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Proceedings, 2018, 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 - 16 Nov 2018
Viewed by 454
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 - 03 Dec 2018
Cited by 1 | Viewed by 534
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 - 04 Dec 2018
Cited by 1 | Viewed by 721
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 - 03 Dec 2018
Viewed by 385
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 - 13 Dec 2018
Cited by 1 | Viewed by 731
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 - 14 Dec 2018
Cited by 1 | Viewed by 1231
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 - 03 Dec 2018
Viewed by 622
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 - 12 Dec 2018
Viewed by 440
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 - 04 Dec 2018
Viewed by 425
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 - 19 Dec 2018
Viewed by 470
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 - 05 Dec 2018
Cited by 2 | Viewed by 497
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 - 05 Dec 2018
Viewed by 390
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 - 30 Nov 2018
Viewed by 355
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 - 03 Dec 2018
Viewed by 631
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 - 21 Dec 2018
Viewed by 387
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 - 21 Dec 2018
Cited by 2 | Viewed by 733
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 - 10 Dec 2018
Viewed by 546
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 - 21 Dec 2018
Cited by 1 | Viewed by 589
Abstract
In this paper we present a printed, fast, high-sensitive and cheap wireless incontinence sensor [...]
Full article
Open AccessProceedings
Concave Diffraction Gratings by High-Precision Injection Moulding
Proceedings 2018, 2(13), 717; https://doi.org/10.3390/proceedings2130717 - 29 Apr 2019
Viewed by 432
Abstract
As an example of the applicable process chain, a concave grating (1175 grooves/mm) with an active area of approx. 24 mm to 24 mm has been replicated by means of electroplating and further by injection moulding with polycarbonate, resulting in a surface accuracy [...] Read more.
As an example of the applicable process chain, a concave grating (1175 grooves/mm) with an active area of approx. 24 mm to 24 mm has been replicated by means of electroplating and further by injection moulding with polycarbonate, resulting in a surface accuracy even below 4 µm peak-to-valley (PV). The obtained moulds were further metallised with bare aluminium to obtain components for optical applications. To our knowledge, this is the first time that such a large nanostructured nonplanar surface has been manufactured by injection moulding in such an accuracy. Full article
Open AccessProceedings
Polyethylene Outgassing Study for MEMS Nuclear Radiation Sensor
Proceedings 2018, 2(13), 718; https://doi.org/10.3390/proceedings2130718 - 30 Nov 2018
Viewed by 393
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 - 03 Dec 2018
Viewed by 412
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 - 08 Jan 2019
Cited by 2 | Viewed by 559
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 - 04 Dec 2018
Viewed by 400
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
Screen-Printed Microcantilevers for Environmental Sensing
Proceedings 2018, 2(13), 722; https://doi.org/10.3390/proceedings2130722 - 16 Jul 2019
Viewed by 314
Abstract
This work investigates different geometries for fully screen-printed self-actuated self-readout microcantilevers made using a sacrificial layer process. The microcantilevers are made of PZT sandwiched between two gold electrodes. Q-factors as high as 1300 are reported. Promising theoretical sensitivities are reported (1000 Hz/µg at [...] Read more.
This work investigates different geometries for fully screen-printed self-actuated self-readout microcantilevers made using a sacrificial layer process. The microcantilevers are made of PZT sandwiched between two gold electrodes. Q-factors as high as 1300 are reported. Promising theoretical sensitivities are reported (1000 Hz/µg at 620 kHz) and applications as humidity, temperature and particles sensor are explored in this work. 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 - 04 Dec 2018
Viewed by 544
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 - 21 Dec 2018
Viewed by 526
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 - 10 Dec 2018
Viewed by 384
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 - 18 Dec 2018
Cited by 1 | Viewed by 512
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 - 25 Feb 2019
Viewed by 429
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 - 13 Dec 2018
Viewed by 456
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 - 10 Dec 2018
Viewed by 383
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 - 03 Dec 2018
Cited by 1 | Viewed by 349
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 - 10 Dec 2018
Viewed by 542
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 - 18 Dec 2018
Cited by 1 | Viewed by 562
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 - 04 Dec 2018
Viewed by 486
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 - 10 Dec 2018
Viewed by 486
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 - 24 Dec 2018
Viewed by 489
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 - 04 Dec 2018
Viewed by 344
Open AccessProceedings
Platinum Based Material for Additive Technology of Gas Sensors
Proceedings 2018, 2(13), 738; https://doi.org/10.3390/proceedings2130738 - 20 Dec 2018
Viewed by 423
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 - 30 Nov 2018
Viewed by 421
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 - 03 Dec 2018
Cited by 1 | Viewed by 427
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 - 29 Nov 2018
Cited by 2 | Viewed by 597
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 - 30 Nov 2018
Cited by 2 | Viewed by 418
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 - 29 Nov 2018
Cited by 4 | Viewed by 448
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 - 06 Dec 2018
Viewed by 472
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 - 20 Nov 2018
Viewed by 429
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 - 30 Nov 2018
Viewed by 521
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 - 03 Dec 2018
Viewed by 607
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 - 23 Nov 2018
Cited by 1 | Viewed by 952
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 - 30 Nov 2018
Viewed by 439
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 - 08 Jan 2019
Viewed by 530
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 - 22 Nov 2018
Viewed by 462
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 - 06 Dec 2018
Cited by 1 | Viewed by 366
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 - 21 Nov 2018
Viewed by 374
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 - 10 Dec 2018
Viewed by 350
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 - 03 Dec 2018
Cited by 1 | Viewed by 366
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 - 03 Dec 2018
Viewed by 322
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 - 27 Nov 2018
Cited by 2 | Viewed by 488
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 - 03 Dec 2018
Viewed by 450
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 - 29 Nov 2018
Viewed by 377
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 - 10 Dec 2018
Viewed by 585
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 - 30 Nov 2018
Viewed by 370
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 - 21 Nov 2018
Cited by 4 | Viewed by 433
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 - 27 Nov 2018
Viewed by 487
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 - 24 Dec 2018
Viewed by 626
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 - 23 Nov 2018
Cited by 2 | Viewed by 413
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 - 25 Feb 2019
Viewed by 482
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 - 23 Nov 2018
Viewed by 464
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 - 28 Nov 2018
Viewed by 311
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 - 19 Dec 2018
Cited by 2 | Viewed by 530
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 - 20 Nov 2018
Viewed by 474
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 - 29 Nov 2018
Cited by 2 | Viewed by 424
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 - 21 Nov 2018
Viewed by 414
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 - 10 Dec 2018
Cited by 2 | Viewed by 526
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 - 10 Dec 2018
Cited by 2 | Viewed by 372
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 - 10 Dec 2018
Cited by 2 | Viewed by 392
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 - 10 Dec 2018
Cited by 1 | Viewed by 578
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 - 13 Dec 2018
Cited by 1 | Viewed by 508
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 - 26 Dec 2018
Viewed by 587
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 - 10 Dec 2018
Viewed by 432
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 - 23 Nov 2018
Cited by 1 | Viewed by 587
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 - 23 Nov 2018
Viewed by 592
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 - 17 Dec 2018
Viewed by 532
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 - 23 Nov 2018
Cited by 2 | Viewed by 482
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 - 23 Nov 2018
Cited by 2 | Viewed by 475
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 - 23 Nov 2018
Viewed by 464
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 - 03 Dec 2018
Viewed by 562
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 - 22 Nov 2018
Viewed by 442
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 - 04 Dec 2018
Viewed by 400
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 - 21 Dec 2018
Cited by 4 | Viewed by 650
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 - 27 Nov 2018
Viewed by 628
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 - 22 Nov 2018
Viewed by 431
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 - 30 Nov 2018
Viewed by 418
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 - 10 Dec 2018
Viewed by 385
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 - 22 Nov 2018
Cited by 1 | Viewed by 1224
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 - 30 Nov 2018
Viewed by 513
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 - 30 Nov 2018
Cited by 1 | Viewed by 508
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 - 26 Nov 2018
Cited by 1 | Viewed by 405
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 - 30 Nov 2018
Viewed by 381
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 - 30 Nov 2018
Cited by 1 | Viewed by 406
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 - 21 Nov 2018
Viewed by 430
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 - 03 Jan 2019
Viewed by 605
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 - 22 Nov 2018
Viewed by 477
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 - 21 Nov 2018
Cited by 1 | Viewed by 489
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 - 06 Dec 2018
Viewed by 479
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 - 13 Dec 2018
Cited by 2 | Viewed by 769
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 - 23 Nov 2018
Viewed by 501
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 - 30 Nov 2018
Viewed by 374
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 - 08 Jan 2019
Viewed by 437
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 - 30 Nov 2018
Viewed by 515
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 - 11 Dec 2018
Viewed by 615
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 - 04 Dec 2018
Cited by 1 | Viewed by 466
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 - 04 Dec 2018
Viewed by 364
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 - 13 Dec 2018
Cited by 1 | Viewed by 594
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 - 30 Nov 2018
Cited by 1 | Viewed by 390
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 - 22 Jan 2019
Viewed by 664
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 - 10 Dec 2018
Cited by 1 | Viewed by 576
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 - 04 Dec 2018
Viewed by 433
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 - 31 Jan 2019
Viewed by 630
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 - 07 Dec 2018
Cited by 1 | Viewed by 424
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 - 09 Jan 2019
Cited by 4 | Viewed by 1013
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 - 24 Dec 2018
Cited by 2 | Viewed by 651
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 - 07 Dec 2018
Cited by 1 | Viewed by 548
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 - 11 Dec 2018
Viewed by 368
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 - 10 Dec 2018
Viewed by 475
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 - 10 Dec 2018
Cited by 1 | Viewed by 474
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 - 19 Feb 2019
Viewed by 421
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 - 03 Dec 2018
Cited by 1 | Viewed by 490
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 - 04 Dec 2018
Cited by 1 | Viewed by 607
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 - 19 Dec 2018
Viewed by 409
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 - 04 Dec 2018
Viewed by 403
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 - 04 Dec 2018
Viewed by 427
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 - 21 Dec 2018
Cited by 4 | Viewed by 551
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 - 26 Dec 2018
Viewed by 478
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 - 04 Dec 2018
Viewed by 563
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 - 04 Dec 2018
Viewed by 421
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 - 03 Dec 2018
Viewed by 525
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 - 03 Dec 2018
Viewed by 378
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 - 03 Dec 2018
Viewed by 352
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 - 03 Dec 2018
Cited by 1 | Viewed by 500
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 - 03 Dec 2018
Viewed by 596
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 - 11 Dec 2018
Viewed by 449
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 - 03 Dec 2018
Cited by 1 | Viewed by 548
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 - 04 Dec 2018
Cited by 2 | Viewed by 586
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 - 04 Dec 2018
Cited by 1 | Viewed by 411
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 - 17 Jan 2019
Viewed by 524
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 - 06 Dec 2018
Cited by 1 | Viewed by 783
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 - 20 Nov 2018
Viewed by 472
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 - 20 Nov 2018
Cited by 2 | Viewed by 500
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 - 21 Nov 2018
Viewed by 525
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 - 20 Nov 2018
Cited by 1 | Viewed by 473
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 - 20 Nov 2018
Viewed by 564
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 - 20 Nov 2018
Cited by 1 | Viewed by 425
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 - 29 Nov 2018
Viewed by 567
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 - 26 Nov 2018
Viewed by 455
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 - 21 Nov 2018
Viewed by 551
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 - 23 Nov 2018
Cited by 1 | Viewed by 451
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 - 28 Nov 2018
Viewed by 367
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 - 21 Nov 2018
Viewed by 497
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 - 21 Nov 2018
Viewed by 550
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 - 21 Nov 2018
Cited by 1 | Viewed by 783
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 - 03 Dec 2018
Viewed by 429
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 - 23 Nov 2018
Cited by 2 | Viewed by 514
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 - 23 Nov 2018
Viewed by 422
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 - 26 Nov 2018
Viewed by 499
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 - 19 Dec 2018
Viewed by 588
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 - 26 Nov 2018
Cited by 1 | Viewed by 463
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 - 05 Dec 2018
Viewed by 436
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 - 30 Nov 2018
Cited by 1 | Viewed by 423
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 - 27 Nov 2018
Viewed by 415
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 - 30 Nov 2018
Viewed by 375
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 - 05 Dec 2018
Cited by 2 | Viewed by 782
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 - 22 Nov 2018
Cited by 3 | Viewed by 542
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 - 03 Dec 2018
Viewed by 462
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 - 29 Nov 2018
Cited by 1 | Viewed by 585
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 - 10 Dec 2018
Viewed by 400
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 - 21 Dec 2018
Cited by 1 | Viewed by 624
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 - 28 Nov 2018
Viewed by 625
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 - 29 Nov 2018
Viewed by 474
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 - 23 Nov 2018
Viewed by 467
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 - 30 Nov 2018
Cited by 1 | Viewed by 518
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 - 23 Nov 2018
Cited by 4 | Viewed by 469
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 - 11 Feb 2019
Cited by 1 | Viewed by 595
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 - 21 Nov 2018
Viewed by 586
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 - 21 Nov 2018
Viewed by 479
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 - 21 Nov 2018
Cited by 1 | Viewed by 500
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 - 06 Dec 2018
Viewed by 614
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 - 28 Nov 2018
Viewed by 394
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 - 06 Dec 2018
Viewed by 553
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 - 27 Nov 2018
Viewed by 421
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 - 27 Nov 2018
Cited by 2 | Viewed by 442
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 - 29 Nov 2018
Cited by 1 | Viewed by 495
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 - 05 Dec 2018
Viewed by 459
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 - 30 Nov 2018
Cited by 3 | Viewed by 701
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 - 21 Dec 2018
Viewed by 456
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 - 30 Nov 2018
Cited by 1 | Viewed by 501
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 - 11 Dec 2018
Viewed by 565
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 - 28 Nov 2018
Viewed by 463
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 - 29 Nov 2018
Viewed by 416
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 - 26 Nov 2018
Cited by 1 | Viewed by 529
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 - 23 Nov 2018
Cited by 2 | Viewed by 388
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 - 26 Nov 2018
Viewed by 366
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 - 27 Nov 2018
Viewed by 579
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 - 29 Nov 2018
Cited by 2 | Viewed by 1858
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 - 16 Jan 2019
Cited by 3 | Viewed by 577
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 - 27 Nov 2018
Cited by 1 | Viewed by 680
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 - 26 Nov 2018
Cited by 1 | Viewed by 465
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 - 23 Nov 2018
Viewed by 368
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 - 27 Nov 2018
Viewed by 572
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 - 27 Nov 2018
Viewed by 553
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 - 24 Dec 2018
Viewed by 463
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
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