickness is shown. Full article
Open AccessProceedings Gas Sensing Characteristics of a WO3 Thin Film Prepared by a Sol-Gel Method
Proceedings 2018, 2(13), 723; https://doi.org/10.3390/proceedings2130723
Published: 4 December 2018
Viewed by 77 | PDF Full-text (590 KB)
Abstract
Preparation and characterization of a WO3-based thin film gas sensor are reported. The WO3 film was prepared on a polished alumina substrate by a sol-gel method using an aqueous mixture solution of ammonium metatungstate hydrate and poly-vinyl alcohol, and fabricated
[...] Read more.
Preparation and characterization of a WO3-based thin film gas sensor are reported. The WO3 film was prepared on a polished alumina substrate by a sol-gel method using an aqueous mixture solution of ammonium metatungstate hydrate and poly-vinyl alcohol, and fabricated into the gas sensor by forming interdigital electrodes on the surface. The characterization was conducted by measuring the electrical resistance change in NO, H2, and NH3 ambient as a function of gas concentration. It is revealed that the sensor has a specific sensitivity to NO, NO is detected as oxidizing gas although it is expected to be reducing gas, and the resistance changes with gas concentration in accordance with the Langmuir isotherm plot. Full article
Open AccessProceedings Equivalent Circuit-Based Open-Circuit Sensitivity Modelling of a Capacitive-Type MEMS Acoustic Sensor on Wafer Level
Proceedings 2018, 2(13), 724; https://doi.org/10.3390/proceedings2130724
Published: 10 December 2018
PDF Full-text (426 KB)
Abstract
Equivalent circuit-based analytical open-circuit sensitivity modelling of a capacitive-type MEMS acoustic sensor for Internet of things (IoT) application is presented. It can not only evaluate simply the characteristic of the sensitivity on wafer level, but also improve the accuracy of the sensitivity due
[...] Read more.
Equivalent circuit-based analytical open-circuit sensitivity modelling of a capacitive-type MEMS acoustic sensor for Internet of things (IoT) application is presented. It can not only evaluate simply the characteristic of the sensitivity on wafer level, but also improve the accuracy of the sensitivity due to including the fringing field between the diaphragm and each etching hole in the back-plate. The effective capacitor model is obtained by applying the approximately linearized electric-field method (ALEM), resulting in the equivalent circuit-based dynamic model. From the sensor with a 325 µm-radius diaphragm, the effective radius and the effective residual stress of the diaphragm were extracted to be 299 µm and +23.0 MPa, respectively. With the pull-in voltage of. 12.0 V and the pad capacitance of 0.23 pF; the open-circuit sensitivity was modelled to 11.3 mV/Pa at 1 kHz in the bias of 10 V. Full article
Open AccessProceedings Highly Confined Love Waves Modes by Defects States in a Phononic Crystal Based on Holey-SiO2/ST-Cut Quartz Structure
Proceedings 2018, 2(13), 729; https://doi.org/10.3390/proceedings2130729 (registering DOI)
Published: 13 December 2018
PDF Full-text (436 KB)
Abstract
We investigate the properties of highly confined Love modes in a phononic crystal based on an array of holes made in SiO2 deposited on ST-cut Quartz substrate. An optimal choice of the geometrical parameters of the holes enables us to obtain wide
[...] Read more.
We investigate the properties of highly confined Love modes in a phononic crystal based on an array of holes made in SiO2 deposited on ST-cut Quartz substrate. An optimal choice of the geometrical parameters of the holes enables us to obtain wide stop-bands frequency for shear wave’s modes. The introduction of defect by removing lines of holes leads to nearly flat modes within the band gap and consequently paves the way to implement advanced design of electroacoustic filters and high-performance cavity resonators based on shear wave modes. The calculations are performed using finite element method based on the commercial software (COMSOL-Multiphysics). For transmission spectra, piezoelectric excitations are applied by considering the interdigital transducers, with results corroborating well the band structure predictions and the position of defects modes within the band gap. Full article
Open AccessProceedings Multilayered, Package-Less SAW Sensors: Latest Developments
Proceedings 2018, 2(13), 730; https://doi.org/10.3390/proceedings2130730
Published: 10 December 2018
PDF Full-text (604 KB)
Abstract
Passive and wireless SAW sensors can operate in extreme environment. However, there is no mass-market application for this technology yet, due notably to the lack of an adequate sensor housing solution. Package-less SAW sensors are therefore promising. Here, guided waves that propagate in
[...] Read more.
Passive and wireless SAW sensors can operate in extreme environment. However, there is no mass-market application for this technology yet, due notably to the lack of an adequate sensor housing solution. Package-less SAW sensors are therefore promising. Here, guided waves that propagate in a protective multilayer structure are used, instead of SAWs. However, issues will arise from the use of a multilayer structure. In particular, thermo-mechanical effects will impact the behavior of the devices. A solution must also be found to embed the antenna in the stack. We present here the results of a numerical study of the thermo-mechanical effects, in two package-less structures. One possible antenna design is proposed and evaluated. Full article
Open AccessProceedings A Portable & Disposable Ultra-Low Velocity Flow Sensor from Bioinspired Hair-Like Microstructures
Proceedings 2018, 2(13), 731; https://doi.org/10.3390/proceedings2130731
Published: 3 December 2018
Viewed by 91 | PDF Full-text (532 KB)
Abstract
We present, for the first time, the design, development and testing of a portable ultra-low
velocity flow sensor with a disposable architecture for use in medical applications. 3Dmicroprinting
technique was used to fabricate high aspect ratio microscopic hair-like structures
from conducting polymers, in
[...] Read more.
We present, for the first time, the design, development and testing of a portable ultra-low
velocity flow sensor with a disposable architecture for use in medical applications. 3Dmicroprinting
technique was used to fabricate high aspect ratio microscopic hair-like structures
from conducting polymers, in particular, poly(3,4-ethylenedioxythiophene):polystyrene-sulfonate
(PEDOT:PSS). These high aspect ratio micro-hairs are flexible and conductive that can respond to
air flowing over them. A disposable and portable flow sensor with a modular design that allows
tuning of measurement range was developed, for integration with an automated neonatal
resuscitator to provide closed-loop feedback. The developed portable sensor architecture is capable
of real-time indication of the air flow velocity range down to few millimeters/second. Full article
Open AccessProceedings Printing of Soft Stretch Sensor from Carbon Black Composites
Proceedings 2018, 2(13), 732; https://doi.org/10.3390/proceedings2130732
Published: 10 December 2018
PDF Full-text (339 KB)
Abstract
Demand for highly stretchable mechanical sensors for use in the fields of soft robotics and wearable sensors has been constantly rising. Carbon based materials as piezo-resistive material are low-cost and have been widely used. In this paper instead of using the controversial carbon-nanotubes,
[...] Read more.
Demand for highly stretchable mechanical sensors for use in the fields of soft robotics and wearable sensors has been constantly rising. Carbon based materials as piezo-resistive material are low-cost and have been widely used. In this paper instead of using the controversial carbon-nanotubes, carbon black nano-particles mixed with Ecoflex® as piezo-resistive nanocomposite are used and measure strain up to 100%. Two fabrication techniques incorporating the printing (namely-“layer-upon-layer” and “embedded”) of the carbon black nanocomposite will be explored and the performances of the sensors made from these techniques will be evaluated. Full article
Open AccessProceedings Prototype System for the Detection of Volatile Hydrocarbons in Water
Proceedings 2018, 2(13), 734; https://doi.org/10.3390/proceedings2130734
Published: 4 December 2018
Viewed by 85 | PDF Full-text (472 KB)
Abstract
Detection of dissolved methane and volatile hydrocarbons in water is a problem met in
leakage localization during exploitation of underwater pipelines, oil and oil product spill over water
surface, geological exploration work for the localization of oil and gas fields under water, etc.
[...] Read more.
Detection of dissolved methane and volatile hydrocarbons in water is a problem met in
leakage localization during exploitation of underwater pipelines, oil and oil product spill over water
surface, geological exploration work for the localization of oil and gas fields under water, etc. This
problem can be solved by the application of detection system based on tubular selective membrane
permeable for volatile organics and impenetrable for liquid water. Carrier gas (air) flowing through
this tube is saturated with dissolved gas and then gas concentration is measured using
semiconductor or other gas sensor. The system prototype was tested under laboratory conditions
and demonstrated low limit of gas detection (~20 ppb by mass of dissolved methane in water) and
short response time (~10 s). Full article
Open AccessProceedings Quartz Enhanced Photoacoustic Spectroscopy Based Gas Sensor with a Custom Quartz Tuning Fork
Proceedings 2018, 2(13), 735; https://doi.org/10.3390/proceedings2130735
Published: 10 December 2018
PDF Full-text (439 KB)
Abstract
We have fabricated a custom quartz tuning fork (QTF) with a reduced fundamental frequency, a larger gap between the prongs and the best quality factor in air at atmospheric conditions ever reported. Acoustic microresonators have been added to the QTF, these were optimized
[...] Read more.
We have fabricated a custom quartz tuning fork (QTF) with a reduced fundamental frequency, a larger gap between the prongs and the best quality factor in air at atmospheric conditions ever reported. Acoustic microresonators have been added to the QTF, these were optimized through experiments. We demonstrate a normalized noise equivalent absorption of 3.7 × 10−9 W·cm−1·Hz−1/2 for CO2 detection at atmospheric pressure. Influence of the inner diameter and length of the microresonators has been studied as well as the penetration depth between the QTF prongs. Full article
Open AccessProceedings Enzymatic Sensor Based on Dye Sensitized TiO2 Electrode for Detection of Catechol in Water
Proceedings 2018, 2(13), 737; https://doi.org/10.3390/proceedings2130737
Published: 4 December 2018
Viewed by 71 | PDF Full-text (1914 KB)
Open AccessProceedings Optimization of Si-Based Waveguides for Evanescent-Field Sensors
Proceedings 2018, 2(13), 739; https://doi.org/10.3390/proceedings2130739
Published: 30 November 2018
Viewed by 101 | PDF Full-text (519 KB)
Abstract
We present a detailed study of Si-based optical waveguides, which can be used as evanescent field sensors for the quantitative analysis of various gases and liquids. Direct quantitative comparison of simulation with experimental results of directional coupling structures allows fine-tuning the material parameters
[...] Read more.
We present a detailed study of Si-based optical waveguides, which can be used as evanescent field sensors for the quantitative analysis of various gases and liquids. Direct quantitative comparison of simulation with experimental results of directional coupling structures allows fine-tuning the material parameters and provides important input for future sensor design. Full article
Open AccessProceedings Tuning Material Properties of ZnO Thin Films for Advanced Sensor Applications
Proceedings 2018, 2(13), 740; https://doi.org/10.3390/proceedings2130740
Published: 3 December 2018
Viewed by 66 | PDF Full-text (534 KB)
Abstract
We report on the growth of ZnO thin films by plasma-enhanced atomic layer deposition as a function of substrate temperature. The method to ensure self-limiting growth with precise thickness control is discussed and the effect of temperature on the texture of the thin
[...] Read more.
We report on the growth of ZnO thin films by plasma-enhanced atomic layer deposition as a function of substrate temperature. The method to ensure self-limiting growth with precise thickness control is discussed and the effect of temperature on the texture of the thin films is presented. Switching the texture from (100) to (002) by increasing the substrate temperature is a key property for functional devices. The ZnO thin films with tailored properties could find applications in a wide range of sensors and actuators. Full article
Open AccessProceedings Commercially Fabricated Printed Circuit Board Sensing Electrodes for Biomarker Electrochemical Detection: The Importance of Electrode Surface Characteristics in Sensor Performance
Proceedings 2018, 2(13), 741; https://doi.org/10.3390/proceedings2130741
Published: 29 November 2018
Viewed by 95 | PDF Full-text (835 KB)
Abstract
Here we report the first PCB-implemented electrochemical glucose biosensor using
covalently immobilized glucose oxidase (GOx) on the commercially fabricated PCB electrode
surface, taking particular care on the electrode surface characteristics and their effect on sensor
performance. Based on the results, this assay exhibits
[...] Read more.
Here we report the first PCB-implemented electrochemical glucose biosensor using
covalently immobilized glucose oxidase (GOx) on the commercially fabricated PCB electrode
surface, taking particular care on the electrode surface characteristics and their effect on sensor
performance. Based on the results, this assay exhibits a highly linear response from 500 μM to 20
mM (R = 0.9961) and a lower limit of detection of 500 μM. Full article
Open AccessProceedings Reference-Electrode Free pH Sensing Using Impedance Spectroscopy
Proceedings 2018, 2(13), 742; https://doi.org/10.3390/proceedings2130742
Published: 30 November 2018
Viewed by 87 | PDF Full-text (371 KB)
Abstract
We present a reference-electrode free sensor able to measure both pH and conductivity
based on impedance spectroscopy. The electrode is made of a layer of indium-tin-oxide (ITO). The
impedance of this electrode at low frequencies depends on its double layer capacity, which varies
[...] Read more.
We present a reference-electrode free sensor able to measure both pH and conductivity
based on impedance spectroscopy. The electrode is made of a layer of indium-tin-oxide (ITO). The
impedance of this electrode at low frequencies depends on its double layer capacity, which varies
with pH due to modification of oxide groups at the ITO surface. At high frequencies, the impedance
is determined by the resistance in the system, which corresponds to the inverse conductivity of the
solution. Because no reference electrode is needed for this technique, miniaturization of the pH
sensor is simple. We demonstrate a proof-of-principle experiment of the sensor for human plasma
pH measurements. Full article
Open AccessProceedings Optimization in the Design and Fabrication of a PZT Piezoelectric Micromachined Ultrasound Transducer (PMUT)
Proceedings 2018, 2(13), 743; https://doi.org/10.3390/proceedings2130743
Published: 29 November 2018
Viewed by 96 | PDF Full-text (774 KB)
Abstract
This paper presents an optimized way of lead zirconate titanate (PZT) deposition in order
to selectively grow three different (100/001), (110), and (111) crystal orientation in two different
thickness ranges, thinner and thicker than 400 nm. The thickness of the PZT layer is
[...] Read more.
This paper presents an optimized way of lead zirconate titanate (PZT) deposition in order
to selectively grow three different (100/001), (110), and (111) crystal orientation in two different
thickness ranges, thinner and thicker than 400 nm. The thickness of the PZT layer is also optimized
to not diminish the generated bending moment more than 10%. A 1μm PZT layer with (100/001)
dominant crystal orientation and highly columnar crystal structure is deposited and used in the
fabrication of a circular PMUT. The PMUT has a 410 μm diameter and resonates at 462 kHz with
the displacement of 1200 nm/V. Full article
Open AccessProceedings Response Time of a Fiber Bragg Grating Based Hydrogen Sensor for Transformer Monitoring
Proceedings 2018, 2(13), 745; https://doi.org/10.3390/proceedings2130745
Published: 6 December 2018
Viewed by 88 | PDF Full-text (726 KB)
Abstract
We developed and optimized a new fiber optic sensor using palladium foils attached to optical fiber Bragg gratings (FBG) for hydrogen measurements. Fifteen in parallel processed sensors were characterized and qualified in two custom tailored experimental set ups and their response to a
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We developed and optimized a new fiber optic sensor using palladium foils attached to optical fiber Bragg gratings (FBG) for hydrogen measurements. Fifteen in parallel processed sensors were characterized and qualified in two custom tailored experimental set ups and their response to a 5% hydrogen/nitrogen gas mixture and the same gas bubbled trough transformer oil was measured. The hydrogen response is similar for both medium and close to the theoretical maximum sensitivity, but the response time was found to be very different, much slower in oil than in gas. A theoretical comparison of hydrogen diffusion trough palladium and hydrogen absorption on the palladium surface as well as a measurement of the hydrogen uptake and diffusion trough the oil to the sensor have been done to investigate the origin of the different response time. They indicate that the response time determining step is the absorption of hydrogen on the palladium surface and that this process is slowed down in oil compared to a pure gas environment. Full article
Open AccessProceedings Development and Characterization of Fiber-Based Pressure Sensors
Proceedings 2018, 2(13), 746; https://doi.org/10.3390/proceedings2130746
Published: 20 November 2018
Viewed by 114 | PDF Full-text (296 KB)
Abstract
The integration of strand-based pressure sensors directly into woven textiles is a promising strategy to maintain textile properties, such as the flexibility, and to functionalize fabrics. The development of capacitive sensing elements is often based on the construction of laminates, which adversely affect
[...] Read more.
The integration of strand-based pressure sensors directly into woven textiles is a promising strategy to maintain textile properties, such as the flexibility, and to functionalize fabrics. The development of capacitive sensing elements is often based on the construction of laminates, which adversely affect the flexibility and thickness of textiles. In this paper, we present two alternative approaches by manufacturing cylindrical, pressure-sensitive, variable capacitors and twisted strand-based capacitive sensors. They lead to an easy integration method, where sensors can either be embedded or used to construct the body of textiles. In the cause of these studies, SBR/gelatin has been found to be a very useful pressure sensitive insulation system for the production of low cost capacitive sensors. Full article
Open AccessProceedings Bubble Formation in Droplet Dosing Devices for Liquid Medicine
Proceedings 2018, 2(13), 747; https://doi.org/10.3390/proceedings2130747
Published: 30 November 2018
Viewed by 75 | PDF Full-text (278 KB)
Abstract
Droplet dosing devices for liquid medicine are widely spread in self-medication for prevention or in the event of illness. This paper presents investigations on the often unnoticed process of bubble formation in droplet dosing devices for liquid medicine which is decisive for the
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Droplet dosing devices for liquid medicine are widely spread in self-medication for prevention or in the event of illness. This paper presents investigations on the often unnoticed process of bubble formation in droplet dosing devices for liquid medicine which is decisive for the whole functionality of these systems. To obtain information about this process and how it affects the dosage, drip operations with an exemplary device have been evaluated. Based on these evaluations the bubble formation is explained qualitatively. Finally a mathematical approach to predict critical changes in the bubble formation process is presented. Full article
Open AccessProceedings Ultra-Thin Sensor Systems Integrating Silicon Chips with On-Foil Passive and Active Components
Proceedings 2018, 2(13), 748; https://doi.org/10.3390/proceedings2130748
Published: 3 December 2018
Viewed by 72 | PDF Full-text (626 KB)
Abstract
Hybrid System-in-Foil exploits the complementary benefits of integrating embedded silicon chips with on-foil passive and active electronic components. In this work, the design, fabrication and characterization of three on-foil components, namely a humidity sensor, near field communication antenna and organic thin-film transistors, are
[...] Read more.
Hybrid System-in-Foil exploits the complementary benefits of integrating embedded silicon chips with on-foil passive and active electronic components. In this work, the design, fabrication and characterization of three on-foil components, namely a humidity sensor, near field communication antenna and organic thin-film transistors, are investigated. Full article
Open AccessProceedings SPAD-Based LiDAR Sensor in 0.35 µm Automotive CMOS with Variable Background Light Rejection
Proceedings 2018, 2(13), 749; https://doi.org/10.3390/proceedings2130749
Published: 23 November 2018
Viewed by 119 | PDF Full-text (504 KB)
Abstract
We present a SPAD-based LiDAR sensor fabricated in an automotive certified 0.35 µm CMOS process. Since reliable sensor operation in high ambient light environment is a crucial factor in automotive applications, four SPADs are implemented in each pixel to suppress ambient light by
[...] Read more.
We present a SPAD-based LiDAR sensor fabricated in an automotive certified 0.35 µm CMOS process. Since reliable sensor operation in high ambient light environment is a crucial factor in automotive applications, four SPADs are implemented in each pixel to suppress ambient light by the detection of photon coincidences. By pixel individual adjustment of the coincidence parameters to the present ambient light condition, an almost constant measurement performance is achieved for a wide range of different target reflectance and ambient illumination levels. This technique allows the acquisition of high dynamic range scenes in a single laser shot. For measurement and demonstration purpose a LiDAR camera with the developed sensor has been built. Full article
Open AccessProceedings Microfluidic Construction of Hierarchically Composite Superballs for Sensing Applications
Proceedings 2018, 2(13), 750; https://doi.org/10.3390/proceedings2130750
Published: 30 November 2018
Viewed by 91 | PDF Full-text (2956 KB)
Abstract
Colloidal photonic crystals have attracted much attention of the scientific world due to their unique optical properties and potential applications in sensing, displays, optoelectronics, controlled superwetting and other fields. Here we report the fabrication of spherical colloidal photonic crystals featured with well-ordered nanopatterns
[...] Read more.
Colloidal photonic crystals have attracted much attention of the scientific world due to their unique optical properties and potential applications in sensing, displays, optoelectronics, controlled superwetting and other fields. Here we report the fabrication of spherical colloidal photonic crystals featured with well-ordered nanopatterns from silica nanoparticles (SiO2NPs) and gold nanoparticles (AuNPs) through a droplet-based microfluidic approach. The colloidal crystals show both the photonic band gaps (PBG) and surface plasmonic resonance (SPR) properties. These proposed hierarchically composite ‘superballs’ will have an excellent performance in sensing applications, due to the fast response (the scattering color change) to the dielectric properties of the surrounding medium. A robust and efficient strategy is proposed and demonstrated to fabricate the composite superballs with multifunctional properties, broadening the perspective of their applications by the advantages of precise control over the size of the particles and flexible change of the fluid composition. Full article
Open AccessProceedings Narrow-Band Thermal Photonic Crystal Emitter for Mid-Infrared Applications
Proceedings 2018, 2(13), 752; https://doi.org/10.3390/proceedings2130752
Published: 22 November 2018
Viewed by 115 | PDF Full-text (562 KB)
Abstract
Mid-infrared (MIR) on-chip sensing on Si has been a progressive topic of research in the recent years due to excitation of vibrational and rotational bands specific to materials in this range and their immunity against visible light and electromagnetic interferences. For on-chip applications,
[...] Read more.
Mid-infrared (MIR) on-chip sensing on Si has been a progressive topic of research in the recent years due to excitation of vibrational and rotational bands specific to materials in this range and their immunity against visible light and electromagnetic interferences. For on-chip applications, integration of all the optical components including the MIR source is crucial. In this work, we introduce a slab photonic crystal (PhC) thermal source where the birthplace and the filtering of the photons occur in the same region. Due to the forbidden frequency bands and high density of states in the band edge, it provides electric efficiency and filtering performance. Full article
Open AccessProceedings Understanding the Sensing Mechanism of Rh2O3 loaded In2O3
Proceedings 2018, 2(13), 754; https://doi.org/10.3390/proceedings2130754
Published: 6 December 2018
Viewed by 87 | PDF Full-text (573 KB)
Abstract
The effect of Rh loading on CO sensing was studied for the case of In2O3. This was done by performing measurements with sensors based on loaded and unloaded materials that were performed at an operation temperature of 300 °C
[...] Read more.
The effect of Rh loading on CO sensing was studied for the case of In2O3. This was done by performing measurements with sensors based on loaded and unloaded materials that were performed at an operation temperature of 300 °C in the presence of low background oxygen concentration according to an experimental procedure that was demonstrated to help clarify the reception/transduction functions of loaded Semiconducting Metal Oxides (SMOX). The experimental investigation methods were DC resistance and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The results indicate that in the case of Rh2O3 loaded In2O3 the reaction primary takes place on the Rh2O3 cluster and the electrical properties of the In2O3 are controlled by the pinning of the SMOX Fermi-level to the one of the Rh2O3 cluster. Full article
Open AccessProceedings Frequency Splitting in MEMS Ring-based Coriolis Vibrating Gyroscopes Caused by Support Non-Linearity
Proceedings 2018, 2(13), 755; https://doi.org/10.3390/proceedings2130755
Published: 21 November 2018
Viewed by 111 | PDF Full-text (392 KB)
Abstract
A mathematical model is developed to describe the 2? in-plane flexural response of supported ring-based Coriolis Vibrating Gyroscopes (CVGs) as the ring is driven into large amplitude vibration. Whilst the 2? degenerate modes have same resonance frequency in the linear regime, mechanical non-linearity
[...] Read more.
A mathematical model is developed to describe the 2? in-plane flexural response of supported ring-based Coriolis Vibrating Gyroscopes (CVGs) as the ring is driven into large amplitude vibration. Whilst the 2? degenerate modes have same resonance frequency in the linear regime, mechanical non-linearity within the support structure induces a frequency split as the vibration amplitude increases. The origins and effects of geometrical non-linearity are investigated using the proposed analytical model. Full article
Open AccessProceedings Universal Integrated Photodetector Platform
Proceedings 2018, 2(13), 756; https://doi.org/10.3390/proceedings2130756
Published: 10 December 2018
PDF Full-text (2382 KB)
Abstract
Within this work we developed a universal integrated photodetector platform for the detection, amplification and digitalization of various optical data signals. The concept features two internal plus two external photodiodes, signal amplification and output stages each. For each application a combination of the
[...] Read more.
Within this work we developed a universal integrated photodetector platform for the detection, amplification and digitalization of various optical data signals. The concept features two internal plus two external photodiodes, signal amplification and output stages each. For each application a combination of the optimal input detector, the suitable amplifier plus gain setting and the appropriate output stage can be combined individually. Full article
Open AccessProceedings Thickness-Dependent Swelling Behavior of Vapor-Deposited Hydrogel Thin Films
Proceedings 2018, 2(13), 757; https://doi.org/10.3390/proceedings2130757
Published: 3 December 2018
Viewed by 64 | PDF Full-text (471 KB)
Abstract
Hydrogel thin films containing temperature sensitive chemical functionalities (such as N-isopropylacrylamide, NIPAAm) are particularly interesting for sensor and actuator setups. Complex 3D structures can be conformally coated by the solvent free technique initiated Chemical Vapor Deposition, with precise control over chemical composition
[...] Read more.
Hydrogel thin films containing temperature sensitive chemical functionalities (such as N-isopropylacrylamide, NIPAAm) are particularly interesting for sensor and actuator setups. Complex 3D structures can be conformally coated by the solvent free technique initiated Chemical Vapor Deposition, with precise control over chemical composition and film thickness. In this study, NIPAAm-based thin films with film thicknesses ranging from tens to several hundreds of nanometers and with different amounts of cross-linking were deposited. Above the lower critical solution temperature (LCST), these films repel out water and hence shrink. The amount of cross-linking and the deposited film thickness were successfully identified to both affect shape and position of the LCST transition of these systems: a promising basis for tuning response properties. Full article
Open AccessProceedings V2O5 Thin Films as Nitrogen Dioxide Sensors
Proceedings 2018, 2(13), 759; https://doi.org/10.3390/proceedings2130759
Published: 3 December 2018
Viewed by 70 | PDF Full-text (817 KB)
Abstract
V2O5 thin films were deposited onto insulating support (either fused silica or alumina) by means of rf reactive sputtering from a metallic vanadium target. Argon-oxygen gas mixtures of different compositions controlled by the flow rates were used for sputtering. X-ray
[...] Read more.
V2O5 thin films were deposited onto insulating support (either fused silica or alumina) by means of rf reactive sputtering from a metallic vanadium target. Argon-oxygen gas mixtures of different compositions controlled by the flow rates were used for sputtering. X-ray diffraction at glancing incidence (GIXD) and Scanning Electronic Microscopy (SEM) were used for structural and phase characterization. Optical transmittance and reflectance spectra were recorded with a Lambda 19 Perkin-Elmer double spectrophotometer. Thickness of the films was determined from the profilometry. It has been confirmed by GIXD that the deposited films are composed of V2O5 phase. The estimated optical band gap was ca. 2.5 eV. The gas sensing properties of V2O5 thin films were investigated at RT-690 K towards NO2 gas of 0–20 ppm. The results indicated that material exhibited good response and reversibility towards nitrogen dioxide. Full article
Open AccessProceedings An Innovative Liquid Biosensor for the Detection of Lipid Molecules Involved in Diseases of the Nervous System
Proceedings 2018, 2(13), 760; https://doi.org/10.3390/proceedings2130760
Published: 27 November 2018
Viewed by 84 | PDF Full-text (455 KB)
Abstract
Growing evidence suggests that endocannabinoid levels are modulated during pathological conditions affecting both central and peripheral nervous system. In the present study, a novel approach (patent pending) based on an innovative liquid biosensor has been used to analyze two relevant endocannabinoid molecules with
[...] Read more.
Growing evidence suggests that endocannabinoid levels are modulated during pathological conditions affecting both central and peripheral nervous system. In the present study, a novel approach (patent pending) based on an innovative liquid biosensor has been used to analyze two relevant endocannabinoid molecules with calibration purposes: N-arachidonoylethanolamine and 2-arachidonoylglycerol. The system was able to predict both compound concentrations with a Root Mean Square Error in Cross Validation (RMSECV) of 6.61 nM and 23.50 nM, respectively. Full article
Open AccessProceedings A Sensor System for the Monitoring of Production Processes of Low FODMAP Food
Proceedings 2018, 2(13), 761; https://doi.org/10.3390/proceedings2130761
Published: 3 December 2018
Viewed by 91 | PDF Full-text (462 KB)
Abstract
Irritable bowel syndrome is one of the most common gastrointestinal disorder. Despite its high prevalence, the factors responsible for the onset of the clinical symptoms are not clear yet. Recently, there was growing evidence the origin of IBS resides in a number of
[...] Read more.
Irritable bowel syndrome is one of the most common gastrointestinal disorder. Despite its high prevalence, the factors responsible for the onset of the clinical symptoms are not clear yet. Recently, there was growing evidence the origin of IBS resides in a number of fermentable short-chain carbohydrates called FODMAPs. The present study assessed the possibility of using a multisensory system to detect the presence of FODMAPs in foods. Full article
Open AccessProceedings Films of Polyphthalocyanines for Gas Sensitivity Study at Low Temperatures
Proceedings 2018, 2(13), 762; https://doi.org/10.3390/proceedings2130762
Published: 29 November 2018
Viewed by 97 | PDF Full-text (233 KB)
Abstract
Phthalocyanines and their analogs have practical interest at development devices with low consumption because these materials are known to considerably modify their electrophysical properties on adsorption of the active gases at low temperatures. The conductivity, resistance-temperature relationship, sensor properties relative to NO, O
[...] Read more.
Phthalocyanines and their analogs have practical interest at development devices with low consumption because these materials are known to considerably modify their electrophysical properties on adsorption of the active gases at low temperatures. The conductivity, resistance-temperature relationship, sensor properties relative to NO, O2 and H2S of films based on oligo-(OPc) and polyphthalocyanines (PPc) containing Co, Cu, Fe and Mn were investigated in the present work. Polymeric films were deposited on the test structures with a pair of interdigital metal electrodes. The sensor’s active area was 4.0 × 4.0 mm, and electrode gap was egual 0.08 mm. The sensitive layers were formed by two methods. The soluble OPcs were deposited from their saturated dimethylformamide solutions and insoluble PPcs were deposited by the thermal sputtering in vacuum. The investigations were carried out under the sensor thermal stabilization conditions in the range 50–250 °C with the constant values of the heater resistance. Full article
Open AccessProceedings Experimental Demonstration of Stray-Field Immunity beyond 5 mT for an Automotive-Grade Rotary Position Sensor
Proceedings 2018, 2(13), 763; https://doi.org/10.3390/proceedings2130763
Published: 10 December 2018
PDF Full-text (497 KB)
Abstract
This paper experimentally demonstrates the stray-field robustness capability of a novel Hall-based rotary position sensor concept (Huber, S., et al, 2018). The sensor targets safety-related automotive applications, for example powertrain and power steering. In these applications, the safety requirement specifies a maximum stray-field
[...] Read more.
This paper experimentally demonstrates the stray-field robustness capability of a novel Hall-based rotary position sensor concept (Huber, S., et al, 2018). The sensor targets safety-related automotive applications, for example powertrain and power steering. In these applications, the safety requirement specifies a maximum stray-field induced error of 0.4°. Therefore, the robustness in corner cases needs to be assessed. We demonstrate the stray-field immunity in multiple corner cases for temperature from −40 °C up to 160 °C and over lifetime. The impact of a uniform 5 mT stray field over all conditions (3σ) is shown to be less than 0.25°. The fully-integrated automotive-qualified sensor is implemented in a 0.18-μm CMOS technology, and achieves 0.7° of angular accuracy. Full article
Open AccessProceedings An Optical Inclinometer Exploiting Magnetic Fluids
Proceedings 2018, 2(13), 764; https://doi.org/10.3390/proceedings2130764
Published: 30 November 2018
Viewed by 71 | PDF Full-text (733 KB)
Abstract
Among sensors using magnetic fluids, inclinometers are seriously addressed by the scientific community. This paper deals with an optical inclinometer exploiting a ferrofluid (FF) mass, a magnetic shaping system and an InfraRed (IR) readout strategy. A dedicated paradigm is also proposed, with the
[...] Read more.
Among sensors using magnetic fluids, inclinometers are seriously addressed by the scientific community. This paper deals with an optical inclinometer exploiting a ferrofluid (FF) mass, a magnetic shaping system and an InfraRed (IR) readout strategy. A dedicated paradigm is also proposed, with the aim of defining a calibration model relating the inclinometer output quantity to the imposed tilt. The working range of the inclinometer is [−15°–15°]; the sensor accuracy and resolution are 0.61° and 0.005°, respectively. Moreover, the device shows a span-to-resolution ratio of 6 × 103. Full article
Open AccessProceedings A Gas Sensor with BLE connectivity for Wearable Applications
Proceedings 2018, 2(13), 765; https://doi.org/10.3390/proceedings2130765
Published: 21 November 2018
Viewed by 108 | PDF Full-text (728 KB)
Abstract
The technological development of the last few years in the field of integrated electronic components has encouraged the use of wearable electronic devices. In the biomedical field, this improvement allows the registration and analysis of numerous values, starting from environmental parameters up to
[...] Read more.
The technological development of the last few years in the field of integrated electronic components has encouraged the use of wearable electronic devices. In the biomedical field, this improvement allows the registration and analysis of numerous values, starting from environmental parameters up to the vital parameters of a subject, without interfering with the normal daily activities of the individual. In this context, the present work is focused on the design, development and evaluation of a low power wearable and wireless electronic interface able to acquire and transmit signals generated by a gas sensor, based on electrochemical technology, to monitor air quality through the measurement of O2 and CO2 concentration. Among the existing wireless technologies, it was decided to use Bluetooth Low Energy (BLE) as it allows data transmission to multiple types of external devices, such as PCs and smartphones with low power consumption. Full article
Open AccessProceedings Imaging Fluorophore-Labelled Intestinal Tissue via Fluorescence Endoscope Capsule
Proceedings 2018, 2(13), 766; https://doi.org/10.3390/proceedings2130766
Published: 27 November 2018
Viewed by 83 | PDF Full-text (1979 KB)
Abstract
The authors have developed a wireless fluorescence imaging capsule endoscope, potentially capable of detecting early signs of disease in the human intestine which can be missed by white-light imaging (WLI) capsule endoscopy (Figure 1). Intestinal fluorescence imaging exploits variations in tissue autofluorescence between
[...] Read more.
The authors have developed a wireless fluorescence imaging capsule endoscope, potentially capable of detecting early signs of disease in the human intestine which can be missed by white-light imaging (WLI) capsule endoscopy (Figure 1). Intestinal fluorescence imaging exploits variations in tissue autofluorescence between healthy and diseased areas in response to illumination, or application of fluorescent labels which preferentially bind to diseased sites. To validate the capsule’s capability to image fluorescently-labelled tissue, a small area of a sample of ex vivo porcine small intestine was sonicated with 6 nm CdZnMg fluorescent quantum dots, and the labelled area clearly differentiated from surrounding tissue by the fluorescence imaging capsule. Full article
Open AccessProceedings A Programmable 3-Channel Acoustic Wake-Up Interface Enabling Always-On Detection of Underwater Events within 20 µA
Proceedings 2018, 2(13), 768; https://doi.org/10.3390/proceedings2130768
Published: 23 November 2018
Viewed by 107 | PDF Full-text (991 KB)
Abstract
We present an always-on acoustic wake-up sensor interface, designed for prolonging the autonomy of energy-hungry hardware for underwater acoustic surveillance. Proposed design enables the detection of a passing ship by simultaneous listening up to three arbitrarily defined frequency-bands within the 2.5 kHz range,
[...] Read more.
We present an always-on acoustic wake-up sensor interface, designed for prolonging the autonomy of energy-hungry hardware for underwater acoustic surveillance. Proposed design enables the detection of a passing ship by simultaneous listening up to three arbitrarily defined frequency-bands within the 2.5 kHz range, and generates a wake-up signal upon finding a match with a digitally preset template describing signal’s discriminatory time-frequency features. In this paper, we propose the architecture of such fully programmable, multichannel, mixed-signal wake- up circuit. We show the implementation of a PCB prototype, characterize its sensitivity, analyze its current consumption, and verify its response on real-world hydrophone recordings. It is demonstrated that the design consumes only 6.4 µA per channel (in total <20 µA) with ultra-low- power COTS components, while listening. Full article
Open AccessProceedings Study of Two Vanadium Based Materials as Working Electrode for Developing A Selective Mixed-Potential Ammonia Sensor
Proceedings 2018, 2(13), 770; https://doi.org/10.3390/proceedings2130770
Published: 23 November 2018
Viewed by 114 | PDF Full-text (586 KB)
Abstract
Mixed potential ammonia gas sensors were fabricated by using two sensing materials of Ni3V2O8 and Au-V2O5 as working electrodes, YSZ as electrolyte and platinum as reference electrode. The results have shown that the Ni3
[...] Read more.
Mixed potential ammonia gas sensors were fabricated by using two sensing materials of Ni3V2O8 and Au-V2O5 as working electrodes, YSZ as electrolyte and platinum as reference electrode. The results have shown that the Ni3V2O8 sensors show cross-sensitivity toward NO gas. However, Au-V2O5 working electrodes displayed a high sensitivity to NH3 as well as fast response and recovery times at high temperatures. Furthermore, the results indicate that the selectivity of Au-V2O5 sensors increases by increasing temperature. Full article
Open AccessProceedings Fast Enthalpy-Sensing Microsystem Operating in Continuous Flow
Proceedings 2018, 2(13), 771; https://doi.org/10.3390/proceedings2130771
Published: 28 November 2018
Viewed by 71 | PDF Full-text (712 KB)
Abstract
A new microsystem, designed to detect and measure in real time the enthalpy of mixing of two fluid-constituents is presented. A preliminary approach to arrange miniaturized batch-cells allowing detecting enthalpy of dilution or mixing is first discussed. Then, a coherent rationale leading to
[...] Read more.
A new microsystem, designed to detect and measure in real time the enthalpy of mixing of two fluid-constituents is presented. A preliminary approach to arrange miniaturized batch-cells allowing detecting enthalpy of dilution or mixing is first discussed. Then, a coherent rationale leading to structure devices operating in real time is formulated, considering the straightforward assessment of heat flux transducers (HFTs) capability. Basic thermodynamic observations regarding analogy between thermal and electrical systems are highlighted prior consideration of practical examples involving mixing of water and alcohols. Fundamentals about HFTs design are highlighted before presenting an adequate way to integrate both functions of mixing and measuring the entailed heat exchange as two continuously flowing fluids interact with each other. Then, a prototype of such a dedicated device is discussed with its relevant expected performance. Full article
Open AccessProceedings System Level Simulations of an Open Photo-Acoustic Gas Sensor
Proceedings 2018, 2(13), 773; https://doi.org/10.3390/proceedings2130773
Published: 20 November 2018
Viewed by 104 | PDF Full-text (507 KB)
Abstract
This document deals with a new approach to the system level modeling of open photo-acoustic gas sensors (PAS) for CO2 sensing applications. The complex nature of the sensor calls for a flexible co-simulation environment which combines diverse domains and physical quantities such
[...] Read more.
This document deals with a new approach to the system level modeling of open photo-acoustic gas sensors (PAS) for CO2 sensing applications. The complex nature of the sensor calls for a flexible co-simulation environment which combines diverse domains and physical quantities such as pressure, temperature, voltage and electrical power. After validation against laboratory measurements, the system model can be used to investigate different package or hardware options, to evaluate the impact of different types of coupling (e.g., electrical or acoustic) and explore new algorithms and signal processing methods for more accurate gas concentration estimates. Full article
Open AccessProceedings Optimizing Paste Formulation for Improving the Performances of CMOS-Based MOx Chemiresistors Prepared by Ink-Jet Printing
Proceedings 2018, 2(13), 774; https://doi.org/10.3390/proceedings2130774
Published: 29 November 2018
Viewed by 71 | PDF Full-text (2758 KB)
Abstract
CMOS-based devices and the control of the materials properties by nanotechnology enabled significant progresses in the field of metal chemiresistors for gas sensing applications both in terms of miniaturization and performances (e.g., gas sensitivity). In this regard, ink-jet printing is a powerful technique
[...] Read more.
CMOS-based devices and the control of the materials properties by nanotechnology enabled significant progresses in the field of metal chemiresistors for gas sensing applications both in terms of miniaturization and performances (e.g., gas sensitivity). In this regard, ink-jet printing is a powerful technique to achieve high-volume production and meet the emerging consumer market demands. The paste formulation is an obvious aspect to consider for achieving a viscosity range suitable for ink-jet printing. More importantly, it is often an underestimated task which impacts the gas response of the resulting chemiresistors in terms of sensitivity, cross-sensitivity and baseline drift. In this manuscript, the effects on the film morphology and gas response upon removing ethyl-cellulose from the paste formulation is reported. Improvements in terms of sensitivity and baseline drift were observed. Full article
Open AccessProceedings IR Absorbance as a Criterion for Temperature Compensation in Nondispersive Infrared Gas Sensor
Proceedings 2018, 2(13), 775; https://doi.org/10.3390/proceedings2130775
Published: 21 November 2018
Viewed by 106 | PDF Full-text (676 KB)
Abstract
Nondispersive infrared (NDIR) CO2 gas sensor was developed by using White-cell structure and tried to compensate the temperature effects in order to monitor CO2 concentrations without hindering the temperature variations. However, the absorptions of infrared light depend on not only the
[...] Read more.
Nondispersive infrared (NDIR) CO2 gas sensor was developed by using White-cell structure and tried to compensate the temperature effects in order to monitor CO2 concentrations without hindering the temperature variations. However, the absorptions of infrared light depend on not only the temperatures but also CO2 concentrations. Thus, a single Beer-Lambert law couldn’t properly describe the tendency of voltage decrements within full scale input (FSI, 0 to 5000 ppm) because it was affected by both parameters. In this article, the absorbance of infrared light is defined according to the concentrations of CO2 gas. Then, a new temperature compensation algorithm has been implemented into micro-controller unit (MCU), the measurement errors were within ±3.6% as the temperature-dependent absorbance was chosen at 1450 ppm CO2 concentrations. Full article
Open AccessProceedings On-Chip Thermal Insulation Using Porous GaN
Proceedings 2018, 2(13), 776; https://doi.org/10.3390/proceedings2130776
Published: 10 December 2018
PDF Full-text (348 KB)
Abstract
This study focuses on the thermal characterization of porous gallium nitride (GaN) using
an extended 3ω method. Porous semiconductor materials provide a solution to the need for on-chip
thermal insulation, a fundamental requirement for low-power, high-speed and high-accuracy
thermal sensors. Thermal insulation is
[...] Read more.
This study focuses on the thermal characterization of porous gallium nitride (GaN) using
an extended 3ω method. Porous semiconductor materials provide a solution to the need for on-chip
thermal insulation, a fundamental requirement for low-power, high-speed and high-accuracy
thermal sensors. Thermal insulation is especially important in GaN devices, due to the intrinsically
high thermal conductivity of the material. The results show one order of magnitude reduction in
thermal conductivity, from 130 W/mK to 10 W/mK, in line with theoretical predictions for porous
materials. This achievement is encouraging in the quest for integrating sensors with opto-, powerand
RF-electronics on a single GaN chip. Full article
Open AccessProceedings Performance Degradations of MISFET-Based Hydrogen Sensors with Pd-Ta2O5-SiO2-Si Structure at Long-Time Operation
Proceedings 2018, 2(13), 777; https://doi.org/10.3390/proceedings2130777
Published: 10 December 2018
PDF Full-text (407 KB)
Abstract
There are presented the generalized results of studies of performance degradation of hydrogen sensors based on MISFET with structure Pd-Ta2O5-SiO2-Si. It was shown how responses’ parameters change during long-term tests of sensors under repeated hydrogen impacts. There
[...] Read more.
There are presented the generalized results of studies of performance degradation of hydrogen sensors based on MISFET with structure Pd-Ta2O5-SiO2-Si. It was shown how responses’ parameters change during long-term tests of sensors under repeated hydrogen impacts. There were found two stages of time-dependence response’ instability, the degradation degree of which depends on operating conditions, hydrogen concentrations and time. To interpret results there were proposed the models, parameters of which were calculated using experimental data. These models can be used to predict performances of MISFET-based devices for long-time operation. Full article
Open AccessProceedings Photoelectrochemical Imaging Using Carbon Dots (CDs) Derived from Chitosan
Proceedings 2018, 2(13), 778; https://doi.org/10.3390/proceedings2130778
Published: 10 December 2018
PDF Full-text (598 KB)
Abstract
Carbon dots (CDs) derived from chitosan via a solvothermal method were covalently
linked to an indium tin oxide (ITO) surface and showed a direct photoelectrochemical response.
We attribute the photocurrent of the ITO-silane-CD surface to a photogenerated electron-transfer
process by CDs under illumination.
[...] Read more.
Carbon dots (CDs) derived from chitosan via a solvothermal method were covalently
linked to an indium tin oxide (ITO) surface and showed a direct photoelectrochemical response.
We attribute the photocurrent of the ITO-silane-CD surface to a photogenerated electron-transfer
process by CDs under illumination. The ITO-silane-CD surface was successfully used for
ac-photocurrent imaging. This opens up new applications for CDs as biocompatible and
light-addressable electrochemical sensors in bioimaging applications. Full article
Open AccessProceedings A Thin-Film Thermoelectric Generator for Large-Area Applications
Proceedings 2018, 2(13), 779; https://doi.org/10.3390/proceedings2130779
Published: 10 December 2018
PDF Full-text (575 KB)
Abstract
A thin-film thermoelectric generator (TEG) applying a novel folded design where both the heat flux and current flow are in the plane of the thin-film is presented. The performance of the first fabricated devices is demonstrated and the results compared with the computational
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A thin-film thermoelectric generator (TEG) applying a novel folded design where both the heat flux and current flow are in the plane of the thin-film is presented. The performance of the first fabricated devices is demonstrated and the results compared with the computational ones. The produced power is analyzed against the power requirements of a wireless sensor node and it is shown that a thermoelectric module of the area of <1 m2 consisting of the novel TEG units is able to power a wireless sensor node of various sensors applicable e.g., to environmental monitoring of a building. The integration of energy-autonomous sensors for multifunctional smart windows providing the required temperature gradient is anticipated. Full article
Open AccessProceedings Bio-Impedance Non-Contact Radiofrequency Sensor for the Characterization of Burn Depth in Organic Tissues
Proceedings 2018, 2(13), 780; https://doi.org/10.3390/proceedings2130780 (registering DOI)
Published: 13 December 2018
PDF Full-text (687 KB)
Abstract
flat circular transmission-line based 300 MHz resonator is implemented for the noncontact
assessment of burn depths in biological tissue. Used as a transmit-and-receive sensor, it is
placed here at a 2 mm distance from organic material test samples (pork fillet samples) which have
[...] Read more.
flat circular transmission-line based 300 MHz resonator is implemented for the noncontact
assessment of burn depths in biological tissue. Used as a transmit-and-receive sensor, it is
placed here at a 2 mm distance from organic material test samples (pork fillet samples) which have
been previously heated on one face in various heating conditions involving various temperatures,
durations and procedures. Data extracted from the sensor by means of a distant monitoring coil
were found to clearly correlate with the depth of burn observed on the tissue samples (up to 40%
sensor output changes for a 7 mm burn depth) and with the heating conditions (around 5% sensor
output changes for 5.5 mm burn depth obtained at 75 °C or 150 °C). These results open the way to
the development of easy to implement burn assessment and monitoring techniques, which could be
integrated in wearable medical dressing-like monitoring devices. Full article
Open AccessProceedings How to Detect Selectively Hydrogen and Hydrogen Containing Gases with Metal Oxide Gas Sensor Operating in Non-Stationary Thermal Regime?
Proceedings 2018, 2(13), 782; https://doi.org/10.3390/proceedings2130782
Published: 10 December 2018
PDF Full-text (800 KB)
Abstract
We demonstrated the possibility of selective detection of hydrogen, ethanol, hydrogen sulfide, carbon monoxide, methane and ammonia gas using metal oxide gas sensor operating in non-stationary thermal regime. This non-stationary regime consists in fast heating of the sensing layer to high temperature followed
[...] Read more.
We demonstrated the possibility of selective detection of hydrogen, ethanol, hydrogen sulfide, carbon monoxide, methane and ammonia gas using metal oxide gas sensor operating in non-stationary thermal regime. This non-stationary regime consists in fast heating of the sensing layer to high temperature followed by temperature stabilization at lower temperature. The analysis of the shape of the curve describing the sensor resistance as a function of time during this measurement cycle enables the quantitative analysis of gas mixture. The investigation of kinetics of the process in non-stationary regime permits to understand the mechanism of the processes on the surface of sensing material. Full article
Open AccessProceedings Novel 3D-Printed MEMS Magnetometer with Optical Detection
Proceedings 2018, 2(13), 783; https://doi.org/10.3390/proceedings2130783
Published: 23 November 2018
Viewed by 123 | PDF Full-text (1422 KB)
Abstract
This paper reports a novel 3D printed MEMS magnetometer with optical readout, which demonstrates the advantages of 3D printing technology in terms of rapid prototyping. Low-cost and fast product development cycles favour 3D printing as an effective tool. Sensitivity measurement with such devices
[...] Read more.
This paper reports a novel 3D printed MEMS magnetometer with optical readout, which demonstrates the advantages of 3D printing technology in terms of rapid prototyping. Low-cost and fast product development cycles favour 3D printing as an effective tool. Sensitivity measurement with such devices indicate high accuracy and good structural performance, considering material and technological uncertainties. This paper is focusing on the novelty of the rapid, 3D-printing prototyping approach and verification of the working principle for printed MEMS magnetometers. Full article
Open AccessProceedings 3D-Printed MEMS Magnetometer Featuring Compliant Mechanism
Proceedings 2018, 2(13), 784; https://doi.org/10.3390/proceedings2130784
Published: 23 November 2018
Viewed by 118 | PDF Full-text (2200 KB)
Abstract
This paper reports a novel 3D-printed MEMS resonant magnetometer with optical readout which features a mechanical conversion of a vertical oscillation into a horizontal one. This demonstrates the advantages of 3D-printing technology in terms of rapid prototyping, low costs and fast product development
[...] Read more.
This paper reports a novel 3D-printed MEMS resonant magnetometer with optical readout which features a mechanical conversion of a vertical oscillation into a horizontal one. This demonstrates the advantages of 3D-printing technology in terms of rapid prototyping, low costs and fast product development cycles. In addition, 3D-printing enables ‘true’ three-dimensional MEMS structures in contrast to the traditional MEMS technology which allows only two dimensional structures. The measurement approach comprises a hybrid implementation of an optical modulator, an LED and a photodetector. Full article
Open AccessProceedings Polypyrrole Based Love-Wave Gas Sensor Devices with Enhanced Properties to Ammonia
Proceedings 2018, 2(13), 786; https://doi.org/10.3390/proceedings2130786
Published: 23 November 2018
Viewed by 113 | PDF Full-text (426 KB)
Abstract
Love-wave (LW) sensors based on gas sensitive polypyrrole (PPy) nanoparticles (NPs) and their modification with different gold (Au) loads are developed in this work. The research is focused on the fabrication process of the gas sensor devices and their sensing properties to ammonia
[...] Read more.
Love-wave (LW) sensors based on gas sensitive polypyrrole (PPy) nanoparticles (NPs) and their modification with different gold (Au) loads are developed in this work. The research is focused on the fabrication process of the gas sensor devices and their sensing properties to ammonia (NH3). Full article
Open AccessProceedings UV Light Assisted NO2Sensing by SnO2/Graphene Oxide Composite
Proceedings 2018, 2(13), 787; https://doi.org/10.3390/proceedings2130787
Published: 23 November 2018
Viewed by 110 | PDF Full-text (813 KB)
Abstract
Nitric oxide (NO2) is one of the air pollutants that pose serious environmental concerns over the years. In this study, SnO2 nanowires were synthesized by evaporation-condensation method and graphene oxide were synthesized using modified Hummers method for low temperature NO
[...] Read more.
Nitric oxide (NO2) is one of the air pollutants that pose serious environmental concerns over the years. In this study, SnO2 nanowires were synthesized by evaporation-condensation method and graphene oxide were synthesized using modified Hummers method for low temperature NO2 detection. Drop cast method was used to transfer graphene oxide (GO), to form composite GO-metal oxide p-n junctions. With integration of reduce graphene oxide (rGO), the UV light absorption was enhanced. This metal oxide composite has shown a reversible response in detecting low concentrations of NO2 under UV irradiation, with a working temperature range of 50–150 °C. Pure SnO2 shows 20% response to NO2 (4 ppm) in dark conditions, while the response increasesupto60%usingUVirradiationat50°C.Furthermore, SnO2/rGOshowsa40%ofresponse in dark, while the response increases to 160% under UV light illumination. This composite exhibits excellent recovery and maintains the baseline under UV light at low temperatures, which effectively overcome the drawbacks of low recovery typically shown by metal oxide gas sensors at low temperature. Full article
Open AccessProceedings Borosilicate Glass MEMS Lorentz Force Magnetometer
Proceedings 2018, 2(13), 788; https://doi.org/10.3390/proceedings2130788
Published: 23 November 2018
Viewed by 96 | PDF Full-text (2576 KB)
Abstract
This paper reports on a novel, miniaturized magnetomechanical transducer/sensor made of borosilicate glass with wide dynamic range. The prototype is manufactured with laser micromachining and ablation techniques. Compared to state of the art, borosilicate glass substrate offers the highest thermal shock resistance and
[...] Read more.
This paper reports on a novel, miniaturized magnetomechanical transducer/sensor made of borosilicate glass with wide dynamic range. The prototype is manufactured with laser micromachining and ablation techniques. Compared to state of the art, borosilicate glass substrate offers the highest thermal shock resistance and is best suited for MEMS magnetometers, for aerospace and space applications or magnetic monitoring systems for diagnostics and plasma stability control of nuclear fusion experiments, where thermal shock resistance is a critical requirement. Full article
Open AccessProceedings Graphene-Oxide and Hydrogel Coated FBG-Based pH Sensor for Biomedical Applications
Proceedings 2018, 2(13), 789; https://doi.org/10.3390/proceedings2130789
Published: 3 December 2018
Viewed by 76 | PDF Full-text (419 KB)
Abstract
A hydrogel coated fibre grating-based pH sensor for biomedical applications has been realised, where Graphene Oxide (GO) had been used to enhance the bonding between the coating and the fibre. Two methods of deposition of GO were analysed i.e., evaporation and co-electroplating. The
[...] Read more.
A hydrogel coated fibre grating-based pH sensor for biomedical applications has been realised, where Graphene Oxide (GO) had been used to enhance the bonding between the coating and the fibre. Two methods of deposition of GO were analysed i.e., evaporation and co-electroplating. The paper concludes that the system of GO evaporated on the fibre + the hydrogel has a sensitivity much higher, (6.1 ± 0.5) pm/pH, than the system of Cu and GO co-electroplated + the hydrogel, (1.9 ± 0.1) pm/pH, for a pH range between 2 to 10. The other conclusion is that the first system has a less coating bonding energy with the optical fibre whereas the second system has a stronger bonding energy, with better durability. Full article
Open AccessProceedings Room Temperature Ethanol Microsensors Based on Silanized Tungsten Oxide Nanowires
Proceedings 2018, 2(13), 790; https://doi.org/10.3390/proceedings2130790
Published: 22 November 2018
Viewed by 120 | PDF Full-text (741 KB)
Abstract
Gas microsensors based on tungsten oxide (WO3-x) nanowires (NWs) silanized with APTES (3-aminopropyltriethoxysilane) are developed in this work. These surface modified microsensors are highly sensitive to ethanol at room temperature (RT) via photoactivation and show enhanced selectivity towards other volatile organic
[...] Read more.
Gas microsensors based on tungsten oxide (WO3-x) nanowires (NWs) silanized with APTES (3-aminopropyltriethoxysilane) are developed in this work. These surface modified microsensors are highly sensitive to ethanol at room temperature (RT) via photoactivation and show enhanced selectivity towards other volatile organic compounds (VOCs) including acetone and toluene. Full article
Open AccessProceedings A New Type of LSPR Sensor Featuring Immobilized Liposome or Phospholipid Single Layer
Proceedings 2018, 2(13), 791; https://doi.org/10.3390/proceedings2130791
Published: 4 December 2018
Viewed by 83 | PDF Full-text (500 KB)
Abstract
We have fabricated a new type of LSPR sensor featuring immobilized liposome or phospholipid single layer. LSPR principally shows an ultrahigh sensitivity on surface dielectric environmental change due to interaction with target, but little has been reported so far on applying phospholipid membranes
[...] Read more.
We have fabricated a new type of LSPR sensor featuring immobilized liposome or phospholipid single layer. LSPR principally shows an ultrahigh sensitivity on surface dielectric environmental change due to interaction with target, but little has been reported so far on applying phospholipid membranes and/or liposomes as model cell membrane. We newly tried to investigate biosensing capabilities using the membranes of the both structures on Au nanostructures of LSPR sensor chip. As a result, it was confirmed that the phospholipid single layer is more effective to improve the sensitivity than the liposome. Finally, we have clearly detected 100 nM target protein of CAB and estimated a possible detection of 10 nM range from wavelength resolution by interaction with the phospholipid single layer. Full article
Open AccessProceedings Robust Calorimetric Micro-Sensor for Aerodynamic Applications
Proceedings 2018, 2(13), 794; https://doi.org/10.3390/proceedings2130794
Published: 27 November 2018
Viewed by 112 | PDF Full-text (780 KB)
Abstract
This paper reports a calorimetric micro-sensor designed for aerodynamic applications. Measuring both the amplitude and the sign of the wall shear stress at small length-scale and high frequencies, the micro-sensor is particularly suited for flow separation detection and flow control. The micro-sensor was
[...] Read more.
This paper reports a calorimetric micro-sensor designed for aerodynamic applications. Measuring both the amplitude and the sign of the wall shear stress at small length-scale and high frequencies, the micro-sensor is particularly suited for flow separation detection and flow control. The micro-sensor was calibrated in static and dynamic in a turbulent boundary layer wind tunnel. Several micro-sensors were embedded in various configurations for measuring the shear stress and detecting flow separation. Specially, one was embedded inside an actuator slot for in situ measurements and twelve, associated with miniaturized electronics, were implemented on a flap model for active flow control experiments. Full article
Open AccessProceedings Response Characteristics of Silicon Microring Resonator Hydrogen Sensor
Proceedings 2018, 2(13), 795; https://doi.org/10.3390/proceedings2130795
Published: 22 November 2018
Viewed by 136 | PDF Full-text (789 KB)
Abstract
A silicon microring-resonator (MRR) hydrogen sensor which utilizes platinum-loaded tungsten oxide (Pt/WO3) thin film was fabricated and evaluated. The uniform film was deposited on MRR portion by using sol-gel technique. By the exposure to pure hydrogen gas, the sensor devise showed
[...] Read more.
A silicon microring-resonator (MRR) hydrogen sensor which utilizes platinum-loaded tungsten oxide (Pt/WO3) thin film was fabricated and evaluated. The uniform film was deposited on MRR portion by using sol-gel technique. By the exposure to pure hydrogen gas, the sensor devise showed the large resonant wavelength shift at room temperature. It is suggested that the change in the optical properties of hydrogen sensitive layer results in this response. Full article
Open AccessProceedings Sensitivity Comparison of Integrated Mid-Infrared Silicon-Based Photonic Detectors
Proceedings 2018, 2(13), 796; https://doi.org/10.3390/proceedings2130796
Published: 30 November 2018
Viewed by 102 | PDF Full-text (483 KB)
Abstract
Integrated silicon photonics in the mid-infrared is a promising platform for cheap and miniaturized chemical sensors, including gas and/or liquid sensors for environmental monitoring and the consumer electronics market. One major challenge in integrated photonics is the design of an integrated detector sensitive
[...] Read more.
Integrated silicon photonics in the mid-infrared is a promising platform for cheap and miniaturized chemical sensors, including gas and/or liquid sensors for environmental monitoring and the consumer electronics market. One major challenge in integrated photonics is the design of an integrated detector sensitive enough to detect minimal changes in light intensity resulting from, for example, the absorption by the analyte. Further complexity arises from the need to fabricate such detectors at a high throughput with high requirements on fabrication tolerances. Here we analyze and compare the sensitivity of three different chip-integrated detectors at a wavelength of 4.17 µm, namely a resistance temperature detector (RTD), a diode and a vertical-cavity enhanced resonant detector (VERD). Full article
Open AccessProceedings A Microfabricated 4-Electrode Conductivity Sensor with Enhanced Range
Proceedings 2018, 2(13), 797; https://doi.org/10.3390/proceedings2130797
Published: 10 December 2018
PDF Full-text (708 KB)
Abstract
Conductivity is a routinely measured parameter to assess impurities in water. Changing the geometry from parallel plate electrodes to planar microfabricated dual-band or interdigitated electrodes, these sensors could be miniaturized. Based on this approach, we designed 2-electrode conductivity sensors and compared their performance
[...] Read more.
Conductivity is a routinely measured parameter to assess impurities in water. Changing the geometry from parallel plate electrodes to planar microfabricated dual-band or interdigitated electrodes, these sensors could be miniaturized. Based on this approach, we designed 2-electrode conductivity sensors and compared their performance with a commercially available device. Adding another electrode pair (either as dual-band or meandering between interdigitated electrodes), a 4-electrode sensor was formed for which the measuring range could be enhanced to 3 × 10−6–12 × 10−3 S/cm. Full article
Open AccessProceedings A Back-Illuminated Time-of-Flight Image Sensor with SOI-Based Fully Depleted Detector Technology for LiDAR Application
Proceedings 2018, 2(13), 798; https://doi.org/10.3390/proceedings2130798
Published: 22 November 2018
Viewed by 369 | PDF Full-text (887 KB)
Abstract
A back-illuminated time-of-flight (ToF) image sensor based on a 0.2 µm silicon-on-insulator (SOI) CMOS detector technology using fully-depleted substrate is developed for the light detection and ranging (LiDAR) applications. A fully-depleted 200 µm-thick bulk silicon is used for the higher quantum efficiency (QE)
[...] Read more.
A back-illuminated time-of-flight (ToF) image sensor based on a 0.2 µm silicon-on-insulator (SOI) CMOS detector technology using fully-depleted substrate is developed for the light detection and ranging (LiDAR) applications. A fully-depleted 200 µm-thick bulk silicon is used for the higher quantum efficiency (QE) in a near-infrared (NIR) region. The developed SOI pixel structure has a 4-tapped charge modulator with a draining function to achieve a higher range resolution and to cancel background light signal. A distance is measured up to 27 m with a range resolution of 12 cm at the outdoor and average light power density is 150 mW/m2@30 m. Full article
Open AccessProceedings Numerical Investigations of Infrared Slot Waveguides for Gas Sensing
Proceedings 2018, 2(13), 799; https://doi.org/10.3390/proceedings2130799
Published: 30 November 2018
Viewed by 77 | PDF Full-text (833 KB)
Abstract
Sensing of gases is a promising area for applications of photonic sensor devices that operate in the mid-infrared spectral range. We present a numerical investigation of slot waveguides for evanescent field sensing of CO2. The sensor platform is a poly-silicon slot
[...] Read more.
Sensing of gases is a promising area for applications of photonic sensor devices that operate in the mid-infrared spectral range. We present a numerical investigation of slot waveguides for evanescent field sensing of CO2. The sensor platform is a poly-silicon slot waveguide on silicon dioxide, where both layers are deposited on a standard silicon substrate. The evanescent field ratio, which is a crucial parameter for the sensing performance of the waveguides, was determined and values as high as 42% were obtained. Full article
Open AccessProceedings Application of a Novel Low-Cost Hyperspectral Imaging Setup Operating in the Mid-Infrared Region
Proceedings 2018, 2(13), 800; https://doi.org/10.3390/proceedings2130800
Published: 30 November 2018
Viewed by 73 | PDF Full-text (648 KB)
Abstract
In this contribution, we demonstrate the realization and application of a low-cost, flexible, small and fast hyperspectral imaging approach operating in the midinfrared fingerprint region where most molecules exhibit their fundamental vibrations. Following this approach, the recording of chemical images of macroscopic-sized samples
[...] Read more.
In this contribution, we demonstrate the realization and application of a low-cost, flexible, small and fast hyperspectral imaging approach operating in the midinfrared fingerprint region where most molecules exhibit their fundamental vibrations. Following this approach, the recording of chemical images of macroscopic-sized samples at standoff distances in reflection geometry is possible. The optical setup is based on spectral identification by means of a MEMS-based Fabry-Pérot interferometer combined with 2D-snapshot spatial resolution using a bolometer camera. Results show the successful spatially resolved (resolution below 500 µm) chemical identification of different samples deposited on a metal surface (FOV = 6 × 5 cm) at a working distance of 35 cm. Full article
Open AccessProceedings Operando Investigations of Rare-Earth Oxycarbonate CO2 Sensors
Proceedings 2018, 2(13), 801; https://doi.org/10.3390/proceedings2130801
Published: 26 November 2018
Viewed by 106 | PDF Full-text (481 KB)
Abstract
In this work, we have succeeded in synthesizing monoclinic and hexagonal La2O2CO3 using two different routes and revealed that both of them are sensitive to CO2 to the same degree. Moreover, we observed that the resistance of
[...] Read more.
In this work, we have succeeded in synthesizing monoclinic and hexagonal La2O2CO3 using two different routes and revealed that both of them are sensitive to CO2 to the same degree. Moreover, we observed that the resistance of the sensor based on hexagonal phase is much higher and more stable than the one of the sensors based on the monoclinic phase. Using Operando and time resolved XRD measurements, we have also demonstrated that the resistivity of the sensor based on monoclinic La2O2CO3 increases because of the material transformation into the hexagonal phase during an exemplarily aging process. Full article
Open AccessProceedings Fully Screen Printed Carbon Black-Only Thermocouple and the Corresponding Seebeck Coefficients
Proceedings 2018, 2(13), 802; https://doi.org/10.3390/proceedings2130802
Published: 30 November 2018
Viewed by 75 | PDF Full-text (1427 KB)
Abstract
This work presents a thermocouple that is fully screen printed and consists exclusively of carbon black conductors. Two different carbon black inks were printed to form a thermocouple, which has been characterized regarding its output voltage. For reference, each of the carbon black
[...] Read more.
This work presents a thermocouple that is fully screen printed and consists exclusively of carbon black conductors. Two different carbon black inks were printed to form a thermocouple, which has been characterized regarding its output voltage. For reference, each of the carbon black inks was used in combination with gold to form two further thermocouples. These have also been characterized and the output voltage used to predict the output of the associated thermocouple consisting of pure carbon black conductors. The results have been compared with the measurement results and show that the output of the pure carbon black thermocouple is roughly 10% lower than expected. Full article
Open AccessProceedings A Screen Printed Thermocouple-Array on a Flexible Substrate for Condition Monitoring
Proceedings 2018, 2(13), 803; https://doi.org/10.3390/proceedings2130803
Published: 30 November 2018
Viewed by 71 | PDF Full-text (1121 KB)
Abstract
This work deals with the realization of a fully printed thermocouple-array on a flexible substrate for condition monitoring applications. The thermocouple-array consisting of carbon black and silver was fabricated on PET-foil in a screen printing process and characterized up to a junction temperature
[...] Read more.
This work deals with the realization of a fully printed thermocouple-array on a flexible substrate for condition monitoring applications. The thermocouple-array consisting of carbon black and silver was fabricated on PET-foil in a screen printing process and characterized up to a junction temperature of 150 °C. To ensure that no spurious voltages of the thermocouple occur due to deformations of the flexible substrate, the cross-sensitivity to deformation of the foil was investigated as well. Finally, as a test case, the temperature gradient of a plastic bar heated on a single end was measured with the thermocouple-array. Full article
Open AccessProceedings Colorimetric Detection of Hydrogen Sulfide in Ambient Air
Proceedings 2018, 2(13), 804; https://doi.org/10.3390/proceedings2130804
Published: 21 November 2018
Viewed by 108 | PDF Full-text (611 KB)
Abstract
We present a fast method to monitor hydrogen sulfide (H2S) in ambient air based on a visible color change. Therefore, an immobilized copper(II) complex of the azo dye 1-(2-pyridylazo)-2-naphtol (H-PAN) was synthesized and prepared in a matrix for screen printing. Different
[...] Read more.
We present a fast method to monitor hydrogen sulfide (H2S) in ambient air based on a visible color change. Therefore, an immobilized copper(II) complex of the azo dye 1-(2-pyridylazo)-2-naphtol (H-PAN) was synthesized and prepared in a matrix for screen printing. Different materials, reaching from opaque paper to transparent foils served as substrate. The reaction of the copper(II) complex (Cu-PAN) to the target gas H2S was measured in reflection via UV/VIS spectroscopy. Full article
Open AccessProceedings Piezoelectric Sensors for Lamb Waves’ Direction of Arrival (DoA) Estimation
Proceedings 2018, 2(13), 806; https://doi.org/10.3390/proceedings2130806
Published: 22 November 2018
Viewed by 108 | PDF Full-text (307 KB)
Abstract
A novel strategy to design piezoelectric sensor clusters suited for direction of arrival (DoA) estimation of Lamb waves is presented in this work. The designed clusters are composed by three piezoelectric patches (P1, P2 e P3) to be bonded on the structure to
[...] Read more.
A novel strategy to design piezoelectric sensor clusters suited for direction of arrival (DoA) estimation of Lamb waves is presented in this work. The designed clusters are composed by three piezoelectric patches (P1, P2 e P3) to be bonded on the structure to be inspected. In particular, by exploiting the Radon Transform, the proposed sensor design procedure computes the shape of P2 given the shape of P1 so that the difference in time of arrival (DToA) of the Lamb waves at the two patches is linearly related to the DoA. Such properties allow to minimize the DoA uncertainty. The sensor P3 is designed to perform the estimation of DoA without knowing the actual wave velocity. Numerical results show that DoA is extremely robust. Full article
Open AccessProceedings A Micromechanical Binary Counter with MEMS-Based Digital-to-Analog Converter
Proceedings 2018, 2(13), 807; https://doi.org/10.3390/proceedings2130807
Published: 21 November 2018
Viewed by 104 | PDF Full-text (1079 KB)
Abstract
Autonomous sensors are of interest in all cases where a continuous power source is not available or difficult to realize. Besides harvesting of electrical energy for a complex storage system, it is of interest to directly store an event in a non-electrical storage,
[...] Read more.
Autonomous sensors are of interest in all cases where a continuous power source is not available or difficult to realize. Besides harvesting of electrical energy for a complex storage system, it is of interest to directly store an event in a non-electrical storage, but in a way that allows a later electrical read-out. Therefore, a miniaturized micromechanical binary counter is presented, which enables counting of threshold events, such as exceeding temperature limits or high mechanical shocks. An electro-mechanical digital-to-analog converter integrated in the binary counter is demonstrated as an option for monolithic electrical read-out of the mechanically stored information. Full article
Open AccessProceedings Heat Flow Measurement by A Force and Thermal Sensor Stick for Robots with A Nerve-Net LSI Chip
Proceedings 2018, 2(13), 808; https://doi.org/10.3390/proceedings2130808
Published: 6 December 2018
Viewed by 40 | PDF Full-text (846 KB)
Abstract
Assistant robots need a tactile sensing system. We propose a tactile sensor head with a nerve-net sensing system which measures force, temperature and heat flow with a heater simultaneously on a robot finger. For accurate heat flow measurements, it is necessary to stabilize
[...] Read more.
Assistant robots need a tactile sensing system. We propose a tactile sensor head with a nerve-net sensing system which measures force, temperature and heat flow with a heater simultaneously on a robot finger. For accurate heat flow measurements, it is necessary to stabilize the contact conditions between the sensor head and an object. A sensor stick which consists of the sensor head and an actuator was fabricated to control applied force. Heat flow measurements in three materials of different thermal conductivities such as polyethylene, glass and Aluminum were made with the sensor stick. As a result, three materials were discriminated clearly by heat flow peak values, saturations values and time constants. The tactile sensor stick with temperature measurement and force control is useful to discriminate materials of objects. Full article
Open AccessProceedings A Gradiometric Magnetic Sensor System for Stray-Field-Immune Rotary Position Sensing in Harsh Environment
Proceedings 2018, 2(13), 809; https://doi.org/10.3390/proceedings2130809 (registering DOI)
Published: 13 December 2018
PDF Full-text (1370 KB)
Abstract
Contactless magnetic position sensors are used in countless industrial and automotive applications. However, as a consequence of the electrification trend the sensors can be exposed to parasitic magnetic stray fields, and their desired robustness may be compromised. In this paper we publish for
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Contactless magnetic position sensors are used in countless industrial and automotive applications. However, as a consequence of the electrification trend the sensors can be exposed to parasitic magnetic stray fields, and their desired robustness may be compromised. In this paper we publish for the first time how this challenge is addressed and constructively solved using a complete paradigm change leaving conventional magnetic field measurement behind and entering into the realm of magnetic field gradient measurement. Our novel sensor system consists of an integrated Hall sensor realized in 0.18 μm CMOS technology with magnetic concentrators and a four-pole permanent magnet. The intrinsic angular accuracy was assessed comparing the rotary position of the permanent magnet with the sensor output showing angle errors below 0.3°. Additional end-of-line calibration can be applied using built-in memory and processing capability to further increase the accuracy. Finally, we demonstrate the immunity against stray fields of 4000 A/m which led to errors below 0.1°, corresponding to 0.06% of the sensors fullscale angular range. In conclusion, this novel sensor system offers a compact and flexible solution for stray-field immune rotary position measurement in harsh environment. Full article
Open AccessProceedings Design and Manufacturing of a Disposable, Cyclo-Olefin Copolymer, Microfluidic Biosensor
Proceedings 2018, 2(13), 810; https://doi.org/10.3390/proceedings2130810
Published: 23 November 2018
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Abstract
This contribution outlines the design and manufacturing of a biosensor for retrieval and detection of bacteria RNA. The device is fully made of Cyclo-Olefin Copolymer (COC), which features low auto-fluorescence, biocompatibility and manufacturability by hot-embossing. The RNA retrieval is carried on after bacteria
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This contribution outlines the design and manufacturing of a biosensor for retrieval and detection of bacteria RNA. The device is fully made of Cyclo-Olefin Copolymer (COC), which features low auto-fluorescence, biocompatibility and manufacturability by hot-embossing. The RNA retrieval is carried on after bacteria heat-lysis by an on-chip micro-heater. Two additional carbon resistive temperature sensors printed on the biochip sealing film monitor the heating process. RNA is hybridized with capture probes on the reaction chamber surface and identification is achieved by detection of fluorescence tags. The application of the mentioned techniques and materials facilitates the development of low-cost, disposable albeit multi-functional microfluidic system, performing heating, temperature sensing and chemical reaction processes in the same device. By proving its effectiveness, this device contributes a reference to show the potential of fully thermoplastic devices as biosensors. Full article
Open AccessProceedings Method to Study Water Diffusion into Polymers
Proceedings 2018, 2(13), 812; https://doi.org/10.3390/proceedings2130812
Published: 30 November 2018
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Abstract
We designed and realized a low cost relative humidity (RH) capacitive sensor having an interdigitated transducer coated with a cheap sensing material working at room temperature (polyimide). Thermally perturbed diffusion of water molecules into the polyimide layer is studied by heating the sensor
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We designed and realized a low cost relative humidity (RH) capacitive sensor having an interdigitated transducer coated with a cheap sensing material working at room temperature (polyimide). Thermally perturbed diffusion of water molecules into the polyimide layer is studied by heating the sensor locally and measuring the sensor capacitance change. The swelling and deswelling model is applied to determine the time constant of involved processes. This simple method, using an evaluation kit developed by our group, to measure the sensor capacitance and to study the diffusion process of water molecules into polyimide could be generalized to analyze the gas diffusion processes into polymer based sensing layer generally used in the field of gas chemical sensors. Full article
Open AccessProceedings SU-8 Based Waveguide for Optrodes
Proceedings 2018, 2(13), 814; https://doi.org/10.3390/proceedings2130814
Published: 30 November 2018
Viewed by 91 | PDF Full-text (756 KB)
Abstract
Neural probes can be equipped with light for optogenetics applications. Different approaches are used for delivering light to the tissue: an optical fiber coupled to the probe, a µLED or a waveguide integrated on the probe. Small probe dimensions, adequate optical power for
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Neural probes can be equipped with light for optogenetics applications. Different approaches are used for delivering light to the tissue: an optical fiber coupled to the probe, a µLED or a waveguide integrated on the probe. Small probe dimensions, adequate optical power for photostimulation and good tissue penetration for in-vivo experiments are critical requirements. Thus, integrating a waveguide is a promising solution. This work shows the design and simulation of a SU-8 based waveguide for integration in a neural probe. The waveguide contains 3 apertures, spaced by 0.5 mm, which will allow the photostimulation of different brain regions simultaneously. Full article
Open AccessProceedings Bi2Te3 and Sb2Te3 Thin Films with Enhanced Thermoelectric Properties for Flexible Thermal Sensors
Proceedings 2018, 2(13), 815; https://doi.org/10.3390/proceedings2130815
Published: 11 December 2018
PDF Full-text (839 KB)
Abstract
The influence of substrate type in boosting thermoelectric properties of co-evaporated Bi2Te3 and Sb2Te3 films (with 400 nm-thick) is here reported. Optimized power factor values are 2.7 × 10−3 W K−2 m−1 and 1.4 × 10−3 W K−2
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The influence of substrate type in boosting thermoelectric properties of co-evaporated Bi2Te3 and Sb2Te3 films (with 400 nm-thick) is here reported. Optimized power factor values are 2.7 × 10−3 W K−2 m−1 and 1.4 × 10−3 W K−2 m−1 for flexible Bi2Te3 and Sb2Te3 films, respectively. This is an important result as it is at least 2 times higher than the power factor found in the literature for flexible Bi2Te3 and Sb2Te3 films. A flexible infrared thermopile sensor was developed with high detectivity (2.50 × 107 cm √HzW−1). Full article
Open AccessProceedings Exploring the Potential of Electroplated Chips towards Biomedical Sensing and Diagnostics
Proceedings 2018, 2(13), 817; https://doi.org/10.3390/proceedings2130817
Published: 4 December 2018
Viewed by 84 | PDF Full-text (655 KB) | Supplementary Files
Abstract
In the past decade the significant progress in the cellular stress response was witnessed. Nevertheless, the development of the minimally-invasive and accurate sensing tools for the identification of the increasing number of potentially relevant species in clinical diagnostics, using smaller sample volumes is
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In the past decade the significant progress in the cellular stress response was witnessed. Nevertheless, the development of the minimally-invasive and accurate sensing tools for the identification of the increasing number of potentially relevant species in clinical diagnostics, using smaller sample volumes is a major challenge. Herein, the potential of the electroplated nanomaterials towards biomedical sensing and diagnostics is summarized. The key factors affecting the surface functionality, dimensionality, S/N ratio and analytical response of the prepared chips are highlighted. Furthermore, the application of electroplated chips as a fast “read out” platform for profiling of clinical samples was demonstrated. Full article
Open AccessProceedings Ultrathin Amorphous Carbon as Active Part of Vibrating MEMS
Proceedings 2018, 2(13), 818; https://doi.org/10.3390/proceedings2130818
Published: 4 December 2018
Viewed by 77 | PDF Full-text (831 KB)
Abstract
Amorphous carbon in ultra-thin thicknesses shows amazing mechanical properties that make it particularly interesting for MEMS, especially as a vibrating membrane. We present the experimental results obtained on devices comprising composite membranes of a few nanometers thick suspended above cavities of 1 to
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Amorphous carbon in ultra-thin thicknesses shows amazing mechanical properties that make it particularly interesting for MEMS, especially as a vibrating membrane. We present the experimental results obtained on devices comprising composite membranes of a few nanometers thick suspended above cavities of 1 to 2 μm in width. The behaviors in quasi-static mode—at low frequency—and also in resonant mode were observed and measured. Resonances frequencies of 20 MHz to 110MHz depending on the geometry were measured. Full article
Open AccessProceedings Development of a Point-of-Care Platform for Plant Health Assessment: A Microfluidic Approach
Proceedings 2018, 2(13), 819; https://doi.org/10.3390/proceedings2130819 (registering DOI)
Published: 13 December 2018
PDF Full-text (591 KB)
Abstract
Azelaic Acid (AzA) is a signaling molecule that plays a role in plant immune response when these are infected with pathogens, such as Botryitis cinerea, making its early detection in the field critical in the monitoring and prevention of large spread infection in
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Azelaic Acid (AzA) is a signaling molecule that plays a role in plant immune response when these are infected with pathogens, such as Botryitis cinerea, making its early detection in the field critical in the monitoring and prevention of large spread infection in crops. In this work, a microfluidic platform for the rapid detection of AzA in grapes is presented. AzA detection is achieved via an enzyme-enabled colorimetric reaction performed in a microfluidic chip coupled to a thin-film silicon photodiode. The detection of nM concentrations of AzA in buffer was achieved and initial results for AzA measurements in artificially spiked grape juice show potential for detection in realistic sample conditions. Full article
Open AccessProceedings How the Chamber Design Can Affect Gas Sensor Responses
Proceedings 2018, 2(13), 820; https://doi.org/10.3390/proceedings2130820
Published: 30 November 2018
Viewed by 95 | PDF Full-text (610 KB)
Abstract
In this paper, we report the significant role played by the testing chamber for measuring the true gas sensor responses. Two different designs were studied and compared. The first one has a cross-shape in which the direction of gas flow is perpendicular to
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In this paper, we report the significant role played by the testing chamber for measuring the true gas sensor responses. Two different designs were studied and compared. The first one has a cross-shape in which the direction of gas flow is perpendicular to the sensor surface. The second one has a boat-shape in which the gas flow is tangential to the sensor surface. The results demonstrated that contrarily to the cross-shape chamber, the gas concentration is highly homogenous and equal to the set point in the boat-shape chamber. Additionally, the sensor responses are much stable, faster and higher. Besides, all the mathematical modeling and simulation results are in a good agreement with the experimental studies, which allow the validation of the proposed boat-shape chamber model. Full article
Open AccessProceedings Modular Ceramic-Polymeric Device for Analysis of Selected Elements in Liquid Using Microplasma
Proceedings 2018, 2(13), 822; https://doi.org/10.3390/proceedings2130822
Published: 10 December 2018
PDF Full-text (570 KB)
Abstract
Miniaturization of devices for analysis of chemical composition is being still developed. In this article we present a portable device with a microplasma excitation source. The microdischarge is ignited inside a ceramic structure between a solid anode and a liquid cathode. As a
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Miniaturization of devices for analysis of chemical composition is being still developed. In this article we present a portable device with a microplasma excitation source. The microdischarge is ignited inside a ceramic structure between a solid anode and a liquid cathode. As a result of cathode sputtering of the solution, it is possible to determine its chemical specimens by analysis of emission spectra of the microdischarge. We fabricated cathodes with a microfluidic compartment and two types of anodes. Devices were tested experimentally. Spectroscopic properties of the microdischarge and its analytical performance depended on the used ceramic structure, the surface area of the cathode aperture and the flow rate of the solution. Full article
Open AccessProceedings Comparative Studies of Chemoresistive Gas Sensors Based on Multiple Randomly Connected Wires and Arrays of Single-Wires
Proceedings 2018, 2(13), 823; https://doi.org/10.3390/proceedings2130823
Published: 4 December 2018
Viewed by 86 | PDF Full-text (607 KB)
Abstract
Chemoresitive gas sensors based on multiple nanowires (M-NWs) randomly grown and electrically inter-connected on the top of interdigitated electrodes (IDEs) and arrays of single nanowires connected between faced nanoelectrodes (A-S-NWs) are developed in this work. These systems, consisting of gas sensitive tungsten oxide
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Chemoresitive gas sensors based on multiple nanowires (M-NWs) randomly grown and electrically inter-connected on the top of interdigitated electrodes (IDEs) and arrays of single nanowires connected between faced nanoelectrodes (A-S-NWs) are developed in this work. These systems, consisting of gas sensitive tungsten oxide nanowires (NWs), are tested to NO2, and their performance regarding the response magnitude, sensitivity and response rate are evaluated here. Full article
Open AccessProceedings Ion-Selective Optical Sensors: A New Look at Well-Established Techniques of Signal Acquisition
Proceedings 2018, 2(13), 825; https://doi.org/10.3390/proceedings2130825
Published: 7 December 2018
PDF Full-text (750 KB)
Abstract
It is demonstrated for the first time that the registration of the optode signal under non-equilibrium conditions reduces analysis time and shifts the sensor working range. The fabrication of optode-like color standards for digital color analysis (DCA) is described, and a multi-parameter color
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It is demonstrated for the first time that the registration of the optode signal under non-equilibrium conditions reduces analysis time and shifts the sensor working range. The fabrication of optode-like color standards for digital color analysis (DCA) is described, and a multi-parameter color scale for calibration-free sensor arrays is proposed. Advantages and limitations of monochrome and color camera for DCA with colorimetric optodes are discussed. Full article
Open AccessProceedings Screen-Printed f-EM Sensors Based on Two Chelating-Polymers and a Metal Oxide for the Continuous Detection of Cu Ions in Surface Water
Proceedings 2018, 2(13), 828; https://doi.org/10.3390/proceedings2130828
Published: 7 December 2018
PDF Full-text (789 KB)
Abstract
Pollutants affect water worldwide and consequently present a risk to both the environment and to human health. Cu is an essential element for many organisms, but becomes toxic at relatively high concentrations. Current laboratory-based methods are not able to monitor water quality continuously,
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Pollutants affect water worldwide and consequently present a risk to both the environment and to human health. Cu is an essential element for many organisms, but becomes toxic at relatively high concentrations. Current laboratory-based methods are not able to monitor water quality continuously, as they require laborious sampling and offline monitoring. A potential method that is capable to addressing this problem, guaranteeing the continuous monitoring of water resources, is the integration of microwave spectroscopy with functionalised electromagnetic (f-EM) sensors. The feasibility of using this combined method for achieving a more specific response toward low concentrations of Cu has been demonstrated. Full article
Open AccessProceedings Efficient Self-Heating in Nanowire Sensors: Prospects for Very-Low Power
Proceedings 2018, 2(13), 829; https://doi.org/10.3390/proceedings2130829
Published: 11 December 2018
PDF Full-text (915 KB)
Abstract
Self-heating operation, or the use of the resistance-probing signal to warm up and control the temperature of nanowire devices, has been the subject of research for more than a decade. The state-of-the-art shows that this approach is serving to lower the power demand
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Self-heating operation, or the use of the resistance-probing signal to warm up and control the temperature of nanowire devices, has been the subject of research for more than a decade. The state-of-the-art shows that this approach is serving to lower the power demand in temperature-activated devices, especially in conductometric gas sensors, but the simplicity of eliminating the heating element comes with the complexity of integrating 1-dimensional nanomaterials in electronic devices. The advantages of the efficient self-heating effect in nanowires have already been probed in a broad range of systems and materials. But when it comes to transfer this operating principle to new systems and materials natural doubts arise: how to do it?, how much savings in power will be achieved? We will address these questions in this review contribution. Full article
Open AccessProceedings Modeling Planar Fluxgate Structures
Proceedings 2018, 2(13), 830; https://doi.org/10.3390/proceedings2130830
Published: 10 December 2018
PDF Full-text (443 KB)
Abstract
Planar fluxgate structures have been the focus of multiple experimental studies. However, theoretical treatises are still limited to the classical models that describe 3D structures. In this paper we derive an effective fluxgate equation for planar systems, dealing with strong stray fields and
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Planar fluxgate structures have been the focus of multiple experimental studies. However, theoretical treatises are still limited to the classical models that describe 3D structures. In this paper we derive an effective fluxgate equation for planar systems, dealing with strong stray fields and direct coupling, and show the stability and applicability of the Vacquier implementation. To support the theoretical model, FEM simulations are performed that also provide means of layouting planar fluxgates by pure magnetostatic simulation. Full article
Open AccessProceedings Analysis of Single- and Double Core Planar Fluxgate Structures
Proceedings 2018, 2(13), 831; https://doi.org/10.3390/proceedings2130831
Published: 10 December 2018
PDF Full-text (723 KB)
Abstract
The planar fluxgate is an emerging technology feasible for system integration contrary to it’s bulky 3D counterpart. Recently, a novel structure based on an asymmetric double core layout for improved sensitivity and energy efficiency was proposed. The aim of this paper is, for
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The planar fluxgate is an emerging technology feasible for system integration contrary to it’s bulky 3D counterpart. Recently, a novel structure based on an asymmetric double core layout for improved sensitivity and energy efficiency was proposed. The aim of this paper is, for the first time, to conduct a direct experimental comparison between single- and asymmetric double-core structures. The results confirm the original conjecture and show that asymmetric double core structures can easily boost the sensitivity by a factor of two for similar power supply. Full article
Open AccessProceedings Finite Element Method Simulation and Characterization of a Thermal Flow Sensor Based on Printed Circuit Board Technology for Various Fluids
Proceedings 2018, 2(13), 833; https://doi.org/10.3390/proceedings2130833
Published: 3 December 2018
Viewed by 126 | PDF Full-text (859 KB)
Abstract
We present finite element method (FEM) simulations of a thermal flow sensor as well as a comparison to measurement results. The thermal sensor is purely based on printed circuit board (PCB) technology, designed for heating, ventilation, and air conditioning (HVAC) systems. Design and
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We present finite element method (FEM) simulations of a thermal flow sensor as well as a comparison to measurement results. The thermal sensor is purely based on printed circuit board (PCB) technology, designed for heating, ventilation, and air conditioning (HVAC) systems. Design and readout method of the sensor enables the possibility to measure the flow velocity in various fluids. 2D-FEM simulations were carried out in order to predict the sensor characteristic of envisaged setups. The simulations enable a fast and easy way to evaluate the sensor’s behaviour in different fluids. The results of the FEM simulations are compared to measurements in a real environment, proving the credibility of the model. Full article
Open AccessProceedings Visible Light Activated Room Temperature Gas Sensors Based on CaFe2O4 Nanopowders
Proceedings 2018, 2(13), 834; https://doi.org/10.3390/proceedings2130834
Published: 4 December 2018
Viewed by 91 | PDF Full-text (553 KB)
Abstract
Gas sensors based on CaFe2O4 nanopowders, which are p–type metal oxide semiconductor (MOX), have been fabricated and assessed for ethanol gas monitoring under visible light activation at room temperature. Regardless of their inferior sensitivity compared to thermally activated counterparts, the
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Gas sensors based on CaFe2O4 nanopowders, which are p–type metal oxide semiconductor (MOX), have been fabricated and assessed for ethanol gas monitoring under visible light activation at room temperature. Regardless of their inferior sensitivity compared to thermally activated counterparts, the developed sensors have shown responsive sensing behavior towards ethanol vapors confirming the ability of using visible light for sensor activation. LEDs with different wavelengths (i.e., 465–590 nm) were employed. The highest sensitivity (3.7%) was reached using green LED activation that corresponds to the band gap of CaFe2O4. Full article
Open AccessProceedings W-Sn Mixed Oxides and ZnO to Detect NOx and Ozone in Atmosphere
Proceedings 2018, 2(13), 836; https://doi.org/10.3390/proceedings2130836
Published: 4 December 2018
Viewed by 76 | PDF Full-text (1130 KB)
Abstract
Thick films of zinc oxide (ZnO) in form of nanospheres or hexagonal prisms and of tungsten-tin (W-Sn) mixed oxides at nominal Sn molar fraction (0.1, 0.3 and 0.5) were prepared. The functional materials were synthesized and characterized by SEM and TEM, X-ray diffraction,
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Thick films of zinc oxide (ZnO) in form of nanospheres or hexagonal prisms and of tungsten-tin (W-Sn) mixed oxides at nominal Sn molar fraction (0.1, 0.3 and 0.5) were prepared. The functional materials were synthesized and characterized by SEM and TEM, X-ray diffraction, specific surface area measurements, UV-Vis-NIR and IR spectroscopies. The gas sensing measurements highlighted that ZnO is more performant in form of nanoprisms, while W-Sn sensors offer a better response towards NOx and ozone with respect to pure WO3. Full article
Open AccessProceedings MEMS Enabled Bendable and Stretchable Silicon Circuits
Proceedings 2018, 2(13), 837; https://doi.org/10.3390/proceedings2130837
Published: 4 December 2018
Viewed by 90 | PDF Full-text (2404 KB)
Abstract
We report the design and implementation of a unique, wafer sized stretchable and bendable monolithic silicon matrix structure. The achieved stretchability allows for simultaneous omnidirectional folding, required to conform the structure to complex curved 3D surfaces. Moreover, it also enables dynamic mechanical deformation
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We report the design and implementation of a unique, wafer sized stretchable and bendable monolithic silicon matrix structure. The achieved stretchability allows for simultaneous omnidirectional folding, required to conform the structure to complex curved 3D surfaces. Moreover, it also enables dynamic mechanical deformation of the structure to cope with a moving environment, like e.g., the wall of the heart muscle. Due to the nature of the fabrication process, normal silicon wafer processing can be performed prior to rendering it stretchable. This is first demonstrated by the fabrication of two metal layers on top of silicon, which act as the electrical interconnects of a final flexible and stretchable LED-matrix. Currently, the possibility to postprocess an existing commercial CMOS process is investigated. This would lead to a revolutionary potential of new applications, especially in the medical field, by enabling complex silicon monitoring systems to be linked to organs without hindering them. Full article
Open AccessProceedings Analytical Modelling of Magnetic Multimedia Control Elements Based on a Single Magnetic Sensor
Proceedings 2018, 2(13), 840; https://doi.org/10.3390/proceedings2130840
Published: 4 December 2018
Viewed by 92 | PDF Full-text (611 KB)
Abstract
Magnetic multimedia control elements have many advantages in comparison with other systems based on mechanical, electrical, or optical readout. For system layouting, the practicality of analytical models over extensive numerical simulation was demonstrated in the past. In this work, we apply the analytical
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Magnetic multimedia control elements have many advantages in comparison with other systems based on mechanical, electrical, or optical readout. For system layouting, the practicality of analytical models over extensive numerical simulation was demonstrated in the past. In this work, we apply the analytical approach to design magnetic multimedia control elements. Particularly, we focus on a joystick that includes only a single 3D magnetic sensor and can be used in continuous operating mode. Presented results relate to a system based on a single permanent magnet and a single 3D sensor. The scheme was used to build a prototype to perform prove of principle experiments. A semi-analytic method to determine positions of the joystick from the observed magnetic field is discussed. Full article
Open AccessProceedings Mixed Cerium/Zirconium Oxide as a Material for Carbon Monoxide Thermocatalytic Gas Sensor
Proceedings 2018, 2(13), 841; https://doi.org/10.3390/proceedings2130841
Published: 4 December 2018
Viewed by 76 | PDF Full-text (383 KB)
Abstract
The perspective catalysts usable for the fabrication of thermocatalytic gas sensors were studied. The analysis of CO oxidation kinetics by Pd decorated Al2O3, ZSM-5, SnO2, CeO2/ZrO2 and some other carriers of catalysts showed that
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The perspective catalysts usable for the fabrication of thermocatalytic gas sensors were studied. The analysis of CO oxidation kinetics by Pd decorated Al2O3, ZSM-5, SnO2, CeO2/ZrO2 and some other carriers of catalysts showed that the application of these catalysts leads to the ambiguity of sensor response (light-off effect). It was demonstrated that a catalyst based on CeO2/ZrO2 carrier could be used for the fabrication of sensors characterized by the univocal correspondence between CO concentration and sensor response. The developed model of the CO oxidation on all Pd catalysts with inert carrier enabled the description of the CO oxidation using a single value of activation energy. Full article
Open AccessProceedings Contactless Readout of Passive LC Sensors with Compensation Circuit for Distance-Independent Measurements
Proceedings 2018, 2(13), 842; https://doi.org/10.3390/proceedings2130842
Published: 3 December 2018
Viewed by 79 | PDF Full-text (1408 KB)
Abstract
Contactless readout of passive LC sensors composed of a capacitance sensor connected to a coil can be performed through an electromagnetically coupled readout coil set at distance d. Resonant frequency fs and Q-factor QS of the LC sensor can be
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Contactless readout of passive LC sensors composed of a capacitance sensor connected to a coil can be performed through an electromagnetically coupled readout coil set at distance d. Resonant frequency fs and Q-factor QS of the LC sensor can be extracted from the measurement of the impedance at the readout coil by using a technique theoretically independent of d. This work investigates the effects on the measurement accuracy due to the unavoidable parasitic capacitance CP in parallel to the readout coil, which makes the measured values of fs and QS dependent on d. Numerical analysis and experimental tests confirm such dependence. To overcome this limitation, a novel electronic circuit topology for the compensation of CP is proposed. The experimental results on assembled prototypes show that for a LC sensor with fs ≈ 5.48 MHz a variation of less than 200 ppm across an interrogation distance between 2 and 18 mm is achieved with the proposed compensation circuit. Full article
Open AccessProceedings Responsitivity Measurement of a Lorentz Force Transducer for Homogeneous and Inhomogeneous Magnetic Fields
Proceedings 2018, 2(13), 843; https://doi.org/10.3390/proceedings2130843
Published: 3 December 2018
Viewed by 61 | PDF Full-text (949 KB)
Abstract
This paper reports a MEMS gradiometer consisting of two independent, laterally oscillating masses on a single chip with integrated optical readout featuring a responsitivity of 35V/T at resonant operation. The symmetrical design of the two masses offers high accuracy and low cost by
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This paper reports a MEMS gradiometer consisting of two independent, laterally oscillating masses on a single chip with integrated optical readout featuring a responsitivity of 35V/T at resonant operation. The symmetrical design of the two masses offers high accuracy and low cost by using conventional MEMS batch fabrication technology. The sensing principle is based on lateral displacement of the masses actuated by Lorentz forces which modulates a light flux passing through a stationary mask and the moving mask integrated in the masses. Phase and intensity detected by photodiodes reveal information about the uniformity of an external applied magnetic field, hence, enables the measurement of gradient-, homogeneous- and offset gradient magnetic fields. Full article
Open AccessProceedings Influence of the Geometry on the LTCC Integrated Electrochemical Cells Performance
Proceedings 2018, 2(13), 844; https://doi.org/10.3390/proceedings2130844
Published: 3 December 2018
Viewed by 74 | PDF Full-text (394 KB)
Abstract
Miniaturized and integrated analytical devices, including chemical sensors, are at the forefront of modern analytical chemistry. The construction of novel analytical tools takes advantage of contemporary micro- and nanotechnologies, as well as materials science and technology. The goal of this study was investigate
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Miniaturized and integrated analytical devices, including chemical sensors, are at the forefront of modern analytical chemistry. The construction of novel analytical tools takes advantage of contemporary micro- and nanotechnologies, as well as materials science and technology. The goal of this study was investigate electron transfer resistance in model solution and protein adsorption using integrated electrochemical cell with different geometry. Full article
Open AccessProceedings Top-Down Fabrication of Arrays of Vertical GaN Nanorods with Freestanding Top Contacts for Environmental Exposure
Proceedings 2018, 2(13), 845; https://doi.org/10.3390/proceedings2130845
Published: 3 December 2018
Viewed by 89 | PDF Full-text (569 KB)
Abstract
Arrays of 1D-vertically arranged gallium nitride (GaN) nanorods (NRs) are fabricated on sapphire and connected to both bottom and freestanding top contacts. This shows a fully validated top-down method to obtain ordered arrays of high-surface-to-volume elements that can be electrically interrogated and used,
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Arrays of 1D-vertically arranged gallium nitride (GaN) nanorods (NRs) are fabricated on sapphire and connected to both bottom and freestanding top contacts. This shows a fully validated top-down method to obtain ordered arrays of high-surface-to-volume elements that can be electrically interrogated and used, e.g., for sensing applications. Specifically, these will be used as highly integrated heating elements for conductometric gas sensors in self-heating operation. Detailed fabrication and processing steps involving inductively coupled plasma reactive ion etching (ICP-RIE), KOH-etching, interspace filling, and electron-beam physical vapor deposition technologies are discussed, in which they can be well adjusted and combined to obtain vertical GaN NRs as thin as 300 nm in arbitrarily large and regular arrays (e.g., 1 × 1, 3 × 3, 9 × 10 elements). These developed devices are proposed as a novel sensor platform for temperature-activated measurements that can be produced at a large scale offering low-power, and very stable temperature control. Full article
Open AccessProceedings Gas-Flow Sensor Based on Self-Oscillating and Self-Sensing Cantilever
Proceedings 2018, 2(13), 846; https://doi.org/10.3390/proceedings2130846
Published: 3 December 2018
Viewed by 74 | PDF Full-text (531 KB)
Abstract
In this work the application of a self-sensing and self-actuating cantilever for gas-flow measurement is investigated. The cantilever placed in the flow is excited permanently at its first resonance mode. Simultaneously the resonance amplitude, the resonance frequency and the static bending of the
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In this work the application of a self-sensing and self-actuating cantilever for gas-flow measurement is investigated. The cantilever placed in the flow is excited permanently at its first resonance mode. Simultaneously the resonance amplitude, the resonance frequency and the static bending of the cantilever are detected. All three sizes are related to the velocity of the gas-flow. Full article
Open AccessProceedings Apta- and Immuno-Sensors Performance Optimization: A Comparative Study of Surface Functionalization Techniques
Proceedings 2018, 2(13), 847; https://doi.org/10.3390/proceedings2130847
Published: 11 December 2018
PDF Full-text (305 KB)
Abstract
Surface bio-functionalization plays a critical role in the performance of a biosensor and numerous techniques for the enhancement of a biosensor’s surface coverage with oriented capture biomolecules have been developed with the ultimate goal of optimizing a sensor’s performance in terms of its
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Surface bio-functionalization plays a critical role in the performance of a biosensor and numerous techniques for the enhancement of a biosensor’s surface coverage with oriented capture biomolecules have been developed with the ultimate goal of optimizing a sensor’s performance in terms of its sensitivity and linear response over a wide dynamic range. Herein, highlights of a comparative assessment into the most promising approaches to achieve this goal are being presented. For aptamer-modified surfaces, polyamidoamine (PAMAM) dendrimers and polysaccharide networks were employed with the obtained results clearly indicating that a much denser surface coverage with aptamers can be achieved with the use of the latter. For the functionalization of surfaces with antibodies, the orientation and density of immobilized antibodies onto recombinant protein A/G- or boronic acid-modified substrates were compared, with the former leading not only to increased antibody loading but also with such an orientation that permits enhanced antigen binding. The conclusions reached can be used as a starting point for the customization of sensor functionalization in a plethora of clinical, environmental and even food-industry-related biosensing platforms. Full article
Open AccessProceedings Clamping and Q-Factor Improvement in a Carbon Nanotube Resonator
Proceedings 2018, 2(13), 848; https://doi.org/10.3390/proceedings2130848
Published: 3 December 2018
Viewed by 109 | PDF Full-text (1479 KB)
Abstract
This work reports the clamping effects on the performance of a carbon nanotube based
nanoresonator. A direct comparison of two different nanotube-clamping geometries on the same
nanotube device is presented. The nanotube was mechanically dry transferred and clamped through
van-der-Waals forces onto palladium
[...] Read more.
This work reports the clamping effects on the performance of a carbon nanotube based
nanoresonator. A direct comparison of two different nanotube-clamping geometries on the same
nanotube device is presented. The nanotube was mechanically dry transferred and clamped through
van-der-Waals forces onto palladium electrodes resulting in a bottom clamped configuration. A 20
nm platinum layer was then selectively deposited on the electrodes through atomic layer
deposition resulting in top-bottom clamped configuration. With top clamping, a Q-factor increase
of 1.5~2× has been observed accompanied by a decrease in the resonance frequency. Full article
Open AccessProceedings Porous Polymer Based Flexible Pressure Sensors for Medical Applications
Proceedings 2018, 2(13), 849; https://doi.org/10.3390/proceedings2130849
Published: 4 December 2018
Viewed by 80 | PDF Full-text (774 KB)
Abstract
This paper focuses on the use of microporous PDMS foams as a highly deformable film to improve the sensitivity of flexible capacitive pressure sensor dedicated to wearable use. A fabrication process allowing the mechanical properties of foams to be adjusted is proposed together
[...] Read more.
This paper focuses on the use of microporous PDMS foams as a highly deformable film to improve the sensitivity of flexible capacitive pressure sensor dedicated to wearable use. A fabrication process allowing the mechanical properties of foams to be adjusted is proposed together with a non-linear behavioral model used to objectively estimate the sensor performances in terms of sensitivity and measurement range. Sensors fabricated and characterized in this study show that the sensitivity and the measurement range can be adjusted from 0.14%/kPa up to 13.07%/kPa, and from 594 kPa to 183 kPa, respectively, while the PDMS film porosity ranges from 0% up to 85%. Full article
Open AccessProceedings Estimation of the Particle Sizing Error Due to Particle Position in an Integrated PM2.5 Optical Particle Counter
Proceedings 2018, 2(13), 850; https://doi.org/10.3390/proceedings2130850
Published: 4 December 2018
Viewed by 77 | PDF Full-text (626 KB)
Abstract
An increasing need for portable personal time- and size-resolved monitoring of the fine airborne particulate matter drives the development towards miniaturization and cost reduction of the optical particle counters. In an integrated design of the optical particle counters, the confinement of the air
[...] Read more.
An increasing need for portable personal time- and size-resolved monitoring of the fine airborne particulate matter drives the development towards miniaturization and cost reduction of the optical particle counters. In an integrated design of the optical particle counters, the confinement of the air is becoming more critical, since variations in particle positions are getting bigger relative to the dimensions of the sensor. Variations in particle position directly affect the light collection angle and hence induce the particle sizing error. We have developed a 3D simulation framework based on a Lorentz-Mie theory and analyzed the effect of particle position on the particle sizing error. We show that the relative sizing error induced by particle position is detrimental and seriously limits the sizing performance of downscaled PM2.5 sensors. Full article
Open AccessProceedings Review of LiDAR Sensor Data Acquisition and Compression for Automotive Applications
Proceedings 2018, 2(13), 852; https://doi.org/10.3390/proceedings2130852
Published: 6 December 2018
Viewed by 93 | PDF Full-text (236 KB)
Abstract
Due to specific dynamics of the operating environment and required safety regulations, the amount of acquired data of an automotive LiDAR sensor that has to be processed is reaching several Gbit/s. Therefore, data compression is much-needed to enable future multi-sensor automated vehicles. Numerous
[...] Read more.
Due to specific dynamics of the operating environment and required safety regulations, the amount of acquired data of an automotive LiDAR sensor that has to be processed is reaching several Gbit/s. Therefore, data compression is much-needed to enable future multi-sensor automated vehicles. Numerous techniques have been developed to compress LiDAR raw data; however, these techniques are primarily targeting a compression of 3D point cloud, while the way data is captured and transferred from a sensor to an electronic computing unit (ECU) was left out. The purpose of this paper is to discuss and evaluate how various low-level compression algorithms could be used in the automotive LiDAR sensor in order to optimize on-chip storage capacity and link bandwidth. We also discuss relevant parameters that affect amount of collected data per second and what are the associated issues. After analyzing compressing approaches and identifying their limitations, we conclude several promising directions for future research. Full article
Open AccessProceedings Simulation and Performance Optimization of an Amperometric Histamine Detection System
Proceedings 2018, 2(13), 853; https://doi.org/10.3390/proceedings2130853
Published: 20 November 2018
Viewed by 119 | PDF Full-text (692 KB)
Abstract
One of the most widely known biogenic amines is histamine, which plays an important role in the human immune system. Some people suffer from allergic reactions after a histamine-rich diet; this is called histamine intolerance. The aim of this work is to develop
[...] Read more.
One of the most widely known biogenic amines is histamine, which plays an important role in the human immune system. Some people suffer from allergic reactions after a histamine-rich diet; this is called histamine intolerance. The aim of this work is to develop a quick and reliable method for the detection and quantification of histamine in food, based on an electrochemical approach. In presence of biogenic amines, a reduction cascade induces a current at the working electrode. Prior to chronoamperometric measurements, Finite Elemente simulations were performed. The results are presented in this work. Full article
Open AccessProceedings Highly Sensitive NH3 Sensors Using CVD and Epitaxial Graphene Functionalised with Vanadium(V) Oxide: A Comparative Study
Proceedings 2018, 2(13), 854; https://doi.org/10.3390/proceedings2130854
Published: 20 November 2018
Viewed by 108 | PDF Full-text (560 KB)
Abstract
Exceptionally sensitive and selective graphene-based chemiresistive gas sensors were produced as a result of graphene functionalisation with a sub-nanometer V2O5 layer by using the method of pulsed laser deposition. Two different types of graphene were used—epitaxial graphene on SiC and
[...] Read more.
Exceptionally sensitive and selective graphene-based chemiresistive gas sensors were produced as a result of graphene functionalisation with a sub-nanometer V2O5 layer by using the method of pulsed laser deposition. Two different types of graphene were used—epitaxial graphene on SiC and CVD graphene on Si/SiO2—and both showed remarkable enhancement of sensing properties in terms of response and recovery speed, response magnitude and selectiveness towards NH3 gas. The epitaxial graphene-based sensor was demonstrating the highest relative response towards ammonia amounting to 80% for 0.1 ppm NH3. Full article
Open AccessProceedings Characterization of a Micro-Opto-Mechanical Transducer for the Electric Field Strength
Proceedings 2018, 2(13), 855; https://doi.org/10.3390/proceedings2130855
Published: 21 November 2018
Viewed by 120 | PDF Full-text (1505 KB)
Abstract
We report on a new optical sensing principle for measuring the electric field strength based on MEMS technology. This method allows for distortion-free and point-like measurements with high stability regarding temperature. The main focus of this paper rests on an enhanced measurement set-up
[...] Read more.
We report on a new optical sensing principle for measuring the electric field strength based on MEMS technology. This method allows for distortion-free and point-like measurements with high stability regarding temperature. The main focus of this paper rests on an enhanced measurement set-up and the thereby obtained measurement results. These results reveal an improved resolution limit and point to the limitations of the current characterization approach. A resolution limit of 222 V/m was achieved while a further improvement of roughly one order of magnitude is feasible. Full article
Open AccessProceedings Artificial Landmarks for Autonomous Vehicles Based on Magnetic Sensors
Proceedings 2018, 2(13), 856; https://doi.org/10.3390/proceedings2130856
Published: 20 November 2018
Viewed by 133 | PDF Full-text (321 KB)
Abstract
We propose to use an integration process based on Transducer Electronic Data Sheets applied to a magnetic sensor system for the realization of artificial landmarks. Magnetic sensors provide an advantageous alternative in surroundings where GPS and optical sensors do not work. These landmarks
[...] Read more.
We propose to use an integration process based on Transducer Electronic Data Sheets applied to a magnetic sensor system for the realization of artificial landmarks. Magnetic sensors provide an advantageous alternative in surroundings where GPS and optical sensors do not work. These landmarks can be used by passing autonomous vehicles, e.g., drones, for re-orientation and re-calibration. To facilitate the usage of these landmarks also by any vehicle, known or unknown, a standardized process for automatic connection and identification of the landmarks is suggested. During this process, all necessary information such as protocols, calibration data etc. is made known to the vehicle passing by. Based on the provided information, the vehicle itself can decide whether and how to use the provided sensory information. Full article
Open AccessProceedings Optimized Polyvinylidene Fluoride Nanofiber Webs for Flexible Energy Harvesters
Proceedings 2018, 2(13), 857; https://doi.org/10.3390/proceedings2130857
Published: 20 November 2018
Viewed by 123 | PDF Full-text (743 KB)
Abstract
This work reports the process optimization of various electrospinning parameters to fabricate polyvinylidene fluoride based piezoelectric flexible nanofiber webs for passive sensing and energy harvesting applications. Process parameters like electrospinning voltage and drum speed have been taken into consideration while optimizing the electrospun
[...] Read more.
This work reports the process optimization of various electrospinning parameters to fabricate polyvinylidene fluoride based piezoelectric flexible nanofiber webs for passive sensing and energy harvesting applications. Process parameters like electrospinning voltage and drum speed have been taken into consideration while optimizing the electrospun nanofiber webs for maximizing their piezoelectric property. Finally, the optimized recipe is used to fabricate a flexible PVDF nanofiber energy harvester to demonstrate the energy harvesting capability of such nanofiber webs. Full article
Open AccessProceedings Thermal Modulation of a High-Bandwidth Gas Sensor Array in Real-Time for Application on a Mobile Robot
Proceedings 2018, 2(13), 858; https://doi.org/10.3390/proceedings2130858
Published: 20 November 2018
Viewed by 116 | PDF Full-text (805 KB)
Abstract
A new signal processing technique has been developed for resistive metal oxide (MOX) gas sensors to enable high-bandwidth measurements and enhanced selectivity at PPM levels (<50 PPM VOCs). An embedded micro-heater is thermally pulsed from 225 to 350 °C, which enables the chemical
[...] Read more.
A new signal processing technique has been developed for resistive metal oxide (MOX) gas sensors to enable high-bandwidth measurements and enhanced selectivity at PPM levels (<50 PPM VOCs). An embedded micro-heater is thermally pulsed from 225 to 350 °C, which enables the chemical reactions in the sensor film (e.g., SnO2, WO3, NiO) to be extracted using a fast Fourier transform. Signal processing is performed in real-time using a low-cost microcontroller integrated into a sensor module. The approach enables the remove of baseline drift and is resilient to environmental temperature changes. Bench-top experimental results are presented for 50 to 200 ppm of ethanol and CO, which demonstrate our sensor system can be used within a mobile robot. Full article
Open AccessProceedings Fog Effects on Time-of-Flight Imaging Investigated by Ray-Tracing Simulations
Proceedings 2018, 2(13), 859; https://doi.org/10.3390/proceedings2130859
Published: 29 November 2018
Viewed by 99 | PDF Full-text (900 KB)
Abstract
Time-of-Flight (ToF) sensors are a key technology for autonomous vehicles and autonomous mobile robotics. Quantifying the extent of perturbation induced by atmospheric phenomena on ToF imaging is critical to identify effective correction strategies. Here we present an approach that uses optical ray-tracing to
[...] Read more.
Time-of-Flight (ToF) sensors are a key technology for autonomous vehicles and autonomous mobile robotics. Quantifying the extent of perturbation induced by atmospheric phenomena on ToF imaging is critical to identify effective correction strategies. Here we present an approach that uses optical ray-tracing to simulate the ToF image, while the distance information is recovered by analyzing the optical path of each ray. Such an approach allows, for example, understanding the effects of different ray paths on the ToF image, or testing various retrieval/correction algorithms upon running a single ray-tracing simulation. By modelling several scattering scenarios, we show that ranging errors arise mostly from light backscattered to the sensor prior reaching the scene. Scattering events close to the sensors (<1 m) have the largest influence, therefore strategies capable of filtering out signals from distances shorter than the range of interest can significantly improve the accuracy of ToF sensors. Full article
Open AccessProceedings Sensorized Insole for Diabetic Foot Monitoring
Proceedings 2018, 2(13), 860; https://doi.org/10.3390/proceedings2130860
Published: 26 November 2018
Viewed by 113 | PDF Full-text (559 KB)
Abstract
Several wearable technologies for the prevention of diabetic foot ulcers have been developed by the scientific community. However, they are often very invasive and normally just one parameter between pressure loads or temperature is acquired. Moreover the amount of thermal reading points is
[...] Read more.
Several wearable technologies for the prevention of diabetic foot ulcers have been developed by the scientific community. However, they are often very invasive and normally just one parameter between pressure loads or temperature is acquired. Moreover the amount of thermal reading points is lower than 5 and the accuracy of thermal sensors is greater than 0.5 °C. This work presents a low invasive and accurate smart insole in which both temperature and pressure data are acquired in 8 reading points and then transmitted to a gateway, through a wireless protocol, in order to communicate the foot health status to the caregiver. Full article
Open AccessProceedings 3D Printed Capacitive Fluid Level Sensor
Proceedings 2018, 2(13), 861; https://doi.org/10.3390/proceedings2130861
Published: 21 November 2018
Viewed by 132 | PDF Full-text (485 KB)
Abstract
A three dimensional, additively manufactured interdigital capacitive sensor for fluid level measurement applications is introduced. The device was fabricated using the fused filament fabrication (FFF) additive manufacturing (AM) process and an off the shelf conductive filament with a volume resistivity ρ = 0.6
[...] Read more.
A three dimensional, additively manufactured interdigital capacitive sensor for fluid level measurement applications is introduced. The device was fabricated using the fused filament fabrication (FFF) additive manufacturing (AM) process and an off the shelf conductive filament with a volume resistivity ρ = 0.6 Ω cm. The 3D fabrication process allows great flexibility in terms of sensor ̇ design and an increase of the surface area between the electrodes, compensating the relatively large plate separation and yielding a high sensitivity to increasing fluid levels. The measurements presented in this abstract show the average increase of capacitance in response to an incrementally increasing volume of de-ionized water (DI-water) filled between the separate digits. Full article
Open AccessProceedings Flexible Simulation Platform for Multilayer Piezoelectric MEMS Microphones with Signal-to-Noise Ratio (SNR) Evaluation
Proceedings 2018, 2(13), 862; https://doi.org/10.3390/proceedings2130862
Published: 23 November 2018
Viewed by 102 | PDF Full-text (1657 KB)
Abstract
A flexible simulation platform to design new piezoelectric MEMS (micro-electro-mechanical systems) microphones with signal-to-noise ratio (SNR) evaluation is presented. The platform is made of two blocks: a multiphysical FEM model, in order to study the acoustic, mechanical and electrical behavior of the MEMS
[...] Read more.
A flexible simulation platform to design new piezoelectric MEMS (micro-electro-mechanical systems) microphones with signal-to-noise ratio (SNR) evaluation is presented. The platform is made of two blocks: a multiphysical FEM model, in order to study the acoustic, mechanical and electrical behavior of the MEMS structure, and an equivalent electro-mechanical-acoustic lumped-element model, which allows studying the microphone system, i.e. the MEMS-package-ASIC interaction. The platform gives precise estimation of sensitivity and SNR, key parameters of a microphone. Full article
Open AccessProceedings A Compact Robust OWLS System for Biosensing of Multiple Samples
Proceedings 2018, 2(13), 863; https://doi.org/10.3390/proceedings2130863
Published: 28 November 2018
Viewed by 84 | PDF Full-text (745 KB)
Abstract
A compact multichannel and portable OWLS (Optical Waveguide Light Mode Spectroscopy) biosensor will be presented. With a sensitivity of 16.3°/RIU (degrees per refractive index unit) it incorporates on-line reference and high potential for further miniaturization. Full article
Open AccessProceedings Hybrid Photonic Crystal-Surface Plasmon Polariton Waveguiding System for On-Chip Sensing Applications
Proceedings 2018, 2(13), 864; https://doi.org/10.3390/proceedings2130864
Published: 21 November 2018
Viewed by 128 | PDF Full-text (753 KB)
Abstract
In this paper, a hybrid optical guiding system based on low group velocity offered by photonic crystal (PhC) waveguides and vertical confinement as well as high field enhancement of. Surface lasmon polaritons (SPP) is proposed. We show that for efficient sensing, conventional two-dimensional
[...] Read more.
In this paper, a hybrid optical guiding system based on low group velocity offered by photonic crystal (PhC) waveguides and vertical confinement as well as high field enhancement of. Surface lasmon polaritons (SPP) is proposed. We show that for efficient sensing, conventional two-dimensional PhC waveguides with finite height require a high aspect ratio in the order of 30 in order to efficiently confine the guiding mode. The fabrication of devices with such a high aspect ratio is considered too challenging and inefficient for mass production. By combining a PhC waveguide and SPPs, the proposed system efficiently confines the optical mode vertically while benefiting from the lateral confinement enabled by PhC structures. As a result, the required aspect ratio drops to about 4 making the fabrication in large scale feasible. This design provides strong light-matter interaction within small dimensions, which is beneficial for miniaturizing on-chip photonic sensors. Full article
Open AccessProceedings Microwave Oscillator Design for a SRR Based Biosensor Platform
Proceedings 2018, 2(13), 865; https://doi.org/10.3390/proceedings2130865
Published: 21 November 2018
Viewed by 114 | PDF Full-text (565 KB)
Abstract
A sensor for biomedical markers based on a split ring microwave resonator (SRR) was developed. The surface of the microwave resonator is covered with receptors that specifically bind to the target proteins where the local permittivity is changed. The resonator is part of
[...] Read more.
A sensor for biomedical markers based on a split ring microwave resonator (SRR) was developed. The surface of the microwave resonator is covered with receptors that specifically bind to the target proteins where the local permittivity is changed. The resonator is part of a microwave oscillator circuit. Changes in the local permittivity caused by coupling of the target proteins result in a change of oscillator frequency which can be easily and accurate measured with high sensitivity. Full article
Open AccessProceedings Pinhole microLED Array as Point Source Illumination for Miniaturized Lensless Cell Monitoring Systems
Proceedings 2018, 2(13), 866; https://doi.org/10.3390/proceedings2130866
Published: 21 November 2018
Viewed by 153 | PDF Full-text (574 KB)
Abstract
Pinhole‐shaped light‐emitting diode (LED) arrays with dimension ranging from 100 μm down to 5 μm have been developed as point illumination sources. The proposed microLED arrays, which are based on gallium nitride (GaN) technology and emitting in the blue spectral region (λ =
[...] Read more.
Pinhole‐shaped light‐emitting diode (LED) arrays with dimension ranging from 100 μm down to 5 μm have been developed as point illumination sources. The proposed microLED arrays, which are based on gallium nitride (GaN) technology and emitting in the blue spectral region (λ = 465 nm), are integrated into a compact lensless holographic microscope for a non‐invasive, label‐free cell sensing and imaging. From the experimental results using single pinhole LEDs having a diameter of 90 μm, the reconstructed images display better resolution and enhanced image quality compared to those captured using a commercial surface‐mount device (SMD)‐based LED. Full article
Open AccessProceedings Multiparameter Sensor Array for Gas Composition Monitoring
Proceedings 2018, 2(13), 867; https://doi.org/10.3390/proceedings2130867
Published: 3 December 2018
Viewed by 92 | PDF Full-text (1718 KB)
Abstract
In the energy transition from fossil to renewable resources, gas is foreseen to play an important role. However, the composition of the gas is expected to change due to a wider variation of sources. In order to mitigate potential challenges for distributors and
[...] Read more.
In the energy transition from fossil to renewable resources, gas is foreseen to play an important role. However, the composition of the gas is expected to change due to a wider variation of sources. In order to mitigate potential challenges for distributors and end-users, a new low-cost gas composition sensor was developed that will be able to monitor the composition and energy content of these gas sources, ranging from biogas to liquid natural gas (LNG). Together with industrial and academic partners a gas sensor was realized that can be inserted in an existing gas grid. A first demonstrator was realized that was small enough to be used in low and medium pressure gas pipes (100 mbarg—8 barg). Adding the pressure and temperature data to the chip readings enables to determine the concentrations of methane, ethane, propane, butane, nitrogen and carbon dioxide, including small fluctuations in water vapor pressure and subsequently calculate the Calorific Value, Wobbe Index and Methane Number. Full article
Open AccessProceedings Novel MEMS Sensor for Detecting Magnetic Particles in Liquids
Proceedings 2018, 2(13), 868; https://doi.org/10.3390/proceedings2130868
Published: 23 November 2018
Viewed by 140 | PDF Full-text (638 KB)
Abstract
We present a novel MEMS sensor for the detection of magnetic particles in liquids, which consists of a microcantilever excited piezoelectrically in resonance and having an integrated planar coil on its free end. Due to the latter component, magnetic particles are attracted and
[...] Read more.
We present a novel MEMS sensor for the detection of magnetic particles in liquids, which consists of a microcantilever excited piezoelectrically in resonance and having an integrated planar coil on its free end. Due to the latter component, magnetic particles are attracted and accumulate on the sensor surface. The additional mass introduced by the particles changes the resonance frequency of the microcantilever serving as measured quantity. To evaluate our design, we dispersed 250 nm iron-oxide particles in de-ionized water and monitored the resonance frequency during particle accumulation. 100 min after measurement start, a total resonance frequency shift of 6 kHz was found, which can easily be measured and shows the high potential of the proposed sensor design. Full article
Open AccessProceedings A Novel Transparent pH Sensor Based on a Nanostructured ITO Electrode Coated with [3,3′-Co(1,2-C2B9H11)2]-Doped Poly(pyrrole)
Proceedings 2018, 2(13), 869; https://doi.org/10.3390/proceedings2130869
Published: 23 November 2018
Viewed by 128 | PDF Full-text (432 KB)
Abstract
A novel transparent and nanostructured ion-sensitive electrode based on indium tin oxide (ITO) coated with cobaltbis(dicarbollide)-doped poly(pyrrole) (PPy) is presented in this work. This metallacarborane-doped PPy was used as conducting polymer due to its high stability and chemical resistance. The ion-sensitive electrode was
[...] Read more.
A novel transparent and nanostructured ion-sensitive electrode based on indium tin oxide (ITO) coated with cobaltbis(dicarbollide)-doped poly(pyrrole) (PPy) is presented in this work. This metallacarborane-doped PPy was used as conducting polymer due to its high stability and chemical resistance. The ion-sensitive electrode was coupled to a miniaturized and low-cost potentiostat, in a final autonomous kit for potentiometric determination of pH. Qualitative calibration of the system revealed Nernstian behavior, resulting promising for novel point-of-care biomedical applications. Full article
Open AccessProceedings Integration of Paper Based Electro-Osmotic Pumps to Continuous Microfluidic Channels
Proceedings 2018, 2(13), 870; https://doi.org/10.3390/proceedings2130870
Published: 26 November 2018
Viewed by 104 | PDF Full-text (905 KB)
Abstract
This work reports for the first-time integration of continuous microfluidic channels to the paper-based electro-osmotic pumps (EOPs) with liquid bridges. In addition, 0.2 μm pore sized cellulose acetate (CA) membrane filter is used to eliminate pressure-driven flow instead of filter paper which is
[...] Read more.
This work reports for the first-time integration of continuous microfluidic channels to the paper-based electro-osmotic pumps (EOPs) with liquid bridges. In addition, 0.2 μm pore sized cellulose acetate (CA) membrane filter is used to eliminate pressure-driven flow instead of filter paper which is common in paper microfluidics and has an average pore size of 10 μm. A factor of 57 increase in hydraulic resistance is achieved with the new paper. Fabrication of the pumps and microfluidic channels using paper, wax, adhesive film and PMMA plates is explained. Volumetric flow rate of 19 nL/min is achieved in the microfluidic system with 61 V/cm electrical field magnitude applied to DI water. The capability of the integrated system is shown with precise liquid motion in a Y-shaped microfluidic channel integrated with two EOPs. Full article
Open AccessProceedings Design of Surface Acoustic Wave Sensors Functionalized with Bisphenol S Based Molecules for Lead Ions Detection
Proceedings 2018, 2(13), 872; https://doi.org/10.3390/proceedings2130872
Published: 26 November 2018
Viewed by 108 | PDF Full-text (383 KB)
Abstract
This study concerns the design of surface acoustic wave sensors functionalized with bisphenol S based molecules for lead ions detection. (4-hydroxyphenyl, 4′-benzyloxyphenyl) sulfone (M1), (4-hydroxyphenyl,4′-anthrylmethyloxyphenyl) sulfone (M2) and (4,4′-bis (anthrylmethyloxyphenyl)) sulfone (M3) were synthesized and then drop-coated on the SAWs sensing areas. Gravimetric
[...] Read more.
This study concerns the design of surface acoustic wave sensors functionalized with bisphenol S based molecules for lead ions detection. (4-hydroxyphenyl, 4′-benzyloxyphenyl) sulfone (M1), (4-hydroxyphenyl,4′-anthrylmethyloxyphenyl) sulfone (M2) and (4,4′-bis (anthrylmethyloxyphenyl)) sulfone (M3) were synthesized and then drop-coated on the SAWs sensing areas. Gravimetric results indicate that the limit of detection of the three sensors is in the picomolar range and that the M3/SAW sensor has the highest affinity towards lead ions compared to M1/SAW and M2/SAW. Density functional theory (DFT) calculations were investigated to support experimental results and to understand the nature of interactions involved between lead ions and the three synthetized molecules. Full article
Open AccessProceedings Versatile and Automated 3D Polydimethylsiloxane (PDMS) Patterning for Large-Scale Fabrication of Organ-on-Chip (OOC) Components
Proceedings 2018, 2(13), 873; https://doi.org/10.3390/proceedings2130873
Published: 5 December 2018
Viewed by 90 | PDF Full-text (597 KB)
Abstract
We present a reproducible process to directly pattern 3-Dimensional (3D) polydimethylsiloxane (PDMS) structures for Organ-on-Chips (OOC) via automated molding. The presented process employs a commercially available system from IC packaging improving the fabrication process for microfluidic channels and thin membranes, which are components
[...] Read more.
We present a reproducible process to directly pattern 3-Dimensional (3D) polydimethylsiloxane (PDMS) structures for Organ-on-Chips (OOC) via automated molding. The presented process employs a commercially available system from IC packaging improving the fabrication process for microfluidic channels and thin membranes, which are components frequently used in OOCs. The process removes the manual steps used previously in the fabrication of microfluidic channels and improves the control over the thickness of the PDMS layers. The process was also employed to fabricate and pattern thin PDMS membranes on silicon wafers, without the use of lithography and etching steps and in combination with 3D structures. The use of foil assisted molding techniques presented in this work is an important step toward the large-scale manufacturing of OOCs. Full article
Open AccessProceedings Gas Sensing Properties of Carbon Nanotubes Decorated with Iridium Oxide Nanoparticles
Proceedings 2018, 2(13), 874; https://doi.org/10.3390/proceedings2130874
Published: 30 November 2018
Viewed by 85 | PDF Full-text (432 KB)
Abstract
The properties of Iridium oxide (IrO2) decorated Multi-Wall Carbon Nanotubes (IrO2-MWCNTs) are studied for detecting nitrogen dioxide and ammonia vapors. IrO2 nanoparticles were synthetized using a hydrolysis and acid condensation growth mechanism, and subsequently employed for decorating the
[...] Read more.
The properties of Iridium oxide (IrO2) decorated Multi-Wall Carbon Nanotubes (IrO2-MWCNTs) are studied for detecting nitrogen dioxide and ammonia vapors. IrO2 nanoparticles were synthetized using a hydrolysis and acid condensation growth mechanism, and subsequently employed for decorating the sidewalls of carbon nanotubes. Decorated MWCNTs films were deposited onto SiO2/Si substrates for achieving chemoresistive gas sensors. NO2 and NH3 gases were detected under different experimental conditions. Higher and more stable responses towards NH3 and NO2 were observed for iridium-oxide nanoparticle decorated MWCNT material, compared to bare MWCNT material. Raman Spectroscopy was employed to study the nanomaterials and the optimal operating temperatures were determined. Full article
Open AccessProceedings A Double-Ended Tuning Fork Based Resonant Pressure Micro-Sensor Relying on Electrostatic Excitation and Piezoresistive Detection
Proceedings 2018, 2(13), 875; https://doi.org/10.3390/proceedings2130875
Published: 27 November 2018
Viewed by 96 | PDF Full-text (571 KB)
Abstract
This study proposes a microfabricated resonant pressure sensor based on electrostatic excitation and low-impedance piezoresistive detection in which a pair of double-ended tuning forks were utilized as resonators for differential outputs. In operations, targeted pressures deforms the pressure-sensitive membrane, resulting in stress variations
[...] Read more.
This study proposes a microfabricated resonant pressure sensor based on electrostatic excitation and low-impedance piezoresistive detection in which a pair of double-ended tuning forks were utilized as resonators for differential outputs. In operations, targeted pressures deforms the pressure-sensitive membrane, resulting in stress variations of two resonators, leading to shifts of the intrinsic resonant frequencies, which were then measured piezoresistively. The developed microfabricated resonant pressure sensor was fabricated using simple SOI-MEMS processes and quantified in both open-loop and closed-loop manners, where the quality factor, differential sensitivity and linear correlation coefficient were quantified as higher than 10,000, 79.4 Hz/kPa and 0.99999, respectively. Compared to previous resonant piezoresistive sensors, the developed device leveraged single-crystal silicon as the piezoresistor, with advantages in simple sensing structures and fabrication steps. Furthermore, the differential setup was adopted in this study which can further improve the performances of the developed sensors. Full article
Open AccessProceedings Tomographic Measurement of Ammonia Distribution on a Hot Gas Test Bench
Proceedings 2018, 2(13), 876; https://doi.org/10.3390/proceedings2130876
Published: 30 November 2018
Viewed by 98 | PDF Full-text (504 KB)
Abstract
In situ optical measurement systems for gas detection with high temporal resolution enable new possibilities of detection opportunities for continuous pipe gas streams. A tomographic absorption-based measurement system has been developed to detect the ammonia (NH3) concentration distribution within an exhaust
[...] Read more.
In situ optical measurement systems for gas detection with high temporal resolution enable new possibilities of detection opportunities for continuous pipe gas streams. A tomographic absorption-based measurement system has been developed to detect the ammonia (NH3) concentration distribution within an exhaust pipe on a hot gas test bench. Multiple ammonia line concentrations are measured in situ by applying nondispersive absorption spectroscopy in the deep ultraviolet (DUV) region. The detectors consist of photodiodes in combination with optimized transimpedance amplifiers (TIV) allowing high sampling rates up to 3 kHz while providing a high signal-to-noise ratio (SNR). Despite the short path length of only eight centimeters a detection limit of 1 ppm has been achieved. Full article
Open AccessProceedings Continuous Live-Cell Culture Monitoring by Compact Lensless LED Microscopes
Proceedings 2018, 2(13), 877; https://doi.org/10.3390/proceedings2130877
Published: 5 December 2018
Viewed by 103 | PDF Full-text (1023 KB)
Abstract
A compact lensless microscope comprising a custom-made LED engine and a CMOS imaging sensor has been developed for live-cell culture imaging inside a cell incubator environment. The imaging technique is based on digital inline-holographic microscopy, while the image reconstruction is carried out by
[...] Read more.
A compact lensless microscope comprising a custom-made LED engine and a CMOS imaging sensor has been developed for live-cell culture imaging inside a cell incubator environment. The imaging technique is based on digital inline-holographic microscopy, while the image reconstruction is carried out by angular spectrum approach with a custom written software. The system was tested with various biological samples including immortalized mouse astrocyte cells inside a petri dish. Besides the imaging possibility, the capability of automated cell counting and tracking could be demonstrated. By using image sensors capable of video frame rate, time series of cell movement can be captured. Full article
Open AccessProceedings A CMOS-Based Thermopile Array Fabricated on a Single SiO2 Membrane
Proceedings 2018, 2(13), 878; https://doi.org/10.3390/proceedings2130878
Published: 22 November 2018
Viewed by 116 | PDF Full-text (1560 KB)
Abstract
We present a novel thermopile-based infrared (IR) sensor array fabricated on a single CMOS dielectric membrane, comprising of poly-silicon p+ and n+ elements. Processing of the chip is simplified by fabricating the entire array on a single membrane and by using
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We present a novel thermopile-based infrared (IR) sensor array fabricated on a single CMOS dielectric membrane, comprising of poly-silicon p+ and n+ elements. Processing of the chip is simplified by fabricating the entire array on a single membrane and by using standard CMOS Al metal layers for thermopile cold junction heatsinking. On a chip area of 1.76 mm × 1.76 mm, with a membrane size of 1.2 mm × 1.2 mm, we fabricated IR sensor arrays with 8 × 8 to 100 × 100 pixels. The 8 × 8 pixel device has <2% thermal crosstalk, a responsivity of 36 V/W and enhanced optical absorption in the 8–14 µm waveband, making it particularly suitable for people presence sensing. Full article
Open AccessProceedings Design of Miniaturized, Self-Out-Readable Cantilever Resonator for Highly Sensitive Airborne Nanoparticle Detection
Proceedings 2018, 2(13), 879; https://doi.org/10.3390/proceedings2130879
Published: 3 December 2018
Viewed by 64 | PDF Full-text (747 KB)
Abstract
In this paper, a self-out-readable, miniaturized cantilever resonator for highly sensitive
airborne nanoparticle (NP) detection is presented. The cantilever, which is operated in the
fundamental in-plane resonance mode, is used as a microbalance with femtogram resolution. To
achieve a maximum measurement signal of
[...] Read more.
In this paper, a self-out-readable, miniaturized cantilever resonator for highly sensitive
airborne nanoparticle (NP) detection is presented. The cantilever, which is operated in the
fundamental in-plane resonance mode, is used as a microbalance with femtogram resolution. To
achieve a maximum measurement signal of the piezo resistive Wheatstone half-bridge, the
geometric parameters of the sensor design were optimized by finite element modelling (FEM).
Struts at the sides of the cantilever resonator act as piezo resistors and enable an electrical read-out
of the phase information of the cantilever movement whereby they do not contribute to the
resonators rest mass. For the optimized design, a resonator mass of 0.93 ng, a resonance frequency
of ~440 kHz, and thus a theoretical sensitivity of 4.23 fg/Hz can be achieved. A μ-channel guiding a
particle-laden air flow towards the cantilever is integrated into the sensor chip. Electrically charged
NPs will be collected by an electrostatic field between the cantilever and a counter-electrode at the
edges of the μ-channel. Such μ-channels will also be used to accomplish particle separation for sizeselective
NP detection. Throughout, the presented airborne NP sensor is expected to demonstrate
significant improvements in the field of handheld, MEMS-based NP monitoring devices. Full article
Open AccessProceedings Pixel-Wise Multispectral Sensing System Using Nanostructured Filter Matrix for Biomedical Applications
Proceedings 2018, 2(13), 880; https://doi.org/10.3390/proceedings2130880
Published: 29 November 2018
Viewed by 98 | PDF Full-text (1179 KB)
Abstract
In this work, a novel multispectral sensing system consisting of nanostructured filter matrix and a charge-coupled device (CCD)-based image sensor has been developed to overcome the limitation of the conventional pigment filtered sensors, which are difficult to be fabricated at a microscale and
[...] Read more.
In this work, a novel multispectral sensing system consisting of nanostructured filter matrix and a charge-coupled device (CCD)-based image sensor has been developed to overcome the limitation of the conventional pigment filtered sensors, which are difficult to be fabricated at a microscale and usually showing a pronounced degradation. By designing the filters in guided-mode resonance (GMR) architecture, light transmission efficiencies of ~90% with low sidebands and sharp peaks can be obtained, which are critical characteristics for realizing precise optical measurement systems. To optimize the transmission functions, various materials and structural parameters have been simulated. Electron beam nanolithography is employed in the device fabrication to fabricate pixel-wise independent filter functions. After being characterized in terms of their wavelength filtering capability, the developed GMR filters are then combined with image sensors, particularly for addressing biological applications. Full article
Open AccessProceedings Development of a Device for Staged Determination of Water Activity and Moisture Content
Proceedings 2018, 2(13), 881; https://doi.org/10.3390/proceedings2130881
Published: 10 December 2018
PDF Full-text (356 KB)
Abstract
Moisture content and water activity are important parameters for quality characterization
of products like bulk materials, powders, granules. Thus, an exact determination is necessarily
required in a wide range of industrial applications. Moisture of materials is the content of
non-chemically bound water in
[...] Read more.
Moisture content and water activity are important parameters for quality characterization
of products like bulk materials, powders, granules. Thus, an exact determination is necessarily
required in a wide range of industrial applications. Moisture of materials is the content of
non-chemically bound water in a solid or liquid. Water activity (aw) is a characteristic/parameter of
the non-chemically bound (“free”) water in materials and is measured as humidity over a
solid/liquid surface at constant temperature (equilibrium moisture content). It is an important
parameter to characterize the quality of e.g., pharmaceutical and food products. In our
contribution, we present the developed MOISHUM device for staged determination of water
activity and moisture content of liquid and solid materials. Full article
Open AccessProceedings Sensors for Thermal Characterization of Solid and Liquid Samples by 3-Omega Method
Proceedings 2018, 2(13), 883; https://doi.org/10.3390/proceedings2130883
Published: 28 November 2018
Viewed by 100 | PDF Full-text (780 KB)
Abstract
Microchips have been designed and fabricated for the fast thermal characterization of samples by extension of the 3-omega method. Both solid and liquid samples can be measured by applying a small amount of material under investigation on the chip containing a micro heater/sensor.
[...] Read more.
Microchips have been designed and fabricated for the fast thermal characterization of samples by extension of the 3-omega method. Both solid and liquid samples can be measured by applying a small amount of material under investigation on the chip containing a micro heater/sensor. Two types of chips have been fabricated and tested: silicon chips with porous silicon (PS) layer as thermal isolator and glass chips with through glass vias (TGVs) for the back side contacting of the top side heater/sensor. Full article
Open AccessProceedings Energy Harvesting Powered Wireless Vibration Analyser
Proceedings 2018, 2(13), 884; https://doi.org/10.3390/proceedings2130884
Published: 29 November 2018
Viewed by 77 | PDF Full-text (567 KB)
Abstract
In this work we present a complex, wireless, ambient energy powered and easy-to-use solution for vibration analysis. It is designed to incorporate the latest commercial technologies and achievements in the field of energy harvesting and wireless sensor networks with an emphasis on energy
[...] Read more.
In this work we present a complex, wireless, ambient energy powered and easy-to-use solution for vibration analysis. It is designed to incorporate the latest commercial technologies and achievements in the field of energy harvesting and wireless sensor networks with an emphasis on energy efficient spectrum estimation algorithms for embedded systems. This solution is realized on a small printed circuit board and contains all the necessary circuit components for hybrid energy harvesting; acceleration sensing; data acquisition, storing and analysis; and wireless communication. The on-board microcontroller was programmed to choose the most energy-efficient data handling algorithm (direct transfer or embedded analysis) based on the weighed combination of user settings and ambient energy. We tested and calibrated our system in laboratory environment with reference sensors, as well as in an engine room, simulating practical applications. Full article
Open AccessProceedings Polydimethylsiloxane (PDMS) Waveguide Sensor Detecting Fluid Flow Velocity by Mimicking the Fish Lateral Line Organ
Proceedings 2018, 2(13), 885; https://doi.org/10.3390/proceedings2130885
Published: 23 November 2018
Viewed by 96 | PDF Full-text (361 KB)
Abstract
Accurate measurement of fluid flow velocities is challenging but essential in many disciplines. Inspiration of possible measurement methods can come from nature, for example from the lateral line organ of fish, which is comprised of hair cells embedded in a gelatinous cupula. When
[...] Read more.
Accurate measurement of fluid flow velocities is challenging but essential in many disciplines. Inspiration of possible measurement methods can come from nature, for example from the lateral line organ of fish, which is comprised of hair cells embedded in a gelatinous cupula. When the cupula is deflected by water movement, the hair cells initiate neural signals that generate an accurate image of the fish’s surroundings. We built a flow sensor mimicking a hair cell, yet coupled it with an optical detection method. Fluid flow bends the waveguide; this leads to a measurable light loss that depends linearly on the waveguide deflection. Full article
Open AccessProceedings Silk Fibroin Pads for Whole Blood Glucose Determination
Proceedings 2018, 2(13), 886; https://doi.org/10.3390/proceedings2130886
Published: 30 November 2018
Viewed by 85 | PDF Full-text (528 KB)
Abstract
In this work, we present a durable and miniaturized photonic lab on a chip (PhLOC) integrating functionalized silk fibroin pads for optical glucose quantification in whole blood samples. The PhLOC consists of a poly(methyl methacrylate) (PMMA) disposable structure for the pad holding and
[...] Read more.
In this work, we present a durable and miniaturized photonic lab on a chip (PhLOC) integrating functionalized silk fibroin pads for optical glucose quantification in whole blood samples. The PhLOC consists of a poly(methyl methacrylate) (PMMA) disposable structure for the pad holding and a coupling system for commercial optic fibers connection. The silk matrix, together with the PMMA design, has the capability to separate the plasma from the cell fraction of whole blood by plasma diffusion into the silk, minimizing the absorbance interferences from the hemoglobin of the erythrocytes. Then, the enzymes present in the matrix react with the glucose in the sample and produce a color change in an amplified process where the analyte—mediator—matrix interacts sequentially, increasing the common signal from the oxidized mediator (2 fold). The sensor works in the adequate linear range to distinguish between healthy and unhealthy glucose levels (0 to 12 mM), with a sensitivity of 0.084 a.u. mM1, a limit of detection of 0.18 mM and a limit of quantification of 1.44 mM. Furthermore, durability of the sensor is remarkable, maintaining its response unchangeable during the first 7 months of tests. Full article
Open AccessProceedings Area-Selective Growth of Aligned ZnO Nanorod Arrays for MEMS Device Applications
Proceedings 2018, 2(13), 887; https://doi.org/10.3390/proceedings2130887
Published: 23 November 2018
Viewed by 106 | PDF Full-text (1184 KB)
Abstract
ZnO nanorods (NRs) arrays with good vertical alignment were selectively grown on microscale patterned surfaces by a MEMS-compatible, low-temperature chemical-bath deposition method (CBD). The direct-current (DC) sputtered and subsequently annealed ZnO seed-layer was found to have a crucial effect on the ZnO NRs
[...] Read more.
ZnO nanorods (NRs) arrays with good vertical alignment were selectively grown on microscale patterned surfaces by a MEMS-compatible, low-temperature chemical-bath deposition method (CBD). The direct-current (DC) sputtered and subsequently annealed ZnO seed-layer was found to have a crucial effect on the ZnO NRs growth. Depending on the pre-annealing temperature between 200 °C and 700 °C, which is compatible with our microcantilever fabrication process, diameters and area densities of the NRs of 60–99 nm and 17–27 µm−2 were observed, respectively, with the best alignment at 600 °C. A surface-area enlargement factor of 48 was achieved with respect to a ZnO layer indicating the potential of ZnO NRs arrays for MEMS applications, such as gas sensing. Full article
Open AccessProceedings Optimizing a Cantilever Measurement System towards High Speed, Nonreactive Contact-Resonance-Profilometry
Proceedings 2018, 2(13), 889; https://doi.org/10.3390/proceedings2130889
Published: 21 November 2018
Viewed by 100 | PDF Full-text (1579 KB)
Abstract
An existing phase-locked-loop (PLL) based contact-resonance measurement system is studied and optimized. Improvements to the electronics’ circuit to reduce both nonlinear behavior and noise are realized and experimentally tested. The improvements enable to analyze signals even at highly damped vibrations of the cantilever.
[...] Read more.
An existing phase-locked-loop (PLL) based contact-resonance measurement system is studied and optimized. Improvements to the electronics’ circuit to reduce both nonlinear behavior and noise are realized and experimentally tested. The improvements enable to analyze signals even at highly damped vibrations of the cantilever. Full article
Open AccessProceedings Gas Detection Using LMR-Based Optical Fiber Sensors
Proceedings 2018, 2(13), 890; https://doi.org/10.3390/proceedings2130890
Published: 21 November 2018
Viewed by 141 | PDF Full-text (903 KB)
Abstract
This work presents a first approach to the utilization of Lossy Mode Resonance (LMR) based optical fiber sensors for gas detection. The optical sensor is based on a SnO2 thin-film fabricated onto the core of cladding removed multimode fibers (MMF). The time
[...] Read more.
This work presents a first approach to the utilization of Lossy Mode Resonance (LMR) based optical fiber sensors for gas detection. The optical sensor is based on a SnO2 thin-film fabricated onto the core of cladding removed multimode fibers (MMF). The time response of the device to four different gases (NH3, NO, CO2 and O2) was monitored obtaining the best sensitivity for NO whereas the response to NH3 revealed the best repeatability. Full article
Open AccessProceedings Transferable Substrateless GaN LED Chips Produced by Femtosecond Laser Lift-Off for Flexible Sensor Applications
Proceedings 2018, 2(13), 891; https://doi.org/10.3390/proceedings2130891
Published: 21 November 2018
Viewed by 148 | PDF Full-text (603 KB)
Abstract
Transferable substrate-less InGaN/GaN light-emitting diode (LED) chips have successfully been fabricated in a laser lift-off (LLO) process employing high power ultrashort laser pulses with a wavelength of 520 nm. The irradiation of the sample was conducted in two sequential steps involving high and
[...] Read more.
Transferable substrate-less InGaN/GaN light-emitting diode (LED) chips have successfully been fabricated in a laser lift-off (LLO) process employing high power ultrashort laser pulses with a wavelength of 520 nm. The irradiation of the sample was conducted in two sequential steps involving high and low pulse energies from the backside of the sapphire substrate, which led to self-detachment of the GaN stack layer without any additional tape release procedure. To guarantee their optoelectrical function and surface quality, the lifted LED chips were assessed in scanning electron microscopy (SEM) and electroluminescence (EL) measurements. Moreover, surface characterizations were done using atomic force microscopy (AFM) and Auger Electron Spectroscopy (AES). Full article
Open AccessProceedings InGaN/GaN nanoLED Arrays as a Novel Illumination Source for Biomedical Imaging and Sensing Applications
Proceedings 2018, 2(13), 892; https://doi.org/10.3390/proceedings2130892
Published: 6 December 2018
Viewed by 90 | PDF Full-text (984 KB)
Abstract
Guidelines for the fabrication of nanoscale light-emitting diode arrays (i.e., nanoLED arrays) based on patterned gallium nitride (GaN) with very small dimensions and pitches have been derived in this work. Several challenges during top-down LED array processing have been tackled involving hybrid etching
[...] Read more.
Guidelines for the fabrication of nanoscale light-emitting diode arrays (i.e., nanoLED arrays) based on patterned gallium nitride (GaN) with very small dimensions and pitches have been derived in this work. Several challenges during top-down LED array processing have been tackled involving hybrid etching and polymer-based planarization to yield completely insulated highaspect-ratio LED fin structures and support the creation of p-GaN crossing line contacts, respectively. Furthermore, simulations of the light emission patterns were also performed providing hints for enhancing the device designs. As a result, regardless of the required device processing optimization, the developed nanoLED arrays are expected to offer high potential as novel illumination sources in biomedical imaging and sensing applications (e.g., mini compact microscopes and wearable biological/chemical nanoparticle counters) Full article
Open AccessProceedings Development of Copper Oxide Thin Film for Lossy Mode Resonance-Based Optical Fiber Sensor
Proceedings 2018, 2(13), 893; https://doi.org/10.3390/proceedings2130893
Published: 28 November 2018
Viewed by 113 | PDF Full-text (760 KB)
Abstract
In this work we present the study of copper(II) oxide thin films for the fabrication of lossy mode resonance-based (LMR) optical fiber sensors. This material has proven to be capable of generating such resonances with a promising result. Their optimal optical properties have
[...] Read more.
In this work we present the study of copper(II) oxide thin films for the fabrication of lossy mode resonance-based (LMR) optical fiber sensors. This material has proven to be capable of generating such resonances with a promising result. Their optimal optical properties have allowed the achievement of a sensitivity of 7234 nm/RIU, higher than that obtained with other metal oxides such a SnO2, indium tin oxide (ITO), aluminum doped zinc oxide (AZO) or indium-gallium-zinc oxide (IGZO). The use of this new film may facilitate the use of LMR based sensors for applications that require maximum sensitivity and stability. Full article
Open AccessProceedings Silicon Based Nano-Thermoelectric Bolometers for Infrared Detection
Proceedings 2018, 2(13), 894; https://doi.org/10.3390/proceedings2130894
Published: 6 December 2018
Viewed by 90 | PDF Full-text (1312 KB)
Abstract
The state-of-the-art infrared (IR) detection uses quantum photodetectors and bolometers. Quantum IR photodetectors are expensive and require cooling, and exotic and toxic materials. Whereas, bolometers are cost-efficient and uncooled, but they are much slower and less sensitive. Recently we have demonstrated that ultra-thin,
[...] Read more.
The state-of-the-art infrared (IR) detection uses quantum photodetectors and bolometers. Quantum IR photodetectors are expensive and require cooling, and exotic and toxic materials. Whereas, bolometers are cost-efficient and uncooled, but they are much slower and less sensitive. Recently we have demonstrated that ultra-thin, highly-doped silicon membranes can be used to build fast and highly-sensitive thermoelectric bolometers. We present the fabrication of these devices, electro-thermal characterization results, and estimate the full potential of this technology. Full article
Open AccessProceedings Synthesis of Fluorescein Aldehydes for the Sensitive Detection of L-Cysteine
Proceedings 2018, 2(13), 895; https://doi.org/10.3390/proceedings2130895
Published: 27 November 2018
Viewed by 115 | PDF Full-text (518 KB)
Abstract
Amino acids containing thiol-groups such as Cysteine (Cys), Homocysteine (Hcy), and Glutathione play an important role in a great variety of biological processes. However, too low, but also too high concentrations can have negative effects on human health. Therefore, it is of great
[...] Read more.
Amino acids containing thiol-groups such as Cysteine (Cys), Homocysteine (Hcy), and Glutathione play an important role in a great variety of biological processes. However, too low, but also too high concentrations can have negative effects on human health. Therefore, it is of great importance to sensitively detect these risk factors for cardiovascular and neuronal diseases. Furthermore, Cys is an essential amino acid for the growth of pathogenic water-borne bacteria, like Legionella sp. Hence, a reliable, sensitive and selective Cys-detection method that is incorporated into automated biosensors would represent a great tool for a broad range of biological and medical applications. We describe the simple synthesis of fluorescein aldehyde probes for the detection of biologically important thiols, focusing on Cys. The probes displayed highly sensitive responses to L-Cysteine hydrochloride monohydrate in the range of their physiologically relevant levels in the visible and UV spectral region. Full article
Open AccessProceedings Modelling Fluid Damping of Non-Conventional Vibration Modes in MEMS Resonators
Proceedings 2018, 2(13), 896; https://doi.org/10.3390/proceedings2130896
Published: 27 November 2018
Viewed by 108 | PDF Full-text (768 KB)
Abstract
Resonant micro- and nanoelectromechanical systems (MEMS/NEMS) are typically subject to interaction with a liquid or gaseous environment. Recently, it has been demonstrated that non-conventional eigenmodes exhibit remarkably high quality factors (Q factors) in liquids. However, the physical origin of this phenomenon remains elusive.
[...] Read more.
Resonant micro- and nanoelectromechanical systems (MEMS/NEMS) are typically subject to interaction with a liquid or gaseous environment. Recently, it has been demonstrated that non-conventional eigenmodes exhibit remarkably high quality factors (Q factors) in liquids. However, the physical origin of this phenomenon remains elusive. Here we introduce a definition of non-conventional eigenmodes for cantilever structures and develop a boundary integral method for describing the interaction of an incompressible viscous fluid and a non-conventional eigenmode of a MEMS/NEMS resonator. With this framework we are able to study the influence of the mode shape on the fluid-structure interaction. Full article
Open AccessProceedings Structural Modifications in Free-Standing InGaN/GaN LEDs after Femtosecond Laser Lift-Off
Proceedings 2018, 2(13), 897; https://doi.org/10.3390/proceedings2130897
Published: 29 November 2018
Viewed by 90 | PDF Full-text (1085 KB)
Abstract
A laser lift-off (LLO) process has been developed for detaching thin InGaN/GaN lightemitting diodes (LED) from their original sapphire substrates by applying an ultrafast laser. LLO is usually based on intense UV irradiation, which is transmitted through the sapphire substrate and subsequently absorbed
[...] Read more.
A laser lift-off (LLO) process has been developed for detaching thin InGaN/GaN lightemitting diodes (LED) from their original sapphire substrates by applying an ultrafast laser. LLO is usually based on intense UV irradiation, which is transmitted through the sapphire substrate and subsequently absorbed at the interface to the epitaxially grown GaN stack. Here, we present a successful implementation of a two-step LLO process with 350 fs short pulses in the green spectral range (520 nm) based on a two-photon absorption mechanism. Cathodo- and electroluminescence experiments have proven the functionality of the LLO-based chips. The impact of radiation on the material quality was analysed with scanning (SEM) and transmission electron microscopy (TEM), revealing structural modifications inside the GaN layer in some cases. Full article
Open AccessProceedings Wireless Sensors Network Monitoring of Saharan Dust Events in Bari, Italy
Proceedings 2018, 2(13), 898; https://doi.org/10.3390/proceedings2130898
Published: 5 December 2018
Viewed by 101 | PDF Full-text (972 KB)
Abstract
A sensors network based on 8 stationary nodes distributed in Bari (Southern Italy) has
been deployed for urban air quality monitoring during advection events of Saharan dust in the
period 2015–2017. The low-cost sensor-systems have been installed in specific sites (buildings,
offices, schools,
[...] Read more.
A sensors network based on 8 stationary nodes distributed in Bari (Southern Italy) has
been deployed for urban air quality monitoring during advection events of Saharan dust in the
period 2015–2017. The low-cost sensor-systems have been installed in specific sites (buildings,
offices, schools, streets, airport) to assess the PM10 concentration at high spatial and temporal
resolution in order to supplement the expensive official air monitoring stations for citizen science
purposes. Continuous measurements were performed by a cost-effective optical particle counter
(PM10), including temperature and relative humidity sensors. They are operated to assess the
performance during a long-term campaign (July 2015–December 2017) of 30 months for smart cities
applications. The sensor data quality has been evaluated by comparison to the reference data of the
9 Air Quality Monitoring Stations (AQMS), managed by local environmental agency (ARPA-Puglia)
in the Bari city. Full article
Open AccessProceedings Impedimetric Characterization of Interdigitated Electrode Arrays for Biosensor Applications
Proceedings 2018, 2(13), 899; https://doi.org/10.3390/proceedings2130899
Published: 30 November 2018
Viewed by 84 | PDF Full-text (684 KB)
Abstract
We present recent results of the electrochemical impedance spectroscopy (EIS) measurements for interdigitated electrode arrays (IDAs) ranging from several micrometers down to hundreds of nanometers. Simulations have shown that the electric field strength between the electrodes scales with the gap size. Therefore, electrodes
[...] Read more.
We present recent results of the electrochemical impedance spectroscopy (EIS) measurements for interdigitated electrode arrays (IDAs) ranging from several micrometers down to hundreds of nanometers. Simulations have shown that the electric field strength between the electrodes scales with the gap size. Therefore, electrodes of varying gap sizes were fabricated and functionalized with ssDNA to empirically validate these findings. The results have shown that the impedimetric response strongly correlates with the width of the electrode fingers: the smaller the electrode gap, the larger the impedance increase. Full article
Open AccessProceedings Highly Sensitive Surface Acoustic Wave Magnetic Field Sensor Using Multilayered TbCo2/FeCo Thin Film
Proceedings 2018, 2(13), 902; https://doi.org/10.3390/proceedings2130902
Published: 30 November 2018
Viewed by 98 | PDF Full-text (670 KB)
Abstract
Over the last decades, the use of Surface Acoustic Waves (SAW) has emerged as a promising technology in many applications such as filters, signal processing but also sensors. We report the fabrication and the characterization of a SAW delay line magnetic field sensor
[...] Read more.
Over the last decades, the use of Surface Acoustic Waves (SAW) has emerged as a promising technology in many applications such as filters, signal processing but also sensors. We report the fabrication and the characterization of a SAW delay line magnetic field sensor using uniaxial multi-layered 14×[TbCo2(3.7nm)/FeCo(4nm)] nanostructured thin film deposited on Y36° Lithium Niobate (Figure 1a). The sensor shows an interesting dependency to a tunable bias magnetic field with different orientations relative to the easy axis. The obtained results are well explained using an equivalent piezo-magnetic model described in a previous work. Full article
Open AccessProceedings Investigation of Electrochemical Processes in CO2 Sensitive Electrodes
Proceedings 2018, 2(13), 903; https://doi.org/10.3390/proceedings2130903
Published: 11 December 2018
PDF Full-text (686 KB)
Abstract
The electrode processes governing response behavior of a solid electrolyte CO2 sensor have been studied using electrochemical impedance spectroscopy on symmetric cells exposed to various temperatures and gas compositions. It was shown that the electrochemical processes leading to potential formation at the
[...] Read more.
The electrode processes governing response behavior of a solid electrolyte CO2 sensor have been studied using electrochemical impedance spectroscopy on symmetric cells exposed to various temperatures and gas compositions. It was shown that the electrochemical processes leading to potential formation at the Au/Na2CO3 electrode can be described by adapting models commonly used in the field of molten carbonate fuel cells. Full article
Open AccessProceedings Optimized Batch Process for Organic MEMS Devices
Proceedings 2018, 2(13), 904; https://doi.org/10.3390/proceedings2130904
Published: 28 November 2018
Viewed by 110 | PDF Full-text (477 KB)
Abstract
Recently, organic electromechanical transducers have attracted intense scientific and technological interest due to their unique mechanical flexibility and their piezoelectric properties. However, the fabrication of organic MEMS devices is challenging. For example, a lift-off process cannot be used on polymers, because of the
[...] Read more.
Recently, organic electromechanical transducers have attracted intense scientific and technological interest due to their unique mechanical flexibility and their piezoelectric properties. However, the fabrication of organic MEMS devices is challenging. For example, a lift-off process cannot be used on polymers, because of the solvent in photoresists. Here, we present a straightforward and low-cost batch process for organic MEMS devices using standard micromachining techniques. As organic material we used the ferroelectric (co-)polymer poly(vinylidene fluoride-trifluorethylene) (P(VDF-TrFE)). The integration of the polymer in a CMOS-compatible process was optimized in terms of deposition and patterning of the polymer and the corresponding metal layers. Micromachined devices, such as capacitors and cantilevers, were fabricated and analysed. The ferroelectric perfomance was evaluated by electrical and electromechanical measurements. Our first results indicate that the proposed fabrication process is reliable resulting in well-functioning organic MEMS devices. We measured as piezoelectric constant a d33 of −32 pm/V with our organic P(VDF-TrFE) capacitors. Full article
Open AccessProceedings Machine-Readable Pattern for Colorimetric Sensor Interrogation
Proceedings 2018, 2(13), 906; https://doi.org/10.3390/proceedings2130906
Published: 29 November 2018
Viewed by 105 | PDF Full-text (1025 KB)
Abstract
We present a systematic methodology to generate machine-readable patterns embodying all the elements needed to carry out colorimetric measurements with conventional color cameras in an automated, robust and accurate manner. Our approach relies on the well-stablished machine-readable features of the QR Codes, to
[...] Read more.
We present a systematic methodology to generate machine-readable patterns embodying all the elements needed to carry out colorimetric measurements with conventional color cameras in an automated, robust and accurate manner. Our approach relies on the well-stablished machine-readable features of the QR Codes, to detect the pattern, identify the color reference elements and the colorimetric spots, to calibrate the color of the image and to conclude a quantitative measurement. We illustrate our approach with a NH3 colorimetric indicator operating at distinct color temperature ambient lights, demonstrating that with our design, consistent measurements can be achieved, with independence on the illumination conditions. Full article
Open AccessProceedings Fabrication of SnO2 Flexible Sensor by Inkjet Printing Technology
Proceedings 2018, 2(13), 907; https://doi.org/10.3390/proceedings2130907
Published: 26 November 2018
Viewed by 109 | PDF Full-text (432 KB)
Abstract
In this work, a flexible tin oxide (SnO2) gas sensor was successfully fabricated by inkjet printing technology. This thin film deposition technique requires the formulation of stable suspensions with specific fluidic properties. Aqueous Sol-gel method was applied to synthesize a stable
[...] Read more.
In this work, a flexible tin oxide (SnO2) gas sensor was successfully fabricated by inkjet printing technology. This thin film deposition technique requires the formulation of stable suspensions with specific fluidic properties. Aqueous Sol-gel method was applied to synthesize a stable sol based on tin oxide, then transformed into ink with the appropriate viscosity and surface tension to be printed using a drop-on-demand piezoelectric inkjet printer. Thermal analyses of synthetized sol show that a crystallized structure of SnO2 could be obtained at 350 °C, which is lower than crystallization temperatures of SnO2 previously reported in the literature, and entirely consistent with our plastic substrate. The printed thin-film was then sintered at 350 °C on polyimide foil (Upilex-50S) and characterized as sensor. Full article
Open AccessProceedings Simulation and Characterization of a Nonlinear Dual-Frequency Piezoelectric Energy Harvester
Proceedings 2018, 2(13), 908; https://doi.org/10.3390/proceedings2130908
Published: 23 November 2018
Viewed by 98 | PDF Full-text (843 KB)
Abstract
In this paper, we present a concept, simulation and characterization results of a dual-frequency piezoelectric energy harvester with magnetic frequency tuning capabilities. We demonstrate that the frequency-agile multi-mode capability enables the device to harvest on a wider range of operating frequencies than classical
[...] Read more.
In this paper, we present a concept, simulation and characterization results of a dual-frequency piezoelectric energy harvester with magnetic frequency tuning capabilities. We demonstrate that the frequency-agile multi-mode capability enables the device to harvest on a wider range of operating frequencies than classical vibration harvesters. Full article
Open AccessProceedings Systematic Electro-Optical Study of Photodiodes in Intrinsic Material (Lowly Doped) with Backend Stack Optimization
Proceedings 2018, 2(13), 909; https://doi.org/10.3390/proceedings2130909
Published: 26 November 2018
Viewed by 92 | PDF Full-text (989 KB)
Abstract
This paper constitutes the analysis of the impact of low doped intrinsic p-type EPI thickness (20 µm and 30 µm) and bottom anti-reflective coating on the electrical and optical performance of various PIN photodiodes designs. The intrinsic p-type layer with a target resistivity
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This paper constitutes the analysis of the impact of low doped intrinsic p-type EPI thickness (20 µm and 30 µm) and bottom anti-reflective coating on the electrical and optical performance of various PIN photodiodes designs. The intrinsic p-type layer with a target resistivity of 400 Ω cm is an epitaxial layer (iEPI) grown on a low resistive substrate of 20 mΩ cm. Optimization of the photodiode’s spectral responsivity (for a specific wavelength) includes a Bottom Anti-Reflective Coating (BARC) layer deposited over the silicon surface. BARC thickness is optimized for λ = 425 nm, λ = 750 nm and λ = 900 nm wavelengths. With respective BARC in place, the photodiode’s quantum efficiency (QE) approaches 100% for λ = 750 nm with 20 µm and 30 µm iEPI thickness and for λ = 900 nm with 30 µm iEPI reaching also a maximum spectral response of 0.63 A/W at 800 nm. QE of 72% could be achieved at 425 nm. The leakage current varies from 3.5 pA for 20 µm iEPI thickness to 10 pA for 30 µm at 1 V reverse biasing for 365 µm circular PIN photodiode. Full article
Open AccessProceedings Glyphosate Detection: An Innovative Approach by Using Chemoresistive Gas Sensors
Proceedings 2018, 2(13), 910; https://doi.org/10.3390/proceedings2130910
Published: 27 November 2018
Viewed by 123 | PDF Full-text (526 KB)
Abstract
Glyphosate is the most frequently used herbicide worldwide, its hazard potential is unclear and nowadays a threshold limit value has not yet been determined. We used eight chemoresistive gas sensors based on semiconducting nanopowders for the identification of N-(phosphonomethyl) glycine in air.
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Glyphosate is the most frequently used herbicide worldwide, its hazard potential is unclear and nowadays a threshold limit value has not yet been determined. We used eight chemoresistive gas sensors based on semiconducting nanopowders for the identification of N-(phosphonomethyl) glycine in air. The sensors were tested at their proper working temperature in presence of volatile glyphosate at concentrations within the range of 6 ppb–1 ppm, i.e., a plausible interval of interest for its monitoring. The sensing material that best performed was a solid solution of Tungsten oxide and Tin oxide (WS30). This study opens up to design portable devices suitable for monitoring glyphosate concentrations at which workers and people are exposed. Full article
Open AccessProceedings 3D Gas Distribution with and without Artificial Airflow: An Experimental Study with a Grid of Metal Oxide Semiconductor Gas Sensors
Proceedings 2018, 2(13), 911; https://doi.org/10.3390/proceedings2130911
Published: 29 November 2018
Viewed by 155 | PDF Full-text (998 KB)
Abstract
Gas distribution modelling can provide potentially life-saving information when assessing the hazards of gaseous emissions and for localization of explosives, toxic or flammable chemicals. In this work, we deployed a three-dimensional (3D) grid of metal oxide semiconductor (MOX) gas sensors deployed in an
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Gas distribution modelling can provide potentially life-saving information when assessing the hazards of gaseous emissions and for localization of explosives, toxic or flammable chemicals. In this work, we deployed a three-dimensional (3D) grid of metal oxide semiconductor (MOX) gas sensors deployed in an office room, which allows for novel insights about the complex patterns of indoor gas dispersal. 12 independent experiments were carried out to better understand dispersion patters of a single gas source placed at different locations of the room, including variations in height, release rate and air flow profiles. This dataset is denser and richer than what is currently available, i.e., 2D datasets in wind tunnels. We make it publicly available to enable the community to develop, validate, and compare new approaches related to gas sensing in complex environments. Full article
Open AccessProceedings AlN-on-Si Square Diaphragm Piezoelectric Micromachined Ultrasonic Transducer with Extended Range of Detection
Proceedings 2018, 2(13), 913; https://doi.org/10.3390/proceedings2130913
Published: 27 November 2018
Viewed by 110 | PDF Full-text (923 KB)
Abstract
We present aluminum nitride (AlN) on silicon (Si) CMOS-compatible piezoelectric micromachined ultrasonic transducers (pMUTs) with an extended detection range of up to 140 cm for touchless sensing applications. The reported performance surpasses the current state-of-art for AlN-based pMUTs in terms of the maximum
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We present aluminum nitride (AlN) on silicon (Si) CMOS-compatible piezoelectric micromachined ultrasonic transducers (pMUTs) with an extended detection range of up to 140 cm for touchless sensing applications. The reported performance surpasses the current state-of-art for AlN-based pMUTs in terms of the maximum range of detection using just a pair of pMUTs (as opposed to an array of pMUTs). The extended range of detection has been realized by using a larger diaphragm allowed by fabricating a thicker diaphragm than most other pMUTs reported to date. Using a pair of pMUTs, we experimentally demonstrate the capability of range-finding by correlating the time-of-flight (TOF) between the transmit (TX) and receive (RX) pulse. The results were obtained using an experimental setup where the MEMS chip was interconnected with a customized printed circuit board (PCB) using Al wire bonds. Full article
Open AccessProceedings An Inductively Coupled Biodegradable Capacitive Pressure Sensor
Proceedings 2018, 2(13), 914; https://doi.org/10.3390/proceedings2130914
Published: 26 November 2018
Viewed by 135 | PDF Full-text (692 KB)
Abstract
A biodegradable inductively coupled pressure sensor is presented. Three sensors were fabricated using melt processed biodegradable polymers and electron-beam evaporated magnesium. All the sensors showed similar pressure responses from 0 to 0.2 bar. In addition, the responses of the sensors to temperature changes
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A biodegradable inductively coupled pressure sensor is presented. Three sensors were fabricated using melt processed biodegradable polymers and electron-beam evaporated magnesium. All the sensors showed similar pressure responses from 0 to 0.2 bar. In addition, the responses of the sensors to temperature changes and static pressure are reported. Due to the limited quality factor of the resonance sensors, single measurements were noisy. For this reason, averaging of multiple measurements was needed to achieve consistent results. Full article
Open AccessProceedings Force Spectroscopy with Quantitative On-Cantilever Force Control
Proceedings 2018, 2(13), 915; https://doi.org/10.3390/proceedings2130915
Published: 23 November 2018
Viewed by 106 | PDF Full-text (1058 KB)
Abstract
In this work we propose a method for on-cantilever force control for application in force distance (F-z) spectroscopy for intermolecular interaction sensing. In this method we perform the F-z measurements with cantilevers integrating functionalized spheres attached to them. The F-z curve is obtained
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In this work we propose a method for on-cantilever force control for application in force distance (F-z) spectroscopy for intermolecular interaction sensing. In this method we perform the F-z measurements with cantilevers integrating functionalized spheres attached to them. The F-z curve is obtained by controlling the Lorentz force acting at the cantilever free end. The intermolecular interaction forces are measured by measuring the force necessary to retract the cantilever from the surface. The required force is generated by the current passing through the cantilever. In this scenario we monitor the bending of cantilevers using optical beam deflection (OBD) method. Moreover, as deflection of the cantilever was electromagnetically controlled it was possible to calibrate the OBD response as well. Full article
Open AccessProceedings Smart Sensing Fabrics for Live Bacteria Detection
Proceedings 2018, 2(13), 916; https://doi.org/10.3390/proceedings2130916
Published: 27 November 2018
Viewed by 100 | PDF Full-text (3195 KB)
Abstract
A smart textile for live bacteria detection of antimicrobial hospital tissues is here proposed. The capacity to detect viable bacteria is based on the use of Prussian Blue (PB) as electrochromic compound, with a clear reversible change of colour from PB to Prussian
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A smart textile for live bacteria detection of antimicrobial hospital tissues is here proposed. The capacity to detect viable bacteria is based on the use of Prussian Blue (PB) as electrochromic compound, with a clear reversible change of colour from PB to Prussian White (PW) after reduction from a bacterial metabolism process. PB nanoparticles are incorporated to polyester cotton fabrics by ultrasonic deposition. After performing different tests with bacterial samples of E. coli and S. aureus, a full colour change of the textiles was observed. These smart textiles will allow to determine the self-life of the antibacterial compounds as well to improve the control of hospital infections. Full article
Open AccessProceedings The Effect of Semiconductor Morphology on the Spatial Resolution of ZnO Based Light-Addressable Potentiometric Sensors
Proceedings 2018, 2(13), 917; https://doi.org/10.3390/proceedings2130917
Published: 27 November 2018
Viewed by 103 | PDF Full-text (601 KB)
Abstract
Light-addressable potentiometric sensors (LAPS) measure ac photocurrent at electrolyte-insulator-semiconductor (EIS) and, more recently, electrolyte-semiconductor structures to produce spatiotemporal images of chemical or biological analytes, electrical potentials and impedance. One of the most important properties for LAPS is spatial resolution, which determines the smallest
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Light-addressable potentiometric sensors (LAPS) measure ac photocurrent at electrolyte-insulator-semiconductor (EIS) and, more recently, electrolyte-semiconductor structures to produce spatiotemporal images of chemical or biological analytes, electrical potentials and impedance. One of the most important properties for LAPS is spatial resolution, which determines the smallest features that can be resolved in LAPS images. In this work, the use of nanostructured ZnO for LAPS was explored. The effect of ZnO morphology on the spatial resolution was studied with a LAPS setup. The best resolution of 2 µm was achieved in ZnO films produced by aerosol-assisted chemical vapour deposition (AACVD). Full article
Open AccessProceedings Investigation of Application-Specific Thin Film Sensor Systems with Wireless Data Transmission System
Proceedings 2018, 2(13), 919; https://doi.org/10.3390/proceedings2130919
Published: 12 December 2018
PDF Full-text (608 KB)
Abstract
Thin-film-based smart telemetric sensors coated onto the surface of washers were developed for the measurement of normal forces in screw connections for industrial applications. Full article
Open AccessProceedings Fast Formation of Lipid Bilayer Membranes for Simultaneous Analysis of Molecular Transport Using Parylene Coated Chips
Proceedings 2018, 2(13), 920; https://doi.org/10.3390/proceedings2130920
Published: 23 November 2018
Viewed by 134 | PDF Full-text (710 KB)
Abstract
Artificial lipid bilayers are an essential tool to investigate channel forming proteins. A particular challenge is to study antibiotic uptake through bacterial porins requiring low volume and parallelization. Here, we present a lipid bilayer silicon chip having a Parylene-C coated silicon nitride membrane
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Artificial lipid bilayers are an essential tool to investigate channel forming proteins. A particular challenge is to study antibiotic uptake through bacterial porins requiring low volume and parallelization. Here, we present a lipid bilayer silicon chip having a Parylene-C coated silicon nitride membrane with different aperture sizes. The Parylene-C allows very fast lipid bilayer membrane fabrication, 30 to 130 s. The realization-success is very high and an average lifetime of at least 9 h was established. Furthermore, a 3D-printed holder is realized where parallel assembly of the chips, including fluid inlets for the pipetting robot, is demonstrated. Full article
Open AccessProceedings Mechanical Impedance Analysis of a Novel MEMS Photon Force Sensor
Proceedings 2018, 2(13), 921; https://doi.org/10.3390/proceedings2130921
Published: 29 November 2018
Viewed by 105 | PDF Full-text (641 KB)
Abstract
In this work we present how to describe mechanical impedance of a photon force (PF) MEMS sensor dedicated to structures’ optomechanical studies. An actuating force (photon force) is caused by the reflection and absorption of the electromagnetic radiation beam due to the radiation
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In this work we present how to describe mechanical impedance of a photon force (PF) MEMS sensor dedicated to structures’ optomechanical studies. An actuating force (photon force) is caused by the reflection and absorption of the electromagnetic radiation beam due to the radiation pressure effect. Specially designed very soft (low k-constant, ca 10–150 mN/m) cantilevers are presented. The structures integrate a Lorentz loop, which enables electromagnetic actuation. The construction with two mirrors is proposed so that parasitic thermal actuation can be neglected. The MEMS displacement is measured with the use of a laser vibrometer. The mechanical impedance model is presented using which the stiffness is calculated. As validation measurements: thermal noise and known mass adding methods are used. Full article
Open AccessProceedings Simulation of the Readout Methods for Inductively Coupled High-Frequency Resonance Sensors
Proceedings 2018, 2(13), 923; https://doi.org/10.3390/proceedings2130923
Published: 27 November 2018
Viewed by 103 | PDF Full-text (1144 KB)
Abstract
The readout methods for inductively coupled resonance sensors were simulated using a lumped element model. The purpose of the study was to analyze the readout methods at high frequencies where the self-resonance of the reader coil is likely to interfere with the measurements.
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The readout methods for inductively coupled resonance sensors were simulated using a lumped element model. The purpose of the study was to analyze the readout methods at high frequencies where the self-resonance of the reader coil is likely to interfere with the measurements. Furthermore, the changes in the reading distance cause measurement errors. This phenomenon was studied using simulation. In addition, an algorithm that compensates these errors was tested. The simulation results were in agreement with the test measurements. In addition, the tested error compensation improved the resonance frequency estimates calculated using the simulated and measured data. Full article
Open AccessProceedings Squared PMUT with Enhanced Pressure Sensitivities
Proceedings 2018, 2(13), 925; https://doi.org/10.3390/proceedings2130925
Published: 27 November 2018
Viewed by 112 | PDF Full-text (652 KB)
Abstract
This study presents a squared AlN piezoelectric micromachined ultrasonic transducer (PMUT). Using this PMUT greater level of output pressure and higher reception sensitivity has been achieved, compared with the state-of-the-art. Another outstanding characteristic for this PMUT is that it can be monolithically integrated
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This study presents a squared AlN piezoelectric micromachined ultrasonic transducer (PMUT). Using this PMUT greater level of output pressure and higher reception sensitivity has been achieved, compared with the state-of-the-art. Another outstanding characteristic for this PMUT is that it can be monolithically integrated on CMOS substrate, being remarkably advantageous in relation to the bonding method implemented until now. Full article
Open AccessProceedings Displacement Sensor with Inherent Read-Out Circuit Using Water-Gated Field Effect Transistor (WG-FET)
Proceedings 2018, 2(13), 926; https://doi.org/10.3390/proceedings2130926
Published: 26 November 2018
Viewed by 107 | PDF Full-text (903 KB)
Abstract
This paper presents, for the first time, a displacement sensor with inherent read-out circuit using an inverter built with WG-FET that has 16-nm-thick single crystalline silicon film. In WG-FET, electrical double layer (EDL) capacitances are formed at water/silicon and water/top gate interfaces. These
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This paper presents, for the first time, a displacement sensor with inherent read-out circuit using an inverter built with WG-FET that has 16-nm-thick single crystalline silicon film. In WG-FET, electrical double layer (EDL) capacitances are formed at water/silicon and water/top gate interfaces. These two capacitances and the resistance of the de-ionized (DI) water droplet build a first order RC network. Propagation delay of an inverter built with WG-FET depends on this RC constant. When the distance between top gate and silicon film changes, EDL capacitances remain the same, but resistance of the DI-water droplet changes. Accordingly, propagation delay of the inverter changes linearly with this distance. Increasing the distance from 400 µm to 1200 µm changes low-to-high propagation delay tplh of the inverter from 1.08 ms to 1.36 ms and high-to-low propagation delay tphl from 0.48 ms to 0.56 ms, which yields sensitivities of 0.35 µs/µm and 0.1 µs/µm, respectively. Full article
Open AccessProceedings Catalytic Micro Gas Sensor with Excellent Homogeneous Temperature Distribution and Low Power Consumption for Long-Term Stable Operation
Proceedings 2018, 2(13), 927; https://doi.org/10.3390/proceedings2130927
Published: 26 November 2018
Viewed by 117 | PDF Full-text (981 KB)
Abstract
This paper presents a long-term stable thermoelectric micro gas sensor with ligand linked Pt nanoparticles as catalyst. The sensor design gives an excellent homogeneous temperature distribution over the catalytic layer, an important factor for long-term stability. The sensor consumes very low power, 18
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This paper presents a long-term stable thermoelectric micro gas sensor with ligand linked Pt nanoparticles as catalyst. The sensor design gives an excellent homogeneous temperature distribution over the catalytic layer, an important factor for long-term stability. The sensor consumes very low power, 18 mW at 100 °C heater temperature. Another thermoresistive sensor is also fabricated with same material for comparative analysis. The thermoelectric sensor gives better temperature homogeneity and consumes 23% less power than thermoresistive sensor for same average temperature on the membrane. The sensor shows linear characteristics with temperature change and has significantly high Seebeck coefficient of 6.5 mV/K. The output of the sensor remains completely constant under 15,000 ppm continuous H2 gas flow for 24 h. No degradation of sensor signal for 24 h indicates no deactivation of catalytic layer over the time. The sensor is tested with 3 different amount of catalyst at 2 different operating temperatures under 6000 ppm and 15,000 ppm continuous H2 gas flow for 4 h. Sensor output is completely stable for 3 different amount of catalyst. Full article
Open AccessProceedings Study of Electrostatic Actuator Voltage Reduction with a Tri-Electrode Actuator with Varying Pull-Down Voltage
Proceedings 2018, 2(13), 928; https://doi.org/10.3390/proceedings2130928
Published: 29 November 2018
Viewed by 138 | PDF Full-text (959 KB)
Abstract
Employing a tri-electrode topology for electrostatic actuators can significantly reduce needed control voltages. The tri-electrode topology employs a perforated intermediate electrode between the MEMS structure and pull-down electrode, and provides a low voltage control for the MEMS structure. Simulations of a spring supported
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Employing a tri-electrode topology for electrostatic actuators can significantly reduce needed control voltages. The tri-electrode topology employs a perforated intermediate electrode between the MEMS structure and pull-down electrode, and provides a low voltage control for the MEMS structure. Simulations of a spring supported MEMS in a conventional electrostatic actuator offering ~4.5 µm displacement with 20 V on the pull-down electrode, were compared to the tri-electrode actuator. This study showed that the intermediate electrode can act to provide similar controlled displacement with only 1/3 and 1/4 the voltage for the cases with the pull-down electrode held fixed at 20 V and 40 V respectively. A fabricated prototype experimentally showed that the intermediate electrode can provide similar displacement control with only 1/6 the normal control voltage of an electrostatic actuator. Full article
Open AccessProceedings Classification of Sonar Targets in Air—A Neural Network Approach
Proceedings 2018, 2(13), 929; https://doi.org/10.3390/proceedings2130929
Published: 29 November 2018
Viewed by 98 | PDF Full-text (460 KB)
Abstract
Ultrasonic sonar sensors are commonly used for contactless distance measurements in application areas such as automotive and mobile robotics. They can also be used to identify and classify sound reflecting objects. In the presented work, we classify simple sonar targets of different geometric
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Ultrasonic sonar sensors are commonly used for contactless distance measurements in application areas such as automotive and mobile robotics. They can also be used to identify and classify sound reflecting objects. In the presented work, we classify simple sonar targets of different geometric shape and size. For this purpose, we built a test stand for echo measurements that facilitates defined arbitrary translation and rotation of the targets. Artificial neural networks (ANNs) with multiple hidden layers were used as classifiers and different features were evaluated. The focus was on two features that were derived from the echoes’ cross-correlation functions with their excitation chirp signals. We could distinguish different target geometries with our features and also evaluated the ANNs’ capabilities for size discrimination of targets with the same geometric shape. Full article
Open AccessProceedings Design and Optimization of a Low-Resonant-Frequency Piezoelectric MEMS Energy Harvester Based on Artificial Intelligence
Proceedings 2018, 2(13), 930; https://doi.org/10.3390/proceedings2130930
Published: 26 November 2018
Viewed by 113 | PDF Full-text (657 KB)
Abstract
In this study we propose a piezoelectric MEMS vibration energy harvester with the capability of oscillating at low (i.e., less than 200 Hz) resonant frequency. The mechanical structure of the proposed harvester is comprised of a doubly clamped cantilever with a serpentine pattern
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In this study we propose a piezoelectric MEMS vibration energy harvester with the capability of oscillating at low (i.e., less than 200 Hz) resonant frequency. The mechanical structure of the proposed harvester is comprised of a doubly clamped cantilever with a serpentine pattern associated with several discrete masses. In order to obtain the optimal physical aspects of the harvester and speed up the design process, we have utilized a deep neural network, as an artificial intelligence (AI) method. Firstly, the deep neural network was trained with 108 data samples gained from finite element modeling (FEM). Then this trained network was integrated with the genetic algorithm (GA) to optimize geometry of the harvester to enhance its performance in terms of resonant frequency and generated voltage. Our numerical results confirm that the accuracy of the network in prediction is above 90%. Consequently, by taking advantage of this efficient AI-based performance estimator, the GA is able to reduce the device operational frequency from 169 Hz to 110.5 Hz and increase its efficiency on harvested voltage from 2.5 V to 3.4 V under 0.25 g excitation. Full article
Open AccessProceedings Gold-Silver Alloy Film Based Colorful SPR Imaging Sensor with High Sensitivity for Quantitative Chemical and Biological Detection
Proceedings 2018, 2(13), 931; https://doi.org/10.3390/proceedings2130931
Published: 6 December 2018
Viewed by 85 | PDF Full-text (747 KB)
Abstract
A gold-silver alloy film based spectral surface plasmon resonance imaging (SPRi) sensor has been prepared for in-situ quantitative detection of biochemical analytes at the sensor surface. This novel sensor has lower detection cost yet higher sensitivity relative to the conventional counterpart with a
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A gold-silver alloy film based spectral surface plasmon resonance imaging (SPRi) sensor has been prepared for in-situ quantitative detection of biochemical analytes at the sensor surface. This novel sensor has lower detection cost yet higher sensitivity relative to the conventional counterpart with a gold film. Using the laboratory-made multifunctional SPR sensing platform, both the resonant color images and the resonant spectra for the Au-Ag alloy film were measured at different incident angles. The quantitative relationship between the resonant wavelength and the average hue of corresponding resonant color image was established. With this relationship the most hue-sensitive spectral range was determined. After setting the initial resonant wavelength in the hue-sensitive spectral range, the refractive-index sensitivity of the Au-Ag alloy film based SPRi sensor was measured as Δhue/Δnc = 29,879/RIU, being 8 times higher than that obtained with the gold-film SPRi sensor. The immunodetection of benzo(a)pyrene (BaP) in water was fulfilled using the Au-Ag alloy film based SPRi sensor. The average hue of the SPR color image linearly increases with increasing the BaP concentration up to C = 0.5 μg/L and the slope is Δhue/ΔC = 132.2/(μg/L). The sensor is responsive to a change of BaP concentration as low as ΔC = 0.01 μg/L. Full article
Open AccessProceedings Enabling Citizen Science with A Crowdfunded and Field Validated Smart Air Quality Monitor
Proceedings 2018, 2(13), 932; https://doi.org/10.3390/proceedings2130932
Published: 30 November 2018
Viewed by 97 | PDF Full-text (605 KB)
Abstract
This work report the preliminary results of crowdfunding/crowdsensing campaign run in Italy aimed to functional test of a smart air quality monitoring infrastructure. Design and implementation of the cooperative monitoring infrastructure are described along with details of crowdfunding campaign. Participating users received, for
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This work report the preliminary results of crowdfunding/crowdsensing campaign run in Italy aimed to functional test of a smart air quality monitoring infrastructure. Design and implementation of the cooperative monitoring infrastructure are described along with details of crowdfunding campaign. Participating users received, for a whole month, a field validated electrochemical sensors based air quality monitoring node and a companion APP capable of reporting sophisticated concentration estimations. Calibration functions are actually based on machine learning components correcting for environmental and non target gas interferences. Data gathered in the cloud allowed for evaluation of acceptability and reliability of the node as well as for mapping concentrations measurements inside city landscape through an ad-hoc GUI. Full article
Open AccessProceedings Chemiresistors Based on Bisdithiocarbamate Interlinked Gold Nanoparticles
Proceedings 2018, 2(13), 933; https://doi.org/10.3390/proceedings2130933
Published: 3 December 2018
Viewed by 74 | PDF Full-text (1028 KB)
Abstract
The assembly, structure, composition and sensing properties of novel bisdithiocarbamate based gold nanoparticle networks have been investigated. The sensing properties have been studied with vapors of toluene, 1-propanol, water, and 4-methyl-2-pentanone. We demonstrated that bisdithiocarbamates based chemiresistive sensors show sensing properties versus volatile
[...] Read more.
The assembly, structure, composition and sensing properties of novel bisdithiocarbamate based gold nanoparticle networks have been investigated. The sensing properties have been studied with vapors of toluene, 1-propanol, water, and 4-methyl-2-pentanone. We demonstrated that bisdithiocarbamates based chemiresistive sensors show sensing properties versus volatile organic compounds (VOC) comparable to thiol based composites but that they are superior in their long term stability. Full article
Open AccessProceedings Technology for SMD Packaging MOX Gas Sensors
Proceedings 2018, 2(13), 934; https://doi.org/10.3390/proceedings2130934
Published: 30 November 2018
Viewed by 109 | PDF Full-text (603 KB)
Abstract
The perspective combination of laser micromilling technology and jet (aerosol) printing technologies for ceramic MEMS producing of microhotplate in the surface mounted device (SMD) package for the metal oxide (MOX) sensor is describing. There are discusses technological and economic aspects of small-scale production
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The perspective combination of laser micromilling technology and jet (aerosol) printing technologies for ceramic MEMS producing of microhotplate in the surface mounted device (SMD) package for the metal oxide (MOX) sensor is describing. There are discusses technological and economic aspects of small-scale production of gas MOX sensors. Experiments with laser micromilling of Al2O3 ceramics confirmed possibility to produce MEMS microhotplate for MOX gas sensor in SMD package with form-factor SOT-23. Developed technology process is close to 3D prototype philosophy—rapid, simple and cheap. Full article
Open AccessProceedings H2S and NH3 Detection with Langmuir-Schaefer Monolayer Organic Field-Effect Transistors
Proceedings 2018, 2(13), 935; https://doi.org/10.3390/proceedings2130935
Published: 6 December 2018
Viewed by 91 | PDF Full-text (463 KB)
Abstract
In this work gas sensing properties of Langmuir-Schaefer monolayer organic field-effect transistors (LS OFETs) prepared from organosilicon derivative of [1]benzothieno[3,2-b][1]-benzothiophene (BTBT) have been investigated. The monolayer has been deposited using Langmuir-Schaefer method, which results in a uniform low-defect monolayer with excellent electrical performance,
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In this work gas sensing properties of Langmuir-Schaefer monolayer organic field-effect transistors (LS OFETs) prepared from organosilicon derivative of [1]benzothieno[3,2-b][1]-benzothiophene (BTBT) have been investigated. The monolayer has been deposited using Langmuir-Schaefer method, which results in a uniform low-defect monolayer with excellent electrical performance, hole mobility up to 7 × 10−2 cm2 V−1 s−1, the threshold voltage around 0 V and on-off ratio of 104. Developed sensors demonstrate a long-term stability of a half-year storage under ambient conditions. Preliminary investigations demonstrated that the LS OFETs give instantaneous response on ammonia and hydrogen sulfide at low concentrations. The results reported open new perspectives for the OFET-based gas-sensing technology. Full article
Open AccessProceedings Sensor and Embedded Control System for Liquid Crystal Implantable Eye Lens
Proceedings 2018, 2(13), 936; https://doi.org/10.3390/proceedings2130936
Published: 11 December 2018
PDF Full-text (451 KB)
Abstract
A miniature sensor and control system is developed to facilitate human eye ciliary muscle movement detection and to drive the corresponding liquid crystal based lens to create an autofocusing lens for cataract patients. The movement of the ciliary muscle is detected by a
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A miniature sensor and control system is developed to facilitate human eye ciliary muscle movement detection and to drive the corresponding liquid crystal based lens to create an autofocusing lens for cataract patients. The movement of the ciliary muscle is detected by a marker that detunes a Colpitts oscillator. The change in oscillation frequency is measured by the implantable circuit and sent to an external control unit. This external unit calculates the corresponding focal length and returns corresponding commands to the implantable system to change differential signal driving the lens. The system is built with state-of-the-art Commercial-Off-The-Shelf (C.O.T.S.) components around a miniature ultra-low power Filed Programmable Gate Array (F.P.G.A) and a hand full analog components. The system fits on a 10 mm outer diameter Printed Circuit Board (PCB), consumes less than 2.5 mW and is able to measure up to 1 mm ciliary muscle displacements. Full article
Open AccessProceedings Integration of Microresonant Sensor into a Microfluidic Platform for the Real Time Analysis of Platelets-Collagen Interaction in Flow Condition
Proceedings 2018, 2(13), 940; https://doi.org/10.3390/proceedings2130940
Published: 10 December 2018
PDF Full-text (635 KB)
Abstract
The contribution focuses on the development of microresonant sensor solution integrated in microfluidic platform for the haemostasis assessment at realistic rheological flow conditions similar to the one in blood vessels. A multi-parameter sensor performs real time analysis of interactions between immobilized collagen and
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The contribution focuses on the development of microresonant sensor solution integrated in microfluidic platform for the haemostasis assessment at realistic rheological flow conditions similar to the one in blood vessels. A multi-parameter sensor performs real time analysis of interactions between immobilized collagen and platelets. The detection and characterization of such interactions at controlled flow rates provide information to evaluate the dynamic of each step of primary haemostasis. The microresonant sensor concept was developed and is described in the contribution. Full article
Open AccessProceedings Wafer-Scale Integration for Semi-Flexible Neural Implant Miniaturization
Proceedings 2018, 2(13), 941; https://doi.org/10.3390/proceedings2130941
Published: 10 December 2018
PDF Full-text (1649 KB) | Supplementary Files
Abstract
We present a novel, wafer-based fabrication process that enables integration and assembly of electronic components, such as ASICs and decoupling capacitors, with flexible interconnects. The electronic components are fabricated in, or placed on precisely defined and closely-spaced silicon islands that are connected by
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We present a novel, wafer-based fabrication process that enables integration and assembly of electronic components, such as ASICs and decoupling capacitors, with flexible interconnects. The electronic components are fabricated in, or placed on precisely defined and closely-spaced silicon islands that are connected by interconnects embedded in parylene-based flexible thin film. This fully CMOS compatible approach uses optimized DRIE processes and an SiO2 mesh-shaped mask, allowing for the simultaneous definition of micrometer- to millimeter-sized structures without compromising the flexibility of the device. In a single fabrication flow a unique freedom in dimensions of both the flexible film and the silicon islands can be achieved making this new technique ideal for the realization of semi-flexible/foldable implantable devices, where structures of different sizes have to be combined together for the ultimate miniaturization. Full article
Open AccessProceedings Cavitation-Assisted Micromixing for Polymeric Nanoparticle Generation
Proceedings 2018, 2(13), 942; https://doi.org/10.3390/proceedings2130942
Published: 10 December 2018
PDF Full-text (784 KB)
Abstract
The high-throughput generation of polymeric nanoparticles (PNPs) with tailored size and narrow size distribution is key for applications as relevant as sensing and nanomedicine. Here we show how cavitation bubbles in a microfluidic channel can induce rapid nanoprecipitation of PNPs with user-selectable control.
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The high-throughput generation of polymeric nanoparticles (PNPs) with tailored size and narrow size distribution is key for applications as relevant as sensing and nanomedicine. Here we show how cavitation bubbles in a microfluidic channel can induce rapid nanoprecipitation of PNPs with user-selectable control. Specifically, we used two tip-electrodes perpendicular to the flow to induce electrical breakdown of a polymer solution and a miscible non-solvent. As a result, a plasma is formed causing cavitation and rapid mixing of the fluids, yielding nanoprecipitates of polymer. We demonstrated mL/min generation of PNPs with a diameter as low as 150 nm and polydispersity below 0.15. Full article
Open AccessProceedings UV/Ozone Surface Treatment for Bonding of Elastomeric COC-Based Microfluidic Devices
Proceedings 2018, 2(13), 943; https://doi.org/10.3390/proceedings2130943
Published: 11 December 2018
PDF Full-text (674 KB)
Abstract
Reliable bonding of microstructured polymer parts is one of the major challenges in industrial fabrication of microfluidic devices. In the present work, the effects of a UV/ozone surface activation on the bonding process were investigated for the combination of a commonly used thermoplastic
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Reliable bonding of microstructured polymer parts is one of the major challenges in industrial fabrication of microfluidic devices. In the present work, the effects of a UV/ozone surface activation on the bonding process were investigated for the combination of a commonly used thermoplastic cyclic olefin copolymer (COC) with an elastomeric COC (eCOC) as a new thermoplastic elastomer material. Bonding was studied using two-component injection molded parts of COC and eCOC, together with microfluidic COC chips. Surface activation and bonding process parameters were optimized and bond strengths were characterized by the wedge test method. The results showed that strong bonding of this polymer materials combination can be achieved at temperatures significantly below the bulk glass transition temperature of COC. Full article
Open AccessProceedings Novel Methodology Based on Thick Film Gas Sensors to Monitor the Hydraulic Oil Ageing
Proceedings 2018, 2(13), 944; https://doi.org/10.3390/proceedings2130944
Published: 10 December 2018
PDF Full-text (796 KB)
Abstract
A new methodology for the real time monitoring of hydraulic oil aging based on the vapor analysis using metal oxide semiconductor (MOX) gas sensors has been successfully developed. A dedicated hydraulic test bench was designed and realized to age the oil under controlled
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A new methodology for the real time monitoring of hydraulic oil aging based on the vapor analysis using metal oxide semiconductor (MOX) gas sensors has been successfully developed. A dedicated hydraulic test bench was designed and realized to age the oil under controlled condition. Gas chromatographic analyses were performed to detect oil volatile compounds (VOCs) and their concentrations at increasing oil working time. Moreover, a laboratory sensor system have been realized to test the headspace of the same samples. Both measurements highlighted a decrease of the VOCs concentrations. Full article
Open AccessProceedings 3D-Printed, Pocket-Size Diffusion Cells for Skin Permeation Investigation
Proceedings 2018, 2(13), 945; https://doi.org/10.3390/proceedings2130945
Published: 10 December 2018
PDF Full-text (718 KB)
Abstract
Here we present a novel, compact 3D-printed diffusion cell as an in vitro tool for skin permeation investigation. As proof-of-concept, a diffusion cell for studying the permeation of a model molecule (FITC-dextran, 4 kDa) through explanted mice skin is fabricated and characterized. Good
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Here we present a novel, compact 3D-printed diffusion cell as an in vitro tool for skin permeation investigation. As proof-of-concept, a diffusion cell for studying the permeation of a model molecule (FITC-dextran, 4 kDa) through explanted mice skin is fabricated and characterized. Good viability of the tissue up to 24 h incubation in the cell is demonstrated via MTT assays. The real-time diffusion of the molecule by means of fluorescence microscopy allowed the determination of its diffusivity through the skin (~2·10−10 m2/s). Our results open the door for the real-time, high-throughput and cost-effective investigation of skin in any labs. Full article
Open AccessProceedings Silver Growth on Tungsten Oxide Nanowires for Nitrogen Dioxide Sensing at Low Temperature
Proceedings 2018, 2(13), 946; https://doi.org/10.3390/proceedings2130946
Published: 11 December 2018
PDF Full-text (876 KB)
Abstract
Gas sensors produced and working at low temperatures are particularly interesting for their compatibility with temperature sensitive substrates such as flexible ones or for their use in specific environments. In this work, we present the chemical synthesis of silver nano-islands grown on ultrathin
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Gas sensors produced and working at low temperatures are particularly interesting for their compatibility with temperature sensitive substrates such as flexible ones or for their use in specific environments. In this work, we present the chemical synthesis of silver nano-islands grown on ultrathin tungsten oxide nanowires (Ag/WO3 NWs) in order to obtain sensing materials for nitrogen dioxide (NO2) detection at temperatures below 150 °C. We compare the efficiencies of NO2 gas sensing, for WO3 NWs both before and after the silver growth, by drop-casting the nanomaterials from colloidal solutions onto substrates. Interestingly, the working temperature is reduced down to 130 °C even for NO2 concentrations as low as 0.2 ppm, with a clear improvement in sensitivity in the case of the Ag/WO3 NWs. Additionally, continuous UV irradiation reduced greatly the recovery time. Full article
Open AccessProceedings A549 Cells Measurements with Optical, Impedance and Microwave Spectroscopy
Proceedings 2018, 2(13), 947; https://doi.org/10.3390/proceedings2130947
Published: 7 December 2018
PDF Full-text (729 KB)
Abstract
Lung cancer, especially lung adenocarcinoma, is one of the main causes of death worldwide. This paper reports on the real-time detection methods of human lung adenocarcinoma A549 cells. The proposed approach is based on using optical, impedance and microwave spectroscopy in an attempt
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Lung cancer, especially lung adenocarcinoma, is one of the main causes of death worldwide. This paper reports on the real-time detection methods of human lung adenocarcinoma A549 cells. The proposed approach is based on using optical, impedance and microwave spectroscopy in an attempt to develop an online tool that can be easily used for early cancer diagnostics and treatment monitoring not only in the hospital labs, but at point of care. Low power athermal electromagnetic waves as a sensing mechanism for early cancer detection showed a particular promise. The techniques were also applied to other cells, such as PC3, LL24, HLF, HACAT and DU145, to ensure selectivity of the sensors. Providing real-time information at point of care will be a significant leap on its own as it will dramatically increase screening capabilities. Full article
Open AccessProceedings Modelling and Simulation of Microplasma Discharge Device for Sterilization Applications
Proceedings 2018, 2(13), 948; https://doi.org/10.3390/proceedings2130948
Published: 3 December 2018
Viewed by 77 | PDF Full-text (788 KB)
Abstract
In this study, a microplasma discharge device (MDD) was modelled and simulated for sterilization applications. The MDD was modelled with copper and dielectric based electrodes on flexible polyethylene terephthalate substrate. COMSOL Multiphysics® simulation performed on the MDD model demonstrated varying electron density
[...] Read more.
In this study, a microplasma discharge device (MDD) was modelled and simulated for sterilization applications. The MDD was modelled with copper and dielectric based electrodes on flexible polyethylene terephthalate substrate. COMSOL Multiphysics® simulation performed on the MDD model demonstrated varying electron density and electric field distribution for AC terminal voltages ranging from 500 V to 8000 V. A variation of 14% and 54% was also observed for electron density and mobility, respectively when the temperature was increased from 240 K to 360 K, at constant pressure of 1 atm. In addition, a variation of 90% and 78% was observed for electron density and mobility, respectively when the pressure was increased from 0.3 atm to 1.3 atm, at constant room temperature of 295 K. The response of the MDD is analysed and presented in this paper. Full article
Open AccessProceedings A Gravure Printed Flexible Electrochemical Sensor for the Detection of Heavy Metal Compounds
Proceedings 2018, 2(13), 950; https://doi.org/10.3390/proceedings2130950
Published: 3 December 2018
Viewed by 123 | PDF Full-text (732 KB)
Abstract
An electrochemical sensor was fabricated on a flexible polyethylene terephthalate (PET) substrate for the detection of cadmium sulfide (CdS), a heavy metal compound. The sensor consists of a working and reference electrode that were gravure printed using silver (Ag) ink on the PET
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An electrochemical sensor was fabricated on a flexible polyethylene terephthalate (PET) substrate for the detection of cadmium sulfide (CdS), a heavy metal compound. The sensor consists of a working and reference electrode that were gravure printed using silver (Ag) ink on the PET substrate. The performance of the sensor was investigated by measuring electrical impedance spectroscopy (EIS) for varying concentrations of the CdS. From the EIS based response, an impedance change of 11 ± 1%, 23 ± 1%, 34 ± 2% and 50 ± 3% was observed for the 1 pM, 1 nM, 1 µM and 1 mM concentrations of CdS, respectively when compared to de-ionized (DI) water, thus demonstrating the potential of employing gravure printed electrochemical sensors for heavy metal detection applications. Full article
Open AccessProceedings Design, Simulation and Fabrication of A Novel MEMS Based Pulsometer
Proceedings 2018, 2(13), 951; https://doi.org/10.3390/proceedings2130951
Published: 3 December 2018
Viewed by 114 | PDF Full-text (745 KB)
Abstract
A novel pulsometer was successfully developed using microelectromechanical systems (MEMS) based silicon-on-glass (SOG) technology for biomedical applications. The sensor was modelled and simulated in COMSOL Multiphysics® for pressures ranging from 0 to 40 mmHg. The capability of the fabricated pulsometer to detect
[...] Read more.
A novel pulsometer was successfully developed using microelectromechanical systems (MEMS) based silicon-on-glass (SOG) technology for biomedical applications. The sensor was modelled and simulated in COMSOL Multiphysics® for pressures ranging from 0 to 40 mmHg. The capability of the fabricated pulsometer to detect movements in x and z-axis directions was investigated. The simulation results demonstrated displacement changes as high as of 98% and 36% in the x and z-axis directions, respectively for 40 mmHg, which correspond to typical radial blood pressure (rBP) on the wrist. In addition, an average capacitance change of 1 nF was experimentally obtained in the x-axis direction, from −5 V to 5 V. The response of the pulsometer is analyzed and presented in this paper. Full article
Open AccessProceedings Regenerable Bead-Based Microfluidic Device with integrated THIN-Film Photodiodes for Real Time Monitoring of DNA Detection
Proceedings 2018, 2(13), 953; https://doi.org/10.3390/proceedings2130953
Published: 10 December 2018
PDF Full-text (734 KB)
Abstract
Nanoporous microbead-based microfluidic systems for biosensing applications allow enhanced sensitivities, while being low cost and amenable for miniaturization. The regeneration of the microfluidic biosensing system results in a further decrease in costs while the integration of on-chip signal transduction enhances portability. Here, we
[...] Read more.
Nanoporous microbead-based microfluidic systems for biosensing applications allow enhanced sensitivities, while being low cost and amenable for miniaturization. The regeneration of the microfluidic biosensing system results in a further decrease in costs while the integration of on-chip signal transduction enhances portability. Here, we present a regenerable bead-based microfluidic device, with integrated thin-film photodiodes, for real-time monitoring of molecular recognition between a target DNA and complementary DNA (cDNA). High-sensitivity assay cycles could be performed without significant loss of probe DNA density and activity, demonstrating the potential for reusability, portability and reproducibility of the system. Full article
Open AccessProceedings Effect of Temperature and Electrical Modes on Radiation Sensitivity of MISFET Dose Sensors
Proceedings 2018, 2(13), 954; https://doi.org/10.3390/proceedings2130954
Published: 3 December 2018
Viewed by 87 | PDF Full-text (616 KB)
Abstract
The temperature and electrical modes influences on radiation sensitivity of n-channel MISFETs sensors of the total ionizing dose were investigated. There were measured the MISFET-based dosimeter output voltages V as function of the radiation doses D at const values of the drain
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The temperature and electrical modes influences on radiation sensitivity of n-channel MISFETs sensors of the total ionizing dose were investigated. There were measured the MISFET-based dosimeter output voltages V as function of the radiation doses D at const values of the drain current ID and the drain–source voltage VD, as well as the (IDVG) characteristics before, during and after irradiations at different temperatures T (VG is the gate voltage). It was shown how the conversion function V(D) and the radiation sensitivity SD are depending on the temperature T for different electrical modes. To interpret experimental data there were proposed the models taking into account the separate contributions of charges in the dielectric Qt and in SiO2–Si interface Qs. The model’s parameters ΔVt(D,T) and ΔVs(D,T) were calculated using the experimental IDVG characteristics. These models can be used to predict performances of MISFET-based devices. Full article
Open AccessProceedings An Open-Source Smart Sensor Architecture for Edge Computing in IoT Applications
Proceedings 2018, 2(13), 955; https://doi.org/10.3390/proceedings2130955
Published: 30 November 2018
Viewed by 131 | PDF Full-text (313 KB)
Abstract
Smart sensors are sensing devices that include computational and communication functionalities. In this work we present a reference model aimed at simplifying the implementation of smart sensors and their integration in IoT applications. The proposed model is micro-controller agnostic and it is viable
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Smart sensors are sensing devices that include computational and communication functionalities. In this work we present a reference model aimed at simplifying the implementation of smart sensors and their integration in IoT applications. The proposed model is micro-controller agnostic and it is viable in different scenarios ranging from the management of a single analog sensor to the orchestration of a heterogeneous array of sensors. The model is open-source and the implementation is available online as reference for the development of custom smart sensors. The evaluation of our framework shows that it can be implemented with limited overhead. Full article
Open AccessProceedings The Effect of Pt Decoration on the Gas Sensing Properties of Copper Oxide Nanorods
Proceedings 2018, 2(13), 956; https://doi.org/10.3390/proceedings2130956
Published: 10 December 2018
PDF Full-text (544 KB)
Abstract
Herein, copper oxide nanorods were hydrothermally synthesized on SiO2 substrates with inter digital gold electrodes fabricated by photolithography method. This method offers the advantage of practical usage as a sensor device. Hydrothermal synthesis were carried out at 85 °C for 4 h.
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Herein, copper oxide nanorods were hydrothermally synthesized on SiO2 substrates with inter digital gold electrodes fabricated by photolithography method. This method offers the advantage of practical usage as a sensor device. Hydrothermal synthesis were carried out at 85 °C for 4 h. Fabricated nanorods were decorated with Pt for 30 s via magnetron sputtering system. SEM, XRD and EDX studies were performed to characterize the samples. Sensing properties of nanorods were tested with H2, NO2 and CO at 200 °C. Results showed that Pt decoration enhanced sensor response to H2 while decreasing sensor response to NO2 and CO. Full article
Open AccessProceedings A Reliable and Sensitive Method Using Cyclic Voltammetry for the Detection of Airborne Fungi
Proceedings 2018, 2(13), 959; https://doi.org/10.3390/proceedings2130959
Published: 29 November 2018
Viewed by 98 | PDF Full-text (618 KB)
Abstract
Fungi are widespread throughout the environment and can cause health as well as indoor problems. One of the most common fungi involved in building damage are Aspergillus sp. This study describes a rapid method for the detection of fungal spores. It is based
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Fungi are widespread throughout the environment and can cause health as well as indoor problems. One of the most common fungi involved in building damage are Aspergillus sp. This study describes a rapid method for the detection of fungal spores. It is based on the ability of fungi to produce the enzyme cellulase, which can cleave the substrate Aminophenyl-β-d-cellobioside (APC) resulting into 4-Aminophenyl (AP). This cleavage product can then be oxidized leading to an increased output current signal. In the experimental setup several growth media and different parameters were tested over time, for instance growth conditions like pH or incubation temperature. Furthermore, various spore concentrations, which are related to the cellulase activities, were examined. This method presents a technique that makes it possible to specifically detect low concentrations of fungi spores in short time. Full article
Open AccessProceedings SCIPIO—Scientific Purification Indicator
Proceedings 2018, 2(13), 960; https://doi.org/10.3390/proceedings2130960
Published: 6 December 2018
Viewed by 90 | PDF Full-text (1054 KB)
Abstract
This paper presents a new way of dealing with drinkable water shortness all over the world. The developed devices’ functionality is based on the well-known and established SODIS (SOlar DISinfection) method. The whole device, Scipio—Scientific Purification Indicator, is designed in a way, that
[...] Read more.
This paper presents a new way of dealing with drinkable water shortness all over the world. The developed devices’ functionality is based on the well-known and established SODIS (SOlar DISinfection) method. The whole device, Scipio—Scientific Purification Indicator, is designed in a way, that it is self-powered by solar cells and can be placed inside a bottle in order to provide best measurements. The device is capable of communicate via Bluetooth with other devices. Thus, an observation or control of the correct application of the SODIS method can be established. The paradigm shift we offer in terms of development aid not to simply help the people but to empower them to care for themselves. It is a very important that everyone can purify their own drinking water without the need of subsequent supplies. Full article
Open AccessProceedings Collagenase Biosensor Based on the Degradation of Peptide Cross-Linked Poly(Ethylene Glycol) Hydrogel Films
Proceedings 2018, 2(13), 961; https://doi.org/10.3390/proceedings2130961
Published: 30 November 2018
Viewed by 107 | PDF Full-text (531 KB)
Abstract
Peptide cross-linked poly(ethylene glycol) hydrogel is a promising biomaterial that has been used widely for drug delivery and tissue engineering. However, the use of this material as a biosensor material for the detection of collagenase has not been explored. Collagenase play a key
[...] Read more.
Peptide cross-linked poly(ethylene glycol) hydrogel is a promising biomaterial that has been used widely for drug delivery and tissue engineering. However, the use of this material as a biosensor material for the detection of collagenase has not been explored. Collagenase play a key role in rheumatoid arthritis and osteoarthritis. Detection of this class of enzyme using the degradable hydrogel film format is promising as a point-of-care device for disease monitoring. In this study, a biosensor was developed based on the degradation of a peptide cross-linked poly(ethylene glycol) hydrogel film for the detection of collagenase. The hydrogel was deposited on gold-coated quartz crystals and their degradation in the presence of collagenase was monitored using a Quartz Crystal Microbalance (QCM). The biosensor was shown to respond to concentrations between 2 nM to 2000 nM with a lower detection limit of 2 nM. Full article
Open AccessProceedings Resonant Photoacoustic Gas Monitoring of Combustion Emissions
Proceedings 2018, 2(13), 962; https://doi.org/10.3390/proceedings2130962
Published: 30 November 2018
Viewed by 80 | PDF Full-text (654 KB)
Abstract
Since the entrance into the industrial era and the increasing demand for energy due to global economic growth and development, the amount of energy-related emissions have continuously grown every year to significantly high levels. Greenhouse gases like carbon dioxide, nitrous oxide or methane
[...] Read more.
Since the entrance into the industrial era and the increasing demand for energy due to global economic growth and development, the amount of energy-related emissions have continuously grown every year to significantly high levels. Greenhouse gases like carbon dioxide, nitrous oxide or methane cause an increase in the earth’s temperature. Toxic gases like nitrous oxides, Sulphur dioxide and carbon monoxide are extremely detrimental to the health of all living beings. Over the past few years, global organizations are imposing tighter limits by international laws for flue-gas emissions from fossil-fuel combustion. Emission-limiting techniques like filter and scrubber systems have to be installed for waste gas treatment in the exhaust gas streams. In addition, exhaust gas measuring technologies detect the actual emission values of the respective target gases. We present the development of a low-cost and highly sensitive photoacoustic gas detector for the monitoring of emitted combustion gases. First tests were carried out with the toxic Sulphur dioxide (SO2) in secure lab conditions, where a sensitivity below 1 part per million (ppm) was achieved during continuous flow of the gas. Full article
Open AccessProceedings On-Line Error Correction in Sensor Interface Circuits by Using Adaptive Filtering and Digital Calibration
Proceedings 2018, 2(13), 963; https://doi.org/10.3390/proceedings2130963
Published: 30 November 2018
Viewed by 98 | PDF Full-text (457 KB)
Abstract
Numerous non-ideal effects can distort the functionality of sensor interfaces and have to be considered during the design phase. In order to relax the requirements for the analog circuit components, adaptive filtering and digital calibration are used in this work to detect and
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Numerous non-ideal effects can distort the functionality of sensor interfaces and have to be considered during the design phase. In order to relax the requirements for the analog circuit components, adaptive filtering and digital calibration are used in this work to detect and correct different gain- and offset-errors. The error detection is performed by transmitting a test signal through the sensor interface continuously and in parallel to the sensor signal. In the digital domain, variations of the test signal are evaluated and present errors can be determined and eliminated. In this way, an on-line error correction is realized, which makes the sensor interface more robust against static and dynamic non-idealities. The proposed concept is demonstrated by correcting different gain- and offset-errors in a 65nm CMOS sensor interface. Full article
Open AccessProceedings Gas Sensing Properties of WO3 Nanowires Decorated with Iridium Oxide Nanoparticles
Proceedings 2018, 2(13), 964; https://doi.org/10.3390/proceedings2130964
Published: 30 November 2018
Viewed by 77 | PDF Full-text (580 KB)
Abstract
Tungsten trioxide (WO3) nanowires decorated with iridium oxide nanoparticles (WO3-IrO2) have been studied as candidate towards low NO2 concentrations gas detection. Furthermore, reducing gases such ammonia vapors and hydrogen have been also studied. WO3 nanowires
[...] Read more.
Tungsten trioxide (WO3) nanowires decorated with iridium oxide nanoparticles (WO3-IrO2) have been studied as candidate towards low NO2 concentrations gas detection. Furthermore, reducing gases such ammonia vapors and hydrogen have been also studied. WO3 nanowires were grown following an aerosol assisted chemical vapor deposition (AACVD) methodology; and decorated in two steps. As first step, nanowires were grown and subsequently annealed at 500 °C for two hours in order to remove impurities and enhance the oxidation ratio. In a second step, employing an iridium oxide nanoparticles suspension they were decorated through AACVD. Iridium oxide nanoparticles were synthetized from an inorganic precursor through an acidic hydrolysis synthesis route. The sensors were also characterized through environmental scanning electron microscopy (ESEM) and X-ray photoelectron spectroscopy (XPS). All iridium oxide based sensors shows a higher response towards all the gases tested in comparison towards pristine sensors, despite showing the best performance towards NO2. Full article
Open AccessProceedings Oil-cooled thermoelectric energy harvesting for aero-engine sensing system
Proceedings 2018, 2(13), 965; https://doi.org/10.3390/proceedings2130965
Published: 10 December 2018
PDF Full-text (3811 KB)
Abstract
To enhance the performance and reliability of aircraft propulsion systems, an integrated
bearing condition monitoring system is proposed. This intelligent bearing must have advanced health
management capabilities to provide early warning of problems. In most commercial high-temperature
applications, the sensing system is located
[...] Read more.
To enhance the performance and reliability of aircraft propulsion systems, an integrated
bearing condition monitoring system is proposed. This intelligent bearing must have advanced health
management capabilities to provide early warning of problems. In most commercial high-temperature
applications, the sensing system is located externally due to lack of appropriate electronic devices
that can function at high temperature. This paper presents the design and implementation of a
self-powered sensing system for use in a high-temperature aircraft environment. The performance of
the thermoelectric generator and energy availability to process acceleration data is shown from our
laboratory tests based on realistic operating conditions. Full article
Open AccessProceedings Evaluation of a Colorimetric Sensor System for Early Fire Detection
Proceedings 2018, 2(13), 966; https://doi.org/10.3390/proceedings2130966
Published: 5 December 2018
Viewed by 124 | PDF Full-text (323 KB)
Abstract
The use of colorimetric reactions as a sensitive, selective and low-cost method for the detection of fire related gases is evaluated in this work. As the most relevant fire gas carbon monoxide CO is addressed in the first place. A rhodium-based metal-organic complex
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The use of colorimetric reactions as a sensitive, selective and low-cost method for the detection of fire related gases is evaluated in this work. As the most relevant fire gas carbon monoxide CO is addressed in the first place. A rhodium-based metal-organic complex has been selected, which a colorimetric material sensitive for CO. For the optical readout a compact setup has been developed which provides the option for spectroscopy in transmission and attenuated total reflection in parallel. The detection of CO in concentrations relevant for fire detection has been demonstrated in synthetic gas mixtures as well as in real fire gas. Full article
Open AccessProceedings Modelling a Holographic Particle Counter
Proceedings 2018, 2(13), 967; https://doi.org/10.3390/proceedings2130967
Published: 30 November 2018
Viewed by 99 | PDF Full-text (1265 KB)
Abstract
In order to design an imaging unit of a novel holographic particle counter an aerosol particle model was developed to generate a virtual hologram plane of an aerosol volume of interest. The herein presented model combines the three essential components to help dimensioning
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In order to design an imaging unit of a novel holographic particle counter an aerosol particle model was developed to generate a virtual hologram plane of an aerosol volume of interest. The herein presented model combines the three essential components to help dimensioning a target detection unit: (i) an In-Line holography model with a reference light source and a basic transfer function of an imager to take into account imager size, pixel pitch and exposure time; (ii) an aerosol particle model with particles of variable count, size and spatial distribution; and (iii) the possibility to import fluid dynamics simulation data to simulate the particle flow in an arbitrary sampling volume. Full article
Open AccessProceedings Load-Deflection Behavior of RF-MEMS Switches: FEA and Analytical Modeling for Prediction of Mechanical Properties
Proceedings 2018, 2(13), 968; https://doi.org/10.3390/proceedings2130968
Published: 30 November 2018
Viewed by 97 | PDF Full-text (575 KB)
Abstract
SixNy/a-Si/SixNy thin film RF-MEMS switches were fabricated by unconventional PECVD process using surface micromachining approach. The mechanical properties of tri-layer were measured by nanoindentation and wafer curvature method. Deflections of switches clamped on two opposite edges
[...] Read more.
SixNy/a-Si/SixNy thin film RF-MEMS switches were fabricated by unconventional PECVD process using surface micromachining approach. The mechanical properties of tri-layer were measured by nanoindentation and wafer curvature method. Deflections of switches clamped on two opposite edges were measured by a profilometer applying increasing quasi-point pressure loads. Finite Element Analysis (FEA) was used to study the mechanical behavior of clamped-clamped switches. An analytical solution was developed and validated, numerically and experimentally, to describe the load-deflection response of perforated membranes to quasi-point loads. The proposed function was used to determine the internal stress of the investigated membranes; the relative error between the predicted and calculated stress values was in the range 2.1–8.5%. Full article
Open AccessProceedings An Analytical Method for Modelling Pull-In Effect during Anodic Bonding
Proceedings 2018, 2(13), 969; https://doi.org/10.3390/proceedings2130969
Published: 3 December 2018
Viewed by 68 | PDF Full-text (1107 KB)
Abstract
Pull-in effect is a common phenomenon during anodic bonding, a key step in the
fabrication processes of capacitive sensors and actuators. To assist the designs and fabrications of
these transducers, this paper presents an analytical method for modelling the pull-in effect during
anodic
[...] Read more.
Pull-in effect is a common phenomenon during anodic bonding, a key step in the
fabrication processes of capacitive sensors and actuators. To assist the designs and fabrications of
these transducers, this paper presents an analytical method for modelling the pull-in effect during
anodic bonding. The pull-in effect model was verified by finite element analysis and a verification
experiment respectively. The verification results indicate that the analytical method for modelling
the pull-in effect during anodic bonding is capable for predicting pull-in voltages of anodically
bonded capacitive sensors and actuators in a universal and practical manner without any additional
fabrication process. Full article
Open AccessProceedings Multicomponent Metal Oxide Nanostructures: Fabrication and Study of Core Issues to Improve Gas Sensing Performance
Proceedings 2018, 2(13), 970; https://doi.org/10.3390/proceedings2130970
Published: 30 November 2018
Viewed by 86 | PDF Full-text (399 KB)
Abstract
We have obtained and studied the sensing properties of porous titania-based nanostructures. The materials have been prepared using cost-effective techniques. The morphological and structural analyses of the prepared materials have been performed. The sensing properties of the samples have been studied towards carbon
[...] Read more.
We have obtained and studied the sensing properties of porous titania-based nanostructures. The materials have been prepared using cost-effective techniques. The morphological and structural analyses of the prepared materials have been performed. The sensing properties of the samples have been studied towards carbon monoxide. The obtained results demonstrate that the prepared structures are promising for the potential applications in the area of chemical sensors for the environmental monitoring. Full article
Open AccessProceedings An LED Platform for Micropower Gas Sensors
Proceedings 2018, 2(13), 971; https://doi.org/10.3390/proceedings2130971
Published: 30 November 2018
Viewed by 85 | PDF Full-text (1114 KB)
Abstract
We developed an integrated platform to build up conductometric sensors with controlled illumination. Our device contains a miniaturized indium gallium nitride (InGaN) LED as a light source, and a set of interdigitated electrodes (IDEs) in close contact with the LED. The sensor material
[...] Read more.
We developed an integrated platform to build up conductometric sensors with controlled illumination. Our device contains a miniaturized indium gallium nitride (InGaN) LED as a light source, and a set of interdigitated electrodes (IDEs) in close contact with the LED. The sensor material is later deposited on top of the IDE, to monitor its resistance. In this configuration, all the light emitted by the LED is collected by the sensor material, leading to a very efficient photoexcitation. We demonstrate the effectiveness of the approach building a photoactivated gas sensor based on ZnO operating with as little as 100 μW. Full article
Open AccessProceedings Microchannel Fabrication Using A Photo-Patternable Adhesive Material for Recording Conformational Changes of KcsA Channel with the Diffracted X-ray Tracking Method
Proceedings 2018, 2(13), 972; https://doi.org/10.3390/proceedings2130972
Published: 5 December 2018
Viewed by 24 | PDF Full-text (750 KB)
Abstract
Diffracted X-ray tracking (DXT) method can trace conformational changes of KcsA potassium ion channel during gating by recording position of diffraction spot from a gold nanocrystal attached to the channel as a movie. For high-resolution imaging under controlled microenvironments for KcsA channels, we
[...] Read more.
Diffracted X-ray tracking (DXT) method can trace conformational changes of KcsA potassium ion channel during gating by recording position of diffraction spot from a gold nanocrystal attached to the channel as a movie. For high-resolution imaging under controlled microenvironments for KcsA channels, we report a microfluidic device consisting of two SiN membrane windows bonded with a photo patternable adhesive material. The reduced signal-to-background ratio as well as suitable adhesive material thickness for the microchannel are discussed in the experiment at the synchrotron radiation facility. Full article
Open AccessProceedings Ultra-Low Power CMOS Readout for Resonant MEMS Strain Sensors
Proceedings 2018, 2(13), 973; https://doi.org/10.3390/proceedings2130973
Published: 11 December 2018
PDF Full-text (564 KB)
Abstract
This paper presents an ultra-low power, silicon-integrated readout for resonant MEMS strain sensors. The analogue readout implements a negative-resistance amplifier based on first-generation current conveyors (CCI) that, thanks to the reduced number of active elements, targets both low-power and low-noise. A prototype of
[...] Read more.
This paper presents an ultra-low power, silicon-integrated readout for resonant MEMS strain sensors. The analogue readout implements a negative-resistance amplifier based on first-generation current conveyors (CCI) that, thanks to the reduced number of active elements, targets both low-power and low-noise. A prototype of the circuit was implemented in a 0.18-µm technology occupying less than 0.4 mm2 and consuming only 9 µA from the 1.8-V power supply. The prototype was earliest tested by connecting it to a resonant MEMS strain resonator. Full article
Open AccessProceedings Novel Approach for Modeling an Ionic Imprinted Polymer Based SAW Sensor with COMSOL Multiphysics
Proceedings 2018, 2(13), 975; https://doi.org/10.3390/proceedings2130975
Published: 30 November 2018
Viewed by 97 | PDF Full-text (649 KB)
Abstract
Modeling a Surface Acoustic Wave (SAW) sensor response as a chemosensor and not only as just an electronic transducer was performed with COMSOL Multiphysics. For this study, the SAW’s sensing area was functionalized with an ionic imprinted polymer (IIP), designed for the selective
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Modeling a Surface Acoustic Wave (SAW) sensor response as a chemosensor and not only as just an electronic transducer was performed with COMSOL Multiphysics. For this study, the SAW’s sensing area was functionalized with an ionic imprinted polymer (IIP), designed for the selective detection of lead ions. The idea consists in subdividing the IIP into elementary blocks whose physical properties can be modified separately. Three configurations have been envisaged: the IIP before and after lead ions extraction and the non-imprinted polymer (NIP). The generation of shear-horizontal waves on LiTaO3 piezoelectric substrate is confirmed by recording the displacement amplitude versus time, according to the three space directions. The sensors sensitivity is estimated from the delays induced by the incorporation of the lead ions in the IIP layer. To the best of our knowledge, this approach has never been presented in the literature. Full article
Open AccessProceedings Self-Sustaining Square-Extensional Mode Resonator Oscillator for Mass Sensing in Liquid
Proceedings 2018, 2(13), 976; https://doi.org/10.3390/proceedings2130976
Published: 10 December 2018
PDF Full-text (599 KB)
Abstract
We present a 5.41 MHz square-extensional (SE) mode resonator in closed-loop oscillation for resonant mass sensing in the liquid phase. The resonator has been fabricated in piezoelectric thin film aluminum nitride (AlN) on silicon (Si). The strain profile of the SE mode allows
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We present a 5.41 MHz square-extensional (SE) mode resonator in closed-loop oscillation for resonant mass sensing in the liquid phase. The resonator has been fabricated in piezoelectric thin film aluminum nitride (AlN) on silicon (Si). The strain profile of the SE mode allows for higher electromechanical coupling efficiency using piezoelectric transduction to lower the motional resistance (Rm) given the expected low quality factors (Q) in liquid (136 compared to 942 in air). By locking the device into self-sustained oscillation, the minimum detectable frequency shift is reduced from 3680 ppm (open-loop in water) to 8.76 ppm (closed-loop in air). Full article
Open AccessProceedings A Disposable Inkjet-Printed Humidity and Temperature Sensor Fabricated on Paper
Proceedings 2018, 2(13), 977; https://doi.org/10.3390/proceedings2130977
Published: 10 December 2018
PDF Full-text (889 KB)
Abstract
In this work we present the development of a low-cost humidity and temperature sensing platform on paper by inkjet printing, using a commercial AgNPs conductive ink. The humidity sensing module was capable of measuring relative humidity in the range of 0–90%rH, exhibiting linear
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In this work we present the development of a low-cost humidity and temperature sensing platform on paper by inkjet printing, using a commercial AgNPs conductive ink. The humidity sensing module was capable of measuring relative humidity in the range of 0–90%rH, exhibiting linear response with minimal memory effect when returning to 0%rH baseline signal while the temperature sensor performed linearly as well in the range of 25–75°C. Process repeatability has been verified by electrical and optical characterization. Mechanical bending results highlight the platform’s capability to serve as an easy to install, flexible multi-parametric sensing platform. Full article
Open AccessProceedings Ultra Low Power Wireless Sensor Network for Pink Iguanas Monitoring
Proceedings 2018, 2(13), 978; https://doi.org/10.3390/proceedings2130978
Published: 30 November 2018
Viewed by 100 | PDF Full-text (839 KB)
Abstract
Energy management is a key issue in the design of long-lived wireless sensor networks. (WSNs). Energy is used to collect data by sensors and to communicate it to other nodes and to the gateways. The energy management procedures aim at minimizing the energy
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Energy management is a key issue in the design of long-lived wireless sensor networks. (WSNs). Energy is used to collect data by sensors and to communicate it to other nodes and to the gateways. The energy management procedures aim at minimizing the energy consumption of both the data acquisition and transmission activities. A careful design is crucial when the devices are powered by energy harvesting techniques, such as solar power. This paper describes a device architecture for a WSN node designed to monitor the habit of pink iguanas: a recently discovered species living in remote locations at the Galápagos Islands. The few individuals of this species live in a relatively small area (around 25 km2 on top of Volcano Wolf, Isla Isabela) that lacks of any available communication infrastructure. The design combines an ultra low power sleep mode and a long range communication capability that requires a very high power consumption. Full article
Open AccessProceedings Towards an Empirical Model for the Prediction of the Selectivity of Polymer Membranes
Proceedings 2018, 2(13), 979; https://doi.org/10.3390/proceedings2130979
Published: 30 November 2018
Viewed by 92 | PDF Full-text (440 KB)
Abstract
Polymer membranes are often used in combination with gas sensors for selectivity enhancement, especially with metal-oxide sensors (MOX). We report on the development of an empirical model to predict the gas separation properties of polymer membranes. This model is based on the two
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Polymer membranes are often used in combination with gas sensors for selectivity enhancement, especially with metal-oxide sensors (MOX). We report on the development of an empirical model to predict the gas separation properties of polymer membranes. This model is based on the two parameters sorption and diffusion, represented by the polar fraction of the free surface energy (SFE), and the water absorption combined with the molecule diameter based on Lennard-Jones. We measured the surface tension for a number of common fluoropolymers and used the results to determine their SFE using the graphical method developed by van Oss—Chaudhury—Good, compared them with literature data and further optimized the model. With the optimized model, combined with the information on functional groups in the polymers, we are able to predict the selectivity of polymer membranes. Full article
Open AccessProceedings Electromagnetic Sensing for Non-Destructive Real-Time Fruit Ripeness Detection: Case-Study for Automated Strawberry Picking
Proceedings 2018, 2(13), 980; https://doi.org/10.3390/proceedings2130980
Published: 10 December 2018
PDF Full-text (786 KB)
Abstract
Rapid non-destructive measurement or prediction of ripeness, quality and fungal infection in various fruits is a challenge currently affecting automation of fruit harvesting and gathering. This is especially true for delicate and difficult to store fruit such as strawberries, which are traditionally delivered
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Rapid non-destructive measurement or prediction of ripeness, quality and fungal infection in various fruits is a challenge currently affecting automation of fruit harvesting and gathering. This is especially true for delicate and difficult to store fruit such as strawberries, which are traditionally delivered directly to the customer from the farm. However, transportation of the product, often overseas, means that fruits’ condition at the time of gathering should be precisely planned. This paper reports on the initial trials of using non-invasive athermal microwave spectroscopy as a tool to assist in real-time fruit ripeness detection. The trials were conducted during June 2018 and have illustrated that the proposed method can distinguish between strawberries at different stages in ripening (R2 = 0.788, p = 0.0283). The findings support further development of the technique, which aims for integration with the Thorvald II agricultural robotic system. Full article
Open AccessProceedings An Intrinsically Pressure Insensitive Low Cost Particle Number Diluter Featuring Flow Monitoring
Proceedings 2018, 2(13), 981; https://doi.org/10.3390/proceedings2130981
Published: 10 December 2018
PDF Full-text (658 KB)
Abstract
We present a low cost Particle Number (PN) diluter including mass flow monitoring. The device consists of a commercial hypodermic needle, a High Efficiency Particulate Air (HEPA) filter. and a custom-made flow sensor. The flow sensor is used to monitor the diluter’s performance
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We present a low cost Particle Number (PN) diluter including mass flow monitoring. The device consists of a commercial hypodermic needle, a High Efficiency Particulate Air (HEPA) filter. and a custom-made flow sensor. The flow sensor is used to monitor the diluter’s performance and enable in-time replacement of the low cost elements used. Neither the sampling flow rate nor the pressure drop drastically change the dilution factor introduced by the presented device. This makes the presented device especially useful for particle number measurements at positions close to the tailpipe of internal combustion engine powered vehicles, where aggravating, fast pressure pulsations complicate correct sampling. Full article
Open AccessProceedings Epitaxial Graphene Sensors Combined with 3D Printed Microfluidic Chip for Heavy Metals Detection
Proceedings 2018, 2(13), 982; https://doi.org/10.3390/proceedings2130982
Published: 30 November 2018
Viewed by 111 | PDF Full-text (495 KB)
Abstract
Two-dimensional materials may constitute key elements in the development of a sensing platform where extremely high sensitivity is required, since even minimal chemical interaction can generate appreciable changes in the electronic state of the material. In this work, we investigate the sensing performance
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Two-dimensional materials may constitute key elements in the development of a sensing platform where extremely high sensitivity is required, since even minimal chemical interaction can generate appreciable changes in the electronic state of the material. In this work, we investigate the sensing performance of epitaxial graphene on Si-face 4H-SiC (EG/SiC) for liquid-phase detection of heavy metals (e.g., Pb). The integration of preparatory steps needed for sample conditioning is included in the sensing platform, exploiting fast prototyping using a 3D printer, which allows direct fabrication of a microfluidic chip incorporating all the features required to connect and execute the Lab-on-chip (LOC) functions. It is demonstrated that interaction of Pb2+ ions in water-based solutions with the EG enhances its conductivity exhibiting a Langmuir correlation between signal and Pb2+ concentration. Several concentrations of Pb2+ solutions ranging from 125 nM to 500 µM were analyzed showing good stability and reproducibility over time. Full article
Open AccessProceedings Ammonia Detection at Low Temperature by Tungsten Oxide Nanowires
Proceedings 2018, 2(13), 983; https://doi.org/10.3390/proceedings2130983
Published: 10 December 2018
PDF Full-text (547 KB)
Abstract
Ammonia detection at low temperatures below 150 °C is attractive to be well suited for flexible substrates in terms of thermal strain and to specific environment not allowing high temperature such as explosive one. In commercial gas sensors, tungsten trioxide is the mostly
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Ammonia detection at low temperatures below 150 °C is attractive to be well suited for flexible substrates in terms of thermal strain and to specific environment not allowing high temperature such as explosive one. In commercial gas sensors, tungsten trioxide is the mostly used semiconducting metal oxide after tin dioxide. We report herein the efficiency of tungsten trioxide nanowires deposited on rigid substrate by drop coating from colloidal solution. This study provides an interesting approach to fabricate ammonia sensors on conformable substrate with significant properties for applications in environmental monitoring devices. Full article
Open AccessProceedings Fabrication of Structured Boron-Doped Diamond Films for Electrochemical Applications
Proceedings 2018, 2(13), 984; https://doi.org/10.3390/proceedings2130984
Published: 29 November 2018
Viewed by 103 | PDF Full-text (1003 KB)
Abstract
In the present study, we introduce various technological approaches for fabrication of structured boron-doped diamond (BDD) electrodes, i.e., nanocones and nanorods which are used as working electrodes for electrochemical measurements. Structured BDD were realized either by reactive ion etching employing gold nanoclusters as
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In the present study, we introduce various technological approaches for fabrication of structured boron-doped diamond (BDD) electrodes, i.e., nanocones and nanorods which are used as working electrodes for electrochemical measurements. Structured BDD were realized either by reactive ion etching employing gold nanoclusters as the mask or by thermo-catalytically induced modification of the diamond surface. All samples were characterized in terms of surface morphology (scanning electron microscopy images), chemical composition (Raman spectroscopy) and electrochemical properties (anodic stripping voltammetry). Full article
Open AccessProceedings Iron Oxide Nanoparticle Decorated Graphene for Ultra-Sensitive Detection of Volatile Organic Compounds
Proceedings 2018, 2(13), 985; https://doi.org/10.3390/proceedings2130985
Published: 3 December 2018
Viewed by 136 | PDF Full-text (838 KB)
Abstract
It has been found that two-dimensional materials, such as graphene, can be used as remarkable gas detection platforms as even minimal chemical interactions can lead to distinct changes in electrical conductivity. In this work, epitaxially grown graphene was decorated with iron oxide nanoparticles
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It has been found that two-dimensional materials, such as graphene, can be used as remarkable gas detection platforms as even minimal chemical interactions can lead to distinct changes in electrical conductivity. In this work, epitaxially grown graphene was decorated with iron oxide nanoparticles for sensor performance tuning. This hybrid surface was used as a sensing layer to detect formaldehyde and benzene at concentrations of relevance in air quality monitoring (low parts per billion). Moreover, the time constants could be drastically reduced using a derivative sensor signal readout, allowing detection at the sampling rates desired for air quality monitoring applications. Full article
Open AccessProceedings Effect of Nanostructured Octahedral SnO2 Added with a Binary Mixture P-Type and N-Type Metal Oxide on CO Detection
Proceedings 2018, 2(13), 986; https://doi.org/10.3390/proceedings2130986
Published: 3 December 2018
Viewed by 78 | PDF Full-text (1514 KB)
Abstract
In this work, we study the effect of nanostructured octahedral SnO2 added with a binary mixture p-type and n-type metal oxide semiconductors of CuO and ZnO, on CO detection at two concentrations (100 ppm and 1000 ppm). These metal oxides (SnO2
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In this work, we study the effect of nanostructured octahedral SnO2 added with a binary mixture p-type and n-type metal oxide semiconductors of CuO and ZnO, on CO detection at two concentrations (100 ppm and 1000 ppm). These metal oxides (SnO2 and binary mixture of CuO75%/ZnO25%) are prepared in the form of a serigraphy paste and deposited on an optimized silicon micro-hotplate. The sensors can be operated at temperature of 550 °C with a low energy consumption of only 55 mW. The binary and ternary mixtures of metal oxide are operated at different working temperature to optimize their sensitivity to CO. Full article
Open AccessProceedings Soot Particle Classifications in the Context of a Resistive Sensor Study
Proceedings 2018, 2(13), 987; https://doi.org/10.3390/proceedings2130987
Published: 7 December 2018
PDF Full-text (525 KB)
Abstract
Since 2011, Euro 5b European standard limits the particle number (PN) emissions in addition to the particulate matter (PM) emissions. New thermal engines equipped vehicles have to auto-diagnose their own Diesel particulate filter (DPF) using on-board diagnostic (OBD) sensors. Accumulative resistive soot sensors
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Since 2011, Euro 5b European standard limits the particle number (PN) emissions in addition to the particulate matter (PM) emissions. New thermal engines equipped vehicles have to auto-diagnose their own Diesel particulate filter (DPF) using on-board diagnostic (OBD) sensors. Accumulative resistive soot sensors seem to be good candidates for PM measurements. The aim of this study is to bring more comprehension about soot micro-structures construction in order to link the response of such a sensor to particle size and PN concentration. The sensor sensitivity to the particle size has been studied using successively an electrostatic and an aerodynamic classification, showing the same trend. Full article
Open AccessProceedings Fast Humidity Sensors for Harsh Environment
Proceedings 2018, 2(13), 988; https://doi.org/10.3390/proceedings2130988
Published: 6 December 2018
Viewed by 68 | PDF Full-text (862 KB)
Abstract
With the application of a recently developed deposition method called initiated chemical vapor deposition (iCVD), remarkably fast responsive hydrogel thin films in the order of a few hundred nanometers were created. When in contact with humid air, the hydrogel layer extends its thickness
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With the application of a recently developed deposition method called initiated chemical vapor deposition (iCVD), remarkably fast responsive hydrogel thin films in the order of a few hundred nanometers were created. When in contact with humid air, the hydrogel layer extends its thickness manifold, which can be detected. The verification of the thickness change was realized interferometrically with a laser and a white light input source in two different implementations. The setup was designed without electric components in the vicinity of the active sensor layer and is therefore applicable in harsh and explosive environment. The achieved response time for an abrupt change of the humidity τ63 ≤ 2.5 s is about three times lower compared to one of the fastest commercially available sensors on the market. Full article
Open AccessProceedings Artificial Neural Networks for Automated Cell Quantification in Lensless LED Imaging Systems
Proceedings 2018, 2(13), 989; https://doi.org/10.3390/proceedings2130989
Published: 29 November 2018
Viewed by 107 | PDF Full-text (518 KB)
Abstract
Cell registration by artificial neural networks (ANNs) in combination with principal component analysis (PCA) has been demonstrated for cell images acquired by light emitting diode (LED)-based compact holographic microscopy. In this approach, principal component analysis was used to find the feature values from
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Cell registration by artificial neural networks (ANNs) in combination with principal component analysis (PCA) has been demonstrated for cell images acquired by light emitting diode (LED)-based compact holographic microscopy. In this approach, principal component analysis was used to find the feature values from cells and background, which would be subsequently employed as neural inputs into the artificial neural networks. Image datasets were acquired from multiple cell cultures using a lensless microscope, where the reference data was generated by a manually analyzed recording. To evaluate the developed automatic cell counter, the trained system was assessed on different data sets to detect immortalized mouse astrocytes, exhibiting a detection accuracy of ~81% compared with manual analysis. The results show that the feature values from principal component analysis and feature learning by artificial neural networks are able to provide an automatic approach on the cell detection and registration in lensless holographic imaging. Full article
Open AccessProceedings Printed 2D Proton Sensor for In-Situ Measurement in Glue Lines
Proceedings 2018, 2(13), 990; https://doi.org/10.3390/proceedings2130990
Published: 4 December 2018
Viewed by 75 | PDF Full-text (1340 KB)
Abstract
A screen printed pH sensor was developed using a PANI layer as a proton sensitive material for the in-situ measurements of matrix cross-linking. The sensor showed a linear response in a broad pH range (3–10) and had an evident cross-talk to Cl
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A screen printed pH sensor was developed using a PANI layer as a proton sensitive material for the in-situ measurements of matrix cross-linking. The sensor showed a linear response in a broad pH range (3–10) and had an evident cross-talk to Cl ions. Preliminary in-situ measurements showed a substantial signal change during the cross-linking process. Full article
Open AccessProceedings Analysis of Stochastic Time Response of Microfluidic Biosensors in the Case of Competitive Adsorption of Two Analytes
Proceedings 2018, 2(13), 991; https://doi.org/10.3390/proceedings2130991 (registering DOI)
Published: 13 December 2018
PDF Full-text (407 KB)
Abstract
A model of stochastic time response of adsorption-based microfluidic biosensors is presented, that considers the competitive adsorption-desorption process coupled with mass transfer of two analytes. By using the model we analyze the expected value of the adsorbed particles number of each analyte, which
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A model of stochastic time response of adsorption-based microfluidic biosensors is presented, that considers the competitive adsorption-desorption process coupled with mass transfer of two analytes. By using the model we analyze the expected value of the adsorbed particles number of each analyte, which determine the sensor response kinetics. The comparison with the case when only one analyte exists is used for investigation of the influence of competitive adsorption on the sensor response. The response kinetics analyzed by using the stochastic model is compared with the kinetics predicted by the deterministic response model. The results are useful for optimization of micro/nanosensors intended for detection of substances in ultra-low concentrations in complex samples. Full article
Open AccessProceedings A Novel Modular eNose System Based on Commercial MOX Sensors to Detect Low Concentrations of VOCs for Breath Gas Analysis
Proceedings 2018, 2(13), 993; https://doi.org/10.3390/proceedings2130993
Published: 30 November 2018
Viewed by 123 | PDF Full-text (980 KB)
Abstract
In this work, a new generation of eNose systems particularly suited for exhaled breath gas analysis is presented. The developed analyzer system comprises a compact modular, low volume, temperature controlled sensing chamber explicitly tested for the detection of acetone, isoprene, pentane and isopropanol.
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In this work, a new generation of eNose systems particularly suited for exhaled breath gas analysis is presented. The developed analyzer system comprises a compact modular, low volume, temperature controlled sensing chamber explicitly tested for the detection of acetone, isoprene, pentane and isopropanol. The eNose system sensing chamber consists of three compartments, each of which can contain 8 analog Metal Oxide (MOX) sensors or 10 digital MOX sensors. Additional sensors within the digital compartment allow for pressure, humidity and temperature measurements. The presented eNose system contains a sensor array with up to 30 physical sensors and provides the ability to discriminate between low VOC concentrations under dry and humid conditions. The MOX sensor signals were analyzed by pattern recognition methods. Full article
Open AccessProceedings Effect of Pt Nanoparticles on the Plasmonic and Chemoresistive Gas Sensing Properties of ZnO:Ga Film
Proceedings 2018, 2(13), 997; https://doi.org/10.3390/proceedings2130997
Published: 30 November 2018
Viewed by 129 | PDF Full-text (944 KB)
Abstract
In this paper, we used gallium doped zinc oxide (GZO) nanocrystals as novel plasmonic and chemoresistive sensors for the detection of hazardous gases including hydrogen (H2) and nitrogen dioxide (NO2). GZO nanocrystals with a tunable surface plasmon resonance in
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In this paper, we used gallium doped zinc oxide (GZO) nanocrystals as novel plasmonic and chemoresistive sensors for the detection of hazardous gases including hydrogen (H2) and nitrogen dioxide (NO2). GZO nanocrystals with a tunable surface plasmon resonance in the near infrared are obtained using a colloidal heat-up synthesis. Thanks to the strong sensitivity of the plasmon resonances to chemical and electrical changes occurring at the surface of the nanocrystals, such optical features can be used to detect the presence of toxic gases. The same material can be used also as chemoresistive sensors. The effect of Pt nanoparticles (NPs), a well-known catalyst for H2 splitting, have been studied both for the optical and chemoresistive gas response. Both thermal and blue-light (λ = 430 nm) activation were investigated. Full article
Open AccessProceedings A Precise Gas Dilutor Based on Binary Weighted Critical Flows to Create NO2 Concentrations
Proceedings 2018, 2(13), 998; https://doi.org/10.3390/proceedings2130998
Published: 7 December 2018
PDF Full-text (439 KB)
Abstract
A gas diluter based on critical orifices was built and evaluated. The gas diluter is capable of creating dilution ratios of 1:1400 at a total flow of 6.5 L/min. An extended uncertainty analysis of gas concentrations and dilution ratios according to the Guide
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A gas diluter based on critical orifices was built and evaluated. The gas diluter is capable of creating dilution ratios of 1:1400 at a total flow of 6.5 L/min. An extended uncertainty analysis of gas concentrations and dilution ratios according to the Guide to the Expression of Uncertainty in Measurement was conducted. A gas cylinder of 5.16 ppm NO2 with a relative uncertainty of 1.5% (k = 1) can be diluted down to a concentration of 3.69 ppb NO2 (dilution ratio of 1:1400) at an uncertainty of 1.9% (k = 1). The results are in good agreement with reference NO2 measurements, conducted with a chemiluminescence detector (CLD, European reference method EN14211; 2005). Full article
Open AccessProceedings Ultra-Thin Integrated ALD Al2O3 Electron-Transparent Windows for TEM Nanoreactor Applications
Proceedings 2018, 2(13), 1001; https://doi.org/10.3390/proceedings2131001
Published: 6 December 2018
Viewed by 96 | PDF Full-text (566 KB)
Abstract
This paper presents for the first time, the integration of ultra-thin (<10 nm) atomic layer deposition (ALD) aluminum oxide (Al2O3) membranes as electron transparent windows (ETWs) for transmission electron microscope (TEM) nanoreactor applications. The process was successfully implemented and
[...] Read more.
This paper presents for the first time, the integration of ultra-thin (<10 nm) atomic layer deposition (ALD) aluminum oxide (Al2O3) membranes as electron transparent windows (ETWs) for transmission electron microscope (TEM) nanoreactor applications. The process was successfully implemented and tested in a TEM. ETWs with thicknesses down to 5 and 10 nm were used to image nanoparticles (NPs) in a 120 keV TEM and 200 keV TEM respectively. Full article
Open AccessProceedings Non-Invasive Heart Beat Measurement Using Microwave Resonators
Proceedings 2018, 2(13), 1002; https://doi.org/10.3390/proceedings2131002
Published: 4 December 2018
Viewed by 89 | PDF Full-text (809 KB)
Abstract
In this paper we present the first results of our research regarding microwave biosensors for non-invasive permittivity monitoring of the human body. To detect permittivity changes, resonators are used, which alter their resonance frequency and their quality factor depending on the permittivity of
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In this paper we present the first results of our research regarding microwave biosensors for non-invasive permittivity monitoring of the human body. To detect permittivity changes, resonators are used, which alter their resonance frequency and their quality factor depending on the permittivity of the material they are placed upon. These permittivity changes may be used as indicators for the heart rate, blood pressure or glucose level. As a proof of concept, this paper focusses on designing resonators to detect the heart beat of humans in the Radial Artery, which is located in the forearm. Full article
Open AccessProceedings Rapid Non-Destructive Prediction of Water Activity in Dry-Cured Meat
Proceedings 2018, 2(13), 1003; https://doi.org/10.3390/proceedings2131003
Published: 30 November 2018
Viewed by 92 | PDF Full-text (558 KB)
Abstract
Water activity (aw) describes the amount of free water available in a matrix for growth of microbiological pathogens and spoilage flora. It is used to predict the safety of food products, and has particular importance for dry-cured meat manufacturers. Results from
[...] Read more.
Water activity (aw) describes the amount of free water available in a matrix for growth of microbiological pathogens and spoilage flora. It is used to predict the safety of food products, and has particular importance for dry-cured meat manufacturers. Results from tests on dry-cured pork (n = 83) demonstrate a high degree of correlation (R2 = 0.909) with current industry standard equipment. System accuracy at the 95% confidence interval (0.0125) is comparable with existing equipment available to industry. However, the added advantage of the microwave sensor to enable rapid and non-destructive measurement means that it could be used for day-to-day monitoring and optimization of products within the dry-cured meat value chain. This would reduce per-product operating costs and waste, in addition to facilitating recipe development (e.g., reduced salt). Full article
Open AccessProceedings Zinc Oxide Nanorods Wrapped with Ion-Imprinted Polypyrrole Polymer for Picomolar Selective and Electrochemical Detection of Mercury II Ions
Proceedings 2018, 2(13), 1004; https://doi.org/10.3390/proceedings2131004
Published: 5 December 2018
Viewed by 64 | PDF Full-text (232 KB)
Abstract
This study concerns the design of an ion-imprinted polymer (IIP) for the selective detection of mercury II ions. Compared to other electrochemical studies, the originality of this work lies to the fact that the IIP was electropolymerized on ZnO nanorods, which were themselves
[...] Read more.
This study concerns the design of an ion-imprinted polymer (IIP) for the selective detection of mercury II ions. Compared to other electrochemical studies, the originality of this work lies to the fact that the IIP was electropolymerized on ZnO nanorods, which were themselves grown on gold/diazonium modified substrates. This strategy of diazonium salt and ZnO nanorods permits to increase considerably the specific surface and thus to improve the sensor’s performances. The limit of detection (LOD) of the designed sensor was of order of 1 pM, the lowest value ever reported in literature. Full article
Open AccessProceedings A Sensor Platform for Smart Hydrogels in Biomedical Applications
Proceedings 2018, 2(13), 1006; https://doi.org/10.3390/proceedings2131006
Published: 3 December 2018
Viewed by 85 | PDF Full-text (829 KB)
Abstract
Smart hydrogels are inherently biocompatible hydrophilic three-dimensional polymer networks able to undergo a volume-phase transition in the presence of an analyte. By molecular imprinting and/or aptamer-based approaches they can be tailored for a wide range of analytes with high selectivity. In combination with
[...] Read more.
Smart hydrogels are inherently biocompatible hydrophilic three-dimensional polymer networks able to undergo a volume-phase transition in the presence of an analyte. By molecular imprinting and/or aptamer-based approaches they can be tailored for a wide range of analytes with high selectivity. In combination with the biocompatibility, this makes hydrogels very promising candidates for biomedical sensor applications. However, to date hydrogels are rarely used for that purpose as the reliable detection of their swelling state remains a challenge. Here we report on a newly developed biocompatible bending sensor platform which can be equipped with almost any smart hydrogel, thereby paving the way for biomedical applications. Full article
Open AccessProceedings Barium Strontium Titanate Humidity Sensor: Impact of Doping on the Structural and Electrical Properties
Proceedings 2018, 2(13), 1007; https://doi.org/10.3390/proceedings2131007 (registering DOI)
Published: 13 December 2018
PDF Full-text (566 KB)
Abstract
The influence of Mg2+ doping (3 mol %) on structural and humidity sensing properties of (Ba0.5,Sr0.5)TiO3 (BST) perovskite nanocomposite were studied in details. Microstructural properties revealed the particle size, surface area, and average pore volume diminished for
[...] Read more.
The influence of Mg2+ doping (3 mol %) on structural and humidity sensing properties of (Ba0.5,Sr0.5)TiO3 (BST) perovskite nanocomposite were studied in details. Microstructural properties revealed the particle size, surface area, and average pore volume diminished for doped sample. For the MgO doped BST sensor, the film resistance and total impedance are changed more than four orders of magnitude in the 20–95% RH range, while BST sensor shows three orders change. The 3 mol % MgO doped sample with maximum hysteresis of 6.1 RH% and response/recovery time of about 30/80 s exhibits faster characteristics compare to pure BST sample with 6.8 RH% hysteresis and response/recovery of 41 s and 98 s, respectively. Transduction mechanism was found based on the proton transfer and further confirmed by a Bode plot and Nyquist complex impedance plane plot. Full article
Open AccessProceedings A Quantitative Analysis of Glucose from Enhanced NIR Spectra through Linear Regression Model Coupled with Optimized Bandpass Filtering
Proceedings 2018, 2(13), 1010; https://doi.org/10.3390/proceedings2131010
Published: 3 December 2018
Viewed by 96 | PDF Full-text (560 KB)
Abstract
This study proposes a new preprocessing technique that combines Chebyshev filtering with baseline correction technique Asymmetric Least Squares (ALS) and Savitzky-Golay transformation (SGT) to improve the prediction of Glucose from near Infrared (NIR) spectra through linear regression models Partial Least Squares (PLS) and
[...] Read more.
This study proposes a new preprocessing technique that combines Chebyshev filtering with baseline correction technique Asymmetric Least Squares (ALS) and Savitzky-Golay transformation (SGT) to improve the prediction of Glucose from near Infrared (NIR) spectra through linear regression models Partial Least Squares (PLS) and Principal Component Regression (PCR). To investigate the performance of the proposed technique, a calibration model was first developed and then validated through prediction of Glucose from NIR spectra of a mixture of glucose, urea, and triacetin in a phosphate buffer solution where the component concentrations are within their physiological range in blood. Results indicate that the proposed technique improves the performance of both PLS and PCR and achieves standard error of prediction (SEP) as low as 12.76 mg/dL which is in the clinically acceptable level and comparable to the existing literature. Full article
Open AccessProceedings A Novel Device for Functional Evaluation of Gas Sensing Layers
Proceedings 2018, 2(13), 1012; https://doi.org/10.3390/proceedings2131012
Published: 3 December 2018
Viewed by 89 | PDF Full-text (1150 KB)
Abstract
Chemical gas sensors are operated at elevated temperatures and the actual temperature has a tremendous influence on sensitivity and selectivity. From that perspective, precise temperature control over the chip is an absolute requirement. Next to a stable heating system, a controlled gas flow
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Chemical gas sensors are operated at elevated temperatures and the actual temperature has a tremendous influence on sensitivity and selectivity. From that perspective, precise temperature control over the chip is an absolute requirement. Next to a stable heating system, a controlled gas flow in the test box is required. The test gases should not cool down the sensor surface too much and not be heated up by the heater. To make the material integration easy and reduce the costs for sensor platforms, often rather large sensor devices are fabricated. We demonstrate that a combined approach of thermal analysis and computational fluid dynamics enables the co-design of gas flow path and heater to archive precise temperature conditions at the sensor material and in the surrounding test gas atmosphere. Full article
Open AccessProceedings Noise Characterization of Vortex-State GMR Sensors with Different Free Layer Thicknesses
Proceedings 2018, 2(13), 1013; https://doi.org/10.3390/proceedings2131013
Published: 3 December 2018
Viewed by 73 | PDF Full-text (862 KB)
Abstract
The spin valve principle is the most prominent sensor design among giant- (GMR) and tunneling (TMR) magnetoresistive sensors. A new sensor concept with a disk shaped free layer enables the formation of a flux-closed vortex magnetization state if a certain relation of thickness
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The spin valve principle is the most prominent sensor design among giant- (GMR) and tunneling (TMR) magnetoresistive sensors. A new sensor concept with a disk shaped free layer enables the formation of a flux-closed vortex magnetization state if a certain relation of thickness to diameter is given. The low frequency noise of current-in-plane GMR sensing elements with different free layer thicknesses at different external field strengths has been measured. The measurements of the 1/f noise in external fields enabled a separation of magnetic and electric noise contributions. It has been shown that while the sensitivity is increasing with a decreasing element thickness, the pink noise contribution is increasing too. Still the detection limit at low frequencies is better in thinner free layer elements due to the higher sensitivity. Full article
Open AccessProceedings On-Glass Optoelectronic Platform for On-Chip Detection of DNA
Proceedings 2018, 2(13), 1014; https://doi.org/10.3390/proceedings2131014
Published: 3 December 2018
Viewed by 71 | PDF Full-text (678 KB)
Abstract
Lab-on-chip are analytical systems which, compared to traditional methods, offer significant reduction of sample, reagent, energy consumption and waste production. Within this framework, we report on the development and testing of an optoelectronic platform suitable for the on-chip detection of fluorescent molecules. The
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Lab-on-chip are analytical systems which, compared to traditional methods, offer significant reduction of sample, reagent, energy consumption and waste production. Within this framework, we report on the development and testing of an optoelectronic platform suitable for the on-chip detection of fluorescent molecules. The platform combines on a single glass substrate hydrogenated amorphous silicon photosensors and a long pass interferential filter. The design of the optoelectronic components has been carried out taking into account the spectral properties of the selected fluorescent molecule. We have chosen the [Ru(phen)2(dppz)]2+ which exhibits a high fluorescence when it is complexed with nucleic acids in double helix. The on-glass optoelectronic platform, coupled with a microfluidic network, has been tested in detection of double-stranded DNA (dsDNA) reaching a detection limit as low as 10 ng/µL. Full article
Open AccessProceedings Modification of Glial Attachment by Surface Nanostructuring of SU-8 Thin Films
Proceedings 2018, 2(13), 1016; https://doi.org/10.3390/proceedings2131016
Published: 19 November 2018
Viewed by 121 | PDF Full-text (615 KB)
Abstract
Various methods are currently under development to enhance the biocompatibility of neural electrodes and to minimize the reactive gliosis around the implant surface. As cells in their native microenvironment interact with 3D nanoscale topographies of the extracellular matrix, physical modification of implant surfaces
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Various methods are currently under development to enhance the biocompatibility of neural electrodes and to minimize the reactive gliosis around the implant surface. As cells in their native microenvironment interact with 3D nanoscale topographies of the extracellular matrix, physical modification of implant surfaces may provide an alternative solution to the negative tissue response by imitating the structure of the extracellular matrix, and therefore affecting the attachment and behavior of neurons and glial cells. The attachment of primary mouse astrocytes on nanostructured SU8 polymer surfaces fabricated by e-beam lithography was investigated in our study. We found that attachment of primary mouse astrocytes on silicon-SU8 surfaces is strongly influenced by the surface topography. Full article
Open AccessProceedings Silicon-Quartz Microcapillary Opto-Fluidic Platform Obtained by CMOS-Compatible Die to Wafer 200 mm Dual Bonding Process
Proceedings 2018, 2(13), 1018; https://doi.org/10.3390/proceedings2131018
Published: 13 November 2018
Viewed by 136 | PDF Full-text (900 KB)
Abstract
A composite, capillary-driven microfluidic system suitable for transmitted light microscopy of cells (e.g., red and white human blood cells) is fabricated and demonstrated. The microfluidic system consists of a microchannels network fabricated in a photo-patternable adhesive polymer on a quartz substrate, which, by
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A composite, capillary-driven microfluidic system suitable for transmitted light microscopy of cells (e.g., red and white human blood cells) is fabricated and demonstrated. The microfluidic system consists of a microchannels network fabricated in a photo-patternable adhesive polymer on a quartz substrate, which, by means of adhesive bonding, is then connected to a silicon microfluidic die (for processing of the biological sample) and quartz die (to form the imaging chamber). The entire bonding process makes use of a very low temperature budget (200 °C). In this demonstrator, the silicon die consists of microfluidic channels with transition structures to allow conveyance of fluid utilizing capillary forces from the polymer channels to the silicon channels and back to the polymer channels. Compared to existing devices, this fully integrated platform combines on the same substrate silicon microfluidic capabilities with optical system analysis, representing a portable and versatile lab-on-chip device. Full article
Open AccessProceedings Magnetic Beads Actuating and Sensing by Light Addressability
Proceedings 2018, 2(13), 1019; https://doi.org/10.3390/proceedings2131019
Published: 13 November 2018
Viewed by 108 | PDF Full-text (687 KB)
Abstract
Micro particles and nanoparticles applied in microfluidics became a popular direction to improve biochip performance. Magnetic beads are the well-studied carriers including manipulation and surface modification, which could be easily to apply in biosensor development. A new methodology combined the actuators and sensor
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Micro particles and nanoparticles applied in microfluidics became a popular direction to improve biochip performance. Magnetic beads are the well-studied carriers including manipulation and surface modification, which could be easily to apply in biosensor development. A new methodology combined the actuators and sensor in the same chip all trigged by illumination is proposed in this study. A microfluidic chip with a-Si:H layer and ITO/glass with proper operation could be used to collect magnetic beads firstly and then following the optoelectrical measurement. In the meantime, 2D images for clusters of magnetic beads can be easily achieved with the addressable illumination. This proposed platform could own the high potential for a sensor array with better sensing performance. Full article
Open AccessProceedings A Multi-Well Thin-Si LAPS and All-in-One Readout System for Ion Activity Monitor of Epithelium Cells
Proceedings 2018, 2(13), 1020; https://doi.org/10.3390/proceedings2131020
Published: 19 November 2018
Viewed by 147 | PDF Full-text (899 KB)
Abstract
To measure the ion activities of cells, an easy-access and fully-integrated system is necessary in culture room with high cleanness and easy maintenance. A new sensor structure integrated with readout system based on light-addressable potentiometric sensor (LAPS) to quantitatively monitor real-time cell activity
[...] Read more.
To measure the ion activities of cells, an easy-access and fully-integrated system is necessary in culture room with high cleanness and easy maintenance. A new sensor structure integrated with readout system based on light-addressable potentiometric sensor (LAPS) to quantitatively monitor real-time cell activity with the advantages of label free and 2D image ability is proposed. The difference of cell number and acidification could be easily observed by 2D images by means of this proposed methodology. Full article
Open AccessProceedings C3A Epithelium Cells Directly Cultured on High-Dielectric Constant Material for Light-Addressable Potentiometric Sensor
Proceedings 2018, 2(13), 1021; https://doi.org/10.3390/proceedings2131021
Published: 16 November 2018
Viewed by 122 | PDF Full-text (963 KB)
Abstract
To investigate the ion activities of cells based on light-addressable potentiometric sensor (LAPS) platform, various high-dielectric constant sensing membrane were investigated the visibility and potential issue. Three different kinds of well-proven materials in semiconductor industry, such as Si3N4, NbOx,
[...] Read more.
To investigate the ion activities of cells based on light-addressable potentiometric sensor (LAPS) platform, various high-dielectric constant sensing membrane were investigated the visibility and potential issue. Three different kinds of well-proven materials in semiconductor industry, such as Si3N4, NbOx, and TiN, are the promising sensing membranes to directly culture C3A cells. TiN and NbOx could be the potential candidate. The photocurrent and flatband voltage difference generated by acidification reaction is verified to observe by LAPS is the future. Full article
Open AccessProceedings Multi-Sensors Integration in a Human Gut-On-Chip Platform
Proceedings 2018, 2(13), 1022; https://doi.org/10.3390/proceedings2131022
Published: 13 November 2018
Viewed by 159 | PDF Full-text (514 KB)
Abstract
In the conventional culture systems in vitro, the challenging organoid approach have recently been overcome by the development of microfluidic Organ Chip models of human intestine. The potential future applications of Intestine-on-Chips in disease modelling, drug development and personalized medicine are leading research
[...] Read more.
In the conventional culture systems in vitro, the challenging organoid approach have recently been overcome by the development of microfluidic Organ Chip models of human intestine. The potential future applications of Intestine-on-Chips in disease modelling, drug development and personalized medicine are leading research to identify and investigate limitations of modern chip-based systems and to focus the attention on the gut epithelium and its specific barrier function playing a significant role in many human disorders and diseases. In this paper, we propose and discuss the importance to implement a multi-parameter analysis on an engineered platform for developing an Epithelial Gut On Chip model. Full article
Open AccessProceedings Monolithically Integrated, CMOS-Compatible SiN Photonics for Sensing Applications
Proceedings 2018, 2(13), 1023; https://doi.org/10.3390/proceedings2131023
Published: 19 November 2018
Viewed by 140 | PDF Full-text (762 KB)
Abstract
As a leading provider of sensing solutions ams AG is developing semiconductor sensors in a wide variety of fields. One of the key competences of ams AG lies in optical sensing. To widen the company’s portfolio in this field we have been developing
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As a leading provider of sensing solutions ams AG is developing semiconductor sensors in a wide variety of fields. One of the key competences of ams AG lies in optical sensing. To widen the company’s portfolio in this field we have been developing processes for fully integrated CMOS compatible photonic components based on Si3N4 in the last few years. This contribution will give an overview of the Si3N4 process as a post-processing flow for standard CMOS, some basic photonic building blocks and their properties, and an example for their use in the field of medical applications. Full article
Open AccessProceedings Reliable Compact Models for the Investigation of Acoustic High-Frequency Effects in MEMS Transducers
Proceedings 2018, 2(13), 1024; https://doi.org/10.3390/proceedings2131024
Published: 13 November 2018
Viewed by 120 | PDF Full-text (932 KB)
Abstract
We present a fully coupled multi-energy domain compact model of a MEMS microphone dedicated to the investigation of acoustic high-frequency effects affecting the device behavior. To this end, the components of the acoustic domain are described using physics-derived analytical expressions. Finite element simulations
[...] Read more.
We present a fully coupled multi-energy domain compact model of a MEMS microphone dedicated to the investigation of acoustic high-frequency effects affecting the device behavior. To this end, the components of the acoustic domain are described using physics-derived analytical expressions. Finite element simulations are employed to confirm the validity of the acoustic submodel. The differential equations governing the small-signal dynamics of the electrically actuated transducer are solved in the frequency domain with MATLAB. The full-system model is calibrated and validated with experimental data. Measurements and simulations show very good agreement, which highlights the reliability of the presented modeling approach. Full article
Open AccessProceedings Influence of Carbon Quantum Dots on the Electrical Performance of Triboelectric Generators
Proceedings 2018, 2(13), 1025; https://doi.org/10.3390/proceedings2131025
Published: 13 November 2018
Viewed by 124 | PDF Full-text (475 KB)
Abstract
In this work we investigate the triboelectric properties of Carbon Quantum Dots (CQDs) films for potential application in triboelectric generators. CQDs were deposited on silicon wafers, using spin on techniques. Device performance was estimated in sliding mode experiments, where the CQDs-surface was sliding
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In this work we investigate the triboelectric properties of Carbon Quantum Dots (CQDs) films for potential application in triboelectric generators. CQDs were deposited on silicon wafers, using spin on techniques. Device performance was estimated in sliding mode experiments, where the CQDs-surface was sliding on top of a flexible substrate. The triboelectric signal as well as the charging of capacitors, after signal rectification, was monitored as a function of time. Our results indicate that surface roughness plays a very important role in the triboelectric signal and could compensate opposite trends due to other parameters, such as the dielectric film thickness. Full article
Open AccessProceedings Design of a Photonic Crystal Defect Waveguide Biosensor Operating in Aqueous Solutions at 1.34 µm
Proceedings 2018, 2(13), 1026; https://doi.org/10.3390/proceedings2131026
Published: 14 November 2018
Viewed by 138 | PDF Full-text (660 KB)
Abstract
A two-dimensional photonic crystal defect waveguide sensor based on CMOS-compatible silicon-on-insulator technology was designed for operation in aqueous solutions at a wavelength of 1.34 µm, by the use of the 3D Plane Wave Expansion and the Finite Difference Time Domain simulation method. An
[...] Read more.
A two-dimensional photonic crystal defect waveguide sensor based on CMOS-compatible silicon-on-insulator technology was designed for operation in aqueous solutions at a wavelength of 1.34 µm, by the use of the 3D Plane Wave Expansion and the Finite Difference Time Domain simulation method. An operation under water in this wavelength regime allows for a significantly smaller propagation loss in contrast to the state-of-the-art operation wavelength of photonic crystals at 1.55 µm. The sensor working principle is label-free and based on evanescent wave sensing exploiting the local refractive index change induced by the specific binding of target molecules to a capture molecules immobilized on the surface of the phontonic crystal structure. We experimentally proved the theoretical predications of our simulations and demonstrated the sensing functionality of the photonic crystal defect waveguide using the biotin-straptavidin binding system. Full article
Open AccessProceedings 100 nm-Gap Fingers Dielectrophoresis Functionalized MOX Gas Sensor Array for Low Temperature VOCs Detection
Proceedings 2018, 2(13), 1027; https://doi.org/10.3390/proceedings2131027
Published: 13 November 2018
Viewed by 187 | PDF Full-text (692 KB)
Abstract
Present work reports the fabrication process and functional gas sensing tests of a 100 nm-gap fingers DiElectroPhoresis (DEP) functionalized MOX (Metal OXide) gas sensor array for VOCs detection at low temperature. The Internet of Things (IoT) scenario applications of the chemical sensing-enabled mobiles
[...] Read more.
Present work reports the fabrication process and functional gas sensing tests of a 100 nm-gap fingers DiElectroPhoresis (DEP) functionalized MOX (Metal OXide) gas sensor array for VOCs detection at low temperature. The Internet of Things (IoT) scenario applications of the chemical sensing-enabled mobiles or connected devices are many ranging from indoor air quality to novel breath analyser for personal healthcare monitoring. However, the commercial MOX gas sensors operate at moderate temperatures (200–400 °C) [1], and this limits the mobile and wearable gadgets market penetration. Nanogap devices may represent the alternative devices with enhanced sensitivity even at low or room temperature. A nanogap electrodes MOX gas sensor array functionalized with 5 nm average size SnO2 nanocrystals with positive dielectrophoresis technique is presented. The single sensor active area is 4 × 4 µm2. The devices exhibited about 1 order of magnitude response at 100 °C to 150 ppm of acetone. Full article
Open AccessProceedings Frequency Modulated Magnetometer Using a Double-Ended Tuning Fork Resonator
Proceedings 2018, 2(13), 1028; https://doi.org/10.3390/proceedings2131028
Published: 9 November 2018
Viewed by 164 | PDF Full-text (800 KB)
Abstract
A Lorentz force MEMS magnetometer based on a double-ended tuning fork (DETF) for out-of-plane sensing is presented here. A novel configuration using a hexagonal-shaped Lorentz force transducer is used, which simplifies the sensor configuration and improves its sensitivity. Frequency modulated devices were fabricated
[...] Read more.
A Lorentz force MEMS magnetometer based on a double-ended tuning fork (DETF) for out-of-plane sensing is presented here. A novel configuration using a hexagonal-shaped Lorentz force transducer is used, which simplifies the sensor configuration and improves its sensitivity. Frequency modulated devices were fabricated in an in-house process on silicon on insulator wafers (SOI) and then tested in vacuum. The final devices have a differential configuration and experimental characterization shows a sensitivity of 4.59 Hz/mT for a total input current (on the Lorentz bar) of 1.5 mA. Full article
Open AccessProceedings Low-Pressure Small MEMS Accelerometer Using Sigma-Delta Modulation
Proceedings 2018, 2(13), 1029; https://doi.org/10.3390/proceedings2131029
Published: 13 November 2018
Viewed by 115 | PDF Full-text (1088 KB)
Abstract
Encapsulation of MEMS accelerometers in vacuum is advantageous, since it allows integration with other sensors, leading to size and cost reduction. One technique to operate MEMS accelerometers in vacuum is the use of closed-loop Sigma-Delta modulation, which has many advantages. In this paper,
[...] Read more.
Encapsulation of MEMS accelerometers in vacuum is advantageous, since it allows integration with other sensors, leading to size and cost reduction. One technique to operate MEMS accelerometers in vacuum is the use of closed-loop Sigma-Delta modulation, which has many advantages. In this paper, the design of a vacuum encapsulated small size MEMS accelerometer (0.2 mm2) and the preliminary measured results are presented. Experimental devices were fabricated and operated in 2nd and 3rd order Sigma-Delta modulators, achieving a noise figure of 389 µg/√Hz for a bandwidth of 200 Hz and a measurement range of at least ±1 g. Full article
Open AccessProceedings Resonant Accelerometer based on Double-Ended Tuning Fork and a Force Amplification Mechanism
Proceedings 2018, 2(13), 1030; https://doi.org/10.3390/proceedings2131030
Published: 13 November 2018
Viewed by 104 | PDF Full-text (1061 KB)
Abstract
Resonant accelerometers are an alternative to amplitude modulated devices due to their higher integration capabilities, since they are encapsulated in vacuum and are stable at low pressures. Vacuum is required for some sensors (i.e., gyroscopes) but amplitude modulated accelerometers tend to be unstable
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Resonant accelerometers are an alternative to amplitude modulated devices due to their higher integration capabilities, since they are encapsulated in vacuum and are stable at low pressures. Vacuum is required for some sensors (i.e., gyroscopes) but amplitude modulated accelerometers tend to be unstable under such conditions and therefore cannot be integrated in the same package. Herewith, a device composed by double-ended tuning fork resonators (DETF) and a force amplification mechanism for sensitivity enhancement is presented. Characterization of the fabricated devices was performed, and the design was successfully validated. A sensitivity close to 80 Hz/g was experimentally measured and the DETF characterization for different driving (AC) and bias voltages (DC) is also presented. Full article
Open AccessProceedings Capillary Microvalve Actuation Using Thermal Expansion of Trapped Air Bubble
Proceedings 2018, 2(13), 1031; https://doi.org/10.3390/proceedings2131031
Published: 16 November 2018
Viewed by 130 | PDF Full-text (539 KB)
Abstract
In this study, we demonstrate a compact actuation mechanism of a silicon capillary stop microvalve, based on electrothermal expansion of a trapped air bubble in a chamber. The bubble is heated using an integrated aluminum microheater deposited on the silicon substrate above the
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In this study, we demonstrate a compact actuation mechanism of a silicon capillary stop microvalve, based on electrothermal expansion of a trapped air bubble in a chamber. The bubble is heated using an integrated aluminum microheater deposited on the silicon substrate above the air chamber. The heater occupies an area of 320 µm × 300 µm and has a resistance of 40 Ohms. By applying a 500 ms voltage pulse of 3 V amplitude we could generate a pressure sufficient to breach the capillary barrier pressure of valve, which is around 1000 Pa. Full article
Open AccessProceedings Design and Numerical Evaluation of a Highly Selective CMOS-Compatible Mid-IR Thermal Emitter/Detector Structure Using Optical Tamm-States
Proceedings 2018, 2(13), 1032; https://doi.org/10.3390/proceedings2131032
Published: 16 November 2018
Viewed by 158 | PDF Full-text (864 KB)
Abstract
In this work we propose and evaluate a concept for a selective thermal emitter suitable for monolithic on-chip integration suitable for fabrication by conventional CMOS-compatible processes. The concept is based on our recently presented work on vertical-cavity enhanced resonant thermal emission (VERTE). Here
[...] Read more.
In this work we propose and evaluate a concept for a selective thermal emitter suitable for monolithic on-chip integration suitable for fabrication by conventional CMOS-compatible processes. The concept is based on our recently presented work on vertical-cavity enhanced resonant thermal emission (VERTE). Here we present the application of this concept to a slab waveguide structure, instead of depositing extended dielectric layers forming a one-dimensional photonic crystal. We optimize the dimension by certain design considerations and geneticalgorithm optimization and demonstrate effective absorbing/emitting properties (depending on different slab heights) of such a low-cost structure by exciting so-called optical Tamm-states on the metal-dielectric interface. Full article
Open AccessProceedings A Current-Mode TransImpedance Amplifier for Capacitive Sensors
Proceedings 2018, 2(13), 1033; https://doi.org/10.3390/proceedings2131033
Published: 13 November 2018
Viewed by 114 | PDF Full-text (791 KB)
Abstract
A Current-Mode (CM) TransImpedance Amplifier (TIA) based on Second Generation Current Conveyors (CCIIs) for capacitive microsensor measurements is presented. The designed electronic interface performs a capacitance-to-voltage conversion using 3 CCIIs and 3 resistors exploiting a synchronous-demodulation technique to improve the overall detection sensitivity
[...] Read more.
A Current-Mode (CM) TransImpedance Amplifier (TIA) based on Second Generation Current Conveyors (CCIIs) for capacitive microsensor measurements is presented. The designed electronic interface performs a capacitance-to-voltage conversion using 3 CCIIs and 3 resistors exploiting a synchronous-demodulation technique to improve the overall detection sensitivity and resolution of the system. A CM-TIA solution designed at transistor level in AMS0.35 µm integrated CMOS technology with a power consumption lower than 900 µW is proposed. Experimental results obtained with a board-level prototype show linear behavior of the proposed interface circuit with a resolution up to 34.5 fF and a sensitivity up to 223 mV/nF, confirming the theoretical expectations. Full article
Open AccessProceedings Surface Plasmon Resonances in Sn: In2O3 Thin Films with Diffraction Grating
Proceedings 2018, 2(13), 1034; https://doi.org/10.3390/proceedings2131034
Published: 9 November 2018
Viewed by 118 | PDF Full-text (693 KB)
Abstract
We newly proposed transparent conductive oxide with diffraction grating structure as an excitation field of surface plasmon resonance working at near-infrared spectral region. We experimentally demonstrated the excitation of SPR using Sn-doped In2O3 films with micro-meter pitched diffraction grating. In
[...] Read more.
We newly proposed transparent conductive oxide with diffraction grating structure as an excitation field of surface plasmon resonance working at near-infrared spectral region. We experimentally demonstrated the excitation of SPR using Sn-doped In2O3 films with micro-meter pitched diffraction grating. In this study, we considered the correlation between the grating pitch and the optical reflection spectra. Reflection spectra showed clear polarization properties in infrared spectral region, and the reflection edge has also correlation with the pitch of grating. From these results, the excitation of SPR grating was successfully demonstrated and the wavelength can be tuned by changing the grating pitch in infrared region. Full article
Open AccessProceedings Biomechanical Tissue Characterisation by Force Sensitive Smart Laparoscope of Robin Heart Surgical Robot
Proceedings 2018, 2(13), 1035; https://doi.org/10.3390/proceedings2131035
Published: 14 November 2018
Viewed by 141 | PDF Full-text (1667 KB)
Abstract
Smart laparoscope device was developed and integrated into the ROBIN HEART surgery robot system. Miniaturised silicon based force sensors were developed and integrated into laparoscope tweezers for the special applications. Different sensors were applied to detect tactile information at the tip of the
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Smart laparoscope device was developed and integrated into the ROBIN HEART surgery robot system. Miniaturised silicon based force sensors were developed and integrated into laparoscope tweezers for the special applications. Different sensors were applied to detect tactile information at the tip of the laparoscope and to measure the clamping force between the tweezers. Preliminary tests were accomplished to evaluate the force and tactile signals of the integrated sensors during interventions. Tactile measurements were implemented on artificial and real animal tissues to prove the applicability of the device for biomechanical screening during Minimal Invasive Surgery. Full article
Open AccessProceedings Resonant Photoacoustic Detection of NO2 with an LED Based Sensor
Proceedings 2018, 2(13), 1036; https://doi.org/10.3390/proceedings2131036
Published: 14 November 2018
Viewed by 119 | PDF Full-text (575 KB)
Abstract
In times of steadily increasing air pollution especially in urban areas, the monitoring of nitrogen dioxide (NO2) has gained in importance and with it the search for compact, low-cost sensors. We present a novel approach to measure NO2 in sub-ppm
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In times of steadily increasing air pollution especially in urban areas, the monitoring of nitrogen dioxide (NO2) has gained in importance and with it the search for compact, low-cost sensors. We present a novel approach to measure NO2 in sub-ppm concentrations with a photoacoustic sensor utilizing a T-shaped resonance cell. An inexpensive single LED with a peak wavelength of 410 nm was used as radiation source and the acoustic detection was done with a commercial MEMS microphone. For optimal coupling of the divergent LED light into the cell, the T-shaped resonator was developed and fabricated with rapid prototyping methods. The resonator shows a acoustic Q-factor >10 while having nearly no zero gas signal. Full article
Open AccessProceedings Fabrication of AlN-Based Flexible Piezoelectric Pressure Sensor to Integrate into an Artificial Pancreas
Proceedings 2018, 2(13), 1037; https://doi.org/10.3390/proceedings2131037
Published: 9 November 2018
Viewed by 144 | PDF Full-text (499 KB)
Abstract
Present work reports the fabrication and characterization of a flexible AlN-based piezoelectric pressure sensor integrated, as insulin capsule punching detector, into an implantable artificial pancreas (AP), developed as automated treatment device for Type 1 diabetes. Ti/AlN/Ti trilayer was sputtered on a thin kapton
[...] Read more.
Present work reports the fabrication and characterization of a flexible AlN-based piezoelectric pressure sensor integrated, as insulin capsule punching detector, into an implantable artificial pancreas (AP), developed as automated treatment device for Type 1 diabetes. Ti/AlN/Ti trilayer was sputtered on a thin kapton substrate at room temperature, making the final device flexible and sensitive to the forces range of interest (0–4 N). The proposed preliminary prototype of AP comprises a refilling module, interfaced with the intestine wall, able to dock an ingestible insulin capsule. A linearly actuated needle punches the capsule to transfer the insulin to an implanted reservoir. The pressure sensor is located at the connection of the needle with the linear actuator to sense the occurred capsule punching. The sensor waveform output was processed to clearly identify the capsule punching. Full article
Open AccessProceedings Aptamer-Based QCM-Sensor for Rapid Detection of PRRS Virus
Proceedings 2018, 2(13), 1038; https://doi.org/10.3390/proceedings2131038
Published: 12 November 2018
Viewed by 259 | PDF Full-text (319 KB)
Abstract
Porcine reproductive and respiratory syndrome (PRRS) is caused by an RNA virus and has substantial economic impact on swine industry. Screening pigs for infection is the best way to prevent spreading the disease. For that purpose, we developed biosensors based on aptamers, i.e.,
[...] Read more.
Porcine reproductive and respiratory syndrome (PRRS) is caused by an RNA virus and has substantial economic impact on swine industry. Screening pigs for infection is the best way to prevent spreading the disease. For that purpose, we developed biosensors based on aptamers, i.e., short ss-DNA that can bind to porcine reproductive and respiratory syndrome virus (PRRSV). The present study, demonstrates selectivity and sensitivity of PRRSV aptamer (7R) by the means of quartz crystal microbalance (QCM) measurements. The respective results show that 7R aptamer indeed binds to samples containing around 1010 PRRSV virus particles, but not to Pseudorabies virus (PRV) and Classical swine fever virus (CSFV). Full article
Open AccessProceedings E-Skin Pressure Sensors Made by Laser Engraved PDMS Molds
Proceedings 2018, 2(13), 1039; https://doi.org/10.3390/proceedings2131039
Published: 12 November 2018
Viewed by 191 | PDF Full-text (967 KB)
Abstract
This work describes the production of electronic-skin (e-skin) piezoresistive sensors, which micro-structuration is performed using laser engraved molds. With this fabrication approach, low-cost sensors are easily produced with a tailored performance. Sensors with micro-cones and a high sensitivity of −1 kPa−1 under
[...] Read more.
This work describes the production of electronic-skin (e-skin) piezoresistive sensors, which micro-structuration is performed using laser engraved molds. With this fabrication approach, low-cost sensors are easily produced with a tailored performance. Sensors with micro-cones and a high sensitivity of −1 kPa−1 under 600 Pa are more adequate for the blood pressure wave detection, while sensors micro-structured with semi-spheres and a maximum sensitivity of −6 × 10−3 kPa−1 in a large pressure range (1.6 kPa to 100 kPa) are more suitable for robotics and functional prosthesis. Full article
Open AccessProceedings Microcontroller-Based Seat Occupancy Detection and Classification
Proceedings 2018, 2(13), 1040; https://doi.org/10.3390/proceedings2131040
Published: 13 November 2018
Viewed by 139 | PDF Full-text (581 KB)
Abstract
This paper presents a microcontroller-based measurement system to detect and confirm the presence of a subject in a chair. The system relies on a single Force Sensing Resistor (FSR), which may be arranged in the seat or backrest of the chair, that undergoes
[...] Read more.
This paper presents a microcontroller-based measurement system to detect and confirm the presence of a subject in a chair. The system relies on a single Force Sensing Resistor (FSR), which may be arranged in the seat or backrest of the chair, that undergoes a sudden resistance change when a subject/object is seated/placed over the chair. In order to distinguish between a subject and an inanimate object, the system also monitors small-signal variations of the FSR resistance caused by respiration. These resistance variations are then directly measured by a low-cost general-purpose microcontroller without using either an analogue processing stage or an analogue-to-digital converter, thus resulting in a low-cost, low-power, compact design solution. Full article
Open AccessProceedings Optical Ammonia Sensor for Continuous Bioprocess Monitoring
Proceedings 2018, 2(13), 1041; https://doi.org/10.3390/proceedings2131041
Published: 19 November 2018
Viewed by 123 | PDF Full-text (663 KB)
Abstract
We present an optical ammonia sensor suitable for bioprocess monitoring. A fluorescent dye is physically entrapped in a polyurethane hydrogel forming an emulsion system with vinylterminated polydimethylsiloxane (PDMS). The sensing layer is covered by a hydrophobic porous membrane which excludes hydrophilic substances. Ammonia,
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We present an optical ammonia sensor suitable for bioprocess monitoring. A fluorescent dye is physically entrapped in a polyurethane hydrogel forming an emulsion system with vinylterminated polydimethylsiloxane (PDMS). The sensing layer is covered by a hydrophobic porous membrane which excludes hydrophilic substances. Ammonia, diffuses through this barrier and PDMS to the protonated dye, whereby it deprotonates the dye and switches off its emission. Readout is performed with a miniaturized phase fluorimeter combined with optical fibers. Dual-lifetime referencing (DLR) acts as detection method and Egyptian blue as reference material. Full article
Open AccessProceedings Development of Gas Sensor Array based on Phthalocyanines Functionalized TiO2/ZnO Heterojunction Thin Films
Proceedings 2018, 2(13), 1042; https://doi.org/10.3390/proceedings2131042
Published: 20 November 2018
Viewed by 130 | PDF Full-text (539 KB)
Abstract
Gas sensing properties of diverse phthalocyanines functionalized TiO2/ZnO heterojunction thin films were investigated respect to a number of volatile organic compounds (VOCs) in both dark and light conditions. These studies showed that influence of heterojunction along with functionalization alter the optical
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Gas sensing properties of diverse phthalocyanines functionalized TiO2/ZnO heterojunction thin films were investigated respect to a number of volatile organic compounds (VOCs) in both dark and light conditions. These studies showed that influence of heterojunction along with functionalization alter the optical properties and gas sensing of sensors. Results show that each sensor exhibits a different pattern of relative sensitivity, and this feature can be used to discriminate among a wide range of VOCs. Full article
Open AccessProceedings Flatness Improvement of Double-Sided Magnetic Film for Narrow Gap Electromagnetic Energy Harvester
Proceedings 2018, 2(13), 1043; https://doi.org/10.3390/proceedings2131043
Published: 11 December 2018
PDF Full-text (1423 KB)
Abstract
This paper reports the design, modeling and preliminary fabrication result of the flatness improved magnetic film on a silicon structure for narrow-gap electromagnetic (EMG) vibration energy harvester (VEH). The harvester has double-sided corrugated shape silicon vibration mass with 15 µm-thick NdFeB permanent magnet.
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This paper reports the design, modeling and preliminary fabrication result of the flatness improved magnetic film on a silicon structure for narrow-gap electromagnetic (EMG) vibration energy harvester (VEH). The harvester has double-sided corrugated shape silicon vibration mass with 15 µm-thick NdFeB permanent magnet. The narrower air-gap between the magnetic film and a counter coil electrode the higher output power. While the sputtered magnetic film shows good characteristics equivalent to a bulk magnet, it hinders to reduce the air-gap because the silicon structure was curved by its high residual stress. Applying the double-sided magnet to our previous device, the curvature radius of moving mass with 15 µm-thick NdFeB film was improved from 5.3 m to 40.1 m because of the stress compensation. With the narrowed 2 µm air-gap device, the resulting simulated output power is 48 µW that is 190 times as large as previous device. Full article
Open AccessProceedings MEMS Biomimetic Superficial and Canal Neuromasts for Flow Sensing
Proceedings 2018, 2(13), 1044; https://doi.org/10.3390/proceedings2131044
Published: 12 November 2018
Viewed by 168 | PDF Full-text (589 KB)
Abstract
Neuromast sensors found in fishes detect flows around their body and are known to generate hydrodynamic awareness. This work reports the development of superficial neuromast (SN) and canal neuromast (CN) inspired MEMS flow sensors. The MEMS artificial neuromast sensors mimic the key features
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Neuromast sensors found in fishes detect flows around their body and are known to generate hydrodynamic awareness. This work reports the development of superficial neuromast (SN) and canal neuromast (CN) inspired MEMS flow sensors. The MEMS artificial neuromast sensors mimic the key features of the SN and the CN such as the shape and the mechanical properties of the cupula. In case of both SN and CN MEMS sensors, hydrogels with varying initiator concentrations were used to replicate the Young’s modulus of the biological cupula. The MEMS SN and CN sensors were experimentally characterized in steady-state and oscillatory flows respectively. Full article
Open AccessProceedings Novel Design of an Extremely Miniaturized Accelerometer Based on Quantum Tunneling Effect
Proceedings 2018, 2(13), 1045; https://doi.org/10.3390/proceedings2131045
Published: 26 November 2018
Viewed by 95 | PDF Full-text (905 KB)
Abstract
This paper presents the design of an extremely miniaturized accelerometer based on the tunneling effect. Because of its high sensitivity the tunneling effect allows the detection of smallest deflections. The aim of the novel design is a large geometric miniaturization at the lowest
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This paper presents the design of an extremely miniaturized accelerometer based on the tunneling effect. Because of its high sensitivity the tunneling effect allows the detection of smallest deflections. The aim of the novel design is a large geometric miniaturization at the lowest possible natural frequency with a nominal acceleration of +/−1 g corresponding to a deflection of +/−9.36 Å. The poly-silicon (PolySi) sensor structure with a size (L × W) of 98 µm × 85 µm is designed in a way that the main displacement operates just in one direction. To lead the sensor into operational conditions, control a constant distance between the tunneling electrodes and perform self-test actuations two electrodes are placed below the sensor structure. The tunneling tip is deposited by a focused ion beam (FIB) to provide the tunneling section with a third pad on the substrate. Within this paper the focus is on the functional implementation of the structure, the investigation of the electrostatic actuators and the deposition of the tunneling tip by the FIB. Full article
Open AccessProceedings Fast Cross-Linking-Characterization of Waveguide-Polymers on Wafers by Imaging Low-Coherence Interferometry
Proceedings 2018, 2(13), 1046; https://doi.org/10.3390/proceedings2131046
Published: 12 November 2018
Viewed by 128 | PDF Full-text (452 KB)
Abstract
This work introduces a novel method to characterize cross-linking differences in spincast polymers for waveguide applications. The method is based on a low-coherence interferometer which utilizes an imaging spectrometer to gather spatially resolved data along a line without the need for scanning. The
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This work introduces a novel method to characterize cross-linking differences in spincast polymers for waveguide applications. The method is based on a low-coherence interferometer which utilizes an imaging spectrometer to gather spatially resolved data along a line without the need for scanning. The cross-linking characterization is performed by the determination of the wavelength-dependent optical thickness. In order to do this, an algorithm to analyze the wrapped phase data and extract refractive index information is developed. Finally, the approach is tested on photo-lithographically produced samples with lateral refractive index differences in pitches of 50 μm. Full article
Open AccessProceedings A New Method to Prepare Few-Layers of Nanoclusters Decorated Graphene: Nb2O5/Graphene and Its Gas Sensing Properties
Proceedings 2018, 2(13), 1047; https://doi.org/10.3390/proceedings2131047
Published: 12 November 2018
Viewed by 160 | PDF Full-text (490 KB)
Abstract
During the last decade, due to its excellent electrical, mechanical and thermal properties of chemically modified graphene has been extensively studied for many applications, such as polymer composites, energy-related materials, biomedical applications and sensors. The aim of this work is to evaluate the
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During the last decade, due to its excellent electrical, mechanical and thermal properties of chemically modified graphene has been extensively studied for many applications, such as polymer composites, energy-related materials, biomedical applications and sensors. The aim of this work is to evaluate the gas sensing performance of niobium oxide (Nb2O5) nanoclusters deposited onto few-layers graphene powder by magneton sputtering. Two different samples were prepared by changing electrical power of deposition. The materials were deeply morphologically, structurally and chemically characterized. Finally, they were deposited onto alumina substrates and their sensing properties were investigated vs. different gases, showing good sensing performance vs. ppm concentrations of NO2 at room temperature. Full article
Open AccessProceedings High Frequency FM MEMS Accelerometer Using Piezoresistive Resonators
Proceedings 2018, 2(13), 1048; https://doi.org/10.3390/proceedings2131048
Published: 12 November 2018
Viewed by 164 | PDF Full-text (812 KB)
Abstract
A novel frequency modulated (FM) accelerometer based on piezoresistive resonators is presented. The accelerometer uses two differential resonators, connected to the accelerometer proofmass by an amplifying leverage mechanism. The piezoresistive double-mass resonators are electrostatically driven in anti-phase and the output signal is measured
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A novel frequency modulated (FM) accelerometer based on piezoresistive resonators is presented. The accelerometer uses two differential resonators, connected to the accelerometer proofmass by an amplifying leverage mechanism. The piezoresistive double-mass resonators are electrostatically driven in anti-phase and the output signal is measured piezoresistively by applying a bias current to the connecting microbeam of the double-mass resonators. Accelerometers were fabricated using SOI technology with a 5 µm device layer. Fabricated resonators show a high resonance frequency around 705 kHz and a Q-factor close to 20,000 when measured in vacuum. Preliminary measurements show a sensitivity around 0.46 Hz/g for a single resonator. Full article
Open AccessProceedings A High-Efficiency RF Harvester with Maximum Power Point Tracking
Proceedings 2018, 2(13), 1049; https://doi.org/10.3390/proceedings2131049
Published: 23 November 2018
Viewed by 130 | PDF Full-text (360 KB)
Abstract
This paper presents the implementation of a high-efficiency radiofrequency (RF) harvester, which consists of a rectenna and a maximum power point tracker (MPPT). The rectenna was characterized from −30 dBm to −10 dBm at 808 MHz, achieving an efficiency higher than 60% at
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This paper presents the implementation of a high-efficiency radiofrequency (RF) harvester, which consists of a rectenna and a maximum power point tracker (MPPT). The rectenna was characterized from −30 dBm to −10 dBm at 808 MHz, achieving an efficiency higher than 60% at −10 dBm. Experimental results also show that the rectenna can be well modelled as a Thévenin equivalent circuit, which allows the use of a simple ensuing MPPT. The complete RF harvester was tested, achieving an overall efficiency near 50% at −10 dBm. Further tests were performed powering a sensor node from a nearby antenna. Full article
Open AccessProceedings Buck Converter for Low-Power PV Modules: A Comparative Study
Proceedings 2018, 2(13), 1050; https://doi.org/10.3390/proceedings2131050
Published: 26 November 2018
Viewed by 101 | PDF Full-text (548 KB)
Abstract
Autonomous sensors that harvest energy from the environment usually employ a dc/dc converter to regulate the operating voltage of the energy transducer around its maximum power point (MPP). In this context, this work evaluates the efficiency of a buck converter when regulating the
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Autonomous sensors that harvest energy from the environment usually employ a dc/dc converter to regulate the operating voltage of the energy transducer around its maximum power point (MPP). In this context, this work evaluates the efficiency of a buck converter when regulating the operating point of two low-power photovoltaic (PV) modules subjected to different irradiance levels. The buck converter operates in burst mode (BM) and is able to transfer the energy from the PV module to a storage unit through an optimal value of the inductor current. Experimental results show that an irradiance increase can cause either an increase or a decrease of the converter efficiency. This is because the higher the irradiance, the higher both the MPP voltage and current of the PV module, which involve opposite effects in terms of the converter efficiency. Full article
Open AccessProceedings Sensor Analysis for a Modular Wearable Finger 3D Motion Tracking System
Proceedings 2018, 2(13), 1051; https://doi.org/10.3390/proceedings2131051
Published: 26 November 2018
Viewed by 93 | PDF Full-text (418 KB)
Abstract
Body motion tracking technologies are widespread in military, medical and sport fields. The work proposes a modular wireless wearable system able to detect hand fingers motion. Such system is composed by a readout unit that analyses the data and by a wearable measuring
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Body motion tracking technologies are widespread in military, medical and sport fields. The work proposes a modular wireless wearable system able to detect hand fingers motion. Such system is composed by a readout unit that analyses the data and by a wearable measuring device directly applied on the tracked finger. This device is equipped with an Inertial Motion Unit (IMU) used to track the first phalanx motion and orientation and with a stretch sensor to monitor the bending angle between the first and second phalanxes. We carried out an experimental study, which is divided in two main parts. In the first one, the transducer performance was evaluated, whereas, in the second part, we tested the capability of the overall system to recognize simple finger movements and different objects grabbed. The preliminary results pave the possibility of developing a modular device, one for each hand finger, able to recognize the grabbed object shape or detect complex gestures. Full article
Open AccessProceedings Threshold Voltage Control to Improve Energy Utilization Efficiency of a Power Management Circuit for Energy Harvesting Applications
Proceedings 2018, 2(13), 1052; https://doi.org/10.3390/proceedings2131052
Published: 21 November 2018
Viewed by 130 | PDF Full-text (448 KB)
Abstract
This work presents a design approach that improves power management circuit (PMC) for energy harvesting applications so that more of the harvested energy can be utilized by the wireless sensor nodes (WSNs) to perform useful tasks. The proposed method is widely applicable to
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This work presents a design approach that improves power management circuit (PMC) for energy harvesting applications so that more of the harvested energy can be utilized by the wireless sensor nodes (WSNs) to perform useful tasks. The proposed method is widely applicable to different circuits by setting an appropriate threshold voltage at the energy flow control interface of the circuit. Experimental results show that with a threshold voltage difference of around 20 mV, the energy output from the PMC can differ by more than 5%. This difference is significant over a long period of time as more tasks can be performed by the WSN with the extra energy. Full article
Open AccessProceedings On-Chip Temperature Compensation for Thermal Impedance Sensors
Proceedings 2018, 2(13), 1053; https://doi.org/10.3390/proceedings2131053
Published: 27 November 2018
Viewed by 110 | PDF Full-text (509 KB)
Abstract
Electrical impedance spectroscopy is a widespread characterization method for solids or fluids in industrial applications. We here report on its thermal equivalent, the “thermal impedance spectroscopy”, improved by using a temperature compensation method for temperature dependent thermal measurements using an on-chip reference resistor.
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Electrical impedance spectroscopy is a widespread characterization method for solids or fluids in industrial applications. We here report on its thermal equivalent, the “thermal impedance spectroscopy”, improved by using a temperature compensation method for temperature dependent thermal measurements using an on-chip reference resistor. Full article
Open AccessProceedings High Throughput Roll-to-Roll Production of Microfluidic Chips
Proceedings 2018, 2(13), 1054; https://doi.org/10.3390/proceedings2131054
Published: 4 December 2018
Viewed by 102 | PDF Full-text (494 KB)
Abstract
A high throughput manufacturing process of microfluidic chips based on Roll-to-Roll imprinting is presented. With this procedure, microfluidic patterns can be produced on large area polymer substrates. The subsequent steps of inlet drilling, bonding and electrode printing are set-up on large area processes,
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A high throughput manufacturing process of microfluidic chips based on Roll-to-Roll imprinting is presented. With this procedure, microfluidic patterns can be produced on large area polymer substrates. The subsequent steps of inlet drilling, bonding and electrode printing are set-up on large area processes, too. Overall, this strategy allows highly parallelized processing of large numbers of chips—all costly steps of individual chip handling are avoided. The chips were used for the characterization of inorganic ions for soil nutrient analysis. Full article
Open AccessProceedings Investigating Intense Rainfall Influence on Distance Measurement with a Time-of-Flight Camera Sensor Using Optical Ray-Tracing Simulation Technique
Proceedings 2018, 2(13), 1056; https://doi.org/10.3390/proceedings2131056
Published: 20 November 2018
Viewed by 114 | PDF Full-text (1279 KB)
Abstract
Robust, fast and reliable examination of the surroundings is essential for further advancements in autonomous driving and robotics. Time-of-Flight (ToF) camera sensors are a key technology to measure surrounding objects and their distances on a pixel basis in real-time. Environmental effects, like rain
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Robust, fast and reliable examination of the surroundings is essential for further advancements in autonomous driving and robotics. Time-of-Flight (ToF) camera sensors are a key technology to measure surrounding objects and their distances on a pixel basis in real-time. Environmental effects, like rain in front of the sensor, can influence the distance accuracy of the sensor. Here we use an optical ray-tracing based procedure to examine the rain effect on the ToF image. Simulation results are presented for experimental rain droplet distributions, characteristic of intense rainfall at rates of 25 mm/h and 100 mm/h. The ray-tracing based simulation data and results serve as an input for developing and testing rain signal suppression strategies. Full article
Open AccessProceedings Embroidery Textile Moisture Sensor
Proceedings 2018, 2(13), 1057; https://doi.org/10.3390/proceedings2131057
Published: 21 November 2018
Viewed by 146 | PDF Full-text (1020 KB)
Abstract
In this work, two embroidered textile moisture sensors are presented. The sensors are based on a capacitive interdigitated structure embroidered on a cotton substrate with an embroidery conductor yarn composed by 99% pure silver plated nylon yarn 140/17 dtex. In order to evaluate
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In this work, two embroidered textile moisture sensors are presented. The sensors are based on a capacitive interdigitated structure embroidered on a cotton substrate with an embroidery conductor yarn composed by 99% pure silver plated nylon yarn 140/17 dtex. In order to evaluate the sensor sensitivity, the impedance of the sensor has been measured by means of a LCR meter from 20 Hz to 20 kHz on a climatic chamber with a sweep of the relative humidity from 25% to 65% at 20 °C. The experimental results show a clear and controllable dependence of the sensor impedance with the relative humidity. Therefore, this dependence points out the usefulness of the proposed sensor to develop wearable applications on health and fitness scope. Full article
Open AccessProceedings Low-Frequency Piezoelectric Accelerometer Array for Fully Implantable Cochlear Implants
Proceedings 2018, 2(13), 1059; https://doi.org/10.3390/proceedings2131059
Published: 26 November 2018
Viewed by 102 | PDF Full-text (780 KB)
Abstract
We demonstrate a low-volume, stress-free, piezoelectric micro-electromechanical system (MEMS) cantilever array for fully implantable hearing aids. The 12-element spiral-matrix is sensitive to the lower part of audible frequency range (300–700 Hz) through the proper resonant frequency of the individual spirals tuned by dimensions
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We demonstrate a low-volume, stress-free, piezoelectric micro-electromechanical system (MEMS) cantilever array for fully implantable hearing aids. The 12-element spiral-matrix is sensitive to the lower part of audible frequency range (300–700 Hz) through the proper resonant frequency of the individual spirals tuned by dimensions of the cantilevers. The obtained high Q-factors (117–254) provide high frequency selectivity. The generated open circuit voltage signals could be sufficient for the direct analog conversion of the signals for cochlear multielectrode implants. By comparing different geometries we have also demonstrated that the initial stress, which is derived from silicon-dioxide (SiO2) and aluminum-nitride (AlN) layers, could be drastically reduced simply by the spiral geometry. The results of vibration measurements have shown a good agreement with the calculated resonant frequencies. Full article
Open AccessProceedings PDMS-Au/Ag Nanocomposite Films as Highly Sensitive SERS Substrates
Proceedings 2018, 2(13), 1060; https://doi.org/10.3390/proceedings2131060
Published: 26 November 2018
Viewed by 121 | PDF Full-text (863 KB)
Abstract
Polydimethylsiloxane (PDMS)–gold/silver nanoparticle composite films were synthetized in situ by using a simple method, which is based on the reduction of chloroauric acid (HAuCl4) or silver nitrate solution (AgNO3) by the PDMS membrane. A method to monitor the development
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Polydimethylsiloxane (PDMS)–gold/silver nanoparticle composite films were synthetized in situ by using a simple method, which is based on the reduction of chloroauric acid (HAuCl4) or silver nitrate solution (AgNO3) by the PDMS membrane. A method to monitor the development of the plasmonic absorbance peak in situ (during the synthesis of the nanoparticles) is introduced in order to provide a convenient way to investigate the effect of the technological parameters on the position of the resulting peak. The resulting composite films were tested as SERS substrates at two excitation wavelengths (488 nm, 785 nm) and the preliminary results indicate that they are promising candidates for this application, with high sensitivities accompanied by cheap fabrication costs. Full article
Open AccessProceedings Discrimination of Quality and Geographical Origin of Extra Virgin Olive Oil by S3 Device with Metal Oxides Gas Sensors
Proceedings 2018, 2(13), 1061; https://doi.org/10.3390/proceedings2131061
Published: 26 November 2018
Viewed by 108 | PDF Full-text (361 KB)
Abstract
In the present work, a gas sensor device S3 based on an array of eight metal oxides semiconductor gas sensors has been demonstrated and applied to the discrimination of quality and geographical origins of the Italian extra virgin olive oils. Furthermore, the principal
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In the present work, a gas sensor device S3 based on an array of eight metal oxides semiconductor gas sensors has been demonstrated and applied to the discrimination of quality and geographical origins of the Italian extra virgin olive oils. Furthermore, the principal component analysis (PCA) and artificial neural networks (ANN) were carried out on the set of data acquired from the sensor array response to the extra virgin olive oil headspace. The preliminary results have shown a good capability of the instrument to distinguish different kind of extra virgin olive oil samples and thus evaluate their quality and origin. Full article
Open AccessProceedings Laser Driver and Analysis Circuitry Development for Quartz-Enhanced Photoacoustic Spectroscopy of NO2 for IoT Purpose
Proceedings 2018, 2(13), 1062; https://doi.org/10.3390/proceedings2131062
Published: 22 November 2018
Viewed by 230 | PDF Full-text (578 KB)
Abstract
The rising effort to track local air pollution measurements require low-cost air quality sensors that provide good accuracy, long-term stability and possibly Internet of Things (IoT) connectivity. To provide such a solution and avoid cost-intensive equipment the development of a low-cost environmental sensor
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The rising effort to track local air pollution measurements require low-cost air quality sensors that provide good accuracy, long-term stability and possibly Internet of Things (IoT) connectivity. To provide such a solution and avoid cost-intensive equipment the development of a low-cost environmental sensor system was started. To measure the pollutant NO2, a quartz-enhanced photoacoustic spectroscopy (QEPAS) setup was established. A pulsed 450 nm laser diode excites NO2 molecules due to its strong absorption at this wavelength and causes a vibrational-translational relaxation, which results in an acoustic wave. The acoustic wave is detected by a quartz tuning fork (QTF) which generates a weak electrical signal proportional to the NO2 concentration. To realize this at low cost, a laser driver and an analysis circuit including a lock-in amplifier and analog-to-digital conversion were developed. We present first results, which proof the functionality of the circuitry compared to a more expensive laboratory setup. Full article
Open AccessProceedings Loop Antenna Driven Double Microwave Resonator-Based Sensors Incorporating PDMS Microchannels on Glass Substrates
Proceedings 2018, 2(13), 1064; https://doi.org/10.3390/proceedings2131064
Published: 16 November 2018
Viewed by 135 | PDF Full-text (845 KB)
Abstract
Microwave resonator-based sensors offer low-cost, contactless, label-free sensing solutions in a variety of applications. Sensing is done by the observation of the shifts in resonant frequency of the sensor structure, which depends on resonator geometry, material and physical properties of the environment. It
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Microwave resonator-based sensors offer low-cost, contactless, label-free sensing solutions in a variety of applications. Sensing is done by the observation of the shifts in resonant frequency of the sensor structure, which depends on resonator geometry, material and physical properties of the environment. It is observed that the readings can be significantly affected by changes in secondary physical parameters or sample localization on resonator. A double microwave resonator sensing system incorporating microchannels on glass substrates are proposed to address these challenges. PDMS microchannels bonded on glass substrates are mounted on split ring resonators fabricated via low-cost processes. Experiments are performed with glucose solutions of 1.4 mg/mL–3.0 mg/mL concentration range. Results confirm that the use of double resonators increase rejection of background noise, whereas microchannel use increases measurement stability. Overall measurement sensitivity is shown to be 0.92 MHz/(mg/mL). Further improvements are aimed with the bonding of microchannels directly on resonators fabricated on glass substrates. Full article
Open AccessProceedings A Planar Electrochromic Device using WO3 Nanoparticles and a Modified Paper-Based Electrolyte
Proceedings 2018, 2(13), 1065; https://doi.org/10.3390/proceedings2131065
Published: 19 November 2018
Viewed by 141 | PDF Full-text (409 KB)
Abstract
Electrochromic devices are increasing its interest in the last decades due to the wide range of applications, from smart windows to biosensors or from smart labels to super-capacitors. So, the development of simple and cost-effective production technologies based on solution process and mask
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Electrochromic devices are increasing its interest in the last decades due to the wide range of applications, from smart windows to biosensors or from smart labels to super-capacitors. So, the development of simple and cost-effective production technologies based on solution process and mask less approach is of great interest. In this work, a new planar and flexible electrochromic device based on tungsten oxide (WO3) nanoparticles with a paper-based modified electrolyte was successfully produced, using a CO2 laser technology for electrodes patterning and hydrothermal synthesis for the nanoparticles production. The devices were fabricated with a paper pad inserted in the sensor area for hydration on time of usage, thus replacing the electrolyte material of a typical electrochromic structure with a multi-layer stack, eliminating leakage problems, easy integration with other devices and enhancing the shelf life of the devices to several months. The produced device presents a low power consumption of only 2.86 μA·cm−2, with a deep blue color and an initial charge modulation of 11.5. Full article
Open AccessProceedings Towards 3D Confocal Imaging with Laser-Machined Micro-Scanner
Proceedings 2018, 2(13), 1067; https://doi.org/10.3390/proceedings2131067
Published: 23 November 2018
Viewed by 105 | PDF Full-text (792 KB)
Abstract
A micro-scanner made of stainless-steel is fabricated via laser cutting technology for 3D Lissajous confocal imaging. The multi-gimbaled structure of the device provides two orthogonal torsional modes and three different out-of-plane modes. Torsional modes can be used to achieve 2D scan and all
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A micro-scanner made of stainless-steel is fabricated via laser cutting technology for 3D Lissajous confocal imaging. The multi-gimbaled structure of the device provides two orthogonal torsional modes and three different out-of-plane modes. Torsional modes can be used to achieve 2D scan and all of the out-of-plane modes can be used in changing the focus of the micro-scanner to achieve a 3D scanning pattern. One of the out-of-plane modes along with two orthogonal torsional modes can be employed for scanning a large depth-stack in sparse fashion while another out-of-plane mode can satisfy a much higher scan fill-rate with less field of view (FOV). Simulations of the micro-scanner are obtained using finite element method (FEM) software and compared with the characterization data gathered from Laser Doppler Vibrometer (LDV). Using various out-of-plane modes, the constructed fill patterns are simulated on MATLAB and fill rates compared. Full article
Open AccessProceedings On the Applicability of Silicon Carbide Based Field Effect Sensors in the Control of Exhaust/Flue Gas After-Treatment Systems
Proceedings 2018, 2(13), 1068; https://doi.org/10.3390/proceedings2131068
Published: 27 November 2018
Viewed by 97 | PDF Full-text (778 KB)
Abstract
The performance of Silicon Carbide based field effect gas sensor devices, modified to enable long-term reliable operation with improved sensitivity to e.g., NH3 and CO at relevant temperatures for exhaust/flue gas emissions monitoring and control of combustion processes as well as after-treatment
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The performance of Silicon Carbide based field effect gas sensor devices, modified to enable long-term reliable operation with improved sensitivity to e.g., NH3 and CO at relevant temperatures for exhaust/flue gas emissions monitoring and control of combustion processes as well as after-treatment systems in automotive/stationary applications has been investigated with promising results. Full article
Open AccessProceedings Hierarchically Combined Periodic SERS Active 3D Micro- and Nanostructures for High Sensitive Molecular Analysis
Proceedings 2018, 2(13), 1069; https://doi.org/10.3390/proceedings2131069 (registering DOI)
Published: 14 December 2018
PDF Full-text (1224 KB)
Abstract
To increase the local field intensity of Raman scattering, gold nanospheres were entrapped in gold coated periodic inverse pyramid structures, being SERS substrates by themselves. The applicability of this complex structure for sensitive molecule detection was proved by comparison of the detected Raman
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To increase the local field intensity of Raman scattering, gold nanospheres were entrapped in gold coated periodic inverse pyramid structures, being SERS substrates by themselves. The applicability of this complex structure for sensitive molecule detection was proved by comparison of the detected Raman signals with and without particle entrapment. Moreover its relevance in molecular diagnostic was also proposed considering the specific surface functionalisation of the gold nanoparticles. Full article
Open AccessProceedings Improved 3-Phase Current Transducer
Proceedings 2018, 2(13), 1070; https://doi.org/10.3390/proceedings2131070
Published: 26 November 2018
Viewed by 94 | PDF Full-text (532 KB)
Abstract
We propose improved contactless DC/AC current transducer for 3-phase current lines based on 8 integrated fluxgate sensors. Using proper processing we ideally achieve a complete suppression of external homogeneous fields, and field gradients up to the 4th order. The sensitivity to external currents
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We propose improved contactless DC/AC current transducer for 3-phase current lines based on 8 integrated fluxgate sensors. Using proper processing we ideally achieve a complete suppression of external homogeneous fields, and field gradients up to the 4th order. The sensitivity to external currents (crosstalk) is improved 15-times compared to [1]. The usage of micro fluxgate sensors instead of magnetoresistive sensors improves the temperature stability: the sensitivity temperature coefficient was reduced from 0.3%/K to 50 ppm/K and offset drift was reduced from 50 mA/K to 1 mA/K. Full article
Open AccessProceedings Exchangeable Miniaturized Mass Spectrometer Chip Based on Silicon Structures
Proceedings 2018, 2(13), 1071; https://doi.org/10.3390/proceedings2131071
Published: 30 November 2018
Viewed by 79 | PDF Full-text (614 KB)
Abstract
This paper reports a design of an exchangeable miniaturized mass spectrometry chip using spring-loaded pins and O-rings for electrical and fluidic connections. This planar microelectromechanical system (MEMS)-chip works with 300 µm high silicon structures between two borosilicate glasses and has a size of
[...] Read more.
This paper reports a design of an exchangeable miniaturized mass spectrometry chip using spring-loaded pins and O-rings for electrical and fluidic connections. This planar microelectromechanical system (MEMS)-chip works with 300 µm high silicon structures between two borosilicate glasses and has a size of 13 mm × 7 mm. Because of its small size a small vacuum pump is sufficient, and it is suitable for mobile measurements and portable applications. Because of exchangeability of MEMS-chips with fluidic and electrical high voltage connections a direct comparison between chips is possible. Full article
Open AccessProceedings Large Out-of-Plane Deflection MEMS Actuators for Optical Applications
Proceedings 2018, 2(13), 1072; https://doi.org/10.3390/proceedings2131072
Published: 30 November 2018
Viewed by 87 | PDF Full-text (1621 KB)
Abstract
The design and fabrication of an electrothermal MEMS actuation structure which is capable of producing large out-of-plane deflection is presented. The actuators are used to move a 1 mm2 mirror structure, where the large deflection allows one to achieve large beam steering
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The design and fabrication of an electrothermal MEMS actuation structure which is capable of producing large out-of-plane deflection is presented. The actuators are used to move a 1 mm2 mirror structure, where the large deflection allows one to achieve large beam steering angles. The electrothermal actuators are designed to operate via joule heating with a monolithically integrated heater. The proposed design was analyzed using finite element method simulation software (COMSOL 5.3a), to determine the thickness of each material layer, the initial out-of-plane upward deflections, the configuration of the heating element to achieve the desired actuation deformations, and the overall steady-state temperature distribution through the actuation structure due to Joule heating. Finally, the actuation assemblies were fabricated, released, tested and compared with our simulation results. Full article
Open AccessProceedings Redox Active Self-Assembled Monolayer Functioning as a pH Actuator
Proceedings 2018, 2(13), 1073; https://doi.org/10.3390/proceedings2131073
Published: 21 November 2018
Viewed by 134 | PDF Full-text (700 KB)
Abstract
Using electrochemical control to change the chemical environment in liquids is quite challenging because the small surface to volume ratio offered by traditional cells limits the release or modification of chemicals from the electrodes. Here we present the control of proton concentration (acidity)
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Using electrochemical control to change the chemical environment in liquids is quite challenging because the small surface to volume ratio offered by traditional cells limits the release or modification of chemicals from the electrodes. Here we present the control of proton concentration (acidity) using a combination of a redox active SAM, which allows ease of fabrication, control of the chemical reactions and repeatability, with a microfluidic design that provides large range and stability over time of the set acidity point, quasi-reversibility during several cycles, and capacity of miniaturization and scalability for multiplexing. Full article
Open AccessProceedings Preparation and Integration of a Multi-Wavelength LED Matrix for Testing Light Cell Interaction in a Novel Lens Less Optical Microscope
Proceedings 2018, 2(13), 1074; https://doi.org/10.3390/proceedings2131074
Published: 21 November 2018
Viewed by 128 | PDF Full-text (1048 KB)
Abstract
In this work we studied the influence of light emitting diode (LED) generated light on living cells which were cultivated in common cell culture microtiter plates. In detail we investigated signaling side effects including apoptosis by the use of a cell permeable peroxide
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In this work we studied the influence of light emitting diode (LED) generated light on living cells which were cultivated in common cell culture microtiter plates. In detail we investigated signaling side effects including apoptosis by the use of a cell permeable peroxide activatable fluorescent dye (5,6-Chloromethyl-2′,7′-dichlorodihydrofluorescein diacetate). A high level production of peroxides in UV and blue light exposed cells was measured while the light of longer wavelengths caused only minor effects on the cells. Full article
Open AccessProceedings MEMS Variable Area Capacitor for Room Temperature Electrometry
Proceedings 2018, 2(13), 1075; https://doi.org/10.3390/proceedings2131075
Published: 30 November 2018
Viewed by 84 | PDF Full-text (376 KB)
Abstract
This paper introduces a new way to detect charge using MEMS variable capacitors for extremely sensitive, room temperature electrometry. It is largely based on the electrometers introduced by Riehl et al. [1] except variable capacitance is created by a changing area, not a
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This paper introduces a new way to detect charge using MEMS variable capacitors for extremely sensitive, room temperature electrometry. It is largely based on the electrometers introduced by Riehl et al. [1] except variable capacitance is created by a changing area, not a changing gap. The new scheme will improve MEMS electrometers by eliminating the effects of squeeze-film damping and by theoretically increasing the maximum charge resolution by 70%. The charge conversion gain (the increase in output voltage per input unit charge) for this system is derived. The result show good agreement with MATLAB calculations. Full article
Open AccessProceedings Transfer Printing Technology for Fabricating Chemical Sensors Based on Tin Dioxide Nanowires
Proceedings 2018, 2(13), 1076; https://doi.org/10.3390/proceedings2131076
Published: 21 November 2018
Viewed by 171 | PDF Full-text (1055 KB)
Abstract
Multi-nanowire based chemical gas sensors were produced employing a fast and simple transfer printing technology. SnO2 nanowires (NWs) were grown by a specific two-step technology including spray pyrolysis deposition and a thermal annealing process in presence of a Cu-catalyst. Subsequently the SnO
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Multi-nanowire based chemical gas sensors were produced employing a fast and simple transfer printing technology. SnO2 nanowires (NWs) were grown by a specific two-step technology including spray pyrolysis deposition and a thermal annealing process in presence of a Cu-catalyst. Subsequently the SnO2 NWs were print transferred by a polydimethylsiloxane (PDMS) stamp on Si-substrates with gold inter-digital electrode structures (IDES) creating a multi-NW chemical sensing device. The print-transfer technology enables a fast, easy and cheap fabrication of NW-based sensor devices with a good reproducibility. High sensitivity to H2S has been achieved, the performance results are presented in this work. Full article
Open AccessProceedings A Diffusor/Nozzle Pump Based on a Magnetically Actuated Flexible PCB Diaphragm
Proceedings 2018, 2(13), 1077; https://doi.org/10.3390/proceedings2131077
Published: 16 November 2018
Viewed by 125 | PDF Full-text (665 KB)
Abstract
We present a valveless microfluidic pump utilizing an oscillating membrane made from a flexible printed circuit board. The microfluidic channel is fabricated by a 3D printing process and features diffuser/nozzle structures to obtain a directed flow; the flexible membrane is bonded to the
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We present a valveless microfluidic pump utilizing an oscillating membrane made from a flexible printed circuit board. The microfluidic channel is fabricated by a 3D printing process and features diffuser/nozzle structures to obtain a directed flow; the flexible membrane is bonded to the channel. The membrane is actuated via Lorentz forces to accomplish out-of-plane motions and push the fluid through the channel. A permanent magnet provides the static magnetic field required for the actuation. The simple fabrication method can potentially be used for inexpensive mass fabrication for disposable devices. Full article
Open AccessProceedings Influence of Buffer Thickness on Sensitivity of Pd-Coated Side Polished Single Mode Optical Fiber Hydrogen Sensor
Proceedings 2018, 2(13), 1078; https://doi.org/10.3390/proceedings2131078
Published: 26 November 2018
Viewed by 106 | PDF Full-text (354 KB)
Abstract
Optical fiber sensor which is based on palladium is highly sensitive to detect hydrogen. In this paper we analyzed the effect of buffer on sensitivity. Sensitivity is affected due to presence of buffer between side polished fiber core and hydrogen absorbing palladium layer.
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Optical fiber sensor which is based on palladium is highly sensitive to detect hydrogen. In this paper we analyzed the effect of buffer on sensitivity. Sensitivity is affected due to presence of buffer between side polished fiber core and hydrogen absorbing palladium layer. We optimized the buffer thicknesses for different palladium thickness to achieve maximum sensitivity. Full article
Open AccessProceedings Silicon-On-Nothing Micro-Pirani Gauge for Interior-Pressure Measurement
Proceedings 2018, 2(13), 1079; https://doi.org/10.3390/proceedings2131079
Published: 20 November 2018
Viewed by 111 | PDF Full-text (1995 KB)
Abstract
In the current work, we present a compact and cost effective Pirani gauge based on Silicon-On-Nothing (SON) technology. The proposed design uses an innovative approach of etching the sensing element directly in a crystalline silicon membrane. Such configuration allows pressure dependent heat losses
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In the current work, we present a compact and cost effective Pirani gauge based on Silicon-On-Nothing (SON) technology. The proposed design uses an innovative approach of etching the sensing element directly in a crystalline silicon membrane. Such configuration allows pressure dependent heat losses to act on the substrate not only through the bottom cavity and trenches but also via the top cavity on the lid, which is formed by means of a sacrificial layer. By ensuring process compatibility with other SON-based MEMS, the proposed device can be used as a tool for cavity pressure monitoring and product support over the whole life cycle of MEMS: ranging from fabrication to calibration during field tests. Performance of the device is investigated based on numerical simulations and measurements. Furthermore, work includes a discussion of the fabrication process along with an additional cavity pressure characterization. Full article
Open AccessProceedings Silicon-On-Nothing IR-Emitter for Gas Sensing Applications
Proceedings 2018, 2(13), 1080; https://doi.org/10.3390/proceedings2131080
Published: 20 November 2018
Viewed by 116 | PDF Full-text (1741 KB)
Abstract
Within the current work, we present a miniaturized IR-Emitter based on Silicon-On-Nothing (SON) technology capable of producing 10 ms pulses. Transition to monocrystalline silicon, as the material choice for the filament, is governed by improved reliability and greater thermal stability as opposed to
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Within the current work, we present a miniaturized IR-Emitter based on Silicon-On-Nothing (SON) technology capable of producing 10 ms pulses. Transition to monocrystalline silicon, as the material choice for the filament, is governed by improved reliability and greater thermal stability as opposed to polycrystalline silicon alternative, commonly used in such class of devices. Compact design, low-cost processing and exceptional filament material properties make the presented device a favorite solution for integrated gas sensing applications. Numerical modeling and measurements of the IR-Emitter are performed to investigate the heating dynamics and assess the structure’s behavior at extreme temperatures as well as confirm the target performance. Additionally, a part of the work is dedicated to cover the insight of used fabrication process and the discussion of further improvements. Full article
Open AccessProceedings Surface Functionalization of SU-8 Vertical Waveguide for Biomedical Sensing: Bacteria Diagnosis
Proceedings 2018, 2(13), 1081; https://doi.org/10.3390/proceedings2131081
Published: 16 November 2018
Viewed by 152 | PDF Full-text (450 KB)
Abstract
In this paper, we present an SU-8 based evanescent waveguide with a vertical structure as a biomedical sensor. The waveguide is designed vertically to generate evanescent waves on both left and right surfaces for sensing. It is fabricated by E-beam lithography with only
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In this paper, we present an SU-8 based evanescent waveguide with a vertical structure as a biomedical sensor. The waveguide is designed vertically to generate evanescent waves on both left and right surfaces for sensing. It is fabricated by E-beam lithography with only one-step process which has the advantage of a better surface quality compared with commonly used dry etching methods. Furthermore, fabrication time and cost is cut down greatly. The surface of the designed waveguide can be functionalized with antibodies to immobilize specific bacteria on it. After surface functionalization and incubation with E. coli solutions of different concentrations, the waveguides absorption was measured. The results demonstrate that the waveguide is sensitive to E. coli concentration changes. In addition, tapers were designed and added to the waveguide to relieve the alignment tolerance for the aim of making a plug-and-play bedside diagnostic system. Full article
Open AccessProceedings A Robust 3D- and Inkjet-Printed Capacitive Position Sensor for a Spectrometer Application
Proceedings 2018, 2(13), 1082; https://doi.org/10.3390/proceedings2131082
Published: 19 November 2018
Viewed by 135 | PDF Full-text (1183 KB)
Abstract
For the considered application of a Fourier Transform InfraRed (FTIR) spectrometer, a functional package and an inkjet-printed capacitive position sensor are built. The package is made of 3D-printed copper. The copper is then coated with insulator onto which inkjet-printed silver electrodes are subsequently
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For the considered application of a Fourier Transform InfraRed (FTIR) spectrometer, a functional package and an inkjet-printed capacitive position sensor are built. The package is made of 3D-printed copper. The copper is then coated with insulator onto which inkjet-printed silver electrodes are subsequently applied. The whole structure builds up a capacitive position sensor. The target application is to measure the position of an electrostatically actuated Micro Electro Mechanical System (MEMS) mirror with nanometer accuracy at high bandwidths and large position offset. The MEMS mirror is part of a Michelson interferometer setup and driven at resonance. The large oscillation amplitude and high required resolution at resonance of the MEMS mirror are also the reason for high demands on the position measurement. Robustness against disturbing frequencies is assured by employment of a carrier-frequency read-out structure. Full article
Open AccessProceedings Contactless Sleep Monitoring Measurement Setup
Proceedings 2018, 2(13), 1083; https://doi.org/10.3390/proceedings2131083
Published: 20 November 2018
Viewed by 128 | PDF Full-text (637 KB)
Abstract
In this work, a contactless measurement setup based on a low-cost weighing scale sensor is presented. The positioning of the sensor is a key point in our work with ballistocardiographic (BCG) measurements. This was demonstrated using a strain-gauge sensor placed at the head
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In this work, a contactless measurement setup based on a low-cost weighing scale sensor is presented. The positioning of the sensor is a key point in our work with ballistocardiographic (BCG) measurements. This was demonstrated using a strain-gauge sensor placed at the head of the mattress to record the BCG signals, while an unsupervised machine learning algorithm was implemented to detect respiratory and cardiac cycles from patients laying in different postures. Comparison of BCG with electrocardiography (ECG) has shown the ability to detect, at least, 75% of every single heartbeat with the suggested setup and algorithm irrespective of patient’s postures. Full article
Open AccessProceedings Nonlinear Analytical Model of Two Weakly Coupled MEMS Cantilevers for Mass Sensing Using Electrostatic Actuation
Proceedings 2018, 2(13), 1084; https://doi.org/10.3390/proceedings2131084
Published: 19 November 2018
Viewed by 151 | PDF Full-text (816 KB)
Abstract
This paper presents a nonlinear analytical model of MEMS mass sensor, which is composed of two cantilevers of 98 µm and 100 µm length, 20 µm width and 1.3 µm thick. They are connected by a coupling beam and only the shortest cantilever
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This paper presents a nonlinear analytical model of MEMS mass sensor, which is composed of two cantilevers of 98 µm and 100 µm length, 20 µm width and 1.3 µm thick. They are connected by a coupling beam and only the shortest cantilever is actuated by a combined AC-DC voltage. The DC voltage is used to equilibrate the system and the phenomenon of mode localization is investigated when a mass perturbation is applied. The sensor is modeled as a continuous system with beam theory and non-ideal boundary conditions are considered by using flexible supports. With a low AC voltage of 10 mV, a DC voltage of 5.85 V can counterbalance the length difference. This DC voltage decreases at 5.60 V when we increase the AC voltage, due to the effect of electrostatic nonlinearities. For a relative added mass of 0.1%, the amplitude change in the two cantilevers is more important when the coupling is weaker. Full article
Open AccessProceedings Solid State Gas Sensor Based on Polyaniline Doped with [3,3′-Co(1,2-C2B9H11)2]−1 for Detection of Acetone: Diagnostic to Heart Failure Disease
Proceedings 2018, 2(13), 1086; https://doi.org/10.3390/proceedings2131086
Published: 3 December 2018
Viewed by 86 | PDF Full-text (417 KB)
Abstract
Acetone in human breath has been regarded as the important disease marker of Heart failure (HF). Therefore, preliminary study has been carried out for the use chemical sensor based on Polyaniline doped with [3,3′-Co(1,2-C2B9H11)2]−1 anion (PANI/COSANE) for the detection and quantification of
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Acetone in human breath has been regarded as the important disease marker of Heart failure (HF). Therefore, preliminary study has been carried out for the use chemical sensor based on Polyaniline doped with [3,3′-Co(1,2-C2B9H11)2]−1 anion (PANI/COSANE) for the detection and quantification of acetone in human breath. This chemical sensor was prepared by Galvano-statically growing a polymeric layer based on PANI/COSANE and PANI/Nitrate by electrochemical polymerization onto the two different interdigitated gold microelectrodes on a silicon chip surface using cyclic voltammetry. Measurement of change in conductance due to the presence of acetone in its vicinity at room temperature (20–25 °C) is performed in differential configuration mode using Lock-in amplifier. The developed acetone sensor has been calibrated under different acetone atmospheres using a Lock-in amplifier. This novel Acetone micro sensor showed good response, recovery, and stability for the detection of acetone in the range of 1 ppm–8 ppm. Full article
Open AccessProceedings Integrated Microprisms Matrix for Coupling a Laser Beam in Microfluidic Systems
Proceedings 2018, 2(13), 1087; https://doi.org/10.3390/proceedings2131087
Published: 12 December 2018
PDF Full-text (396 KB)
Abstract
It is still a challenge to integrate the optoelectronic technology in microfluidic analytical systems, due to the complex alignment of the optical components within the microchip, or expensive and complicated methods of their fabrication. In this paper, inexpensive, glass microprisms matrix, with high
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It is still a challenge to integrate the optoelectronic technology in microfluidic analytical systems, due to the complex alignment of the optical components within the microchip, or expensive and complicated methods of their fabrication. In this paper, inexpensive, glass microprisms matrix, with high quality surface and precise 54.7° reflection angle is presented. Fabrication and integration of optical components into the substrate is done using conventional microfabrication techniques such as soft lithography and anode bonding. The results of beam intensity measurements propagating within the glass substrate are presented, showing the possibility of controlled coupling of the beam into the substrate using integrated glass optical structures for microfluidic systems. Full article
Open AccessProceedings Creep Compensation in an Electrostatic PDMS-Membrane Actuator with Flexible Silver Nanowire Electrodes
Proceedings 2018, 2(13), 1088; https://doi.org/10.3390/proceedings2131088
Published: 11 December 2018
PDF Full-text (597 KB)
Abstract
An electrostatic membrane actuator with an elastomer membrane as movable part and silver nanowires (AgNWs) as flexible electrode material is built and characterized. A layered and modular actuator design facilitates simple and fast modification of actuator properties for characterization purposes. The tested actuators
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An electrostatic membrane actuator with an elastomer membrane as movable part and silver nanowires (AgNWs) as flexible electrode material is built and characterized. A layered and modular actuator design facilitates simple and fast modification of actuator properties for characterization purposes. The tested actuators allow a membrane center deflection in the range of over 50 μm with applied voltages lower than 1 kV. The observable membrane center deflection exhibits a viscoelastic creep behavior. With the aim to achieve a more stable membrane deflection, a simple correction function was applied to the constant electrode voltage thus compensating the linear creep rate. With this method, the creep rate was changed from +0.27 μm/s to −0.08 μm/s. This method already improves the stability of the actuator deflection to a high degree. Full article
Open AccessProceedings Membrane Deflection and Stress in Thermal Flow Sensors