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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 226 | 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 180 | 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 227 | 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 179 | 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
Published: 13 December 2018
Viewed by 288 | 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
Published: 14 December 2018
Viewed by 409 | 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 226 | 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
Viewed by 208 | 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 187 | 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 Capacitive Tactile Sensor with Concentric-Shape Electrodes for Three-Axial Force Measurement
Proceedings 2018, 2(13), 708; https://doi.org/10.3390/proceedings2130708
Published: 19 December 2018
Viewed by 242 | PDF Full-text (745 KB)
Abstract
In this paper, a novel capacitive tactile sensing device has proposed and demonstrated to solve coupling problem within the normal force and shear force by the unique design of electrode shape. In addition, the tactile sensor was added in the measuring capability of [...] Read more.
In this paper, a novel capacitive tactile sensing device has proposed and demonstrated to solve coupling problem within the normal force and shear force by the unique design of electrode shape. In addition, the tactile sensor was added in the measuring capability of torsion sensing compared with traditional capacitive sensor. The perceptive unit of tactile sensor, which was consist of five sensing electrodes to detect three-axial force. The complete tactile sensor composed of a top electrode, a bottom electrode, and a spacer layer. Each capacitive sensing unit comprised a pair of the concentric-shape but different size electrodes (top electrode and bottom electrode). In the future, the proposed tactile sensor can be utilized in the wearable devices, flexible interface, and bionic robotic skins. 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 207 | 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 198 | 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 161 | 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 255 | 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 Low-Offset In-Plane Sensitive Hall Arrangement
Proceedings 2018, 2(13), 713; https://doi.org/10.3390/proceedings2130713
Published: 21 December 2018
Viewed by 215 | PDF Full-text (319 KB)
Abstract
A novel in-plane sensitive Hall arrangement consisting of two identical n-Si three-contact (3C) elements and realized in a common technological process, is presented. In the solution, the minimization of the offset and its temperature drift is achieved by cross-coupling of the outer [...] Read more.
A novel in-plane sensitive Hall arrangement consisting of two identical n-Si three-contact (3C) elements and realized in a common technological process, is presented. In the solution, the minimization of the offset and its temperature drift is achieved by cross-coupling of the outer device contacts. This terminals’ connection provides equalizing currents between the two substrates which strongly compensate the inevitable difference in the electrical conditions in the two parts of the arrangement. As a result, the residual offset of both integrated Hall elements at the output Vout(0) and its temperature drift are strongly minimized. The residual offset is about 160 times smaller than the single-configuration one. The obtained output voltage-to-residual offset ratio at sensitivity of SRI ≈ 98 V/AT is very promising, reaching 6 × 103 at temperature T = 40 °C and induction 1 T. As a result, increased metrological accuracy for numerous applications is achieved. For a first time through the novel arrangement a suppression of sensitivity in the presence of external magnetic field could be achieved in order to obtain permanent offset information. This is one of the key results in the Hall device investigation. Full article
Open AccessProceedings Water-Dielectric Single Electrode Mode Triboelectric Nanogenerators for Ocean Wave Impact Energy Harvesting
Proceedings 2018, 2(13), 714; https://doi.org/10.3390/proceedings2130714
Published: 21 December 2018
Viewed by 297 | PDF Full-text (805 KB)
Abstract
The effect of water wave impacts and breakdown on the output performance of Water-Dielectric Single Electrode Mode Triboelectric Nanogenerators (WDSE-TENG) has been evaluated. When water contacts a TENG consisting of a hydrophobic dielectric layer, the triboelectric effect is generated with a net negative [...] Read more.
The effect of water wave impacts and breakdown on the output performance of Water-Dielectric Single Electrode Mode Triboelectric Nanogenerators (WDSE-TENG) has been evaluated. When water contacts a TENG consisting of a hydrophobic dielectric layer, the triboelectric effect is generated with a net negative charge on the dielectric material and net positive charge on the water surface. The hydrophobic dielectric materials, which show the highest electrical output performance in contact with water, were FEP, silicone rubber and polyimide. The average output power of each sample for a load resistance of 10 MΩ was found to be in the range 14.69 to 19.12 µW. The results demonstrate that WDSE-TENG devices can work as an alternative energy harvesting mechanism by using water as a triboelectric material. 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
Viewed by 205 | 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 A Novel Low Cost Wireless Incontinence Sensor System (Screen-Printed Flexible Sensor System) for Wireless Urine Detection in Incontinence Materials
Proceedings 2018, 2(13), 716; https://doi.org/10.3390/proceedings2130716
Published: 21 December 2018
Viewed by 255 | PDF Full-text (1532 KB)
Abstract
In this paper we present a printed, fast, high-sensitive and cheap wireless incontinence sensor [...]
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 184 | 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 164 | 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 Inkjet 3D Printed Micropot with Integrated Cantilever-Like Force Sensor for Growing Plant Biological Potential Measurement
Proceedings 2018, 2(13), 720; https://doi.org/10.3390/proceedings2130720
Published: 8 January 2019
Viewed by 258 | PDF Full-text (2195 KB)
Abstract
In this paper we present a results of fabrication of 3D printed micropot with integrated cantilever-like force sensor. Different thickness cantilevers was used. Presented micropot was use for characterization of grow Lepidium sativium. 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 184 | 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 209 | 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 MOEMS Based Single Chip Lorentz Force Magnetic Gradiometer
Proceedings 2018, 2(13), 724; https://doi.org/10.3390/proceedings2130724
Published: 21 December 2018
Viewed by 285 | PDF Full-text (1636 KB)
Abstract
The functional principle of an optical gradient magnetic field sensor consisting of two independent laterally oscillating masses on a single chip is reported. These oscillations are caused by the Lorentz forces resulting from an alternating current through the masses interacting with a static [...] Read more.
The functional principle of an optical gradient magnetic field sensor consisting of two independent laterally oscillating masses on a single chip is reported. These oscillations are caused by the Lorentz forces resulting from an alternating current through the masses interacting with a static magnetic field. Light is modulated by relative in-plane movement of the masses and a fixed frame and subsequently detected by two photodiodes. Evaluation of magnitude and phase of the output signal reveals information about the uniformity of the magnetic field. The sensor is capable of detecting uniaxially strength and direction of magnetic gradient fields, offset gradient fields and homogeneous fields. 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), 725; https://doi.org/10.3390/proceedings2130725
Published: 10 December 2018
Viewed by 186 | 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 Dynamic Mechanical Simulation of Miniature Silicon Membrane during Air Blast for Pressure Measurement
Proceedings 2018, 2(13), 727; https://doi.org/10.3390/proceedings2130727
Published: 18 December 2018
Viewed by 282 | PDF Full-text (578 KB)
Abstract
The development of new ultra-fast sensors for pressure air blast monitoring requires taking into account the very short rise time of pressure occurring during explosion. Simulations show here that the dynamic mechanical behavior of membrane-based sensors depends significantly on this rise time when [...] Read more.
The development of new ultra-fast sensors for pressure air blast monitoring requires taking into account the very short rise time of pressure occurring during explosion. Simulations show here that the dynamic mechanical behavior of membrane-based sensors depends significantly on this rise time when the fundamental mechanical resonant frequency of the membrane is higher than 10 MHz. Full article
Open AccessProceedings Characterization of a Vertical-Cavity Enhanced Detector for Narrowband Detection in the Mid-Infrared
Proceedings 2018, 2(13), 728; https://doi.org/10.3390/proceedings2130728
Published: 25 February 2019
Viewed by 117 | PDF Full-text (469 KB)
Abstract
In this work we present the experimental characterization of a vertical-cavity enhanced resonant detector (VERD) optimized for detection in the mid-infrared. We demonstrate that the VERD shows a 7.1 times higher absorption and responsivity at 4.26 µm compared to a bare metal absorber. [...] Read more.
In this work we present the experimental characterization of a vertical-cavity enhanced resonant detector (VERD) optimized for detection in the mid-infrared. We demonstrate that the VERD shows a 7.1 times higher absorption and responsivity at 4.26 µm compared to a bare metal absorber. As such this design can be easily optimized and integrated to specifically enhance the absorption around the design wavelength. 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
Published: 13 December 2018
Viewed by 253 | 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
Viewed by 172 | 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 164 | 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
Viewed by 229 | 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 Electromechanical Modelling of a Piezoelectric Stack Energy Harvester
Proceedings 2018, 2(13), 733; https://doi.org/10.3390/proceedings2130733
Published: 18 December 2018
Viewed by 258 | PDF Full-text (315 KB)
Abstract
In this paper, the behavior of a piezoelectric stack generator subject to a direct mechanical force, such as that experienced by pedestrian loads, is characterized and modelled. A lumped element model is developed that describes the electrical output of piezoelectric stack generators for [...] Read more.
In this paper, the behavior of a piezoelectric stack generator subject to a direct mechanical force, such as that experienced by pedestrian loads, is characterized and modelled. A lumped element model is developed that describes the electrical output of piezoelectric stack generators for quasi-static, off-resonance and random input conditions which are typical of underfloor or supporting structure energy harvesters. This research demonstrates the ability for accurate predictions of output voltage and current based on the material properties and geometry of the piezoelectric stack. The behavior of real-world random loading patterns is incorporated in the model, pairing mechanical input with interfacing circuitry requirements in order to maximize energy transfer. The developed model facilitates time-efficient design by reducing the simulation time to the order of seconds. 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 223 | 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
Viewed by 245 | 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 Intellectual Thermoconductometric Unit Based on Aerosol Printed Ceramic MEMS Sensor for the Measurement of Natural Gas Composition
Proceedings 2018, 2(13), 736; https://doi.org/10.3390/proceedings2130736
Published: 24 December 2018
Viewed by 247 | PDF Full-text (713 KB)
Abstract
The online control of natural gas quality is important for customers, because for them the important value is calorific value of consumed gas, but not its volume. The application of thermoconductometric sensor gives simple possibility to fabricate imbedded intellectual plug-and-play device for this [...] Read more.
The online control of natural gas quality is important for customers, because for them the important value is calorific value of consumed gas, but not its volume. The application of thermoconductometric sensor gives simple possibility to fabricate imbedded intellectual plug-and-play device for this control. The ceramic MEMS sensor based on a combination of this ceramic LTCC membrane and aerosol jet printed platinum microheater was used as a sensing element of this unit. The electronic unit controlling the sensor was designed to stabilize the temperature of the microheater and to measure power necessary to maintain this temperature at different concentrations of N2and CO2 in natural gas. The application of this unit enables the measurement of admixtures of nitrogen and CO2 with detection limit of about 1 vol. % sufficient for the application in gas meter instruments. 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 145 | PDF Full-text (1914 KB)
Open AccessProceedings Platinum Based Material for Additive Technology of Gas Sensors
Proceedings 2018, 2(13), 738; https://doi.org/10.3390/proceedings2130738
Published: 20 December 2018
Viewed by 208 | PDF Full-text (873 KB)
Abstract
We prepared platinum nanoparticle ink usable for the fabrication of MEMS microheaters
of high-temperature gas sensors and thermoresistors operating up to 450 °C and present some
preliminary results on the application of the ink in sensor microheater manufacturing. The ink
consists of platinum [...] Read more.
We prepared platinum nanoparticle ink usable for the fabrication of MEMS microheaters
of high-temperature gas sensors and thermoresistors operating up to 450 °C and present some
preliminary results on the application of the ink in sensor microheater manufacturing. The ink
consists of platinum particles (3–8 nm) suspended in ethylene glycol solution of polyvinylpyrrolidone.
The ink is usable in both InkJet and AerosolJet printers. The annealing at temperature of about 600 °C
leads to the formation of uniform microheater structure. The experiments on microheater aging
confirm the stability of the printed microstructure at 450 °C for at least one year of operation. The
substrates used for printing were thin alumina and LTCC ceramics with thickness of 12–20 μm. Full article
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 193 | 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 197 | 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 231 | 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 186 | 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 197 | 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 216 | 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 [...] Read more.
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 203 | 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 178 | 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 [...] Read more.
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 210 | 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 328 | 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 200 | 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 Fabrication of a CMOS-based Imaging Chip with Monolithically Integrated RGB and NIR Filters
Proceedings 2018, 2(13), 751; https://doi.org/10.3390/proceedings2130751
Published: 8 January 2019
Viewed by 250 | PDF Full-text (631 KB)
Abstract
Recent developments in multispectral cameras have demonstrated how compact and low-cost spectral sensors can be made by monolithically integrating filters on top of commercially available image sensors. In this paper, the fabrication of a RGB + NIR variation to such a single-chip imaging [...] Read more.
Recent developments in multispectral cameras have demonstrated how compact and low-cost spectral sensors can be made by monolithically integrating filters on top of commercially available image sensors. In this paper, the fabrication of a RGB + NIR variation to such a single-chip imaging system is described, including the integration of a metallic shield to minimize crosstalk, and two interference filters: a NIR blocking filter, and a NIR bandpass filter. This is then combined with standard polymer based RGB colour filters. Fabrication of this chip is done in imec’s 200 mm cleanroom using standard CMOS technology, except for the addition of RGB colour filters and microlenses, which is outsourced. 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 211 | 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 190 | 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 189 | 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
Viewed by 159 | 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 162 | 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 159 | 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 195 | 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 217 | 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 186 | 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
Viewed by 190 | 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 170 | 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 188 | 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 208 | 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 MEMS Non-Absorbing Electromagnetic Power Sensor Employing the Effect of Radiation Pressure
Proceedings 2018, 2(13), 767; https://doi.org/10.3390/proceedings2130767
Published: 24 December 2018
Viewed by 268 | PDF Full-text (515 KB)
Abstract
We demonstrate a compact electromagnetic power sensor based on force effects of electromagnetic radiation onto a highly reflective mirror surface. Unlike the conventional power measurement approach, the photons are not absorbed and can be further used in the investigated system. In addition, the [...] Read more.
We demonstrate a compact electromagnetic power sensor based on force effects of electromagnetic radiation onto a highly reflective mirror surface. Unlike the conventional power measurement approach, the photons are not absorbed and can be further used in the investigated system. In addition, the exerted force is frequency-independent, yielding a wide measurement frequency span being practically limited by the wavelength-dependent mirror reflection coefficient. The mechanical arrangement of two sensing elements in tandem suppresses the influence of gravity and vibrations on the power reading. We achieve a noise floor of about 1 W/√Hz and speed of 100 ms, being practically limited by sensor’s dynamics and lock-in amplifier filter settling time. 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 195 | 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 Improvement Methods for Colorimetric Gas Sensor for Use in Indoor Livestock Farming
Proceedings 2018, 2(13), 769; https://doi.org/10.3390/proceedings2130769
Published: 25 February 2019
Viewed by 152 | PDF Full-text (709 KB)
Abstract
Different published colorimetric sensors were investigated with the ultimate goal to develop a colorimetric sensor for a closed livestock farm, applicable in a rough environment. The methods were investigated to improve the lack of sensitivity, roughness, and reproduction of colorimetric sensors. The methods [...] Read more.
Different published colorimetric sensors were investigated with the ultimate goal to develop a colorimetric sensor for a closed livestock farm, applicable in a rough environment. The methods were investigated to improve the lack of sensitivity, roughness, and reproduction of colorimetric sensors. The methods investigated varied from changing matrices, changing substrates, treatment of the substrates, and investigation of the distribution by camera of the chemical thin layer and investigation on temperature, water and cross interference of several other gases in the livestock gas matrix. Results showed that with changing several important parameters, other than only the choice of a color indicator results in a serious improvement of the sensor specification and an improved performance necessary for the rough circumstances in livestock farming. 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 215 | 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 137 | 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 Design and Fabrication of MOS Type Gas Sensor with Vertically Integrated Heater Using CMOS-MEMS Technology
Proceedings 2018, 2(13), 772; https://doi.org/10.3390/proceedings2130772
Published: 19 December 2018
Viewed by 256 | PDF Full-text (949 KB)
Abstract
This study implements the metal-oxide-semiconductor (MOS) type gas sensor using the TSMC 0.35 μm 2P4M process. The gas concentration is detected based on the resistance change measured by the proposed sensor. This design has three merits: (1) low-cost post-CMOS process using metal/oxide wet [...] Read more.
This study implements the metal-oxide-semiconductor (MOS) type gas sensor using the TSMC 0.35 μm 2P4M process. The gas concentration is detected based on the resistance change measured by the proposed sensor. This design has three merits: (1) low-cost post-CMOS process using metal/oxide wet etching, (2) composite sensing material based on ZnO-SnO2 coating on the CMOS-MEMS structure, (3) vertical integration of heater and ZnO-SnO2 gas-sensing films using CMOS-MEMS and drop casting technologies. Proposed design significantly increase the sensitivity at the high operating temperature. In summary, the sensitivity of presented sensor increased from 0.04%/% (O2/N2) at near room operating temperature to 0.2%/%(O2/N2) at near 140 °C for the range of 5–50% oxygen concentration. 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 194 | 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 174 | 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 187 | 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
Viewed by 192 | 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
Viewed by 172 | 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
Viewed by 160 | 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
Viewed by 245 | 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 [...] Read more.
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
Published: 13 December 2018
Viewed by 280 | 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 Influence of Sensor Network Sampling Rate on Multivariate Statistical Condition Monitoring of Industrial Machines and Processes
Proceedings 2018, 2(13), 781; https://doi.org/10.3390/proceedings2130781
Published: 26 December 2018
Viewed by 329 | PDF Full-text (710 KB)
Abstract
In this paper, the deterioration of statistical fault classification of a hydraulic system and an electromechanical cylinder EMC due to reduced sampling rates of sensor nets is shown. As a result, two types of faults can be distinguished: On the one hand, degradation [...] Read more.
In this paper, the deterioration of statistical fault classification of a hydraulic system and an electromechanical cylinder EMC due to reduced sampling rates of sensor nets is shown. As a result, two types of faults can be distinguished: On the one hand, degradation processes which primarily show static symptoms over the whole working cycle and, thus, are less susceptible to reduced time resolution; on the other hand, the detection of faults with symptoms localized in time, e.g., during transients, is significantly degraded. Furthermore, the EMC example shows the importance of data representation that needs to be adapted to the sampling rate. 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
Viewed by 221 | 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 227 | 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 234 | 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 Buckling Porous SiC Membranes
Proceedings 2018, 2(13), 785; https://doi.org/10.3390/proceedings2130785
Published: 17 December 2018
Viewed by 264 | PDF Full-text (460 KB)
Abstract
In preliminary studies it could be shown that single crystalline silicon carbide wafers can be porosified with metal assisted photochemical etching. Furthermore, the generation of porous areas which are locally defined is possible with this method. By adjusting the etching parameters, a highly [...] Read more.
In preliminary studies it could be shown that single crystalline silicon carbide wafers can be porosified with metal assisted photochemical etching. Furthermore, the generation of porous areas which are locally defined is possible with this method. By adjusting the etching parameters, a highly porous layer (degree of porosity of 90%) can be formed which is under-etched by a line of breakage. By depositing a compressively stressed amorphous SiC:H thin film on top of a porous region, the a-SiC:H film can be locally separated from the substrate, resulting in a buckled membrane configuration. Such membranes might open up potential applications in MEMS design concepts. 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 215 | 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
Cited by 1 | Viewed by 229 | 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 185 | 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 218 | 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 214 | 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 183 | 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 3D Printing of Highly Stretchable and Sensitive Strain Sensors Using Graphene Based Composites
Proceedings 2018, 2(13), 792; https://doi.org/10.3390/proceedings2130792
Published: 21 December 2018
Viewed by 303 | PDF Full-text (1125 KB)
Abstract
In this research, we present the development of 3D printed, highly stretchable and sensitive strain sensors using Graphene based composites. Graphene, a 2D material with unique electrical and piezoresistive properties, has already been used to create highly sensitive strain sensors. In this new [...] Read more.
In this research, we present the development of 3D printed, highly stretchable and sensitive strain sensors using Graphene based composites. Graphene, a 2D material with unique electrical and piezoresistive properties, has already been used to create highly sensitive strain sensors. In this new study, by co-printing Graphene based Polylactic acid (PLA) with thermoplastic polyurethane (TPU), a highly stretchable and sensitive strain sensor based on Graphene composites can be 3D printed for the first time in strain sensors. The fabrication process of all materials is fully compatible with fused deposition modeling (FDM) based 3D printing method, which makes it possible to rapidly prototype and manufacture highly stretchable and sensitive strain sensors. The mechanical properties, electrical properties, sensitivity of the 3D printed sensors will be presented. 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 223 | 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 228 | 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 206 | 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
Viewed by 167 | 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 742 | 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 207 | 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 179 | 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 201 | 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 154 | 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 165 | 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 235 | 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 Charging-Based PN Sensing of Automotive Exhaust Particles
Proceedings 2018, 2(13), 805; https://doi.org/10.3390/proceedings2130805
Published: 3 January 2019
Viewed by 289 | PDF Full-text (496 KB)
Abstract
Mobile measurement of particle number concentration (PN) in the exhaust of motor vehicles has recently become an integral part of emission legislation. Charge-based sensing techniques for the examination of PN, like Diffusion Charging (DC), represent a promising alternative to condensational particle counters (CPCs) [...] Read more.
Mobile measurement of particle number concentration (PN) in the exhaust of motor vehicles has recently become an integral part of emission legislation. Charge-based sensing techniques for the examination of PN, like Diffusion Charging (DC), represent a promising alternative to condensational particle counters (CPCs) as established PN sensors, because they enable to build robust, compact and energy efficient systems. However, due to the charging process, particle properties like size and morphology have a big impact on the sensor’s PN response. For particles of different size and shape we experimentally investigated those impacts using own-built charging-based sensors. The PN response of the DC sensor showed desired behavior for compact NaCl particles, but less satisfying behavior for combustion aerosol standard (CAST) particles, which is a widely used test aerosol for automotive applications. With a photoelectric charger, the PN response of CAST particles was significantly better. 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 211 | 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 180 | 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 202 | 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
Published: 13 December 2018
Viewed by 242 | 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 [...] Read more.
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
Viewed by 204 | PDF Full-text (811 KB)
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 [...] Read more.
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
Viewed by 160 | PDF Full-text (683 KB)
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 [...] Read more.
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 Enhancement of Gas Sensing Response on WO3 Thin Films Processed by Direct Laser Interference Patterning
Proceedings 2018, 2(13), 813; https://doi.org/10.3390/proceedings2130813
Published: 8 January 2019
Viewed by 220 | PDF Full-text (810 KB)
Abstract
Direct Laser Interference Patterning (DLIP) technique has been used to generate a line pattern on the surface of WO3 thin films, due to the interference of two coherent laser beams, modifying its surface morphology and physical properties. Gas sensing devices based on [...] Read more.
Direct Laser Interference Patterning (DLIP) technique has been used to generate a line pattern on the surface of WO3 thin films, due to the interference of two coherent laser beams, modifying its surface morphology and physical properties. Gas sensing devices based on WO3 thin films annealed at 600 °C and nanostructured by DLIP have been fabricated and compared to samples simply annealed at the same temperature. The sensors processed by DLIP present a great enhancement on the response in NO2 atmospheres indicating possible modifications on the composition, aside from the morphological one. 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 212 | 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 [...] Read more.
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
Viewed by 234 | 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 [...] Read more.
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 200 | 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 [...] Read more.
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 168 | 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 [...] Read more.
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
Published: 13 December 2018
Viewed by 253 | 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 [...] Read more.
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 190 | 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 [...] Read more.
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 Cross-Linked Nanoparticle Membranes for Microelectromechanical Chemical Sensors and Pressure Sensors
Proceedings 2018, 2(13), 821; https://doi.org/10.3390/proceedings2130821
Published: 22 January 2019
Viewed by 228 | PDF Full-text (571 KB)
Abstract
We present novel microelectromechanical chemical sensors for the detection of volatile organic compounds based on electrostatically actuated, nanometer-thin, freestanding membranes of organically cross-linked gold nanoparticles. The sensors employ quasi-static deflection amplitudes or resonance frequency shifts of the membranes as highly sensitive sensing signals [...] Read more.
We present novel microelectromechanical chemical sensors for the detection of volatile organic compounds based on electrostatically actuated, nanometer-thin, freestanding membranes of organically cross-linked gold nanoparticles. The sensors employ quasi-static deflection amplitudes or resonance frequency shifts of the membranes as highly sensitive sensing signals and are capable of detecting analytes at concentrations down to the low ppm range. We show that the devices can further be utilized for analyte discrimination. Additionally, we demonstrate that freestanding GNP membranes can be used for the fabrication of highly sensitive resistive pressure sensors. 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
Viewed by 226 | 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 [...] Read more.
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 215 | 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 [...] Read more.
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 Microscale Xylem Sap Flow Sensor Facilitating the Simultaneous Measurement of Flow Velocity and Direction
Proceedings 2018, 2(13), 824; https://doi.org/10.3390/proceedings2130824
Published: 31 January 2019
Viewed by 310 | PDF Full-text (1854 KB)
Abstract
In this study, we focused on direct and quantitative monitoring of sap dynamics in plant stems, and proposed the microscale xylem sap flow sensor. This sensor facilitates the simultaneous measurement of flow velocity and direction by combining the principles of a Granier sensor [...] Read more.
In this study, we focused on direct and quantitative monitoring of sap dynamics in plant stems, and proposed the microscale xylem sap flow sensor. This sensor facilitates the simultaneous measurement of flow velocity and direction by combining the principles of a Granier sensor and a thermal flow sensor. We fabricated micro-sensor chips for functional verification by using MEMS technology, and assembled them on a resin film to facilitate mounting on the epidermis of plants. Furthermore, we measured the sap dynamics by using an experimental setup, and succeeded in measuring the flow velocity and direction at the same time. 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
Viewed by 171 | 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 [...] Read more.
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 WO3 Based Gas Sensors
Proceedings 2018, 2(13), 826; https://doi.org/10.3390/proceedings2130826
Published: 9 January 2019
Viewed by 299 | PDF Full-text (1290 KB)
Abstract
WO3 is a commonly used material for gas sensing. Although a great deal of research has been done on how to tune sensors based on WO3, no clear consensus exists on what characteristics are inherent to the metal oxide: This [...] Read more.
WO3 is a commonly used material for gas sensing. Although a great deal of research has been done on how to tune sensors based on WO3, no clear consensus exists on what characteristics are inherent to the metal oxide: This work looks at six different WO3 samples and aims to identify which characteristics are common to all materials. Specifically, the interaction of the samples with humidity is examined. Full article
Open AccessProceedings Thermal Flow Sensor for Non‐Invasive Measurements in HVAC Systems
Proceedings 2018, 2(13), 827; https://doi.org/10.3390/proceedings2130827
Published: 24 December 2018
Viewed by 288 | PDF Full-text (652 KB)
Abstract
We present a feasibility study on non‐invasive flow rate measurements in heating, ventilation, and air conditioning (HVAC) systems utilizing thermal transduction instead of commonly used ultrasonic techniques. The investigated thermal flow transduction comprises two temperature sensors and a heater, all mounted non‐invasively on [...] Read more.
We present a feasibility study on non‐invasive flow rate measurements in heating, ventilation, and air conditioning (HVAC) systems utilizing thermal transduction instead of commonly used ultrasonic techniques. The investigated thermal flow transduction comprises two temperature sensors and a heater, all mounted non‐invasively on the outer pipe surface and, therefore, not disturbing the fluid flow inside. One temperature sensor measures the heater temperature, whereas the other one, mounted upstream of the heater, follows the fluid temperature for reference. The temperature difference (i.e., the heater excess temperature) depends on the fluid velocity and can be used to derive the mean volume flow inside the pipe. In order to visualize and study the temperature field, a finite element method (FEM) model of the system was implemented. Measurements conducted with the sensor prototype confirm the feasibility of this approach. 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
Viewed by 248 | 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, [...] Read more.
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
Viewed by 173 | 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 [...] Read more.
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
Viewed by 197 | 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 [...] Read more.
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
Viewed by 181 | 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 [...] Read more.
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 Hypersensitive Electrochemical Sequential Monitoring of Total IgE and their Effects with Ovalbumin Induced Mice
Proceedings 2018, 2(13), 832; https://doi.org/10.3390/proceedings2130832
Published: 19 February 2019
Viewed by 149 | PDF Full-text (847 KB)
Abstract
Monitoring of specific biomarker is critical for determining progression of a disease or efficacy of a treatment. Currently, the standard for assessing amount of specific biomarkers is the enzyme linked immunosorbent assay (ELISA), which measures quantities on the nanogram scale. However, ELISA has [...] Read more.
Monitoring of specific biomarker is critical for determining progression of a disease or efficacy of a treatment. Currently, the standard for assessing amount of specific biomarkers is the enzyme linked immunosorbent assay (ELISA), which measures quantities on the nanogram scale. However, ELISA has high material costs, long incubation periods, requires large volume of samples and involves special instruments, which necessitates clinical samples to be sent to a lab. In order to provide rapid, accurate, easy, point-of-care measurement of biomarkers, electrochemical immunosensor can be used to provide specific and sensitive biomarker detection. Immunosensor allow near real-time results, reduced costs, and simple assays with no labelling. In this work, we developed an electrochemical biosensor to measure total immunoglobulin E (IgE), a marker of asthma disease that varies with age, gender, and disease in concentrations from 0.3–1000 ng/mL with consuming 20 µL volume of real blood sample. Also, sequential monitoring of total IgE with OVA induced mice is another application of this work and this sensor is an alternative approach for recording data and a more effective assay for understanding the cytotoxic effects of toxic materials. 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
Cited by 1 | Viewed by 229 | 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 [...] Read more.
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 230 | 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 [...] Read more.
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 Vibration Mode Investigation of Piezoelectric Ultrasonic Microsensors on Buckled Diaphragms
Proceedings 2018, 2(13), 835; https://doi.org/10.3390/proceedings2130835
Published: 19 December 2018
Viewed by 207 | PDF Full-text (1580 KB)
Abstract
Vibration mode of piezoelectric ultrasonic microsensors was investigated on buckled diaphragm structures from the viewpoint of higher order vibration modes than the fundamental one. Several vibration modes were generated on the diaphragms as the response to an ultrasound pulse, and their natural frequencies [...] Read more.
Vibration mode of piezoelectric ultrasonic microsensors was investigated on buckled diaphragm structures from the viewpoint of higher order vibration modes than the fundamental one. Several vibration modes were generated on the diaphragms as the response to an ultrasound pulse, and their natural frequencies changed with increasing the buckling deflection in different rates. The natural frequencies of some modes approached each other, and the modes were accordingly superposed and degraded into a single mode in the large buckling ranges. The large buckling of the diaphragms consequently improves their vibration and thus the output waveforms. 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 170 | 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, [...] Read more.
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 186 | 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 [...] Read more.
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 Silicon Microcantilevers with ZnO Nanorods/Chitosan-SAMs Hybrids on Its Back Surface for Humidity Sensing
Proceedings 2018, 2(13), 838; https://doi.org/10.3390/proceedings2130838
Published: 21 December 2018
Viewed by 259 | PDF Full-text (1114 KB)
Abstract
This paper reports a piezoresistive silicon microcantilever-based gravimetric humidity sensor, where a ZnO nanofilm (200 nm) and ZnO nanorods (NRs) with different lengths (1.5 µm and 6 µm) modified with chitosan self-assembled monolayers (SAMs) are coated on the microcantilevers’ back surface as the [...] Read more.
This paper reports a piezoresistive silicon microcantilever-based gravimetric humidity sensor, where a ZnO nanofilm (200 nm) and ZnO nanorods (NRs) with different lengths (1.5 µm and 6 µm) modified with chitosan self-assembled monolayers (SAMs) are coated on the microcantilevers’ back surface as the sensing material. Thanks to the new sensor design, the resonant frequency (RF) shifts induced by the mass adsorption on the high surface-area-to-volume ratio, hybrid-sensing nanostructure can be tracked directly by monitoring the output of the p-diffused full Wheatstone bridge. By depositing ZnO NRs and Chitosan SAMs, direct-reading microcantilevers with high repeatability, reliability and high sensitivity (15 Hz/%RH) can be achieved. Full article
Open AccessProceedings Development of a Heat-Driven-Type MEMS Olfactory Display
Proceedings 2018, 2(13), 839; https://doi.org/10.3390/proceedings2130839
Published: 26 December 2018
Viewed by 280 | PDF Full-text (731 KB)
Abstract
An olfactory display is necessary for effective multimodal information communication. The relatively large size of current olfactory displays does not support integration with other information devices. Thus, in this study, a heat-driven-type microelectromechanical system (MEMS) olfactory display that is only a few square [...] Read more.
An olfactory display is necessary for effective multimodal information communication. The relatively large size of current olfactory displays does not support integration with other information devices. Thus, in this study, a heat-driven-type microelectromechanical system (MEMS) olfactory display that is only a few square centimeters in size and, thus, suitable for integration, is proposed. The olfactory display was fabricated by implementing a microfabrication process, and the fundamental driving conditions for the heater and valve were confirmed. Furthermore, a perfume diffusion experiment was conducted to characterize the olfactory display. The diffusion of the perfume was successfully synchronized with the open/close time of the valve. 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 220 | 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 [...] Read more.
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 186 | 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 [...] Read more.
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 191 | 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 [...] Read more.
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 162 | 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 [...] Read more.
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 168 | 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 [...] Read more.
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 231 | 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, [...] Read more.
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 170 | 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 [...] Read more.
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
Viewed by 246 | 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 [...] Read more.
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 245 | 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 238 | 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 179 | 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 Miniaturized Coplanar Waveguide for Nanostructured Magnetostrictive Multilayer Characterization
Proceedings 2018, 2(13), 851; https://doi.org/10.3390/proceedings2130851
Published: 17 January 2019
Viewed by 219 | PDF Full-text (733 KB)
Abstract
A miniaturized coplanar waveguide (CPW) on a Y-cut LiNbO3 substrate operating in Radio Frequency region (RF) is proposed for studying of magnetostrictive multi-layered structure. The structure is composed of a 14 × [TbCo2 (3.7 nm)/FeCo (4 nm)] nanostructured multi-layer. Using microtechnology process, [...] Read more.
A miniaturized coplanar waveguide (CPW) on a Y-cut LiNbO3 substrate operating in Radio Frequency region (RF) is proposed for studying of magnetostrictive multi-layered structure. The structure is composed of a 14 × [TbCo2 (3.7 nm)/FeCo (4 nm)] nanostructured multi-layer. Using microtechnology process, the miniaturized CPW has been designed with a 50 µm wide signal line in the frequency range from 6 MHz to 6 GHz. Electromagnetic simulations based on ®Ansys/HFSS demonstrate insertion losses less than 2 dB and show that the magnetic field is more confined in the nanostructured multi-layer placed on top of the micro-sized CPW. By using Vectorial Network Analyzer (VNA) the Ferromagnetic Resonance (FMR) is investigated from the reflection (Sii) or transmission (Sij) coefficients of scattering parameters. An inversion model is finally used to extract the complex permeability spectrum of the thin-film in a large frequency range. 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 260 | 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 224 | 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
Cited by 1 | Viewed by 233 | 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 204 | 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 225 | 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 253 | 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
Cited by 1 | Viewed by 205 | 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 244 | 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 201 | 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 308 | 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 205 | 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 160 | 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 232 | 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 217 | 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 318 | 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 192 | 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
Cited by 1 | Viewed by 245 | 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 213 | 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 219 | 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 Sensing Characteristics of Smart Microsensor Systems for Measuring Relative Humidity in Pressurized Air
Proceedings 2018, 2(13), 871; https://doi.org/10.3390/proceedings2130871
Published: 19 December 2018
Viewed by 252 | PDF Full-text (472 KB)
Abstract
The detailed experimental investigation of the performance of a commercially available smart humidity sensor used for the measurement of relative humidity at elevated pressures (0.1–2 MPa) is reported. A dedicated set-up was developed for generating defined humidities in pressurized air. The measurements reveal [...] Read more.
The detailed experimental investigation of the performance of a commercially available smart humidity sensor used for the measurement of relative humidity at elevated pressures (0.1–2 MPa) is reported. A dedicated set-up was developed for generating defined humidities in pressurized air. The measurements reveal that the pressure coefficient of the sensor deviation at a given relative humidity condition cannot be attributed solely to the enhancement factor of the humid air. For such microsensors, an additional sensor-specific pressure compensation factor was determined which is significant for precise measurements in applications with pressurized air. 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 202 | 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 202 | 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 203 | 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 182 | 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 196 | 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
Cited by 1 | Viewed by 258 | 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 235 | 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 [...] Read more.
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 241 | 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 223 | 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
Viewed by 201 | 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 Inkjet-Printing Polymer Nanocomposite for Detecting VOCs
Proceedings 2018, 2(13), 882; https://doi.org/10.3390/proceedings2130882
Published: 21 December 2018
Viewed by 334 | PDF Full-text (969 KB)
Abstract
Polymer nanocomposite (PNC) inks containing polyvinylpyrrolidone with a molecular weight of 40 kDa (PVP40) and a high structure carbon black (CB) were formulated for gas sensing applications. The formulation was optimized for inkjet printing by using a co-solvent system and tuning the ink’s [...] Read more.
Polymer nanocomposite (PNC) inks containing polyvinylpyrrolidone with a molecular weight of 40 kDa (PVP40) and a high structure carbon black (CB) were formulated for gas sensing applications. The formulation was optimized for inkjet printing by using a co-solvent system and tuning the ink’s viscosity. The Ink loaded with 10 wt.% PVP40, dissolved in a solvent mixture containing 70 wt.% deionized water and 30 wt.% gamma-butyrolactone showed an excellent printability. Adding up to 13 wt.% CB particles to the ink, with respect to polymer content, did not affect its printability. Printing PNC onto the sensor platform and measuring its response towards ethanol, acetone and humidity showed the higher affinity of the PNC to humidity and ethanol. 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 218 | 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 193 | 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 210 | 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 189 | 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
Cited by 2 | Viewed by 206 | 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 UV-LED Photo-Activated Room Temperature NO2 Sensors Based on Nanostructured ZnO/AlN Thin Films
Proceedings 2018, 2(13), 888; https://doi.org/10.3390/proceedings2130888
Published: 11 February 2019
Viewed by 195 | PDF Full-text (1117 KB)
Abstract
UV-light emitting diodes (395–278 nm) were used to investigate the gas sensing attributes of planar and nanostructured ZnO/AlN thin films on Si substrate towards NO2 at room temperature. A significant increased sensitivity ((Rg − Ra)/Ra = 65.3 [...] Read more.
UV-light emitting diodes (395–278 nm) were used to investigate the gas sensing attributes of planar and nanostructured ZnO/AlN thin films on Si substrate towards NO2 at room temperature. A significant increased sensitivity ((Rg − Ra)/Ra = 65.3 ppm NO2 in air) and a strong reduction in recovery time (Trec = 14 min) were already observed for the planar ZnO/AlN thin films under UV-B (305 nm) irradiation compared to the other UV wavelengths, while the device showed no obvious response in dark. By enlarging the surface-to-volume ratio of the sensors (i.e., creating nanostructured ZnO/AlN thin films), an increased response time is expected to be observed. 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 237 | 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 237 | 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 269 | 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 278 | 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 192 | 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 222 | 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 208 | 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
Cited by 1 | Viewed by 208 | 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 213 | 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 210 | 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 166 | 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 Desorption and Electrical Conductivity Studies of Indium Tin Oxide Powders and Thick Films
Proceedings 2018, 2(13), 901; https://doi.org/10.3390/proceedings2130901
Published: 21 December 2018
Viewed by 243 | PDF Full-text (623 KB)
Abstract
The influence of various gas compositions on surface adsorbate species and electrical conductivity of indium tin oxide (ITO) powders and thick films was studied. By combining results of temperature dependent desorption (TPD) with electrical conductivity measurements it was shown that, after exposure to [...] Read more.
The influence of various gas compositions on surface adsorbate species and electrical conductivity of indium tin oxide (ITO) powders and thick films was studied. By combining results of temperature dependent desorption (TPD) with electrical conductivity measurements it was shown that, after exposure to ambient air, the surfaces of both powders and films are covered with significant amounts of oxygen, water and carbon related species. While the influence of oxygen adsorbates has already been described for temperatures below 500 °C, desorption of some of these species could be detected at temperatures as high as 675 °C, with a significant influence on electrical film conductivity. 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 205 | 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
Viewed by 198 | 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 212 | 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 190 | 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 237 | 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
Cited by 1 | Viewed by 189 | 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 168 | 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 [...] Read more.
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 219 | 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. [...] Read more.
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 438 | 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 [...] Read more.
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 A Novel Bi-Stable MEMS Membrane Concept Based on a Piezoelectric Thin Film Actuator for Integrated Switching
Proceedings 2018, 2(13), 912; https://doi.org/10.3390/proceedings2130912
Published: 16 January 2019
Viewed by 230 | PDF Full-text (575 KB)
Abstract
This study reports on a novel bi-stable actuator with an integrated aluminum nitride (AlN) piezoelectric layer sandwiched between two electrodes. To achieve bistability, the membranes must exceed a characteristic compressive stress value, also called the critical stress. For this purpose, we used highly [...] Read more.
This study reports on a novel bi-stable actuator with an integrated aluminum nitride (AlN) piezoelectric layer sandwiched between two electrodes. To achieve bistability, the membranes must exceed a characteristic compressive stress value, also called the critical stress. For this purpose, we used highly c-axis orientated stress-controlled AlN with a thickness of 400 nm. First experiments showed, that it is possible to switch between the two stable ground states with at least two rectangular pulses at a frequency of 80 kHz and with a voltage Vpp of 40 V, resulting in a displacement of about 10 µm for each switching direction. 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 275 | 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 [...] Read more.
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 233 | 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 [...] Read more.
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 181 | 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 [...] Read more.
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 238 | 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 [...] Read more.
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 241 | 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 [...] Read more.
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 Novel Sensor Modules for Efficient Manufacturing of Natural Fiber Reinforced Plastics
Proceedings 2018, 2(13), 918; https://doi.org/10.3390/proceedings2130918
Published: 24 December 2018
Viewed by 272 | PDF Full-text (1037 KB)
Abstract
The investigation of wear resistant thin film sensor systems for the detection of temperature and melt distributions on the surface of an injection mold for the optimization of natural fibre reinforced plastic production is the theme of this paper. 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
Viewed by 220 | 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 232 | 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 [...] Read more.
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 174 | 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 [...] Read more.
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 Crown-Porphyrin Ligand for Optical Sensors Development
Proceedings 2018, 2(13), 922; https://doi.org/10.3390/proceedings2130922
Published: 21 December 2018
Viewed by 232 | PDF Full-text (747 KB)
Abstract
A novel porphyrin ligand, Zn(II)TPP-BPI-crown (ZnPC), functionalized with two dibenzo-crown-ether moieties was synthesized and tested as cation-sensitive ionophore. Fluorescence studies on ligand sensitivity towards a number of different metal cations (Na+, K+, Li+, Ca2+, Mg [...] Read more.
A novel porphyrin ligand, Zn(II)TPP-BPI-crown (ZnPC), functionalized with two dibenzo-crown-ether moieties was synthesized and tested as cation-sensitive ionophore. Fluorescence studies on ligand sensitivity towards a number of different metal cations (Na+, K+, Li+, Ca2+, Mg2+, Co2+, Cd2+, Pb2+, Cu2+, Zn2+ and NH4+) were carried out first in solution and then inside polymeric membrane optodes. Emission light signal was sufficiently brilliant to be captured by a low-cost computer webcam, while a commercial blue-light LED served as monochromic excitation light source. The influence on the ZnPC optode response of the lipophilic sites functionalization was investigated. The visibly (naked eye) observed color change of sensing material from green to red demonstrated the suitability of the ZnPC-based optodes to perform fast monitoring of Cu(II) ions in the concentration range between 6.6 × 10−7 and 2.4 × 10−2 mol/L with a low detection limit (estimated by s/n = 3 method) of 0.3 mg/L, which is lower than WHO guideline value of 2 mg/L. 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 178 | 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. [...] Read more.
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 225 | 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 [...] Read more.
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 200 | 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 [...] Read more.
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 201 | 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 [...] Read more.
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 216 | 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 [...] Read more.
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 210 | 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 [...] Read more.
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 219 | 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 [...] Read more.
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 269 | 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 [...] Read more.
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 177 | 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 [...] Read more.
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 188 | 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 207 | 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 [...] Read more.
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 220 | 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, [...] Read more.
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
Viewed by 263 | 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 [...] Read more.
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 Reduced Order Component & System Level Modelling for Fluid-Solid Interactions in Complex MEMS Devices
Proceedings 2018, 2(13), 937; https://doi.org/10.3390/proceedings2130937
Published: 11 January 2019
Viewed by 246 | PDF Full-text (612 KB)
Abstract
The time-efficient and accurate implementation of physics-based fluidic damping effects is still one of the biggest challenges in the simulation of complex MEMS devices. Two modelling approaches utilizing the CRAIG/BAMPTON component mode synthesis method are discussed and compared in context of a highly [...] Read more.
The time-efficient and accurate implementation of physics-based fluidic damping effects is still one of the biggest challenges in the simulation of complex MEMS devices. Two modelling approaches utilizing the CRAIG/BAMPTON component mode synthesis method are discussed and compared in context of a highly automated model generation procedure. The first approach uses a modal projection technique with pressure profiles obtained from REYNOLDS flow simulations using the thermal-fluidic analogy. The second approach is based on the representation of the fluidic domain in form of a generalized KIRCHHOFFian lumped flow resistance network model. Both methods are generally suited for the simulation of structures like gyroscopes or accelerometers, but show different behaviors in terms of scaling and complexity during the model generation step and in the final ROM. The methods are demonstrated on examples and are compared to optical measurements of an out-of-plane teeter-totter type accelerometer. Full article
Open AccessProceedings A 3-Degree-of-Freedom MEMS Mirror with Controllable Static and Dynamic Motion for Beam Steering
Proceedings 2018, 2(13), 938; https://doi.org/10.3390/proceedings2130938
Published: 17 December 2018
Viewed by 224 | PDF Full-text (531 KB)
Abstract
A 3 Degree-of-Freedom (DOF) MEMS mirror is presented which can direct the light beam on an objective point and also operate in a continuous resonance 2 DOF mode. The micro-mirror is actuated by Lorentz force and has 4 actuators embedded in 4 sides [...] Read more.
A 3 Degree-of-Freedom (DOF) MEMS mirror is presented which can direct the light beam on an objective point and also operate in a continuous resonance 2 DOF mode. The micro-mirror is actuated by Lorentz force and has 4 actuators embedded in 4 sides of a square mirror. By enabling the actuators, different types of tilting and linear motion can be achieved. The micro-mirror is able to work in either static mode by applying dc current or dynamic mode by applying an ac current at the mirror resonance frequency. The mirror showed a maximum tilt angle of 14.5° and 20° for an input rms power of 2 mW in the resonance mode. A linear motion of 200 µm was achieved by 65 mW of dc power. Full article
Open AccessProceedings Miniaturized Plasma Actuator Flow Measurements by MEMS-Based Thermal Conductivity Sensors
Proceedings 2018, 2(13), 939; https://doi.org/10.3390/proceedings2130939
Published: 19 December 2018
Viewed by 209 | PDF Full-text (1183 KB)
Abstract
The gasflow created by a minaturized dielectric barrier discharge (DBD) plasma actuator is measured by a MEMS-based thermal conductivity gas sensor giving an indication of flow velocity and flow direction. The possiblity of several sensors in a small area gives a far better [...] Read more.
The gasflow created by a minaturized dielectric barrier discharge (DBD) plasma actuator is measured by a MEMS-based thermal conductivity gas sensor giving an indication of flow velocity and flow direction. The possiblity of several sensors in a small area gives a far better accuracy of local flow phenomena compared to conventional sensors. This is important for a better understanding of plasma- induced flow characteristics. 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
Viewed by 196 | 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 [...] Read more.
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
Viewed by 268 | 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 [...] Read more.
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
Cited by 1 | Viewed by 226 | 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. [...] Read more.
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
Viewed by 195 | 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 [...] Read more.
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
Viewed by 232 | 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 [...] Read more.
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
Viewed by 283 | 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 [...] Read more.
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
Viewed by 207 | 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 [...] Read more.
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
Viewed by 187 | 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 [...] Read more.
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 180 | 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 236 | 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 [...] Read more.
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 208 | 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 Tungsten Oxide Based Sensor for Oxygen Detection
Proceedings 2018, 2(13), 952; https://doi.org/10.3390/proceedings2130952
Published: 26 December 2018
Viewed by 269 | PDF Full-text (263 KB)
Abstract
In this paper we report on the development tungsten oxide based chemiresistive sensors for the monitoring of oxygen at low temperatures (T ≤ 400 °C) in dry and humid air. The sensors were deposited onto alumina substrate by a combination of spin coating [...] Read more.
In this paper we report on the development tungsten oxide based chemiresistive sensors for the monitoring of oxygen at low temperatures (T ≤ 400 °C) in dry and humid air. The sensors were deposited onto alumina substrate by a combination of spin coating and a photolithographic process to define the sensing area. Our results show that the sensors comply with a linear relationship over a 0 to 20% concentration range, with a high response towards oxygen. The highest response was observed at 350 °C (ΔR/Ra = 7.8) in humid and in dry air (ΔR/Ra = 18). This result is a significant improvement over our previous experiments and we believe to take the concept of a metal-oxide based oxygen sensor a step closer. 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
Viewed by 193 | 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 184 | 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 [...] Read more.
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 228 | 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 [...] Read more.
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
Viewed by 197 | 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. [...] Read more.
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 Localized and In-Situ Integration of Different Nanowire Materials for Electronic Nose Applications
Proceedings 2018, 2(13), 957; https://doi.org/10.3390/proceedings2130957
Published: 11 January 2019
Viewed by 243 | PDF Full-text (628 KB) | Supplementary Files
Abstract
A new method for the site-selective synthesis of nanowires has been developed to enable the material growth with specific morphology and different compositions on one single chip. Based on a modification of the chemical vapor deposition method, the growth of nanowires on top [...] Read more.
A new method for the site-selective synthesis of nanowires has been developed to enable the material growth with specific morphology and different compositions on one single chip. Based on a modification of the chemical vapor deposition method, the growth of nanowires on top of micromembranes can be easily tuned and represents a simple and adjustable fabrication process for the direct integration of different nanowire-based resistive multifunctional devices. This proof-of-concept is exemplified by the deposition of SnO2, WO3 and Ge nanowires on the membranes of one single chip and their gas sensing responses towards different concentrations of CO, NO2 and humidity diluted in synthetic air are evaluated. The principal component analysis of the collected data allows gas identification and, thus, the system is suitable for environmental monitoring. Full article
Open AccessProceedings Room Temperature Humidity Sensor Based on Single β-Ga2O3 Nanowires
Proceedings 2018, 2(13), 958; https://doi.org/10.3390/proceedings2130958
Published: 8 January 2019
Viewed by 204 | PDF Full-text (834 KB)
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 225 | 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 [...] Read more.
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 199 | 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 246 | 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
Cited by 1 | Viewed by 245 | 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 180 | 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 [...] Read more.
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 182 | 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
Viewed by 219 | 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 270 | 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 [...] Read more.
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 197 | 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 [...] Read more.
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 201 | 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 183 | 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 214 | 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 235 | 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 130 | 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
Viewed by 226 | 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 Effective Sensor Properties of a Novel Co-Resonant Cantilever Sensor
Proceedings 2018, 2(13), 974; https://doi.org/10.3390/proceedings2130974
Published: 8 January 2019
Viewed by 216 | PDF Full-text (646 KB)
Abstract
Co-resonantly coupled cantilever sensors have recently been introduced as a very promising concept to strongly increase the sensitivity of dynamic-mode cantilever MEMS sensors (several orders of magnitude experimentally demonstrated) while maintaining the ease of detection. Mechanical coupling and eigenfrequency matching of a micro- [...] Read more.
Co-resonantly coupled cantilever sensors have recently been introduced as a very promising concept to strongly increase the sensitivity of dynamic-mode cantilever MEMS sensors (several orders of magnitude experimentally demonstrated) while maintaining the ease of detection. Mechanical coupling and eigenfrequency matching of a micro- and a nanocantilever lead to a coupled system where any interaction at the highly sensitive nanocantilever alters the oscillatory state of the entire system which is detected at the microcantilever with standard laser-based methods. The coupled system’s sensor properties are described by effective parameters which depend on the subsystems’ properties and the degree of eigenfrequency matching. Here, the focus is on the implications of the effective properties on sensor performance with regard to sensitivity and detectability, which will be illustrated by an exemplary sensor model. 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 184 | 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 [...] Read more.
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
Viewed by 215 | 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 [...] Read more.
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
Viewed by 290 | 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 [...] Read more.
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 223 | 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 [...] Read more.
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 208 | 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 [...] Read more.
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
Viewed by 238 | 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 [...] Read more.
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
Viewed by 198 | 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 [...] Read more.
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 236 | 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 [...] Read more.
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
Viewed by 246 | 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 [...] Read more.
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 237 | 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 [...] Read more.
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
Cited by 1 | Viewed by 339 | 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 [...] Read more.
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 179 | 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 [...] Read more.
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
Cited by 1 | Viewed by 222 | 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 [...] Read more.
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 192 | 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 [...] Read more.
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 225 | 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 [...] Read more.
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 199 | 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 [...] Read more.
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
Published: 13 December 2018
Viewed by 217 | 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 [...] Read more.
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 Flow Injection Analysis with Microdialysis Probes Enable Minimally Invasive and Dynamic H2O2 Measurements
Proceedings 2018, 2(13), 992; https://doi.org/10.3390/proceedings2130992
Published: 17 December 2018
Viewed by 285 | PDF Full-text (572 KB)
Abstract
This paper describes the optimization of a published flow injection analysis system coupled with microdialysis probes (MDP-FIA) for in-situ sampling and online measurements of hydrogen peroxide (H2O2). By modifying the commonly used Na2CO3 buffer by addition [...] Read more.
This paper describes the optimization of a published flow injection analysis system coupled with microdialysis probes (MDP-FIA) for in-situ sampling and online measurements of hydrogen peroxide (H2O2). By modifying the commonly used Na2CO3 buffer by addition of EDTA and a changed order in reagent injection, interfering transition metals such as Fe(II) and Fe(III) are complexed and removed from the system without interfering with the chemiluminescent reaction of the used acridinium ester and H2O2. The system was then used to monitor changes in H2O2 concentration upon microwaving seawater and filtered seawater in the presence and absence of agar. 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 378 | 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. [...] Read more.
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 Solvent Resistant O2 Sensor Integrated in Pressured Flow Reactors
Proceedings 2018, 2(13), 994; https://doi.org/10.3390/proceedings2130994
Published: 16 January 2019
Viewed by 217 | PDF Full-text (1021 KB)
Abstract
In this contribution we present an optical oxygen sensor that can easily be integrated into continuous flow reactors. The sensors are pressure resistant to up to 8 bars and are able to continuously measure oxygen for several hours in organic solvents. The dynamic [...] Read more.
In this contribution we present an optical oxygen sensor that can easily be integrated into continuous flow reactors. The sensors are pressure resistant to up to 8 bars and are able to continuously measure oxygen for several hours in organic solvents. The dynamic range was evaluated up to 42 mmol/L O2 and several calibrations showed the sensors to perform linearly according to Stern-Volmer, which allows convenient two-point calibrations. By using state-of-the-art HPLC connectors and materials the sensor can be implemented at virtually every point of a standard flow reactor. Readout is conducted via a 4-channel USB phase fluorimeter. Full article
Open AccessProceedings Characterization of a Capacitive Sensor for Particulate Matter
Proceedings 2018, 2(13), 995; https://doi.org/10.3390/proceedings2130995
Published: 17 December 2018
Viewed by 268 | PDF Full-text (510 KB)
Abstract
We characterize a novel micro-sensor with pairs of interdigitated combs of microelectrodes designed to detect particles in air. We evaluate the sensor’s response to 1 µm Polystyrene Latex (PSL) particles experimentally and crosscheck the results with simulations. Experiment and simulation show good consistency. [...] Read more.
We characterize a novel micro-sensor with pairs of interdigitated combs of microelectrodes designed to detect particles in air. We evaluate the sensor’s response to 1 µm Polystyrene Latex (PSL) particles experimentally and crosscheck the results with simulations. Experiment and simulation show good consistency. Based on the promising results we propose a redesign of the capacitive particle sensor with respect to PM2.5. Full article
Open AccessProceedings Array of MOX Nanowire Gas Sensors for Wastewater Management
Proceedings 2018, 2(13), 996; https://doi.org/10.3390/proceedings2130996
Published: 17 December 2018
Viewed by 278 | PDF Full-text (362 KB)
Abstract
Water is a common fundamental resource for life. The effects of climate change, pollution and waste make it an increasingly scarce resource. Therefore, it becomes very important to monitor water quality to identify situations of possible harm to humans. In this study, incoming [...] Read more.
Water is a common fundamental resource for life. The effects of climate change, pollution and waste make it an increasingly scarce resource. Therefore, it becomes very important to monitor water quality to identify situations of possible harm to humans. In this study, incoming wastewater of the depuration plant of A2A Ciclo Idrico in Brescia has been analyzed with an array of MOX nanowire gas sensors. In addition, GC-MS technique has been used to relate sensors responses with the emitted VOCs of the samples. The ability of the system to recognize potable water from wastewater and chemically contaminated wastewater has been found. PCA and ANN methods have been employed in order to see how samples classes cluster and to assess the capability of the device to classify them properly, respectively. 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 247 | 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 [...] Read more.
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
Viewed by 157 | 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 [...] Read more.
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 UV-Assisted Gate Bias Cycling in Gas-Sensitive Field-Effect Transistors
Proceedings 2018, 2(13), 999; https://doi.org/10.3390/proceedings2130999
Published: 17 December 2018
Viewed by 255 | PDF Full-text (512 KB)
Abstract
Static and dynamic responses of a silicon carbide field-effect transistor gas sensor have been investigated at two different gate biases in several test gases. Especially the dynamic effects are gas dependent and can be used for gas identification. The addition of ultraviolet light [...] Read more.
Static and dynamic responses of a silicon carbide field-effect transistor gas sensor have been investigated at two different gate biases in several test gases. Especially the dynamic effects are gas dependent and can be used for gas identification. The addition of ultraviolet light reduces internal electrical relaxation effects, but also introduces new, temperature-dependent effects. Full article
Open AccessProceedings Novel Design of Additively Manufactured Micromixer in a Microchannel Comprising Mounting and Sealing Elements
Proceedings 2018, 2(13), 1000; https://doi.org/10.3390/proceedings2131000
Published: 17 December 2018
Viewed by 283 | PDF Full-text (409 KB)
Abstract
An additively manufactured three-dimensional mixing element (3DME) integrated in a microchannel is presented. The 3DME increases the interfacial contact-surface by swapping the positions of the incoming streaming liquids. The novel design incorporates important design alterations to a prior prototype. These alterations significantly improve [...] Read more.
An additively manufactured three-dimensional mixing element (3DME) integrated in a microchannel is presented. The 3DME increases the interfacial contact-surface by swapping the positions of the incoming streaming liquids. The novel design incorporates important design alterations to a prior prototype. These alterations significantly improve the integration of microelements written by two-photon polymerization (2pp) into photolithographically defined microchannels. Anchor-structures for increased strength as well as a roof to compensate for height-discrepancies between the lithographically defined microchannel and the 2pp-written 3DME are addressed. These allow for a better positioning as well as an increased sealing reliability between the top of the 3DME and a PDMS-lid which in our case is used to close the microchannel. 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 381 | 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 279 | 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 [...] Read more.
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 187 | 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
Cited by 1 | Viewed by 243 | 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 Design and Testing of a Sensing System for Aero-Engine Smart Bearings
Proceedings 2018, 2(13), 1005; https://doi.org/10.3390/proceedings2131005
Published: 15 January 2019
Viewed by 284 | PDF Full-text (1624 KB)
Abstract
Smart bearings incorporating self-powered sensors and wireless data communications with intelligence in monitoring bearing conditions can help to detect early faults in aero-engine bearings. This paper presents the challenges in design and development of a sensing system with compact and low-power consumption sensors [...] Read more.
Smart bearings incorporating self-powered sensors and wireless data communications with intelligence in monitoring bearing conditions can help to detect early faults in aero-engine bearings. This paper presents the challenges in design and development of a sensing system with compact and low-power consumption sensors and the procedures for sensor performance evaluation under the requirements of aerospace standard. Industrial standard DO160 testing is necessary for preliminary testing of the smart sensing system prior to being installed in aero-engine, thus a laboratory test procedure has been developed for sensor performance evaluation for the smart aero-engine bearings in this project. As a case study, this paper presents the details and results of the accelerometer evaluation following the requirements in DO160. 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 166 | 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
Published: 13 December 2018
Viewed by 304 | 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 Development of Graphene Based Inks for Deposition via Inkjet Printing for Sensing Application
Proceedings 2018, 2(13), 1008; https://doi.org/10.3390/proceedings2131008
Published: 17 December 2018
Viewed by 243 | PDF Full-text (435 KB)
Abstract
In this work we investigate and optimize graphene based inks to achieve a stable and well-controllable jetting behavior using a DoD (Drop on Demand) inject printer which has all the required characteristics of a tool for mass production. Full article
Open AccessProceedings Extraction of Fetal Heart Rate from Maternal ECG—Non Invasive Approach for Continuous Monitoring during Labor
Proceedings 2018, 2(13), 1009; https://doi.org/10.3390/proceedings2131009
Published: 19 December 2018
Viewed by 293 | PDF Full-text (984 KB)
Abstract
Here, we propose a signal processing based approach for the extraction of the fetal heart rate (FHR) from Maternal Abdominal ECG (MAECG) in a non-invasive way. Datasets from a Physionet database has been used in this study for evaluating the performance of the [...] Read more.
Here, we propose a signal processing based approach for the extraction of the fetal heart rate (FHR) from Maternal Abdominal ECG (MAECG) in a non-invasive way. Datasets from a Physionet database has been used in this study for evaluating the performance of the proposed model that performs three major tasks; preprocessing of the MAECG signal, separation of Fetal QRS complexes from that of maternal and estimation of Fetal R peak positions. The MAECG signal is first preprocessed with improved multistep filtering techniques to detect the Maternal QRS (MQRS) complexes, which are dominant in the MAECG. A reference template is then reconstructed based on MQRS locations and removed from the preprocessed signal resulting in the raw FECG. This extracted FECG is further corrected and enhanced before obtaining the Fetal R peaks. The detection of FQRS and calculation of FHR has been compared against the reference Fetal Scalp ECG. Results indicate that the approach achieved good accuracy. 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 214 | 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 Hybrid Micro Electro Mechanical Sensor Based on Graphene Oxide/Polyvinyl Alcohol for Humidity Measurements
Proceedings 2018, 2(13), 1011; https://doi.org/10.3390/proceedings2131011
Published: 19 December 2018
Viewed by 227 | PDF Full-text (1403 KB)
Abstract
In this paper, we present a redundant micromachined sensor based on Bulk and Etch. Silicon-on-Insulator (BESOI) process for measurements of relative humidity (RH) by using Graphene-Oxide/Polyvinyl-Alcohol (GO/PVA) composite. The microsensor is a mechanical oscillator composed of a proof mass with multilayer of nanomaterials [...] Read more.
In this paper, we present a redundant micromachined sensor based on Bulk and Etch. Silicon-on-Insulator (BESOI) process for measurements of relative humidity (RH) by using Graphene-Oxide/Polyvinyl-Alcohol (GO/PVA) composite. The microsensor is a mechanical oscillator composed of a proof mass with multilayer of nanomaterials (GO/PVA) and suspended by four crab leg springs. The realized redundant approach concerns the possibility to use different readout strategies in order to estimate the same measurand: RH. This is an intriguing solution to realize a “robust measurement system”, with multiple outputs by using the GO/PVA as functional material. In presence of RH variation: (1) it changes its mass and; as consequence; a variation of the natural frequency of the oscillator can be observed in the frequency domain; (2) it also varies the conductivity which can be measured by using two integrated electrodes. The sensor has been designed; studied; modeled and experimental results demonstrate the effectiveness of our implementation. 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 216 | 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 [...] Read more.
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 183 | 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 [...] Read more.
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 159 | 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 [...] Read more.
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 Multiparametric Porcine Oocyte Deformation Characterization by Novel MEMS-Type Cytometer
Proceedings 2018, 2(13), 1015; https://doi.org/10.3390/proceedings2131015
Published: 29 December 2018
Viewed by 276 | PDF Full-text (853 KB)
Abstract
In this work for the first time MEMS-type deformation microcytometer and a new methodology for the determination of cell deformability is proposed. Novel chip design and methodology allow real-time observation of the cell deformation occurring during compression of oocytes. In addition, software-based analysis [...] Read more.
In this work for the first time MEMS-type deformation microcytometer and a new methodology for the determination of cell deformability is proposed. Novel chip design and methodology allow real-time observation of the cell deformation occurring during compression of oocytes. In addition, software-based analysis of microscopic images allows multiparametric characterization of the investigated cell toward quality assessment of the cell. 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 230 | 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 [...] Read more.
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 257 | 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 [...] Read more.
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 210 | 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 [...] Read more.
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 299 | 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 250 | 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 316 | 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
Cited by 1 | Viewed by 280 | 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 [...] Read more.
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
Cited by 1 | Viewed by 276 | 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 218 | 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 [...] Read more.
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 255 | 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 289 | 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 255 | 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 202 | 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 209 | 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 [...] Read more.
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 210 | 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 [...] Read more.
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 253 | 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 214 | 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