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Proceedings, Volume 1, Eurosensors 2017

Proceedings of Eurosensors 2017

Paris, France | 3–6 September 2017

Issue Editors: Jean-Paul Viricelle, Christophe Pijolat and Mathilde Rieu


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Cover Story This issue of Proceedings gathers papers presented at EUROSENSORS 2017, the XXXI edition (Paris, [...] Read more.
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Open AccessEditorial Introduction to Eurosensors 2017, Paris, 3–6 September 2017
Proceedings 2017, 1(4), 1097; doi:10.3390/proceedings1041097
Published: 21 November 2017
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Open AccessProceedings Electromagnetic Characterization and Simulation of a Carbonate Buffer System on a Microwave Biosensor
Proceedings 2017, 1(4), 276; doi:10.3390/proceedings1040276
Published: 17 August 2017
PDF Full-text (546 KB)
Abstract
In order to develop a fast, sensitive and easy-to-produce biosensor, a high-quality microwave split-ring resonator is going to be developed. In the final sensing device, a blood sample will be placed as a droplet on the sensitive area of the sensor. In case
[...] Read more.
In order to develop a fast, sensitive and easy-to-produce biosensor, a high-quality microwave split-ring resonator is going to be developed. In the final sensing device, a blood sample will be placed as a droplet on the sensitive area of the sensor. In case of specific target biomolecules binding a shift in resonance frequency will be induced due to the effective permittivity change. This shift in resonance frequency depends on the concentration of biomolecules and is therefore quantitative. The aim of this work is to find a position for the bio-functionalization that providesa measurable frequency shift when the analyte is added. Different areas are tested experimentally and via simulations. Two buffer solutions are used which have to be characterized in terms of its electromagnetic properties in advance. This preliminary study should pave the way for the measurements in real human samples such as serum or plasma. Full article
Open AccessProceedings Two-Directional Operation of Bistable Latchable Micro Switch Actuated by a Single Electrode
Proceedings 2017, 1(4), 277; doi:10.3390/proceedings1040277
Published: 16 August 2017
PDF Full-text (538 KB)
Abstract
Curved micromechanical beams are a versatile platform for exploring multistable behavior, with potential applications in mechanical based logic elements and electrical and optical switches. Here we demonstrate bidirectional electrostatic actuation of a bistable, latched, micromechanical beam by the same electrode, which was used
[...] Read more.
Curved micromechanical beams are a versatile platform for exploring multistable behavior, with potential applications in mechanical based logic elements and electrical and optical switches. Here we demonstrate bidirectional electrostatic actuation of a bistable, latched, micromechanical beam by the same electrode, which was used for the snap-through switching of the device. The release of the mechanically-latched beam is achieved by pre-loading the structure using a rising voltage applied to the electrode, followed by a sudden decrease of the voltage. This abrupt removal of the loading results in a transient response and dynamic snap-back of the beam. Full article
Open AccessProceedings Modelling New Techniques for Improving Separation in Miniature Capillary- and Planar-Based Capillary Electrophoresis Systems
Proceedings 2017, 1(4), 278; doi:10.3390/proceedings1040278
Published: 16 August 2017
PDF Full-text (1030 KB)
Abstract
The capillary/channel length is an important factor in capillary electrophoresis (CE) systems since it is directly related to the amount of separation attainable. In this work we present methods to increase the effective channel length without the need to modify the physical channel
[...] Read more.
The capillary/channel length is an important factor in capillary electrophoresis (CE) systems since it is directly related to the amount of separation attainable. In this work we present methods to increase the effective channel length without the need to modify the physical channel length. Using an electrode located close to the capillary surface it is possible to dynamically modify zeta-potential and therefore the electroosmotic flow (EOF). By controlling the EOF, certain ionic species within a sample can be held in a short channel whilst other species migrate along the channel. Alternatively the sample can be transported back and forth along the active channel length until sufficient separation has been attained. CE enables detailed analysis of a sample’s composition and this is of interest to a range of applications. Full article
Open AccessProceedings Analytical Model of Double Barrier THz Rectifier
Proceedings 2017, 1(4), 279; doi:10.3390/proceedings1040279
Published: 31 August 2017
PDF Full-text (298 KB)
Abstract
The application of the new structure to the complex field of THz receivers requires the availability of an analytical model, reliable and able to highlight the dependence on the parameters of the physical structure. We present a model of the rectification capability of
[...] Read more.
The application of the new structure to the complex field of THz receivers requires the availability of an analytical model, reliable and able to highlight the dependence on the parameters of the physical structure. We present a model of the rectification capability of the double barrier Terahertz radiation (THz) detector, a CMOS compatible structurer. The model is based on the hydrodynamic semiconductor equations; solved in the small signal approximation. The model highlights the high frequency dynamics of carriers in the structure; and furnishes new insight on the origin of the self-mixing rectification process. Full article
Open AccessProceedings Geometrical Optimisation of Diode-Based Calorimetric Thermal Flow Sensors through Multiphysics Finite Element Modelling
Proceedings 2017, 1(4), 280; doi:10.3390/proceedings1040280
Published: 11 August 2017
PDF Full-text (1398 KB)
Abstract
For the first time, 3D multiphysics finite element modelling has been used to optimise the geometry of a calorimetric thermal flow sensor. The model involves and couples three physics domains: electric, thermal and fluid mechanics. The model is validated against experimental data obtained
[...] Read more.
For the first time, 3D multiphysics finite element modelling has been used to optimise the geometry of a calorimetric thermal flow sensor. The model involves and couples three physics domains: electric, thermal and fluid mechanics. The model is validated against experimental data obtained from a thermoelectronic flow sensor comprising of a tungsten heating resistor and temperature sensing diodes. Upstream and downstream diodes measure the temperature change caused by the asymmetric thermal profile when gas flow is introduced. The optimum distance between the diodes and the heater is shown along with the advantages of altering heater and membrane geometries, providing the knowledge for application-driven sensor optimisation. Full article
Open AccessProceedings Modelling Cross Axis Sensitivity in MEMS Coriolis Vibratory Gyroscopes
Proceedings 2017, 1(4), 281; doi:10.3390/proceedings1040281
Published: 17 August 2017
PDF Full-text (626 KB)
Abstract
In this paper a Cross Axis evaluation methodology is presented. The Cross Axis Sensitivity value depends on backend testing position tolerances as well as technological features and design properties of the MEMS gyroscope. A numerical model was developed to take into account the
[...] Read more.
In this paper a Cross Axis evaluation methodology is presented. The Cross Axis Sensitivity value depends on backend testing position tolerances as well as technological features and design properties of the MEMS gyroscope. A numerical model was developed to take into account the sources of cross axis related to the last two contributions, not considering backend tolerances. Given a specific structure for the AM gyroscope, the asymmetries in the MEMS structure are acknowledged as the main sources for the cross axis. The results of the harmonic FEM simulations were finally compared with real testing data, thus proving the validity of the developed FEM model. Full article
Open AccessProceedings Reduction of Electrostatic Control Voltage with a Tri-Electrode Actuator
Proceedings 2017, 1(4), 282; doi:10.3390/proceedings1040282
Published: 11 August 2017
PDF Full-text (1029 KB)
Abstract
We present a new tri-electrode topology for reducing the control voltage for electrostatic actuators. Conventional parallel plate actuators are dual-electrode systems, formed by the MEMS structure and the drive electrode. By placing a perforated intermediate electrode between these elements, a tri-electrode configuration is
[...] Read more.
We present a new tri-electrode topology for reducing the control voltage for electrostatic actuators. Conventional parallel plate actuators are dual-electrode systems, formed by the MEMS structure and the drive electrode. By placing a perforated intermediate electrode between these elements, a tri-electrode configuration is formed. This topology enables a low voltage on the intermediate electrode to modulate the electrostatic force on the MEMS device, while the higher voltage on the drive electrode remains fixed. Results presented show that in comparison to conventional parallel plate electrostatic actuators, the intermediate electrode’s modulating voltage can be as low as 20% of normal, while still providing the full actuation stroke. Full article
Open AccessProceedings Humidity Sensitivity and Coil Design of a High-Precision Eddy-Current Displacement Sensor
Proceedings 2017, 1(4), 283; doi:10.3390/proceedings1040283
Published: 28 August 2017
PDF Full-text (621 KB)
Abstract
Unlike capacitive displacement sensors, Eddy-Current Displacement Sensors (ECDSs) possess an inherently low sensitivity to environmental conditions, such as the humidity of the ambient air. By elevating the excitation frequency it is possible to mitigate their major limitations regarding stability and resolution, making them
[...] Read more.
Unlike capacitive displacement sensors, Eddy-Current Displacement Sensors (ECDSs) possess an inherently low sensitivity to environmental conditions, such as the humidity of the ambient air. By elevating the excitation frequency it is possible to mitigate their major limitations regarding stability and resolution, making them of interest for high-precision displacement sensing. However, by increasing the excitation frequency, ECDSs become less immune to environmental conditions, due to the inevitable parasitic capacitance of the sensing coil. In this work, we formulate a requirement for the minimum Self-Resonance Frequency (SRF) of the coil, based on the specified humidity variation and the allowable displacement error. This requirement provides an input for the design of the high-precision ECDS probe. Full article
Open AccessProceedings Analytical Calculation of Falling Droplets from Cylindrical Capillaries
Proceedings 2017, 1(4), 284; doi:10.3390/proceedings1040284
Published: 7 September 2017
PDF Full-text (319 KB)
Abstract
Existing investigations to estimate different properties of falling droplets are based on empirical data or complex mathematical approaches. This paper presents a new simple analytical approach to calculate selected properties of droplets, in particular the volume and frequency of falling droplets, out of
[...] Read more.
Existing investigations to estimate different properties of falling droplets are based on empirical data or complex mathematical approaches. This paper presents a new simple analytical approach to calculate selected properties of droplets, in particular the volume and frequency of falling droplets, out of a thin vertical cylindrical capillary. The fluid-reservoir is located above the capillary and provides a constant flow into the droplet. This leads to drop formation times less than one second. The results of the calculation are validated by numerical simulations and experiments. Full article
Open AccessProceedings High Precision Accelerometer with Integrated Thermal Sensor
Proceedings 2017, 1(4), 285; doi:10.3390/proceedings1040285
Published: 24 August 2017
PDF Full-text (2069 KB)
Abstract
This paper investigates the design of a Vibrating Beam Accelerometer (VBA) with a resolution of 50 nano-g combined with an integrated thermal sensor. Despite quartz intrinsic thermal stability, the time delay between vibrating beam’s temperature and package’s temperature gives way to unwanted transient
[...] Read more.
This paper investigates the design of a Vibrating Beam Accelerometer (VBA) with a resolution of 50 nano-g combined with an integrated thermal sensor. Despite quartz intrinsic thermal stability, the time delay between vibrating beam’s temperature and package’s temperature gives way to unwanted transient thermal behavior and thus bias instability. The aim of this study is to include a thermal sensor consisting in a torsional resonator directly at the center of the beam. Previous work demonstrated the feasibility of such integration on a tactical class accelerometer but also highlighted limitations like high motional resistance of the torsional resonator. Benefits of the in-situ temperature sensor are investigated thanks to finite element analysis of the accelerometer transient thermal behavior, which shall be compared to measurements on actual cells. Full article
Open AccessProceedings Efficient Vertical-Cavity Mid-IR Thermal Radiation to Silicon-Slab Waveguide Coupling Using a Shallow Blazed Grating
Proceedings 2017, 1(4), 286; doi:10.3390/proceedings1040286
Published: 23 August 2017
PDF Full-text (1673 KB)
Abstract
In this work we investigate the coupling of radiation originating from a vertical-cavity enhanced thermal emitter (VERTE) into an optical waveguide, which can, for instance, act as a sensing element. We present full wave modelling results demonstrating highly efficient emitter-to-waveguide diffraction coupling at
[...] Read more.
In this work we investigate the coupling of radiation originating from a vertical-cavity enhanced thermal emitter (VERTE) into an optical waveguide, which can, for instance, act as a sensing element. We present full wave modelling results demonstrating highly efficient emitter-to-waveguide diffraction coupling at multiple angles using the previously designed VERTE together with a shallow blazed grating. It is shown that the coherent and dispersive thermal emission of the VERTE concept is well suited to achieve highly efficient and integrated mode coupling in the mid IR region. Full article
Open AccessProceedings Simulating Rain Droplets Influence on Distance Measurement with a Time-of-Flight Camera Sensor
Proceedings 2017, 1(4), 287; doi:10.3390/proceedings1040287
Published: 29 August 2017
PDF Full-text (5991 KB)
Abstract
Time-of-Flight (ToF) camera sensors measure simultaneously the light intensity and the scene distance on a pixel basis. Environmental effects, like rain droplets between the scene and the ToF camera, have an impact on the distance accuracy of the sensor. Optical raytracing simulations were
[...] Read more.
Time-of-Flight (ToF) camera sensors measure simultaneously the light intensity and the scene distance on a pixel basis. Environmental effects, like rain droplets between the scene and the ToF camera, have an impact on the distance accuracy of the sensor. Optical raytracing simulations were performed to study rain influence in detail. The 3D simulation setup comprises all relevant elements including the sensor design, the object/scene geometry and a model for the environmental conditions. Specifically, a setup with small-angle ToF camera optics is investigated and a comparison of the influence of several typical rain intensities is presented. The simulation results serve as an input for developing error-compensation algorithms. Full article
Open AccessProceedings Towards Nanostructured ITO-Based Electrochemical Sensors: Fabrication, Characterization and Functionalization
Proceedings 2017, 1(4), 288; doi:10.3390/proceedings1040288
Published: 16 August 2017
PDF Full-text (852 KB)
Abstract
The need for miniaturized, low-cost and ultrasensitive electrochemical sensors has motivated the search and study of new nanostructured materials. We propose nanostructured indium tin oxide (ITO) electrodes as a promising platform due to their good electrical conductivity, transparency to visible wavelengths and high
[...] Read more.
The need for miniaturized, low-cost and ultrasensitive electrochemical sensors has motivated the search and study of new nanostructured materials. We propose nanostructured indium tin oxide (ITO) electrodes as a promising platform due to their good electrical conductivity, transparency to visible wavelengths and high surface-to-volume ratio. The nanostructured electrodes were fabricated by electron beam evaporation, and electrochemical techniques were used to quantify more than a 40% increase in electrochemical surface area compared to thin ITO films. The electrodes were derivatized with organosilanes and coated with a molecule providing redox activity. Indeed, an increase in detectability of more than 400% was observed with respect to thin films, indicating the potential viability of nanostructured ITO-based electrochemical biosensors. Full article
Open AccessProceedings Toward the Analysis of Mitochondria Isolated from Leukemic Cells with Electrochemically Instrumented Microwell Arrays
Proceedings 2017, 1(4), 289; doi:10.3390/proceedings1040289
Published: 25 August 2017
PDF Full-text (470 KB)
Abstract
This work deals with the development of electrochemical transducers for the analysis of the metabolic status of mitochondria isolated from leukemic cells. It proposes the use of ring nanoelectrodes (RNE) integrated into microwell arrays for the simultaneous monitoring of the oxygen (O2
[...] Read more.
This work deals with the development of electrochemical transducers for the analysis of the metabolic status of mitochondria isolated from leukemic cells. It proposes the use of ring nanoelectrodes (RNE) integrated into microwell arrays for the simultaneous monitoring of the oxygen (O2) consumption and the hydrogen peroxide (H2O2) production. The sensor enabled the real-time recording of the oxygen consumption of approximately 10,000 isolated mitochondria. Solutions are now proposed to detect H2O2 production and to reduce the number of mitochondria under test, targeting the single mitochondrion analysis. Full article
Open AccessProceedings Fabrication of ZnO Nanorods on MEMS Piezoresistive Silicon Microcantilevers for Environmental Monitoring
Proceedings 2017, 1(4), 290; doi:10.3390/proceedings1040290
Published: 16 August 2017
PDF Full-text (1430 KB)
Abstract
In this study, a ZnO nanorods (NRs) patterned MEMS piezoresistive silicon micro-cantilever was fabricated as environmental monitor. The fabrication starts from bulk silicon, utilizing photolithography, diffusion, inductively coupled plasma (ICP) cryogenic dry etching, Zinc DC-sputtering, and chemical bath deposition (CBD) etc. This sensor
[...] Read more.
In this study, a ZnO nanorods (NRs) patterned MEMS piezoresistive silicon micro-cantilever was fabricated as environmental monitor. The fabrication starts from bulk silicon, utilizing photolithography, diffusion, inductively coupled plasma (ICP) cryogenic dry etching, Zinc DC-sputtering, and chemical bath deposition (CBD) etc. This sensor shows a humidity sensitivity value of 6.35 ± 0.27 ppm/RH% at 25 °C in the range from 30% RH to 80% RH. Full article
Open AccessProceedings Single-Step CMOS Compatible Fabrication of High Aspect Ratio Microchannels Embedded in Silicon
Proceedings 2017, 1(4), 291; doi:10.3390/proceedings1040291
Published: 11 August 2017
PDF Full-text (1025 KB)
Abstract
This paper presents a new method for the CMOS compatible fabrication of microchannels integrated into a silicon substrate. In a single-step DRIE process (Deep Reactive Ion Etching) a network of microchannels with High Aspect Ratio (HAR) up to 10, can be etched in
[...] Read more.
This paper presents a new method for the CMOS compatible fabrication of microchannels integrated into a silicon substrate. In a single-step DRIE process (Deep Reactive Ion Etching) a network of microchannels with High Aspect Ratio (HAR) up to 10, can be etched in a silicon substrate through a mesh mask. In the same single etching step, multidimensional microchannels with various dimensions (width, length, and depth) can be obtained by tuning the process and design parameters. These fully embedded structures enable further wafer processing and integration of electronic components like sensors and actuators in wafers with microchannels. Full article
Open AccessProceedings Formation of Crumpled Graphene for Flexible Strain Sensor
Proceedings 2017, 1(4), 292; doi:10.3390/proceedings1040292
Published: 21 August 2017
PDF Full-text (1067 KB)
Abstract
Studying the strain of materials on a small scale is very important for applications in strain sensors. Previous studies show that graphene is a promising candidate for strain sensors because of its extraordinary physical and electrical properties. However, these studies were limited to
[...] Read more.
Studying the strain of materials on a small scale is very important for applications in strain sensors. Previous studies show that graphene is a promising candidate for strain sensors because of its extraordinary physical and electrical properties. However, these studies were limited to strain applied in a single direction. In this study, flexible strain sensors based on graphene were fabricated and evaluated for strain applied in two directions. For this, the CVD graphene was crumpled with the help of a pre-stretched silicone film. The preliminary results for applied strain in one direction by keeping a fixed strain in the other direction show a significant change in the resistance, up to 20 kΩ. Full article
Open AccessProceedings Hierarchically Assembled Titania Based Nanostructures: Innovative and Efficient Strategies for the Synthesis and the Improvement of Sensing Properties
Proceedings 2017, 1(4), 293; doi:10.3390/proceedings1040293
Published: 17 August 2017
PDF Full-text (1377 KB)
Abstract
We have developed innovative and efficient strategy for the preparation and improvement of sensing performance of well-ordered titania nanotubes. We have synthesized different materials based on titania nanotubes using cost-effective techniques. The morphological and structural analyses of the prepared materials have been carried
[...] Read more.
We have developed innovative and efficient strategy for the preparation and improvement of sensing performance of well-ordered titania nanotubes. We have synthesized different materials based on titania nanotubes using cost-effective techniques. The morphological and structural analyses of the prepared materials have been carried out. The sensing properties of the structures have been studied towards NO2. Investigations have shown the functionalization process has crucial effect on sensing properties of titania nanotubes. The obtained results demonstrate that the prepared structures are promising for the potential applications in the area of chemical sensors for the environmental monitoring. Full article
Open AccessProceedings VO2: A Phase Change Material for Micromechanics
Proceedings 2017, 1(4), 294; doi:10.3390/proceedings1040294
Published: 11 August 2017
PDF Full-text (588 KB)
Abstract
Micro- and nano-mechanical systems may take advantage from using materials having multiple functional characteristics. VO2 is a compound characterised by a solid state phase transition (SSPT) just above room temperature, consisting in a concurrent metal-insulator transition and a change of lattice symmetry
[...] Read more.
Micro- and nano-mechanical systems may take advantage from using materials having multiple functional characteristics. VO2 is a compound characterised by a solid state phase transition (SSPT) just above room temperature, consisting in a concurrent metal-insulator transition and a change of lattice symmetry and parameters. Here, the combination of non-linear electrical response and structural changes is employed to realise a novel high-frequency mechanical actuation scheme, showing direct conversion from DC voltage to mechanical excitation in the MHz range and selective activation of the different mechanical modes of a microstructure. Full article
Open AccessProceedings Silicon Sacrificial Layer Technology for the Production of 3D MEMS (EPyC Process)
Proceedings 2017, 1(4), 295; doi:10.3390/proceedings1040295
Published: 11 August 2017
PDF Full-text (1056 KB)
Abstract
The EPyC process uses silicon sacrificial layer technology, which makes it possible to generate high volume sacrificial structures of up to 100 microns thickness. The biggest challenge is the rapid and complete removal of the 3D sacrificial structure at the end of the
[...] Read more.
The EPyC process uses silicon sacrificial layer technology, which makes it possible to generate high volume sacrificial structures of up to 100 microns thickness. The biggest challenge is the rapid and complete removal of the 3D sacrificial structure at the end of the process. This paper examines and compares in detail two silicon dry etching methods to optimize a new silicon etching process for successful EPyC manufacturing Full article
Open AccessProceedings Multilayer Micromechanics Process with Thick Functional Layers (EPyC40)
Proceedings 2017, 1(4), 296; doi:10.3390/proceedings1040296
Published: 17 August 2017
PDF Full-text (814 KB)
Abstract
The EPyC process (Epi-Poly-Cycle) (by Robert Bosch GmbH) opens up unique opportunities for manufacturing complex 3D MEMS structures having high effectiveness in small space. EPyC40 is an EPyC process with up to 40 μm thick polysilicon layers and sacrificial silicon technique. For successful
[...] Read more.
The EPyC process (Epi-Poly-Cycle) (by Robert Bosch GmbH) opens up unique opportunities for manufacturing complex 3D MEMS structures having high effectiveness in small space. EPyC40 is an EPyC process with up to 40 μm thick polysilicon layers and sacrificial silicon technique. For successful manufacturing a 40 μm EPyC the epitaxial polysilicon layer must be electrically and mechanically optimized. A vertical deep trench patterns the functional and sacrificial areas. A passivation must be deposited homogeneously and has to be tight and robust towards silicon-etching gases. For more than one cycle it is necessary to tailor the layer stress of the epitaxial polysilicon and the wafer-bow. The full process for stacking up 5 EPyC cycles with two 40 μm epitaxial polysilicon layers was investigated in detail. A true 3D MEMS device providing high z deflection by use of a vertical comb drive with 40 μm electrodes was built up successfully to prove the feasibility of the EPyC process. Full article
Open AccessProceedings Porous Silicon Carbide for MEMS
Proceedings 2017, 1(4), 297; doi:10.3390/proceedings1040297
Published: 30 August 2017
PDF Full-text (1330 KB)
Abstract
Metal assisted photochemical etching (MAPCE) of 4H Silicon Carbide (SiC) was utilized to generate locally defined porous areas on single crystalline substrates. Therefore, Platinum (Pt) was sputter deposited on 4H-SiC substrates and patterned with photolithography and lift off. Etching was performed by immersing
[...] Read more.
Metal assisted photochemical etching (MAPCE) of 4H Silicon Carbide (SiC) was utilized to generate locally defined porous areas on single crystalline substrates. Therefore, Platinum (Pt) was sputter deposited on 4H-SiC substrates and patterned with photolithography and lift off. Etching was performed by immersing the Pt coated samples into an etching solution containing sodium persulphate and hydrofluoric acid. UV light irradiation was necessary for charge carrier generation while the Pt served as local cathode. The generated porous areas can be used for the generation of integrated cavities in the single crystalline SiC substrates when covered with a chemical vapor deposited thin film of poly-crystalline SiC. Full article
Open AccessProceedings Integration of Silica Aerogels in Microfluidic Chips
Proceedings 2017, 1(4), 298; doi:10.3390/proceedings1040298
Published: 9 August 2017
PDF Full-text (593 KB)
Abstract
This paper reports a method to integrate silica aerogels monolithically in microfluidic chips. Silica Aerogel is a highly porous bulk material. The gel was synthesized from tetraethyl orthosilicate by a sol-gel process. Polyethylene glycol and an extended aging period were used to strengthen
[...] Read more.
This paper reports a method to integrate silica aerogels monolithically in microfluidic chips. Silica Aerogel is a highly porous bulk material. The gel was synthesized from tetraethyl orthosilicate by a sol-gel process. Polyethylene glycol and an extended aging period were used to strengthen the matrix minimizing gel shrinkage. This technique allows alcogel structures with high strength and stiffness that withstand high pressure during the subcritical drying process. Hexamethyldisilazane provides for hydrophobizing and prevents the formation of siloxane bonds during the drying process. The resulting transparent aerogels reach porosities of 85%, pore diameters around 50 nm and contact angles of 136°. Full article
Open AccessProceedings A Simple Method to Allow Parylene-C Coatings on Gold Substrates
Proceedings 2017, 1(4), 299; doi:10.3390/proceedings1040299
Published: 23 August 2017
PDF Full-text (604 KB)
Abstract
Parylene-C, a biocompatible coating material, does not adhere well to metals. This is problematic especially for biomedical devices containing gold structures. In this contribution, we present a simple method to adhere Parylene-C to gold-coated substrates based on thiol-based adhesion promoters. The effectiveness of
[...] Read more.
Parylene-C, a biocompatible coating material, does not adhere well to metals. This is problematic especially for biomedical devices containing gold structures. In this contribution, we present a simple method to adhere Parylene-C to gold-coated substrates based on thiol-based adhesion promoters. The effectiveness of the adhesion promoters has been demonstrated by pull-tests on autoclaved Parylene-C coated gold-substrates. Full article
Open AccessProceedings Driving and Sensing M/NEMS Flexural Vibration Using Dielectric Transduction
Proceedings 2017, 1(4), 300; doi:10.3390/proceedings1040300
Published: 25 August 2017
PDF Full-text (871 KB)
Abstract
We show that nanometer-scale dielectric thin films can act as efficient electromechanical transducers to simultaneously drive and sense the vibration of the first flexural mode of micro/nano-cantilevers. Here, 16 μm-long, 5 μm-wide and 350 nm-thick cantilevers are actuated by a 15 nm-thick silicon
[...] Read more.
We show that nanometer-scale dielectric thin films can act as efficient electromechanical transducers to simultaneously drive and sense the vibration of the first flexural mode of micro/nano-cantilevers. Here, 16 μm-long, 5 μm-wide and 350 nm-thick cantilevers are actuated by a 15 nm-thick silicon nitride layer, and electrically detected by charge measurement at megahertz frequencies. The displacement was also checked by optical interferometry, and the electromechanical transduction efficiency is extracted and compared to an analytical modelling. Full article
Open AccessProceedings Electrostatically Actuated Membranes of Cross-Linked Gold Nanoparticles: Novel Concepts for Electromechanical Gas Sensors
Proceedings 2017, 1(4), 301; doi:10.3390/proceedings1040301
Published: 29 August 2017
PDF Full-text (1474 KB)
Abstract
We report the preparation of freestanding membranes of cross-linked gold nanoparticles (GNPs) and demonstrate their application as electromechanical sensors for volatile organic compounds (VOCs). First, we show that the fundamental vibrational mode frequency of electrostatically excited GNP-membranes shifts significantly when exposing them to
[...] Read more.
We report the preparation of freestanding membranes of cross-linked gold nanoparticles (GNPs) and demonstrate their application as electromechanical sensors for volatile organic compounds (VOCs). First, we show that the fundamental vibrational mode frequency of electrostatically excited GNP-membranes shifts significantly when exposing them to solvent vapors. We attribute this effect mainly to the reduction of the membranes’ pre-stress. Second, the relief in pre-stress upon analyte sorption can also be detected via quasi-static actuation of the membranes. In this case, the increase of the deflection amplitudes at constant bias voltages can be measured as the sensor signal and correlated to the analyte’s concentration. Additionally, we propose a facile route to the fabrication of such hybrid MEMS/NEMS sensors using layer-by-layer spin-coating and contact printing. Full article
Open AccessProceedings Microfabrication of Embedding a Flexible Parylene-Based Microelectrode Array within Body-on-a-Chip
Proceedings 2017, 1(4), 302; doi:10.3390/proceedings1040302
Published: 24 August 2017
PDF Full-text (1609 KB)
Abstract
To study drug response on human heart cells and predict drug induced cardiotoxicity, a microfluidic cell culture device with an integrated microelectrode array (MEA) is a promising approach. Here we integrate flexible MEA into microengineered and microfluidic in vitro human models, known as
[...] Read more.
To study drug response on human heart cells and predict drug induced cardiotoxicity, a microfluidic cell culture device with an integrated microelectrode array (MEA) is a promising approach. Here we integrate flexible MEA into microengineered and microfluidic in vitro human models, known as “Body-on-a-Chip”, during its fabrication. In this work, Au electrodes are covered by two layers of parylene C films, and then embedded in a polydimethylsiloxane (PDMS) layer, resulting in an easy-to-integrate process and compatible with soft-lithography. For a proof of fabrication concept, the impedance of individual electrode-electrolyte interfaces are measured to show a potential for network electrophysiology. Full article
Open AccessProceedings Cu Thin Film Polyimide Heater for Nerve-Net Tactile Sensor
Proceedings 2017, 1(4), 303; doi:10.3390/proceedings1040303
Published: 11 August 2017
PDF Full-text (1432 KB)
Abstract
Tactile sensing is required for assistant robots. A new stacked sensor head was proposed which detects forces and thermal sensations with a nerve-net LSI chip. To measure temperatures and heat flows, the sensor head required a thin and small heater to heat up
[...] Read more.
Tactile sensing is required for assistant robots. A new stacked sensor head was proposed which detects forces and thermal sensations with a nerve-net LSI chip. To measure temperatures and heat flows, the sensor head required a thin and small heater to heat up the sensor head. The features of the polyimide heater are compact, low heat capacity, low power consumption and ease of attaching it to the LSI chip. The polyimide heater consisted of Au 10 nm/Cu 200 nm/Cr 20 nm thickness layers on a polyimide film. The surface of the sensor head heated up to 60 °C by the polyimide heater with 0.3 W. By the Cu thin film polyimide heater, the small stacked sensor head with the nerve-net LSI chip is enable to detect forces, temperatures, and heat flows, simultaneously. Full article
Open AccessProceedings Fabrication of Sharp Tip-Separable Microneedle Device for Trans-Dermal Drug Delivery Systems
Proceedings 2017, 1(4), 304; doi:10.3390/proceedings1040304
Published: 17 August 2017
PDF Full-text (1392 KB)
Abstract
An alignment mechanism for producing a sharp tip-separable microneedle device for trans-dermal drug delivery systems has been developed. The needle and base parts were placed on a mechanical precision motion stage to align their central axes. The overlapping region between them in the
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An alignment mechanism for producing a sharp tip-separable microneedle device for trans-dermal drug delivery systems has been developed. The needle and base parts were placed on a mechanical precision motion stage to align their central axes. The overlapping region between them in the height direction was controlled by inserting a thickness gauge between them. A 400-μm-high sharp tip-separable microneedle device was successfully produced by using the developed alignment mechanism with an accuracy of less than 19 μm. We also demonstrated that it can be used to produce an arrayed tip-separable microneedle device. Full article
Open AccessProceedings Scandium Aluminium Nitride-Based Film Bulk Acoustic Resonators
Proceedings 2017, 1(4), 305; doi:10.3390/proceedings1040305
Published: 18 August 2017
PDF Full-text (309 KB)
Abstract
Film bulk acoustic resonators (FBAR) are promising candidates to replace surface acoustic wave devices as filters or delay lines, but also offer exciting opportunities as biological or gas sensors. In this work, solidly mounted FBARs were manufactured by substituting commonly used pure aluminium
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Film bulk acoustic resonators (FBAR) are promising candidates to replace surface acoustic wave devices as filters or delay lines, but also offer exciting opportunities as biological or gas sensors. In this work, solidly mounted FBARs were manufactured by substituting commonly used pure aluminium nitride (AlN) by scandium doped aluminium nitride (ScAlN) thin films as the piezoelectric layer. The ScAlN-based resonators feature a significant improvement of the electromechanical coupling factor from ~3% to ~12% compared to the pure AlN, while the decreased stiffness of ScAlN results in a decrease of the quality factor from ~300 to ~100 due to increased damping losses in the piezoelectric material. Full article
Open AccessProceedings Segmented Control of Electrostatically Actuated Bimorph Beams
Proceedings 2017, 1(4), 306; doi:10.3390/proceedings1040306
Published: 25 August 2017
PDF Full-text (523 KB)
Abstract
This research focused on improving the control and sensing of electrostatically actuated, large deflection bimorph beams for optical beam steering. Current iterations of designs utilize a ‘zipper’ beam and have demonstrated large deflection angles. However, with these devices precise control and deflection measurements
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This research focused on improving the control and sensing of electrostatically actuated, large deflection bimorph beams for optical beam steering. Current iterations of designs utilize a ‘zipper’ beam and have demonstrated large deflection angles. However, with these devices precise control and deflection measurements can be difficult to achieve. Through using segmented bias channels of doped polysilicon, modeling shows it is possible to control and measure different segments of the actuation arm, thus controlling the amount of tip, tilt, or piston deflection. This paper discusses current and future designs, along with test procedures and modeling results. Full article
Open AccessProceedings Novel Method for Adhesion between PI-PDMS Using Butyl Rubber for Large Area Flexible Body Patches
Proceedings 2017, 1(4), 307; doi:10.3390/proceedings1040307
Published: 7 August 2017
PDF Full-text (408 KB)
Abstract
This paper reports the use of rubber—Polybutadiene as an intermediate adhesive layer for improving the adhesion between polyimide (PI) and silicone polydimethylsiloxane (PDMS) which is required for a reliable fabrication of flexible/stretchable body patches for various applications. The adhesive bond initiated by the
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This paper reports the use of rubber—Polybutadiene as an intermediate adhesive layer for improving the adhesion between polyimide (PI) and silicone polydimethylsiloxane (PDMS) which is required for a reliable fabrication of flexible/stretchable body patches for various applications. The adhesive bond initiated by the butyl rubber (BR), apart from being extremely strong, is also chemically resistant and mechanically stable as compared to the state of the art processes of improving adhesion between PI and Silicone. Full article
Open AccessProceedings Incorporation of ZnO Nanostructures in MIS Architecture through Chemical Routes
Proceedings 2017, 1(4), 308; doi:10.3390/proceedings1040308
Published: 18 August 2017
PDF Full-text (926 KB)
Abstract
Because it’s physical properties, ZnO is considered a potential semiconductor compound for fabricating electronic and optoelectronic functional devices. In this regard, several growth techniques have been developed in order to meet the requirements of commercial devices based in this material. On the pathway
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Because it’s physical properties, ZnO is considered a potential semiconductor compound for fabricating electronic and optoelectronic functional devices. In this regard, several growth techniques have been developed in order to meet the requirements of commercial devices based in this material. On the pathway for improving the performance of the current devices, low-dimensional ZnO structures seem a promising alternative. Here, we report the process to obtain a metal-insulator-semiconductor (MIS) structure based on ZnO nanostructures grown on the surface of an anodized aluminum substrate (Al2O3/Al) by chemical routes. Full article
Open AccessProceedings Nanofabrication of Vertically Aligned 3D GaN Nanowire Arrays with Sub-50 nm Feature Sizes Using Nanosphere Lift-off Lithography
Proceedings 2017, 1(4), 309; doi:10.3390/proceedings1040309
Published: 8 August 2017
PDF Full-text (583 KB)
Abstract
Vertically aligned 3D gallium nitride (GaN) nanowire arrays with sub-50 nm feature sizes were fabricated using a nanosphere lift-off lithography (NSLL) technique combined with hybrid top-down etching steps (i.e., inductively coupled plasma dry reactive ion etching (ICP-DRIE) and wet chemical etching). Owing to
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Vertically aligned 3D gallium nitride (GaN) nanowire arrays with sub-50 nm feature sizes were fabricated using a nanosphere lift-off lithography (NSLL) technique combined with hybrid top-down etching steps (i.e., inductively coupled plasma dry reactive ion etching (ICP-DRIE) and wet chemical etching). Owing to the well-controlled chemical surface treatment prior to the nanobead deposition and etching process, vertical GaN nanowire arrays with diameter of ~35 nm, pitch of ~350 nm, and aspect ratio of >10 could be realized using 500 nm polystyrene nanobead (PN) masks. This work has demonstrated a feasibility of using NSLL as an alternative for other sophisticated but expensive nanolithography methods to manufacture low-cost but highly ordered 3D GaN nanostructures. Full article
Open AccessProceedings Thermal Stability of Micro-Structured PDMS Piezo-Electrets under Various Polymeric Reticulation Ratios for Sensor Applications
Proceedings 2017, 1(4), 310; doi:10.3390/proceedings1040310
Published: 21 August 2017
PDF Full-text (451 KB)
Abstract
The effect of the polymeric reticulation on the thermal stability of the piezoelectricity of a micro-structured PDMS piezo-electret was investigated. This new family of flexible piezoelectric materials with very low Young’s modulus is used for wearable sensors and energy harvester devices. The best
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The effect of the polymeric reticulation on the thermal stability of the piezoelectricity of a micro-structured PDMS piezo-electret was investigated. This new family of flexible piezoelectric materials with very low Young’s modulus is used for wearable sensors and energy harvester devices. The best thermal stability was obtained for the piezo-electret material made from the ratio 1:10 between the prepolymer and the crosslinking agent with a longitudinal piezoelectric coefficient d33 = 350 pC/N. The highest piezoelectric coefficient d33 = 750 pC/N was obtained for the ratio 1:20, but the piezoelectricity was lost at 45 °C by thermally stimulated discharge Full article
Open AccessProceedings Thermoelectric Measurement of a Single, TiO2-Catalyzed Bi2Te3 Nanowire
Proceedings 2017, 1(4), 311; doi:10.3390/proceedings1040311
Published: 24 August 2017
PDF Full-text (691 KB)
Abstract
We report on the functionality of our Thermoelectric Nanowire Characterization Platform (TNCP). As a proof of concept of our design, we present a set of experimental results obtained from the characterization of a single Bi2Te3 nanowire, allowing for the determination
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We report on the functionality of our Thermoelectric Nanowire Characterization Platform (TNCP). As a proof of concept of our design, we present a set of experimental results obtained from the characterization of a single Bi2Te3 nanowire, allowing for the determination of the nanowire’s electrical conductivity and Seebeck coefficient. Full article
Open AccessProceedings On the Development of Label-Free DNA Sensor Using Silicon Nanonet Field-Effect Transistors
Proceedings 2017, 1(4), 312; doi:10.3390/proceedings1040312
Published: 28 August 2017
PDF Full-text (762 KB)
Abstract
In this paper, the process and electrical characteristics of DNA sensor devices based on silicon nanonet (SiNN) field-effect transistors are reported. The SiNN, another name of randomly oriented Si nanowires network, was successfully integrated into transistor as p-type channel using standard microelectronic technology.
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In this paper, the process and electrical characteristics of DNA sensor devices based on silicon nanonet (SiNN) field-effect transistors are reported. The SiNN, another name of randomly oriented Si nanowires network, was successfully integrated into transistor as p-type channel using standard microelectronic technology. The SiNN-based transistors exhibit a high initial ON-state current (5.10−8 A) and homogeneous electrical characteristics. For DNA detection, a new and eco-friendly functionalization process based on glycidyloxypropyltrimethoxysilane (GOPS) was performed which enables the covalent grafting of DNA probes on SiNN. This hybridization leads to a significant decrease of ON-state current of device. Additionally, it is observed that SiNN devices reveal reproductive current response to DNA detection. We demonstrate, for the first time, the successful integration of SiNN into sensor for electrical label-free DNA detection at low cost. Full article
Open AccessProceedings Particle Separation with Deterministic Lateral Displacement (DLD): The Anisotropy Effect
Proceedings 2017, 1(4), 313; doi:10.3390/proceedings1040313
Published: 18 August 2017
PDF Full-text (1756 KB)
Abstract
Deterministic lateral displacement (DLD) is a passive and label-free microfluidic separation technique with a strong potential for biological sample preparation purposes. Numerical and experimental models have been proposed so far to predict the particle behavior in DLD channels. However, they do not take
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Deterministic lateral displacement (DLD) is a passive and label-free microfluidic separation technique with a strong potential for biological sample preparation purposes. Numerical and experimental models have been proposed so far to predict the particle behavior in DLD channels. However, they do not take into account the influence of the pillar anisotropy that induces a secondary pressure gradient in the direction perpendicular to the main flow. The influence of the pillar geometry on the anisotropy magnitude is presented. We show that anisotropy impacts the trajectory of particles in DLD devices and should be included in predictive models for the critical diameter. Full article
Open AccessProceedings Ionogel—Based Composite Material for CO2 Sensing Deposited on a Chemiresistive Transducer
Proceedings 2017, 1(4), 314; doi:10.3390/proceedings1040314
Published: 17 August 2016
PDF Full-text (1009 KB)
Abstract
A novel miniaturized carbon dioxide (CO2) sensor based on an IDE transducer is described and characterized. The CO2 sensor based on different semiconducting metal oxide and ionogel composites films deposited by ink-jet printing. The sensor is operated as a simple
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A novel miniaturized carbon dioxide (CO2) sensor based on an IDE transducer is described and characterized. The CO2 sensor based on different semiconducting metal oxide and ionogel composites films deposited by ink-jet printing. The sensor is operated as a simple chemiresistor. The sensors were investigated under trace gas exposure (CO2, NO2, CO and humidity). The CO2 sensitivity is found to be exceptionally high and the sensing mechanism is supposed to be entirely different compared to those of the components of the composite. Full article
Open AccessProceedings Protuberant Electrode Structures for New Retinal Implants
Proceedings 2017, 1(4), 315; doi:10.3390/proceedings1040315
Published: 9 August 2017
PDF Full-text (608 KB)
Abstract
Focal stimulation of neural tissue is a challenge in retinal prosthetic devices in which the aim is to improve the spatial resolution of the stimulation and therefore increase the electrode density of the prosthetic devices. Our work intends to create a new implant
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Focal stimulation of neural tissue is a challenge in retinal prosthetic devices in which the aim is to improve the spatial resolution of the stimulation and therefore increase the electrode density of the prosthetic devices. Our work intends to create a new implant able to enhance the focalisation of the stimulation signal through protuberant electrodes. These electrodes are micro fabricated on a soft polyimide substrate using classical metal electrodeposition techniques. Before proceeding with fabrication a FEM model of the electrode’s current density was done to select the best-performing structures and geometries in terms of local stimulation. Based on these models, several prototypes were fabricated and implanted in vivo into a rat’s eye to verify the adaptation to the retina tissue. Full article
Open AccessProceedings Aerosol Jet Printing of Miniaturized, Low Power Flexible Micro-Hotplates
Proceedings 2017, 1(4), 316; doi:10.3390/proceedings1040316
Published: 17 August 2017
PDF Full-text (814 KB)
Abstract
We report on printed flexible micro-hotplates operating at high temperature at lower power consμmption than ever reported using aerosol jet printing of fine metallic conductor features. Efficient heating (i.e., 40 mW at 325 °C) was produced by reducing the effective heating area and
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We report on printed flexible micro-hotplates operating at high temperature at lower power consμmption than ever reported using aerosol jet printing of fine metallic conductor features. Efficient heating (i.e., 40 mW at 325 °C) was produced by reducing the effective heating area and substrates thickness. Gold (Au) nanoparticles solution was used for printing micro-hotplates of two different sizes, i.e., 500 × 500 μm2 and 300 × 300 μm2, on 50 μm- and 13 μm-thick PI substrates, respectively. Comsol simulations were used to optimize the thermal design of micro-hotplates. Their power consμmption at 325 °C was of 54 mW for the large hotplate and of 40 mW for the smaller design. These results validate the simple manufacturing of high temperature and power efficient flexible micro-hotplates for applications such as in portable gas and chemical sensors, thermal metrology, etc. Full article
Open AccessProceedings Repeated Temperature and Humidity Stability of SERS-active Periodical Silver Nanostructure
Proceedings 2017, 1(4), 317; doi:10.3390/proceedings1040317
Published: 8 August 2017
PDF Full-text (479 KB)
Abstract
In this work the effect of physical aging on the plasmonic properties of surface plasmon-polariton supported silver grating was studied. As physical treatment the periodical variation of external temperature, humidity and their combination was applied. It was previously expected, that the physical aging
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In this work the effect of physical aging on the plasmonic properties of surface plasmon-polariton supported silver grating was studied. As physical treatment the periodical variation of external temperature, humidity and their combination was applied. It was previously expected, that the physical aging will results in the silver oxidation, redistribution, and potential worse of plasmonic properties. The oxidation processes were studied using the XPS technique, the changes of surface morphology were examined by AFM, and finally, the shift of plasmonic efficiency was checked using the SERS test. Full article
Open AccessProceedings Layer by Layer Deposition of Colloidal SnO2 Nano Particles
Proceedings 2017, 1(4), 318; doi:10.3390/proceedings1040318
Published: 22 August 2017
PDF Full-text (2076 KB)
Abstract
The gas sensing properties of functional metal oxide layers depend on multitude parameters, including vacancy concentration, layer morphology and thickness, size and shape of the nano/microstructure, and porosity. Using colloidal tin oxide inks we demonstrate a layer by layer deposition technique to control
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The gas sensing properties of functional metal oxide layers depend on multitude parameters, including vacancy concentration, layer morphology and thickness, size and shape of the nano/microstructure, and porosity. Using colloidal tin oxide inks we demonstrate a layer by layer deposition technique to control the thickness and composition of gas sensitive layers. To do this we combine inkjet-printing with colloidal suspensions of SnO2 particles to provide a scalable method to interface microelectromechanical systems (MEMS) with nano particles. The approach may pave the way towards an industry ready integration technique to incorporate gas sensitive quantum dots or hybrid nanomaterials in arbitrary sensing devices. Full article
Open AccessProceedings Near Infrared Plasmonic Gas Sensing with Doped Metal Oxide Nanocrystals
Proceedings 2017, 1(4), 319; doi:10.3390/proceedings1040319
Published: 5 September 2017
PDF Full-text (265 KB)
Abstract
In this paper, we demonstrate the application of ZnO doped with gallium (GZO), aluminum (AZO) and germanium (GeZO) nanocrystals as novel plasmonic and chemiresistive sensors for the detection of hazardous gases including hydrogen (H2) and nitrogen dioxide (NO2). GZO,
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In this paper, we demonstrate the application of ZnO doped with gallium (GZO), aluminum (AZO) and germanium (GeZO) nanocrystals as novel plasmonic and chemiresistive sensors for the detection of hazardous gases including hydrogen (H2) and nitrogen dioxide (NO2). GZO, AZO and GeZO nanocrystals are obtained by non-aqueous colloidal heat-up synthesis with high transparency in the visible range and strong localized surface plasmon resonance (LSPR) in the near IR range, tunable with dopant concentration (up to 20% mol nominal). Thanks to the strong sensitivity of the LSPR to chemical and electrical changes occurring at the surface of the nanocrystals, such optical features can be used to detect the presence of toxic gases. By monitoring the changes in the dopant-induced plasmon resonance in the near infrared, we demonstrate that GZO, AZO and GeZO thin films prepared depositing an assembly of highly doped ZnO colloids are able to optically detect both oxidizing and reducing gases at mild (<100 °C) operating temperatures. Combined optical and electrical measurements show that the dopants within ZnO nanocrystals enhance the gas sensing response compared to undoped ZnO. Full article
Open AccessProceedings Optical and Morphological Analysis of c-Si/PSi and c-Si/PSi/MWCNT/SiOx Heterostructures
Proceedings 2017, 1(4), 320; doi:10.3390/proceedings1040320
Published: 9 August 2017
PDF Full-text (735 KB)
Abstract
In the present work, the optical and morphological properties of Porous Silicon (PSi) in the c-Si-n/PSi and c-Si-n/SiP-n/MWCNT/SiOx structures are studied and analyzed. The PSi layer is grown on n-type c-Si (<0.005 Ω·cm <100>) by electrochemical anodization using different currents as: 10,
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In the present work, the optical and morphological properties of Porous Silicon (PSi) in the c-Si-n/PSi and c-Si-n/SiP-n/MWCNT/SiOx structures are studied and analyzed. The PSi layer is grown on n-type c-Si (<0.005 Ω·cm <100>) by electrochemical anodization using different currents as: 10, 50 and 100 mA. The etching solution used was C2H6O:HF:C3H8O3 in a proportion of 6:3:1 by volume, respectively. The deposition of multi wall carbon nanotubes (MWNTs) on the PSi was done by spin coating, and later the surface was passivated by thermal oxidation. The porosity and thickness were obtained by gravimetry. UV-VIS spectroscopy and photoluminescence were used to obtain the optical properties and SEM was used to analyze the morphology. Full article
Open AccessProceedings Gas Sensors Based on Individual (Ga, In)2O3 Nanowires
Proceedings 2017, 1(4), 321; doi:10.3390/proceedings1040321
Published: 21 August 2017
PDF Full-text (629 KB)
Abstract
In this work the growth and characterisation of (Ga, In)2O3 NWs inside a CVD furnace using different mixtures of Ga2O3 and In2O3 is reported. The NWs have been characterised by SEM, XRD and TEM,
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In this work the growth and characterisation of (Ga, In)2O3 NWs inside a CVD furnace using different mixtures of Ga2O3 and In2O3 is reported. The NWs have been characterised by SEM, XRD and TEM, proving their cubic crystalline nature similar to In2O3 and the degree of incorporation of Ga in this lattice. Furthermore, gas nanosensors based on single NWs have been fabricated and measured, demonstrating the sensing properties of the synthesized material. Full article
Open AccessProceedings Eni Carbon Silicates: Innovative Hybrid Materials for Room-Temperature Gas Sensing
Proceedings 2017, 1(4), 322; doi:10.3390/proceedings1040322
Published: 30 August 2017
PDF Full-text (594 KB)
Abstract
The purpose of this work was to satisfy both materials and technological sciences, on the one hand implementing innovative hybrid materials referred to as ECS (Eni Carbon Silicate) in gas sensors manufacturing, and on the other hand verifying their possible operation at room
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The purpose of this work was to satisfy both materials and technological sciences, on the one hand implementing innovative hybrid materials referred to as ECS (Eni Carbon Silicate) in gas sensors manufacturing, and on the other hand verifying their possible operation at room temperature as a technological progress. The ECS-14 and ECS-13 phases were employed as functional materials for films deposited by drop coating onto alumina substrates. Room-temperature gas tests were performed to study their potential sensing properties. In humidity conditions, the ECS-14 based sensor showed outstanding performance and a complete calibration vs. moisture concentration was obtained. Full article
Open AccessProceedings Laser Interferometry for Broad Area SPR-Grating Couplers in Chemical Applications
Proceedings 2017, 1(4), 323; doi:10.3390/proceedings1040323
Published: 28 August 2017
PDF Full-text (1084 KB)
Abstract
In this work, the fabrication of a SPR (Surface Plasmon Resonance)-grating coupler using Laser Interference Lithography (LIL) has been investigated, giving rise to large area diffraction gratings on a 100 nm-thick gold film. The period of the diffraction grating is Λ = 500
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In this work, the fabrication of a SPR (Surface Plasmon Resonance)-grating coupler using Laser Interference Lithography (LIL) has been investigated, giving rise to large area diffraction gratings on a 100 nm-thick gold film. The period of the diffraction grating is Λ = 500 nm. The SPR sensor has been tested towards several liquids showing a maximum sensitivity of S = 390 nm/RIU. Full article
Open AccessProceedings MEMS Sensors Based on Very Thin LTCC
Proceedings 2017, 1(4), 324; doi:10.3390/proceedings1040324
Published: 16 August 2017
PDF Full-text (893 KB)
Abstract
The application of thin LTCC is a very interesting and promising approach to the fabrication of ceramic MEMS gas sensors. The attempts to use this material were restricted till now by the thickness of commercial material (>50 μm). In this work, we found
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The application of thin LTCC is a very interesting and promising approach to the fabrication of ceramic MEMS gas sensors. The attempts to use this material were restricted till now by the thickness of commercial material (>50 μm). In this work, we found a possibility to fabricate thin LTCC membranes (20–30 μm) stretched on a frame made of 100 μm thick LTCC. Aerosol jet printed Pt microheater and laser cutting of the membrane gave a cantilever shaped microhotplate with hot spot of about 300 × 300 μm. Power consumption of the heater is ~150 mW at 450 °C. Full article
Open AccessProceedings DNA-Origami-Aided Lithography for Sub-10 Nanometer Pattern Printing
Proceedings 2017, 1(4), 325; doi:10.3390/proceedings1040325
Published: 8 August 2017
PDF Full-text (556 KB)
Abstract
We report the first DNA-based origami technique that can print addressable patterns on surfaces with sub-10 nm resolution. Specifically, we have used a two-dimensional DNA origami as a template (DNA origami stamp) to transfer DNA with pre-programmed patterns (DNA ink) on gold surfaces.
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We report the first DNA-based origami technique that can print addressable patterns on surfaces with sub-10 nm resolution. Specifically, we have used a two-dimensional DNA origami as a template (DNA origami stamp) to transfer DNA with pre-programmed patterns (DNA ink) on gold surfaces. The DNA ink is composed of thiol-modified staple strands incorporated at specific positions of the DNA origami stamp to create patterns upon thiol-gold bond formation on the surface (DNA ink). The DNA pattern formed is composed of unique oligonucleotide sequences, each of which is individually addressable. As a proof-of-concept, we created a linear pattern of oligonucleotide-modified gold nanoparticles complementary to the DNA ink pattern. We have developed an in silico model to identify key elements in the formation of our DNA origami-driven lithography and nanoparticle patterning as well as simulate more complex nanoparticle patterns on surfaces. Full article
Open AccessProceedings Fabrication of Hybrid Microfluidic System on Transparent Substrates for Electrochemical Applications
Proceedings 2017, 1(4), 326; doi:10.3390/proceedings1040326
Published: 8 August 2017
PDF Full-text (411 KB)
Abstract
In this work the critical aspects of the process sequence developed for fabrication of hybrid polymer microfluidic systems integrating metal electrode pattern and precisely aligned microfluidic structure are discussed in details. Glass and polycarbonate were considered as primary transparent substrate materials for metal
[...] Read more.
In this work the critical aspects of the process sequence developed for fabrication of hybrid polymer microfluidic systems integrating metal electrode pattern and precisely aligned microfluidic structure are discussed in details. Glass and polycarbonate were considered as primary transparent substrate materials for metal (Au, Pt) electrode deposition and the microchannels were formed in multi-layered SU-8 negative photoresist. Poly(dimethylsiloxane) (PDMS) layer was proposed as cover layer to ensure proper sealing and sample inlet formation. Full article
Open AccessProceedings Characterization and Ammonia Sensing Properties of 2D SnS2/SnO2−x Flakes-Based Films
Proceedings 2017, 1(4), 327; doi:10.3390/proceedings1040327
Published: 9 August 2017
PDF Full-text (358 KB)
Abstract
Hybrid SnS2-SnO2−x flaked nanostructures were obtained from 2D-SnS2 flakes deposited as a thin sensing film onto a conductometric transducing platform and annealed in air. The formation of 2D-SnS2/SnO2−x mixed phases and the materials morphologies were investigated
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Hybrid SnS2-SnO2−x flaked nanostructures were obtained from 2D-SnS2 flakes deposited as a thin sensing film onto a conductometric transducing platform and annealed in air. The formation of 2D-SnS2/SnO2−x mixed phases and the materials morphologies were investigated by in situ Micro-Raman spectroscopy and SEM-EDX analysis. As annealing temperature of the sensitive film increases, the response towards ammonia increases showing a maximum at 250 °C. This behavior can be explained on the basis of the morphological modification and the formation of mixed phases. Full article
Open AccessProceedings Fabrication Tolerance Sensitivity in Large-Area Mid-Infrared Metamaterial Absorbers
Proceedings 2017, 1(4), 328; doi:10.3390/proceedings1040328
Published: 8 August 2017
PDF Full-text (826 KB)
Abstract
Metamaterial absorbers are photonic structures composed of an array of sub-wavelength metallic patterns. Results in literature are usually based on structures of nominal dimensions, despite the significant effect of fabrication tolerances on performance. This research aims to identify the main sources of uncertainty
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Metamaterial absorbers are photonic structures composed of an array of sub-wavelength metallic patterns. Results in literature are usually based on structures of nominal dimensions, despite the significant effect of fabrication tolerances on performance. This research aims to identify the main sources of uncertainty and to investigate their effect, notably that of an irregular surface quality (i.e., roughness) of the thin metallic layer and the lithography related variations in size and shape. The effect of the shape and positioning of the resonance peak was investigated and validated using mid-infrared metamaterial absorbers. This sensitivity analysis is essential to the batch fabrication of metamaterial absorbers for MEMS applications. Full article
Open AccessProceedings A Novell Hall Magnetometer Using Dynamic Offset Cancellation
Proceedings 2017, 1(4), 329; doi:10.3390/proceedings1040329
Published: 9 August 2017
PDF Full-text (267 KB)
Abstract
A novel Hall magnetometer using dynamic offset cancellation principle is presented. It consists from a single triangular silicon plate with three contacts and interface electronics. The proposed dynamic offset-cancelling measurement cycle includes three states. During each state, an external circuit is switched to
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A novel Hall magnetometer using dynamic offset cancellation principle is presented. It consists from a single triangular silicon plate with three contacts and interface electronics. The proposed dynamic offset-cancelling measurement cycle includes three states. During each state, an external circuit is switched to the plate contacts in a certain way. This way, the direction of current flow through the Hall plate is changed from phase to phase. At the same time, the output voltage is measured. After averaging the obtained three voltages per a measurement cycle, the offset voltage cancelled and this way the offset-free Hall voltage is obtained. The obtained offset reduction factor is very promising, reaching 120–130. The Hall device sensitivity is about 25 V/AT. Full article
Open AccessProceedings Angle Measurement and 3D Magnetic Field Sensing Using Circular Hall Microsensor
Proceedings 2017, 1(4), 330; doi:10.3390/proceedings1040330
Published: 8 August 2017
PDF Full-text (640 KB)
Abstract
A new three-axis magnetometer for both 3-D magnetic field sensing and contactless in-plane 360° absolute angle encoding has been developed. The magnetometer is based on the Hall effect and consists of a circular in-plane sensitive CMOS Hall-effect microsensor, biasing and signal conditioning circuits.
[...] Read more.
A new three-axis magnetometer for both 3-D magnetic field sensing and contactless in-plane 360° absolute angle encoding has been developed. The magnetometer is based on the Hall effect and consists of a circular in-plane sensitive CMOS Hall-effect microsensor, biasing and signal conditioning circuits. The sensing device contains a narrow n-well ring with a chain of contacts positioned radial on the ring. The signal conditioning circuit gives two output analogue signals: a voltage Vz, proportional to the magnetic field component Bz, and a sine wave function Vxy(t). The magnitude of the in-plane magnetic field B(x,y) is directly proportional to the sine amplitude and the phase Ψ corresponds to the angle between the applied in-plane magnetic field and a reference direction. Full article
Open AccessProceedings Monitoring the Etching Process in LPFGs towards Development of Highly Sensitive Sensors
Proceedings 2017, 1(4), 331; doi:10.3390/proceedings1040331
Published: 11 August 2017
Cited by 1 | PDF Full-text (821 KB)
Abstract
In this work, the monitoring of the etching process up to a diameter of 30 µm of two LPFG structures has been compared, one of them had initially 125 µm, whereas the second one had 80 µm. By tracking the wavelength shift of
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In this work, the monitoring of the etching process up to a diameter of 30 µm of two LPFG structures has been compared, one of them had initially 125 µm, whereas the second one had 80 µm. By tracking the wavelength shift of the resonance bands during the etching process it is possible to check the quality of etching process (the 80 µm fibre performs better than de 125 µm fibre), and to stop for a specific cladding mode coupling, which permits to obtain an improved sensitivity compared to the initial structure. Full article
Open AccessProceedings Absorption Based Characterization Method for Fluid Properties Using Electrowetting-on-Dielectric Forces: Modeling and Fabrication
Proceedings 2017, 1(4), 332; doi:10.3390/proceedings1040332
Published: 11 August 2017
PDF Full-text (804 KB)
Abstract
Electrowetting-on-Dielectrics (EWOD) can be used to build a device, where a polar fluid droplet gets actuated between two EWOD electrodes. In our setup, each electrode is located between a laser diode and an oppositely arranged photo diode. In that manner, the presence of
[...] Read more.
Electrowetting-on-Dielectrics (EWOD) can be used to build a device, where a polar fluid droplet gets actuated between two EWOD electrodes. In our setup, each electrode is located between a laser diode and an oppositely arranged photo diode. In that manner, the presence of a fluid droplet located above one certain electrode can be optically detected by means of this transmission setup. The droplet’s viscosity dependent switching time, i.e., the time it takes to move the droplet between these two electrodes can be obtained by a time difference measurement of both transmission signals. CFD simulations of the switching time, which depends on the droplet’s viscosity, and furthermore absorption simulations according to the Beer Lambert law have been carried out with DI water as a sample fluid. A low-cost and rapid fabrication method of the so called absorption EWOD (aEWOD) switch is reported and the fabricated EWOD stack is characterized with the aid of surface profilometry. Full article
Open AccessProceedings Etched and Nanocoated SMS Fiber Sensor for Detection of Salinity Concentration
Proceedings 2017, 1(4), 333; doi:10.3390/proceedings1040333
Published: 25 August 2017
PDF Full-text (857 KB)
Abstract
An optical fibre refractometer has been developed by etching and deposition of a thin film of indium tin oxide (ITO) on a single-mode-multimode-single-mode (SMS) fibre structure. The interference between modes in this structure is sensitive to the refractive index changes of the surrounding
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An optical fibre refractometer has been developed by etching and deposition of a thin film of indium tin oxide (ITO) on a single-mode-multimode-single-mode (SMS) fibre structure. The interference between modes in this structure is sensitive to the refractive index changes of the surrounding medium, achieving sensitivities of up to 7000 nm/RIU in the 1.333–1.338 RIU range. A salinity sensor has been implemented as a practical application of this proposed structure. Fast Fourier transform (FFT) analysis and tracking of an interference dip were used to monitor the interference between modes obtaining sensitivities of 0.99 nm/PSU and 0.025 rad/PSU, respectively. Full article
Open AccessProceedings Low-Power Heating Platform for the Characterization and Calibration of Scanning Thermal Probes
Proceedings 2017, 1(4), 334; doi:10.3390/proceedings1040334
Published: 25 August 2017
PDF Full-text (1283 KB)
Abstract
We report on a micro-hotplate technology platform optimized for the calibration of Scanning Thermal Microscopy probes (SThM) used in surface temperature measurement mode. The three chips designed include the same heating area with a calibration area of 10 × 10 µm2 where
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We report on a micro-hotplate technology platform optimized for the calibration of Scanning Thermal Microscopy probes (SThM) used in surface temperature measurement mode. The three chips designed include the same heating area with a calibration area of 10 × 10 µm2 where the SThM probes can land. The 1st design allows to study the influence of the nature of the material on the SThM probes thermal contact resistance. The 2nd design includes a resistive temperature sensor (RTD) integrated on the contact area, which is dedicated to evaluate the capability of a probe to measure a surface temperature. The 3rd design has a contact area made of a suspended platinum membrane for coupling SThM probes with optical thermal measurements. The thermal response of a thermocouple (TC) SThM probe was extracted demonstrating the relevance of these chips for SThM probes characterization and calibration. Full article
Open AccessProceedings Direct Piezoelectric Coefficient Measurements of PVDF and PLLA under Controlled Strain and Stress
Proceedings 2017, 1(4), 335; doi:10.3390/proceedings1040335
Published: 16 August 2017
PDF Full-text (799 KB)
Abstract
Open-circuit direct piezoelectric coefficients g31 of bi-axially stretched PVDF and chiral PLLA are reported. This measure is decisive for sensor, generator and energy harvesting applications. We use an in-situ method with contactless voltage measurement during a conventional tensile-test, greatly improving measurement precision
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Open-circuit direct piezoelectric coefficients g31 of bi-axially stretched PVDF and chiral PLLA are reported. This measure is decisive for sensor, generator and energy harvesting applications. We use an in-situ method with contactless voltage measurement during a conventional tensile-test, greatly improving measurement precision (error less than 10%). Full article
Open AccessProceedings Transparent Glass/SU8-Based Microfluidic Device with on-Channel Electrical Sensors
Proceedings 2017, 1(4), 336; doi:10.3390/proceedings1040336
Published: 17 August 2017
PDF Full-text (735 KB)
Abstract
This paper presents a transparent microfluidic chip designed for continuous-flow photochemistry applications with integrated electrical sensing. The transparent chip design allows for microscale photochemistry, and permits direct, real-time visual/electrical observation. The microchip uses optically transparent indium tin oxide (ITO) electrodes for reagent and
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This paper presents a transparent microfluidic chip designed for continuous-flow photochemistry applications with integrated electrical sensing. The transparent chip design allows for microscale photochemistry, and permits direct, real-time visual/electrical observation. The microchip uses optically transparent indium tin oxide (ITO) electrodes for reagent and phase tracking. High-speed videography was performed to validate the electrical measurement data. Full article
Open AccessProceedings A Monolithic Three-Axis Accelerometer with Wafer-Level Package by CMOS MEMS Process
Proceedings 2017, 1(4), 337; doi:10.3390/proceedings1040337
Published: 11 August 2017
PDF Full-text (2146 KB)
Abstract
This paper presents a monolithic three-axis accelerometer with wafer-level package by CMOS MEMS process. The compositions of the microstructure are selected from CMOS layers in order to suppress the in-plane and out-of-plane bending deflection caused by the residual stresses in multiple layers. A
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This paper presents a monolithic three-axis accelerometer with wafer-level package by CMOS MEMS process. The compositions of the microstructure are selected from CMOS layers in order to suppress the in-plane and out-of-plane bending deflection caused by the residual stresses in multiple layers. A switched-capacitor sensing circuit with a trimming mechanism is used to amplify the capacitive signal, and decrease the output dc offset voltage to ensure the desired output voltage swing. The CMOS MEMS wafer is capped with a silicon wafer using a polymer-based material. The measured sensitivities with and without a wafer-level package range from 113 mV/G to 124 mV/G for the in-plane (x-axis, y-axis) accelerometer, and from 50 mV/G to 53 mV/G for the z-axis accelerometer, respectively. Full article
Open AccessProceedings Linear-Logarithmic CMOS Image Sensor with Reduced FPN Using Photogate and Cascode MOSFET
Proceedings 2017, 1(4), 338; doi:10.3390/proceedings1040338
Published: 18 August 2017
PDF Full-text (661 KB)
Abstract
We propose a linear-logarithmic CMOS image sensor with reduced fixed pattern noise (FPN). The proposed linear-logarithmic pixel based on a conventional 3-transistor active pixel sensor (APS) structure has additional circuits in which a photogate and a cascade MOSFET are integrated with the pixel
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We propose a linear-logarithmic CMOS image sensor with reduced fixed pattern noise (FPN). The proposed linear-logarithmic pixel based on a conventional 3-transistor active pixel sensor (APS) structure has additional circuits in which a photogate and a cascade MOSFET are integrated with the pixel structure in conjunction with the photodiode. To improve FPN, we applied the PMOSFET hard reset method as a reset transistor instead of NMOSFET reset normally used in APS. The proposed pixel has been designed and fabricated using 0.18-μm 1-poly 6-metal standard CMOS process. A 120 × 240 pixel array of test chip was divided into 2 different subsections with 60 × 240 sub-arrays, so that the proposed linear-logarithmic pixel with reduced FPN could be compared with the conventional linear-logarithmic pixel. We confirmed a reduction of pixel response variation which affected image quality. Full article
Open AccessProceedings Piezoresistive Pressure Sensors for Resin Flow Monitoring in Carbon Fibre-Reinforced Composite
Proceedings 2017, 1(4), 339; doi:10.3390/proceedings1040339
Published: 18 August 2017
PDF Full-text (279 KB)
Abstract
Using piezoresistive pressure sensors and in-situ measurement of pressure gradient, the infusion of resin in fiber reinforced composite can be optimized. The optimization of resin flow in Vacuum Assisted Resin Infusion (VARI) is necessary to produce high-quality fibre-reinforced composites. To control the resin
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Using piezoresistive pressure sensors and in-situ measurement of pressure gradient, the infusion of resin in fiber reinforced composite can be optimized. The optimization of resin flow in Vacuum Assisted Resin Infusion (VARI) is necessary to produce high-quality fibre-reinforced composites. To control the resin infusion process, piezoresistive pressure sensors are embedded to detect the resin flow and resin pressure in Carbon Fibre Reinforced Polymer (CFRP). The measured pressure validates the accuracy of analytical calculations, based on Darcy’s law in a porous medium. The sensors are of small size and therefore do not affect the natural flow of the resin. Full article
Open AccessProceedings A Combined Temperature and Stress Sensor in 0.18 μm CMOS Technology
Proceedings 2017, 1(4), 340; doi:10.3390/proceedings1040340
Published: 8 August 2017
PDF Full-text (676 KB)
Abstract
This paper presents a solution for on-chip temperature and mechanical stress measurement in CMOS integrated circuits. Thereby both temperature and stress sensors are realized as resistive Wheatstone bridges. By design, both sensors show outputs affected by non-linearities and parasitic cross-sensitivities. The novelty presented
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This paper presents a solution for on-chip temperature and mechanical stress measurement in CMOS integrated circuits. Thereby both temperature and stress sensors are realized as resistive Wheatstone bridges. By design, both sensors show outputs affected by non-linearities and parasitic cross-sensitivities. The novelty presented in this work is to combine both non-ideal sensor outputs by applying a two-dimensional Newton-Raphson method to extract the actual values of temperature and mechanical stress which were obtained with errors of less than 0.5 K and 0.5 MPa. Full article
Open AccessProceedings Harsh Environmental Surface Acoustic Wave Temperature Sensor Based on Pure and Scandium doped Aluminum Nitride on Sapphire
Proceedings 2017, 1(4), 341; doi:10.3390/proceedings1040341
Published: 17 August 2017
PDF Full-text (334 KB)
Abstract
This paper investigates the performance of surface acoustic wave (SAW) devices as low power MEMS temperature sensors using reactive sputter deposited aluminum nitride (AlN) and scandium doped aluminum nitride (AlScN) as piezoelectric layers on sapphire substrates. In detail, devices with a wavelength of
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This paper investigates the performance of surface acoustic wave (SAW) devices as low power MEMS temperature sensors using reactive sputter deposited aluminum nitride (AlN) and scandium doped aluminum nitride (AlScN) as piezoelectric layers on sapphire substrates. In detail, devices with a wavelength of 16 μm are fabricated with both AlN and AlScN films having a resonance frequency at room temperature of ~354 MHz and ~349 MHz, respectively. The samples are placed in a furnace and measured in argon atmosphere up to 800 °C. The temperature dependency on the frequency shows for both materials a linear decrease up to the maximum measured temperature level resulting in constant temperature coefficients of −27.62 kHz/°C and −27.81 kHz/°C, respectively. Full article
Open AccessProceedings MEMS Capacitive Microphone with Dual-Anchored Membrane
Proceedings 2017, 1(4), 342; doi:10.3390/proceedings1040342
Published: 9 August 2017
PDF Full-text (821 KB)
Abstract
In this paper, we proposed a MEMS capacitive microphone with a dual-anchored membrane. The proposed dual anchor could minimize the deviation of operating characteristics of the membrane according to the fabrication process variation. The membrane is connected and fixed to the back plate
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In this paper, we proposed a MEMS capacitive microphone with a dual-anchored membrane. The proposed dual anchor could minimize the deviation of operating characteristics of the membrane according to the fabrication process variation. The membrane is connected and fixed to the back plate insulating silicon nitride structures instead to the sacrificial bottom insulating oxide layer so that its effective size and boundary conditions are not changed according to the process variation. The proposed dual-anchored MEMS microphone is fabricated by the conventional fabrication process without no additional process and mask. It has a sensing membrane of 500 μm diameter, an air gap of 2.0 μm and 12 dual anchors of 15 μm diameter. The resonant frequency and the pull-in voltage of the fabricated device is 36.3 ± 1.3 kHz and 6.55 ± 0.20 V, respectively. Full article
Open AccessProceedings MEMS Inertial Switch for Military Applications
Proceedings 2017, 1(4), 343; doi:10.3390/proceedings1040343
Published: 9 August 2017
PDF Full-text (1053 KB)
Abstract
We developed a MEMS inertial switch (hereafter, the switch) for an ignition system of missiles. The developed switch consists of four folded beams and a plate suspended by the beams, analogous to a well-known spring-mass system. The plate and four beams compose a
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We developed a MEMS inertial switch (hereafter, the switch) for an ignition system of missiles. The developed switch consists of four folded beams and a plate suspended by the beams, analogous to a well-known spring-mass system. The plate and four beams compose a single body, which is made from single crystalline silicon wafers by deep reactive ion etching techniques. This process gives high thermal stability and stress-free structure. The switching, either open or close a conductive path, is achieved by the movement of the plate suspended with four folded beams when the acceleration exceeds a predetermined threshold. With a spinning-rate table, the function of the switch was tested at various revolution speeds. The test results are compared with the calculation results by our analytical model. Full article
Open AccessProceedings CMOS Technology Integrated Terahertz Rectifier
Proceedings 2017, 1(4), 344; doi:10.3390/proceedings1040344
Published: 22 August 2017
PDF Full-text (285 KB)
Abstract
We present new developments of CMOS compatible direct conversion terahertz detector operating at room temperature. The rectenna consists of an integrated antenna, realized on the surface of the integrated circuit and connected to a nanometric metallic whisker at one of its edges. The
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We present new developments of CMOS compatible direct conversion terahertz detector operating at room temperature. The rectenna consists of an integrated antenna, realized on the surface of the integrated circuit and connected to a nanometric metallic whisker at one of its edges. The rectifying device can be obtained introducing just minor modifications of the charge storage well in conventional CMOS active pixel image sensor devices, making the proposed solution easy to integrate with existing imaging systems. In the paper we present technological developments of the rectifier structure, realized with minor changes from a standard 0.15 µm technology node. We also present the study of a patch antenna which can be directly integrated on the chip. Full article
Open AccessProceedings Cricket Inspired High Efficiency MEMS Speakers
Proceedings 2017, 1(4), 345; doi:10.3390/proceedings1040345
Published: 18 August 2017
PDF Full-text (1804 KB)
Abstract
We report on the realization of a biomimetic MEMS speaker inspired by field crickets. This speaker is at least five times thinner and four times more efficient than the current dynamic speakers used in portable electronics. We present results of the acoustic characterization
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We report on the realization of a biomimetic MEMS speaker inspired by field crickets. This speaker is at least five times thinner and four times more efficient than the current dynamic speakers used in portable electronics. We present results of the acoustic characterization of a single MEMS speaker. Computational extrapolation of the results suggests that an array of such thin speakers will be highly efficient compared to the existing speakers of equal area. Full article
Open AccessProceedings A Comb-Based Capacitive MEMS Microphone with High Signal-to-Noise Ratio: Modeling and Noise-Level Analysis
Proceedings 2017, 1(4), 346; doi:10.3390/proceedings1040346
Published: 8 August 2017
PDF Full-text (1747 KB)
Abstract
We present a physics-based system-level model for optimizing a novel comb-based capacitive MEMS microphone towards high signal-to-noise ratios. The model includes non-linear coupling effects between the electrodes as well as the physical dependencies on relevant design parameters, thus enabling predictive statements w.r.t. the
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We present a physics-based system-level model for optimizing a novel comb-based capacitive MEMS microphone towards high signal-to-noise ratios. The model includes non-linear coupling effects between the electrodes as well as the physical dependencies on relevant design parameters, thus enabling predictive statements w.r.t. the device performance. It is calibrated and validated by finite element simulations and laser Doppler vibrometer measurements of first prototypes. Being formulated as a generalized Kirchhoffian network, it can be implemented in a standard circuit simulation tool. The predicted signal-to-noise ratio of this concept reaches up to 78 dB(A), which significantly exceeds state-of-the-art devices. Full article
Open AccessProceedings 1 Million-Q Optomechanical Microdisk Resonators with Very Large Scale Integration
Proceedings 2017, 1(4), 347; doi:10.3390/proceedings1040347
Published: 28 August 2017
PDF Full-text (693 KB)
Abstract
Cavity optomechanics have become a promising route towards the development of ultrasensitive sensors for a wide range of applications including mass, chemical and biological sensing. We demonstrate the potential of Very Large Scale Integration (VLSI) with state-of-the-art low-loss performance silicon optomechanical microdisks for
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Cavity optomechanics have become a promising route towards the development of ultrasensitive sensors for a wide range of applications including mass, chemical and biological sensing. We demonstrate the potential of Very Large Scale Integration (VLSI) with state-of-the-art low-loss performance silicon optomechanical microdisks for real-world applications. We report microdisks exhibiting optical Whispering Gallery Modes (WGM) with 1 million quality factors. These high-Q microdisks allow their Brownian motion to be resolved at few 100 MHz in ambient air. Such performance shows our VLSI process is a viable approach for the next generation of high-end sensors operating in vacuum, gas or liquid phase. Full article
Open AccessProceedings Characterization of Acoustic Sources by Optical Feedback Interferometry
Proceedings 2017, 1(4), 348; doi:10.3390/proceedings1040348
Published: 23 August 2017
PDF Full-text (424 KB)
Abstract
Sound can be described as the propagation of pressure variations in compressible media that involves compression and expansion and induces a change in the density of the medium. This change in acoustic pressure as it induces a change of the refractive index can
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Sound can be described as the propagation of pressure variations in compressible media that involves compression and expansion and induces a change in the density of the medium. This change in acoustic pressure as it induces a change of the refractive index can be measured by optical methods, the most recent being the optical feedback interferometry. With this technique, a laser diode is beaming on a reflective surface thus creating a cavity where the acoustic wave propagates. This paper presents anovel experimental technique to measure radiation pattern of acoustic sources based on optical feedback interferometry in a laser diode. Full article
Open AccessProceedings Analysis on Chattering Phenomena by the Tilt of the Proof Mass in MEMS Switch
Proceedings 2017, 1(4), 349; doi:10.3390/proceedings1040349
Published: 29 August 2017
PDF Full-text (831 KB)
Abstract
This paper reports an analysis on the relationship between the tilt of the proof mass in MEMS switch and the chattering phenomena. Low-g MEMS acceleration switch developed by Kim’s group was modelled in 2D and displacements of each end of the proof mass
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This paper reports an analysis on the relationship between the tilt of the proof mass in MEMS switch and the chattering phenomena. Low-g MEMS acceleration switch developed by Kim’s group was modelled in 2D and displacements of each end of the proof mass were analysed using RK 4th method. Some elementary assumptions were made to ease the modelling and analysis. The chattering time of the MEMS switch gets longer as the tilt of the proof mass increases. The reason is that the elongated travel distance of one end of proof mass increases the impact velocity and lengthens the bouncing back time. From the results, we found that the chattering phenomena can last very long even if the tilt of the proof mass is very small. Full article
Open AccessProceedings Torsional Moving Electric Field Sensor with Modulated Sensitivity and without Reference Ground
Proceedings 2017, 1(4), 350; doi:10.3390/proceedings1040350
Published: 8 August 2017
PDF Full-text (536 KB)
Abstract
A MEMS electric field sensor is presented with wide measurement resolution and adjustable sensitivity. The sense membrane is mounted using torsional springs and employs opposite biased electrodes on its surface, causing rotation in presence of an electric field, enabling operation without reference ground.
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A MEMS electric field sensor is presented with wide measurement resolution and adjustable sensitivity. The sense membrane is mounted using torsional springs and employs opposite biased electrodes on its surface, causing rotation in presence of an electric field, enabling operation without reference ground. Control of electrode bias enables adjustable linear measurement range from V/m to MV/m. Compared to earlier works with vertical moving sense membranes, higher sensitivity is achieved for the same bias voltage. Employing on-board electronics to enable independent resonant operation, a noise limited resolution of 3 V/m was achieved. Full article
Open AccessProceedings Large Tilt Angle Lorentz Force Actuated Micro-Mirror with 3 DOF for Optical Applications
Proceedings 2017, 1(4), 351; doi:10.3390/proceedings1040351
Published: 8 August 2017
PDF Full-text (801 KB)
Abstract
A versatile MEMS micro-mirror for optical platforms is presented, that operates using Lorentz force for actuation, resulting in low voltage operation. While maintaining below 20 mA drive current, this mirror has a tilting angle of over 50° and 20° around two diagonal axes
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A versatile MEMS micro-mirror for optical platforms is presented, that operates using Lorentz force for actuation, resulting in low voltage operation. While maintaining below 20 mA drive current, this mirror has a tilting angle of over 50° and 20° around two diagonal axes and a linear motion of 1.5 mm in vertical axis. Compared to other works, it has larger angle of rotation and additional out of plane linear motion. The temperature rise on the mirror is kept bellow 25 °C to avoid thermal expansion of the support flexures and curvature of the mirror. Full article
Open AccessProceedings Steady-State and Transient Response of a Micromechanical Broadband Shoaling Amplifier
Proceedings 2017, 1(4), 352; doi:10.3390/proceedings1040352
Published: 7 September 2017
PDF Full-text (933 KB)
Abstract
An in-plane MEMS broadband shoaling motion amplitude amplifier based on a coupled mass-spring system is presented. It is shown how the amplification amplitude can be traded for the operational bandwidth by design. Three devices with different numbers of masses (three, five and seven),
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An in-plane MEMS broadband shoaling motion amplitude amplifier based on a coupled mass-spring system is presented. It is shown how the amplification amplitude can be traded for the operational bandwidth by design. Three devices with different numbers of masses (three, five and seven), but all of them with the same total mass, were fabricated in silicon. The achieved baseline-amplification × bandwidth product ranges from 18.0 dB × 11.5 kHz for the seven mass device to 27.7 dB × 3.9 kHz for the three mass device. Transient recordings show amplification along the mass-spring-chain. The response time to reach the baseline amplification was found to be in the order of 10−4 s. This passive device can be used for ultra-low power structural and environmental monitoring (e.g., bridges, pipelines or rock-faces). Full article
Open AccessProceedings An Electromagnetically-Driven Piezoresistively Sensed CMOS MEMS Scanning Mirror for Projection Display
Proceedings 2017, 1(4), 353; doi:10.3390/proceedings1040353
Published: 8 August 2017
PDF Full-text (1080 KB)
Abstract
Bi-axial MEMS scanning mirrors are considered the key component for applications like laser scanning projectors and Lidars. Most studies have shown fabricated devices driven by open-loop operation without sensing, making it difficult to meet the requirements for practical applications. To facilitate bi-axial closed-loop
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Bi-axial MEMS scanning mirrors are considered the key component for applications like laser scanning projectors and Lidars. Most studies have shown fabricated devices driven by open-loop operation without sensing, making it difficult to meet the requirements for practical applications. To facilitate bi-axial closed-loop operation, this work presents an electro magnetically-driven scanning mirror with piezoresistive sensing conveniently implemented in a CMOS (complementary metal oxide semiconductor) process. The measured resonant frequencies with respect to the slow and fast axes are 4.3 and 36.05 kHz, respectively, with the aim to provide SXGA display resolution. Full article
Open AccessProceedings High Gauge Factor Piezoresistors Using Aluminium Induced Crystallisation of Silicon at Low Thermal Budget
Proceedings 2017, 1(4), 354; doi:10.3390/proceedings1040354
Published: 5 September 2017
PDF Full-text (1158 KB)
Abstract
This paper reports on polysilicon piezo-resistors that are fabricated at a low thermal budget using aluminium-induced-crystallization (AIC) of ultra-high-vacuum e-beam evaporated silicon films. By in-situ phosphorus doping of precursor amorphous silicon films e-beam evaporated at room temperature on aluminium layer, we are able
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This paper reports on polysilicon piezo-resistors that are fabricated at a low thermal budget using aluminium-induced-crystallization (AIC) of ultra-high-vacuum e-beam evaporated silicon films. By in-situ phosphorus doping of precursor amorphous silicon films e-beam evaporated at room temperature on aluminium layer, we are able to increase and control the gauge factor of the polysilicon films formed by AIC at 450 °C. Piezo-resistors made from the polysilicon films are integrated on microcantilever beams to measure their gauge factors. Gauge factors as high as 62 is obtained for 2 × 1018/cm3 phosphorus doping level in the precursor amorphous silicon film. The measured gauge factors are significantly higher than previously reported values for polysilicon films. Full article
Open AccessProceedings Tuning the Anti-Phase Mode Sensitivity to Vibrations of a MEMS Gyroscope
Proceedings 2017, 1(4), 355; doi:10.3390/proceedings1040355
Published: 8 August 2017
PDF Full-text (1261 KB)
Abstract
This paper proposes a stiffness correction method to improve the resilience to vibration of a dual-mass MEMS gyroscope with a particular focus near the resonance frequency of the anti-phase drive mode (fDa), i.e., its operational mode. Because of its balanced
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This paper proposes a stiffness correction method to improve the resilience to vibration of a dual-mass MEMS gyroscope with a particular focus near the resonance frequency of the anti-phase drive mode (fDa), i.e., its operational mode. Because of its balanced shape, this operating mode is ideally insensitive to vibrations. However, fabrication imperfections generates a residual sensitivity to parasitic vibrations that can disturb normal operation of the sensor. This work shows that the application of a DC voltage (Vtr) at the drive actuation electrode enables to decrease this sensitivity by a factor of at least 30 because of the stiffness tuning of the dual-mass structure. Experiments are performed to confirm this assumption and an efficient stiffness correction method is proposed to improve device operation. Full article
Open AccessProceedings Development of Catheter Flow Sensor for Breathing Measurements at Different Levels of Tracheobronchial Airway
Proceedings 2017, 1(4), 356; doi:10.3390/proceedings1040356
Published: 21 August 2017
PDF Full-text (3291 KB)
Abstract
We attempted to develop different sized catheter flow sensors for evaluating breathing characteristics at different levels of the tracheobronchial airway in a lung system. Two catheter flow sensors with 1.8 and 3.5 mm outer diameters were designed for measuring breathing characteristics in bronchus-
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We attempted to develop different sized catheter flow sensors for evaluating breathing characteristics at different levels of the tracheobronchial airway in a lung system. Two catheter flow sensors with 1.8 and 3.5 mm outer diameters were designed for measuring breathing characteristics in bronchus- and bronchiole- regions in the lung system, respectively. They were fabricated by using photolithography and heat shrinkable tube packaging processes. We experimentally investigated the fundamental sensor characteristic and found that the sensor output depended on the mean flow velocity. The developed catheter flow sensors also successfully detected the oscillating airflow produced by an artificial ventilator. Full article
Open AccessProceedings Micromachined Tube Type Thermal Flow Sensor for Adult-Sized Tracheal Intubation Tube
Proceedings 2017, 1(4), 357; doi:10.3390/proceedings1040357
Published: 7 September 2017
PDF Full-text (2189 KB)
Abstract
We designed and fabricated a tube-type thermal flow sensor for fabricating an adult-sized tracheal intubation tube device intended for clinical practice. The sensor film was packaged into the inside surface of the tube by interface tension and parylene coating, and a flow sensor
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We designed and fabricated a tube-type thermal flow sensor for fabricating an adult-sized tracheal intubation tube device intended for clinical practice. The sensor film was packaged into the inside surface of the tube by interface tension and parylene coating, and a flow sensor for an adult-sized tracheal intubation tube was successfully produced. We experimentally investigated flow rate detection and response time and found that the flow sensor fitted King’s model in terms of flow rate detection and has a sufficiently short response time of 59 ms. Thus, we concluded that the developed sensor will be applicable to measuring breathing characteristics of adults in the near future. Finally, the developed sensor was assembled into a tracheal intubation tube actually used in medical treatment. Full article
Open AccessProceedings Temperature Sensors Integrated into a CMOS Image Sensor
Proceedings 2017, 1(4), 358; doi:10.3390/proceedings1040358
Published: 7 September 2017
PDF Full-text (1298 KB)
Abstract
In this work, a novel approach is presented for measuring relative temperature variations inside the pixel array of a CMOS image sensor itself. This approach can give important information when compensation for dark (current) fixed pattern noise (FPN) is needed. The test image
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In this work, a novel approach is presented for measuring relative temperature variations inside the pixel array of a CMOS image sensor itself. This approach can give important information when compensation for dark (current) fixed pattern noise (FPN) is needed. The test image sensor consists of pixels and temperature sensors pixels (=Tixels). The size of the Tixels is 11 μm × 11 μm. Pixels and Tixels are placed next to each other in the active imaging array and use the same readout circuits. The design and the first measurements of the combined image-temperature sensor are presented. Full article
Open AccessProceedings Development of Small-Footprint Thermal Sensor Detecting Airflow at Mouth in Baby
Proceedings 2017, 1(4), 359; doi:10.3390/proceedings1040359
Published: 7 August 2017
PDF Full-text (1471 KB)
Abstract
This paper presents a novel tube flow sensor to measure airflow in mouths for detecting respiration and heartbeat signals of premature babies in incubators. A flow rate sensor with temperature compensation and a flow direction sensor were combined to decrease their footprint on
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This paper presents a novel tube flow sensor to measure airflow in mouths for detecting respiration and heartbeat signals of premature babies in incubators. A flow rate sensor with temperature compensation and a flow direction sensor were combined to decrease their footprint on a sensor film. The fabricated sensor film was assembled onto the inside surface of the tube, and its detection properties were investigated. The sensor output in the flow rate sensor obeyed King’s model. The value of output in the flow-direction sensor was changed in accordance with the change of the airflow direction. Full article
Open AccessProceedings Flexible Hydrogel Capacitive Pressure Sensor for Underwater Applications
Proceedings 2017, 1(4), 360; doi:10.3390/proceedings1040360
Published: 7 August 2017
PDF Full-text (697 KB)
Abstract
This paper reports development of a novel, flexible hydrogel based capacitive pressure sensor. It features a simple design of hydrogel thin film sandwiched between two gold electrodes. The sensor shows linear increase in output with increase in pressure. The microporous network of hydrogel
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This paper reports development of a novel, flexible hydrogel based capacitive pressure sensor. It features a simple design of hydrogel thin film sandwiched between two gold electrodes. The sensor shows linear increase in output with increase in pressure. The microporous network of hydrogel enables high water retention while its flexible and stretchable structure ensures usage over large areas. These factors, combined with its stability in water, make it an ideal candidate for underwater applications. Further, the physical and chemical properties of hydrogels can be tailored to tune the capacitance to specific sensing needs. Flexible arrays of capacitive sensors with hydrogel hold great potential for underwater smart skin applications. Full article
Open AccessProceedings Portable SAW Impedance Sensor Using a 1-Port Resonator Approach
Proceedings 2017, 1(4), 361; doi:10.3390/proceedings1040361
Published: 11 August 2017
PDF Full-text (374 KB)
Abstract
All actually used SAW sensors have in common that they analyze the transmission characteristics of propagating SAWs. Here, a portable device using the SAW-based impedance sensor type based on one interdigital transducer (IDT) simultaneously as SAW generator and sensor element (1-port approach) is
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All actually used SAW sensors have in common that they analyze the transmission characteristics of propagating SAWs. Here, a portable device using the SAW-based impedance sensor type based on one interdigital transducer (IDT) simultaneously as SAW generator and sensor element (1-port approach) is presented. The input port reflection coefficient S11 is measured at the IDT instead of the commonly used S21 transmission forward gain parameter. As a novelty, the so far required expensive vector network analyzer (VNA) is replaced by a hand-held device to measure the impedance spectrum of the SAW sensor by RF-gain-phase meters. The pivotal aspect of the portable system is the transfer of the sophisticated high frequency approach into a quasi-static one. This enables the use of simple lumped electronics without the need of impedance matching circuits. Proof-of-concept was carried out by measuring conductivities of phosphate-buffered solutions (PBS) and viscosities of glycerin. Sensitivities for conductivity of 64 Hz/S cm−1 and for viscosity of 122 mΩ/mPas were obtained, respectively. Full article
Open AccessProceedings Air-Coupled Ultrasonic Ferroelectret Receiver with Additional DC Voltage
Proceedings 2017, 1(4), 362; doi:10.3390/proceedings1040362
Published: 16 August 2017
PDF Full-text (750 KB)
Abstract
Highly sensitive air-coupled ultrasonic sensors are essential for various applications such as testing of composite materials. One of the major challenges for the development of air-coupled ultrasonic sensors is the impedance matching to air. With a lower acoustic impedance than the usual piezoelectric
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Highly sensitive air-coupled ultrasonic sensors are essential for various applications such as testing of composite materials. One of the major challenges for the development of air-coupled ultrasonic sensors is the impedance matching to air. With a lower acoustic impedance than the usual piezoelectric materials, charged cellular polypropylene film (cPP) offers better matching to air with a similar piezoelectric coefficient. The piezoelectric behaviour demonstrated by cPP comes from polarized air cells that create a permanent internal voltage. The sensitivity of the sensor varies with the application of an additional DC bias voltage. Thus, this work presents a cPP ultrasonic sensor with an improvement of up to 15 ± 1 dB on the signal-to-noise ratio. Full article
Open AccessProceedings Single-Element Omnidirectional Piezoelectric Ultrasound Transducer for under Water Communication
Proceedings 2017, 1(4), 363; doi:10.3390/proceedings1040363
Published: 16 August 2017
PDF Full-text (933 KB)
Abstract
This paper presents the design and fabrication procedure of a single-element omnidirectional piezoelectric ultrasound transducer, which can be utilized for under water communication. The transducer consists of a spherical silicon infiltrated silicon carbide (Si-SiC) body and is able to perform communication at 160
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This paper presents the design and fabrication procedure of a single-element omnidirectional piezoelectric ultrasound transducer, which can be utilized for under water communication. The transducer consists of a spherical silicon infiltrated silicon carbide (Si-SiC) body and is able to perform communication at 160 kHz with a Q factor of about 5.6 over a distance of more than one meter. The circumferential pressure amplitude of the beam pattern of the transducer varies less than 10 dB, which allows reliable communication between different transducers at an arbitrary orientation with respect to each other. Full article
Open AccessProceedings A Piezoelectric Micromachined Ultrasound Transducers (pMUT) Array, for Wide Bandwidth Underwater Communication Applications
Proceedings 2017, 1(4), 364; doi:10.3390/proceedings1040364
Published: 7 August 2017
PDF Full-text (1030 KB)
Abstract
This paper presents an array of five aluminum nitride (AlN) based piezoelectric micromachined ultrasound transducers (pMUTs) with different dimensions operating at 540–2360 kHz in air. Due to the damping effect of water or oil on the vibration of each individual pMUT, their frequency
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This paper presents an array of five aluminum nitride (AlN) based piezoelectric micromachined ultrasound transducers (pMUTs) with different dimensions operating at 540–2360 kHz in air. Due to the damping effect of water or oil on the vibration of each individual pMUT, their frequency response tends to merge and significantly increases the bandwidth of the pMUTs array. The device is fabricated based on the deep reactive ion etching (DRIE) process on the backside of an SOI wafer to realize the circular diaphragms. Theoretical calculations, measured frequency response, simulation results, and detail of the fabrication are explained in this paper. Full article
Open AccessProceedings Mechanical Characterization of (La,Sr)MnO3 Microbridges for Thermometric Applications
Proceedings 2017, 1(4), 365; doi:10.3390/proceedings1040365
Published: 28 August 2017
PDF Full-text (875 KB)
Abstract
MicroElectroMechanical Systems (MEMS) made of heterostructures of crystalline oxide materials with targeted physical properties may be applied as sensors having different integrated functionalities. In this work, we explore the feasibility of manganite thin film based epitaxial MEMS for thermometric micromechanical sensing. We investigate
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MicroElectroMechanical Systems (MEMS) made of heterostructures of crystalline oxide materials with targeted physical properties may be applied as sensors having different integrated functionalities. In this work, we explore the feasibility of manganite thin film based epitaxial MEMS for thermometric micromechanical sensing. We investigate the mechanical properties of La1−xSrxMnO3, with x ≈ 1/3, freestanding microbridges as a function of temperature for applications in the field of micromechanical temperature sensors. Full article
Open AccessProceedings Thin Film PZT Acoustic Sensor for Fully Implantable Cochlear Implants
Proceedings 2017, 1(4), 366; doi:10.3390/proceedings1040366
Published: 22 August 2017
PDF Full-text (959 KB)
Abstract
This paper presents design and fabrication of a MEMS-based thin film piezoelectric transducer to be placed on an eardrum for fully-implantable cochlear implant (FICI) applications. Resonating at a specific frequency within the hearing band, the transducer senses eardrum vibration and generates the required
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This paper presents design and fabrication of a MEMS-based thin film piezoelectric transducer to be placed on an eardrum for fully-implantable cochlear implant (FICI) applications. Resonating at a specific frequency within the hearing band, the transducer senses eardrum vibration and generates the required voltage output for the stimulating circuitry. Moreover, high sensitivity of the sensor, 391.9 mV/Pa @900 Hz, decreases the required power for neural stimulation. The transducer provides highest voltage output in the literature (200 mVpp @100 dB SPL) to our knowledge. A multi-frequency piezoelectric sensor, covering the daily acoustic band, is designed based on the test results and validated through FEA. The implemented system provides mechanical filtering, and mimics the natural operation of the cochlea. Herewith, the proposed sensor overcomes the challenges in FICI operations and demonstrates proof-of-concept for next generation FICIs. Full article
Open AccessProceedings Multiresonator-Based Printable Chipless RFID for Relative Humidity Sensing
Proceedings 2017, 1(4), 367; doi:10.3390/proceedings1040367
Published: 7 August 2017
PDF Full-text (368 KB)
Abstract
We present a chipless RFID for relative humidity sensing. It consists of three spiral resonators coupled to a 50 Ω microstrip line. One resonator is used for humidity sensing, and the other two are used for encoding ID. The sensing resonator is coated
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We present a chipless RFID for relative humidity sensing. It consists of three spiral resonators coupled to a 50 Ω microstrip line. One resonator is used for humidity sensing, and the other two are used for encoding ID. The sensing resonator is coated with a humidity sensitive polymer film. As the relative humidity changes the permittivity of the polymer film varies changing the resonant frequency of the sensing resonator. Results show that a dedicated resonator can sense relative humidity over 21–53% range with 2.5 MHz/%RH sensitivity whereas the other two resonators can represent the ID. The sensor does not require any IC and is amenable to low-cost production using printed electronic technology. Full article
Open AccessProceedings Modelling and Experimental Analysis of a Magnetic Material Actuator: Towards Wireless Implantable Devices
Proceedings 2017, 1(4), 368; doi:10.3390/proceedings1040368
Published: 21 August 2017
PDF Full-text (528 KB)
Abstract
This paper presents a wireless diaphragm actuator and focuses on a lumped parameter grey-box model capable of simulating actuation displacement. Here, modelling aims to provide further insight into this smart material actuator and help facilitate design into new implantable applications. Model parameters were
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This paper presents a wireless diaphragm actuator and focuses on a lumped parameter grey-box model capable of simulating actuation displacement. Here, modelling aims to provide further insight into this smart material actuator and help facilitate design into new implantable applications. Model parameters were calibrated to a prototype actuator using experimental data and a genetic algorithm optimisation. The model was validated against experimental data and showed a good ability to simulate both static and dynamic diaphragm displacement. Full article
Open AccessProceedings Photoelectrical Hydrogen Sensor Based on Pd/Anodic Oxide/InP Structure
Proceedings 2017, 1(4), 369; doi:10.3390/proceedings1040369
Published: 17 August 2017
PDF Full-text (279 KB)
Abstract
Pd–anodic oxide–InP metal–oxide–semiconductor (MOS) structures are fabricated to develop a hydrogen sensor capable of effectively operating at room temperature. Through palladium amount varying the signal recovery time has been improved (became shorter). Decrease of photovoltage and strong increase of photocurrent were observed for
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Pd–anodic oxide–InP metal–oxide–semiconductor (MOS) structures are fabricated to develop a hydrogen sensor capable of effectively operating at room temperature. Through palladium amount varying the signal recovery time has been improved (became shorter). Decrease of photovoltage and strong increase of photocurrent were observed for illuminated by LED structures under hydrogen pulse exposure. The gas testing was carried out in 0.1–10% hydrogen in nitrogen, and in 100% hydrogen. As a result, low power-consumption hydrogen sensor with a fast response-recovery time 1/20 s. was developed. Full article
Open AccessProceedings Pulse Wave Monitoring for Arterial Stiffness Detection Using a Simple Portable Tonometer
Proceedings 2017, 1(4), 370; doi:10.3390/proceedings1040370
Published: 24 August 2017
PDF Full-text (1305 KB)
Abstract
The work presented in this paper concerns the design, fabrication and test of a simple portable device able to measure in real time the cardiac frequency and the pulse wave, plus the pulse velocity in specific conditions (carotid and femoral locations). The sensing
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The work presented in this paper concerns the design, fabrication and test of a simple portable device able to measure in real time the cardiac frequency and the pulse wave, plus the pulse velocity in specific conditions (carotid and femoral locations). The sensing part is based on a thin film technology embedded in polymer and the data processing part is based on a classical pre-amplifying circuit associated with digitalization and shape detection algorithm. The whole device has been chosen as one demonstrator in the EveryWear project of the PROXIMA mission launched by the European Space Agency, the France’s space agency CNES with space medicine specialists MEDES, to estimate the arterial stiffness variations under microgravity conditions and weightlessness. Raw data are stored through the remote tablet application and will be later processed using Matlab. Full article
Open AccessProceedings Piezo Resistive Read-Out Contact Resonance Spectroscopy for Material and Layer Analysis at High-Aspect-Ratio Geometries
Proceedings 2017, 1(4), 371; doi:10.3390/proceedings1040371
Published: 24 August 2017
PDF Full-text (1209 KB)
Abstract
A piezo resistive, phase locked loop (PLL) controlled micro tactile measurement system for contact resonance spectroscopy (CRS) at high-aspect-ratio geometries was developed and characterised. Therefore, a piezo resistive silicon cantilever with a silicon tip at its free end was brought into contact with
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A piezo resistive, phase locked loop (PLL) controlled micro tactile measurement system for contact resonance spectroscopy (CRS) at high-aspect-ratio geometries was developed and characterised. Therefore, a piezo resistive silicon cantilever with a silicon tip at its free end was brought into contact with a sample surface and excited into resonance by a piezo actuator. The resonance frequency of the contacted cantilever was tracked by a homemade closed-loop PLL circuit. Different materials and layer thicknesses of photo resist (PR) on silicon were used to validate the system. To optimise the sensitivity and efficiency of the measurement system, amplitude and phase of the cantilever in surface contact were analysed under different contact forces and excitation amplitudes. Full article
Open AccessProceedings Design, Modeling, and Characterization of a Bionically Inspired Integrated Micro-Flapper for Cooling and Venting Applications
Proceedings 2017, 1(4), 372; doi:10.3390/proceedings1040372
Published: 23 August 2017
PDF Full-text (536 KB)
Abstract
A novel, integrated micromechanical actuator based on the principle of undulatory fish locomotion and intended for efficient on-chip cooling or venting applications is conceived and designed for an aluminum nitride-based thin-film technology applying coupled piezoelectric, mechanical, and fluidic analyses. The results of the
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A novel, integrated micromechanical actuator based on the principle of undulatory fish locomotion and intended for efficient on-chip cooling or venting applications is conceived and designed for an aluminum nitride-based thin-film technology applying coupled piezoelectric, mechanical, and fluidic analyses. The results of the investigations prove that an undulatory motion of the fin-like micro-flapper yields a significant higher, directed fluidic net flow compared to resonant-like motion. First prototypes have been manufactured and characterized applying laser Doppler vibrometry (LDV). Full article
Open AccessProceedings Impact of High Coupling Factor in Absolute Distance Measurement with Self-Mixing Interferometry
Proceedings 2017, 1(4), 373; doi:10.3390/proceedings1040373
Published: 16 August 2016
PDF Full-text (513 KB)
Abstract
Absolute distance measurement by means of a self-mixing interferometer (SMI) can be obtained by modulating the laser frequency. This modulation is typically achieved through the modulation of the laser injection current with a triangle waveform. Various strategies have been proposed to increase the
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Absolute distance measurement by means of a self-mixing interferometer (SMI) can be obtained by modulating the laser frequency. This modulation is typically achieved through the modulation of the laser injection current with a triangle waveform. Various strategies have been proposed to increase the performances and recent researches have shown real-time performance of SMI with resolution reaching 100 μm for distances up to 2 m. In the present paper, we demonstrate for the first time, both experimentally and by modeling, that with high coupling factors between the laser and the target, disappearance of interferometric fringes occurs that can strongly affect the measurement reliability. Full article
Open AccessProceedings On-Chip Platform for Slack-Free Carbon Nanotube Resonators
Proceedings 2017, 1(4), 374; doi:10.3390/proceedings1040374
Published: 8 August 2017
PDF Full-text (1316 KB)
Abstract
This work describes an on-chip integrated micro-actuator device for slack-free carbon nanotube (CNT) resonators, improving frequency tunability and Q factor and to study non-linear mode interaction. The device fabricated on SOI wafer with low thermal budget (<600 K) encompasses a restricted symmetrical out-of-plane
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This work describes an on-chip integrated micro-actuator device for slack-free carbon nanotube (CNT) resonators, improving frequency tunability and Q factor and to study non-linear mode interaction. The device fabricated on SOI wafer with low thermal budget (<600 K) encompasses a restricted symmetrical out-of-plane vibration and a stiff in-plane electro-thermal actuator with a displacement of ~112 nm at 2.7 mW. This corresponds to 5.6% of strain for a 2 μm long suspended carbon nanotube. The in-plane mechanical resonance designed to be far from CNT resonances in MHz regime is measured at 209 kHz. The design is optimized for low power consumption, electrical and thermal isolation and is customized for dry transfer of CNTs. Full article
Open AccessProceedings Nanomechanical Traceable Metrology of Vertically Aligned Silicon and Germanium Nanowires by Nanoindentation
Proceedings 2017, 1(4), 375; doi:10.3390/proceedings1040375
Published: 9 August 2017
PDF Full-text (524 KB)
Abstract
Silicon and germanium pillar structures (i.e., micro- and nanowires) were fabricated by a top-down approach including nanoimprint lithography and cryogenic dry etching. Various etching parameters were tested to ensure a reliable fabrication process. The impression of nanomechanical properties of such 3-D structures were
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Silicon and germanium pillar structures (i.e., micro- and nanowires) were fabricated by a top-down approach including nanoimprint lithography and cryogenic dry etching. Various etching parameters were tested to ensure a reliable fabrication process. The impression of nanomechanical properties of such 3-D structures were extracted experimentally by nanoindentation showing promising and comparative results to utilize such nanostructures as small force artefacts. Full article
Open AccessProceedings Wall Shear Stress Calorimetric Micro-Sensor Designed for Flow Separation Detection and Active Flow Control
Proceedings 2017, 1(4), 376; doi:10.3390/proceedings1040376
Published: 9 August 2017
PDF Full-text (612 KB)
Abstract
This paper presents an efficient and high-sensitive micro-sensor designed for wall shear stress measurement. The main technical application targeted is flow separation detection for closed-loop active flow control. The sensor is a temperature-resistance transducer operating on heat transfer. The device is micro-structured with
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This paper presents an efficient and high-sensitive micro-sensor designed for wall shear stress measurement. The main technical application targeted is flow separation detection for closed-loop active flow control. The sensor is a temperature-resistance transducer operating on heat transfer. The device is micro-structured with three substrate-free wires presenting a high aspect ratio, and periodic perpendicular micro-bridges ensuring mechanical toughness and thermal insulation. This design achieves a homogeneous temperature distribution along the wires. Welded on a flexible printed circuit, the sensor is wall-mounted on a wind tunnel. The experiments, conducted in both attached and separated flow configurations, demonstrate the sensor sensitivity to wall shear stress up to 2.4 Pa and the ability of the 3-wires based design to perform flow direction sensing for back-flow detection. Full article
Open AccessProceedings Nanogap Pirani Sensor Operating in Constant Temperature Mode for Near Atmospheric Pressure Measurements
Proceedings 2017, 1(4), 377; doi:10.3390/proceedings1040377
Published: 5 September 2017
PDF Full-text (721 KB)
Abstract
This paper presents a high sensitive micro-sensor designed for pressure measurements in a wide range around atmospheric pressure, for application in aerodynamics. The sensor is a temperature-resistance transducer operating with the Pirani effect, which states that below a certain pressure limit, the thermal
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This paper presents a high sensitive micro-sensor designed for pressure measurements in a wide range around atmospheric pressure, for application in aerodynamics. The sensor is a temperature-resistance transducer operating with the Pirani effect, which states that below a certain pressure limit, the thermal conductivity of a gas is pressure-dependent. The sensor presents a wide measurement range between 10 kPa and about 800 kPa, in both constant current and constant temperature mode. The last mode enables high-sensitive measurements with a maximum of sensitivity around atmospheric pressure, enabling the use of the sensor for applications in aerodynamics and fluid dynamics, such as active flow control. Full article
Open AccessProceedings Neutral Argon Plasma in Minimally Invasive Medical Devices for Therapy
Proceedings 2017, 1(4), 378; doi:10.3390/proceedings1040378
Published: 11 August 2017
PDF Full-text (486 KB)
Abstract
This paper presents a solution to implement neutral argon plasma (NAP) in minimally invasive medical devices (MIMD) for therapy in endoscopy. The NAP system is composed by compressed inert gas (argon), two electrodes and a high-voltage source to ionize the argon. The miniaturization
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This paper presents a solution to implement neutral argon plasma (NAP) in minimally invasive medical devices (MIMD) for therapy in endoscopy. The NAP system is composed by compressed inert gas (argon), two electrodes and a high-voltage source to ionize the argon. The miniaturization of an argon reservoir is required. The finite element method simulation of a small reservoir of 304 L stainless steel with 0.2 mm thick at 7 atm of pressure was performed. The results show maximum total deformation of 40 μm and maximum equivalent stress of 160 MPa, with no permanent deformation of argon reservoir. Full article
Open AccessProceedings High Accuracy MEMS Pressure Sensor Based on Quartz Crystal Resonator
Proceedings 2017, 1(4), 379; doi:10.3390/proceedings1040379
Published: 11 August 2017
PDF Full-text (526 KB)
Abstract
This paper reports a high accuracy oil-filled MEMS absolute pressure sensor based on quartz crystal double-ended tuning fork (DETF) resonator, which is suitable for application in ocean, petroleum, meteorological, aerospace and spacecraft field, etc. The pressure sensing unit is mainly composed of DETF
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This paper reports a high accuracy oil-filled MEMS absolute pressure sensor based on quartz crystal double-ended tuning fork (DETF) resonator, which is suitable for application in ocean, petroleum, meteorological, aerospace and spacecraft field, etc. The pressure sensing unit is mainly composed of DETF resonator, diaphragm and back cavity structure. These pieces are all fabricated by quartz crystal using MEMS process, and are bonded together as ‘sandwich’ structure to form the absolute pressure sensing unit using glass frit under low temperature and vacuum condition. This process could effectively eliminate the thermal stress effect and form the reference vacuum cavity. The isolated packaged pressure sensor is composed of corrugated stainless steel diaphragm, silicone oil, pressure sensing unit and ceramic base package. The experimental results show that the accuracy is up to ±0.033% FS in the pressure range 0~300 kPa over the temperature range −20 °C~+45 °C. Full article
Open AccessProceedings Tuneable Q-Factor of MEMS Cantilevers with Integrated Piezoelectric Thin Films
Proceedings 2017, 1(4), 380; doi:10.3390/proceedings1040380
Published: 21 August 2017
PDF Full-text (1544 KB)
Abstract
When targeting the integration of atomic force microscopes (AFM) into vacuum environments (e.g., scanning electron microscopes), a tunable Q-factor of the resonating AFM cantilever is a key feature to enable high speed measurements with high local resolution. To achieve this goal, an additional
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When targeting the integration of atomic force microscopes (AFM) into vacuum environments (e.g., scanning electron microscopes), a tunable Q-factor of the resonating AFM cantilever is a key feature to enable high speed measurements with high local resolution. To achieve this goal, an additional stimulus is applied to the cantilever with respect to the mechanical stimulus provided by the macroscopic piezoelectric actuator. This additional stimulus is generated by an aluminium nitride based piezoelectric actuator integrated on the cantilever, which is driven by a phase shifted excitation. With this approach, the mechanical Q-factor measured with a laser Doppler vibrometer (LDV) in vacuum is electrically decreased by a factor of up to 1.7. Full article
Open AccessProceedings Effect of Electrode Configuration on High Temperature Thickness Shear Gallium Phosphate Transducer
Proceedings 2017, 1(4), 381; doi:10.3390/proceedings1040381
Published: 25 August 2017
PDF Full-text (1018 KB)
Abstract
Gallium phosphate single crystal has a very stable thermal response, ideal for high temperature applications such as transducers for in-service monitoring of HT infrastructure in Power and Oil & Gas industries. Broadband transducers are designed to resonate with a specific mode of vibration
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Gallium phosphate single crystal has a very stable thermal response, ideal for high temperature applications such as transducers for in-service monitoring of HT infrastructure in Power and Oil & Gas industries. Broadband transducers are designed to resonate with a specific mode of vibration within a frequency range of interest. This desired frequency response depends on how the transducer is mounted on the structure and the target defect sensitivity. Electrode configurations are defined to achieve the transducer design. This study investigates the parallel and wrap-around electrode configurations on the transducer response. An electro-mechanical finite element model was developed to analyse the transducer response and predicted a disparity in the modes of vibration between the two configurations within the same frequency range. This model was experimentally validated by measuring the displacement patterns using 3D Laser Doppler Vibrometry. Full article
Open AccessProceedings High Sensitivity Ultraviolet Light Off-Stoichiometric Silicon Oxide-Based Sensors
Proceedings 2017, 1(4), 382; doi:10.3390/proceedings1040382
Published: 25 August 2017
PDF Full-text (391 KB)
Abstract
We have developed a UV silicon detector made of silicon and off-stoichiometric silicon dioxide that shows high efficiency and is completely compatible with silicon devices technology. The silicon-based UV detector present a solar cell-like structure which does not require any voltage source. In
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We have developed a UV silicon detector made of silicon and off-stoichiometric silicon dioxide that shows high efficiency and is completely compatible with silicon devices technology. The silicon-based UV detector present a solar cell-like structure which does not require any voltage source. In addition, an off-stoichiometric silicon dioxide film (Silicon Rich Oxide) with silicon nanocrystals has been integrated to this structure. It is shown that the spectral response is due to the high photoluminescence of Si nanocrystals in the visible region when illuminated with UV light and an increase of 100% in the UV detector efficiency is observed with respect to conventional silicon dioxide layers. Full article
Open AccessProceedings Servo-Assisted Position-Feedback MEMS Force Sensor with Tunable Sensitivity and Sub-Nanonewton Range
Proceedings 2017, 1(4), 383; doi:10.3390/proceedings1040383
Published: 28 August 2017
PDF Full-text (1275 KB)
Abstract
A Micro Electro-Mechanical System (MEMS) that allows to measure an external force applied to a probe tip exploiting an electrical servo-assisted mechanism based on position feedback is presented. The sensor architecture keeps the position of the probe tip fixed by driving a pair
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A Micro Electro-Mechanical System (MEMS) that allows to measure an external force applied to a probe tip exploiting an electrical servo-assisted mechanism based on position feedback is presented. The sensor architecture keeps the position of the probe tip fixed by driving a pair of variable-area electrostatic actuators in a feedback loop controlled by a variable-gap capacitive sensor. By adjusting specific loop parameters, the force sensitivity can be finely tuned electrically. Sub-nanonewton measurement range is achieved with high flexibility in setting the tip working point, making the system promising for measuring forces generated by living biological cells. Full article
Open AccessProceedings Investigation on the Influence of Solvents on MWCNT-PDMS Nanocomposite Pressure Sensitive Films
Proceedings 2017, 1(4), 384; doi:10.3390/proceedings1040384
Published: 16 August 2017
PDF Full-text (595 KB)
Abstract
Nanocomposites based on Multi-Walled Carbon Nanotubes (MWCNT)—Polydimethylsiloxane (PDMS) polymer achieve pressure sensors sensitive even at very low pressure less than 5 N. For film homogeneity and sensitivity, fabrication procedure and especially the dispersion quality are decisive. Because of high viscosity of PDMS, a
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Nanocomposites based on Multi-Walled Carbon Nanotubes (MWCNT)—Polydimethylsiloxane (PDMS) polymer achieve pressure sensors sensitive even at very low pressure less than 5 N. For film homogeneity and sensitivity, fabrication procedure and especially the dispersion quality are decisive. Because of high viscosity of PDMS, a solvent is necessary. Solvents exhibit themselves different dispersion quality and in turn different piezoresistive response of the films under pressure. In this paper, the influence of solvents in fabricating the nanocomposite is investigated considering dispersion quality and stability. The best dispersion stability was achieved with isopropanol and the nanocomposite show better results considering sensitivity and hysteresis behavior under pressure. Full article
Open AccessProceedings Micro-Grippers with Femtosecond-Laser Machined In-Plane Agonist-Antagonist SMA Actuators Integrated on Wafer-Level by Galvanic Riveting
Proceedings 2017, 1(4), 385; doi:10.3390/proceedings1040385
Published: 4 August 2017
PDF Full-text (2281 KB)
Abstract
In-plane shape memory alloy (SMA) actuators operated in agonist-antagonist mode are integrated on silicon micro-grippers. The actuator elements are cut out of sheet material in a femtosecond laser ablation process. The assembly process is carried out on wafer-level, and the fixation realized by
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In-plane shape memory alloy (SMA) actuators operated in agonist-antagonist mode are integrated on silicon micro-grippers. The actuator elements are cut out of sheet material in a femtosecond laser ablation process. The assembly process is carried out on wafer-level, and the fixation realized by galvanic riveting. The initial deformation of the differential actuators needed to access their actuation potential is implemented during the gripper connection to energy supply. Full article
Open AccessProceedings Development of a MEMS Plate Based on Thin-Film Piezoelectric AlN Actuators for Biological Applications
Proceedings 2017, 1(4), 386; doi:10.3390/proceedings1040386
Published: 9 August 2017
PDF Full-text (975 KB)
Abstract
This paper presents the development of a lab-on-chip system based on the use of local vibrations to mechanically stimulate biological materials. It reports on the development and characterization of a piezoelectric actuators driven system designed to operate in liquid media. The microfluidic packaging
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This paper presents the development of a lab-on-chip system based on the use of local vibrations to mechanically stimulate biological materials. It reports on the development and characterization of a piezoelectric actuators driven system designed to operate in liquid media. The microfluidic packaging of the Micro Electro Mechanical System (MEMS) is first presented. Then, electromechanical measurements done to calibrate our system are compared with Finite Element Method (FEM) simulations. These results are the first steps for implementation of piezoelectric MEMS to study mechanical response of biological cells at the population level. Full article
Open AccessProceedings Soft Triboelectric Band for Sensing of and Energy Scavenging From Body Motion
Proceedings 2017, 1(4), 387; doi:10.3390/proceedings1040387
Published: 9 August 2017
PDF Full-text (2506 KB)
Abstract
We manifest a new method of developing wearable triboelectric band for self-powerd gesture sensing and power generating. Film casting technique, that is easily scalable, was used to patterned soft stretchable elastomers and conductive carbon based composites. The developed triboelectric band showed the capabilities
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We manifest a new method of developing wearable triboelectric band for self-powerd gesture sensing and power generating. Film casting technique, that is easily scalable, was used to patterned soft stretchable elastomers and conductive carbon based composites. The developed triboelectric band showed the capabilities of detecting locomotion of elbow and knee movement and provides electrical signal in response. The rms voltage, current and power of 2.9 V, 0.3 μA and 1.6 μW for elbow stretching, and 1.1 V, 0.11 μA and 0.22 μW for knee stretching was obtained for the optimum load of 10.1 MΩ at operational frequency of 1 ± 0.1 Hz. Full article
Open AccessProceedings A Spherical Directional Anemometer Sensor System
Proceedings 2017, 1(4), 388; doi:10.3390/proceedings1040388
Published: 4 August 2017
PDF Full-text (1434 KB)
Abstract
In this work, the authors propose a novel directional anemometric system, showing a compact design and the absence of external mechanical moving parts. The measuring principle is based on a dual channel spherical wind conveyor structure, combined with a pressure difference sensing technique
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In this work, the authors propose a novel directional anemometric system, showing a compact design and the absence of external mechanical moving parts. The measuring principle is based on a dual channel spherical wind conveyor structure, combined with a pressure difference sensing technique of the conveyed air flows by the employment of electromagnetic inductive transducers. Full article
Open AccessProceedings Study of Elongation and Temperature Effects on Nanocomposite Based on Elastic Fiber
Proceedings 2017, 1(4), 389; doi:10.3390/proceedings1040389
Published: 7 August 2017
PDF Full-text (634 KB)
Abstract
Stretchable sensors are increasingly demanded in the fields of smart textiles for sports, military and medical industry. In this work, we propose novel elongation sensitive elastic fibers made up of Multi-Walled Carbon Nanotubes (MWCNT), Polyester and Polyurethane. The entire fiber is encased with
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Stretchable sensors are increasingly demanded in the fields of smart textiles for sports, military and medical industry. In this work, we propose novel elongation sensitive elastic fibers made up of Multi-Walled Carbon Nanotubes (MWCNT), Polyester and Polyurethane. The entire fiber is encased with natural rubber (NR) for protection against mechanical, electrical and humidity external influences. With this fiber, it is possible to reach elongations above 100%. It can be fabricated in different sizes according to application requirements. The relationship between fiber resistance and its physical modifications was measured at different elongations and temperatures. The experimental results show a high sensitivity and a stable temperature behavior. Full article
Open AccessProceedings Linear Position Sensing through Conductive Wall without Permanent Magnet
Proceedings 2017, 1(4), 390; doi:10.3390/proceedings1040390
Published: 8 August 2017
PDF Full-text (1019 KB)
Abstract
A linear position sensor for pneumatic actuators is presented. Position of the piston rod made of ferromagnetic material is detected by low frequency magnetic field which penetrates the aluminum wall of the cylinder. The sensor consists of an array of integrated fluxgate sensors
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A linear position sensor for pneumatic actuators is presented. Position of the piston rod made of ferromagnetic material is detected by low frequency magnetic field which penetrates the aluminum wall of the cylinder. The sensor consists of an array of integrated fluxgate sensors and two excitation saddle coils mounted outside the actuator. The method does not need a permanent magnet attached to the piston as required by common magnetic position sensors. Full article
Open AccessProceedings Low Impedance ALD HfO2 Partially-Filled-Gap Flexural and Bulk MEMS Resonators Piezoresistively Detected for Distributed Mass Sensing
Proceedings 2017, 1(4), 391; doi:10.3390/proceedings1040391
Published: 9 August 2017
PDF Full-text (3356 KB)
Abstract
This paper reports the design and characterization of partially-filled-gap capacitive MEMS resonators for distributed mass sensing applications. By filling the gap with HfO2, the coupling coefficient between electrode-resonator increases by ×6.67 times and the motional resistance decreases by ×12 times in
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This paper reports the design and characterization of partially-filled-gap capacitive MEMS resonators for distributed mass sensing applications. By filling the gap with HfO2, the coupling coefficient between electrode-resonator increases by ×6.67 times and the motional resistance decreases by ×12 times in comparison with its counterpart in air. An improvement by a factor of ×5.6 in the Signal-To-Noise Ratio (SNR) for DC bias up to ×2.8 lower is accomplished by performing a piezoresistive detection instead of capacitive detection. Quality factor (Q) of 11,350 and motional resistances (Rm) of 926 Ω have been achieved for Parallel Beam Resonators (PBR) vibrating at 22.231 MHz. For the first time, ALD HfO2 partially-filled-gap MEMS resonators are proven to achieve inertial distributed mass sensitivities of the order of 4.28 kHz/pg for beam-type and 1.8k Hz/pg for disk resonators. Full article
Open AccessProceedings Piezoelectric Actuators for In-Liquid Particle Manipulation in Microfluidic Applications
Proceedings 2017, 1(4), 392; doi:10.3390/proceedings1040392
Published: 8 August 2017
PDF Full-text (1086 KB)
Abstract
The possibility to generate acoustic modes based on FPWs (Flexural Plate Waves) in a generic non-piezoelectric substrate for microfludic applications by means of piezoelectric actuators has been explored and described in this paper. The FPW acoustic modes are generated by means of actuators
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The possibility to generate acoustic modes based on FPWs (Flexural Plate Waves) in a generic non-piezoelectric substrate for microfludic applications by means of piezoelectric actuators has been explored and described in this paper. The FPW acoustic modes are generated by means of actuators made of Lead Zirconate Titanate (PZT) layers with InterDigital Transducers (IDTs) screen-printed on alumina (Al2O3) substrate. The experimental results show that, by exciting the resonances of the actuators, circular vortex rotations are obtained in a fluid drop placed on the substrate between the IDTs. Micrometric particles dispersed in the drop allow to demonstrate that standing waves can be generated in the liquid obtaining particle accumulation along circular lines. These results suggest the possibility to employ the proposed actuators for fluid mixing and controlled positioning of dispersed particles. Full article
Open AccessProceedings The First Frequency-Modulated (FM) Pitch Gyroscope
Proceedings 2017, 1(4), 393; doi:10.3390/proceedings1040393
Published: 8 August 2017
PDF Full-text (977 KB)
Abstract
In this work, the mechanical design and the experimental validation of a micro-electromechanical frequency-modulated (FM) pitch gyroscope are presented. The proposed device is fabricated through the ThELMA © surface micromachining process of STMicroelectronics and it represents, to the authors’ knowledge, the first small-footprint
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In this work, the mechanical design and the experimental validation of a micro-electromechanical frequency-modulated (FM) pitch gyroscope are presented. The proposed device is fabricated through the ThELMA © surface micromachining process of STMicroelectronics and it represents, to the authors’ knowledge, the first small-footprint (690 µm × 946 µm) prototype of FM gyroscope able to measure an in-plane angular rate. The measured scale factor, defined as the mean angular gain, equals 0.973 Hz/Hz, in close agreement with theoretical predictions. It depends only on the mass distribution in the mechanical structure and is, consequently, not influenced by environmental fluctuations. Full article
Open AccessProceedings Sensitivity of Piezoelectric Ultrasonic Microsensors with Sol-Gel Derived PZT Films Prepared through Various Pyrolysis Temperatures
Proceedings 2017, 1(4), 394; doi:10.3390/proceedings1040394
Published: 11 August 2017
PDF Full-text (530 KB)
Abstract
Sensitivity of piezoelectric-diaphragm type ultrasonic microsensors were investigated with sol-gel derived lead-zirconate-titanate (PZT) films prepared through various pyrolysis temperatures. The residual stress of the PZT film should be precisely controlled because the sensor diaphragms show static deflection by buckling and highly sensitive sensors
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Sensitivity of piezoelectric-diaphragm type ultrasonic microsensors were investigated with sol-gel derived lead-zirconate-titanate (PZT) films prepared through various pyrolysis temperatures. The residual stress of the PZT film should be precisely controlled because the sensor diaphragms show static deflection by buckling and highly sensitive sensors have been realized on upward-buckled diaphragms whose buckling direction and deflection are determined by the stress. The films were prepared under pyrolysis temperatures in the range from 250 °C to 400 °C and for (100)- or (111)-orientation. Higher pyrolysis temperature resulted in lower film stress and larger buckling deflection of the diaphragms. The (111)-oriented films showed the higher sensitivity in the higher pyrolysis temperatures. The (100)-oriented films, however, showed the highest sensitivity in the lowest pyrolysis temperature (250 °C). Full article
Open AccessProceedings Contactless Interrogation System for Capacitive Sensors with Time-Gated Technique
Proceedings 2017, 1(4), 395; doi:10.3390/proceedings1040395
Published: 8 August 2017
PDF Full-text (944 KB)
Abstract
This paper presents a measurement technique and system for the contactless interrogation of capacitive sensors via electromagnetic coupling. The interrogation unit employs a primary coil to periodically excite the capacitive sensor connected to a secondary coil forming an LC resonant circuit. When the
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This paper presents a measurement technique and system for the contactless interrogation of capacitive sensors via electromagnetic coupling. The interrogation unit employs a primary coil to periodically excite the capacitive sensor connected to a secondary coil forming an LC resonant circuit. When the excitation to the primary coil is switched off the damped response of the LC circuit is detected. As a fundamental advantage compared to techniques based on reflected impedance, this approach ensures that the readout frequency is to first order independent of the interrogation distance between the two coils. The system has been tested with reference capacitors and with a capacitive liquid level sensor. The experimental results are in a good agreement with theoretical expectations and show a sensitivity of about −23 kHz/pF at 5.4 MHz and the possibility to operate with interrogation distances up to few centimeters. Full article
Open AccessProceedings Microstructure for Thermal Impedance Spectroscopy for Biofuel Composition Measurement
Proceedings 2017, 1(4), 396; doi:10.3390/proceedings1040396
Published: 17 August 2017
PDF Full-text (699 KB)
Abstract
Thermal impedance spectroscopy has been investigated as a non-destructive technique to determine the composition of ternary mixtures of biofuels. The principle of the thermal conductivity detector has been extended for measuring both the thermal conductivity and the thermal capacity of biofuel in the
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Thermal impedance spectroscopy has been investigated as a non-destructive technique to determine the composition of ternary mixtures of biofuels. The principle of the thermal conductivity detector has been extended for measuring both the thermal conductivity and the thermal capacity of biofuel in the range between 1 to 100 Hz, using an AC-operated polysilicon heater for injecting a sinusoidal heat flux, and another polysilicon strip at a well-defined spacing or thermopile sensors for measuring the in-phase and quadrature components of the resulting AC temperature difference. Full article
Open AccessProceedings ZnO Nanostructure Based QCM Sensor to Detect Ethanol at Room Temperature Fabricated by All Wet Process
Proceedings 2017, 1(4), 397; doi:10.3390/proceedings1040397
Published: 8 August 2017
PDF Full-text (494 KB)
Abstract
QCM is one of major sensing methods for volatile organic compounds (VOC) at room temperature. Nanostructure is effective to increase the sensitivity because of its large surface area. We introduced ZnO nanostructure to detect ethanol gas. ZnO nanostructure was fabricated by all wet
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QCM is one of major sensing methods for volatile organic compounds (VOC) at room temperature. Nanostructure is effective to increase the sensitivity because of its large surface area. We introduced ZnO nanostructure to detect ethanol gas. ZnO nanostructure was fabricated by all wet process such as electrodeposition and chemical bath deposition (CBD). In this case, seed layer was obtained by electrodeposition, and nanostructure was formed by the CBD. The thickness of seed layer was controllable by charge amount on the electrodeposition, and that of nanostructure was controllable by deposition time on the CBD. As the results, the sensitivity increased with the thickness of the seed layer when the deposition time on CBD was set as 30 min. These results indicate that we can obtain high sensitive VOC sensor by using all wet process which is fit to large scale production with cost-effective. Full article
Open AccessProceedings Use of Gas Sensors and FOBT for the Early Detection of Colorectal Cancer
Proceedings 2017, 1(4), 398; doi:10.3390/proceedings1040398
Published: 31 August 2017
PDF Full-text (299 KB)
Abstract
Among the major challenges of medicine today there are screening and early detection of tumors (since the adenoma stage) in order to prevent their degeneration into malignant cancer and/or metastases. In particular, the colorectal cancer shows a high curability rate, up to 90%,
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Among the major challenges of medicine today there are screening and early detection of tumors (since the adenoma stage) in order to prevent their degeneration into malignant cancer and/or metastases. In particular, the colorectal cancer shows a high curability rate, up to 90%, if identified when in its benign stage. The Protocol discussed here is proposed to implement the clinical validation of a device consisting of an array of chemoresistive gas sensors made of semiconductor materials, able of identifying the difference between fecal exhalation of healthy subjects and of subjects suffering from high-risk colorectal polyps or tumors. The tests are compared to the results of fecal occult blood test and colonoscopy as a gold standard. Full article
Open AccessProceedings Sensitive and Selective Ammonia Gas Sensor Based on Molecularly Modified SnO2
Proceedings 2017, 1(4), 399; doi:10.3390/proceedings1040399
Published: 25 August 2017
PDF Full-text (552 KB)
Abstract
The development of selective and cheap metal oxide gas sensor at ambient temperature is still a challenging idea. In this study, SnO2 surface functionalization was performed in order to obtain sensitive and selective gas sensor operated at ambient temperature. 3-aminopropyltriethoxysilane (APTES) was
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The development of selective and cheap metal oxide gas sensor at ambient temperature is still a challenging idea. In this study, SnO2 surface functionalization was performed in order to obtain sensitive and selective gas sensor operated at ambient temperature. 3-aminopropyltriethoxysilane (APTES) was used as an intermediate step, followed by functionalization with molecules having acyl chloride with different end functional groups molecules such as alkyl, acid and ester groups. Acid and ester modified sensors are sensitive to ammonia between 0.2 and 10 ppm at room temperature. However, ester modified SnO2 is more selective than acid modified sensor regarding ethanol and carbon monoxide gases. Full article
Open AccessProceedings Reliable Long-Term Data from Low-Cost Gas Sensor Networks in the Environment
Proceedings 2017, 1(4), 400; doi:10.3390/proceedings1040400
Published: 25 August 2017
PDF Full-text (739 KB)
Abstract
This poster examines long-term performance of low-cost instruments in environmental networks using a semiconducting oxide sensor measuring ground-level ozone (O3). Sensors were placed outside in networks and automated methodologies based on knowledge of sensor and environment characteristics were successfully applied to
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This poster examines long-term performance of low-cost instruments in environmental networks using a semiconducting oxide sensor measuring ground-level ozone (O3). Sensors were placed outside in networks and automated methodologies based on knowledge of sensor and environment characteristics were successfully applied to confirm sensor stability. These networks demonstrated how environmental data could be collected and confirmed using networks of low-cost sensors, which supplemented observations from the existing regulatory network. This work is a critical step in the development of networks of low-cost environmental sensors when considering the delivery of reliable data. Full article
Open AccessProceedings Oxygen Sensors Based on Screen Printed Platinum and Palladium Doped Indium Oxides
Proceedings 2017, 1(4), 401; doi:10.3390/proceedings1040401
Published: 11 August 2017
PDF Full-text (1617 KB)
Abstract
Platinum and palladium doped indium oxide sensors have been successfully fabricated by a screen printing method and tested as oxygen sensors at low temperature (150–400 °C) in a humid environment (~80–85% RH). The sensors, complying with a power law relationship, showed good differentiation
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Platinum and palladium doped indium oxide sensors have been successfully fabricated by a screen printing method and tested as oxygen sensors at low temperature (150–400 °C) in a humid environment (~80–85% RH). The sensors, complying with a power law relationship, showed good differentiation at lower temperatures with highest response observed at 200 °C. Platinum had sensitivity of 2.2% per %O2 and power law exponent α = 0.72 vs. 0.3% per %O2 for palladium with power law exponent α = 0.51. Overall, the response of platinum doped indium oxide was higher than the palladium doped version. Full article
Open AccessProceedings Plasma Oxidized W-WOx Sensor for Sub-ppm H2S Detection
Proceedings 2017, 1(4), 402; doi:10.3390/proceedings1040402
Published: 29 August 2017
PDF Full-text (334 KB)
Abstract
In this work we have fabricated W-WOx core-shell nanowire structure using plasma oxidation, a CMOS compatible process, for sensing H2S gas. For comparison, the sputtered stack structure of W-WOx with different thickness ratios of W to WOx is
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In this work we have fabricated W-WOx core-shell nanowire structure using plasma oxidation, a CMOS compatible process, for sensing H2S gas. For comparison, the sputtered stack structure of W-WOx with different thickness ratios of W to WOx is fabricated and characterized for H2S sensing. The sensor fabricated using plasma oxidation process is found to be significantly better in sensing performance compared to the sensing results obtained from sensor fabricated using sputtering. The response of plasma oxidized sensor is 90.4% for 1 ppm H2S with response and recovery time of 4 s and 46 s respectively. In contrast, the sensor fabricated with sputtered film shows a response of 30.6% at 1 ppm with response and recovery times of 19 s and 84 s respectively. This study clearly indicates that plasma oxidation is an efficient method for development of stable sensors. Full article
Open AccessProceedings Sensitivity Improvement of Thermoelectric Hydrocarbon Sensors: Combination of Glass-Ceramic Tapes and Alumina Substrates
Proceedings 2017, 1(4), 403; doi:10.3390/proceedings1040403
Published: 7 August 2017
PDF Full-text (559 KB)
Abstract
This contribution presents the integration of glass-ceramic tapes on alumina substrates to increase the sensitivity of thermoelectric hydrocarbon gas sensors. Both ceramic materials have different thermal conductivity. Their combination into one sensor structure significantly improves the sensitivity by at the same time maintaining
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This contribution presents the integration of glass-ceramic tapes on alumina substrates to increase the sensitivity of thermoelectric hydrocarbon gas sensors. Both ceramic materials have different thermal conductivity. Their combination into one sensor structure significantly improves the sensitivity by at the same time maintaining the excellent mechanical stability at high temperatures. Furthermore, this special technology allows for an easy integration of additional functional elements such as screen-printed thermocouples for temperature control purposes. Full article
Open AccessProceedings Modification of SnO2 Nanowires with TeO2 Branches and Their Enhanced Gas Sensing
Proceedings 2017, 1(4), 404; doi:10.3390/proceedings1040404
Published: 17 August 2017
PDF Full-text (1735 KB)
Abstract
We prepared a highly sensitive and selective NO2 sensor, based on the TeO2 branched SnO2 nanowires (NWs), in terms of vapor-liquid-solid method, with subsequent growing of branches on the stems of SnO2 NWs. Fabricated sensors showed a high response
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We prepared a highly sensitive and selective NO2 sensor, based on the TeO2 branched SnO2 nanowires (NWs), in terms of vapor-liquid-solid method, with subsequent growing of branches on the stems of SnO2 NWs. Fabricated sensors showed a high response higher than 10 to 10 ppm of NO2 gas at 100 °C. We investigated the associated sensing mechanisms, with respect to the enhancement of sensing behaviors by the addition of TeO2 branches. Based on the results obtained in this work, we believe that the present sensor with an efficient fabrication technique, and high sensitivity and selectivity can be used for detection of NO2 gas in real applications. Full article
Open AccessProceedings Selective Detection of NO2 with Specific Filters for O3 Trapping
Proceedings 2017, 1(4), 405; doi:10.3390/proceedings1040405
Published: 28 August 2017
PDF Full-text (566 KB)
Abstract
The present study evaluates the ozone (O3) and nitrogen dioxide (NO2) removal performance of specific filters based on nanoporous materials. These materials, produced via the sol-gel process with functionalized silicon alkoxides as precursors, are tailored for O3 trapping.
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The present study evaluates the ozone (O3) and nitrogen dioxide (NO2) removal performance of specific filters based on nanoporous materials. These materials, produced via the sol-gel process with functionalized silicon alkoxides as precursors, are tailored for O3 trapping. The gas removal effectiveness of the filters was assessed through measurements of O3 concentrations in the air upstream and downstream of the filters. Depending on the filter nature, O3 can be totally trapped while NO2 can pass over a specific concentration range. Full article
Open AccessProceedings Enhance of Sensitivity of Corrole Functionalized Polymeric Microspheres Coated Quartz Microbalances
Proceedings 2017, 1(4), 406; doi:10.3390/proceedings1040406
Published: 17 August 2017
PDF Full-text (1520 KB)
Abstract
An innovative and efficient β-functionalization of [5,10,15-tris-(4-methylphenyl)corrolato]Cobalt derivatives introduced an acrolein substituent, which allowed the copolymerization with pure acrolein. The obtained hybrid microparticles have been used as sensing materials of quart microbalance gas sensors. The sensing properties have been tested by exposure to
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An innovative and efficient β-functionalization of [5,10,15-tris-(4-methylphenyl)corrolato]Cobalt derivatives introduced an acrolein substituent, which allowed the copolymerization with pure acrolein. The obtained hybrid microparticles have been used as sensing materials of quart microbalance gas sensors. The sensing properties have been tested by exposure to different volatile organic compounds chosen as model analytes. Results show an improved sensitivity of the hybrid microparticles respect to the individual constituents. Full article
Open AccessProceedings Hybrid and Bio Nanocomposites for Ultrasensitive Ammonia Sensors
Proceedings 2017, 1(4), 407; doi:10.3390/proceedings1040407
Published: 11 August 2017
PDF Full-text (564 KB)
Abstract
New organic electronic organic ammonia sensors based on hybrid nanocomposites polyaniline-titanium dioxide and on PANI/chitosan with high metrological performances were created. The physical and chemical properties of the nanocomposites were optimized to get a high sensitivity and very low detection threshold (in ppb
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New organic electronic organic ammonia sensors based on hybrid nanocomposites polyaniline-titanium dioxide and on PANI/chitosan with high metrological performances were created. The physical and chemical properties of the nanocomposites were optimized to get a high sensitivity and very low detection threshold (in ppb values). For hybrids, in the core shell form, the performances were analyzed by the synergetic effects of the constituents. For biopolymers it is possible to get high performances ammonia sensors using the way of green chemistry. In both cases the nanocomposites worked at room temperature and showed linear responses with a response time around one minute. Full article
Open AccessProceedings MgO-Doped (Zr,Sr)TiO3 Perovskite Humidity Sensors: Microstructural Effects on Water Permeation
Proceedings 2017, 1(4), 408; doi:10.3390/proceedings1040408
Published: 8 August 2017
PDF Full-text (989 KB)
Abstract
Porous (Zr0.5,Sr0.5)TiO3 and MgO (1, 3, 5 mol%) doped ZST nanocomposites have been developed and investigated as humidity sensing elements. The surface area analyser and FESEM data have indicated that the MgO doped perovskites are contained of the
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Porous (Zr0.5,Sr0.5)TiO3 and MgO (1, 3, 5 mol%) doped ZST nanocomposites have been developed and investigated as humidity sensing elements. The surface area analyser and FESEM data have indicated that the MgO doped perovskites are contained of the macropores and grain size of about 77 to 87 nm. EFTEM proved the reduction of particle size by addition of MgO dopant concentration. While pure ZST shows BET surface area of about 58 m2/g, MgO doped samples exhibit about 12 m2/g. Sensor contained of ZST doped with 3 mol% MgO shows highest sensitivity with about four orders of magnitude change in impedance within the range of 20% to 95% RH. Full article
Open AccessProceedings Effects of Infrared Energy on Dual Elliptical NDIR Ethanol Gas Sensors
Proceedings 2017, 1(4), 409; doi:10.3390/proceedings1040409
Published: 5 September 2017
PDF Full-text (620 KB)
Abstract
This paper presents the effects of infrared energies on dual elliptical nondispersive infrared (NDIR) ethanol gas sensors for preventing drunken drivers and the advantages of using dual ethanol detectors for temperature compensation algorithm. In order to achieve long-term reliability according to the aging
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This paper presents the effects of infrared energies on dual elliptical nondispersive infrared (NDIR) ethanol gas sensors for preventing drunken drivers and the advantages of using dual ethanol detectors for temperature compensation algorithm. In order to achieve long-term reliability according to the aging of infrared source, two ethanol detectors are placed at the two foci of ellipsoids and the averaged voltage ratios of two ethanol detectors are used to establish the compensation methods. Full article
Open AccessProceedings Enhanced Characteristics of Nondispersive Infrared CO2 Gas Sensor by Deposition of Hydrophobic Thin Film
Proceedings 2017, 1(4), 410; doi:10.3390/proceedings1040410
Published: 17 August 2017
PDF Full-text (1105 KB)
Abstract
This paper presents the NDIR CO2 gas sensor that has improved the sensitivity and also the accuracy by the deposition of thin hydrophobic film (Parylene-C film with 0.5 micrometer thick) onto the reflector surfaces of White-cell structure. After deposition of hydrophobic thin
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This paper presents the NDIR CO2 gas sensor that has improved the sensitivity and also the accuracy by the deposition of thin hydrophobic film (Parylene-C film with 0.5 micrometer thick) onto the reflector surfaces of White-cell structure. After deposition of hydrophobic thin film, the sensitivity of sensor has been increased with averaged 10% and the estimated errors were reduced within 13 ppm to 143 ppm from 254 K to 324 K temperature ranges and from 0 ppm to 5000 ppm CO2 concentrations. Full article
Open AccessProceedings Room Temperature NO2 Responses of Visible-Light Activated Nanosheet rGO@ZnO1−x Sensors
Proceedings 2017, 1(4), 411; doi:10.3390/proceedings1040411
Published: 23 August 2017
PDF Full-text (2792 KB)
Abstract
In this study, we use a facile hydrothermal method to synthesize rGO@ZnO1−x composites. The in-situ synthesized ZnO nanosheets are well attached on the rGO sheets, which prevent the aggregation and restacking of ZnO nanosheets, greatly increasing the specific surface area of the
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In this study, we use a facile hydrothermal method to synthesize rGO@ZnO1−x composites. The in-situ synthesized ZnO nanosheets are well attached on the rGO sheets, which prevent the aggregation and restacking of ZnO nanosheets, greatly increasing the specific surface area of the synthesized materials. In addition, on account of the reducing synthesis condition, large numbers of oxygen vacancies are implanted into ZnO. With the incorporation of rGO, the visible light absorption range of the composites is greatly enhanced. The synthesized rGO@ZnO1−x composites exhibit excellent performance to ppb-level NO2 under white light illumination at room temperature, which effectively overcomes the disadvantages of typical metal oxide gas sensors. Full article
Open AccessProceedings Light-Assisted Room-Temperature NO2 Sensors Based on Black Sheet-Like NiO
Proceedings 2017, 1(4), 412; doi:10.3390/proceedings1040412
Published: 22 August 2017
PDF Full-text (2777 KB)
Abstract
In this study, we use two-dimensional black flake nickel oxide as the sensitive material which was synthesized by a facile hydrothermal route. The as-synthesized sheet-like NiO possessed a large specific surface area, as verified by BET characterization. The as-prepared NiO nanosheets had strong
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In this study, we use two-dimensional black flake nickel oxide as the sensitive material which was synthesized by a facile hydrothermal route. The as-synthesized sheet-like NiO possessed a large specific surface area, as verified by BET characterization. The as-prepared NiO nanosheets had strong absorption in the range of 250–800 nm including UV and visible light. Upon exposure to ppb-level NO2, the presented sensors showed significant responses under light illumination at room temperature. In addition, the light wavelength also had a remarkable effect on the sensing performance in terms of sensitivity, response and recovery kinetics. Furthermore, the sensor showed a low humidity dependence. Full article
Open AccessProceedings Improving the Performance of Electrochemical Sensors by Means of Synergy. Combinations of Gold Nanoparticles and Phthalocyanines
Proceedings 2017, 1(4), 413; doi:10.3390/proceedings1040413
Published: 22 August 2017
PDF Full-text (355 KB)
Abstract
Voltammetric sensors chemically modified with combinations of two electrocatalytic materials: tetraoctylammonium bromide capped gold nanoparticles (AuNPNBr) and a sulphur containing zinc phthalocyanine derivative (ZnPcRS) are reported. The electrocatalytic effects in the detection of catechol have been analyzed in sensors
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Voltammetric sensors chemically modified with combinations of two electrocatalytic materials: tetraoctylammonium bromide capped gold nanoparticles (AuNPNBr) and a sulphur containing zinc phthalocyanine derivative (ZnPcRS) are reported. The electrocatalytic effects in the detection of catechol have been analyzed in sensors obtained by direct mixing (AuNPNBr/ZnPcRS) and in sensors modified with an adduct where both components are linked covalently (AuNPNBr-S-ZnPcR). Results demonstrate that the nature of the interaction between both components modifies the electrocatalytic properties. The AuNPNBr/ZnPcRS mixture improves the electron transfer rate of the catechol reduction, with limits of detection of 10−6 M. The covalent adduct AuNPNBr-S-ZnPcR enhances the response rate of the oxidation of the catechol with limits of detection of 10−7 M. Full article
Open AccessProceedings Planar Microstrip Ring Resonator Structure for Gas Sensing and Humidity Sensing Purposes
Proceedings 2017, 1(4), 414; doi:10.3390/proceedings1040414
Published: 21 August 2017
PDF Full-text (613 KB)
Abstract
A planar microstrip ring resonator structure on alumina was developed. It was covered with a zeolite film. The device was successfully operated at around 8.5 GHz at room temperature as a humidity sensor. In the next step, an additional planar heater will be
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A planar microstrip ring resonator structure on alumina was developed. It was covered with a zeolite film. The device was successfully operated at around 8.5 GHz at room temperature as a humidity sensor. In the next step, an additional planar heater will be included on the reverse side of the resonator structure to allow for testing of gas sensitive materials under sensor conditions. Full article
Open AccessProceedings Lipophilic Gold Grating for SERS Detection of Biological Objects
Proceedings 2017, 1(4), 415; doi:10.3390/proceedings1040415
Published: 4 August 2017
PDF Full-text (1424 KB)
Abstract
We introduce label-free plasmon-active platform based on ordered gold gratings with the covalently modified surface for detection of lipophilic bioobjects. Alkylbenzene groups with different chain length (CH3-, C4H9-, C10H21- and C16H33)
[...] Read more.
We introduce label-free plasmon-active platform based on ordered gold gratings with the covalently modified surface for detection of lipophilic bioobjects. Alkylbenzene groups with different chain length (CH3-, C4H9-, C10H21- and C16H33) were grafted spontaneously and electrochemically for improvement of affinity with lipophilic compounds. Modified grating surfaces were characterized by XPS, CVA, wettability, AFM and Raman spectroscopy techniques. Full article
Open AccessProceedings NAP-XPS Study of Ethanol Adsorption on TiO2 Surfaces and Its Impact on Microwave-Based Gas Sensors Response
Proceedings 2017, 1(4), 416; doi:10.3390/proceedings1040416
Published: 18 August 2017
PDF Full-text (483 KB)
Abstract
This work presents new elements of understanding for the microwave-based gas sensors behavior at room temperature. A TiO2-covered microstrip interdigital capacitor was submitted to various ethanol concentrations and showed a proportional response in the 1–10 GHz microwave range. For each concentration
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This work presents new elements of understanding for the microwave-based gas sensors behavior at room temperature. A TiO2-covered microstrip interdigital capacitor was submitted to various ethanol concentrations and showed a proportional response in the 1–10 GHz microwave range. For each concentration and right after ethanol injection, the sensor response presented a slight overshoot which is often found in gas sensors studies. Near ambient pressure photoemission experiments (NAP-XPS) were conducted to explore the physicochemical causes of this overshoot, and demonstrated the formation of an ethoxide during ethanol adsorption. Full article
Open AccessProceedings Tuning of the Humidity-Interference in Gas Sensitive Columnar ZnO Structures
Proceedings 2017, 1(4), 417; doi:10.3390/proceedings1040417
Published: 23 August 2017
Cited by 1 | PDF Full-text (1061 KB)
Abstract
Gas microsensors based on columnar zinc oxide structures (rods and needles) with different aspect ratios and wetting properties are developed via aerosol-assisted chemical vapor deposition. The correlation between their wetting properties and degree of humidity-interference in gas sensing is presented. Gas sensing tests
[...] Read more.
Gas microsensors based on columnar zinc oxide structures (rods and needles) with different aspect ratios and wetting properties are developed via aerosol-assisted chemical vapor deposition. The correlation between their wetting properties and degree of humidity-interference in gas sensing is presented. Gas sensing tests of these systems to hydrogen demonstrate noticeable lower humidity-interference for the columnar zinc oxide structures in the form of needles provided of higher hydrophobicity, as opposed to those in the form of rods, suggesting that a tuning of the wetting properties in metal oxides could allow for the humidity-resilient detection of gaseous analytes. Full article
Open AccessProceedings ZnO/SnO2 Heterojunctions Sensors with UV-Enhanced Gas-Sensing Properties at Room Temperature
Proceedings 2017, 1(4), 418; doi:10.3390/proceedings1040418
Published: 11 August 2017
PDF Full-text (572 KB)
Abstract
We report herein the efficiency of microwave-assisted synthesis for obtaining ZnO/SnO2 heterostructures for room-temperature gas-sensing applications. The sensing performances of the traditional oxide materials have been found for applications above 200 °C. However, these temperatures were here reduced to room temperature by
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We report herein the efficiency of microwave-assisted synthesis for obtaining ZnO/SnO2 heterostructures for room-temperature gas-sensing applications. The sensing performances of the traditional oxide materials have been found for applications above 200 °C. However, these temperatures were here reduced to room temperature by considering sensing activity photoactivated by UV light, even for ppb ozone (O3) levels. The heterojunctions exhibited a fast response, total reversibility, and selectivity to oxidizing gases, especially O3 gas. This investigation provides an efficient way to obtain heterostructures exhibiting remarkable properties for practical applications as O3 gas sensor devices. Full article
Open AccessProceedings Development of All-Around SiO2/Al2O3 Gate, Suspended Silicon Nanowire Chemical Field Effect Transistors Si-nw-ChemFET
Proceedings 2017, 1(4), 419; doi:10.3390/proceedings1040419
Published: 8 August 2017
PDF Full-text (378 KB)
Abstract
We present a sensor platform associated to silicon-nanowire chemical field effect transistors (Si-nw-ChemFET). Innovations concern the use of networks of suspended silicon N+/P/N+ nanowires as conducting channel, the realization by thermal oxidation and Atomic-Layer Deposition (ALD) of a SiO2
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We present a sensor platform associated to silicon-nanowire chemical field effect transistors (Si-nw-ChemFET). Innovations concern the use of networks of suspended silicon N+/P/N+ nanowires as conducting channel, the realization by thermal oxidation and Atomic-Layer Deposition (ALD) of a SiO2/Al2O3 gate insulator all-around the silicon nanowires, and their final integration into covered SU8-based microfluidic channels. The Si-nw-MOSFET/ChemFET fabrication process and electrical/electrochemical characterizations are presented. The fabrication process did not need an expensive and time-consuming e-beam lithography, but only fast and “low cost” standard photolithography protocols. Such microdevice will provide new opportunities for bio-chemical analysis at the micro/nanoscale. Full article
Open AccessProceedings Multimodal Probe Based on ISFET Electrochemical Microsensors for In-Situ Monitoring of Soil Nutrients in Agriculture
Proceedings 2017, 1(4), 420; doi:10.3390/proceedings1040420
Published: 17 August 2017
PDF Full-text (573 KB)
Abstract
We report the design of a silicon chip dedicated to the in-situ monitoring of soil nitrogen cycle in wheat crop. Our study shows that ion-sensitive field effect transistor (ISFET) microsensors are suitable for quick on-site or long-term analysis of nutrients measured directly in
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We report the design of a silicon chip dedicated to the in-situ monitoring of soil nitrogen cycle in wheat crop. Our study shows that ion-sensitive field effect transistor (ISFET) microsensors are suitable for quick on-site or long-term analysis of nutrients measured directly in soil as opposed to soil extracts analysis. Our pH-ISFET recorded soil pH for six months with results in good accordance with standard sampling method and without any loss of sensitivity. The adaptation of pH-ISFET in pNO3 and pNH4-ISFET allowed, for the first time, the in-situ measurements of natural variations of soil nitrogen contents caused by microorganisms’ activity Full article
Open AccessProceedings High Bandwidth Sensor Module for Mobile Robot Applications-Wind Tunnel Characterization
Proceedings 2017, 1(4), 421; doi:10.3390/proceedings1040421
Published: 25 August 2017
PDF Full-text (2553 KB)
Abstract
We have developed a sensor module containing high-bandwidth VOC and gas sensors (including novel acoustic, custom MOX and low-cost NDIR) to evaluate the concentration of gases in a hazardous environment. We report upon the initial characterization of two MOX gas sensors (1 mm
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We have developed a sensor module containing high-bandwidth VOC and gas sensors (including novel acoustic, custom MOX and low-cost NDIR) to evaluate the concentration of gases in a hazardous environment. We report upon the initial characterization of two MOX gas sensors (1 mm × 1 mm) with coatings of Pd/Pt doped SnO2 and pure WO3 inside a wind tunnel to plumes of acetone and ethanol (<10 ppm). The orientation and position of the sensor module in the tunnel was investigated. The unit was tested in a real-world environment with a VOC (propanol); fluctuating sensor responses demonstrated the formation of gas plumes. Full article
Open AccessProceedings Method for Determining the Concentration of Unknown Combustible Gas
Proceedings 2017, 1(4), 422; doi:10.3390/proceedings1040422
Published: 9 August 2017
PDF Full-text (441 KB)
Abstract
It is known that catalytic sensors have different sensitivities to different combustible gases. Usually gas analyzers are calibrated by methane and not suitable for measuring other flammable gases. Correction is needed to get real concentration of other gases. In this paper it is
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It is known that catalytic sensors have different sensitivities to different combustible gases. Usually gas analyzers are calibrated by methane and not suitable for measuring other flammable gases. Correction is needed to get real concentration of other gases. In this paper it is shown that sensor sensitivity to one particular gas alters with sensor temperature and each gas has its own rate of reducing the sensitivity with a further increase of temperature. It allows us to calculate the concentration of unknown flammable gas. Applying this method decreases measurement error from 30–40% to 5–10% for hydrocarbons. Full article
Open AccessProceedings Ozone Sensors Working at Room Temperature Using Zinc Oxide Nanocrystals Annealed at Low Temperature
Proceedings 2017, 1(4), 423; doi:10.3390/proceedings1040423
Published: 11 August 2017
PDF Full-text (563 KB)
Abstract
We focus on ozone (O3) detection at ambient temperature by Zinc Oxide (ZnO) nanoparticles (NPs) deposited on Si/SiO2 by spin coating from colloidal solutions as sensitive layers for air quality monitoring. We establish that at room temperature using continuous Ultra-Violet
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We focus on ozone (O3) detection at ambient temperature by Zinc Oxide (ZnO) nanoparticles (NPs) deposited on Si/SiO2 by spin coating from colloidal solutions as sensitive layers for air quality monitoring. We establish that at room temperature using continuous Ultra-Violet (UV) light irradiation enhances the sensing responses. Three annealing temperatures of ZnO films were performed to compare the sensing properties. These sensors present repeatable responses towards O3 with fast responses for concentrations as low as 35 ppb with processes compatible with most of flexible substrates. Full article
Open AccessProceedings Direct Catalyst Conversion Sensor in Form of a Single Self-Heated Mixed-Potential Device
Proceedings 2017, 1(4), 424; doi:10.3390/proceedings1040424
Published: 7 August 2017
PDF Full-text (428 KB)
Abstract
Monitoring automotive exhaust gas aftertreatment components is required by law as part of the on-board diagnostics (OBD). For this purpose, a novel sensor device that determines directly the catalyst conversion could be used. It consists of a single, self-heated yttria stabilized ZrO2
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Monitoring automotive exhaust gas aftertreatment components is required by law as part of the on-board diagnostics (OBD). For this purpose, a novel sensor device that determines directly the catalyst conversion could be used. It consists of a single, self-heated yttria stabilized ZrO2-based disc, separating two gas atmospheres. Two identical mixed-potential electrodes yield a voltage signal by comparing a certain trace gas concentration up- and downstream of the catalyst. Measurements in synthetic gas flow verify the theoretical assumption that this voltage signal only depends on the ratio of both concentrations, respectively on the conversion of the catalyst. Full article
Open AccessProceedings Performance Evaluation of Low-Cost BTEX Sensors and Devices within the EURAMET Key-VOCs Project
Proceedings 2017, 1(4), 425; doi:10.3390/proceedings1040425
Published: 29 August 2017
PDF Full-text (422 KB)
Abstract
The KEY-VOCs project is a EURAMET joint research project focused on key Volatile Organic Compounds (VOCs) in air. One of its activities is the evaluation of sensors-based measurement systems. In Europe, the monitoring of benzene in ambient air is mandatory as set by
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The KEY-VOCs project is a EURAMET joint research project focused on key Volatile Organic Compounds (VOCs) in air. One of its activities is the evaluation of sensors-based measurement systems. In Europe, the monitoring of benzene in ambient air is mandatory as set by the European Directive for air quality (AQD) [1]. This Directive states that the reference method of measurement shall consist of active or on-line sampling followed by gas chromatography [2]. These methods are time consuming, expensive to implement and not easily portable prohibiting more local estimation of the population exposure. However, the AQD allows using indicative measurements with higher uncertainty than those of the reference methods. Sensor systems are good candidates for indicative methods with the additional ability of near-to real-time measurements. Full article
Open AccessProceedings A Non Invasive Sensor System for the Screening of Obstructive Sleep Apnea Syndrome
Proceedings 2017, 1(4), 426; doi:10.3390/proceedings1040426
Published: 7 August 2017
PDF Full-text (500 KB)
Abstract
Obstructive Sleep Apnea Syndrome (OSAS) diagnosis can be confirmed only after the polysomnography (PSG), a non-invasive examination requiring one-night hospitalization. Moreover, up to 45% of people undergone PSG actually are free from OSAS. A non invasive sensor system collecting exhaled breath and giving
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Obstructive Sleep Apnea Syndrome (OSAS) diagnosis can be confirmed only after the polysomnography (PSG), a non-invasive examination requiring one-night hospitalization. Moreover, up to 45% of people undergone PSG actually are free from OSAS. A non invasive sensor system collecting exhaled breath and giving a fingerprint of its composition should be a valuable mean for the selection of patients amenable to polysomnography (PSG). Here the BIONOTE (a gas sensor array based on Quartz micro balances functionalized with anthocyanins) together with the Pneumopipe (a patented device for exhaled breath collection) have been used in a study including 136 subjects. BIONOTE was able to correctly discriminate controls with respect to diseased individuals and Chronic Obstructive Pulmonary Diseased (COPD) against OSAS patients. Full article
Open AccessProceedings Interaction of Colloidal Silver Nanoparticles with Ni2+: Sensing Application
Proceedings 2017, 1(4), 427; doi:10.3390/proceedings1040427
Published: 18 August 2017
PDF Full-text (256 KB)
Abstract
We report on synthesis of silver nanoparticles (AgNPs) capped with specific thiol suitable to detect heavy metal ions in water. The sensing mechanism is based on a change of an optical properties of the silver colloids, namely the surface plasmon resonance (SPR) when
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We report on synthesis of silver nanoparticles (AgNPs) capped with specific thiol suitable to detect heavy metal ions in water. The sensing mechanism is based on a change of an optical properties of the silver colloids, namely the surface plasmon resonance (SPR) when small amounts of contaminants are present in solution. We detected a specific sensitivity to nickel ions and we investigated the interaction of the AgNPs with Ni2+ in the concentration range of 0.5–2.0 ppm. Full article
Open AccessProceedings WO3-Doped Indium Oxide Thick Films for Ozone Detection at Low Temperature
Proceedings 2017, 1(4), 428; doi:10.3390/proceedings1040428
Published: 18 August 2017
PDF Full-text (829 KB)
Abstract
Ozone, a strong oxidizing gas, has dramatically increased its concentration in the troposphere during the last decades. Since high O3 concentrations are hazardous to human health, the development of effective methods and economic devices to detect this gas is an urgent need.
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Ozone, a strong oxidizing gas, has dramatically increased its concentration in the troposphere during the last decades. Since high O3 concentrations are hazardous to human health, the development of effective methods and economic devices to detect this gas is an urgent need. In this frame, In2O3 is well known as an n-type ozone sensitive and selective material, generally displaying its optimal sensing capability in the temperature range 200–350 °C. To enhance the sensing capability of In2O3 and to decrease its operative temperature, in this work, commercial In2O3 powders were doped with 2.5 wt. % WO3. Pure and doped-In2O3 materials were used to develop sensing devices by screen-printing technology. Resistance measurements were performed in the temperature range 25 °C–150 °C under 200–500 ppb O3. Best results were obtained at 75 °C with sensor’s responses as high as 40 under 200 ppb of ozone.
Full article
Open AccessProceedings Deposition Rate Influence in O3 Sensing Response of Sputtered ZnO Thin Films
Proceedings 2017, 1(4), 429; doi:10.3390/proceedings1040429
Published: 30 August 2017
PDF Full-text (2154 KB)
Abstract
The study of semiconductor materials applied as chemical gas sensing devices is currently focused on the production of new sensing materials with the best possible properties in terms of detection limits, selectivity, work temperature and response time. Although theoretical models show the great
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The study of semiconductor materials applied as chemical gas sensing devices is currently focused on the production of new sensing materials with the best possible properties in terms of detection limits, selectivity, work temperature and response time. Although theoretical models show the great importance of film morphology on gas detection, a direct relation between structure size/morphology and the gas sensing properties has not been experimentally established. In this work, RF-sputtering deposition technique was used for the synthesis of zinc oxide thin films, and deposition conditions are variated to achieve a remarkable difference in nanostructure size of the material. The electrical resistance variation of the air-exposed films in presence of different ozone concentrations show a strong dependence on the feature size and film morphology, demonstrating the effectiveness of use the parameters of RF sputtering deposition as tunable factors to improve the ZnO sensing properties. Full article
Open AccessProceedings A Textile Based Polypyrrole Chloride Sensor for Agricultural Use
Proceedings 2017, 1(4), 430; doi:10.3390/proceedings1040430
Published: 9 August 2017
PDF Full-text (534 KB)
Abstract
This paper describes the feasibility of developing a novel polypyrrole (PPy) potentiometric sensor. Conductive PPy-based polymers has been grown through a textile scaffold to create a flexible and robust sensing structure that can survive environments such as soil, with the choice of the
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This paper describes the feasibility of developing a novel polypyrrole (PPy) potentiometric sensor. Conductive PPy-based polymers has been grown through a textile scaffold to create a flexible and robust sensing structure that can survive environments such as soil, with the choice of the scaffold materials offering control of the environmental impact. Further work has demonstrated that doped PPy has an electrochemical response that is sensitive to different measurands’ concentration and in this case, we look at chloride response. Various chloride sensors were evaluated in varying concentrations of the potassium chloride test solutions in terms of their chloride ion sensitivity, hydration times and usable lifetime. The best performing sensor has shown a near-Nernstian response between 45–48 mV/decade to chloride ions and at least 2 weeks initial lifetime. Full article
Open AccessProceedings Transdermal Alcohol Measurements Using MOX Sensors in Clinical Trials
Proceedings 2017, 1(4), 431; doi:10.3390/proceedings1040431
Published: 11 August 2017
PDF Full-text (1441 KB)
Abstract
Human metabolism often results in the emission of many VOCs through the skin. Ethanol is one of volatile compounds which are evaporated by perspiration. The aim of our research consists to develop chemical sensors for monitoring ethanol emission after alcohol consumption. The interest
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Human metabolism often results in the emission of many VOCs through the skin. Ethanol is one of volatile compounds which are evaporated by perspiration. The aim of our research consists to develop chemical sensors for monitoring ethanol emission after alcohol consumption. The interest of using chemical sensors is noninvasive measurement and controlling alcohol level in the human body and to make the link between these measurements and that in the blood or in the breath. Recent clinical trials demonstrated the feasibility and relevance of this measurement method. Metal oxide sensors were calibrated in respect of the thermodynamic conditions of the surface of the skin. In this paper we show the first sensor responses by perspiration. Full article
Open AccessProceedings Operando Investigations of Differently Prepared In2O3-Gas Sensors
Proceedings 2017, 1(4), 432; doi:10.3390/proceedings1040432
Published: 29 August 2017
Cited by 1 | PDF Full-text (286 KB)
Abstract
In this study, the electrical characteristics and surface reactions of three different kinds of In2O3 based gas sensors were investigated under CO exposure in dry and humid air by using DC electrical resistance measurements and Diffuse reflectance infrared Fourier transform
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In this study, the electrical characteristics and surface reactions of three different kinds of In2O3 based gas sensors were investigated under CO exposure in dry and humid air by using DC electrical resistance measurements and Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). For the first time one gains insight into the surface reactions during the exposure to CO and humidity. The sensors show different behavior on the baseline in humidity depending on the material which is due to different kinds of OH-groups. The resistance change under CO and humidity exposure are additive and the molecules compete for the same reaction partner confirmed by the spectroscopy results. Through isotopic exchange experiments, different adsorbates could be identified. Full article
Open AccessProceedings Picomolar Detection of Heavy Ions with Surface Acoustic Wave Sensors Functionalized with New Synthetized Anthracene Derivates
Proceedings 2017, 1(4), 433; doi:10.3390/proceedings1040433
Published: 7 August 2017
PDF Full-text (513 KB)
Abstract
104 MHz-surface acoustic wave sensors have been functionalized with three new anthracenederivatives for the detection of mercury and copper heavy ions: 2,2-bis(4 anthracenylme,thoxy-1,1′-biphenyl(BP-AN), 9-{[4-({[4-(9anthrylmethoxy)phenyl]sulfanyl}methyl)]methyl] anthracene (TDP-AN) and 4-(9-anthrylmethoxy) benzyl [4-(9-anthrylmethoxy) phenyl] sulfone (BPS-AN). Gravimetric results indicate that, compared to TDP-AN and BPS-AN, BP-AN
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104 MHz-surface acoustic wave sensors have been functionalized with three new anthracenederivatives for the detection of mercury and copper heavy ions: 2,2-bis(4 anthracenylme,thoxy-1,1′-biphenyl(BP-AN), 9-{[4-({[4-(9anthrylmethoxy)phenyl]sulfanyl}methyl)]methyl] anthracene (TDP-AN) and 4-(9-anthrylmethoxy) benzyl [4-(9-anthrylmethoxy) phenyl] sulfone (BPS-AN). Gravimetric results indicate that, compared to TDP-AN and BPS-AN, BP-AN based chemsensor has the highest affinitytowards the two investigated ions.The corresponding sensitivities were of order of 3.67 × 108 °/M and 2.24 × 108 °/M for Hg2+ and Cu2+ respectively. The limit of detection of the BP-AN-SAW chemsensor, of order of 1 pM, is one of the lowest values ever reported in the literature. Experimental results were supported by quantum chemical calculations, based on the density functional theory. Full article
Open AccessProceedings Acetone Detection by Chemical Sensors Based on Tungsten and Titanium Oxide Nanowires
Proceedings 2017, 1(4), 434; doi:10.3390/proceedings1040434
Published: 21 August 2017
PDF Full-text (1062 KB)
Abstract
Tungsten and titanium oxide (WO3/Ti) nanowires (NWs) were grown by thermal oxidation of a tungsten and titanium alloy (WTi) metallic layer deposited on 2 × 2 mm2 alumina substrates by DC magnetron sputtering. Thermal oxidation was carried out in a
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Tungsten and titanium oxide (WO3/Ti) nanowires (NWs) were grown by thermal oxidation of a tungsten and titanium alloy (WTi) metallic layer deposited on 2 × 2 mm2 alumina substrates by DC magnetron sputtering. Thermal oxidation was carried out in a custom evaporator chamber. Several parameters were controlled to achieve the optimal growth conditions. Morphological and structural analysis were performed on samples by a scanning electron microscope (SEM) and RAMAN spectroscopy, respectively. Nanowires, grown directly on the final transducer, were tested towards different gaseous species in a wide range of working temperatures. In this work, results obtained in presence of acetone are proposed. Full article
Open AccessProceedings Impedimetric Biosensor to Enable Fast Evaluation of Gaseous Sterilization Processes
Proceedings 2017, 1(4), 435; doi:10.3390/proceedings1040435
Published: 8 August 2017
PDF Full-text (2462 KB)
Abstract
Sterilization of packages prior to product filling is a key step in aseptic filling machines. Chemical sterilization is one of the main conventional techniques in many packaging industries. To monitor the effect of sterilization on test microorganisms (Bacillus atrophaeus spores), an impedimetric
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Sterilization of packages prior to product filling is a key step in aseptic filling machines. Chemical sterilization is one of the main conventional techniques in many packaging industries. To monitor the effect of sterilization on test microorganisms (Bacillus atrophaeus spores), an impedimetric sensor approach was developed based on a planar interdigitated electrode (IDE) design. In this work, sensor measurements were conducted to prove sensor functionality at different hydrogen peroxide concentrations. Full article
Open AccessProceedings Investigation of Behavior Stability of Activated Polyaniline Films for Gas Measurements
Proceedings 2017, 1(4), 436; doi:10.3390/proceedings1040436
Published: 8 August 2017
PDF Full-text (357 KB)
Abstract
Synthesis conditions of doped polyaniline films and testing procedure affect markedly the sensor behavior and stability of them. The sensor based on such film consists of a dielectric substrate with system of metallic interdigitated electrodes on its surface. The films were deposited on
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Synthesis conditions of doped polyaniline films and testing procedure affect markedly the sensor behavior and stability of them. The sensor based on such film consists of a dielectric substrate with system of metallic interdigitated electrodes on its surface. The films were deposited on system of metallic interdigitated electrodes by electrochemical synthesis from solutions of aniline with different polyoxometalates and acids. Activating additives into films were tungsten containing polyoxometalates of the eighteen series. Polyoxometalates as multielectron oxidants can alter noticeably the sensor properties of polyaniline if introduced into a conductive polymer film. Morphology of the layers surface and the infrared spectra were explored. Investigations of the behavior of polyoxometalate-polyaniline films at different temperatures, air humidity and testing procedures in clean air and in air containing ammonia were fulfilled. Full article
Open AccessProceedings Gas Sensing Approaches Based on WO3 Nanowire-Back Gated Devices
Proceedings 2017, 1(4), 437; doi:10.3390/proceedings1040437
Published: 9 August 2017
PDF Full-text (775 KB)
Abstract
This paper present a new design and configuration of metal oxide gas sensor based on back-gated device that can operate at low temperature. Gold electrodes patterned onto an oxidized, heavily doped, p-type silicon substrate were designed and fabricated at a wafer level.
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This paper present a new design and configuration of metal oxide gas sensor based on back-gated device that can operate at low temperature. Gold electrodes patterned onto an oxidized, heavily doped, p-type silicon substrate were designed and fabricated at a wafer level. The Au—electrodes were used as source—drain metal contacts and a third gate electrode was connected from the backside of the substrate. Tungsten oxide nanowires decorated with Pt-nanoparticles were directly grown employing aerosol assisted-CVD (AA-CVD) on top of the electrode area. Gas sensing properties of the back-gated device in the presence of air and hydrogen gas reveals characteristic response modulated by the applied gate potential at room temperature. It was found that the IDS-VGS plot illustrates characteristic field effect transistor with an inherent adsorptive surface electron transfer of the nanowires accompanied with the applied gate potential induced charge transfer. These counter-acting mechanisms might persuade for the application of back-gated device as a promising n-channel metal oxide gas sensor operating at low temperature or even room temperature. Full article
Open AccessProceedings Cobalt or Silver Doped WO3 Nanowires Deposited by a Two-Step AACVD for Gas Sensing Applications
Proceedings 2017, 1(4), 438; doi:10.3390/proceedings1040438
Published: 18 August 2017
PDF Full-text (461 KB)
Abstract
A two-step procedure was implemented to obtain tungsten oxide nanowires (WO3) doped with cobalt or silver oxide nanoparticles from metal-organic precursors, W(CO)6, Co(acac)2 and Ag(acac)2. In the first step, nanowires were grown at 400 °C using
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A two-step procedure was implemented to obtain tungsten oxide nanowires (WO3) doped with cobalt or silver oxide nanoparticles from metal-organic precursors, W(CO)6, Co(acac)2 and Ag(acac)2. In the first step, nanowires were grown at 400 °C using an aerosol assisted chemical vapor deposition system (AA-CVD) and subsequently annealed at 500 °C for 2 h. In the second step, metal loading (at different doping levels) of the nanowires using the same system. These hybrid nanomaterials were grown on top of commercial alumina substrates that comprised interdigitated electrodes. The response of these nanomaterials toward H2S and H2 is investigated and discussed. Full article
Open AccessProceedings Chemical Gas Sensor Based on a Flexible Capacitive Microwave Transducer Associated with a Sensitive Carbon Composite Polymer Film
Proceedings 2017, 1(4), 439; doi:10.3390/proceedings1040439
Published: 18 August 2017
PDF Full-text (1224 KB)
Abstract
This communication presents results on the feasibility of an inkjet printed chemical gas sensor suitable for a real time multi-sensing platform. The prototype targets volatile organic compounds (VOCs) such as ethanol vapor to monitor environmental pollution. The designed and ink-jet printed microwave sensor
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This communication presents results on the feasibility of an inkjet printed chemical gas sensor suitable for a real time multi-sensing platform. The prototype targets volatile organic compounds (VOCs) such as ethanol vapor to monitor environmental pollution. The designed and ink-jet printed microwave sensor is presented. Preliminary results have shown the influence of ethanol vapor on the electrical properties of the sensor at microwave frequency range. The sensor’s sensitivity to ethanol vapor has been estimated to −2.48 kHz/ppm. The final aim of this work is to develop a low cost sensor for Internet of Things (IoT) applications. Full article
Open AccessProceedings Detection of Mercury Vapor in Air by Differential Heat Dissipation Measurements
Proceedings 2017, 1(4), 440; doi:10.3390/proceedings1040440
Published: 16 August 2017
PDF Full-text (1597 KB)
Abstract
In this work, a novel approach for the detection of mercury vapor in air is presented using differential heat dissipation measurements. Therefore, the temperature difference between an amalgamated and a non-exposed gold film is recorded, while heating both films with identical electrical power.
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In this work, a novel approach for the detection of mercury vapor in air is presented using differential heat dissipation measurements. Therefore, the temperature difference between an amalgamated and a non-exposed gold film is recorded, while heating both films with identical electrical power. As the amalgam layer lowers the heat dissipation, the amalgamated gold film reaches higher temperatures compared to the non-exposed gold film. Preliminary experiments show a clear dependence of the measured temperature difference on the mercury vapor concentration and the exposition time. Thus, a detection of mercury vapor is generally possible using differential heat dissipation measurements. Full article
Open AccessProceedings Submersible Dielectric Probe for In Situ Monitoring of Suspensions and Its Application to Activated Sludge in Waste Water Treatment Plant
Proceedings 2017, 1(4), 441; doi:10.3390/proceedings1040441
Published: 8 August 2017
PDF Full-text (663 KB)
Abstract
We have developed a useful dielectric probe that allows real-time and in situ characterization of suspensions in the 0.4 to 10 MHz frequency range. It has been successfully tested throughout several weeks to monitor activated sludge of a waste water treatment plant. In
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We have developed a useful dielectric probe that allows real-time and in situ characterization of suspensions in the 0.4 to 10 MHz frequency range. It has been successfully tested throughout several weeks to monitor activated sludge of a waste water treatment plant. In this paper the results are compared with those obtained in parallel using both static or flow classic dielectric cells. Full article
Open AccessProceedings Tin Dioxide-Graphene Based Chemi-Device for NO2 Detection in the Sub ppm Range
Proceedings 2017, 1(4), 442; doi:10.3390/proceedings1040442
Published: 8 August 2017
PDF Full-text (972 KB)
Abstract
Chemical nanodevices based on tin dioxide, graphene and a mixture of both materials were developed and characterized for NO2 detection at low concentrations. The chemiresistors were prepared by both electrospinning and drop casting. The films morphologies were investigated by scanning electron microscopy
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Chemical nanodevices based on tin dioxide, graphene and a mixture of both materials were developed and characterized for NO2 detection at low concentrations. The chemiresistors were prepared by both electrospinning and drop casting. The films morphologies were investigated by scanning electron microscopy (SEM). The devices response to sub-ppm NO2 concentrations was measured from room temperature up to 300 °C. An improvement in the performance in terms of sensitivity and response time, as well as higher responses at room temperature, was obtained when a mixture of these materials is used. Full article
Open AccessProceedings Electron Capture Detector with Non-Radioactive Electron Source
Proceedings 2017, 1(4), 443; doi:10.3390/proceedings1040443
Published: 16 August 2017
PDF Full-text (882 KB)
Abstract
Gas chromatographs equipped with electron capture detectors (ECD) are widely used for the analysis of electron affine substances. Achieving limits of detection in the low pptv-range, electron capture detectors are the most sensitive detectors available for such compounds. Based on their
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Gas chromatographs equipped with electron capture detectors (ECD) are widely used for the analysis of electron affine substances. Achieving limits of detection in the low pptv-range, electron capture detectors are the most sensitive detectors available for such compounds. Based on their operating principle, they require free electrons at atmospheric pressure, which are usually generated by using a β--decay. However, the use of radioactive materials leads to regulatory restrictions regarding purchase, operation and disposal. Here, we present a new electron capture detector using a non-radioactive electron source, which is not subject to these limitations and offers further advantages such as adjustable and higher electron densities and energies. Full article
Open AccessProceedings Surface Acoustic Wave Sensors for the Detection of Hazardous Compounds in Indoor Air
Proceedings 2017, 1(4), 444; doi:10.3390/proceedings1040444
Published: 24 August 2017
PDF Full-text (592 KB)
Abstract
In this work, the authors show the capabilities of Surface Acoustic Wave (SAW) devices coupled with various absorbents to probe the properties of gas sensitive materials for the manufacturing of hazardous gas sensors. The great capabilities of cobalt corroles for the trapping of
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In this work, the authors show the capabilities of Surface Acoustic Wave (SAW) devices coupled with various absorbents to probe the properties of gas sensitive materials for the manufacturing of hazardous gas sensors. The great capabilities of cobalt corroles for the trapping of carbon monoxide (CO) were exploited to produce selective sensors. These corroles were deposited on SAW delay lines surfaces and then exposed to carbon monoxide (CO) in standard conditions. Concentrations of a few hundreds of ppb were measured emphasizing the interest of such sensors for the detection of CO. Another type of sensitive layers exhibiting specific porosity adapted to the trapping of formaldehyde (CH2O) were deposited on similar delay lines. A detection threshold of 140 ppb was shown. These encouraging results pave the way for the development of a functionalized SAW sensors network for multi-gas detection in indoor air. Full article
Open AccessProceedings Low Temperature CVD Grown Graphene for Highly Selective Gas Sensors Working under Ambient Conditions
Proceedings 2017, 1(4), 445; doi:10.3390/proceedings1040445
Published: 16 August 2017
PDF Full-text (456 KB)
Abstract
In this paper we report on gas sensors based on graphene grown by Chemical Vapor Deposition at 850 °C. Mo was used as catalyst for graphene nucleation. Resistors were directly designed on pre-patterned Mo using the transfer-free process we recently developed, thus avoiding
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In this paper we report on gas sensors based on graphene grown by Chemical Vapor Deposition at 850 °C. Mo was used as catalyst for graphene nucleation. Resistors were directly designed on pre-patterned Mo using the transfer-free process we recently developed, thus avoiding films damage during the transfer to the target substrate. Devices operating at room temperature and relative humidity set at 50% were tested towards NO2. The sensors resulted to be highly specific towards NO2 and showed current variation up to 6%. The performances were compared with those of gas sensors based on graphene grown at 980 °C, which represents the usual growth temperature for such material. The findings show that by lowering the graphene growth temperature and consequently the energy consumptions the sensing benefits of these devices are still preserved. Full article
Open AccessProceedings Influence of Electrical Modes on Radiation Sensitivity of Hydrogen Sensors Based on Pd-Ta2O5-SiO2-Si Structures
Proceedings 2017, 1(4), 446; doi:10.3390/proceedings1040446
Published: 25 August 2017
PDF Full-text (628 KB)
Abstract
The influence of the circuit’s electric modes on the radiation sensitivity of hydrogen sensors based on the metal-insulator-semiconductor field-effect transistor with structure Pd-Ta2O5-SiO2-Si (MISFET) was investigated. There were measured the hydrogen responses of output voltages V of
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The influence of the circuit’s electric modes on the radiation sensitivity of hydrogen sensors based on the metal-insulator-semiconductor field-effect transistor with structure Pd-Ta2O5-SiO2-Si (MISFET) was investigated. There were measured the hydrogen responses of output voltages V of the MISFET-based circuits at different gate voltages before and after the electron irradiations. The voltages V as functions of hydrogen concentration C were determined for different ionizing doses D. Models of influence of the electric modes on the radiation sensitivity of sensors were based on experimental dependencies of V(C, D). The recommendations for the optimal choice of MISFET-based circuit’s electric modes were formulated. Full article
Open AccessProceedings A Gas Sensor Device for Oxygen and Carbon Dioxide Detection
Proceedings 2017, 1(4), 447; doi:10.3390/proceedings1040447
Published: 11 August 2017
PDF Full-text (427 KB)
Abstract
Sensors for monitoring oxygen and carbon dioxide are crucial as investigational devices in many different research fields, including environmental, biomedical and industrial. They must be easily configurable, fast responding, and with good reproducibility and sensitivity. The state of art reports different sensing and
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Sensors for monitoring oxygen and carbon dioxide are crucial as investigational devices in many different research fields, including environmental, biomedical and industrial. They must be easily configurable, fast responding, and with good reproducibility and sensitivity. The state of art reports different sensing and transducing strategies: electrochemical, optical, conductometric etc., based on specific chemically interactive materials. In this work, a multisensor system based on electrochemical sensors acting via a liquid medium and controlled by a dedicated low-noise electronic interface is equipped with an elaboration unit able in extracting/storing a committed model for oxygen and carbon dioxide detection. Full article
Open AccessProceedings Study of Poly(3-hexyltiophene) Polymer Sensing Properties in Nerve Agent Simulant (DMMP) Detection
Proceedings 2017, 1(4), 448; doi:10.3390/proceedings1040448
Published: 11 August 2017
PDF Full-text (833 KB)
Abstract
In the present work we report the use of regioregular poly(3-hexyltiophene) polymer (RR-P3HT) as a resistive sensor for the detection of chemical nerve agent simulant, dimethyl methylphosphonate (DMMP). The electrical response to DMMP vapour of RR-P3HT film deposited on ceramic (Al2O
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In the present work we report the use of regioregular poly(3-hexyltiophene) polymer (RR-P3HT) as a resistive sensor for the detection of chemical nerve agent simulant, dimethyl methylphosphonate (DMMP). The electrical response to DMMP vapour of RR-P3HT film deposited on ceramic (Al2O3) substrate in the room temperature was investigated. Results show that studied material is sensitive to DMMP trace amounts and selective against acetone and methanol. It also exhibits fast response and recovery times, repeatability and short-term stability. Full article
Open AccessProceedings Gas Sensing Properties of MoO3
Proceedings 2017, 1(4), 449; doi:10.3390/proceedings1040449
Published: 16 August 2017
PDF Full-text (2220 KB)
Abstract
In the present work, we studied the controlled growth of MoO3 nanostructures and their gas sensing performance. MoO3 NS were synthesized using thermal evaporation method. FE-SEM (LEO 1525) and XRD were used to characterize the morphology and crystallinity of MoO3
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In the present work, we studied the controlled growth of MoO3 nanostructures and their gas sensing performance. MoO3 NS were synthesized using thermal evaporation method. FE-SEM (LEO 1525) and XRD were used to characterize the morphology and crystallinity of MoO3 NS. Sensing devices were mounted on TO packages using electro-soldered gold wires, and they were tested toward some chemical compounds. These NS give reversible response to Acetone, Ethanol and H2 in a temperature range of 300–550 °C. MoO3 sensors exhibit a high response ∆G/G = 45 towards 50 ppm of Ethanol at 450 °C. Full article
Open AccessProceedings Quantitative Analysis of Wine Mixtures Using an Electronic Olfactory System
Proceedings 2017, 1(4), 450; doi:10.3390/proceedings1040450
Published: 8 August 2017
PDF Full-text (797 KB)
Abstract
An electronic nose has been used for the quantification of wines formed by binary mixtures of two white wine varieties and of two red wine varieties. The wines were elaborated at the Instituto Madrileño de Investigación y Desarrollo Rural (IMIDRA) by the traditional
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An electronic nose has been used for the quantification of wines formed by binary mixtures of two white wine varieties and of two red wine varieties. The wines were elaborated at the Instituto Madrileño de Investigación y Desarrollo Rural (IMIDRA) by the traditional method using commercial and autochthonous Saccharomyces cerevisiae yeasts. It is important to note that this technology is faster, simpler and objective than the sensing analysis (human panel). In addition the measurements can be realized in situ and on line. The measurements of the wine mixtures have been analyzed by Partial Least Squares and Artificial Neuronal Networks. Full article
Open AccessProceedings Title Enhancement of the Sensitivity of a Volatile Organic Compounds MOF-Sensor by Means of Its Structure
Proceedings 2017, 1(4), 451; doi:10.3390/proceedings1040451
Published: 16 August 2017
PDF Full-text (976 KB)
Abstract
In this paper, we experimentally compare several core structures of Microstructured Optical Fibers (MOFs) for low-finesse Fabry-Pérot (FP) sensors. These sensors are designed for Volatile Organic Compounds (VOCs) measurements. We deposit Indium Tin Oxide (ITO) thin films by sputtering on the MOFs and
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In this paper, we experimentally compare several core structures of Microstructured Optical Fibers (MOFs) for low-finesse Fabry-Pérot (FP) sensors. These sensors are designed for Volatile Organic Compounds (VOCs) measurements. We deposit Indium Tin Oxide (ITO) thin films by sputtering on the MOFs and different optical phase responses of the FP were measured for saturated atmospheres of ethanol. The sensitivity of the developed sensors is demonstrated to depend on the geometry and the dimensions of the MOF-cores. The sensors show recovery times under 100 s and the baselines are fully recovered after exposure to VOC. Full article
Open AccessProceedings Detection of Nitrate/Nitrite Using BDD Electrodes Coated with Metal Nano-Catalysts
Proceedings 2017, 1(4), 452; doi:10.3390/proceedings1040452
Published: 11 August 2017
PDF Full-text (587 KB)
Abstract
The aim of this work is to investigate the mechanisms of nitrate and nitrite ions electro-reduction in neutral solution at boron doped diamond (BDD) electrodes modified with metal catalyst nanoparticles. The electrode preparation consists in sputtering a thin metal layer onto polycrystalline BDD
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The aim of this work is to investigate the mechanisms of nitrate and nitrite ions electro-reduction in neutral solution at boron doped diamond (BDD) electrodes modified with metal catalyst nanoparticles. The electrode preparation consists in sputtering a thin metal layer onto polycrystalline BDD by a physical vapor deposition method, followed by a dewetting heat treatment at 700 °C under oxygen-free atmosphere. Such a process leads to a stable population of nanosized metal particles as characterized by scanning electron microscopy (SEM) and cyclic voltammetry. Electro-reduction of NO2 and NO3 was characterized both on a bare BDD electrode and on BDD electrodes decorated with platinum-gold, ruthenium-gold and ruthenium nanoparticles in the range 4 to 25 mM. The amperometric response was enhanced by the presence of the nanoparticles, the most sensitive electrode being Pt-Au/BDD and Ru-Au/BDD for nitrite and nitrate ions, respectively. Full article
Open AccessProceedings Improving Calibration of Chemical Gas Sensors for Fire Detection Using Small Scale Setups
Proceedings 2017, 1(4), 453; doi:10.3390/proceedings1040453
Published: 9 August 2017
PDF Full-text (487 KB)
Abstract
Chemical sensing may be better suited than conventional smoke-based detectors for the detection of certain type of fires, in particular in fires where smoke appears after gas emissions. However, chemical-based systems also respond to non-fire scenarios that also release volatiles. For this reason,
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Chemical sensing may be better suited than conventional smoke-based detectors for the detection of certain type of fires, in particular in fires where smoke appears after gas emissions. However, chemical-based systems also respond to non-fire scenarios that also release volatiles. For this reason, discrimination models need to be trained under different fire and non-fire scenarios. This is usually performed in standard fire rooms, the access to which is very costly. In this work, we present a calibration model combining experiments from standard fire room and small-scale setup. Results show that the use of small-scale setup experiments improve the performance of the system. Full article
Open AccessProceedings Investigation of Gasochromic Rhodium Complexes Regarding Their Reactivity towards CO
Proceedings 2017, 1(4), 454; doi:10.3390/proceedings1040454
Published: 17 August 2017
PDF Full-text (562 KB)
Abstract
The detection of the toxic gas carbon monoxide (CO) in the low ppm range is required in different applications. We present a study of the reactivity of different gasochromic rhodium complexes towards the toxic gas carbon monoxide (CO). Therefore, the binuclear rhodium complexes
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The detection of the toxic gas carbon monoxide (CO) in the low ppm range is required in different applications. We present a study of the reactivity of different gasochromic rhodium complexes towards the toxic gas carbon monoxide (CO). Therefore, the binuclear rhodium complexes with different ligands were prepared and their influence regarding reaction velocity and sensitivity towards CO was investigated. The most promising rhodium complex was embedded into a polymer with which glass substrates were coated. The reactivity towards CO of these layers was also investigated. Full article
Open AccessProceedings 2D SnS2—A Material for Impedance-Based Low Temperature NOx Sensing?
Proceedings 2017, 1(4), 455; doi:10.3390/proceedings1040455
Published: 9 August 2017
PDF Full-text (438 KB)
Abstract
The sensor signal of tin disulfide (SnS2), a two-dimensional (2D) group-IV dichalcogenide, deposited as a film on a conductometric transducer is investigated at 130 °C. The focus is on the detection of the total NOx concentration. Therefore, the sensor response
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The sensor signal of tin disulfide (SnS2), a two-dimensional (2D) group-IV dichalcogenide, deposited as a film on a conductometric transducer is investigated at 130 °C. The focus is on the detection of the total NOx concentration. Therefore, the sensor response to NO and NO2 at ppm- and sub-ppm level at low operating temperature is determined. The results show that the sensing device provides a high sensor signal to NO and NO2 even at concentrations of only 390 ppb NOx. Both nitrous components, NO and NO2, yield the same signal, which offers the opportunity to sense the total concentration of NOx. Full article
Open AccessProceedings Study of YSZ Electrolyte Inks for Preparation of Screen-Printed Mixed-Potential Sensors for Selective Detection of NOx and NH3
Proceedings 2017, 1(4), 456; doi:10.3390/proceedings1040456
Published: 16 August 2017
PDF Full-text (640 KB)
Abstract
Among all NOx reduction approaches, selective catalyst reduction (SCR) system is one the most reliable ways to control NOx emissions from diesel engine vehicles and trucks. In order to optimize the conversion rates of NOx and to prevent inducing excessive
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Among all NOx reduction approaches, selective catalyst reduction (SCR) system is one the most reliable ways to control NOx emissions from diesel engine vehicles and trucks. In order to optimize the conversion rates of NOx and to prevent inducing excessive NH3 to the air, an NH3 and NOx sensor is required. In this study, three different types of YSZ ink have been examined to identify the most effective electrolyte for NOx and NH3 sensing. The results have shown that a home-made ink with YSZ powder shows the best sensitivity towards ammonia without polarization and the highest NO2/NO signal ratio with polarization current of 25 nA. Full article
Open AccessProceedings Exhaust Gas Analysis of Firewood Combustion Processes: Application of a Robust Thermoelectric Gas Sensor
Proceedings 2017, 1(4), 457; doi:10.3390/proceedings1040457
Published: 8 August 2017
PDF Full-text (572 KB)
Abstract
The quality of firewood combustion processes can be considerably improved by automated control of the combustion air streams. For this purpose, continuous flue gas analysis using in-situ sensors is essential. In order to monitor the unburned exhaust gas components like carbon monoxide (CO)
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The quality of firewood combustion processes can be considerably improved by automated control of the combustion air streams. For this purpose, continuous flue gas analysis using in-situ sensors is essential. In order to monitor the unburned exhaust gas components like carbon monoxide (CO) and hydrocarbons (CxHy), for the first time a novel thermoelectric gas sensor was applied directly in the exhaust gas. The sensor is made of high temperature stable materials and promises the needed robustness. Here, the sensor signal is compared to flue gas analysis data from FTIR measurements during a wood-log batch firing experiment. An impressive correlation between both data was found. Full article
Open AccessProceedings Gas Sensing Characterization of Single-Nanowire Sensor Array Systems Based on Non-Functionalized and Pt-Functionalized Tungsten Oxide
Proceedings 2017, 1(4), 458; doi:10.3390/proceedings1040458
Published: 9 August 2017
PDF Full-text (976 KB)
Abstract
Here we present the gas sensing characterization of single-nanowire sensor array systems based on either non-functionalized or Pt-functionalized single tungsten oxide nanowires towards various concentrations of nitrogen dioxide and ethanol. The sensor systems demonstrate stable and reproducible responses to the tested analytes, showing
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Here we present the gas sensing characterization of single-nanowire sensor array systems based on either non-functionalized or Pt-functionalized single tungsten oxide nanowires towards various concentrations of nitrogen dioxide and ethanol. The sensor systems demonstrate stable and reproducible responses to the tested analytes, showing consistency with previous systems based on multiple-nanowire based films and validating the fabrication process of these devices. Full article
Open AccessProceedings Evaluation of MOX Sensor Characteristics in Ultra-Low Power Operation Modes: Application to a Semi-Passive RFID Tag for Food Logistics
Proceedings 2017, 1(4), 459; doi:10.3390/proceedings1040459
Published: 8 August 2017
PDF Full-text (383 KB)
Abstract
Most of the battery powered systems with integrated sensors need low power consumption modes to enlarge the operation time. In the case of the fruit logistic chain, the fruit quality may be controlled by the detection of some gases as ethylene, acetaldehyde and
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Most of the battery powered systems with integrated sensors need low power consumption modes to enlarge the operation time. In the case of the fruit logistic chain, the fruit quality may be controlled by the detection of some gases as ethylene, acetaldehyde and ammonia, that are related to maturation, oxygen stress and refrigeration leakage. We report the integration of an ultra-low power (ULP) metal oxide (MOX) sensor array inside a Radio Frequency IDentification (RFID) 13.56 MHz ISO/IEC 15693 compliant tag with temperature, humidity and light sensors and data logging capabilities. Pulsed Temperature Operation (PTO), which consists in switching on and off the sensor heater, was used to reduce power consumption more than three orders of magnitude, from 14 mW down to 7 μW. The sensor behavior was characterized in terms sensitivity for ammonia. Full article
Open AccessProceedings Influence of Metal Catalyst on SnO2 Nanowires Growth and Gas Sensing Performance
Proceedings 2017, 1(4), 460; doi:10.3390/proceedings1040460
Published: 11 August 2017
PDF Full-text (1058 KB)
Abstract
In the present work SnO2 nanowires were synthetized by using vapour-liquid-solid technique (VLS) on alumina substrates, using different metal nanoparticles as catalyst for the growth. In particular, the effect of Au, Sn and Pd nanoparticles was exploited. The growth was performed simultaneously
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In the present work SnO2 nanowires were synthetized by using vapour-liquid-solid technique (VLS) on alumina substrates, using different metal nanoparticles as catalyst for the growth. In particular, the effect of Au, Sn and Pd nanoparticles was exploited. The growth was performed simultaneously on all substrates, keeping the same conditions for the three different catalysts used. Nanowires were investigated by FE-SEM, HR-TEM, and XRD measurements, confirming the morphology and the crystalline structure of the material. Moreover, conductometric sensing devices were fabricated depositing electrodes on top of these materials, and chemical sensing performances were evaluated toward some typical air pollutants. Full article
Open AccessProceedings The Effect of Monolayer Graphene on the UV Assisted NO2 Sensing and Recovery at Room Temperature
Proceedings 2017, 1(4), 461; doi:10.3390/proceedings1040461
Published: 22 August 2017
PDF Full-text (796 KB)
Abstract
In the present study, UV light induced desorption of nitrogen dioxide (NO2) on pristine graphene based gas sensor is used to improve the sensing performance. Compared to the sample without UV light exposure, the response is 12%, 18% and 21% for
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In the present study, UV light induced desorption of nitrogen dioxide (NO2) on pristine graphene based gas sensor is used to improve the sensing performance. Compared to the sample without UV light exposure, the response is 12%, 18% and 21% for NO2 concentrations of 1, 3 and 5 ppm. In addition, the recovery could be speeded up by UV irradiation. The sensor shows good behavior of repeatability when tested for 1 ppm of NO2 in 3 cycles. The graphene sensor with UV irradiation has a higher sensitivity to NO2 than to other gases under higher concentrations. Full article
Open AccessProceedings Improving Sensitivity of a Chemoresistive Hydrogen Sensor by Combining ZIF-8 and ZIF-67 Nanocrystals
Proceedings 2017, 1(4), 462; doi:10.3390/proceedings1040462
Published: 28 August 2017
PDF Full-text (2129 KB)
Abstract
In the present work, nanostructures of zeolitic imidazolate frameworks (ZIF-8 and ZIF-67) were combined to obtain a novel chemoresistive sensor, improving the sensitivity of ZIF-67 and facilitating measurement of ZIF-8 by decreasing the resistivity. The sensor detected concentrations as low as 10 ppm
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In the present work, nanostructures of zeolitic imidazolate frameworks (ZIF-8 and ZIF-67) were combined to obtain a novel chemoresistive sensor, improving the sensitivity of ZIF-67 and facilitating measurement of ZIF-8 by decreasing the resistivity. The sensor detected concentrations as low as 10 ppm of hydrogen increasing its resistivity about 4.5 times. The response of the sensor was compared with a similar chemoresistive sensor based exclusively on ZIF-67, and the sensitivity was around three times higher in the case of the sensor with ZIFs combination. Full article
Open AccessProceedings Pt-AlGaN/GaN HEMT-Sensor for Hydrogen Sulfide (H2S) Detection
Proceedings 2017, 1(4), 463; doi:10.3390/proceedings1040463
Published: 8 August 2017
PDF Full-text (544 KB)
Abstract
AlGaN/GaN high electron mobility transistor (HEMT)-sensor with a catalytic Pt-gate is fabricated and tested for toxic H2S gas detection. AlGaN/GaN was chosen to extend the sensor detection range and to be able to operate at temperatures beyond those allowed by state-of-art
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AlGaN/GaN high electron mobility transistor (HEMT)-sensor with a catalytic Pt-gate is fabricated and tested for toxic H2S gas detection. AlGaN/GaN was chosen to extend the sensor detection range and to be able to operate at temperatures beyond those allowed by state-of-art Si-FET sensors. Testing was performed using a gas mixing apparatus in dry synthetic air ambient. High sensitivity, ΔI/I0, 8% for 80 ppm and 0.23% for 0.5 ppm H2S/air, is achieved at a temperature of 250 °C, with a corresponding ΔI of 617 μA and 18 μA, respectively, indicating suitability of the proposed sensor for industrial gas safety detectors. Full article
Open AccessProceedings Solid-Contact Reference Electrode for Ion-Selective Sensors
Proceedings 2017, 1(4), 464; doi:10.3390/proceedings1040464
Published: 25 August 2017
PDF Full-text (300 KB)
Abstract
This work presents a flexible miniaturized ion-selective sensor consisting of a solid-contact reference electrode (RE) and ion-selective electrodes (ISE) fabricated on the same foil. The flexible ion sensor was based on AgCl electrodes screen printed on polyethylene terephthalate foil. The RE was formed
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This work presents a flexible miniaturized ion-selective sensor consisting of a solid-contact reference electrode (RE) and ion-selective electrodes (ISE) fabricated on the same foil. The flexible ion sensor was based on AgCl electrodes screen printed on polyethylene terephthalate foil. The RE was formed by casting a mixture of plasticized polyvinylchloride (PVC) and KCl on the AgCl electrode. The ISE consisted of a stack of AgCl electrode, cellulose gel layer loaded with 0.1 M KCl, and plasticized PVC based ion-selective membrane containing ionophores. The flexible ion sensor showed a sensitivity close to the Nernstian value in a biological relevant range. Full article
Open AccessProceedings Study of a Layered Au, Pt-YSZ Mixed-Potential Sensing Electrode by ESEM, XRD and GD-OES with Relation to Its Electrochemical Behaviour
Proceedings 2017, 1(4), 465; doi:10.3390/proceedings1040465
Published: 22 August 2017
PDF Full-text (818 KB)
Abstract
Morphological and structural properties of layered Au, Pt-YSZ mixed-potential gas sensing electrodes (APE) prepared under different temperature treatments were studied by environmental scanning electron microscope (ESEM) and glow-discharge optical emission spectroscopy (GD-OES), and correlated with open-circuit potential (OCP) and cyclic voltammetry (CV) measurements
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Morphological and structural properties of layered Au, Pt-YSZ mixed-potential gas sensing electrodes (APE) prepared under different temperature treatments were studied by environmental scanning electron microscope (ESEM) and glow-discharge optical emission spectroscopy (GD-OES), and correlated with open-circuit potential (OCP) and cyclic voltammetry (CV) measurements under gas exposures at elevated temperatures. The OCP response of the APE sintered at 1050 °C is clearly higher than that of the APE sintered at 850 °C, and can be well correlated with a smaller oxygen reduction reaction (ORR) observed in the related CV diagrams. Moreover, a transition from the charge transfer reaction kinetics to the diffusional transport controlled mixed-potential formation was found between 550 °C and 650 °C. Full article
Open AccessProceedings H2-Sensing Performance of 2D WO3 Nanostructure—Effect of Anodization Parameter
Proceedings 2017, 1(4), 466; doi:10.3390/proceedings1040466
Published: 17 August 2017
PDF Full-text (1475 KB)
Abstract
In this work, we investigate the effect of HNO3 anodizing solution concentration ranging from 1.5 to 3 M on H2-sensing performance of 2D WO3 nanostructures prepared by anodizing sputtered tungsten films. The thickness of WO3 nanosheets was found
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In this work, we investigate the effect of HNO3 anodizing solution concentration ranging from 1.5 to 3 M on H2-sensing performance of 2D WO3 nanostructures prepared by anodizing sputtered tungsten films. The thickness of WO3 nanosheets was found to reduce while the crystallinity degraded with increasing HNO3 concentration. However, the nanosheets anodized in 2 M HNO3 exhibited the highest response of 43.4 to 1 vol % H2, which was one order of magnitude larger than those fabricated with other concentrations at the optimal operating temperature of 350 °C. In addition, the optimal nanostructures displayed good H2 selectivity against NO2, CH4, C2H2 and C2H5OH. Full article
Open AccessProceedings 3D Graphene-Carbon Nanotubes-Polydimethyl Siloxane Flexible Electrodes for Simultaneous Electrochemical Detections of Hg, Pb and Cd
Proceedings 2017, 1(4), 467; doi:10.3390/proceedings1040467
Published: 18 August 2017
PDF Full-text (1103 KB)
Abstract
In this work, the effect of CNTs content in 3D graphene-PDMS-CNTs electrodes were systematically studied for simultaneous determination of Hg, Pb and Cd by differential pulse anodic stripping voltammetry. The composites were formed by dip coating CVD graphene on Ni foam in CNTs-dispersed
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In this work, the effect of CNTs content in 3D graphene-PDMS-CNTs electrodes were systematically studied for simultaneous determination of Hg, Pb and Cd by differential pulse anodic stripping voltammetry. The composites were formed by dip coating CVD graphene on Ni foam in CNTs-dispersed PDMS solution with varying CNTs concentrations. The optimal CNTs content was found to be ~0.5 mg/mL for all analytes. The optimal graphene-PDMS-CNTs electrode showed good analytical performances with sharp well-separated peaks of Pb, Hg and Cd in the concentration range of 100–500 μg/L. Therefore, the graphene-PDMS-CNTs electrode is highly promising for multiple detections of heavy metal pollutants. Full article
Open AccessProceedings Individual Gallium Oxide Nanowires for Humidity Sensing at Low Temperature
Proceedings 2017, 1(4), 468; doi:10.3390/proceedings1040468
Published: 8 August 2017
PDF Full-text (578 KB)
Abstract
Gallium oxide nanowires (NWs) were synthetized using a vapor-liquid-solid route via carbothermal reduction. These NWs were characterized using XRD, SEM and TEM as well as photoluminescence spectroscopy, confirming their crystalline nature. Gas sensors, based on individual NWs, deposited on suspended microhotplates, were tested
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Gallium oxide nanowires (NWs) were synthetized using a vapor-liquid-solid route via carbothermal reduction. These NWs were characterized using XRD, SEM and TEM as well as photoluminescence spectroscopy, confirming their crystalline nature. Gas sensors, based on individual NWs, deposited on suspended microhotplates, were tested towards several gases of interest at different temperatures. The sensing towards relative humidity provided the best results, with responses up to 20% at room temperature (~25 °C). Full article
Open AccessProceedings GO/2D WS2 Based Humidity Sensor
Proceedings 2017, 1(4), 469; doi:10.3390/proceedings1040469
Published: 11 October 2017
PDF Full-text (268 KB)
Abstract
In this work, 2D WS2 nanosheets prepared by the exfoliation of WS2 with Li-intercalation was combined with GO produced by the Hummer method for humidity sensing applications. The GO and WS2 solutions were mixed with an equal concentration and coated
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In this work, 2D WS2 nanosheets prepared by the exfoliation of WS2 with Li-intercalation was combined with GO produced by the Hummer method for humidity sensing applications. The GO and WS2 solutions were mixed with an equal concentration and coated on conductometric transducers. Sensing measurements towards humidity (0–80% RH) at room temperature revealed that the humidity response of hybrid was substantially higher by a factor of 3–9 depending on the RH value compared with those of GO and WS2. Moreover, no cross sensitivity to common gaseous compounds was observed. Therefore, the GO/2D WS2 composite is a highly promising humidity sensor. Full article
Open AccessProceedings Design, Fabrication and Optimization of a Silicon MEMS Natural Gas Sensor
Proceedings 2017, 1(4), 470; doi:10.3390/proceedings1040470
Published: 17 August 2017
PDF Full-text (661 KB)
Abstract
This study reports on the integration of a Silicon MEMS hotplate into a natural gas quality analyzer, i.e., a miniaturized gas viscometer used to measure the Wobbe Index (WI). COMSOL Multiphysics simulation was used for selection of the optimum geometry of the hotplate
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This study reports on the integration of a Silicon MEMS hotplate into a natural gas quality analyzer, i.e., a miniaturized gas viscometer used to measure the Wobbe Index (WI). COMSOL Multiphysics simulation was used for selection of the optimum geometry of the hotplate and gas sensing cell. Experimental characterization of the hotplate confirmed its stability under working condition of the sensor. The sensor has been tested by running various gases such as Nitrogen and Methane. The thermal analysis of the sensor and experimental results show a reduced response time of the sensor at lower power consumption and lower thermal time constant. Full article
Open AccessProceedings NO2 Measurements with RGB Sensors for Easy In-Field Test
Proceedings 2017, 1(4), 471; doi:10.3390/proceedings1040471
Published: 25 August 2017
PDF Full-text (323 KB)
Abstract
We present a simple an inexpensive method to implement a Griess-Saltzman-type reaction that combines the advantages of the liquid phase method (high specificity, fast response time) with the benefits of a solid implementation (easy to handle). We demonstrate that the measurements can be
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We present a simple an inexpensive method to implement a Griess-Saltzman-type reaction that combines the advantages of the liquid phase method (high specificity, fast response time) with the benefits of a solid implementation (easy to handle). We demonstrate that the measurements can be carried out using conventional RGB sensors; circumventing all the limitations around the measurement of the samples with spectrometers. We also present a method to optimize the measurement protocol and target a specific range of NO2 concentrations. We demonstrate that it is possible to measure the concentration of NO2 from 50 ppb to 300 ppm with high specificity and without modifying the sensing elements. Full article
Open AccessProceedings Capacitive CO2 Sensor
Proceedings 2017, 1(4), 472; doi:10.3390/proceedings1040472
Published: 11 August 2017
PDF Full-text (610 KB)
Abstract
The objective of the present paper is to provide a concept for a chemical sensor having a small size, a low power consumption and a high reliability for sensing CO2 under different humidity levels at atmospheric pressure, while maintaining a long term
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The objective of the present paper is to provide a concept for a chemical sensor having a small size, a low power consumption and a high reliability for sensing CO2 under different humidity levels at atmospheric pressure, while maintaining a long term stability under working conditions. A high temperature regeneration process of the sensing layer is unneeded to ensure a long term stability of the sensing material. This objective is achieved by using a hybrid organic-inorganic nanomaterial, consisting of inorganic nanoparticles functionalized with an amine-based polymer. Full article
Open AccessProceedings Cairsens NO2: A Miniature Device Dedicated to the Indicative Measurement of Nitrogen Dioxide in Ambient Air
Proceedings 2017, 1(4), 473; doi:10.3390/proceedings1040473
Published: 28 August 2017
PDF Full-text (452 KB)
Abstract
This paper reports the study of data quality of Cairsens NO2 environmental sensors. In order to evaluate sensors performances, the investigation was performed through: a prospective follow-up of short-term and long terms drifts, the evaluation of the effects of environmental conditions upon
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This paper reports the study of data quality of Cairsens NO2 environmental sensors. In order to evaluate sensors performances, the investigation was performed through: a prospective follow-up of short-term and long terms drifts, the evaluation of the effects of environmental conditions upon sensors measurements as well as the evaluation of the ozone-filter lifetime. In this purpose, a dedicated test bench has been developed to expose sensors to a fixed concentration of ozone while recording sensors response. Full article
Open AccessProceedings Detection of Ethanol in Human Breath Using Optical Fiber Long Period Grating Coated with Metal-Organic Frameworks
Proceedings 2017, 1(4), 474; doi:10.3390/proceedings1040474
Published: 21 August 2017
PDF Full-text (510 KB)
Abstract
An optical fiber sensor for ethanol detection in exhaled breath has been developed. It has been fabricated by functionalizing a Long Period Grating with a metal-organic framework, ZIF-8. The sensor’s response was tested by exposure to exhaled breath of a person before and
[...] Read more.
An optical fiber sensor for ethanol detection in exhaled breath has been developed. It has been fabricated by functionalizing a Long Period Grating with a metal-organic framework, ZIF-8. The sensor’s response was tested by exposure to exhaled breath of a person before and after the ingestion of alcoholic drinks, showing a higher wavelength difference between the resonance bands in the second case. Further work will analyze cross-sensitivity towards temperature, relative humidity and carbon dioxide. Full article
Open AccessProceedings Sensitivity to Heavy-Metal Ions of Cage-Opening Fullerene Quantum Dots
Proceedings 2017, 1(4), 475; doi:10.3390/proceedings1040475
Published: 19 August 2017
Cited by 1 | PDF Full-text (374 KB)
Abstract
In this study, we have carried out a characterization of the quenching effect produced by some commonly encountered metal ions (Co2+, Cu2+, Ni2+, Pb2+, Cd2+, As5+) on the photoluminescence of water
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In this study, we have carried out a characterization of the quenching effect produced by some commonly encountered metal ions (Co2+, Cu2+, Ni2+, Pb2+, Cd2+, As5+) on the photoluminescence of water suspensions of open-cage fullerene quantum dots prepared with a modified Hummers method. The response to heavy-metal ions occurs through a selective quenching of the PL emission and modifications of the absorption spectrum. Full article
Open AccessProceedings Separation of Sensitivity Contributions in Tin Oxide Thick Film Sensors by Transmission Line Model Measurements at Isothermal and Thermally Modulated Operation
Proceedings 2017, 1(4), 476; doi:10.3390/proceedings1040476
Published: 9 August 2017
PDF Full-text (894 KB)
Abstract
Transmission line modelling (TLM) techniques were used to study the sensitivity behaviour to CO and propene in distinct regions of tin oxide thick film gas sensors operated in isothermal and thermo-cyclic mode. The sensitive layer showed an increased sensitivity to propene in the
[...] Read more.
Transmission line modelling (TLM) techniques were used to study the sensitivity behaviour to CO and propene in distinct regions of tin oxide thick film gas sensors operated in isothermal and thermo-cyclic mode. The sensitive layer showed an increased sensitivity to propene in the vicinity of the Pt electrodes at isothermal operation and pronounced specific features at thermo-cyclic operation. Simulation by Finite Element Analysis (FAE) gives insight into the electrical behaviour of the contact area and enables a detailed analysis of the thickness dependence of sensitivity effects. Full article
Open AccessProceedings Restraining the Diffusion of Photocarriers to Improve the Spatial Resolution of the Chemical Imaging Sensor
Proceedings 2017, 1(4), 477; doi:10.3390/proceedings1040477
Published: 3 August 2017
PDF Full-text (1026 KB)
Abstract
The chemical imaging sensor is capable of visualizing the ion distribution. The spatial resolution of the chemical image depends on the horizontal diffusion of photocarriers generated by illumination. In this study; a novel optics is designed to realize a hybrid illumination of a
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The chemical imaging sensor is capable of visualizing the ion distribution. The spatial resolution of the chemical image depends on the horizontal diffusion of photocarriers generated by illumination. In this study; a novel optics is designed to realize a hybrid illumination of a ring of constant light and a spot of modulated light. Improved spatial resolution of the order of few tens of microns was successfully demonstrated. Full article
Open AccessProceedings Dual Gate Microsensors and Nanomaterials for Chemical Detection
Proceedings 2017, 1(4), 478; doi:10.3390/proceedings1040478
Published: 11 August 2017
PDF Full-text (745 KB)
Abstract
New chemical sensors are developed for suitable applications in biochemistry and biology, especially for the easy measurement of low concentrations of chemical and biological elements in liquid media. Robust devices, able to detect a small charge variation, can be associated with nanomaterials on
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New chemical sensors are developed for suitable applications in biochemistry and biology, especially for the easy measurement of low concentrations of chemical and biological elements in liquid media. Robust devices, able to detect a small charge variation, can be associated with nanomaterials on the active surface of the sensor. Sensors based on microelectronic technologies and having high sensitivities due to their specific Dual Gate structure are shown. We demonstrate that, under optimum polarization conditions, the sensor exhibits a high sensitivity for pH variations. The integration of several types of nanomaterials on the active surface of the microsensors is also demonstrated and validated for further biological detections Full article
Open AccessProceedings Aryl-Diazonium Functionalized Polycrystalline Silicon Nanoribbons Based Device for Lead Detection
Proceedings 2017, 1(4), 479; doi:10.3390/proceedings1040479
Published: 28 August 2017
PDF Full-text (1473 KB)
Abstract
Development of sensors enabling lead traces detection is a burning issue as heavy metals ions are responsible of brain diseases. In this paper, we present a simple electronic resistor based on polycrystalline silicon nanoribbons and functionalized with aryl-diazonium salts in view of using
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Development of sensors enabling lead traces detection is a burning issue as heavy metals ions are responsible of brain diseases. In this paper, we present a simple electronic resistor based on polycrystalline silicon nanoribbons and functionalized with aryl-diazonium salts in view of using this type of structures for heavy metal detection. The preconcentration of lead at the surface of the functionalized nanostructures has been checked. Finally, electrical characterization of the resistors showed that the sensor sensitivity to these species is improved thanks to functionalization in the range 10−7 to 10−5 mol·L−1. Full article
Open AccessProceedings Conducting Polymers for Ammonia Sensing: Electrodeposition, Hybrid Materials and Heterojunctions
Proceedings 2017, 1(4), 480; doi:10.3390/proceedings1040480
Published: 7 August 2017
PDF Full-text (3049 KB)
Abstract
Polyaniline (PANI) with electrodonating and electrowithdrawing substituents were electrodeposited and studied as sensing materials in resistors and heterojunctions. Whereas the dimethoxyaniline leads to a highly conductive material, the tetrafluoroaniline leads to a poor conducting polymer. However, this latter was used in heterojunctions, associated
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Polyaniline (PANI) with electrodonating and electrowithdrawing substituents were electrodeposited and studied as sensing materials in resistors and heterojunctions. Whereas the dimethoxyaniline leads to a highly conductive material, the tetrafluoroaniline leads to a poor conducting polymer. However, this latter was used in heterojunctions, associated with a highly conductive material, the lutetium bisphthalocyanine LuPc2. Elsewhere, hybrid materials combining polypyrrole (PPy) with ionic macrocycles as counterions were also electrosynthesized and used as sensing material in resistors, for the detection of ammonia. They exhibit a higher sensitivity compared to PPy prepared with small counterions, with a stable response in a broad range of relative humidity. Full article
Open AccessProceedings A Highly Sensitive Potentiometric Amphetamine Microsensor Based on All-Solid-State Membrane Using a New Ion-Par Complex, [3,3′-Co(1,2-closo-C2B9H11)2] C9H13NH+
Proceedings 2017, 1(4), 481; doi:10.3390/proceedings1040481
Published: 7 August 2017
PDF Full-text (351 KB)
Abstract
In the present work a highly sensitive ion-selective microelectrode for the detection of amphetamine is presented. For this purpose, a novel ion-par complex based on the metallocarborane, cobalt bis(dicarbollide) anion ([3,3′-Co(1,2-C2B9H11)2]) coupled to
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In the present work a highly sensitive ion-selective microelectrode for the detection of amphetamine is presented. For this purpose, a novel ion-par complex based on the metallocarborane, cobalt bis(dicarbollide) anion ([3,3′-Co(1,2-C2B9H11)2]) coupled to amphetamonium cation has been prepared as the active site for amphetamine recognition. The prepared ion-par complex was incorporated to a PVC-type sensitive membrane. It was then drop-casted on the top of a gold microelectrode previously modified with a solid contact layer of polypyrrole. This novel amphetamine microsensor has provided excellent and quick response within the range 10−5 M to 10−3 M of amphetamine concentration, a limit of detection of 12 µM and a slope of 60.1 mV/decade. It was also found to be highly selective toward some potential interference compounds when compared to amphetamine. Full article
Open AccessProceedings A Novel, Low-Cost, Portable PID Sensor for Detection of VOC
Proceedings 2017, 1(4), 482; doi:10.3390/proceedings1040482
Published: 7 August 2017
PDF Full-text (536 KB)
Abstract
A low cost portable photoionization (PID) sensor was successfully designed and manufactured. Unlike existing commercial PID sensors, our device provides two outputs, one associated with the total chemical components and a second that provides some level of compositional information. We believe that this
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A low cost portable photoionization (PID) sensor was successfully designed and manufactured. Unlike existing commercial PID sensors, our device provides two outputs, one associated with the total chemical components and a second that provides some level of compositional information. We believe that this makes this sensor system more useful than a standard PID, with a similar, if not lower, cost point. Our PID sensor was tested with gas concentrations down to 2 ppm isobutylene. These results indicate that the limit of detection will be well below 1 ppm. Further detection tests were carried out with ethanol, acetone and isobutylene, which showed similar sensitivities. Compositional measurements were also undertaken and the results presented shows our sensor can discriminate successfully between low concentration isobutylene and 2-pentanone. Full article
Open AccessProceedings Design of Novel Electrochemical Sensors for the Selective Detection of Glyphosate
Proceedings 2017, 1(4), 483; doi:10.3390/proceedings1040483
Published: 8 August 2017
PDF Full-text (748 KB)
Abstract
This study concerns the development of two molecularly imprinted polymers (MIP) based electrochemical sensors for glyphosate detection. In both cases polypyrrole (PPy) was chosen as matrix and glyphosate molecules were the templates. The main difference between the two strategies is related to the
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This study concerns the development of two molecularly imprinted polymers (MIP) based electrochemical sensors for glyphosate detection. In both cases polypyrrole (PPy) was chosen as matrix and glyphosate molecules were the templates. The main difference between the two strategies is related to the investigated electrode: gold surface in the first case, and ZnO nanorods vertically grown on ITO diazonium modified substrates in the second case. The limits of detection (LOD) of these sensors were about 10−13 M and 10−10 M respectively. Full article
Open AccessProceedings High-Performance Ammonia Sensor at Room Temperature Based on a Love-Wave Device with Fe2O3@WO3−x Nanoneedles
Proceedings 2017, 1(4), 484; doi:10.3390/proceedings1040484
Published: 25 August 2017
PDF Full-text (1000 KB)
Abstract
An innovative, simple and inexpensive Love-wave gas sensor based on Fe2O3@WO3−x nanoneedles to detect the variation of ammonia at room temperature was developed. The nanoneedles were successfully formed on Love-wave device via aerosol-assisted chemical vapor deposition (AACVD).
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An innovative, simple and inexpensive Love-wave gas sensor based on Fe2O3@WO3−x nanoneedles to detect the variation of ammonia at room temperature was developed. The nanoneedles were successfully formed on Love-wave device via aerosol-assisted chemical vapor deposition (AACVD). The nanoneedles worked as guiding and sensitive layers detecting the changes of the elastic properties presented by ammonia interaction. The sensor was tested to ammonia concentrations between 25 to 90 ppm and showed large frequency shifts, high sensibility, short response time and good reproducibility. Full article
Open AccessProceedings Ultrasensitive Gas Sensors Based on Electrospun TiO2 and ZnO
Proceedings 2017, 1(4), 485; doi:10.3390/proceedings1040485
Published: 5 September 2017
PDF Full-text (680 KB)
Abstract
New sensors for detecting gases at low concentration were successfully developed. Two metal oxide materials, zinc oxide and titanium dioxide, usually employed both in gas sensing as well as in photocatalytic application, were synthesized both through a traditional sol-gel method and an electrospinning
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New sensors for detecting gases at low concentration were successfully developed. Two metal oxide materials, zinc oxide and titanium dioxide, usually employed both in gas sensing as well as in photocatalytic application, were synthesized both through a traditional sol-gel method and an electrospinning technique. The corresponding thick films were considered with respect to the target gases (acetone for ZnO and carbon monoxide for TiO2) for comparing their functional properties. Full article
Open AccessProceedings Investigation of the Salt Concentration Dependence of Water-Gated Field Effect Transistors (WG-FET) Using 16-nm-Thick Single Crystalline Si Film
Proceedings 2017, 1(4), 486; doi:10.3390/proceedings1040486
Published: 9 August 2017
PDF Full-text (770 KB)
Abstract
This paper presents the effect of NaCl concentration on the operation of a water-gated field effect transistor (WG-FET) that uses 16-nm-thick single crystalline silicon (Si) film. In WG-FET, electrical double layer (EDL) formed at the water/silicon interface behaves as gate dielectric and this
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This paper presents the effect of NaCl concentration on the operation of a water-gated field effect transistor (WG-FET) that uses 16-nm-thick single crystalline silicon (Si) film. In WG-FET, electrical double layer (EDL) formed at the water/silicon interface behaves as gate dielectric and this fluidic interface makes WG-FET a suitable device for sensing applications. Characteristics of EDL and the threshold voltage of WG-FET depend on the molarity of solution. Increasing the molarity of NaCl solution from 0.5 to 65 mM changes the threshold voltage from 360 to 465 mV. Accordingly, drain current of the WG-FET device changes with NaCl concentration. Full article
Open AccessProceedings Oxyhydrogen and Hydrogen Detection by Gasochromic Coloration of Highly Porous Tungsten Oxide with Fractal-Like Pd Nanoparticles
Proceedings 2017, 1(4), 487; doi:10.3390/proceedings1040487
Published: 28 August 2017
PDF Full-text (1370 KB)
Abstract
WO3 thin films were deposited by pulsed laser deposition (PLD) on glass substrates at 100 mTorr oxygen pressure. Monodispersed palladium nanoparticles (50 nm) were synthesized by hydrogen reduction of PdCl2 drop-casted on the surface of the films. For oxyhydrogen detection, first
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WO3 thin films were deposited by pulsed laser deposition (PLD) on glass substrates at 100 mTorr oxygen pressure. Monodispersed palladium nanoparticles (50 nm) were synthesized by hydrogen reduction of PdCl2 drop-casted on the surface of the films. For oxyhydrogen detection, first a saturated coloration by 10%H2/Ar was prepared. Then different oxygen flow with certain O2:H2 ratios were exposed to the colored samples. Depending on this ratio, the optical density of samples was observed to drop into certain new values until vanishes for a ratio about 20. A desirable fast coloration with linear dependency on hydrogen concentration was also observed. Full article
Open AccessProceedings Carbon Dots and Fluorescein: The Ideal FRET Pair for the Fabrication of a Precise and Fully Reversible Ammonia Sensor
Proceedings 2017, 1(4), 488; doi:10.3390/proceedings1040488
Published: 7 August 2017
PDF Full-text (334 KB)
Abstract
Monitoring of ammonia in the human breath is of paramount importance to monitor diseases link to liver and kidney mulfunctioning. The present paper describes a solid-state optical ammonia sensor based on Förster resonance energy transfer (FRET) between narrowly dispersed blue-emitting carbon nanodots (CNDs)
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Monitoring of ammonia in the human breath is of paramount importance to monitor diseases link to liver and kidney mulfunctioning. The present paper describes a solid-state optical ammonia sensor based on Förster resonance energy transfer (FRET) between narrowly dispersed blue-emitting carbon nanodots (CNDs) as FRET donor and fluorescein as FRET acceptor. The fluorophores were physically entrapped in a close to superhydrophobic sol-gel matrix, in turn deposited on a PVDF-HFP electrospun fiber membrane. The sensor shows a linear calibration with a remarkably low limit of detection, i.e., 110 ppb, and adequate reproducibility up to six N2/NH3 cycles. Full article
Open AccessProceedings E-tongue based on Porphyrin Electropolymers for Apulian Red Wines Defects Detection
Proceedings 2017, 1(4), 489; doi:10.3390/proceedings1040489
Published: 8 August 2017
PDF Full-text (254 KB)
Abstract
An application of e-tongue based on porphyrin electropolymers for the detection of Primitivo and Negroamaro wines defects related to the presence of “off-odor” methiol (3-(methylthio)-propanol), isoamyl alcohol fusel oil, the marker of the yeast activity benzaldehyde and vinegar formation marker acetic acid was
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An application of e-tongue based on porphyrin electropolymers for the detection of Primitivo and Negroamaro wines defects related to the presence of “off-odor” methiol (3-(methylthio)-propanol), isoamyl alcohol fusel oil, the marker of the yeast activity benzaldehyde and vinegar formation marker acetic acid was investigated. The best results were obtained for acetic acid and isoamyl alcohol. Further the Soft Independent Modelling by Class Analogy, SIMCA, classification models and Partial Least Squares-Discriminant Analysis, PLS-DA, were employed to distinguish real wine samples with different (permitted and alarm levels) fault compounds content as far as two types of wines among them. Full article
Open AccessProceedings Detection of NOx in Combustion Engine Exhaust Gas by Applying the Pulsed Polarization Technique on YSZ Based Sensors
Proceedings 2017, 1(4), 490; doi:10.3390/proceedings1040490
Published: 9 August 2017
PDF Full-text (600 KB)
Abstract
The pulsed polarization measurement technique applied on sensor devices based on yttria stabilized zirconia (YSZ) with porous platinum electrodes enables the detection of low ppm concentrations of NOx in exhaust gas applications with a simple device. Pulsed polarization is based on alternating voltage
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The pulsed polarization measurement technique applied on sensor devices based on yttria stabilized zirconia (YSZ) with porous platinum electrodes enables the detection of low ppm concentrations of NOx in exhaust gas applications with a simple device. Pulsed polarization is based on alternating voltage pulses with intermediate pauses for self discharging. The discharge characteristics after polarization depends strongly on NOx content in the low ppm range. Due to faster discharging in NOx containing atmospheres compared to base gas, the voltage difference between the discharge curves can act as a concentration dependent parameter. Sensor probes for usage in exhaust gas conditions have been built. The feasibility of NOx sensing in diesel exhaust gas by use of a planar cost-effective YSZ sensor element is evaluated in detail in comparison to commercial NOx exhaust sensors and referenced with gas analysis equipment. Full article
Open AccessProceedings Label-Free Immunodetection in High Ionic Strength Solutions Using Carbon Nanotube Transistors with Nanobody Receptors
Proceedings 2017, 1(4), 491; doi:10.3390/proceedings1040491
Published: 25 August 2017
PDF Full-text (346 KB)
Abstract
Nanomaterial-based field-effect transistors (FETs) have been proposed for real-time, label-free detection of various biological species. However, screening of the analyte charge by electrolyte ions (Debye screening) has so far limited their use in physiological samples. Here, this challenge is overcome by combining FETs
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Nanomaterial-based field-effect transistors (FETs) have been proposed for real-time, label-free detection of various biological species. However, screening of the analyte charge by electrolyte ions (Debye screening) has so far limited their use in physiological samples. Here, this challenge is overcome by combining FETs based on single-walled semiconducting carbon nanotube networks (SWCNTs) with a novel surface functionalization comprising: (1) short nanobody receptors, and (2) a polyethylene glycol layer (PEG). Nanobodies are stable, easy-to-produce, short biological receptors (~2–4 nm) that enable analyte binding closer to the sensor surface. The addition of PEG enhances the signal in high ionic strength environment. Using green fluorescent protein (GFP) as a model antigen, high selectivity and sub-picomolar detection limit with a dynamic range exceeding 4 orders of magnitude is demonstrated in physiological solutions. The presented immunoassay is fast, label-free, does not require any sample pre-treatment or washing steps. Full article
Open AccessProceedings Highly Stable PEDOT:PSS Coating on Gold Microelectrodes with Improved Charge Injection Capacity for Chronic Neural Stimulation
Proceedings 2017, 1(4), 492; doi:10.3390/proceedings1040492
Published: 25 August 2017
PDF Full-text (1185 KB)
Abstract
This study introduces two new processes that highly enable PEDOT:PSS (poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)) as stable coating material for chronic neural stimulation. In first process, strong mechanical bonding between PEDOT:PSS coating and gold electrodes is achieved by creating rough porous surface with partial iodine etching. PEDOT:PSS
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This study introduces two new processes that highly enable PEDOT:PSS (poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)) as stable coating material for chronic neural stimulation. In first process, strong mechanical bonding between PEDOT:PSS coating and gold electrodes is achieved by creating rough porous surface with partial iodine etching. PEDOT:PSS coating on iodine etched gold electrode shows 100% stability under strong ultrasonic treatment. The second process represents electrochemical modification of PEDOT:PSS coating by cyclic voltammetry method in Ringer’s solution. This process reduces electrode polarization 33% during stimulation. Therefore, charge injection capacity increases that ensures safe stimulation. A combination of both processes facilitates the use of PEDOT:PSS coating for successful chronic neural recording and stimulation. Full article
Open AccessProceedings A Reversible Method to Characterize the Mass Sensitivity of a 3-Dof Mode Localized Coupled Resonator under Atmospheric Pressure
Proceedings 2017, 1(4), 493; doi:10.3390/proceedings1040493
Published: 11 August 2017
PDF Full-text (800 KB)
Abstract
In this paper, for the first time, the mass sensitivity of a 3-DoF mode localized electrostatic coupled resonator was characterized under atmospheric pressure. A reversible method was used in which nanoparticles are added on and removed from one resonator of the 3-DOF coupled
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In this paper, for the first time, the mass sensitivity of a 3-DoF mode localized electrostatic coupled resonator was characterized under atmospheric pressure. A reversible method was used in which nanoparticles are added on and removed from one resonator of the 3-DOF coupled resonator system. Besides, a comparison of three mass sensitivity characterization methods was carried out: resonance frequency shift, amplitude change and resonance vibration amplitude ratio. The results show that a 3-DOF mode localized coupled resonator has potential to be employed for biosensing applications. Full article
Open AccessProceedings Multimodal Neuroimaging Microtool for Infrared Optical Stimulation, Thermal Measurements and Recording of Neuronal Activity in the Deep Tissue
Proceedings 2017, 1(4), 494; doi:10.3390/proceedings1040494
Published: 25 August 2017
PDF Full-text (570 KB)
Abstract
Infrared neural stimulation (INS) uses pulsed near-infrared light to generate highly controlled temperature transients in neurons, leading them to fire action potentials. Stimulation of the superficial layer of the intact brain has been presented, however, the stimulation of the deep neural tissue has
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Infrared neural stimulation (INS) uses pulsed near-infrared light to generate highly controlled temperature transients in neurons, leading them to fire action potentials. Stimulation of the superficial layer of the intact brain has been presented, however, the stimulation of the deep neural tissue has larger potential in view of therapeutic use. To reveal the underlying mechanism of deep tissue stimulation properly, we present the design, the fabrication scheme and functional testing of a novel, multimodal microelectrode for future INS experiments. Three modalities—electrophysiological recording, thermal measurements and infrared waveguiding abil—were integrated based on silicon MEMS technology. Due to the advanced functionalities, a single probe is sufficient to determine safe stimulation parameters in vivo. As far as we know, this is the first multimodal microelectrode designed for INS studies in deep neural tissue. In this paper, the technology and results of chip-scale measurements are presented. Full article
Open AccessProceedings Fabricating a Highly Sensitive QCM Sensor Using AAO Nanoholes and Its Application for Biosensing
Proceedings 2017, 1(4), 495; doi:10.3390/proceedings1040495
Published: 9 August 2017
PDF Full-text (595 KB)
Abstract
A nanostructure composed of Anodic Aluminum Oxide (AAO) was obtained on an electrode of a quartz crystal microbalance (QCM) chip by anodizing Al thin film in an oxalic acid solution. The effective surface area was expanded by these nanostructures. Several morphologies were observed
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A nanostructure composed of Anodic Aluminum Oxide (AAO) was obtained on an electrode of a quartz crystal microbalance (QCM) chip by anodizing Al thin film in an oxalic acid solution. The effective surface area was expanded by these nanostructures. Several morphologies were observed under various anodic conditions by using scanning electron microscopy (SEM). We demonstrated that a QCM chip with the AAO was effective in biosensing because of its large surface area. The frequency shift corresponding to an antigen-antibody reaction improved on the nanostructured electrode compared with a flat surface electrode. Full article
Open AccessProceedings Silicon Nanowires Based Resistors for Bacteria Detection
Proceedings 2017, 1(4), 496; doi:10.3390/proceedings1040496
Published: 28 August 2017
PDF Full-text (1358 KB)
Abstract
Silicon nanowires (SiNWs) based resistors used as bacteria sensors are fabricated using the classical silicon technologies. SiNWs are grown by vapor liquid solid (VLS) method using gold as catalyst. Electrodes of the device are made of heavily in-situ doped polycristalline silicon. Results show
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Silicon nanowires (SiNWs) based resistors used as bacteria sensors are fabricated using the classical silicon technologies. SiNWs are grown by vapor liquid solid (VLS) method using gold as catalyst. Electrodes of the device are made of heavily in-situ doped polycristalline silicon. Results show potential use of the corresponding resistors, with SiNWs as sensitive units, for bacteria detection. Bacteria are preferentially hanged into SiNWs array and electrical resistance of the device decreases due to the presence of bacteria. Such resistors are promising bacteria sensors to monitor contamination in controlled environment for hygiene, fabricated in a simple and low-cost fabrication technology. Full article
Open AccessProceedings A Tubing-Free, Microfluidic Platform for the Realization of Physiologically Relevant Dosing Curves on Cellular Models
Proceedings 2017, 1(4), 497; doi:10.3390/proceedings1040497
Published: 5 September 2017
PDF Full-text (1087 KB)
Abstract
We present a microfluidic tilting platform with gravity-driven flow that enables culturing of three-dimensional microtissues under in vivo-like drug dosing regimens. In contrast to traditional, constant dosing regimens, the chip allows for gradual changes in substance concentrations. Dosing gradients are generated through an
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We present a microfluidic tilting platform with gravity-driven flow that enables culturing of three-dimensional microtissues under in vivo-like drug dosing regimens. In contrast to traditional, constant dosing regimens, the chip allows for gradual changes in substance concentrations. Dosing gradients are generated through an asymmetric Y-junction of microfluidic channels of different widths. Changes in the chip operation parameters, e.g., different tilting angles, enable to alter the drug dosage on demand. The concentration changes over time matched the predicted values, and preformed microtissues could be cultured in the chip system for at least 24 h. The chip represents an easy-to-handle tool for toxicity and efficacy testing of transient drug concentrations changes. Full article
Open AccessProceedings Flow-Ratio Monitoring in a Microchannel by Liquid-Liquid Interface Interferometry
Proceedings 2017, 1(4), 498; doi:10.3390/proceedings1040498
Published: 30 August 2017
PDF Full-text (1193 KB)
Abstract
A new method to monitor the relative flow rates of two different liquids in a microchannel is presented. By using a simple out-of-plane interferometer setup, shifts in the position of the interface between the two liquids can be determined. This label-free and real-time
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A new method to monitor the relative flow rates of two different liquids in a microchannel is presented. By using a simple out-of-plane interferometer setup, shifts in the position of the interface between the two liquids can be determined. This label-free and real-time approach to observe the interface position yields the ratio of the flow rates. Applying an out-of-plane geometry allows the use of a flexible setup of chip-external optical components such as a laser and an image sensor, which is an advantage over fixed in-plane optics. With this measurement method we are able to monitor a change of about 1% of the relative flow rate between two fluidic inlets. Full article
Open AccessProceedings Pericellular Oxygen Monitoring during Low-Level Light Therapy in Cell Culture Using a Microsensor System
Proceedings 2017, 1(4), 499; doi:10.3390/proceedings1040499
Published: 21 August 2017
PDF Full-text (1590 KB)
Abstract
An electrochemical microsensor system to monitor the pericellular oxygen concentration of fibroblasts during low-level light therapy in vitro was developed. The system provides in-sight into the metabolism of the cells during and in consequence of illumination with visible red light. This approach is
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An electrochemical microsensor system to monitor the pericellular oxygen concentration of fibroblasts during low-level light therapy in vitro was developed. The system provides in-sight into the metabolism of the cells during and in consequence of illumination with visible red light. This approach is a unique method for real-time investigations of cellular respiration during light therapy. The presented sensor system features direct amperometric measurements by using chronoamperometric protocols for long-term stability. The oxygen measurements do not show a disturbance by light. Full article
Open AccessProceedings Electrochemiluminscence Based Biosensors with AuNP Showing Catalytic ROS Generation
Proceedings 2017, 1(4), 500; doi:10.3390/proceedings1040500
Published: 28 August 2017
PDF Full-text (517 KB)
Abstract
Electrochemiluminescence (ECL) has been a useful analytical tool for fields such as molecular biology, food analysis, and analytical chemistry. In situ generation of reactive oxygen species (ROS) by surface mediated catalysis works collaboratively with the luminol based ECL system. This work describes an
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Electrochemiluminescence (ECL) has been a useful analytical tool for fields such as molecular biology, food analysis, and analytical chemistry. In situ generation of reactive oxygen species (ROS) by surface mediated catalysis works collaboratively with the luminol based ECL system. This work describes an ECL strategy involving in situ ROS generation from the surface of gold nanoparticles (AuNP). We reported on a novel condition to induce AuNP catalysis, and examined the application of this phenomenon to an immunosensing platform based on AuNP catalysis and ECL. Full article
Open AccessProceedings Stretchable Material for Microfluidic Applications
Proceedings 2017, 1(4), 501; doi:10.3390/proceedings1040501
Published: 18 August 2017
PDF Full-text (676 KB)
Abstract
Materials selected for microfluidic technology exhibit mechanical properties that can be a source of innovation. For instance, devices that take advantage of rigid (glass, silicon) or soft (elastomer, PDMS) materials, as well as porous materials, such as paper, are widely reported in the
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Materials selected for microfluidic technology exhibit mechanical properties that can be a source of innovation. For instance, devices that take advantage of rigid (glass, silicon) or soft (elastomer, PDMS) materials, as well as porous materials, such as paper, are widely reported in the literature. In this paper, we illustrate the potentialities of hyper elastic materials for lab-on-chip developments. Two breakthrough examples are reported: (i) a new digital microfluidics approach based on a stretchable membrane for addressing a large range of liquid volumes in complex protocols and (ii) a new low-cost approach for prototyping fully deformable microfluidic devices based on a polymeric foam. Full article
Open AccessProceedings Multiphysics Probe for Deep Brain Monitoring of Glioblastoma Environment
Proceedings 2017, 1(4), 502; doi:10.3390/proceedings1040502
Published: 17 August 2017
PDF Full-text (605 KB)
Abstract
This work reports on the development, and preliminary results of a multiphysics probe for deep brain monitoring of neurotransmitters and metabolites in the glioblastoma environment. We made the proof of the concept of our probe with common mice glioblastoma cells GL261 modified with
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This work reports on the development, and preliminary results of a multiphysics probe for deep brain monitoring of neurotransmitters and metabolites in the glioblastoma environment. We made the proof of the concept of our probe with common mice glioblastoma cells GL261 modified with Green Fluorescent Protein. A silicon probe with a platinum electrode at the tip was functionalized with an enzyme in order to detect, for example, Glucose, D-serine, Lactate or Glutamate. In addition, an optical fiber was inserted in a groove in the middle of the probe for light excitation and detection of glioblastoma cells by fluorescence. Full article
Open AccessProceedings Detection of Aβ(1-40) Protein in Human Serum as a Causative Agent of Alzheimer’s Disease by Strain Gauge Cantilever Biosensor Immobilizing Liposome Incorporating Cholesterol
Proceedings 2017, 1(4), 503; doi:10.3390/proceedings1040503
Published: 7 September 2017
PDF Full-text (719 KB)
Abstract
We have successfully measured amyloid beta (Aβ) (1-40) protein added in human serum by a NiCr strain gauge cantilever biosensor immobilized with liposomes incorporating cholesterol. Importantly, we investigated the effect of incorporation of cholesterol in the liposome in order to suppress the interaction
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We have successfully measured amyloid beta (Aβ) (1-40) protein added in human serum by a NiCr strain gauge cantilever biosensor immobilized with liposomes incorporating cholesterol. Importantly, we investigated the effect of incorporation of cholesterol in the liposome in order to suppress the interaction between the liposome and many different proteins included in human serum. It was revealed that incorporating cholesterol suppresses the interaction between the proteins other than Aβ in human serum and the liposome. Finally, we detected Aβ(1-40) in human serum with typical chronological behaviors due to Aβ aggregation and fibrillization. Furthermore, as a digital low-pass filtering procedure could reduce external noises, the cantilever sensor immobilized with liposome incorporating cholesterol can detect low-concentrated Aβ in human serum. Full article
Open AccessProceedings In Situ Generation of Substrate via Bi-Potential Screen-Printed Electrode for Determination of Antioxidant Using Electrochemiluminescence
Proceedings 2017, 1(4), 504; doi:10.3390/proceedings1040504
Published: 25 August 2017
PDF Full-text (618 KB)
Abstract
Excess generation of reactive oxygen species (ROS) could trigger a number of human diseases. We focused that antioxidants in beverages suppress the effect of ROS. Electrochemiluminescence (ECL) was determined by newly designed bi-potential screen printed electrodes and electron multiplying charge coupled device (EM-CCD)
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Excess generation of reactive oxygen species (ROS) could trigger a number of human diseases. We focused that antioxidants in beverages suppress the effect of ROS. Electrochemiluminescence (ECL) was determined by newly designed bi-potential screen printed electrodes and electron multiplying charge coupled device (EM-CCD) camera. Luminol based ECL was quenched due to the consumption of ROS by the antioxidants. Rapid and sensitive detection of antioxidants such as ascorbic acid and chlorogenic acid were demonstrated in beverage samples.
Full article
Open AccessProceedings Field-Effect Biosensors Modified with Tobacco Mosaic Virus Nanotubes as Enzyme Nanocarrier
Proceedings 2017, 1(4), 505; doi:10.3390/proceedings1040505
Published: 8 August 2017
PDF Full-text (739 KB)
Abstract
A new concept for the development of semiconductor field-effect biosensors by modification of a gate surface with tobacco mosaic virus (TMV) nanotubes, serving as enzyme nanocarrier, is presented. TMV nanotubes enable an immobilization of a high amount of enzymes without substantial loss of
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A new concept for the development of semiconductor field-effect biosensors by modification of a gate surface with tobacco mosaic virus (TMV) nanotubes, serving as enzyme nanocarrier, is presented. TMV nanotubes enable an immobilization of a high amount of enzymes without substantial loss of their activity, resulting in an enhanced biosensor performance. This approach has been experimentally demonstrated by realizing a capacitive field-effect penicillin biosensor using TMV nanotubes functionalized with the enzyme penicillinase as model system. Full article
Open AccessProceedings Detection of Adrenaline Based on Bioelectrocatalytical System to Support Tumor Diagnostic Technology
Proceedings 2017, 1(4), 506; doi:10.3390/proceedings1040506
Published: 7 August 2017
PDF Full-text (385 KB)
Abstract
An amperometric biosensor based on the bioelectrocatalytic measurement principle for the detection of adrenaline has been developed. The adrenaline sensor has been prepared by modification of a platinum thin-film electrode with a pyrroloquinoline quinone-dependent glucose dehydrogenase. The enzyme was immobilized via cross-linking method.
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An amperometric biosensor based on the bioelectrocatalytic measurement principle for the detection of adrenaline has been developed. The adrenaline sensor has been prepared by modification of a platinum thin-film electrode with a pyrroloquinoline quinone-dependent glucose dehydrogenase. The enzyme was immobilized via cross-linking method. Lower detection limit of 1 nM of adrenaline has been achieved by measuring at physiological level at pH 7.4. Full article
Open AccessProceedings Optical Feedback Interferometry Flowmetry Sensor in Microfluidics Chip