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Sample records for mem gas sensor

  1. Ultra-Low-Power MEMS Selective Gas Sensors

    Science.gov (United States)

    Stetter, Joseph

    2012-01-01

    This innovation is a system for gas sensing that includes an ultra-low-power MEMS (microelectromechanical system) gas sensor, combined with unique electronic circuitry and a proprietary algorithm for operating the sensor. The electronics were created from scratch, and represent a novel design capable of low-power operation of the proprietary MEMS gas sensor platform. The algorithm is used to identify a specific target gas in a gas mixture, making the sensor selective to that target gas.

  2. MEMS device for mass market gas and chemical sensors

    Science.gov (United States)

    Kinkade, Brian R.; Daly, James T.; Johnson, Edward A.

    2000-08-01

    in the house. Internet grocery delivery services could check for spoiled foods in their clients' refrigerators. City emissions regulators could monitor the various emissions sources throughout the area from their desk to predict how many pollution vouchers they will need to trade in the next week. We describe a new component architecture for mass-market sensors based on silicon microelectromechanical systems (MEMS) technology. MEMS are micrometer-scale devices that can be fabricated as discrete devices or large arrays, using the technology of integrated circuit manufacturing. These new photonic bandgap and MEMS fabricataion technologies will simplify the component technology to provide high-quality gas and chemical sensors at consumer prices.

  3. Ultra-Low-Power MEMS Selective Gas Sensors, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — KWJ offers this proposal for a very low power but very practical "nano-watt" MEMS sensor platform for NASA requirements. The proposed nano-sensor platform is ultra...

  4. Studying the Effect of Deposition Conditions on the Performance and Reliability of MEMS Gas Sensors

    Directory of Open Access Journals (Sweden)

    Walied Moussa

    2007-03-01

    Full Text Available In this paper, the reliability of a micro-electro-mechanical system (MEMS-based gas sensor has been investigated using Three Dimensional (3D coupled multiphysics Finite Element (FE analysis. The coupled field analysis involved a two-way sequential electro- thermal fields coupling and a one-way sequential thermal-structural fields coupling. An automated substructuring code was developed to reduce the computational cost involved in simulating this complicated coupled multiphysics FE analysis by up to 76 percent. The substructured multiphysics model was then used to conduct a parametric study of the MEMS-based gas sensor performance in response to the variations expected in the thermal and mechanical characteristics of thin films layers composing the sensing MEMS device generated at various stages of the microfabrication process. Whenever possible, the appropriate deposition variables were correlated in the current work to the design parameters, with good accuracy, for optimum operation conditions of the gas sensor. This is used to establish a set of design rules, using linear and nonlinear empirical relations, which can be utilized in real-time at the design and development decision-making stages of similar gas sensors to enable the microfabrication of these sensors with reliable operation.

  5. Phase Noise Squeezing Based Parametric Bifurcation Tracking of MIP-Coated Microbeam MEMS Sensor for TNT Explosive Gas Sensing

    Science.gov (United States)

    2014-06-08

    Standard Form 298 (Rev 8/98) Prescribed by ANSI Std. Z39.18 805-893-8133 W911NF-09-D-0001 Conference Proceeding 55012-LS-ICB.688 a. REPORT 14...Based Parametric Bifurcation Tracking of Mip-Coated Microbeam MEMS Sensor for TNT Explosive Gas Sensing See Attached The views, opinions and/or...2050 1 ABSTRACT Phase Noise-Squeezing-Based Parametric Bifurcation Tracking of Mip-Coated Microbeam MEMS Sensor for TNT Explosive Gas Sensing

  6. Wireless MEMs BioSensor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Crossfield is proposing to develop a low cost, single chip plant bio-monitor using an embedded MEMs based infrared (IR) spectroscopy gas sensor for carbon dioxide...

  7. Wireless MEMs BioSensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Crossfield is proposing to develop a low cost, single chip plant bio-monitor using an embedded MEMs based infrared (IR) spectroscopy gas sensor for carbon dioxide...

  8. Automotive Sensors and MEMS Technology

    Science.gov (United States)

    Nonomura, Yutaka

    - Automotive sensors are used for emission gas purification, energy conservation, car kinematic performance, safety and ITS (intelligent transportation system). The comparison of the sensor characteristics was made for their application area. Many kinds of the principles are applied for the sensors. There are two types of sensors, such as physical and chemical one. Many of the automotive sensors are physical type such as mechanical sensors. And a gas sensor is a chemical type. The sensors have been remarkably developed with the advancement of the MEMS (Micro Electro Mechanical Systems) technology. In this paper, gas, pressure, combustion pressure, acceleration, magnetic, and angular rate sensors for automotive use are explained with their features. The sensors are key devices to control cars in the engine, power train, chassis and safety systems. The environment resistance, long term reliability, and low cost are required for the automotive sensors. They are very hard to be resolved. However, the sensor technology contributes greatly to improving global environment, energy conservation, and safety. The applications of automotive sensors will be expanded with the automobile developments.

  9. Research and Development of Non-Spectroscopic MEMS-Based Sensor Arrays for Targeted Gas Detection

    Energy Technology Data Exchange (ETDEWEB)

    Loui, A; McCall, S K

    2011-10-24

    The ability to monitor the integrity of gas volumes is of interest to the stockpile surveillance community. Specifically, the leak detection of noble gases, at relevant concentration ranges and distinguished from other chemical species that may be simultaneously present, is particularly challenging. Aside from the laboratory-based method of gas chromatography-mass spectrometry (GC-MS), where samples may be collected by solid-phase microextraction (SPME) or cryofocusing, the other major approaches for gas-phase detection employ lasers typically operating in the mid-infrared wavelength region. While mass spectrometry can readily detect noble gases - the helium leak detector is an obvious example - laser-based methods such as infrared (IR) or Raman spectroscopy are completely insensitive to them as their monatomic nature precludes a non-zero dipole moment or changes in polarizability upon excitation. Therefore, noble gases can only be detected by one of two methods: (1) atomic emission spectroscopies which require the generation of plasmas through laser-induced breakdown, electrical arcing, or similar means; (2) non-spectroscopic methods which measure one or more physical properties (e.g., mass, thermal conductivity, density). In this report, we present our progress during Fiscal Year 2011 (FY11) in the research and development of a non-spectroscopic method for noble gas detection. During Fiscal Year 2010 (FY10), we demonstrated via proof-of-concept experiments that the combination of thermal conductivity detection (TCD) and coating-free damped resonance detection (CFDRD) using micro-electromechanical systems (MEMS) could provide selective sensing of these inert species. Since the MEMS-based TCD technology was directly adapted from a brassboard prototype commissioned by a previous chemical sensing project, FY11 efforts focused on advancing the state of the newer CFDRD method. This work, guided by observations previously reported in the open literature, has not only

  10. Precise Measurement of Gas Volumes by Means of Low-Offset MEMS Flow Sensors with μL/min Resolution.

    Science.gov (United States)

    Piotto, Massimo; Del Cesta, Simone; Bruschi, Paolo

    2017-10-31

    Experiments devoted to evaluate the performance of a MEMS thermal flow sensor in measuring gas volumes are described. The sensor is a single-chip platform, including several sensing structures and a low-offset, low-noise readout interface. A recently proposed offset compensation approach is implemented obtaining low temperature drift and excellent long time stability. The sensor is fabricated by applying a simple micromachining procedure to a chip produced using the BCD6s process of STMicroelectronics. Application of a gas conveyor allowed inclusion of the sensing structure into a channel of sub-millimeter cross-section. The results of measurements performed by making controlled air volumes pass through the sensor channel in both directions at rates from 0.1 to 5 mL/min are described.

  11. Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection

    KAUST Repository

    Bouchaala, Adam M.

    2016-05-25

    The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF), namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming.

  12. MEMS Bragg grating force sensor

    DEFF Research Database (Denmark)

    Reck, Kasper; Thomsen, Erik Vilain; Hansen, Ole

    2011-01-01

    We present modeling, design, fabrication and characterization of a new type of all-optical frequency modulated MEMS force sensor based on a mechanically amplified double clamped waveguide beam structure with integrated Bragg grating. The sensor is ideally suited for force measurements in harsh...... environments and for remote and distributed sensing and has a measured sensitivity of -14 nm/N, which is several times higher than what is obtained in conventional fiber Bragg grating force sensors. © 2011 Optical Society of America....

  13. Active mems microbeam device for gas detection

    KAUST Repository

    Bouchaala, Adam M.

    2017-10-05

    Sensors and active switches for applications in gas detection and other fields are described. The devices are based on the softening and hardening nonlinear response behaviors of microelectromechanical systems (MEMS) clamped-clamped microbeams. In that context, embodiments of gas-triggered MEMS microbeam sensors and switches are described. The microbeam devices can be coated with a Metal-Organic Framework to achieve high sensitivity. For gas sensing, an amplitude-based tracking algorithm can be used to quantify an amount of gas captured by the devices according to frequency shift. Noise analysis is also conducted according to the embodiments, which shows that the microbeam devices have high stability against thermal noise. The microbeam devices are also suitable for the generation of binary sensing information for alarming, for example.

  14. Nonlinear-Based MEMS Sensors and Active Switches for Gas and Acceleration Applications

    KAUST Repository

    Younis, Mohammad I.

    2016-11-25

    In this talk, we demonstrate the realization of smart sensors and actuators through the exploitation of principles of nonlinear dynamics at the micro scale. Specifically, we demonstrate combining sensing and actuation into a single device through what is called smart switches triggered by the detection of a desirable physical quantity. The concept aims to reduce the complexity of systems that rely on controllers and complex algorithms to realize on-demand trigger actions. In the first part of the talk, we discuss the category of switches triggered by the detection of gas. Toward this, electrostatically microbeams resonators are fabricated, then coated with highly absorbent polymers (MOFs), and afterward are exposed to gases. Such devices can be useful for instant alarming of toxic gases. In the second part, we demonstrate switches triggered by shock and acceleration. The concept is demonstrated on a millimeter-scale capacitive sensor. The sensor is tested using acceleration generated from shakers. Such devices can be used for the deployment of airbags in automobiles.

  15. MEMS optical sensor

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention relates to an all-optical sensor utilizing effective index modulation of a waveguide and detection of a wavelength shift of reflected light and a force sensing system accommodating said optical sensor. One embodiment of the invention relates to a sensor system comprising...... at least one multimode light source, one or more optical sensors comprising a multimode sensor optical waveguide accommodating a distributed Bragg reflector, at least one transmitting optical waveguide for guiding light from said at least one light source to said one or more multimode sensor optical...... waveguides, a detector for measuring light reflected from said Bragg reflector in said one or more multimode sensor optical waveguides, and a data processor adapted for analyzing variations in the Bragg wavelength of at least one higher order mode of the reflected light....

  16. Direction Finding Using Multiple MEMS Acoustic Sensors

    Science.gov (United States)

    2015-09-01

    MEMS ACOUSTIC SENSORS by Daniel Wilmott September 2015 Thesis Advisor: Gamani Karunasiri Co-Advisor: Fabio Alves THIS PAGE INTENTIONALLY LEFT......resonance over an angular range of 120° with a maximum uncertainty of 3.4°. 14. SUBJECT TERMS MEMS , direction finding, Ormia ochracea, acoustic sensor

  17. MEMS direction finding acoustic sensor

    Science.gov (United States)

    Karunasiri, Gamani; Alves, Fabio; Swan, William

    2017-06-01

    Conventional directional sound sensing systems employ an array of spatially separated microphones to achieve directivity. However, there are insects such as the Ormia ochracea fly that can determine the direction of sound using a miniature hearing organ much smaller than the wavelength of sound it detects. The fly's eardrums are coupled mechanically with a separation of only 0.5 mm and yet have a remarkable sensitivity to the direction of sound. The MEMS based sensor mimicking the fly's hearing system was fabricated using an SOI substrate with a 25 μm device layer. The sensor consists of two 1.5 mm x1.6 mm wings connected in the middle by a 2.7 mm x 30 μm bridge. The entire structure is connected to the substrate by two torsional legs at the center. The frequency response of the sensor showed two resonance frequencies at approximately 1.1 kHz (rocking) and 1.5 kHz (bending). The resonance at 1.1 kHz is due to rocking of the wings by twisting the legs and the other at 1.5 kHz is due to bending of the bridge. The response of the sensor was probed electronically using comb finger capacitors integrated to the edges of the wings and with the help of an MS3110 chip. A peak output voltage of about 9V/Pa was measured for sound incident normal to the device at the resonance frequency of the bending mode. The bearing of the incident sound under these conditions could be determined to within a few degrees. These findings indicate the potential use of the MEMS sensor to locate sound sources with high accuracy.

  18. Gas Sensor

    KAUST Repository

    Luebke, Ryan

    2015-01-22

    A gas sensor using a metal organic framework material can be fully integrated with related circuitry on a single substrate. In an on-chip application, the gas sensor can result in an area-efficient fully integrated gas sensor solution. In one aspect, a gas sensor can include a first gas sensing region including a first pair of electrodes, and a first gas sensitive material proximate to the first pair of electrodes, wherein the first gas sensitive material includes a first metal organic framework material.

  19. Cryogenic MEMS Pressure Sensor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A directly immersible cryogenic MEMS pressure sensor will be developed. Each silicon die will contain a vacuum-reference and a tent-like membrane. Offsetting thermal...

  20. MEMS Sensors and Actuators Laboratory (MSAL)

    Data.gov (United States)

    Federal Laboratory Consortium — The MEMS Sensors and Actuators Laboratory (MSAL) in the A.J. Clark School of Engineering at the University of Maryland (UMD) was established in January 2000. Our lab...

  1. MEMS Piezoresistive Pressure Sensor: A Survey

    OpenAIRE

    Shwetha Meti; Kirankumar B. Balavald; B. G. Sheeparmatti

    2016-01-01

    Piezoresistive pressure sensors are one of the very first products of MEMS technology, and are used in various fields like automotive industries, aerospace, biomedical applications, and household appliances. Amongst various transduction principles of pressure sensor piezoresistive transduction mechanism is widely used. Over a decade therehas been tremendous improvement in the development of the design of piezoresistive pressure sensor starting with the invention of piezoresistance...

  2. MEMS based highly sensitive dual FET gas sensor using graphene decorated Pd-Ag alloy nanoparticles for H2 detection.

    Science.gov (United States)

    Sharma, Bharat; Kim, Jung-Sik

    2018-04-12

    A low power, dual-gate field-effect transistor (FET) hydrogen gas sensor with graphene decorated Pd-Ag for hydrogen sensing applications was developed. The FET hydrogen sensor was integrated with a graphene-Pd-Ag-gate FET (GPA-FET) as hydrogen sensor coupled with Pt-gate FET as a reference sensor on a single sensor platform. The sensing gate electrode was modified with graphene by an e-spray technique followed by Pd-Ag DC/MF sputtering. Morphological and structural properties were studied by FESEM and Raman spectroscopy. FEM simulations were performed to confirm the uniform temperature control at the sensing gate electrode. The GPA-FET showed a high sensing response to hydrogen gas at the temperature of 25~254.5 °C. The as-proposed FET H 2 sensor showed the fast response time and recovery time of 16 s, 14 s, respectively at the operating temperature of 245 °C. The variation in drain current was positively related with increased working temperature and hydrogen concentration. The proposed dual-gate FET gas sensor in this study has potential applications in various fields, such as electronic noses and automobiles, owing to its low-power consumption, easy integration, good thermal stability and enhanced hydrogen sensing properties.

  3. Vortex Anemometer Using MEMS Cantilever Sensor

    CERN Document Server

    Zylka, P; Zylka, Pawel; Modrzynski, Pawel

    2010-01-01

    This paper presents construction and performance of a novel hybrid microelectromechanical system (MEMS) vortex flowmeter. A miniature cantilever MEMS displacement sensor was used to detect frequency of vortices development. 3-mm-long silicon cantilever, protruding directly out of a trailing edge of a trapezoidal glass-epoxy composite bluff body was put into oscillatory motion by vortices shed alternately from side surfaces of the obstacle. Verified linearmeasurement range of the device extended from 5 to 22 m/s; however, it could be broadened in absence of external 50-Hz mains electrical interfering signal which required bandpass frequency-domain digital sensor signal processing. The MEMS vortex sensor proved its effectiveness in detection of semilaminar airflow velocity distribution in a 40-mm-diameter tubular pipe.

  4. MEMS wireless temperature sensor for combustion studies

    Science.gov (United States)

    Lee, Minhyeok; Kawahara, Yoshihiro; Morimoto, Kenichi; Suzuki, Yuji

    2014-11-01

    A MEMS wireless wall temperature sensor for combustion studies is proposed. Electrical resistance change in a LCR circuit is used to measure the temperature through inductive coupling the sensor coil and the read-out coil. Equivalent circuit model and 3-D electromagnetic simulation are employed to design sensor configuration. The resonant frequency is increased with increasing the resistance due to the temperature increase. The prototype sensor was successfully fabricated with MEMS technologies. The impedance phase angle shows a sharp dip at the resonant frequency, which is in good accordance with the equivalent circuit model. The measured temperature sensitivity is found to be as high as 6 kHz/K, when the distance between the read-out and the sensor coils is 0.71 mm.

  5. MEMS-Based Gas Sensor Using PdO-Decorated TiO2 Thin Film for Highly Sensitive and Selective H2 Detection with Low Power Consumption

    Science.gov (United States)

    Kwak, Seungmin; Shim, Young-Seok; Yoo, Yong Kyoung; Lee, Jin-Hyung; Kim, Inho; Kim, Jinseok; Lee, Kyu Hyoung; Lee, Jeong Hoon

    2018-03-01

    We report a micromachined H2 sensor that is composed of a Pt micro-heater, low-stress insulating layer (SiO2/SiNx/SiO2), Pt-interdigitated electrodes, and gas sensing materials. Three types of Pt micro-heater are designed as function of electrode width, and their thermal properties are systematically analyzed by finite element modeling FEM with infrared camera. The power consumptions when the surface temperature reached 150, 200, 250, and 300 °C are calculated to approximately 33, 48, 67 and 85 mW, respectively. The response of the PdO nanoparticles-decorated TiO2 thin films to H2 is much higher than those of other gases such as CH4 and CO at 200 °C (48 mW). Further, the response time is reduced to approximately 3 s. The enhancement of gas sensing properties is related to well-designed micro-heater and catalytic effects of PdO nanoparticles such as electronic and chemical sensitization. These results suggest that the PdO nanoparticles-decorated TiO2 thin film, namely MEMS-based H2 sensors are very promising for use in IoT application to improve the quality of human's life.

  6. Localized Liquid-Phase Synthesis of Porous SnO2Nanotubes on MEMS Platform for Low-Power, High Performance Gas Sensors.

    Science.gov (United States)

    Cho, Incheol; Kang, Kyungnam; Yang, Daejong; Yun, Jeonghoon; Park, Inkyu

    2017-08-16

    We have developed highly sensitive, low-power gas sensors through the novel integration method of porous SnO 2 nanotubes (NTs) on a micro-electro-mechanical-systems (MEMS) platform. As a template material, ZnO nanowires (NWs) were directly synthesized on beam-shaped, suspended microheaters through an in situ localized hydrothermal reaction induced by local thermal energy around the Joule-heated area. Also, the liquid-phase deposition process enabled the formation of a porous SnO 2 thin film on the surface of ZnO NWs and simultaneous etching of the ZnO core, eventually to generate porous SnO 2 NTs. Because of the localized synthesis of SnO 2 NTs on the suspended microheater, very low power for the gas sensor operation (<6 mW) has been realized. Moreover, the sensing performance (e.g., sensitivity and response time) of synthesized SnO 2 NTs was dramatically enhanced compared to that of ZnO NWs. In addition, the sensing performance was further improved by forming SnO 2 -ZnO hybrid nanostructures due to the heterojunction effect.

  7. Optical-fiber-interconnected MEMS sensors and actuators

    Science.gov (United States)

    Miller, Michael B.; Meller, Scott A.; Wavering, Thomas A.; Greene, Jonathan A.; Murphy, Kent A.

    1998-07-01

    Microelectromechanical systems or MEMS are miniature devices that have several advantages over conventional sensing and actuating technology. MEMS devices benefit form well developed integrated circuit production methods which ensure high volume, high yield processes that create low-cost sensors and actuators. OPtical fiber interconnected MEMS will provide new functionality in MEMS devices such as multiplexed operation for distributed sensing applications. This paper presents approaches in optical fiber to MEMS interfacing and some preliminary results.

  8. Gas sensor

    Science.gov (United States)

    Schmid, Andreas K.; Mascaraque, Arantzazu; Santos, Benito; de la Figuera, Juan

    2014-09-09

    A gas sensor is described which incorporates a sensor stack comprising a first film layer of a ferromagnetic material, a spacer layer, and a second film layer of the ferromagnetic material. The first film layer is fabricated so that it exhibits a dependence of its magnetic anisotropy direction on the presence of a gas, That is, the orientation of the easy axis of magnetization will flip from out-of-plane to in-plane when the gas to be detected is present in sufficient concentration. By monitoring the change in resistance of the sensor stack when the orientation of the first layer's magnetization changes, and correlating that change with temperature one can determine both the identity and relative concentration of the detected gas. In one embodiment the stack sensor comprises a top ferromagnetic layer two mono layers thick of cobalt deposited upon a spacer layer of ruthenium, which in turn has a second layer of cobalt disposed on its other side, this second cobalt layer in contact with a programmable heater chip.

  9. MEMS Skin Friction Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Interdisciplinary Consulting Corporation proposes a sensor that offers the unique capability to make non-intrusive, direct, simultaneous mean and fluctuating shear...

  10. MEMS inertial sensors with integral rotation means.

    Energy Technology Data Exchange (ETDEWEB)

    Kohler, Stewart M.

    2003-09-01

    The state-of-the-art of inertial micro-sensors (gyroscopes and accelerometers) has advanced to the point where they are displacing the more traditional sensors in many size, power, and/or cost-sensitive applications. A factor limiting the range of application of inertial micro-sensors has been their relatively poor bias stability. The incorporation of an integral sensitive axis rotation capability would enable bias mitigation through proven techniques such as indexing, and foster the use of inertial micro-sensors in more accuracy-sensitive applications. Fabricating the integral rotation mechanism in MEMS technology would minimize the penalties associated with incorporation of this capability, and preserve the inherent advantages of inertial micro-sensors.

  11. Piezoelectric Zinc Oxide Based MEMS Acoustic Sensor

    Directory of Open Access Journals (Sweden)

    Aarti Arora

    2008-04-01

    Full Text Available An acoustic sensors exhibiting good sensitivity was fabricated using MEMS technology having piezoelectric zinc oxide as a dielectric between two plates of capacitor. Thin film zinc oxide has structural, piezoelectric and optical properties for surface acoustic wave (SAW and bulk acoustic wave (BAW devices. Oxygen effficient films are transparent and insulating having wide applications for sensors and transducers. A rf sputtered piezoelectric ZnO layer transforms the mechanical deflection of a thin etched silicon diaphragm into a piezoelectric charge. For 25-micron thin diaphragm Si was etched in tetramethylammonium hydroxide solution using bulk micromachining. This was followed by deposition of sandwiched structure composed of bottom aluminum electrode, sputtered 3 micron ZnO film and top aluminum electrode. A glass having 1 mm diameter hole was bonded on backside of device to compensate sound pressure in side the cavity. The measured value of central capacitance and dissipation factor of the fabricated MEMS acoustic sensor was found to be 82.4pF and 0.115 respectively, where as the value of ~176 pF was obtained for the rim capacitance with a dissipation factor of 0.138. The response of the acoustic sensors was reproducible for the devices prepared under similar processing conditions under different batches. The acoustic sensor was found to be working from 30Hz to 8KHz with a sensitivity of 139µV/Pa under varying acoustic pressure.

  12. MEMS Sensor Arrays for Cryogenic Propellant Applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — KWJ offers this proposal for a low-power, practical and versatile MEMS sensor platform for NASA applications. The proposed nano-sensor platform is ultra-low power...

  13. Integrated microphotonic-MEMS inertial sensors

    Science.gov (United States)

    Zandi, Kazem

    The objective of this thesis is to design, simulate, fabricate and characterize high sensitive low cost in-plane photonic-band-gap (PBG)-micro electromechanical systems (MEMS)-based miniature accelerometers and rotational rate sensors (gyroscopes) on a silicon-on-insulator (SOI) substrate in order to enable the integration of an array of two-axis of these sensors on a single SOI platform. Use of guided-wave optical devices integrated with MEMS on SOI for multichannel/multifunction sensor systems allows the use of multiple sensors to extend the measurement range and accuracy. This provides essential redundancy which makes long-term reliability in the space environment possible therefore reducing the possibility of system failure. The navigator microchip also represents the ability of accommodating diverse attitude and inertial sensors on the same microchip to eliminate the need of many separate sensors. The end product exhibits orders of magnitude reduction in system mass and size. Furthermore, redundancy improves the net performance and precision of the navigation measurement systems. Two classes of optical accelerometers/gyroscopes are considered in this thesis for application in smallsats navigation, one based on tunable Fabry-Perot (FP) filter, where the sensor is actuated by the applied acceleration providing a shift in the operating wavelength that varies linearly with the applied acceleration and the other one based on variable optical attenuator (VOA), where the sensor is actuated by the applied acceleration providing a linear change for small displacements around the waveguide propagation axis in the relative signal intensity with the applied acceleration. In the case of FP-based sensors, the FP microcavity consists of two distributed Bragg reflectors (DBR) in which one DBR mirror is attached to the proof mass of the system. As a consequence of acceleration/rotation, the relative displacement of the movable mirror with respect to the fixed mirror changes

  14. Surface activated room-temperature bonding in Ar gas ambient for MEMS encapsulation

    Science.gov (United States)

    Takagi, Hideki; Kurashima, Yuichi; Takamizawa, Akifumi; Ikegami, Takeshi; Yanagimachi, Shinya

    2018-02-01

    Surface activated room-temperature bonding of Si and sapphire wafers in high-purity inert gas ambient was examined. Although surface activated bonding has been mainly performed in high vacuum, Si and sapphire wafers were successfully bonded in Ar gas ambient up to 90 kPa, which is almost atmospheric pressure. The dicing test proved that the bonding prepared in Ar gas ambient was strong enough for MEMS packaging, although the bonding strength was slightly decreased compared with that prepared in vacuum. Transmission electron microscope observation revealed that the bonding interface prepared in Ar gas ambient is almost the same as that prepared in vacuum. It means that Ar atoms in the bonding ambient do not hamper the interatomic bond formation at the bonding interface. Room-temperature bonding in gas ambient enables hermetic packaging of MEMS devices, such as inertia sensors, MEMS switches, and Cs vapor cells for MEMS atomic clocks at various pressures.

  15. The Sandia MEMS passive shock sensor : FY07 maturation activities.

    Energy Technology Data Exchange (ETDEWEB)

    Houston, Jack E.; Blecke, Jill; Mitchell, John Anthony; Wittwer, Jonathan W.; Crowson, Douglas A.; Clemens, Rebecca C.; Walraven, Jeremy Allen; Epp, David S.; Baker, Michael Sean

    2008-08-01

    This report describes activities conducted in FY07 to mature the MEMS passive shock sensor. The first chapter of the report provides motivation and background on activities that are described in detail in later chapters. The second chapter discusses concepts that are important for integrating the MEMS passive shock sensor into a system. Following these two introductory chapters, the report details modeling and design efforts, packaging, failure analysis and testing and validation. At the end of FY07, the MEMS passive shock sensor was at TRL 4.

  16. Integrated Temperature and Hydrogen Sensors with MEMS Technology.

    Science.gov (United States)

    Jiang, Hongchuan; Huang, Min; Yu, Yibing; Tian, Xiaoyu; Zhao, Xiaohui; Zhang, Wanli; Zhang, Jianfeng; Huang, Yifan; Yu, Kun

    2017-12-31

    In this work, a PdNi thin film hydrogen gas sensor with integrated Pt thin film temperature sensor was designed and fabricated using the micro-electro-mechanical system (MEMS) process. The integrated sensors consist of two resistors: the former, based on Pt film, is used as a temperature sensor, while the latter had the function of hydrogen sensing and is based on PdNi alloy film. The temperature coefficient of resistance (TCR) in both devices was measured and the output response of the PdNi film hydrogen sensor was calibrated based on the temperature acquired by the Pt temperature sensor. The SiN layer was deposited on top of Pt film to inhibit the hydrogen diffusion and reduce consequent disturbance on temperature measurement. The TCR of the PdNi film and the Pt film was about 0.00122/K and 0.00217/K, respectively. The performances of the PdNi film hydrogen sensor were investigated with hydrogen concentrations from 0.3% to 3% on different temperatures from 294.7 to 302.2 K. With the measured temperature of the Pt resistor and the TCR of the PdNi film, the impact of the temperature on the performances of the PdNi film hydrogen sensor was reduced. The output response, response time and recovery time of the PdNi film hydrogen sensors under the hydrogen concentration of 0.5%, 1.0%, 1.5% and 2.0% were measured at 313 K. The output response of the PdNi thin film hydrogen sensors increased with increasing hydrogen concentration while the response time and recovery time decreased. A cycling test between pure nitrogen and 3% hydrogen concentration was performed at 313 K and PdNi thin film hydrogen sensor demonstrated great repeatability in the cycling test.

  17. Robust MEMS gyroscope for oil and gas exploration

    Science.gov (United States)

    Lin, David; Miller, Todd

    2014-06-01

    To satisfy the performance and reliability requirement of a MEMS based harsh environment sensor, the sensor development needs to depart from the classic method of single-discipline technology improvement. In this paper, the authors will describe a Microsystem-based design methodology which considers simultaneous multiple technology domain interaction and achieves performance optimization at the system level to address the harsh environment sensing challenge. This is demonstrated through specific examples of investigating a robust MEMS gyroscope suitable for high temperature and high vibration environments such as down-hole drilling for Oil and Gas applications. In particular, the different mechanisms of temperature-induced errors in MEMS gyroscope are discussed. The error sources include both the direct impact of the gyroscope dynamics by temperature and the indirect perturbation by temperature-induced package stress. For vibration and shock induced failure, the error contributions from the low frequency and high frequency contents are discussed. Different transducer designs with equivalent rate sensitivity can vary with several orders of magnitude in terms of the susceptibility to mechanical vibration. Also shown are the complex interactions among the gyroscopic transducer, packaging and the control electronics, resulting from these temperature and vibration error sources. The microsystem-based design methodology is able to capture such complex interactions and improve the gyroscope temperature and vibration performance. In contrast to other efforts in harsh environment sensing which focus on specific technology domains, the authors strive to demonstrate the need and advantage of addressing MEMS performance and reliability in harsh environment from a microsystem perspective.

  18. MEMS-based thermoelectric infrared sensors: A review

    Science.gov (United States)

    Xu, Dehui; Wang, Yuelin; Xiong, Bin; Li, Tie

    2017-12-01

    In the past decade, micro-electromechanical systems (MEMS)-based thermoelectric infrared (IR) sensors have received considerable attention because of the advances in micromachining technology. This paper presents a review of MEMS-based thermoelectric IR sensors. The first part describes the physics of the device and discusses the figures of merit. The second part discusses the sensing materials, thermal isolation microstructures, absorber designs, and packaging methods for these sensors and provides examples. Moreover, the status of sensor implementation technology is examined from a historical perspective by presenting findings from the early years to the most recent findings.

  19. MEMS CHIP CO2 SENSOR FOR BUILDING SYSTEMS INTEGRATION

    Energy Technology Data Exchange (ETDEWEB)

    Anton Carl Greenwald

    2005-09-14

    The objective of this research was to develop an affordable, reliable sensor to enable demand controlled ventilation (DCV). A significant portion of total energy consumption in the United States is used for heating or air conditioning (HVAC) buildings. To assure occupant safety and fresh air levels in large buildings, and especially those with sealed windows, HVAC systems are frequently run in excess of true requirements as automated systems cannot now tell the occupancy level of interior spaces. If such a sensor (e.g. thermostat sized device) were available, it would reduce energy use between 10 and 20% in such buildings. A quantitative measure of ''fresh air'' is the concentration of carbon dioxide (CO{sub 2}) present. An inert gas, CO{sub 2} is not easily detected by chemical sensors and is usually measured by infrared spectroscopy. Ion Optics research developed a complete infrared sensor package on a single MEMS chip. It contains the infrared (IR) source, IR detector and IR filter. The device resulting from this DOE sponsored research has sufficient sensitivity, lifetime, and drift rate to meet the specifications of commercial instrument manufacturers who are now testing the device for use in their building systems.

  20. Stylus type MEMS texture sensor covered with corrugated diaphragm

    Science.gov (United States)

    Tsukamoto, Takashiro; Asao, Hideaki; Tanaka, Shuji

    2017-09-01

    In this paper, a stylus type MEMS texture sensor covered with a corrugated palylene diaphragm, which prevent debris from jamming into the sensor without significant degradation of sensitivity and bandwidth, was reported. A new fabrication process using a lost-foil method to make the corrugated diaphragm on a 3-axis piezoresistive force sensor at wafer level has been developed. The texture sensor could detect the surface microstructure as small as about 10 \

  1. Design, modeling, and simulation of MEMS pressure sensors

    Science.gov (United States)

    Geca, Mateusz; Kociubiński, Andrzej

    2013-10-01

    This paper focuses on the design and analysis of a MEMS piezoresistive pressure sensor. The absolute pressure sensor with a 150μm wide and 3μm thick silicon membrane is modeled and simulated using CoventorWare™ softwareprofiting from a finite element method (FEM) implemented to determine specific electro-mechanical parameter values characterizing MEMS structure being designed. Optimization of piezoresistor parameters has been also performed to determine optimum dimensions of piezoresistors and their location referred to the center on the pressure sensor diaphragm. The output voltage measured on a piezoresistive Wheatstone bridge has been obtained and compared for two different resistor materials along with and linearity error analysis.

  2. A single-mask thermal displacement sensor in MEMS

    NARCIS (Netherlands)

    Krijnen, B.; Krijnen, B.; Hogervorst, R.P.; van Dijk, J.W.; Engelen, Johannes Bernardus Charles; Woldering, L.A.; Brouwer, Dannis Michel; Abelmann, Leon; Soemers, Herman

    2011-01-01

    This work presents a MEMS displacement sensor based on the conductive heat transfer of a resistively heated silicon structure towards an actuated stage parallel to the structure. This differential sensor can be easily incorporated into a silicon-on-insulator-based process, and fabricated within the

  3. Development of a wireless MEMS multifunction sensor system and field demonstration of embedded sensors for monitoring concrete pavements, volume II

    Science.gov (United States)

    2016-08-01

    This two-pronged study evaluated the performance of commercial off-the-shelf (COTS) micro-electromechanical sensors and systems (MEMS) embedded in concrete pavement (Final Report Volume I) and developed a wireless MEMS multifunctional sensor system f...

  4. Gas sensor

    Energy Technology Data Exchange (ETDEWEB)

    Driscoll, J.N.; Atwood, E.S.

    1987-04-21

    A method is described for detecting SO/sub 2/ gas in a gaseous or liquid sample, the method comprising testing the sample in an electrochemical cell comprising a body and within the body a detection electrode, a reference electrode, a liquid electrolyte connecting the electrodes. And a membrane permeable to the gas is in close proximity to the detection electrode and arranged to separate the electrodes and the electrolyte from the sample, the liquid electrolyte being an aqueous buffer solution buffered to a pH value of between 6.0 and 7.2 and being initially essentially free of any salt capable of dissociating to form in the electrolyte HSO/sub 3/ or SO/sub 3/. The electrolyte contains at least 25% v/v of a water miscible solvent having a dielectric constant of at least 10 and being non-interfering with the detection and reference electrodes. The testing comprises measuring a change in potential between the reference electrode and the detection electrode.

  5. Advantages of PZT thick film for MEMS sensors

    DEFF Research Database (Denmark)

    Hindrichsen, Christian Carstensen; Lou-Moller, R.; Hansen, K.

    2010-01-01

    For all MEMS devices a high coupling between the mechanical and electrical domain is desired. Figures of merit describing the coupling are important for comparing different piezoelectric materials. The existing figures of merit are discussed and a new figure of merit is introduced for a fair...... comparison of piezoelectric thin and thick films based MEMS devices, as cantilevers, beams, bridges and membranes. Simple analytical modeling is used to define the new figure of merit. The relevant figure of merits is compared for the piezoelectric material of interest for MEMS applications: ZnO, AIN, PZT....... Improved figure of merit is reached in the piezoelectric PZT thick film, TF2100CIP, by using cold isostatic pressure in the PZT preparation process. The porosity of TF2100 is decreased 38%, hence, allowing an increase of charge sensitivity for MEMS sensors of 59%....

  6. MEMS capacitive force sensors for cellular and flight biomechanics

    International Nuclear Information System (INIS)

    Sun Yu; Nelson, Bradley J

    2007-01-01

    Microelectromechanical systems (MEMS) are playing increasingly important roles in facilitating biological studies. They are capable of providing not only qualitative but also quantitative information on the cellular, sub-cellular and organism levels, which is instrumental to understanding the fundamental elements of biological systems. MEMS force sensors with their high bandwidth and high sensitivity combined with their small size, in particular, have found a role in this domain, because of the importance of quantifying forces and their effect on the function and morphology of many biological structures. This paper describes our research in the development of MEMS capacitive force sensors that have already demonstrated their effectiveness in the areas of cell mechanics and Drosophila flight dynamics studies. (review article)

  7. From MEMS to NEMS : Scaling Cantilever Sensors

    NARCIS (Netherlands)

    Yang, C.K.

    2012-01-01

    This thesis studies the effects of scaling on the characterisation and readout of micro-electro mechanical systems (MEMS) to nano-electro mechanical systems (NEMS). In particular it focuses on cantilever, which is a basic device building block and an important transducer in many sensing

  8. Design of the MEMS Piezoresistive Electronic Heart Sound Sensor

    Directory of Open Access Journals (Sweden)

    Guojun Zhang

    2016-11-01

    Full Text Available This paper proposes the electronic heart sound sensor, based on the piezoresistive principle and MEMS (Micro-Electro-Mechanical System technology. Firstly, according to the characteristics of heart sound detection, the double-beam-block microstructure has been proposed, and the theoretical analysis and finite element method (FEM simulation have been carried out. Combined with the natural frequency response of the heart sound (20~600 Hz, its structure sizes have been determined. Secondly, the processing technology of the microstructure with the stress concentration grooves has been developed. The material and sizes of the package have been determined by the three-layer medium transmission principle. Lastly, the MEMS piezoresistive electronic heart sound sensor has been tested compared with the 3200-type electronic stethoscope from 3M (São Paulo, MN, USA. The test results show that the heart sound waveform tested by the MEMS electronic heart sound sensor are almost the same as that tested by the 3200-type electronic stethoscope. Moreover, its signal-to-noise ratio is significantly higher. Compared with the traditional stethoscope, the MEMS heart sound sensor can provide the first and second heart sounds containing more abundant information about the lesion. Compared with the 3200-type electronic stethoscope from 3M, it has better performance and lower cost.

  9. Design of the MEMS Piezoresistive Electronic Heart Sound Sensor.

    Science.gov (United States)

    Zhang, Guojun; Liu, Mengran; Guo, Nan; Zhang, Wendong

    2016-11-07

    This paper proposes the electronic heart sound sensor, based on the piezoresistive principle and MEMS (Micro-Electro-Mechanical System) technology. Firstly, according to the characteristics of heart sound detection, the double-beam-block microstructure has been proposed, and the theoretical analysis and finite element method (FEM) simulation have been carried out. Combined with the natural frequency response of the heart sound (20~600 Hz), its structure sizes have been determined. Secondly, the processing technology of the microstructure with the stress concentration grooves has been developed. The material and sizes of the package have been determined by the three-layer medium transmission principle. Lastly, the MEMS piezoresistive electronic heart sound sensor has been tested compared with the 3200-type electronic stethoscope from 3M (São Paulo, MN, USA). The test results show that the heart sound waveform tested by the MEMS electronic heart sound sensor are almost the same as that tested by the 3200-type electronic stethoscope. Moreover, its signal-to-noise ratio is significantly higher. Compared with the traditional stethoscope, the MEMS heart sound sensor can provide the first and second heart sounds containing more abundant information about the lesion. Compared with the 3200-type electronic stethoscope from 3M, it has better performance and lower cost.

  10. A single-mask thermal displacement sensor in MEMS

    NARCIS (Netherlands)

    Hogervorst, R.P.; Krijnen, B.; Krijnen, B.; Brouwer, Dannis Michel; Engelen, Johannes Bernardus Charles; Staufer, U.

    Position sensing in MEMS is often based on the principle of varying capacitance [1]. Alternative position sensing principles include using integrated optical waveguides [2] or varying thermal conductance [3]. Lantz et al demonstrated a thermal displacement sensor achieving nanometre resolution on a

  11. New Trends on MEMS Sensor Technology for Harsh Environment Applications

    Directory of Open Access Journals (Sweden)

    Patricia M. NIEVA

    2007-10-01

    Full Text Available MEMS and NEMS sensor systems that can operate in the presence of high temperatures, corrosive media, and/or high radiation hold great promise for harsh environment applications. They would reduce weight, improve machine reliability and reduce cost in strategic market sectors such as automotive, avionics, oil well logging, and nuclear power. This paper presents a review of the recent advances in harsh-environment MEMS and NEMS sensors focusing on materials and devices. Special emphasis is put on high-temperature operation. Wide-bandgap semiconductor materials for high temperature applications are discussed from the device point of view. Micro-opto mechanical systems (MOEMS are presented as a new trend for high temperature applications. As an example of a harsh environment MOEMS sensor, a vibration sensor is presented.

  12. Poly-SiGe for MEMS-above-CMOS sensors

    CERN Document Server

    Gonzalez Ruiz, Pilar; Witvrouw, Ann

    2014-01-01

    Polycrystalline SiGe has emerged as a promising MEMS (Microelectromechanical Systems) structural material since it provides the desired mechanical properties at lower temperatures compared to poly-Si, allowing the direct post-processing on top of CMOS. This CMOS-MEMS monolithic integration can lead to more compact MEMS with improved performance. The potential of poly-SiGe for MEMS above-aluminum-backend CMOS integration has already been demonstrated. However, aggressive interconnect scaling has led to the replacement of the traditional aluminum metallization by copper (Cu) metallization, due to its lower resistivity and improved reliability. Poly-SiGe for MEMS-above-CMOS sensors demonstrates the compatibility of poly-SiGe with post-processing above the advanced CMOS technology nodes through the successful fabrication of an integrated poly-SiGe piezoresistive pressure sensor, directly fabricated above 0.13 m Cu-backend CMOS. Furthermore, this book presents the first detailed investigation on the influence o...

  13. Fiber optic gas sensor

    Science.gov (United States)

    Chen, Peng (Inventor); Buric, Michael P. (Inventor); Swinehart, Philip R. (Inventor); Maklad, Mokhtar S. (Inventor)

    2010-01-01

    A gas sensor includes an in-fiber resonant wavelength device provided in a fiber core at a first location. The fiber propagates a sensing light and a power light. A layer of a material is attached to the fiber at the first location. The material is able to absorb the gas at a temperature dependent gas absorption rate. The power light is used to heat the material and increases the gas absorption rate, thereby increasing sensor performance, especially at low temperatures. Further, a method is described of flash heating the gas sensor to absorb more of the gas, allowing the sensor to cool, thereby locking in the gas content of the sensor material, and taking the difference between the starting and ending resonant wavelengths as an indication of the concentration of the gas in the ambient atmosphere.

  14. Resonant Magnetic Field Sensors Based On MEMS Technology

    Directory of Open Access Journals (Sweden)

    Elías Manjarrez

    2009-09-01

    Full Text Available Microelectromechanical systems (MEMS technology allows the integration of magnetic field sensors with electronic components, which presents important advantages such as small size, light weight, minimum power consumption, low cost, better sensitivity and high resolution. We present a discussion and review of resonant magnetic field sensors based on MEMS technology. In practice, these sensors exploit the Lorentz force in order to detect external magnetic fields through the displacement of resonant structures, which are measured with optical, capacitive, and piezoresistive sensing techniques. From these, the optical sensing presents immunity to electromagnetic interference (EMI and reduces the read-out electronic complexity. Moreover, piezoresistive sensing requires an easy fabrication process as well as a standard packaging. A description of the operation mechanisms, advantages and drawbacks of each sensor is considered. MEMS magnetic field sensors are a potential alternative for numerous applications, including the automotive industry, military, medical, telecommunications, oceanographic, spatial, and environment science. In addition, future markets will need the development of several sensors on a single chip for measuring different parameters such as the magnetic field, pressure, temperature and acceleration.

  15. Resonant Magnetic Field Sensors Based On MEMS Technology

    Science.gov (United States)

    Herrera-May, Agustín L.; Aguilera-Cortés, Luz A.; García-Ramírez, Pedro J.; Manjarrez, Elías

    2009-01-01

    Microelectromechanical systems (MEMS) technology allows the integration of magnetic field sensors with electronic components, which presents important advantages such as small size, light weight, minimum power consumption, low cost, better sensitivity and high resolution. We present a discussion and review of resonant magnetic field sensors based on MEMS technology. In practice, these sensors exploit the Lorentz force in order to detect external magnetic fields through the displacement of resonant structures, which are measured with optical, capacitive, and piezoresistive sensing techniques. From these, the optical sensing presents immunity to electromagnetic interference (EMI) and reduces the read-out electronic complexity. Moreover, piezoresistive sensing requires an easy fabrication process as well as a standard packaging. A description of the operation mechanisms, advantages and drawbacks of each sensor is considered. MEMS magnetic field sensors are a potential alternative for numerous applications, including the automotive industry, military, medical, telecommunications, oceanographic, spatial, and environment science. In addition, future markets will need the development of several sensors on a single chip for measuring different parameters such as the magnetic field, pressure, temperature and acceleration. PMID:22408480

  16. Resonant Magnetic Field Sensors Based On MEMS Technology.

    Science.gov (United States)

    Herrera-May, Agustín L; Aguilera-Cortés, Luz A; García-Ramírez, Pedro J; Manjarrez, Elías

    2009-01-01

    Microelectromechanical systems (MEMS) technology allows the integration of magnetic field sensors with electronic components, which presents important advantages such as small size, light weight, minimum power consumption, low cost, better sensitivity and high resolution. We present a discussion and review of resonant magnetic field sensors based on MEMS technology. In practice, these sensors exploit the Lorentz force in order to detect external magnetic fields through the displacement of resonant structures, which are measured with optical, capacitive, and piezoresistive sensing techniques. From these, the optical sensing presents immunity to electromagnetic interference (EMI) and reduces the read-out electronic complexity. Moreover, piezoresistive sensing requires an easy fabrication process as well as a standard packaging. A description of the operation mechanisms, advantages and drawbacks of each sensor is considered. MEMS magnetic field sensors are a potential alternative for numerous applications, including the automotive industry, military, medical, telecommunications, oceanographic, spatial, and environment science. In addition, future markets will need the development of several sensors on a single chip for measuring different parameters such as the magnetic field, pressure, temperature and acceleration.

  17. Piezoresistive and piezoelectric MEMS strain sensors for vibration detection

    Science.gov (United States)

    Kon, Stanley; Oldham, Kenn; Horowitz, Roberto

    2007-04-01

    Both piezoresistive and piezoelectric materials are commonly used to detect strain caused by structural vibrations in macro-scale structures. With the increasing complexity and miniaturization of modern mechanical systems such as hard disk drive suspensions, it is imperative to explore the performance of these strain sensors when their dimensions must shrink along with those of the host structures. The miniaturized strain sensors must remain as small as possible so as to minimum their effect on structure dynamics, yet still have acceptable sensing resolution. The performances of two types of novel micro-scale strain gage for installation on stainless steel parts are compared in this paper. Micro-fabrication processes have been developed to build polycrystalline silicon piezoresistive strain sensors on a silicon substrate, which are later bonded to a steel substrate for testing. Piezoresistor geometries are optimized to effectively increase the gage factor of piezoresistive sensors while reducing sensor size. The advantage and disadvantage of these piezoresistors are compared to those of piezoelectric sensors. Experimental results reveal that the MEMS piezoelectric sensors are able to achieve a better resolution than piezoresistors, while piezoresistors can be built in much smaller areas. Both types of the MEMS strain sensors are capable of high sensitivity measurements, subject to differing constraints.

  18. MEMS climate sensor for crops in greenhouses

    DEFF Research Database (Denmark)

    Birkelund, Karen; Jensen, Kim Degn; Højlund-Nielsen, Emil

    2010-01-01

    We have developed and fabricated a multi-sensor chip for greenhouse applications and demonstrated the functionality under controlled conditions. The sensor consists of a humidity sensor, temperature sensor and three photodiodes sensitive to blue, red and white light, respectively. The humidity...... sensor responds linearly with humidity with a full scale change of 5.6 pF. The best performing design measures a relative change of 48%. The temperature sensor responds linearly with temperature with a temperature coefficient of resistance of 3.95 x 10(-3) K-1 and a sensitivity of 26.5 Omega degrees C-1...... and humidity sensors have further been tested on plants in a greenhouse, demonstrating that individual plant behavior can be monitored....

  19. Integrated Electromechanical Transduction Schemes for Polymer MEMS Sensors

    Directory of Open Access Journals (Sweden)

    Damien Thuau

    2018-04-01

    Full Text Available Polymer Micro ElectroMechanical Systems (MEMS have the potential to constitute a powerful alternative to silicon-based MEMS devices for sensing applications. Although the use of commercial photoresists as structural material in polymer MEMS has been widely reported, the integration of functional polymer materials as electromechanical transducers has not yet received the same amount of interest. In this context, we report on the design and fabrication of different electromechanical schemes based on polymeric materials ensuring different transduction functions. Piezoresistive transduction made of carbon nanotube-based nanocomposites with a gauge factor of 200 was embedded within U-shaped polymeric cantilevers operating either in static or dynamic modes. Flexible resonators with integrated piezoelectric transduction were also realized and used as efficient viscosity sensors. Finally, piezoelectric-based organic field effect transistor (OFET electromechanical transduction exhibiting a record sensitivity of over 600 was integrated into polymer cantilevers and used as highly sensitive strain and humidity sensors. Such advances in integrated electromechanical transduction schemes should favor the development of novel all-polymer MEMS devices for flexible and wearable applications in the future.

  20. MEMS magnetic field sensor based on silicon bridge structure

    Energy Technology Data Exchange (ETDEWEB)

    Du Guangtao; Chen Xiangdong; Lin Qibin; Li Hui; Guo Huihui, E-mail: xdchen@home.swjtu.edu.c [School of Information Science and Technology, Southwest Jiaotong University, Chengdu 610031 (China)

    2010-10-15

    A MEMS piezoresistive magnetic field sensor based on a silicon bridge structure has been simulated and tested. The sensor consists of a silicon sensitivity diaphragm embedded with a piezoresistive Wheatstone bridge, and a ferromagnetic magnet adhered to the sensitivity diaphragm. When the sensor is subjected to an external magnetic field, the magnetic force bends the silicon sensitivity diaphragm, producing stress and resistors change of the Wheatstone bridge and the output voltage of the sensor. Good agreement is observed between the theory and measurement behavior of the magnetic field sensor. Experimental results demonstrate that the maximum sensitivity and minimum resolution are 48 m V/T and 160 {mu}T, respectively, making this device suitable for strong magnetic field measurement. Research results indicate that the sensor repeatability and dynamic response time are about 0.66% and 150 ms, respectively. (semiconductor devices)

  1. MEMS Skin Friction Sensor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Interdisciplinary Consulting Corporation proposes a sensor that offers the unique capability to make non-intrusive, direct, simultaneous mean and fluctuating shear...

  2. A Micro-Force Sensor with Beam-Membrane Structure for Measurement of Friction Torque in Rotating MEMS Machines

    Directory of Open Access Journals (Sweden)

    Huan Liu

    2017-10-01

    Full Text Available In this paper, a beam-membrane (BM sensor for measuring friction torque in micro-electro-mechanical system (MEMS gas bearings is presented. The proposed sensor measures the force-arm-transformed force using a detecting probe and the piezoresistive effect. This solution incorporates a membrane into a conventional four-beam structure to meet the range requirements for the measurement of both the maximum static friction torque and the kinetic friction torque in rotating MEMS machines, as well as eliminate the problem of low sensitivity with neat membrane structure. A glass wafer is bonded onto the bottom of the sensor chip with a certain gap to protect the sensor when overloaded. The comparisons between the performances of beam-based sensor, membrane-based sensor and BM sensor are conducted by finite element method (FEM, and the final sensor dimensions are also determined. Calibration of the fabricated and packaged device is experimentally performed. The practical verification is also reported in the paper for estimating the friction torque in micro gas bearings by assembling the proposed sensor into a rotary table-based measurement system. The results demonstrate that the proposed force sensor has a potential application in measuring micro friction or force in MEMS machines.

  3. Minimizing 1/f Noise in Magnetic Sensors with a MEMS Flux Concentrator

    National Research Council Canada - National Science Library

    Edelstein, A. S; Fischer, Greg; Pulskamp, Jeff; Pedersen, Michael; Bernard, William; Cheng, Shu F

    2004-01-01

    .... This shift is accomplished by modulating the magnetic field before it reaches the sensor. In our device, the magnetic sensor, a GMR sensor, is placed between flux concentrators that have been deposited on MEMS flaps...

  4. MEMS climate sensor for crops in greenhouses

    International Nuclear Information System (INIS)

    Birkelund, K; Jensen, Kim Degn; Højlund-Nielsen, Emil; Nagstrup, Johan; Lei, Anders; Petersen, Søren Dahl; Thomsen, Erik V; Andreassen, Andrea U

    2010-01-01

    We have developed and fabricated a multi-sensor chip for greenhouse applications and demonstrated the functionality under controlled conditions. The sensor consists of a humidity sensor, temperature sensor and three photodiodes sensitive to blue, red and white light, respectively. The humidity sensor responds linearly with humidity with a full scale change of 5.6 pF. The best performing design measures a relative change of 48%. The temperature sensor responds linearly with temperature with a temperature coefficient of resistance of 3.95 × 10 −3 K −1 and a sensitivity of 26.5 Ω °C −1 . The three photodiodes have been characterized and show an almost ideal diode behavior with an ideality factor of 1.27 and a series resistance of 14.9 Ω. The diodes are sensitive to blue, red and white light with the measured quantum efficiencies of 69%, 81% and 68%, respectively. The temperature and humidity sensors have further been tested on plants in a greenhouse, demonstrating that individual plant behavior can be monitored.

  5. Elastic Wave Measurement Using a MEMS AE Sensor

    Directory of Open Access Journals (Sweden)

    Takahiro Omori

    2017-07-01

    Full Text Available In recent years, with the continuing progress of aging social infrastructures such as bridges and tunnels, there has been high demand for the assessment of deterioration of their performance and conditions. Since current inspection methods for those structures have mainly relied on human resources, it is important to reduce their increasing maintenance cost. One of the key methods for achieving effective maintenance without expensive human costs is to use sensors to discriminate between healthy and unhealthy conditions. In this paper, a MEMS (micro electro mechanical systems wideband frequency sensor, which is referred to as a super acoustic (SA sensor, is evaluated through the pencil lead break (PLB test. Due to its wideband frequency characteristics, the SA sensor is expected to be a promising alternative to the existing vibration sensors, including acoustic emission (AE sensors. Several PLB signals were generated on an aluminum plate (5 mm thick, and propagating Lamb waves were detected by both AE and SA sensors. SA sensors were able to identify the location of PLB sources on the plate by measuring time differences between each sensor. By comparing the wave spectrums of both the AE and SA sensors analyzed by wavelet transform, the applicability of SA sensor for AE measurement is verified.

  6. Shock tunnel measurements of surface pressures in shock induced separated flow field using MEMS sensor array

    International Nuclear Information System (INIS)

    Sriram, R; Jagadeesh, G; Ram, S N; Hegde, G M; Nayak, M M

    2015-01-01

    Characterized not just by high Mach numbers, but also high flow total enthalpies—often accompanied by dissociation and ionization of flowing gas itself—the experimental simulation of hypersonic flows requires impulse facilities like shock tunnels. However, shock tunnel simulation imposes challenges and restrictions on the flow diagnostics, not just because of the possible extreme flow conditions, but also the short run times—typically around 1 ms. The development, calibration and application of fast response MEMS sensors for surface pressure measurements in IISc hypersonic shock tunnel HST-2, with a typical test time of 600 μs, for the complex flow field of strong (impinging) shock boundary layer interaction with separation close to the leading edge, is delineated in this paper. For Mach numbers 5.96 (total enthalpy 1.3 MJ kg −1 ) and 8.67 (total enthalpy 1.6 MJ kg −1 ), surface pressures ranging from around 200 Pa to 50 000 Pa, in various regions of the flow field, are measured using the MEMS sensors. The measurements are found to compare well with the measurements using commercial sensors. It was possible to resolve important regions of the flow field involving significant spatial gradients of pressure, with a resolution of 5 data points within 12 mm in each MEMS array, which cannot be achieved with the other commercial sensors. In particular, MEMS sensors enabled the measurement of separation pressure (at Mach 8.67) near the leading edge and the sharply varying pressure in the reattachment zone. (paper)

  7. Power for Vehicle Embedded MEMS Sensors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Embedded wireless sensors of the future will enable flight vehicle systems to be "highly aware" of onboard health and performance parameters, as well as the external...

  8. Intelligent MEMS spectral sensor for NIR applications (Conference Presentation)

    Science.gov (United States)

    Kantojärvi, Uula; Antila, Jarkko E.; Mäkynen, Jussi; Suhonen, Janne

    2017-05-01

    Near Infrared (NIR) spectrometers have been widely used in many material inspection applications, but mainly in central laboratories. The role of miniaturization, robustness of spectrometer and portability are really crucial when field inspection tools should be developed. We present an advanced spectral sensor based on a tunable Microelectromechanical (MEMS) Fabry-Perot Interferometer which will meet these requirements. We describe the wireless device design, operation principle and easy-to-use algorithms to adapt the sensor to number of applications. Multiple devices can be operated simultaneously and seamlessly through cloud connectivity. We also present some practical NIR applications carried out with truly portable NIR device.

  9. Infrared Gas Sensor

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    In recent years, the rapid development of monitoring and detecting technology of indoor air quality have been observed. We have seen the two major streams of detection technology introduced so far: Acoustic wave sensor and Infrared gas sensor. The use of a gas monitoring system in the case of that dangerous levels of gases are detected, can help to prevent an explosion or can help to prevent worker injury or exposure to toxic gases.

  10. Thermal sensors cointegrated within a MEMS thermally actuated ultrathin membrane

    International Nuclear Information System (INIS)

    Salette, A; Lefevre, R; Agraffeil, C; Guillen, J; Morfouli, P; Montès, L; Déhan, C

    2012-01-01

    This paper reports the simulation, design, fabrication and characterization of thermal sensors integrated into an ultrathin active MEMS membrane. Temperature detection is combined without any additional fabrication steps to thermal actuation. Mixing the actuation with a thermal measurement within the membrane allows us to monitor temperature during membrane deflection. Prototypes are fabricated using standard CMOS processes and a deep reactive ion etching process to release the membrane. Inner and outer actuation lead to large membrane deflection. Using such sensors, we extract the temperature profile of the thermally actuated membrane. A good fitting between finite element method simulation and characterization results validates the sensors. Finally, the optimal position of thermal sensors is extracted from this study. (paper)

  11. Virtual Fabrication of Silicon Nitride Based Multifunctional MEMS Pressure Sensor

    Directory of Open Access Journals (Sweden)

    Mahesh Kumar PATANKAR

    2011-04-01

    Full Text Available This paper shows how to combine absolute and differential pressure sensor on single silicon substrate for measuring the pressure in 0 – 1 MPa range. In this work, the sensor makes use a of silicon nitride square diaphragm supported by a thick silicon rim. Piezoresistors below the diaphragms are defined by the p+ etch stop technique and structured by the anisotropic etching in Wheatstone bridge configuration. In event of pressure, mechanical deformation occurs in the diaphragm and induces the stress in it which can be translated into electrical signal accordingly. This sensor shows the sensitivity of 142 mV/V.KPa. The pressure sensor has been designed, simulated and virtually fabricated using Intellisuite MEMS software tool. Simulation results shows that the good agreement with the analytical solutions.

  12. Microfabricated Formaldehyde Gas Sensors

    Directory of Open Access Journals (Sweden)

    Karen C. Cheung

    2009-11-01

    Full Text Available Formaldehyde is a volatile organic compound that is widely used in textiles, paper, wood composites, and household materials. Formaldehyde will continuously outgas from manufactured wood products such as furniture, with adverse health effects resulting from prolonged low-level exposure. New, microfabricated sensors for formaldehyde have been developed to meet the need for portable, low-power gas detection. This paper reviews recent work including silicon microhotplates for metal oxide-based detection, enzyme-based electrochemical sensors, and nanowire-based sensors. This paper also investigates the promise of polymer-based sensors for low-temperature, low-power operation.

  13. A Robust MEMS Based Multi-Component Sensor for 3D Borehole Seismic Arrays

    Energy Technology Data Exchange (ETDEWEB)

    Paulsson Geophysical Services

    2008-03-31

    The objective of this project was to develop, prototype and test a robust multi-component sensor that combines both Fiber Optic and MEMS technology for use in a borehole seismic array. The use such FOMEMS based sensors allows a dramatic increase in the number of sensors that can be deployed simultaneously in a borehole seismic array. Therefore, denser sampling of the seismic wave field can be afforded, which in turn allows us to efficiently and adequately sample P-wave as well as S-wave for high-resolution imaging purposes. Design, packaging and integration of the multi-component sensors and deployment system will target maximum operating temperature of 350-400 F and a maximum pressure of 15000-25000 psi, thus allowing operation under conditions encountered in deep gas reservoirs. This project aimed at using existing pieces of deployment technology as well as MEMS and fiber-optic technology. A sensor design and analysis study has been carried out and a laboratory prototype of an interrogator for a robust borehole seismic array system has been assembled and validated.

  14. Evaluation of MEMS-Based Wireless Accelerometer Sensors in Detecting Gear Tooth Faults in Helicopter Transmissions

    Science.gov (United States)

    Lewicki, David George; Lambert, Nicholas A.; Wagoner, Robert S.

    2015-01-01

    The diagnostics capability of micro-electro-mechanical systems (MEMS) based rotating accelerometer sensors in detecting gear tooth crack failures in helicopter main-rotor transmissions was evaluated. MEMS sensors were installed on a pre-notched OH-58C spiral-bevel pinion gear. Endurance tests were performed and the gear was run to tooth fracture failure. Results from the MEMS sensor were compared to conventional accelerometers mounted on the transmission housing. Most of the four stationary accelerometers mounted on the gear box housing and most of the CI's used gave indications of failure at the end of the test. The MEMS system performed well and lasted the entire test. All MEMS accelerometers gave an indication of failure at the end of the test. The MEMS systems performed as well, if not better, than the stationary accelerometers mounted on the gear box housing with regards to gear tooth fault detection. For both the MEMS sensors and stationary sensors, the fault detection time was not much sooner than the actual tooth fracture time. The MEMS sensor spectrum data showed large first order shaft frequency sidebands due to the measurement rotating frame of reference. The method of constructing a pseudo tach signal from periodic characteristics of the vibration data was successful in deriving a TSA signal without an actual tach and proved as an effective way to improve fault detection for the MEMS.

  15. Fabrication and Characterization of a CMOS-MEMS Humidity Sensor

    Science.gov (United States)

    Dennis, John-Ojur; Ahmed, Abdelaziz-Yousif; Khir, Mohd-Haris

    2015-01-01

    This paper reports on the fabrication and characterization of a Complementary Metal Oxide Semiconductor-Microelectromechanical System (CMOS-MEMS) device with embedded microheater operated at relatively elevated temperatures (40 °C to 80 °C) for the purpose of relative humidity measurement. The sensing principle is based on the change in amplitude of the device due to adsorption or desorption of humidity on the active material layer of titanium dioxide (TiO2) nanoparticles deposited on the moving plate, which results in changes in the mass of the device. The sensor has been designed and fabricated through a standard 0.35 µm CMOS process technology and post-CMOS micromachining technique has been successfully implemented to release the MEMS structures. The sensor is operated in the dynamic mode using electrothermal actuation and the output signal measured using a piezoresistive (PZR) sensor connected in a Wheatstone bridge circuit. The output voltage of the humidity sensor increases from 0.585 mV to 30.580 mV as the humidity increases from 35% RH to 95% RH. The output voltage is found to be linear from 0.585 mV to 3.250 mV as the humidity increased from 35% RH to 60% RH, with sensitivity of 0.107 mV/% RH; and again linear from 3.250 mV to 30.580 mV as the humidity level increases from 60% RH to 95% RH, with higher sensitivity of 0.781 mV/% RH. On the other hand, the sensitivity of the humidity sensor increases linearly from 0.102 mV/% RH to 0.501 mV/% RH with increase in the temperature from 40 °C to 80 °C and a maximum hysteresis of 0.87% RH is found at a relative humidity of 80%. The sensitivity is also frequency dependent, increasing from 0.500 mV/% RH at 2 Hz to reach a maximum value of 1.634 mV/% RH at a frequency of 12 Hz, then decreasing to 1.110 mV/% RH at a frequency of 20 Hz. Finally, the CMOS-MEMS humidity sensor showed comparable response, recovery, and repeatability of measurements in three cycles as compared to a standard sensor that directly

  16. Fabrication and Characterization of a CMOS-MEMS Humidity Sensor.

    Science.gov (United States)

    Dennis, John-Ojur; Ahmed, Abdelaziz-Yousif; Khir, Mohd-Haris

    2015-07-10

    This paper reports on the fabrication and characterization of a Complementary Metal Oxide Semiconductor-Microelectromechanical System (CMOS-MEMS) device with embedded microheater operated at relatively elevated temperatures (40 °C to 80 °C) for the purpose of relative humidity measurement. The sensing principle is based on the change in amplitude of the device due to adsorption or desorption of humidity on the active material layer of titanium dioxide (TiO2) nanoparticles deposited on the moving plate, which results in changes in the mass of the device. The sensor has been designed and fabricated through a standard 0.35 µm CMOS process technology and post-CMOS micromachining technique has been successfully implemented to release the MEMS structures. The sensor is operated in the dynamic mode using electrothermal actuation and the output signal measured using a piezoresistive (PZR) sensor connected in a Wheatstone bridge circuit. The output voltage of the humidity sensor increases from 0.585 mV to 30.580 mV as the humidity increases from 35% RH to 95% RH. The output voltage is found to be linear from 0.585 mV to 3.250 mV as the humidity increased from 35% RH to 60% RH, with sensitivity of 0.107 mV/% RH; and again linear from 3.250 mV to 30.580 mV as the humidity level increases from 60% RH to 95% RH, with higher sensitivity of 0.781 mV/% RH. On the other hand, the sensitivity of the humidity sensor increases linearly from 0.102 mV/% RH to 0.501 mV/% RH with increase in the temperature from 40 °C to 80 °C and a maximum hysteresis of 0.87% RH is found at a relative humidity of 80%. The sensitivity is also frequency dependent, increasing from 0.500 mV/% RH at 2 Hz to reach a maximum value of 1.634 mV/% RH at a frequency of 12 Hz, then decreasing to 1.110 mV/% RH at a frequency of 20 Hz. Finally, the CMOS-MEMS humidity sensor showed comparable response, recovery, and repeatability of measurements in three cycles as compared to a standard sensor that directly

  17. Fabrication and Characterization of a CMOS-MEMS Humidity Sensor

    Directory of Open Access Journals (Sweden)

    John-Ojur Dennis

    2015-07-01

    Full Text Available This paper reports on the fabrication and characterization of a Complementary Metal Oxide Semiconductor-Microelectromechanical System (CMOS-MEMS device with embedded microheater operated at relatively elevated temperatures (40 °C to 80 °C for the purpose of relative humidity measurement. The sensing principle is based on the change in amplitude of the device due to adsorption or desorption of humidity on the active material layer of titanium dioxide (TiO2 nanoparticles deposited on the moving plate, which results in changes in the mass of the device. The sensor has been designed and fabricated through a standard 0.35 µm CMOS process technology and post-CMOS micromachining technique has been successfully implemented to release the MEMS structures. The sensor is operated in the dynamic mode using electrothermal actuation and the output signal measured using a piezoresistive (PZR sensor connected in a Wheatstone bridge circuit. The output voltage of the humidity sensor increases from 0.585 mV to 30.580 mV as the humidity increases from 35% RH to 95% RH. The output voltage is found to be linear from 0.585 mV to 3.250 mV as the humidity increased from 35% RH to 60% RH, with sensitivity of 0.107 mV/% RH; and again linear from 3.250 mV to 30.580 mV as the humidity level increases from 60% RH to 95% RH, with higher sensitivity of 0.781 mV/% RH. On the other hand, the sensitivity of the humidity sensor increases linearly from 0.102 mV/% RH to 0.501 mV/% RH with increase in the temperature from 40 °C to 80 °C and a maximum hysteresis of 0.87% RH is found at a relative humidity of 80%. The sensitivity is also frequency dependent, increasing from 0.500 mV/% RH at 2 Hz to reach a maximum value of 1.634 mV/% RH at a frequency of 12 Hz, then decreasing to 1.110 mV/% RH at a frequency of 20 Hz. Finally, the CMOS-MEMS humidity sensor showed comparable response, recovery, and repeatability of measurements in three cycles as compared to a standard sensor that

  18. Design and characterization of in-plane MEMS yaw rate sensor

    Indian Academy of Sciences (India)

    CranesSci MEMS Laboratory, Department of Mechanical Engineering,. Indian Institute of ... In this paper, we discuss the design and characterization of a vibratory yaw rate MEMS sensor that uses ..... Patil N 2006 Design and analysis of angular rate sensors, Master's thesis, Indian Institute of Science. Polytec reference ...

  19. Design and analysis of MEMS MWCNT/epoxy strain sensor using ...

    Indian Academy of Sciences (India)

    2017-06-20

    Jun 20, 2017 ... Home; Journals; Pramana – Journal of Physics; Volume 89; Issue 1. Design and analysis of MEMS MWCNT/epoxy strain sensor using COMSOL. GAURAV ... The design and performance of piezoresistive MEMS-based MWCNT/epoxy composite strain sensor using COMSOL Multiphysics Toolbox has been ...

  20. Outlook and challenges of nano devices, sensors, and MEMS

    CERN Document Server

    Liu, Ziv

    2017-01-01

    This book provides readers with an overview of the design, fabrication, simulation, and reliability of nanoscale semiconductor devices, MEMS, and sensors, as they serve for realizing the next-generation internet of things. The authors focus on how the nanoscale structures interact with the electrical and/or optical performance, how to find optimal solutions to achieve the best outcome, how these apparatus can be designed via models and simulations, how to improve reliability, and what are the possible challenges and roadblocks moving forward.

  1. The MEMS Flux Concentrator: A Device for Minimizing 1/f Noise in Magnetic Sensors

    National Research Council Canada - National Science Library

    Edelstein, Alan

    2002-01-01

    .... Here we describe a Micro Electro-Mechanical Systems (MEMS) flux concentrator, which is a new device that can minimize 1/f noise in magnetic sensors by modulating the magnetic field at the position of the sensor...

  2. A MEMS Flow Sensor for Self-adjusted Precise Non-Contact Liquid Dispensing

    OpenAIRE

    Liu Yaxin; Zhong Ming; Yao Yufeng

    2013-01-01

    A MEMS flow sensor was proposed to enhance the reliability and accuracy of liquid dispensing system. Benefiting from the feedback of sensor information, the system can self-adjust the open time of the solenoid vale to accurately dispensing desired reagent volume without pre-calibration. This study focuses on the design, fabrication and application of this flow sensor. Firstly, the design, fabrication and characteristics of the MEMS flow sensor based on the measurement of the pressure differen...

  3. Piezoelectric MEMS sensors: state-of-the-art and perspectives

    International Nuclear Information System (INIS)

    Tadigadapa, S; Mateti, K

    2009-01-01

    Over the past two decades, several advances have been made in micromachined sensors and actuators. As the field of microelectromechanical systems (MEMS) has advanced, a clear need for the integration of materials other than silicon and its compounds into micromachined transducers has emerged. Piezoelectric materials are high energy density materials that scale very favorably upon miniaturization and that has led to an ever-growing interest in piezoelectric films for MEMS applications. At this time, piezoelectric aluminum-nitride-based film bulk acoustic resonators (FBAR) have already been successfully commercialized. Future innovations and improvements in inertial sensors for navigation, high-frequency crystal oscillators and filters for wireless applications, microactuators for RF applications, chip-scale chemical analysis systems and countless other applications hinge upon the successful miniaturization of components and integration of piezoelectrics and metals into these systems. In this article, a comprehensive review of micromachined piezoelectric transducer technology will be presented. Piezoelectric materials in bulk and thin film forms will be reviewed and fabrication techniques for the integration of these materials for microsensor applications will be presented. Recent advances in various piezoelectric microsensors will be presented through specific examples. This review will conclude with a critical assessment of the future trends and promise of this technology. (topical review)

  4. The Sandia MEMS passive shock sensor : FY08 design summary.

    Energy Technology Data Exchange (ETDEWEB)

    Walraven, Jeremy Allen; Baker, Michael Sean; Clemens, Rebecca C.; Mitchell, John Anthony; Brake, Matthew Robert; Epp, David S.; Wittwer, Jonathan W.

    2008-11-01

    This report summarizes design and modeling activities for the MEMS passive shock sensor. It provides a description of past design revisions, including the purposes and major differences between design revisions but with a focus on Revisions 4 through 7 and the work performed in fiscal year 2008 (FY08). This report is a reference for comparing different designs; it summarizes design parameters and analysis results, and identifies test structures. It also highlights some of the changes and or additions to models previously documented [Mitchell et al. 2006, Mitchell et al. 2008] such as the way uncertainty thresholds are analyzed and reported. It also includes dynamic simulation results used to investigate how positioning of hard stops may reduce vibration sensitivity.

  5. MEMS sensors and wireless telemetry for distributed systems

    Energy Technology Data Exchange (ETDEWEB)

    Britton, C.L. Jr.; Warmack, R.J.; Smith, S.F. [and others

    1998-02-01

    Selectively coated cantilevers are being developed at ORNL for chemical and biological sensing. The sensitivity can exceed that of other electro-mechanical devices as parts-per-trillion detection can be demonstrated for certain species. The authors are now proceeding to develop systems that employ electrically readable microcantilevers in a standard MEMS process and standard CMOS processes. One of their primary areas of interest is chemical sensing for environmental applications. Towards this end, they are presently developing electronic readout of a mercury-sensitive coated cantilever. In order to field arrays of distributed sensors, a wireless network for data reporting is needed. For this, the authors are developing on-chip spread-spectrum encoding and modulation circuitry to improve the robustness and security of sensor data in typical interference- and multipath-impaired environments. They have also provided for a selection of distinct spreading codes to serve groups of sensors in a common environment by the application of code-division multiple-access techniques. Most of the RF circuitry they have designed and fabricated in 0.5 {micro}m CMOS has been tested and verified operational to above 1 GHz. The initial intended operation is for use in the 915 MHz Industrial, Scientific, and Medical (ISM) band. This paper presents measured data on the microcantilever-based mercury detector. They also present design data and measurements of the RF telemetry chip.

  6. System-Level Modelling and Simulation of MEMS-Based Sensors

    DEFF Research Database (Denmark)

    Virk, Kashif M.; Madsen, Jan; Shafique, Mohammad

    2005-01-01

    The growing complexity of MEMS devices and their increased used in embedded systems (e.g., wireless integrated sensor networks) demands a disciplined aproach for MEMS design as well as the development of techniques for system-level modeling of these devices so that a seamless integration...... with the existing embedded system design methodologies is possible. In this paper, we present a MEMS design methodology that uses VHDL-AMS based system-level model of a MEMS device as a starting point and combines the top-down and bottom-up design approaches for design, verification, and optimization...

  7. Design and characterization of in-plane MEMS yaw rate sensor

    Indian Academy of Sciences (India)

    In this paper, we present the design and characterization of a vibratory yaw rate MEMS sensor that uses in-plane motion for both actuation and sensing. The design criterion for the rate sensor is based on a high sensitivity and low bandwidth. The required sensitivity of the yaw rate sensor is attained by using the inplane ...

  8. Integration of nanostructured materials with MEMS microhotplate platforms to enhance chemical sensor performance

    International Nuclear Information System (INIS)

    Benkstein, Kurt D.; Martinez, Carlos J.; Li, Guofeng; Meier, Douglas C.; Montgomery, Christopher B.; Semancik, Steve

    2006-01-01

    The development of miniaturized chemical sensors is an increasingly active area of research. Such devices, particularly when they feature low mass and low power budgets, can impact a broad range of applications including industrial process monitoring, building security and extraterrestrial exploration. Nanostructured materials, because of their high surface area, can provide critical enhancements in the performance of chemical microsensors. We have worked to integrate nanomaterial films with MEMS (microelectromechanical systems) microhotplate platforms developed at the National Institute of Standards and Technology in order to gain the benefits of both the materials and the platforms in high-performance chemical sensor arrays. Here, we describe our success in overcoming the challenges of integration and the benefits that we have achieved with regard to the critical sensor performance characteristics of sensor response, speed, stability and selectivity. Nanostructured metal oxide sensing films were locally deposited onto microhotplates via chemical vapor deposition and microcapillary pipetting, and conductive polymer nanoparticle films were deposited via electrophoretic patterning. All films were characterized by scanning electron microscopy and evaluated as conductometric gas sensors

  9. Thermosensitive gas flow sensor

    International Nuclear Information System (INIS)

    Berlicki, T.; Osadnik, S.; Prociow, E.

    1997-01-01

    Results of investigations on thermal gas flow sensor have been presented. The sensor consists of three thin film resistors Si+Ta. The circuit was designed in the form of two bridges; one of them serves for measurement of the heater temperature, the second one for the measurement of temperature difference of peripheral resistors. The measurement of output voltage versus the rate of nitrogen flow at various power levels dissipated at the heater and various temperatures have been made. The measurements were carried out in three versions; (a) at constant temperature of the heater, (b) at constant power dissipated in the heater, controlled by the power of the heater, (c) at constant temperature of the heater controlled by the power dissipated in the peripheral resistors of the sensor. Due to measurement range it is advantageous to stabilize the temperature of the heater, especially by means of the power supplied to the peripheral resistors. In this case the wider measurement range can be obtained. (author)

  10. CMOS based capacitance to digital converter circuit for MEMS sensor

    Science.gov (United States)

    Rotake, D. R.; Darji, A. D.

    2018-02-01

    Most of the MEMS cantilever based system required costly instruments for characterization, processing and also has large experimental setups which led to non-portable device. So there is a need of low cost, highly sensitive, high speed and portable digital system. The proposed Capacitance to Digital Converter (CDC) interfacing circuit converts capacitance to digital domain which can be easily processed. Recent demand microcantilever deflection is part per trillion ranges which change the capacitance in 1-10 femto farad (fF) range. The entire CDC circuit is designed using CMOS 250nm technology. Design of CDC circuit consists of a D-latch and two oscillators, namely Sensor controlled oscillator (SCO) and digitally controlled oscillator (DCO). The D-latch is designed using transmission gate based MUX for power optimization. A CDC design of 7-stage, 9-stage and 11-stage tested for 1-18 fF and simulated using mentor graphics Eldo tool with parasitic. Since the proposed design does not use resistance component, the total power dissipation is reduced to 2.3621 mW for CDC designed using 9-stage SCO and DCO.

  11. A Study on the Performance of Low Cost MEMS Sensors in Strong Motion Studies

    Science.gov (United States)

    Tanırcan, Gulum; Alçık, Hakan; Kaya, Yavuz; Beyen, Kemal

    2017-04-01

    Recent advances in sensors have helped the growth of local networks. In recent years, many Micro Electro Mechanical System (MEMS)-based accelerometers have been successfully used in seismology and earthquake engineering projects. This is basically due to the increased precision obtained in these downsized instruments. Moreover, they are cheaper alternatives to force-balance type accelerometers. In Turkey, though MEMS-based accelerometers have been used in various individual applications such as magnitude and location determination of earthquakes, structural health monitoring, earthquake early warning systems, MEMS-based strong motion networks are not currently available in other populated areas of the country. Motivation of this study comes from the fact that, if MEMS sensors are qualified to record strong motion parameters of large earthquakes, a dense network can be formed in an affordable price at highly populated areas. The goals of this study are 1) to test the performance of MEMS sensors, which are available in the inventory of the Institute through shake table tests, and 2) to setup a small scale network for observing online data transfer speed to a trusted in-house routine. In order to evaluate the suitability of sensors in strong motion related studies, MEMS sensors and a reference sensor are tested under excitations of sweeping waves as well as scaled earthquake recordings. Amplitude response and correlation coefficients versus frequencies are compared. As for earthquake recordings, comparisons are carried out in terms of strong motion(SM) parameters (PGA, PGV, AI, CAV) and elastic response of structures (Sa). Furthermore, this paper also focuses on sensitivity and selectivity for sensor performances in time-frequency domain to compare different sensing characteristics and analyzes the basic strong motion parameters that influence the design majors. Results show that the cheapest MEMS sensors under investigation are able to record the mid

  12. Micro Coriolis Gas Density Sensor

    NARCIS (Netherlands)

    Sparreboom, Wouter; Ratering, Gijs; Kruijswijk, Wim; van der Wouden, E.J.; Groenesteijn, Jarno; Lötters, Joost Conrad

    2017-01-01

    In this paper we report on gas density measurements using a micro Coriolis sensor. The technology to fabricate the sensor is based on surface channel technology. The measurement tube is freely suspended and has a wall thickness of only 1 micron. This renders the sensor extremely sensitive to changes

  13. Simple fall criteria for MEMS sensors: Data analysis and sensor concept

    KAUST Repository

    Ibrahim, Alwathiqbellah

    2014-07-08

    This paper presents a new and simple fall detection concept based on detailed experimental data of human falling and the activities of daily living (ADLs). Establishing appropriate fall algorithms compatible with MEMS sensors requires detailed data on falls and ADLs that indicate clearly the variations of the kinematics at the possible sensor node location on the human body, such as hip, head, and chest. Currently, there is a lack of data on the exact direction and magnitude of each acceleration component associated with these node locations. This is crucial for MEMS structures, which have inertia elements very close to the substrate and are capacitively biased, and hence, are very sensitive to the direction of motion whether it is toward or away from the substrate. This work presents detailed data of the acceleration components on various locations on the human body during various kinds of falls and ADLs. A two-degree-of-freedom model is used to help interpret the experimental data. An algorithm for fall detection based on MEMS switches is then established. A new sensing concept based on the algorithm is proposed. The concept is based on employing several inertia sensors, which are triggered simultaneously, as electrical switches connected in series, upon receiving a true fall signal. In the case of everyday life activities, some or no switches will be triggered resulting in an open circuit configuration, thereby preventing false positive. Lumped-parameter model is presented for the device and preliminary simulation results are presented illustrating the new device concept. © 2014 by the authors; licensee MDPI, Basel, Switzerland.

  14. MEMS capacitive pressure sensor monolithically integrated with CMOS readout circuit by using post CMOS processes

    Science.gov (United States)

    Jang, Munseon; Yun, Kwang-Seok

    2017-12-01

    In this paper, we presents a MEMS pressure sensor integrated with a readout circuit on a chip for an on-chip signal processing. The capacitive pressure sensor is formed on a CMOS chip by using a post-CMOS MEMS processes. The proposed device consists of a sensing capacitor that is square in shape, a reference capacitor and a readout circuitry based on a switched-capacitor scheme to detect capacitance change at various environmental pressures. The readout circuit was implemented by using a commercial 0.35 μm CMOS process with 2 polysilicon and 4 metal layers. Then, the pressure sensor was formed by wet etching of metal 2 layer through via hole structures. Experimental results show that the MEMS pressure sensor has a sensitivity of 11 mV/100 kPa at the pressure range of 100-400 kPa.

  15. Adaptive UAV Attitude Estimation Employing Unscented Kalman Filter, FOAM and Low-Cost MEMS Sensors

    NARCIS (Netherlands)

    Garcia de Marina Peinado, Hector; Espinosa, Felipe; Santos, Carlos

    Navigation employing low cost MicroElectroMechanical Systems (MEMS) sensors in Unmanned Aerial Vehicles (UAVs) is an uprising challenge. One important part of this navigation is the right estimation of the attitude angles. Most of the existent algorithms handle the sensor readings in a fixed way,

  16. Micro-electro-mechanical system (MEMS)-based fiber optic sensor and sensor network for improving weapon stabilization and fire control

    Science.gov (United States)

    Zhang, Sean Z.; Xu, Guoda; Qiu, Wei; Lin, Freddie S.; Testa, Robert C.; Mattice, Michael S.

    2000-08-01

    A MicroElectroMechanical Systems (MEMS)-based fiber optic sensor and sensor network for improving weapon stabilization and fire control have been developed. Fabrication involves overwriting two fiber Bragg gratings (FBGs) onto a polarization-preserving optical fiber core. A MEMS diaphragm is fabricated and integrated with the overlaid FBGs to enhance the performance and reliability of the sensor. A simulation model for the MEMS fiber optic sensor and sensor network has been derived, and simulation results concerning load, angle, strain, and temperature have been obtained. The fabricated MEMS diaphragm and the overlaid FBGs have been packaged together on the basis of simulation results and mounted on a specially designed cantilever system. The combined multifunctional MEMS fiber optic sensor and sensor network is cost-effective, fast, rugged enough to operate in harsh environmental conditions, compact, and highly sensitive.

  17. New Research on MEMS Acoustic Vector Sensors Used in Pipeline Ground Markers

    Directory of Open Access Journals (Sweden)

    Xiaopeng Song

    2014-12-01

    Full Text Available According to the demands of current pipeline detection systems, the above-ground marker (AGM system based on sound detection principle has been a major development trend in pipeline technology. A novel MEMS acoustic vector sensor for AGM systems which has advantages of high sensitivity, high signal-to-noise ratio (SNR, and good low frequency performance has been put forward. Firstly, it is presented that the frequency of the detected sound signal is concentrated in a lower frequency range, and the sound attenuation is relatively low in soil. Secondly, the MEMS acoustic vector sensor structure and basic principles are introduced. Finally, experimental tests are conducted and the results show that in the range of 0°~90°, when r = 5 m, the proposed MEMS acoustic vector sensor can effectively detect sound signals in soil. The measurement errors of all angles are less than 5°.

  18. MEMS Microphone Array Sensor for Air-Coupled Impact-Echo.

    Science.gov (United States)

    Groschup, Robin; Grosse, Christian U

    2015-06-25

    Impact-Echo (IE) is a nondestructive testing technique for plate like concrete structures. We propose a new sensor concept for air-coupled IE measurements. By using an array of MEMS (micro-electro-mechanical system) microphones, instead of a single receiver, several operational advantages compared to conventional sensing strategies in IE are achieved. The MEMS microphone array sensor is cost effective, less sensitive to undesired effects like acoustic noise and has an optimized sensitivity for signals that need to be extracted for IE data interpretation. The proposed sensing strategy is justified with findings from numerical simulations, showing that the IE resonance in plate like structures causes coherent surface displacements on the specimen under test in an area around the impact location. Therefore, by placing several MEMS microphones on a sensor array board, the IE resonance is easier to be identified in the recorded spectra than with single point microphones or contact type transducers. A comparative measurement between the array sensor, a conventional accelerometer and a measurement microphone clearly shows the suitability of MEMS type microphones and the advantages of using these microphones in an array arrangement for IE. The MEMS microphone array will make air-coupled IE measurements faster and more reliable.

  19. A grasping forceps with a triaxial MEMS tactile sensor for quantification of stresses on organs.

    Science.gov (United States)

    Kuwana, K; Nakai, A; Masamune, K; Dohi, T

    2013-01-01

    This paper reports on a grasping forceps with a triaxial Micro Electro Mechanical Systems (MEMS) tactile sensor on a tip. The laparoscopic surgery is minimally invasive because the incisions are smaller than the open surgery. This results in fast recovery. However, it is a problem in the laparoscopic surgery to damage an organ by localized stress generated by grasping with a thin forceps. To avoid excessive stress applying to the organ, real time evaluation of the stress is important. However, there is no acceptable tool to measure the stress. We propose a grasping forceps with a triaxial MEMS tactile sensor on a tip for a measurement tool. We attached a triaxial MEMS tactile sensor which we have developed on a tip of a grasping forceps. The MEMS sensor can measure not only the pressure but also two directional shear stresses applied to the sensor surface. The sensor size is 7 mm × 7 mm × 2 mm. It is enough small to attach the sensor to the tip of a forceps 12 mm in diameter. In this paper, the characteristics of the forceps with the MEMS sensor during grasping, pushing and pulling actions were evaluated. In these experiments, output of each sensor for pressure and shear stress was proportional to the applied stresses, respectively. Moreover, as an in vivo experiment, we measured the shear stress applied to a pig liver block when it is lifted after being grasped with the forceps. We obtained that the shear stress applied to the liver block increased with the increase of the weight of the liver block.

  20. Monitoring System for Slope Stability under Rainfall by using MEMS Acceleration Sensor IC tags

    International Nuclear Information System (INIS)

    Murakami, S; Dairaku, A; Komine, H; Saito, O; Sakai, N; Isizawa, T; Maruyama, I

    2013-01-01

    Real-time warning system for slope failure under rainfall is available to disaster prevention and mitigation. Monitoring of multi-point and wireless measurements is effective because it is difficult to conclude the most dangerous part in a slope. The purpose of this study is to propose a method of monitoring system with multi-point and wireless measurements for a slope stability using MEMS acceleration sensor IC tags. MEMS acceleration sensor IC tag is an acceleration sensor microminiaturized by a technology of Micro Electro Mechanical Systems on board IC tag. Especially, low cost of the sensor will yield to the realization of the system. In order to investigate the applicability of the proposed system, a large-scale model test of artificial slope subjected to rainfall has been performed. MEMS acceleration sensor IC tags has been located on the slope and ground acceleration caused by forced vibration has been measured until the model slope collapses. The experimental results show that the MEMS acceleration sensor IC tag is comfortably available under rainfall, the characteristics of ground accelerations varies with changing the condition of the slope subjected to rainfall, and the proposed method can be applied to a real-time monitoring system for slope failure under rainfall.

  1. Miniaturized MEMS-Based Gas Chromatograph for High Inertial Loads Associated with Planetary Missions, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Thorleaf Research, Inc. proposes to develop a rugged, miniaturized, low power MEMS-based gas chromatograph (GC) capable of handling the high inertial loads...

  2. Multi-scale Analysis of MEMS Sensors Subject to Drop Impacts

    Directory of Open Access Journals (Sweden)

    Sarah Zerbini

    2007-09-01

    Full Text Available The effect of accidental drops on MEMS sensors are examined within the frame-work of a multi-scale finite element approach. With specific reference to a polysilicon MEMSaccelerometer supported by a naked die, the analysis is decoupled into macro-scale (at dielength-scale and meso-scale (at MEMS length-scale simulations, accounting for the verysmall inertial contribution of the sensor to the overall dynamics of the device. Macro-scaleanalyses are adopted to get insights into the link between shock waves caused by the impactagainst a target surface and propagating inside the die, and the displacement/acceleration his-tories at the MEMS anchor points. Meso-scale analyses are adopted to detect the most stresseddetails of the sensor and to assess whether the impact can lead to possible localized failures.Numerical results show that the acceleration at sensor anchors cannot be considered an ob-jective indicator for drop severity. Instead, accurate analyses at sensor level are necessary toestablish how MEMS can fail because of drops.

  3. Gas-leak localization using distributed ultrasonic sensors

    Science.gov (United States)

    Huseynov, Javid; Baliga, Shankar; Dillencourt, Michael; Bic, Lubomir; Bagherzadeh, Nader

    2009-03-01

    We propose an ultrasonic gas leak localization system based on a distributed network of sensors. The system deploys highly sensitive miniature Micro-Electro-Mechanical Systems (MEMS) microphones and uses a suite of energy-decay (ED) and time-delay of arrival (TDOA) algorithms for localizing a source of a gas leak. Statistical tools such as the maximum likelihood (ML) and the least squares (LS) estimators are used for approximating the source location when closed-form solutions fail in the presence of ambient background nuisance and inherent electronic noise. The proposed localization algorithms were implemented and tested using a Java-based simulation platform connected to four or more distributed MEMS microphones observing a broadband nitrogen leak from an orifice. The performance of centralized and decentralized algorithms under ED and TDOA schemes is analyzed and compared in terms of communication overhead and accuracy in presence of additive white Gaussian noise (AWGN).

  4. An alternative sensor fusion method for object orientation using low-cost MEMS inertial sensors

    Science.gov (United States)

    Bouffard, Joshua L.

    This thesis develops an alternative sensor fusion approach for object orientation using low-cost MEMS inertial sensors. The alternative approach focuses on the unique challenges of small UAVs. Such challenges include the vibrational induced noise onto the accelerometer and bias offset errors of the rate gyroscope. To overcome these challenges, a sensor fusion algorithm combines the measured data from the accelerometer and rate gyroscope to achieve a single output free from vibrational noise and bias offset errors. One of the most prevalent sensor fusion algorithms used for orientation estimation is the Extended Kalman filter (EKF). The EKF filter performs the fusion process by first creating the process model using the nonlinear equations of motion and then establishing a measurement model. With the process and measurement models established, the filter operates by propagating the mean and covariance of the states through time. The success of EKF relies on the ability to establish a representative process and measurement model of the system. In most applications, the EKF measurement model utilizes the accelerometer and GPS-derived accelerations to determine an estimate of the orientation. However, if the GPS-derived accelerations are not available then the measurement model becomes less reliable when subjected to harsh vibrational environments. This situation led to the alternative approach, which focuses on the correlation between the rate gyroscope and accelerometer-derived angle. The correlation between the two sensors then determines how much the algorithm will use one sensor over the other. The result is a measurement that does not suffer from the vibrational noise or from bias offset errors.

  5. Recent Advances of MEMS Resonators for Lorentz Force Based Magnetic Field Sensors: Design, Applications and Challenges

    Directory of Open Access Journals (Sweden)

    Agustín Leobardo Herrera-May

    2016-08-01

    Full Text Available Microelectromechanical systems (MEMS resonators have allowed the development of magnetic field sensors with potential applications such as biomedicine, automotive industry, navigation systems, space satellites, telecommunications and non-destructive testing. We present a review of recent magnetic field sensors based on MEMS resonators, which operate with Lorentz force. These sensors have a compact structure, wide measurement range, low energy consumption, high sensitivity and suitable performance. The design methodology, simulation tools, damping sources, sensing techniques and future applications of magnetic field sensors are discussed. The design process is fundamental in achieving correct selection of the operation principle, sensing technique, materials, fabrication process and readout systems of the sensors. In addition, the description of the main sensing systems and challenges of the MEMS sensors are discussed. To develop the best devices, researches of their mechanical reliability, vacuum packaging, design optimization and temperature compensation circuits are needed. Future applications will require multifunctional sensors for monitoring several physical parameters (e.g., magnetic field, acceleration, angular ratio, humidity, temperature and gases.

  6. Recent Advances of MEMS Resonators for Lorentz Force Based Magnetic Field Sensors: Design, Applications and Challenges.

    Science.gov (United States)

    Herrera-May, Agustín Leobardo; Soler-Balcazar, Juan Carlos; Vázquez-Leal, Héctor; Martínez-Castillo, Jaime; Vigueras-Zuñiga, Marco Osvaldo; Aguilera-Cortés, Luz Antonio

    2016-08-24

    Microelectromechanical systems (MEMS) resonators have allowed the development of magnetic field sensors with potential applications such as biomedicine, automotive industry, navigation systems, space satellites, telecommunications and non-destructive testing. We present a review of recent magnetic field sensors based on MEMS resonators, which operate with Lorentz force. These sensors have a compact structure, wide measurement range, low energy consumption, high sensitivity and suitable performance. The design methodology, simulation tools, damping sources, sensing techniques and future applications of magnetic field sensors are discussed. The design process is fundamental in achieving correct selection of the operation principle, sensing technique, materials, fabrication process and readout systems of the sensors. In addition, the description of the main sensing systems and challenges of the MEMS sensors are discussed. To develop the best devices, researches of their mechanical reliability, vacuum packaging, design optimization and temperature compensation circuits are needed. Future applications will require multifunctional sensors for monitoring several physical parameters (e.g., magnetic field, acceleration, angular ratio, humidity, temperature and gases).

  7. Thermoacoustic waves in pulsed Pirani sensor MEMS. Numerical Investigation

    Directory of Open Access Journals (Sweden)

    Gospodinov Peter

    2018-01-01

    Full Text Available The transient heat transfer process is studied in rarefied gas confined between two stationary concentric cylinders. The inner cylinder (filament is subjected to a periodically heating-cooling cycle. The energy transfer is modeled with continuous model based on Navier-Sockes Fourier equations of motion and energy transfer and with a statistical DSMC model. Numerical results for the temperature, thermodynamic pressure and pressure difference between thermodynamic pressure and radial stress tensor component are obtained for different circular frequencies of heating cooling cycle of filament and for different filament radii. The pressure variation at the end of any local heating stage of heating-cooling cycle is close to the value of equilibrium thermodynamic pressure. The results are applicable in designing the pulsed Pirani sensors.

  8. Design and modeling of an all-optical frequency modulated MEMS strain sensor using nanoscale Bragg gratings

    DEFF Research Database (Denmark)

    Reck, Kasper; Almind, Ninia Sejersen; Mar, Mikkel Dysseholm

    2009-01-01

    We present modeling and design of an all-optical MEMS Bragg grating (half-pitch of 125 nm) strain sensor for single-fiber distributed sensing. Low optical loss and the use of frequency modulation rather than amplitude modulation, makes this sensor better suited for distributed systems than...... mechanical amplification can be obtained if using an angled double beam micrometer scale MEMS structure, compared to conventional fiber Bragg grating sensors. An optimized design and fabrication process is presented....

  9. The Sandia MEMS Passive Shock Sensor : FY08 testing for functionality, model validation, and technology readiness.

    Energy Technology Data Exchange (ETDEWEB)

    Walraven, Jeremy Allen; Blecke, Jill; Baker, Michael Sean; Clemens, Rebecca C.; Mitchell, John Anthony; Brake, Matthew Robert; Epp, David S.; Wittwer, Jonathan W.

    2008-10-01

    This report summarizes the functional, model validation, and technology readiness testing of the Sandia MEMS Passive Shock Sensor in FY08. Functional testing of a large number of revision 4 parts showed robust and consistent performance. Model validation testing helped tune the models to match data well and identified several areas for future investigation related to high frequency sensitivity and thermal effects. Finally, technology readiness testing demonstrated the integrated elements of the sensor under realistic environments.

  10. A Simple Model for Complex Fabrication of MEMS based Pressure Sensor: A Challenging Approach

    Directory of Open Access Journals (Sweden)

    Himani SHARMA

    2010-08-01

    Full Text Available In this paper we have presented the simple model for complex fabrication of MEMS based absolute micro pressure sensor. This kind of modeling is extremely useful for determining its complexity in fabrication steps and provides complete information about process sequence to be followed during manufacturing. Therefore, the need for test iteration decreases and cost, time can be reduced significantly. By using DevEdit tool (part of SILVACO tool, a behavioral model of pressure sensor have been presented and implemented.

  11. System-in Package of Integrated Humidity Sensor Using CMOS-MEMS Technology.

    Science.gov (United States)

    Lee, Sung Pil

    2015-10-01

    Temperature/humidity microchips with micropump were fabricated using a CMOS-MEMS process and combined with ZigBee modules to implement a sensor system in package (SIP) for a ubiquitous sensor network (USN) and/or a wireless communication system. The current of a diode temperature sensor to temperature and a normalized current of FET humidity sensor to relative humidity showed linear characteristics, respectively, and the use of the micropump has enabled a faster response. A wireless reception module using the same protocol as that in transmission systems processed the received data within 10 m and showed temperature and humidity values in the display.

  12. Pressure sensor based on MEMS nano-cantilever beam structure as a heterodielectric gate electrode of dopingless TFET

    Science.gov (United States)

    Kumar, Gagan; Raman, Ashish

    2016-12-01

    Micro-electromechanical systems (MEMS) technology has enticed numerous scientists since recent decades particularly in the field of miniaturized-sensors and actuators. Pressure sensor is pivotal component in both of the forerunning fields. The pursuance of a pressure sensor is exigently relying upon its different physical properties i.e. Piezo-resistive, Piezoelectric, Capacitive, Magnetic and Electrostatic. This article presents an outline and scrutiny of the Doping-less Cantilever Based Pressure Sensor using tunnel field effect transistor technology. The propounded pressure sensor based on the principle of capacitive gate coupling, due to which the tunneling current is modified. Additionally, to enhance the affectability of pressure sensor, the work function of metal gate electrode is amended using gas molecule diffusion. Simulation uncovers a phenomenal relationship amongst hypothetical and practical accepts of configuration. The pressure sensor is composed at Silvaco Atlas tool utilizing 40 nm technologies. The performance results exhibit that the proposed model consumes ≤1 mW power and 250 μA tunneling current per nm bending of cantilever beam structure. The inclusive length of the proposed device is 100 nm.

  13. A Nonlinear Attitude Estimator for Attitude and Heading Reference Systems Based on MEMS Sensors

    DEFF Research Database (Denmark)

    Wang, Yunlong; Soltani, Mohsen; Hussain, Dil muhammed Akbar

    2016-01-01

    In this paper, a nonlinear attitude estimator is designed for an Attitude Heading and Reference System (AHRS) based on Micro Electro-Mechanical Systems (MEMS) sensors. The design process of the attitude estimator is stated with detail, and the equilibrium point of the estimator error model...... the problems in previous research works. Moreover, the estimation of MEMS gyroscope bias is also inclueded in this estimator. The designed nonlinear attitude estimator is firstly tested in simulation environment and then implemented in an AHRS hardware for further experiments. Finally, the attitude estimation...

  14. Design and measurement of a piezoresistive ultrasonic sensor based on MEMS

    Science.gov (United States)

    Jiaqi, Yu; Changde, He; Kejing, Yuan; Deqin, Lian; Chenyang, Xue; Wendong, Zhang

    2013-07-01

    A kind of piezoresistive ultrasonic sensor based on MEMS is proposed, which is composed of a membrane and two side beams. A simplified mathematical model has been established to analyze the mechanical properties of the sensor. On the basis of the theoretical analysis, the structural size and layout location of the piezoresistors are determined by simulation analysis. The boron-implanted piezoresistors located on membrane and side beams form a Wheatstone bridge to detect acoustic signal. The membrane-beam microstructure is fabricated integrally by MEMS manufacturing technology. Finally, this paper presents the experimental characterization of the ultrasonic sensor, validating the theoretical model used and the simulated model. The sensitivity reaches -116.2 dB (0 dB reference = 1 V/μbar, 31 kHz), resonant frequency is 39.6 kHz, direction angle is 55°.

  15. Enhancement of Frequency Stability Using Synchronization of a Cantilever Array for MEMS-Based Sensors

    Directory of Open Access Journals (Sweden)

    Francesc Torres

    2016-10-01

    Full Text Available Micro and nano electromechanical resonators have been widely used as single or multiple-mass detection sensors. Smaller devices with higher resonance frequencies and lower masses offer higher mass responsivities but suffer from lower frequency stability. Synchronization phenomena in multiple MEMS resonators have become an important issue because they allow frequency stability improvement, thereby preserving mass responsivity. The authors present an array of five cantilevers (CMOS-MEMS system that are forced to vibrate synchronously to enhance their frequency stability. The frequency stability has been determined in closed-loop configuration for long periods of time by calculating the Allan deviation. An Allan deviation of 0.013 ppm (@ 1 s averaging time for a 1 MHz cantilever array MEMS system was obtained at the synchronized mode, which represents a 23-fold improvement in comparison with the non-synchronized operation mode (0.3 ppm.

  16. Design and fabrication of a flexible MEMS-based electromechanical sensor array for breast cancer diagnosis.

    Science.gov (United States)

    Pandya, Hardik J; Park, Kihan; Desai, Jaydev P

    2015-06-23

    The use of flexible micro-electro-mechanical systems (MEMS) based device provides a unique opportunity in bio-medical robotics such as characterization of normal and malignant tissues. This paper reports on design and development of a flexible MEMS-based sensor array integrating mechanical and electrical sensors on the same platform to enable the study of the change in electro-mechanical properties of the benign and cancerous breast tissues. In this work, we present the analysis for the electrical characterization of the tissue specimens and also demonstrate the feasibility of using the sensor for mechanical characterization of the tissue specimens. Eight strain gauges acting as mechanical sensors were fabricated using poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) conducting polymer on poly(dimethylsiloxane) (PDMS) as the substrate material. Eight electrical sensors were fabricated using SU-8 pillars on gold (Au) pads which were patterned on the strain gauges separated by a thin insulator (SiO 2 1.0μm). These pillars were coated with gold to make it conducting. The electromechanical sensors are integrated on the same substrate. The sensor array covers 180μm × 180μm area and the size of the complete device is 20mm in diameter. The diameter of each breast tissue core used in the present study was 1mm and the thickness was 8μm. The region of interest was 200μm × 200μm. Microindentation technique was used to characterize the mechanical properties of the breast tissues. The sensor is integrated with conducting SU-8 pillars to study the electrical property of the tissue. Through electro-mechanical characterization studies using this MEMS-based sensor, we were able to measure the accuracy of the fabricated device and ascertain the difference between benign and cancer breast tissue specimens.

  17. Radio frequency power sensor based on MEMS technology

    NARCIS (Netherlands)

    Fernandez, L.J.; Visser, Eelke; Sesé, J.; Wiegerink, Remco J.; Jansen, Henricus V.; Flokstra, Jan; Flokstra, Jakob; Elwenspoek, Michael Curt

    2003-01-01

    We present the first measurement results of a power sensor for radio frequency (rf) signals (50 kHz - 40 GHz) with almost no dissipation during the measurement. This sensor is, therefore, a 'through' power sensor, that means that the rf signal is available during the measurement of its power. The

  18. A MEMS SOI-based piezoresistive fluid flow sensor

    Science.gov (United States)

    Tian, B.; Li, H. F.; Yang, H.; Song, D. L.; Bai, X. W.; Zhao, Y. L.

    2018-02-01

    In this paper, a SOI (silicon-on-insulator)-based piezoresistive fluid flow sensor is presented; the presented flow sensor mainly consists of a nylon sensing head, stainless steel cantilever beam, SOI sensor chip, printed circuit board, half-cylinder gasket, and stainless steel shell. The working principle of the sensor and some detailed contrastive analysis about the sensor structure were introduced since the nylon sensing head and stainless steel cantilever beam have distinct influence on the sensor performance; the structure of nylon sensing head and stainless steel cantilever beam is also discussed. The SOI sensor chip was fabricated using micro-electromechanical systems technologies, such as reactive ion etching and low pressure chemical vapor deposition. The designed fluid sensor was packaged and tested; a calibration installation system was purposely designed for the sensor experiment. The testing results indicated that the output voltage of the sensor is proportional to the square of the fluid flow velocity, which is coincident with the theoretical derivation. The tested sensitivity of the sensor is 3.91 × 10-4 V ms2/kg.

  19. A MEMS SOI-based piezoresistive fluid flow sensor.

    Science.gov (United States)

    Tian, B; Li, H F; Yang, H; Song, D L; Bai, X W; Zhao, Y L

    2018-02-01

    In this paper, a SOI (silicon-on-insulator)-based piezoresistive fluid flow sensor is presented; the presented flow sensor mainly consists of a nylon sensing head, stainless steel cantilever beam, SOI sensor chip, printed circuit board, half-cylinder gasket, and stainless steel shell. The working principle of the sensor and some detailed contrastive analysis about the sensor structure were introduced since the nylon sensing head and stainless steel cantilever beam have distinct influence on the sensor performance; the structure of nylon sensing head and stainless steel cantilever beam is also discussed. The SOI sensor chip was fabricated using micro-electromechanical systems technologies, such as reactive ion etching and low pressure chemical vapor deposition. The designed fluid sensor was packaged and tested; a calibration installation system was purposely designed for the sensor experiment. The testing results indicated that the output voltage of the sensor is proportional to the square of the fluid flow velocity, which is coincident with the theoretical derivation. The tested sensitivity of the sensor is 3.91 × 10 -4 V ms 2 /kg.

  20. Cost-Efficient Wafer-Level Capping for MEMS and Imaging Sensors by Adhesive Wafer Bonding

    Directory of Open Access Journals (Sweden)

    Simon J. Bleiker

    2016-10-01

    Full Text Available Device encapsulation and packaging often constitutes a substantial part of the fabrication cost of micro electro-mechanical systems (MEMS transducers and imaging sensor devices. In this paper, we propose a simple and cost-effective wafer-level capping method that utilizes a limited number of highly standardized process steps as well as low-cost materials. The proposed capping process is based on low-temperature adhesive wafer bonding, which ensures full complementary metal-oxide-semiconductor (CMOS compatibility. All necessary fabrication steps for the wafer bonding, such as cavity formation and deposition of the adhesive, are performed on the capping substrate. The polymer adhesive is deposited by spray-coating on the capping wafer containing the cavities. Thus, no lithographic patterning of the polymer adhesive is needed, and material waste is minimized. Furthermore, this process does not require any additional fabrication steps on the device wafer, which lowers the process complexity and fabrication costs. We demonstrate the proposed capping method by packaging two different MEMS devices. The two MEMS devices include a vibration sensor and an acceleration switch, which employ two different electrical interconnection schemes. The experimental results show wafer-level capping with excellent bond quality due to the re-flow behavior of the polymer adhesive. No impediment to the functionality of the MEMS devices was observed, which indicates that the encapsulation does not introduce significant tensile nor compressive stresses. Thus, we present a highly versatile, robust, and cost-efficient capping method for components such as MEMS and imaging sensors.

  1. MEMS and FOG Technologies for Tactical and Navigation Grade Inertial Sensors-Recent Improvements and Comparison.

    Science.gov (United States)

    Deppe, Olaf; Dorner, Georg; König, Stefan; Martin, Tim; Voigt, Sven; Zimmermann, Steffen

    2017-03-11

    In the following paper, we present an industry perspective of inertial sensors for navigation purposes driven by applications and customer needs. Microelectromechanical system (MEMS) inertial sensors have revolutionized consumer, automotive, and industrial applications and they have started to fulfill the high end tactical grade performance requirements of hybrid navigation systems on a series production scale. The Fiber Optic Gyroscope (FOG) technology, on the other hand, is further pushed into the near navigation grade performance region and beyond. Each technology has its special pros and cons making it more or less suitable for specific applications. In our overview paper, we present latest improvements at NG LITEF in tactical and navigation grade MEMS accelerometers, MEMS gyroscopes, and Fiber Optic Gyroscopes, based on our long-term experience in the field. We demonstrate how accelerometer performance has improved by switching from wet etching to deep reactive ion etching (DRIE) technology. For MEMS gyroscopes, we show that better than 1°/h series production devices are within reach, and for FOGs we present how limitations in noise performance were overcome by signal processing. The paper also intends a comparison of the different technologies, emphasizing suitability for different navigation applications, thus providing guidance to system engineers.

  2. Hybrid Integration of Magnetoresistive Sensors with MEMS as a Strategy to Detect Ultra-Low Magnetic Fields

    Directory of Open Access Journals (Sweden)

    João Valadeiro

    2016-05-01

    Full Text Available In this paper, we describe how magnetoresistive sensors can be integrated with microelectromechanical systems (MEMS devices enabling the mechanical modulation of DC or low frequency external magnetic fields to high frequencies using MEMS structures incorporating magnetic flux guides. In such a hybrid architecture, lower detectivities are expected when compared with those obtained for individual sensors. This particularity results from the change of sensor’s operating point to frequencies above the 1/f noise knee.

  3. On the Modeling of an Open Channel MEMS Based Capacitive Flow Sensor

    Directory of Open Access Journals (Sweden)

    Vafaghi Maryam

    2008-11-01

    Full Text Available In this paper an open channel MEMS capacitive flow sensor has been designed based on a microplate deflection measuring. Proposed flow sensor consists with two separate units, one for sensing the static fluid pressure and the other for sensing the fluid static and dynamic pressure. The governing equation whose solution holds the answer to all our questions about the sensor’s characteristics is a nonlinear elasto-electrostatic equation. Sensor’s static response and mechanical behavior of the sensing elements in a channel have been simulated numerically by using of Step by Step Linearization Method. The sensor stability has been examined and the stable region of the sensor has been studied. The effect of fluid velocity and static pressure on stability limit of the sensor has been investigated and the effect of bias voltage on sensor sensitivity has been studied.

  4. Airborne Multi-Gas Sensor, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Mesa Photonics has developed laser-based gas sensor technology compatible with UAV deployment. Our Airborne MUlti-Gas Sensor (AMUGS) technology is based upon...

  5. Novel Designs for Application Specific MEMS Pressure Sensors

    Directory of Open Access Journals (Sweden)

    Erik V. Thomsen

    2010-10-01

    Full Text Available In the framework of developing innovative microfabricated pressure sensors, we present here three designs based on different readout principles, each one tailored for a specific application. A touch mode capacitive pressure sensor with high sensitivity (14 pF/bar, low temperature dependence and high capacitive output signal (more than 100 pF is depicted. An optical pressure sensor intrinsically immune to electromagnetic interference, with large pressure range (0–350 bar and a sensitivity of 1 pm/bar is presented. Finally, a resonating wireless pressure sensor power source free with a sensitivity of 650 KHz/mmHg is described. These sensors will be related with their applications in  harsh environment, distributed systems and medical environment, respectively. For many aspects, commercially available sensors, which in vast majority are piezoresistive, are not suited for the applications proposed.

  6. Novel Designs for Application Specific MEMS Pressure Sensors

    DEFF Research Database (Denmark)

    Fragiacomo, Giulio; Reck, Kasper; Lorenzen, Lasse Vestergaard

    2010-01-01

    In the framework of developing innovative microfabricated pressure sensors, we present here three designs based on different readout principles, each one tailored for a specific application. A touch mode capacitive pressure sensor with high sensitivity (14 pF/bar), low temperature dependence...... and high capacitive output signal (more than 100 pF) is depicted. An optical pressure sensor intrinsically immune to electromagnetic interference, with large pressure range (0-350 bar) and a sensitivity of 1 pm/bar is presented. Finally, a resonating wireless pressure sensor power source free...... with a sensitivity of 650 KHz/mmHg is described. These sensors will be related with their applications in harsh environment, distributed systems and medical environment, respectively. For many aspects, commercially available sensors, which in vast majority are piezoresistive, are not suited for the applications...

  7. Intelligent gas-mixture flow sensor

    NARCIS (Netherlands)

    Lammerink, Theodorus S.J.; Dijkstra, Fred; Houkes, Z.; van Kuijk, J.C.C.; van Kuijk, Joost

    A simple way to realize a gas-mixture flow sensor is presented. The sensor is capable of measuring two parameters from a gas flow. Both the flow rate and the helium content of a helium-nitrogen gas mixture are measured. The sensor exploits two measurement principles in combination with (local)

  8. Single-mask thermal displacement sensor in MEMS

    NARCIS (Netherlands)

    Krijnen, B.; Hogervorst, R.P.; Engelen, Johannes Bernardus Charles; van Dijk, J.W.; Brouwer, Dannis Michel; Abelmann, Leon

    In this work we describe a one degree- of-freedom microelectromechanical thermal displacement sensor integrated with an actuated stage. The system was fabricated in the device layer of a silicon-on-insulator wafer using a single-mask process. The sensor is based on the temperature dependent

  9. Polyimide/SU-8 catheter-tip MEMS gauge pressure sensor

    OpenAIRE

    Hasenkamp, Willyan; Forchelet, David; Pataky, Kristopher; Villard, Jimmy; Lintel, Harald Van; Bertsch, Arnaud; Wang, Qing; Renaud, Philippe

    2012-01-01

    This paper describes the development of a polyimide/SU-8 catheter-tip MEMS gauge pressure sensor. Finite element analysis was used to investigate critical parameters, impacting on the device design and sensing characteristics. The sensing element of the device was fabricated by polyimide-based micromachining on a flexible membrane, using embedded thin-film metallic wires as piezoresistive elements. A chamber containing this flexible membrane was sealed using an adapted SU-8 bonding technique....

  10. Development of a wireless MEMS multifunction sensor system and field demonstration of embedded sensors for monitoring concrete pavements : tech transfer summary.

    Science.gov (United States)

    2016-08-01

    Micro-electromechanical sensors and systems- (MEMS)-based and : wireless-based smart-sensing technologies have, until now, rarely : been used for monitoring pavement response in the field, and the : requirements for using such smart sensing technolog...

  11. A Capacitance-To-Digital Converter for MEMS Sensors for Smart Applications.

    Science.gov (United States)

    Pérez Sanjurjo, Javier; Prefasi, Enrique; Buffa, Cesare; Gaggl, Richard

    2017-06-07

    The use of MEMS sensors has been increasing in recent years. To cover all the applications, many different readout circuits are needed. To reduce the cost and time to market, a generic capacitance-to-digital converter (CDC) seems to be the logical next step. This work presents a configurable CDC designed for capacitive MEMS sensors. The sensor is built with a bridge of MEMS, where some of them function with pressure. Then, the capacitive to digital conversion is realized using two steps. First, a switched-capacitor (SC) preamplifier is used to make the capacitive to voltage (C-V) conversion. Second, a self-oscillated noise-shaping integrating dual-slope (DS) converter is used to digitize this magnitude. The proposed converter uses time instead of amplitude resolution to generate a multibit digital output stream. In addition it performs noise shaping of the quantization error to reduce measurement time. This article shows the effectiveness of this method by measurements performed on a prototype, designed and fabricated using standard 0.13 µm CMOS technology. Experimental measurements show that the CDC achieves a resolution of 17 bits, with an effective area of 0.317 mm², which means a pressure resolution of 1 Pa, while consuming 146 µA from a 1.5 V power supply.

  12. Spring constant measurement using a MEMS force and displacement sensor utilizing paralleled piezoresistive cantilevers

    Science.gov (United States)

    Kohyama, Sumihiro; Takahashi, Hidetoshi; Yoshida, Satoru; Onoe, Hiroaki; Hirayama-Shoji, Kayoko; Tsukagoshi, Takuya; Takahata, Tomoyuki; Shimoyama, Isao

    2018-04-01

    This paper reports on a method to measure a spring constant on site using a micro electro mechanical systems (MEMS) force and displacement sensor. The proposed sensor consists of a force-sensing cantilever and a displacement-sensing cantilever. Each cantilever is composed of two beams with a piezoresistor on the sidewall for measuring the in-plane lateral directional force and displacement. The force resolution and displacement resolution of the fabricated sensor were less than 0.8 µN and 0.1 µm, respectively. We measured the spring constants of two types of hydrogel microparticles to demonstrate the effectiveness of the proposed sensor, with values of approximately 4.3 N m-1 and 15.1 N m-1 obtained. The results indicated that the proposed sensor is effective for on-site spring constant measurement.

  13. Novel architecture for measurements in resistive MEMS sensors

    Science.gov (United States)

    Nandi, Prajit; Biswas, Riju; Sundar Dhar, Anindya; Das, Soumen

    2014-05-01

    A low voltage, low power, resistive sensor architecture is proposed in this paper. The architecture is novel as it enhances the sensitivity along the main axis as well as reducing the impact of cross axes components. The proposed scheme also allows the simultaneous measurement of sensitivity along six different axes. With less than 15% of the power of its Wheatstone bridge [1] counterpart and with a voltage level as low as 2.25 V, this architecture also enables the realization of the sensor using fewer resistive elements. The modified sensor structure, along with the front-end signal processing circuit, is discussed.

  14. Power for Vehicle Embedded MEMS Sensors, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Embedded wireless sensors of the future will enable flight vehicle systems to be "highly aware" of onboard health and performance parameters, as well as the external...

  15. Power for Vehicle Embedded MEMS Sensors, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Embedded wireless sensors of the future will enable flight vehicle systems to be "highly aware" of onboard health and performance parameters, as well as the external...

  16. Polyimide/SU-8 catheter-tip MEMS gauge pressure sensor.

    Science.gov (United States)

    Hasenkamp, Willyan; Forchelet, David; Pataky, Kristopher; Villard, Jimmy; Van Lintel, Harald; Bertsch, Arnaud; Wang, Qing; Renaud, Philippe

    2012-10-01

    This paper describes the development of a polyimide/SU-8 catheter-tip MEMS gauge pressure sensor. Finite element analysis was used to investigate critical parameters, impacting on the device design and sensing characteristics. The sensing element of the device was fabricated by polyimide-based micromachining on a flexible membrane, using embedded thin-film metallic wires as piezoresistive elements. A chamber containing this flexible membrane was sealed using an adapted SU-8 bonding technique. The device was evaluated experimentally and its overall performance compared with a commercial silicon-based pressure sensor. Furthermore, the device use was demonstrated by measuring blood pressure and heart rate in vivo.

  17. MEMS Accelerometers Sensors: an Application in Virtual Reality

    Directory of Open Access Journals (Sweden)

    Daniel CORRÊA

    2010-09-01

    Full Text Available The measurement of a particular human body member position is extremely important in many applications. The human behavior understanding typically involves the body posture analysis or estimation, as well as the generated corresponding gestures. This behavior characterization allows analyzing, interpreting, and animating human actions and therefore enables us the use of experimental methodologies. Using the virtual reality devices to facilitate people’s lives, they can help to train and improve the actions of an Olympic athlete, for example and imitation of human actions by robotic systems. The systems development to monitor human body members’ movements is a growing interesting area, both in entertainment and in systems to help physically disabled people, as that developing assistive technology. To contribute to this area, this paper presents the experimental development of an instrumented glove prototype of low cost for the recognition of hand inclination movements, using a Micro-Electro-Mechanical Systems (MEMS accelerometer, by virtual reality concepts for demonstration in real time. We present the hardware that was developed, the calibration procedures, the achieved results with their statistical corresponding validation. The results allowed to state that the system is suitable for the inclination measurement in a 2D plan, thus allowing its use in entertainment systems and as an auxiliary device for assistive technology system.

  18. An Integrated Thermal Compensation System for MEMS Inertial Sensors

    Directory of Open Access Journals (Sweden)

    Sheng-Ren Chiu

    2014-03-01

    Full Text Available An active thermal compensation system for a low temperature-bias-drift (TBD MEMS-based gyroscope is proposed in this study. First, a micro-gyroscope is fabricated by a high-aspect-ratio silicon-on-glass (SOG process and vacuum packaged by glass frit bonding. Moreover, a drive/readout ASIC, implemented by the 0.25 µm 1P5M standard CMOS process, is designed and integrated with the gyroscope by directly wire bonding. Then, since the temperature effect is one of the critical issues in the high performance gyroscope applications, the temperature-dependent characteristics of the micro-gyroscope are discussed. Furthermore, to compensate the TBD of the micro-gyroscope, a thermal compensation system is proposed and integrated in the aforementioned ASIC to actively tune the parameters in the digital trimming mechanism, which is designed in the readout ASIC. Finally, some experimental results demonstrate that the TBD of the micro-gyroscope can be compensated effectively by the proposed compensation system.

  19. High-performance piezoresistive MEMS strain sensor with low thermal sensitivity.

    Science.gov (United States)

    Mohammed, Ahmed A S; Moussa, Walied A; Lou, Edmond

    2011-01-01

    This paper presents the experimental evaluation of a new piezoresistive MEMS strain sensor. Geometric characteristics of the sensor silicon carrier have been employed to improve the sensor sensitivity. Surface features or trenches have been introduced in the vicinity of the sensing elements. These features create stress concentration regions (SCRs) and as a result, the strain/stress field was altered. The improved sensing sensitivity compensated for the signal loss. The feasibility of this methodology was proved in a previous work using Finite Element Analysis (FEA). This paper provides the experimental part of the previous study. The experiments covered a temperature range from -50 °C to +50 °C. The MEMS sensors are fabricated using five different doping concentrations. FEA is also utilized to investigate the effect of material properties and layer thickness of the bonding adhesive on the sensor response. The experimental findings are compared to the simulation results to guide selection of bonding adhesive and installation procedure. Finally, FEA was used to analyze the effect of rotational/alignment errors.

  20. Graphene ``microdrums'' on a freestanding perforated thin membrane for high sensitivity MEMS pressure sensors

    Science.gov (United States)

    Wang, Qiugu; Hong, Wei; Dong, Liang

    2016-03-01

    We present a microelectromechanical system (MEMS) graphene-based pressure sensor realized by transferring a large area, few-layered graphene on a suspended silicon nitride thin membrane perforated by a periodic array of micro-through-holes. Each through-hole is covered by a circular drum-like graphene layer, namely a graphene ``microdrum''. The uniqueness of the sensor design is the fact that introducing the through-hole arrays into the supporting nitride membrane allows generating an increased strain in the graphene membrane over the through-hole array by local deformations of the holes under an applied differential pressure. Further reasons contributing to the increased strain in the devised sensitive membrane include larger deflection of the membrane than that of its imperforated counterpart membrane, and direct bulging of the graphene microdrum under an applied pressure. Electromechanical measurements show a gauge factor of 4.4 for the graphene membrane and a sensitivity of 2.8 × 10-5 mbar-1 for the pressure sensor with a good linearity over a wide pressure range. The present sensor outperforms most existing MEMS-based small footprint pressure sensors using graphene, silicon, and carbon nanotubes as sensitive materials, due to the high sensitivity.

  1. A High Performance Torque Sensor for Milling Based on a Piezoresistive MEMS Strain Gauge

    Directory of Open Access Journals (Sweden)

    Yafei Qin

    2016-04-01

    Full Text Available In high speed and high precision machining applications, it is important to monitor the machining process in order to ensure high product quality. For this purpose, it is essential to develop a dynamometer with high sensitivity and high natural frequency which is suited to these conditions. This paper describes the design, calibration and performance of a milling torque sensor based on piezoresistive MEMS strain. A detailed design study is carried out to optimize the two mutually-contradictory indicators sensitivity and natural frequency. The developed torque sensor principally consists of a thin-walled cylinder, and a piezoresistive MEMS strain gauge bonded on the surface of the sensing element where the shear strain is maximum. The strain gauge includes eight piezoresistances and four are connected in a full Wheatstone circuit bridge, which is used to measure the applied torque force during machining procedures. Experimental static calibration results show that the sensitivity of torque sensor has been improved to 0.13 mv/Nm. A modal impact test indicates that the natural frequency of torque sensor reaches 1216 Hz, which is suitable for high speed machining processes. The dynamic test results indicate that the developed torque sensor is stable and practical for monitoring the milling process.

  2. MEMS sensors for assessing flow-related control of an underwater biomimetic robotic stingray.

    Science.gov (United States)

    Asadnia, Mohsen; Kottapalli, Ajay Giri Prakash; Haghighi, Reza; Cloitre, Audren; Alvarado, Pablo Valdivia Y; Miao, Jianmin; Triantafyllou, Michael

    2015-05-18

    A major difference between manmade underwater robotic vehicles (URVs) and undersea animals is the dense arrays of sensors on the body of the latter which enable them to execute extreme control of their limbs and demonstrate super-maneuverability. There is a high demand for miniaturized, low-powered, lightweight and robust sensors that can perform sensing on URVs to improve their control and maneuverability. In this paper, we present the design, fabrication and experimental testing of two types of microelectromechanical systems (MEMS) sensors that benefit the situational awareness and control of a robotic stingray. The first one is a piezoresistive liquid crystal polymer haircell flow sensor which is employed to determine the velocity of propagation of the stingray. The second one is Pb(Zr(0.52)Ti(0.48))O3 piezoelectric micro-diaphragm pressure sensor which measures various flapping parameters of the stingray's fins that are key parameters to control the robot locomotion. The polymer flow sensors determine that by increasing the flapping frequency of the fins from 0.5 to 3 Hz the average velocity of the stingray increases from 0.05 to 0.4 BL s(-1), respectively. The role of these sensors in detecting errors in control and functioning of the actuators in performing tasks like flapping at a desired amplitude and frequency, swimming at a desired velocity and direction are quantified. The proposed sensors are also used to provide inputs for a model predictive control which allows the robot to track a desired trajectory. Although a robotic stingray is used as a platform to emphasize the role of the MEMS sensors, the applications can be extended to most URVs.

  3. Gas separation membranes for zero-emission fossil power plants: MEM-BRAIN

    NARCIS (Netherlands)

    Czyperek, M.; Zapp, P.; Bouwmeester, Henricus J.M.; Modigell, M.; Ebert, K.; Voigt, I.; Meulenberg, W.A.; Singheiser, L.; Stöver, D.

    2010-01-01

    The objective of the “MEM-BRAIN” project is the development and integration of ceramic and polymeric gas separation membranes for zero-emission fossil power plants. This will be achieved using membranes with a high permeability and selectivity for either CO2, O2 or H2, for the three CO2 capture

  4. MEM-BRAIN gas separation membranes for zero-emission fossil power plants

    NARCIS (Netherlands)

    Czyperek, M.; Zapp, P.; Bouwmeester, Henricus J.M.; Modigell, M.; Peinemann, K.-V.; Voigt, I.; Meulenberg, W.A.; Singheiser, L.; Stöver, D.

    2009-01-01

    The aim of the MEM-BRAIN project is the development and integration of gas separation membranes for zero-emission fossil power plants. This will be achieved by selective membranes with high permeability for CO2, O2 or H2, so that high-purity CO2 is obtained in a readily condensable form. The project

  5. Evaluation of the MEMS based portable respiratory training system with a tactile sensor for respiratory-gated radiotherapy

    Science.gov (United States)

    Moon, Sun Young; Yoon, Myonggeun; Chung, Mijoo; Chung, Weon Kuu; Kim, Dong Wook

    2017-10-01

    In respiratory-gated radiotherapy, it is important to maintain the regular respiratory cycles of patients. If patients undergo respiration training, their regular breathing pattern is affected. Therefore, we developed a respiratory training system based on a micro electromechanical system (MEMS) and evaluated the feasibility of the MEMS in radiotherapy. By comparing the measured signal before and after radiation exposure, we confirmed the effects of radiation. By evaluating the period of the electric signal emitted by a tactile sensor and its constancy, the performance of the tactile sensor was confirmed. Moreover, by comparing the delay between the motion of the MEMS and the electric signal from the tactile sensor, we confirmed the reaction time of the tactile sensor. The results showed that a baseline shift occurred for an accumulated dose of 400 Gy in the sensor, and both the amplitude and period changed. The period of the signal released by the tactile sensor was 5.39 and its standard deviation was 0.06. Considering the errors from the motion phantom, a standard deviation of 0.06 was desirable. The delay time was within 0.5 s and not distinguishable by a patient. We confirmed the performance of the MEMS and concluded that MEMS could be applied to patients for respiratory-gated radiotherapy.

  6. FEM Simulation of Influence of Protective Encapsulation on MEMS Pressure Sensor

    DEFF Research Database (Denmark)

    Yao, Qingshan; Janting, Jakob; Branebjerg, Jens

    2003-01-01

    The objective of the work is to evaluate the feasibility of packaging a MEMS silicon pressure sensor by using either a polymer encapsulation or a combination of a polymer encapsulation and a metallic protection Membrane (fig. 1). The potential application of the protected sensor is for harsh...... compared to the conventionally exposed sensor. 2) Stress concentration calculations are performed to investigate if the encapsulation could lead to increased stress concentration in the silicon structure. The reliability of the adhesion of the metallic encapsulating membrane is assessed by investigating...... whether the metallic membrane / coating will peel off when applying the maximum pressure, which is 4000 bar leading to high shear stress between the metallic membrane and the polymer encapsulation material.3) Thermal calculations are made to evaluate the influence of the environment on the packaged sensor...

  7. A MEMS differential viscometric sensor for affinity glucose detection in continuous glucose monitoring

    International Nuclear Information System (INIS)

    Huang, Xian; Cai, Haogang; Song, Bing; Lin, Qiao; Li, Siqi; Davis, Erin; Wang, Qian; Leduc, Charles; Ravussin, Yann; Leibel, Rudolph; Li, Dachao; Accili, Domenico

    2013-01-01

    Micromachined viscometric affinity glucose sensors have been previously demonstrated using vibrational cantilever and diaphragm. These devices featured a single glucose detection module that determines glucose concentrations through viscosity changes of glucose-sensitive polymer solutions. However, fluctuations in temperature and other environmental parameters might potentially affect the stability and reliability of these devices, creating complexity in their applications in subcutaneously implanted continuous glucose monitoring (CGM). To address these issues, we present a MEMS differential sensor that can effectively reject environmental disturbances while allowing accurate glucose detection. The sensor consists of two magnetically driven vibrating diaphragms situated inside microchambers filled with a boronic-acid based glucose-sensing solution and a reference solution insensitive to glucose. Glucose concentrations can be accurately determined by characteristics of the diaphragm vibration through differential capacitive detection. Our in vitro and preliminary in vivo experimental data demonstrate the potential of this sensor for highly stable subcutaneous CGM applications. (paper)

  8. Bio-inspired MEMS Aquatic Flow Sensor Arrays

    NARCIS (Netherlands)

    Izadi, N.

    2011-01-01

    This thesis describes the attempt to design and fabricate flow sensors based on the function of sensory organs of the lateral line of fish. The driving force is the sensitivity and robustness of these sensory organs and the wide range of engineering appli¬cations that can benefit from direct

  9. Characterization of the MEMS directional sound sensor in the high frequency (15 - 20 kHz) range

    OpenAIRE

    Davis, Darren D.

    2011-01-01

    The Sensor Research Laboratory (SRL) at Naval Postgraduate School (NPS) has developed a micro-electromechanical system (MEMS) based directional sound sensors that mimics the aural system of the Ormia Ochracea Fly. The goal of this research is to characterize a set of directional sound sensors with varying configurations that operate in the high frequency range (15?20 kHz). The sensor consists of two identical wings coupled in the middle and the entire structure is connected to a substrate usi...

  10. Micro-electro-mechanical-system (MEMS)-based fiber optic grating sensor for improving weapon stabilization and fire control

    Science.gov (United States)

    Zhang, Sean Z.; Xu, Guoda; Qui, Wei; Lin, Freddie S.; Testa, Robert C.; Mattice, Michael S.

    2000-06-01

    A MEMS-based fiber optic grating sensor (FOGS) for improving weapon stabilization and fire control has been investigated and developed. The technique overwrites two fiber Bragg gratings (FBGs) onto a polarization-preserving optical fiber core. A MEMS diaphragm is fabricated and integrated with the overlaid FBGs to enhance the performance and reliability of the sensor. A simulation model for the MEMS-FOGS was derived, and simulation results concerning load, angle, strain, and temperature were obtained. The fabricated MEMS diaphragm and the overlaid FBGs are packaged together and mounted on a specially designed cantilever beam system. User-friendly software for sensing system design and data analysis has been developed and can be used to control other sensing systems. The combined multifunctional sensitive. The fully developed sensing system is expected to find applications in fire control, weapon stabilization, and other areas where accurately sensing strain and temperature is critical.

  11. A novel optimal configuration form redundant MEMS inertial sensors based on the orthogonal rotation method.

    Science.gov (United States)

    Cheng, Jianhua; Dong, Jinlu; Landry, Rene; Chen, Daidai

    2014-07-29

    In order to improve the accuracy and reliability of micro-electro mechanical systems (MEMS) navigation systems, an orthogonal rotation method-based nine-gyro redundant MEMS configuration is presented. By analyzing the accuracy and reliability characteristics of an inertial navigation system (INS), criteria for redundant configuration design are introduced. Then the orthogonal rotation configuration is formed through a two-rotation of a set of orthogonal inertial sensors around a space vector. A feasible installation method is given for the real engineering realization of this proposed configuration. The performances of the novel configuration and another six configurations are comprehensively compared and analyzed. Simulation and experimentation are also conducted, and the results show that the orthogonal rotation configuration has the best reliability, accuracy and fault detection and isolation (FDI) performance when the number of gyros is nine.

  12. Design and Fabrication of a Miniaturized GMI Magnetic Sensor Based on Amorphous Wire by MEMS Technology.

    Science.gov (United States)

    Chen, Jiawen; Li, Jianhua; Li, Yiyuan; Chen, Yulong; Xu, Lixin

    2018-03-01

    A miniaturized Co-based amorphous wire GMI (Giant magneto-impedance) magnetic sensor was designed and fabricated in this paper. The Co-based amorphous wire was used as the sense element due to its high sensitivity to the magnetic field. A three-dimensional micro coil surrounding the Co-based amorphous wire was fabricated by MEMS (Micro-Electro-Mechanical System) technology, which was used to extract the electrical signal. The three-dimensional micro pick-up coil was designed and simulated with HFSS (High Frequency Structure Simulator) software to determine the key parameters. Surface micro machining MEMS (Micro-Electro-Mechanical System) technology was employed to fabricate the three-dimensional coil. The size of the developed amorphous wire magnetic sensor is 5.6 × 1.5 × 1.1 mm³. Helmholtz coil was used to characterize the performance of the device. The test results of the sensor sample show that the voltage change is 130 mV/Oe and the linearity error is 4.83% in the range of 0~45,000 nT. The results indicate that the developed miniaturized magnetic sensor has high sensitivity. By testing the electrical resistance of the samples, the results also showed high uniformity of each device.

  13. Design of a MEMS piezoresistive differential pressure sensor with small thermal hysteresis for air data modules.

    Science.gov (United States)

    Song, Jin Woo; Lee, Jang-Sub; An, Jun-Eon; Park, Chan Gook

    2015-06-01

    The design, fabrication, and evaluation results of a MEMS piezoresistive differential pressure sensor fabricated by the dry etching process are described in this paper. The proposed sensor is designed to have optimal performances in mid-pressure range from 0 psi to 20 psi suitable for a precision air data module. The piezoresistors with a Wheatstone bridge structure are implanted where the thermal effects are minimized subject to sustainment of the sensitivity. The rectangular-shaped silicon diaphragm is adopted and its dimension is analyzed for improving pressure sensitivity and linearity. The bridge resistors are driven by constant current to compensate temperature effects on sensitivity. The designed differential pressure sensor is fabricated by using MEMS dry etching techniques, and the fabricated sensing element is attached and packaged in a Kovar package in consideration of leakage and temperature hysteresis. The implemented sensors are tested and evaluated as well. The evaluation results show the static RSS (root sum square) accuracy including nonlinearity, non-repeatability, and pressure hysteresis before temperature compensation is about 0.09%, and the total error band which includes the RSS accuracy, the thermal hysteresis, and other thermal effects is about 0.11%, which confirm the validity of the proposed design process.

  14. Design and Fabrication of a Miniaturized GMI Magnetic Sensor Based on Amorphous Wire by MEMS Technology

    Directory of Open Access Journals (Sweden)

    Jiawen Chen

    2018-03-01

    Full Text Available A miniaturized Co-based amorphous wire GMI (Giant magneto-impedance magnetic sensor was designed and fabricated in this paper. The Co-based amorphous wire was used as the sense element due to its high sensitivity to the magnetic field. A three-dimensional micro coil surrounding the Co-based amorphous wire was fabricated by MEMS (Micro-Electro-Mechanical System technology, which was used to extract the electrical signal. The three-dimensional micro pick-up coil was designed and simulated with HFSS (High Frequency Structure Simulator software to determine the key parameters. Surface micro machining MEMS (Micro-Electro-Mechanical System technology was employed to fabricate the three-dimensional coil. The size of the developed amorphous wire magnetic sensor is 5.6 × 1.5 × 1.1 mm3. Helmholtz coil was used to characterize the performance of the device. The test results of the sensor sample show that the voltage change is 130 mV/Oe and the linearity error is 4.83% in the range of 0~45,000 nT. The results indicate that the developed miniaturized magnetic sensor has high sensitivity. By testing the electrical resistance of the samples, the results also showed high uniformity of each device.

  15. Design of a Base Station for MEMS CCR Localization in an Optical Sensor Network

    Directory of Open Access Journals (Sweden)

    Chan Gook Park

    2014-05-01

    Full Text Available This paper introduces a design and implementation of a base station, capable of positioning sensor nodes using an optical scheme. The base station consists of a pulse laser module, optical detectors and beam splitter, which are mounted on a rotation-stage, and a Time to Digital Converter (TDC. The optical pulse signal transmitted to the sensor node with a Corner Cube Retro-reflector (CCR is reflected to the base station, and the Time of Flight (ToF data can be obtained from the two detectors. With the angle and flight time data, the position of the sensor node can be calculated. The performance of the system is evaluated by using a commercial CCR. The sensor nodes are placed at different angles from the base station and scanned using the laser. We analyze the node position error caused by the rotation and propose error compensation methods, namely the outlier sample exception and decreasing the confidence factor steadily using the recursive least square (RLS methods. Based on the commercial CCR results, the MEMS CCR is also tested to demonstrate the compatibility between the base station and the proposed methods. The result shows that the localization performance of the system can be enhanced with the proposed compensation method using the MEMS CCR.

  16. Design of a base station for MEMS CCR localization in an optical sensor network.

    Science.gov (United States)

    Park, Chan Gook; Jeon, Hyun Cheol; Kim, Hyoun Jin; Kim, Jae Yoon

    2014-05-08

    This paper introduces a design and implementation of a base station, capable of positioning sensor nodes using an optical scheme. The base station consists of a pulse laser module, optical detectors and beam splitter, which are mounted on a rotation-stage, and a Time to Digital Converter (TDC). The optical pulse signal transmitted to the sensor node with a Corner Cube Retro-reflector (CCR) is reflected to the base station, and the Time of Flight (ToF) data can be obtained from the two detectors. With the angle and flight time data, the position of the sensor node can be calculated. The performance of the system is evaluated by using a commercial CCR. The sensor nodes are placed at different angles from the base station and scanned using the laser. We analyze the node position error caused by the rotation and propose error compensation methods, namely the outlier sample exception and decreasing the confidence factor steadily using the recursive least square (RLS) methods. Based on the commercial CCR results, the MEMS CCR is also tested to demonstrate the compatibility between the base station and the proposed methods. The result shows that the localization performance of the system can be enhanced with the proposed compensation method using the MEMS CCR.

  17. Simulasi Sensor Seismometer Horizontal Menggunakan MEMS Accelerometer Berbasis Arduino UNO

    OpenAIRE

    Hutapea, Cynthya Dorothy

    2017-01-01

    130801045 Telah dirancang sebuah alat sebagai seismometer horizontal menggunakan GY-521 dan Arduino UNO ATMEGA 328P. Alat ini terdiri dari GY-521 modul MPU-6050 sebagai sensor vibrasi dan arduino UNO sebagai pengendali sistem. Perangkat lunak yang digunakan sebagai pengendali sistem adalah Arduino IDE. Cara kerja alat tersebut cukup sederhana yaitu accelerometer MPU-6050 mengukur amplitudo dan frekuensi dari kecepatan suatu getaran dan kemudian datanya akan dikirim ke arduino. Arduino UNO ...

  18. MEMS Based Pressure Sensors – Linearity and Sensitivity Issues

    Directory of Open Access Journals (Sweden)

    Jaspreet Singh

    2008-04-01

    Full Text Available This paper describes the various nonlinearities (NL encountered in the Si-based Piezoresistive pressure sensors. The effect of various factors like diaphragm thickness, diaphragm curvature, position of the piezoresistors etc. is analyzed taking anisotropy into account. Also, the effect of modified bending stiffness due to presence of oxide/nitride used for isolation between metal and diaphragm is studied from linearity point of view.

  19. Structural health monitoring MEMS sensors using elasticity-based beam vibrations

    Science.gov (United States)

    Plankis, Alivia

    The worsening problem of aging and deficient infrastructure in this nation and across the world has demonstrated the need for an improved system to monitor and maintain these structures. The field of structural health monitoring has grown in recent years to address this issue. The goal of this field is to continually monitor the condition of a structure to detect and mitigate damage that may occur. Many structural health monitoring methods have been developed and most of these require sensor systems to collect the necessary information to assess the current strength and integrity of a structure. The motivation for this thesis is a proposed new microelectromechanical systems (MEMS) sensor with applications in civil infrastructure sensing. The work required was to determine accurate estimates of the resonant frequencies for a fixed-fixed silicon bridge within the device so that further testing and development could proceed. Additional knowledge and information were essential, though, before these requested calculations could be performed confidently. First, a thorough review of current structural health monitoring concepts and methods was performed to better understand the field in which this device would be applied and what incentive existed to develop a new sensor. Second, an in-depth investigation of vibrational beam mechanics theories was completed to ensure the accuracy of the frequency results for the new MEMS sensor. This study analyzed the influence of three assumptions employed in the Euler-Bernoulli, Rayleigh, and Timoshenko beam theories by comparing their results to a three-dimensional, elasticity-based approximation for vibrational frequencies and mode shapes. The results of this study showed that all three theories are insufficient when a fixed support is involved, so the elasticity-based approximation was utilized to calculate the frequencies for the bridge component in the MEMS device. These results have been passed on to the developers so that the

  20. Attachment of MEM piezoresistive silicon pressure sensor dies using different adhesives

    Directory of Open Access Journals (Sweden)

    Jović Vesna B.

    2011-01-01

    Full Text Available This paper gives comparison and discussion of adhesives used for attachment of silicon piezoresistive pressure sensor dies. Special attention is paid on low pressure sensor dies because of their extreme sensitivity on stresses, which can arise from packaging procedure and applied materials. Commercially available adhesives “Scotch Weld 2214 Hi-Temp” from “3M Co.” and “DM2700P/H848” from “DIEMAT”, USA, were compared. First of them is aluminum filled epoxy adhesive and second is low melting temperature (LMT glass paste. Comparing test results for low pressure sensor chips we found that LMT glass (glass frit is better adhesive for this application. Applying LMT glass paste minimizes internal stresses caused by disagreement of coefficients of thermal expansions between sensor die and housing material. Also, it minimizes stresses introduced during applying external loads in the process of pressure measuring. Regarding the measurements, for the sensors installed with filled epoxy paste, resistor for compensation of temperature offset change had negative values in all cases, which means that linear temperature compensation, of sensors installed this way, would be impossible. In the sensors installed with LMT glass paste, all results, without exception, were in their common limits (values, which give the possibility of passive temperature compensation. Furthermore, LMT glass attachment can broaden temperature operating range of MEM silicon pressure sensors towards higher values, up to 120 ºC.

  1. Gas sensor with attenuated drift characteristic

    Science.gov (United States)

    Chen, Ing-Shin [Danbury, CT; Chen, Philip S. H. [Bethel, CT; Neuner, Jeffrey W [Bethel, CT; Welch, James [Fairfield, CT; Hendrix, Bryan [Danbury, CT; Dimeo, Jr., Frank [Danbury, CT

    2008-05-13

    A sensor with an attenuated drift characteristic, including a layer structure in which a sensing layer has a layer of diffusional barrier material on at least one of its faces. The sensor may for example be constituted as a hydrogen gas sensor including a palladium/yttrium layer structure formed on a micro-hotplate base, with a chromium barrier layer between the yttrium layer and the micro-hotplate, and with a tantalum barrier layer between the yttrium layer and an overlying palladium protective layer. The gas sensor is useful for detection of a target gas in environments susceptible to generation or incursion of such gas, and achieves substantial (e.g., >90%) reduction of signal drift from the gas sensor in extended operation, relative to a corresponding gas sensor lacking the diffusional barrier structure of the invention

  2. Gas Sensors Based on Conducting Polymers

    Directory of Open Access Journals (Sweden)

    Gaoquan Shi

    2007-03-01

    Full Text Available The gas sensors fabricated by using conducting polymers such as polyaniline (PAni, polypyrrole (PPy and poly (3,4-ethylenedioxythiophene (PEDOT as the active layers have been reviewed. This review discusses the sensing mechanism and configurations of the sensors. The factors that affect the performances of the gas sensors are also addressed. The disadvantages of the sensors and a brief prospect in this research field are discussed at the end of the review.

  3. From nature to MEMS: towards the detection-limit of crickets' hair sensors

    Science.gov (United States)

    Dagamseh, A. M. K.

    2013-05-01

    Crickets use highly sensitive mechanoreceptor hairs to detect approaching spiders. The high sensitivity of these hairs enables perceiving tiny air-movements which are only just distinguishable from noise. This forms our source of inspiration to design sensitive arrays made of artificial hair sensors for flow pattern observation i.e. Flow camera. The realization of such high-sensitive hair sensor requires designs with low thermo-mechanical noise to match the detection-limit of crickets' hairs. Here we investigate the damping factor in our artificial hair-sensor using different models as it is the source of the thermo-mechanical noise in MEMS structures. The results show that the damping factor estimated in air is in the range of 10-12 N.m/rad.s-1 which translates into a 52 μm/s threshold flow velocity.

  4. Specialized hybrid batch fabrication process for MEMS RF voltage sensors

    Science.gov (United States)

    Dittmer, Jan; Judaschke, Rolf; Büttgenbach, Stephanus

    2007-12-01

    RF voltage measurement based on electrostatic RMS voltage-to-force conversion is an alternative method in comparison to the classical thermal power dissipation method. It is based on a parallel-plate capacitor with one elastically hinged plate. By applying an AC voltage, a force proportional to its RMS value is generated between the plates, and consequently the movable plate swings to the equilibrium position between spring force and electrostatic force. For a theoretically adequate resolution and precision, the necessary geometrical dimensions of the sensor practically require the use of advanced micromachining techniques. In this contribution, we discuss a unique batch fabrication process to meet the challenge of having two very large plane-parallel surfaces separated by only a few microns. The basic design consists of an actuator made of silicon embedded between two glass wafers for electrical contacting and sealing. Each step of this hybrid process has been optimized to prevent residual liquids leading to stiction and breaking of the fragile parts of the micro-structures. Flat grooves in the silicon define the gap between the capacitor electrodes, and an anisotropic dry-etch step releases the actuator. A second glass wafer builds the top of the stack and is fixated using a patterned photo-resist. Bumpers on the bottom layer and ridges in the top wafer improve the robustness of the structure. In this paper, we present a detailed analysis of the production process, pointing out critical as well as alternative design steps towards the optimized sensor. Finally, results of working devices are shown.

  5. Experimental investigation of parametric and externally forced motion in resonant MEMS sensors

    International Nuclear Information System (INIS)

    Harish, K M; Gallacher, B J; Burdess, J S; Neasham, J A

    2009-01-01

    In this paper an excitation method employing both harmonic forcing and parametric excitation is applied to a resonant MEMS sensor in order to investigate and characterize the phenomena of parametric resonance and parametric amplification. The motivation for this research is that parametric excitation may be used to significantly reduce the total damping in MEMS sensors in a controllable manner. This is extremely pertinent to devices where the Q-factor is a principal factor in determining sensor performance. In this paper it is shown that, by adjusting the parametric excitation parameters (frequency, amplitude and phase) of an electrostatically actuated and sensed device, the gain of the frequency response function of a mode of vibration may be amplified. The amplification is quantified by the gain factor which is characterized experimentally. The instability regions defining the regions for parametric resonance are also characterized experimentally and compared to theoretical predictions. The boundaries of these instability regions define the thresholds for parametric resonance and play a crucial role in the design of the parametric amplifier

  6. Distortion-free measurement of electric field strength with a MEMS sensor.

    Science.gov (United States)

    Kainz, Andreas; Steiner, Harald; Schalko, Johannes; Jachimowicz, Artur; Kohl, Franz; Stifter, Michael; Beigelbeck, Roman; Keplinger, Franz; Hortschitz, Wilfried

    2018-01-08

    Small-scale and distortion-free measurement of electric fields is crucial for applications such as surveying atmospheric electrostatic fields, lightning research, and safeguarding areas close to high-voltage power lines. A variety of measurement systems exist, the most common of which are field mills, which work by picking up the differential voltage of the measurement electrodes while periodically shielding them with a grounded electrode. However, all current approaches are either bulky, suffer from a strong temperature dependency, or severely distort the electric field requiring a well-defined surrounding and complex calibration procedures. Here we show that microelectromechanical system (MEMS) devices can be used to measure electric field strength without significant field distortion. The purely passive MEMS devices exploit the effect of electrostatic induction, which is used to generate internal forces that are converted into an optically tracked mechanical displacement of a spring-suspended seismic mass. The devices exhibit resolutions on the order of [Formula: see text] with a measurement range of up to tens of kilovolt per metre in the quasi-static regime (≲ 300 Hz).We also show that it should be possible to achieve resolutions of around [Formula: see text] by fine-tuning of the sensor embodiment. These MEMS devices are compact and could easily be mass produced for wide application.

  7. DOUBLE BOSS SCULPTURED DIAPHRAGM EMPLOYED PIEZORESISTIVE MEMS PRESSURE SENSOR WITH SILICON-ON-INSULATOR (SOI

    Directory of Open Access Journals (Sweden)

    D. SINDHANAISELVI

    2017-07-01

    Full Text Available This paper presents the detailed study on the measurement of low pressure sensor using double boss sculptured diaphragm of piezoresistive type with MEMS technology in flash flood level measurement. The MEMS based very thin diaphragms to sense the low pressure is analyzed by introducing supports to achieve linearity. The simulation results obtained from Intellisuite MEMS CAD design tool show that very thin diaphragms with rigid centre or boss give acceptable linearity. Further investigations on very thin diaphragms embedded with piezoresistor for low pressure measurement show that it is essential to analyse the piezoresistor placement and size of piezoresistor to achieve good sensitivity. A modified analytical modelling developed in this study for double boss sculptured diaphragm results were compared with simulated results. Further the enhancement of sensitivity is analyzed using non uniform thickness diaphragm and Silicon-On-Insulator (SOI technique. The simulation results indicate that the double boss square sculptured diaphragm with SOI layer using 0.85μm thickness yields the higher voltage sensitivity, acceptable linearity with Small Scale Deflection.

  8. Vision sensor and dual MEMS gyroscope integrated system for attitude determination on moving base

    Science.gov (United States)

    Guo, Xiaoting; Sun, Changku; Wang, Peng; Huang, Lu

    2018-01-01

    To determine the relative attitude between the objects on a moving base and the base reference system by a MEMS (Micro-Electro-Mechanical Systems) gyroscope, the motion information of the base is redundant, which must be removed from the gyroscope. Our strategy is to add an auxiliary gyroscope attached to the reference system. The master gyroscope is to sense the total motion, and the auxiliary gyroscope is to sense the motion of the moving base. By a generalized difference method, relative attitude in a non-inertial frame can be determined by dual gyroscopes. With the vision sensor suppressing accumulative drift of the MEMS gyroscope, the vision and dual MEMS gyroscope integration system is formed. Coordinate system definitions and spatial transform are executed in order to fuse inertial and visual data from different coordinate systems together. And a nonlinear filter algorithm, Cubature Kalman filter, is used to fuse slow visual data and fast inertial data together. A practical experimental setup is built up and used to validate feasibility and effectiveness of our proposed attitude determination system in the non-inertial frame on the moving base.

  9. The Evolution of High Temperature Gas Sensors.

    Energy Technology Data Exchange (ETDEWEB)

    Garzon, F. H. (Fernando H.); Brosha, E. L. (Eric L.); Mukundan, R. (Rangachary)

    2001-01-01

    Gas sensor technology based on high temperature solid electrolytes is maturing rapidly. Recent advances in metal oxide catalysis and thin film materials science has enabled the design of new electrochemical sensors. We have demonstrated prototype amperometric oxygen sensors, nernstian potentiometric oxygen sensors that operate in high sulfur environments, and hydrocarbon and carbon monoxide sensing mixed potentials sensors. Many of these devices exhibit part per million sensitivities, response times on the order of seconds and excellent long-term stability.

  10. A Holistic Approach to Automated Synthesis of Mixed-technology Digital MEMS Sensors Part 2: Synthesis of a MEMS System with Associated Control Loop

    Directory of Open Access Journals (Sweden)

    Chenxu ZHAO

    2010-06-01

    Full Text Available Part 2 of this paper presents a holistic synthesis approach to designing both the mechanical layout and associated electronic control in a mixed-domain MEMS sensor. It develops further the concepts presented in Part 1 which focuses on layout synthesis of the mechanical part only. A case study is discussed where the proposed genetic-based synthesis approach implemented in SystemC-AGNES is applied to a high order ΣΔ control system in an electromechanical MEMS accelerometer. The method efficiently and in an automated manner generates suitable configurations of the ΣΔ control loop by combining primitive components stored in a library and optimizes them according to user specifications. The synthesis results show that the proposed technique explores the configuration space effectively and it develops new circuit structures which have not been investigated before. The noise floors in the MEMS accelerometers synthesized by SystemC-AGNES are further reduced leading to an improvement of the SNR compared with a manually designed standard electromechanical ΣΔ MEMS accelerometer.

  11. Laboratory validation of MEMS-based sensors for post-earthquake damage assessment image

    Science.gov (United States)

    Pozzi, Matteo; Zonta, Daniele; Santana, Juan; Colin, Mikael; Saillen, Nicolas; Torfs, Tom; Amditis, Angelos; Bimpas, Matthaios; Stratakos, Yorgos; Ulieru, Dumitru; Bairaktaris, Dimitirs; Frondistou-Yannas, Stamatia; Kalidromitis, Vasilis

    2011-04-01

    The evaluation of seismic damage is today almost exclusively based on visual inspection, as building owners are generally reluctant to install permanent sensing systems, due to their high installation, management and maintenance costs. To overcome this limitation, the EU-funded MEMSCON project aims to produce small size sensing nodes for measurement of strain and acceleration, integrating Micro-Electro-Mechanical Systems (MEMS) based sensors and Radio Frequency Identification (RFID) tags in a single package that will be attached to reinforced concrete buildings. To reduce the impact of installation and management, data will be transmitted to a remote base station using a wireless interface. During the project, sensor prototypes were produced by assembling pre-existing components and by developing ex-novo miniature devices with ultra-low power consumption and sensing performance beyond that offered by sensors available on the market. The paper outlines the device operating principles, production scheme and working at both unit and network levels. It also reports on validation campaigns conducted in the laboratory to assess system performance. Accelerometer sensors were tested on a reduced scale metal frame mounted on a shaking table, back to back with reference devices, while strain sensors were embedded in both reduced and full-scale reinforced concrete specimens undergoing increasing deformation cycles up to extensive damage and collapse. The paper assesses the economical sustainability and performance of the sensors developed for the project and discusses their applicability to long-term seismic monitoring.

  12. Artificial Roughness Encoding with a Bio-inspired MEMS- based Tactile Sensor Array

    Science.gov (United States)

    Oddo, Calogero Maria; Beccai, Lucia; Felder, Martin; Giovacchini, Francesco; Carrozza, Maria Chiara

    2009-01-01

    A compliant 2×2 tactile sensor array was developed and investigated for roughness encoding. State of the art cross shape 3D MEMS sensors were integrated with polymeric packaging providing in total 16 sensitive elements to external mechanical stimuli in an area of about 20 mm2, similarly to the SA1 innervation density in humans. Experimental analysis of the bio-inspired tactile sensor array was performed by using ridged surfaces, with spatial periods from 2.6 mm to 4.1 mm, which were indented with regulated 1N normal force and stroked at constant sliding velocity from 15 mm/s to 48 mm/s. A repeatable and expected frequency shift of the sensor outputs depending on the applied stimulus and on its scanning velocity was observed between 3.66 Hz and 18.46 Hz with an overall maximum error of 1.7%. The tactile sensor could also perform contact imaging during static stimulus indentation. The experiments demonstrated the suitability of this approach for the design of a roughness encoding tactile sensor for an artificial fingerpad. PMID:22412304

  13. Artificial Roughness Encoding with a Bio-inspired MEMS-based Tactile Sensor Array

    Directory of Open Access Journals (Sweden)

    Calogero Maria Oddo

    2009-04-01

    Full Text Available A compliant 2x2 tactile sensor array was developed and investigated for roughness encoding. State of the art cross shape 3D MEMS sensors were integrated with polymeric packaging providing in total 16 sensitive elements to external mechanical stimuli in an area of about 20 mm2, similarly to the SA1 innervation density in humans. Experimental analysis of the bio-inspired tactile sensor array was performed by using ridged surfaces, with spatial periods from 2.6 mm to 4.1 mm, which were indented with regulated 1N normal force and stroked at constant sliding velocity from 15 mm/s to 48 mm/s. A repeatable and expected frequency shift of the sensor outputs depending on the applied stimulus and on its scanning velocity was observed between 3.66 Hz and 18.46 Hz with an overall maximum error of 1.7%. The tactile sensor could also perform contact imaging during static stimulus indentation. The experiments demonstrated the suitability of this approach for the design of a roughness encoding tactile sensor for an artificial fingerpad.

  14. Statistical Sensor Fusion of a 9-DOF Mems Imu for Indoor Navigation

    Science.gov (United States)

    Chow, J. C. K.

    2017-09-01

    Sensor fusion of a MEMS IMU with a magnetometer is a popular system design, because such 9-DoF (degrees of freedom) systems are capable of achieving drift-free 3D orientation tracking. However, these systems are often vulnerable to ambient magnetic distortions and lack useful position information; in the absence of external position aiding (e.g. satellite/ultra-wideband positioning systems) the dead-reckoned position accuracy from a 9-DoF MEMS IMU deteriorates rapidly due to unmodelled errors. Positioning information is valuable in many satellite-denied geomatics applications (e.g. indoor navigation, location-based services, etc.). This paper proposes an improved 9-DoF IMU indoor pose tracking method using batch optimization. By adopting a robust in-situ user self-calibration approach to model the systematic errors of the accelerometer, gyroscope, and magnetometer simultaneously in a tightly-coupled post-processed least-squares framework, the accuracy of the estimated trajectory from a 9-DoF MEMS IMU can be improved. Through a combination of relative magnetic measurement updates and a robust weight function, the method is able to tolerate a high level of magnetic distortions. The proposed auto-calibration method was tested in-use under various heterogeneous magnetic field conditions to mimic a person walking with the sensor in their pocket, a person checking their phone, and a person walking with a smartwatch. In these experiments, the presented algorithm improved the in-situ dead-reckoning orientation accuracy by 79.8-89.5 % and the dead-reckoned positioning accuracy by 72.9-92.8 %, thus reducing the relative positioning error from metre-level to decimetre-level after ten seconds of integration, without making assumptions about the user's dynamics.

  15. STATISTICAL SENSOR FUSION OF A 9-DOF MEMS IMU FOR INDOOR NAVIGATION

    Directory of Open Access Journals (Sweden)

    J. C. K. Chow

    2017-09-01

    Full Text Available Sensor fusion of a MEMS IMU with a magnetometer is a popular system design, because such 9-DoF (degrees of freedom systems are capable of achieving drift-free 3D orientation tracking. However, these systems are often vulnerable to ambient magnetic distortions and lack useful position information; in the absence of external position aiding (e.g. satellite/ultra-wideband positioning systems the dead-reckoned position accuracy from a 9-DoF MEMS IMU deteriorates rapidly due to unmodelled errors. Positioning information is valuable in many satellite-denied geomatics applications (e.g. indoor navigation, location-based services, etc.. This paper proposes an improved 9-DoF IMU indoor pose tracking method using batch optimization. By adopting a robust in-situ user self-calibration approach to model the systematic errors of the accelerometer, gyroscope, and magnetometer simultaneously in a tightly-coupled post-processed least-squares framework, the accuracy of the estimated trajectory from a 9-DoF MEMS IMU can be improved. Through a combination of relative magnetic measurement updates and a robust weight function, the method is able to tolerate a high level of magnetic distortions. The proposed auto-calibration method was tested in-use under various heterogeneous magnetic field conditions to mimic a person walking with the sensor in their pocket, a person checking their phone, and a person walking with a smartwatch. In these experiments, the presented algorithm improved the in-situ dead-reckoning orientation accuracy by 79.8–89.5 % and the dead-reckoned positioning accuracy by 72.9–92.8 %, thus reducing the relative positioning error from metre-level to decimetre-level after ten seconds of integration, without making assumptions about the user’s dynamics.

  16. Design, Fabrication, and Implementation of an Array-Type MEMS Piezoresistive Intelligent Pressure Sensor System

    Directory of Open Access Journals (Sweden)

    Jiahong Zhang

    2018-02-01

    Full Text Available To meet the radiosonde requirement of high sensitivity and linearity, this study designs and implements a monolithically integrated array-type piezoresistive intelligent pressure sensor system which is made up of two groups of four pressure sensors with the pressure range of 0–50 kPa and 0–100 kPa respectively. First, theoretical models and ANSYS (version 14.5, Canonsburg, PA, USA finite element method (FEM are adopted to optimize the parameters of array sensor structure. Combing with FEM stress distribution results, the size and material characteristics of the array-type sensor are determined according to the analysis of the sensitivity and the ratio of signal to noise (SNR. Based on the optimized parameters, the manufacture and packaging of array-type sensor chips are then realized by using the standard complementary metal-oxide-semiconductor (CMOS and microelectromechanical system (MEMS process. Furthermore, an intelligent acquisition and processing system for pressure and temperature signals is achieved. The S3C2440A microprocessor (Samsung, Seoul, Korea is regarded as the core part which can be applied to collect and process data. In particular, digital signal storage, display and transmission are realized by the application of a graphical user interface (GUI written in QT/E. Besides, for the sake of compensating the temperature drift and nonlinear error, the data fusion technique is proposed based on a wavelet neural network improved by genetic algorithm (GA-WNN for average measuring signal. The GA-WNN model is implemented in hardware by using a S3C2440A microprocessor. Finally, the results of calibration and test experiments achieved with the temperature ranges from −20 to 20 °C show that: (1 the nonlinear error and the sensitivity of the array-type pressure sensor are 8330 × 10−4 and 0.052 mV/V/kPa in the range of 0–50 kPa, respectively; (2 the nonlinear error and the sensitivity are 8129 × 10−4 and 0.020 mV/V/kPa in the

  17. Development of an Emergency Locking Unit for a Belt-In-Seat (BIS System Using a MEMS Acceleration Sensor

    Directory of Open Access Journals (Sweden)

    Chang Hyun Baek

    2010-04-01

    Full Text Available This paper proposes an emergency locking unit (ELU for a seat belt retractor which is mounted on the back frame of a vehicle seat. The proposed unit uses a recliner sensor based on a MEMS acceleration sensor and solenoid mechanism. The seat has an upper frame supported to tilt on a lower frame. The retractor in belt in seat (BIS system is supported by the upper frame. The proposed recliner sensor based on a MEMS acceleration sensor comprises orientation means for maintaining a predetermined orientation of emergency relative to the lower frame independently of the force of gravity when the upper frame tilts on the lower frame. Experimental results show that the developed recliner sensor unit operates effectively with respect to rollover angles. Thus, the developed unit will have a considerable potential to offer a new design concept in BIS system.

  18. Current trends in research on gas sensors

    International Nuclear Information System (INIS)

    Mohd Mustamam A, Karim; John Ojur Dennis; Md Rahim Sahar; Mohd Khairi Saidin

    1998-01-01

    This paper reviews the current trends in researches on gas sensors by considering the techniques and methods for improvement of the performance of semiconductor gas sensors and reporting the newly emerging researches on the detection of gases at the part per million (ppb) levels and photoconduction (author)

  19. Sensor platform for gas composition measurement

    NARCIS (Netherlands)

    De Graaf, G.; Bakker, F.; Wolffenbuttel, R.F.

    2011-01-01

    The gas sensor research presented here has a focus on the measurement of the composition of natural gas and gases from sustainable resources, such as biogas. For efficient and safe combustion, new sensor systems need to be developed to measure the composition of these new gases. In general about 6

  20. Design of Diaphragm Based MEMS Pressure Sensor with Sensitivity Analysis for Environmental Applications

    Directory of Open Access Journals (Sweden)

    A. Nallathambi

    2015-05-01

    Full Text Available In this paper Micro-electromechanical System (MEMS diaphragm based pressure sensor for environmental applications is discussed. The main focus of this paper is to design, simulate and analyze the sensitivity of MEMS based diaphragm using different structures to measure the low and high pressure values. The simulation is done through the finite element tool and specifications related the maximum convinced stress; deflection and sensitivity of the diaphragms have been analyzed using the software INTELLISUITE 8.7v. The change in pressure is to bending of the diaphragm that modifies the measured displacement between the substrate and the diaphragm. This change in displacement gives the measure of the pressure in that environment. The design of these studies can be used to improve the sensitivity of these devices. Here the diaphragm based pressure sensor produced better displacement, sensitivity and stress output responses are obtained from the square diaphragm. The pressure range from 0.6 MPa to 25 MPa and its maximum displacement is accordingly 59 mm over a pressure range of 0 to 2 MPa. Its sensitivity is therefore 2.35 [10E-12/Pa].

  1. Modeling and optimal design of an optical MEMS tactile sensor for use in robotically assisted surgery

    Science.gov (United States)

    Ahmadi, Roozbeh; Kalantari, Masoud; Packirisamy, Muthukumaran; Dargahi, Javad

    2010-06-01

    Currently, Minimally Invasive Surgery (MIS) performs through keyhole incisions using commercially available robotic surgery systems. One of the most famous examples of these robotic surgery systems is the da Vinci surgical system. In the current robotic surgery systems like the da Vinci, surgeons are faced with problems such as lack of tactile feedback during the surgery. Therefore, providing a real-time tactile feedback from interaction between surgical instruments and tissue can help the surgeons to perform MIS more reliably. The present paper proposes an optical tactile sensor to measure the contact force between the bio-tissue and the surgical instrument. A model is proposed for simulating the interaction between a flexible membrane and bio-tissue based on the finite element methods. The tissue is considered as a hyperelastic material with the material properties similar to the heart tissue. The flexible membrane is assumed as a thin layer of silicon which can be microfabricated using the technology of Micro Electro Mechanical Systems (MEMS). The simulation results are used to optimize the geometric design parameters of a proposed MEMS tactile sensor for use in robotic surgical systems to perform MIS.

  2. Digital signal processing by virtual instrumentation of a MEMS magnetic field sensor for biomedical applications.

    Science.gov (United States)

    Juárez-Aguirre, Raúl; Domínguez-Nicolás, Saúl M; Manjarrez, Elías; Tapia, Jesús A; Figueras, Eduard; Vázquez-Leal, Héctor; Aguilera-Cortés, Luz A; Herrera-May, Agustín L

    2013-11-05

    We present a signal processing system with virtual instrumentation of a MEMS sensor to detect magnetic flux density for biomedical applications. This system consists of a magnetic field sensor, electronic components implemented on a printed circuit board (PCB), a data acquisition (DAQ) card, and a virtual instrument. It allows the development of a semi-portable prototype with the capacity to filter small electromagnetic interference signals through digital signal processing. The virtual instrument includes an algorithm to implement different configurations of infinite impulse response (IIR) filters. The PCB contains a precision instrumentation amplifier, a demodulator, a low-pass filter (LPF) and a buffer with operational amplifier. The proposed prototype is used for real-time non-invasive monitoring of magnetic flux density in the thoracic cage of rats. The response of the rat respiratory magnetogram displays a similar behavior as the rat electromyogram (EMG).

  3. Digital Signal Processing by Virtual Instrumentation of a MEMS Magnetic Field Sensor for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Héctor Vázquez-Leal

    2013-11-01

    Full Text Available We present a signal processing system with virtual instrumentation of a MEMS sensor to detect magnetic flux density for biomedical applications. This system consists of a magnetic field sensor, electronic components implemented on a printed circuit board (PCB, a data acquisition (DAQ card, and a virtual instrument. It allows the development of a semi-portable prototype with the capacity to filter small electromagnetic interference signals through digital signal processing. The virtual instrument includes an algorithm to implement different configurations of infinite impulse response (IIR filters. The PCB contains a precision instrumentation amplifier, a demodulator, a low-pass filter (LPF and a buffer with operational amplifier. The proposed prototype is used for real-time non-invasive monitoring of magnetic flux density in the thoracic cage of rats. The response of the rat respiratory magnetogram displays a similar behavior as the rat electromyogram (EMG.

  4. Differential pressure measurement using a free-flying insect-like ornithopter with an MEMS sensor

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Hidetoshi; Aoyama, Yuichiro; Ohsawa, Kazuharu; Iwase, Eiji; Matsumoto, Kiyoshi; Shimoyama, Isao [Department of Mechano-Informatics, Graduate School of Information Science and Technology, University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Tanaka, Hiroto, E-mail: isao@leopard.t.u-tokyo.ac.j [School of Engineering and Applied Sciences, Harvard University, 60 Oxford Street, Cambridge, MA 02138 (United States)

    2010-09-15

    This paper presents direct measurements of the aerodynamic forces on the wing of a free-flying, insect-like ornithopter that was modeled on a hawk moth (Manduca sexta). A micro differential pressure sensor was fabricated with micro electro mechanical systems (MEMS) technology and attached to the wing of the ornithopter. The sensor chip was less than 0.1% of the wing area. The mass of the sensor chip was 2.0 mg, which was less than 1% of the wing mass. Thus, the sensor was both small and light in comparison with the wing, resulting in a measurement system that had a minimal impact on the aerodynamics of the wing. With this sensor, the 'pressure coefficient' of the ornithopter wing was measured during both steady airflow and actual free flight. The maximum pressure coefficient observed for steady airflow conditions was 1.4 at an angle of attack of 30{sup 0}. In flapping flight, the coefficient was around 2.0 for angles of attack that ranged from 25{sup 0} to 40{sup 0}. Therefore, a larger aerodynamic force was generated during the downstroke in free flight compared to steady airflow conditions.

  5. A method enabling simultaneous pressure and temperature measurement using a single piezoresistive MEMS pressure sensor

    International Nuclear Information System (INIS)

    Frantlović, Miloš; Stanković, Srđan; Jokić, Ivana; Lazić, Žarko; Smiljanić, Milče; Obradov, Marko; Vukelić, Branko; Jakšić, Zoran

    2016-01-01

    In this paper we present a high-performance, simple and low-cost method for simultaneous measurement of pressure and temperature using a single piezoresistive MEMS pressure sensor. The proposed measurement method utilizes the parasitic temperature sensitivity of the sensing element for both pressure measurement correction and temperature measurement. A parametric mathematical model of the sensor was established and its parameters were calculated using the obtained characterization data. Based on the model, a real-time sensor correction for both pressure and temperature measurements was implemented in a target measurement system. The proposed method was verified experimentally on a group of typical industrial-grade piezoresistive sensors. The obtained results indicate that the method enables the pressure measurement performance to exceed that of typical digital industrial pressure transmitters, achieving at the same time the temperature measurement performance comparable to industrial-grade platinum resistance temperature sensors. The presented work is directly applicable in industrial instrumentation, where it can add temperature measurement capability to the existing pressure measurement instruments, requiring little or no additional hardware, and without adverse effects on pressure measurement performance. (paper)

  6. Novel strategies for development of gas sensors for combustion and medical applications

    Science.gov (United States)

    Fulmer, Adam; Mullen, Max; Sun, Chenhu; Dutta, Prabir K.

    2014-06-01

    Chemical gas sensors can have an enormous impact on optimizing complex processes as well as facilitate disease diagnosis. In this article, we demonstrate how sensing of gas molecules is influencing the next generation of engines for transportation applications, as well as in disease diagnosis. In such applications, the demands on sensors are quite extreme. Not only does the device have to detect the gas of interest with high sensitivity, it also has to discriminate against other species present in a complex environment, such as combustion exhaust and human breath. In addition, the sensors will need to have as small a footprint as possible in size and power requirements. With these varied requirements in mind, only electrochemical sensors have the potential to be practical. This article focuses on nitric oxide (NOx) and ammonia (NH3) sensor necessary for emission control of next generation, high efficiency, lean burn engines and nitric oxide (NO) sensor for breath analysis for diagnosis of respiratory diseases. In all of these applications, there has been significant recent commercial activity. We indicate the electrochemical principles of these commercial sensors, and the development from our research group. We present potentiometric total NOx sensors that can operate in harsh environments, and impedance-based NH3 sensor for transportation industry. For detecting NO in human breath, we have demonstrated two strategies, the first using a resistive approach, and the second with an array of potentiometric sensors. Data from these sensors, their limitations as well as novel MEMS-based approaches for miniaturization is presented.

  7. On Packaging of MEMS. Simulation of Transfer Moulding and Packaging Stress and their Effect on a Family of piezo-resistive Pressure Sensors

    OpenAIRE

    Krondorfer, Rudolf H.

    2004-01-01

    Micro Electro Mechanical Systems (MEMS) produced to date include IR detectors, accelerometers, pressure sensors, micro lenses, actuators, chemical sensors, gear drives, RF devices, optical processor chips, micro robots and devices for biomedical analysis. The track for tomorrow has already been set and products like 3D TV, physician on a chip, lab on a chip, micro aircraft and food safety sensors will be developed when the technology matures and the market is ready. Todays MEMS fabricatio...

  8. Polymer/ceramic wireless MEMS pressure sensors for harsh environments: High temperature and biomedical applications

    Science.gov (United States)

    Fonseca, Michael A.

    2007-12-01

    This dissertation presents an investigation of miniaturized sensors, designed to wirelessly measure pressure in harsh environments such as high temperature and biomedical applications. Current wireless microelectromechanical systems (MEMS) pressure sensors are silicon-based and have limited high temperature operation, require internal power sources, or have limited packaging technology that restricts their use in harsh environments. Sensor designs in this work are based on passive LC resonant circuits to achieve wireless telemetry without the need for active circuitry or internal power sources. A cavity, which is embedded into the substrate, is bound by two pressure-deformable plates that include a parallel-plate capacitor. Deflection of the plates from applied pressure changes the capacitance, thus, the resonance frequency varies and is a function of the applied pressure. The LC resonant circuit and pressure-deformable plates are fabricated into a monolithic housing that servers as the final device package (i.e. intrinsically packaged). This co-integration of device and package offers increased robustness and the ability to operate wirelessly in harsh environments. To intrinsically packaged devices, the fabrication approach relies on techniques developed for MEMS and leverage established lamination-based manufacturing processes, such as ceramic and flexible-circuit-board (flex-circuit) packaging technologies. The sensor concept is further developed by deriving the electromechanical model describing the sensor behavior. The model is initially divided into the electromagnetic model, used to develop the passive wireless telemetry, and the mechanical model, used to develop the pressure dependence of the sensor, which are then combined to estimate the sensor resonance frequency dependence as a function of applied pressure. The derived analytical model allows parametric optimization of sensor designs. The sensor concept is demonstrated in two applications: high

  9. Kalman Filters in Geotechnical Monitoring of Ground Subsidence Using Data from MEMS Sensors.

    Science.gov (United States)

    Li, Cheng; Azzam, Rafig; Fernández-Steeger, Tomás M

    2016-07-19

    The fast development of wireless sensor networks and MEMS make it possible to set up today real-time wireless geotechnical monitoring. To handle interferences and noises from the output data, Kalman filter can be selected as a method to achieve a more realistic estimate of the observations. In this paper, a one-day wireless measurement using accelerometers and inclinometers was deployed on top of a tunnel section under construction in order to monitor ground subsidence. The normal vectors of the sensors were firstly obtained with the help of rotation matrices, and then be projected to the plane of longitudinal section, by which the dip angles over time would be obtained via a trigonometric function. Finally, a centralized Kalman filter was applied to estimate the tilt angles of the sensor nodes based on the data from the embedded accelerometer and the inclinometer. Comparing the results from two sensor nodes deployed away and on the track respectively, the passing of the tunnel boring machine can be identified from unusual performances. Using this method, the ground settlement due to excavation can be measured and a real-time monitoring of ground subsidence can be realized.

  10. SoundCompass: a distributed MEMS microphone array-based sensor for sound source localization.

    Science.gov (United States)

    Tiete, Jelmer; Domínguez, Federico; da Silva, Bruno; Segers, Laurent; Steenhaut, Kris; Touhafi, Abdellah

    2014-01-23

    Sound source localization is a well-researched subject with applications ranging from localizing sniper fire in urban battlefields to cataloging wildlife in rural areas. One critical application is the localization of noise pollution sources in urban environments, due to an increasing body of evidence linking noise pollution to adverse effects on human health. Current noise mapping techniques often fail to accurately identify noise pollution sources, because they rely on the interpolation of a limited number of scattered sound sensors. Aiming to produce accurate noise pollution maps, we developed the SoundCompass, a low-cost sound sensor capable of measuring local noise levels and sound field directionality. Our first prototype is composed of a sensor array of 52 Microelectromechanical systems (MEMS) microphones, an inertial measuring unit and a low-power field-programmable gate array (FPGA). This article presents the SoundCompass's hardware and firmware design together with a data fusion technique that exploits the sensing capabilities of the SoundCompass in a wireless sensor network to localize noise pollution sources. Live tests produced a sound source localization accuracy of a few centimeters in a 25-m2 anechoic chamber, while simulation results accurately located up to five broadband sound sources in a 10,000-m2 open field.

  11. Kalman Filters in Geotechnical Monitoring of Ground Subsidence Using Data from MEMS Sensors

    Science.gov (United States)

    Li, Cheng; Azzam, Rafig; Fernández-Steeger, Tomás M.

    2016-01-01

    The fast development of wireless sensor networks and MEMS make it possible to set up today real-time wireless geotechnical monitoring. To handle interferences and noises from the output data, Kalman filter can be selected as a method to achieve a more realistic estimate of the observations. In this paper, a one-day wireless measurement using accelerometers and inclinometers was deployed on top of a tunnel section under construction in order to monitor ground subsidence. The normal vectors of the sensors were firstly obtained with the help of rotation matrices, and then be projected to the plane of longitudinal section, by which the dip angles over time would be obtained via a trigonometric function. Finally, a centralized Kalman filter was applied to estimate the tilt angles of the sensor nodes based on the data from the embedded accelerometer and the inclinometer. Comparing the results from two sensor nodes deployed away and on the track respectively, the passing of the tunnel boring machine can be identified from unusual performances. Using this method, the ground settlement due to excavation can be measured and a real-time monitoring of ground subsidence can be realized. PMID:27447630

  12. Design and Fabrication of a MEMS Flow Sensor and Its Application in Precise Liquid Dispensing

    Directory of Open Access Journals (Sweden)

    Liguo Chen

    2009-06-01

    Full Text Available A high speed MEMS flow sensor to enhance the reliability and accuracy of a liquid dispensing system is proposed. Benefitting from the sensor information feedback, the system can self-adjust the open time of the solenoid valve to accurately dispense desired volumes of reagent without any pre-calibration. First, an integrated high-speed liquid flow sensor based on the measurement of the pressure difference across a flow channel is presented. Dimensions of the micro-flow channel and two pressure sensors have been appropriately designed to meet the static and dynamic requirements of the liquid dispensing system. Experiments results show that the full scale (FS flow measurement ranges up to 80 μL/s, with a nonlinearity better than 0.51% FS. Secondly, a novel closed-loop control strategy is proposed to calculate the valve open time in each dispensing cycle, which makes the system immune to liquid viscosity, pressure fluctuation, and other sources of error. Finally, dispensing results show that the system can achieve better dispensing performance, and the coefficient of variance (CV for liquid dispensing is below 3% at 1 μL and below 4% at 100 nL.

  13. SoundCompass: A Distributed MEMS Microphone Array-Based Sensor for Sound Source Localization

    Directory of Open Access Journals (Sweden)

    Jelmer Tiete

    2014-01-01

    Full Text Available Sound source localization is a well-researched subject with applications ranging from localizing sniper fire in urban battlefields to cataloging wildlife in rural areas. One critical application is the localization of noise pollution sources in urban environments, due to an increasing body of evidence linking noise pollution to adverse effects on human health. Current noise mapping techniques often fail to accurately identify noise pollution sources, because they rely on the interpolation of a limited number of scattered sound sensors. Aiming to produce accurate noise pollution maps, we developed the SoundCompass, a low-cost sound sensor capable of measuring local noise levels and sound field directionality. Our first prototype is composed of a sensor array of 52 Microelectromechanical systems (MEMS microphones, an inertial measuring unit and a low-power field-programmable gate array (FPGA. This article presents the SoundCompass’s hardware and firmware design together with a data fusion technique that exploits the sensing capabilities of the SoundCompass in a wireless sensor network to localize noise pollution sources. Live tests produced a sound source localization accuracy of a few centimeters in a 25-m2 anechoic chamber, while simulation results accurately located up to five broadband sound sources in a 10,000-m2 open field.

  14. SoundCompass: A Distributed MEMS Microphone Array-Based Sensor for Sound Source Localization

    Science.gov (United States)

    Tiete, Jelmer; Domínguez, Federico; da Silva, Bruno; Segers, Laurent; Steenhaut, Kris; Touhafi, Abdellah

    2014-01-01

    Sound source localization is a well-researched subject with applications ranging from localizing sniper fire in urban battlefields to cataloging wildlife in rural areas. One critical application is the localization of noise pollution sources in urban environments, due to an increasing body of evidence linking noise pollution to adverse effects on human health. Current noise mapping techniques often fail to accurately identify noise pollution sources, because they rely on the interpolation of a limited number of scattered sound sensors. Aiming to produce accurate noise pollution maps, we developed the SoundCompass, a low-cost sound sensor capable of measuring local noise levels and sound field directionality. Our first prototype is composed of a sensor array of 52 Microelectromechanical systems (MEMS) microphones, an inertial measuring unit and a low-power field-programmable gate array (FPGA). This article presents the SoundCompass’s hardware and firmware design together with a data fusion technique that exploits the sensing capabilities of the SoundCompass in a wireless sensor network to localize noise pollution sources. Live tests produced a sound source localization accuracy of a few centimeters in a 25-m2 anechoic chamber, while simulation results accurately located up to five broadband sound sources in a 10,000-m2 open field. PMID:24463431

  15. Gas Composition Sensor for Natural Gas and Biogas

    NARCIS (Netherlands)

    Boersma, A.; Sweelsen, J.; Blokland, H.

    2016-01-01

    The calorific value of energetic gasses is an important parameter in the quality assessment of gas steams, and can be calculated from the chemical composition of the gas. An array of capacitive sensor electrodes was developed, each functionalized with a gas responsive coating to measure the

  16. A MEMS Resonant Sensor to Measure Fluid Density and Viscosity under Flexural and Torsional Vibrating Modes

    Directory of Open Access Journals (Sweden)

    Libo Zhao

    2016-06-01

    Full Text Available Methods to calculate fluid density and viscosity using a micro-cantilever and based on the resonance principle were put forward. Their measuring mechanisms were analyzed and the theoretical equations to calculate the density and viscosity were deduced. The fluid-solid coupling simulations were completed for the micro-cantilevers with different shapes. The sensing chips with micro-cantilevers were designed based on the simulation results and fabricated using the micro electromechanical systems (MEMS technology. Finally, the MEMS resonant sensor was packaged with the sensing chip to measure the densities and viscosities of eight different fluids under the flexural and torsional vibrating modes separately. The relative errors of the measured densities from 600 kg/m3 to 900 kg/m3 and viscosities from 200 μPa·s to 1000 μPa·s were calculated and analyzed with different microcantilevers under various vibrating modes. The experimental results showed that the effects of the shape and vibrating mode of micro-cantilever on the measurement accuracies of fluid density and viscosity were analyzed in detail.

  17. A MEMS Resonant Sensor to Measure Fluid Density and Viscosity under Flexural and Torsional Vibrating Modes.

    Science.gov (United States)

    Zhao, Libo; Hu, Yingjie; Wang, Tongdong; Ding, Jianjun; Liu, Xixiang; Zhao, Yulong; Jiang, Zhuangde

    2016-06-06

    Methods to calculate fluid density and viscosity using a micro-cantilever and based on the resonance principle were put forward. Their measuring mechanisms were analyzed and the theoretical equations to calculate the density and viscosity were deduced. The fluid-solid coupling simulations were completed for the micro-cantilevers with different shapes. The sensing chips with micro-cantilevers were designed based on the simulation results and fabricated using the micro electromechanical systems (MEMS) technology. Finally, the MEMS resonant sensor was packaged with the sensing chip to measure the densities and viscosities of eight different fluids under the flexural and torsional vibrating modes separately. The relative errors of the measured densities from 600 kg/m³ to 900 kg/m³ and viscosities from 200 μPa·s to 1000 μPa·s were calculated and analyzed with different microcantilevers under various vibrating modes. The experimental results showed that the effects of the shape and vibrating mode of micro-cantilever on the measurement accuracies of fluid density and viscosity were analyzed in detail.

  18. Characterization of Polymeric Chemiresistors for Gas Sensor

    Directory of Open Access Journals (Sweden)

    Hendro Juwono

    2012-06-01

    Full Text Available Composite polymer-carbon has resistance change if come into contact with gas. Composite polymer-carbon can be used as a gas sensor. This research will be characterized the sensor composite polymer-carbon that has been made from 6 types of polymer, which are; PEG6000, PEG20M, PEG200, PEG1540, Silicon and Squelene. The 6 sensors will be tested by 9 types of gas, which are; Aceton, Aceton Nitril, Benzene, Etanol, Methanol, Ethyl Aceton, Chloroform, n-Hexan and Toluene. This characterization will be grouped into 4 claster of characteristics, which are; the selectivity (influence type of gas, the sensitivity (influence volume of gas, the influence of temperature and the influence of humidity. Test using method testing sensors that paleced in an isolated chamber which is connected with data acquisition. variations of temperature, humidity, type and volume of gas will be condition in the chamber. Correspondence analysis and regression will be used to process the data. Test results found that each sensor of type of polymers have different sensitivity and selectivity towards a particular type of gas. Resistance sensors increases with rising temperature and humidity environment with a polynomial equation of order-2 and order-3

  19. Airborne Multi-Gas Sensor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Mesa Photonics proposes to develop an Airborne Multi-Gas Sensor (AMUGS) based upon two-tone, frequency modulation spectroscopy (TT-FMS). Mesa Photonics has developed...

  20. Electric Power Self-Supply Module for WSN Sensor Node Based on MEMS Vibration Energy Harvester

    Directory of Open Access Journals (Sweden)

    Wenyang Zhang

    2018-04-01

    Full Text Available This paper proposes an electric power self-supply module for the wireless sensor network (WSN sensor node. The module includes an electromagnetic vibration energy harvester based on micro-electro-mechanical system (MEMS technology and a processing circuit. The vibration energy harvester presented in this paper is fabricated by an integrated microfabrication process and consists of four similar and relatively independent beam vibration elements. The main functions of the processing circuit are to convert the output of the harvester from unstable alternating current (AC to stable direct current (DC, charge the super capacitor, and ensure the stable output of the super capacitor. The preliminary test results of the harvester chip show that the chip can output discontinuous pulse voltage, and the range of the voltage value is from tens to hundreds of millivolts in the vibration frequency range of 10–90 Hz. The maximum value that can be reached is 563 mV (at the vibration frequency of 18 Hz. The results of the test show that the harvester can output a relatively high voltage, which can meet the general electric power demand of a WSN sensor node.

  1. MEMS fiber-optic Fabry-Perot pressure sensor for high temperature application

    Science.gov (United States)

    Fang, G. C.; Jia, P. G.; Cao, Q.; Xiong, J. J.

    2016-10-01

    We design and demonstrate a fiber-optic Fabry-Perot pressure sensor (FOFPPS) for high-temperature sensing by employing micro-electro-mechanical system (MEMS) technology. The FOFPPS is fabricated by anodically bonding the silicon wafer and the Pyrex glass together and fixing the facet of the optical fiber in parallel with the silicon surface by glass frit and organic adhesive. The silicon wafer can be reduced through dry etching technology to construct the sensitive diaphragm. The length of the cavity changes with the deformation of the diaphragm due to the loaded pressure, which leads to a wavelength shift of the interference spectrum. The pressure can be gauged by measuring the wavelength shift. The pressure experimental results show that the sensor has linear pressure sensitivities ranging from 0 kPa to 600 kPa at temperature range between 20°C to 300°C. The pressure sensitivity at 300°C is approximately 27.63 pm/kPa. The pressure sensitivities gradually decrease with increasing the temperature. The sensor also has a linear thermal drift when temperature changes from 20°C - 300°C.

  2. Cupula-Inspired Hyaluronic Acid-Based Hydrogel Encapsulation to Form Biomimetic MEMS Flow Sensors.

    Science.gov (United States)

    Kottapalli, Ajay Giri Prakash; Bora, Meghali; Kanhere, Elgar; Asadnia, Mohsen; Miao, Jianmin; Triantafyllou, Michael S

    2017-07-28

    Blind cavefishes are known to detect objects through hydrodynamic vision enabled by arrays of biological flow sensors called neuromasts. This work demonstrates the development of a MEMS artificial neuromast sensor that features a 3D polymer hair cell that extends into the ambient flow. The hair cell is monolithically fabricated at the center of a 2 μm thick silicon membrane that is photo-patterned with a full-bridge bias circuit. Ambient flow variations exert a drag force on the hair cell, which causes a displacement of the sensing membrane. This in turn leads to the resistance imbalance in the bridge circuit generating a voltage output. Inspired by the biological neuromast, a biomimetic synthetic hydrogel cupula is incorporated on the hair cell. The morphology, swelling behavior, porosity and mechanical properties of the hyaluronic acid hydrogel are characterized through rheology and nanoindentation techniques. The sensitivity enhancement in the sensor output due to the material and mechanical contributions of the micro-porous hydrogel cupula is investigated through experiments.

  3. PREFACE: 1st European Conference on Gas Micro Flows (GasMems 2012)

    Science.gov (United States)

    Frijns, Arjan; Valougeorgis, Dimitris; Colin, Stéphane; Baldas, Lucien

    2012-05-01

    The aim of the 1st European Conference on Gas Micro Flows is to advance research in Europe and worldwide in the field of gas micro flows as well as to improve global fundamental knowledge and to enable technological applications. Gas flows in microsystems are of great importance and touch almost every industrial field (e.g. fluidic microactuators for active control of aerodynamic flows, vacuum generators for extracting biological samples, mass flow and temperature micro-sensors, pressure gauges, micro heat-exchangers for the cooling of electronic components or for chemical applications, and micro gas analyzers or separators). The main characteristic of gas microflows is their rarefaction, which for device design often requires modelling and simulation both by continuous and molecular approaches. In such flows various non-equilibrium transport phenomena appear, while the role played by the interaction between the gas and the solid device surfaces becomes essential. The proposed models of boundary conditions often need an empirical adjustment strongly dependent on the micro manufacturing technique. The 1st European Conference on Gas Micro Flows is organized under the umbrella of the recently established GASMEMS network (www.gasmems.eu/) consisting of 13 participants and six associate members. The main objectives of the network are to structure research and train researchers in the fields of micro gas dynamics, measurement techniques for gaseous flows in micro experimental setups, microstructure design and micro manufacturing with applications in lab and industry. The conference takes place on June 6-8 2012, at the Skiathos Palace Hotel, on the beautiful island of Skiathos, Greece. The conference has received funding from the European Community's Seventh Framework Programme FP7/2007-2013 under grant agreement ITN GASMEMS no. 215504. It owes its success to many people. We would like to acknowledge the support of all members of the Scientific Committee and of all

  4. MEMS pressure sensor with maximum performances by using novel back-side direct-exposure concept featuring through glass vias

    Science.gov (United States)

    Mukhopadhyay, B.; Fritz, M.; Mackowiak, P.; Vu, T. C.; Ehrmann, O.; Lang, K.-D.; Ngo, H.-D.

    2013-05-01

    Design, simulation, fabrication, and characterization of novel MEMS pressure sensors with new back-side-direct-exposure packaging concept are presented. The sensor design is optimized for harsh environments e.g. space, military, offshore and medical applications. Unbreakable connection between the active side of the Si-sensor and the protecting glass capping was realized by anodic bonding using a thin layer of metal. To avoid signal corruption of the measured pressure caused by an encapsulation system, the media has direct contact to the backside of the Si membrane and can deflect it.

  5. Gas Sensors Based on Electrodeposited Polymers

    Directory of Open Access Journals (Sweden)

    Boris Lakard

    2015-07-01

    Full Text Available Electrochemically deposited polymers, also called “synthetic metals”, have emerged as potential candidates for chemical sensing due to their interesting and tunable chemical, electrical, and structural properties. In particular, most of these polymers (including polypyrrole, polyaniline, polythiophene and their derivatives can be used as the sensitive layer of conductimetric gas sensors because of their conducting properties. An important advantage of polymer-based gas sensors is their efficiency at room temperature. This characteristic is interesting since most of the commercially-available sensors, usually based on metal oxides, work at high temperatures (300–400 °C. Consequently, polymer-based gas sensors are playing a growing role in the improvement of public health and environment control because they can lead to gas sensors operating with rapid detection, high sensitivity, small size, and specificity in atmospheric conditions. In this review, the recent advances in electrodeposited polymer-based gas sensors are summarized and discussed. It is shown that the sensing characteristics of electrodeposited polymers can be improved by chemical functionalization, nanostructuration, or mixing with other functional materials to form composites or hybrid materials.

  6. Implementation and Performance of a GPS/INS Tightly Coupled Assisted PLL Architecture Using MEMS Inertial Sensors

    Directory of Open Access Journals (Sweden)

    Youssef Tawk

    2014-02-01

    Full Text Available The use of global navigation satellite system receivers for navigation still presents many challenges in urban canyon and indoor environments, where satellite availability is typically reduced and received signals are attenuated. To improve the navigation performance in such environments, several enhancement methods can be implemented. For instance, external aid provided through coupling with other sensors has proven to contribute substantially to enhancing navigation performance and robustness. Within this context, coupling a very simple GPS receiver with an Inertial Navigation System (INS based on low-cost micro-electro-mechanical systems (MEMS inertial sensors is considered in this paper. In particular, we propose a GPS/INS Tightly Coupled Assisted PLL (TCAPLL architecture, and present most of the associated challenges that need to be addressed when dealing with very-low-performance MEMS inertial sensors. In addition, we propose a data monitoring system in charge of checking the quality of the measurement flow in the architecture. The implementation of the TCAPLL is discussed in detail, and its performance under different scenarios is assessed. Finally, the architecture is evaluated through a test campaign using a vehicle that is driven in urban environments, with the purpose of highlighting the pros and cons of combining MEMS inertial sensors with GPS over GPS alone.

  7. On the design of a MEMS piezoelectric accelerometer coupled to the middle ear as an implantable sensor for hearing devices.

    Science.gov (United States)

    Gesing, A L; Alves, F D P; Paul, S; Cordioli, J A

    2018-03-02

    The presence of external elements is a major limitation of current hearing aids and cochlear implants, as they lead to discomfort and inconvenience. Totally implantable hearing devices have been proposed as a solution to mitigate these constraints, which has led to challenges in designing implantable sensors. This work presents a feasibility analysis of a MEMS piezoelectric accelerometer coupled to the ossicular chain as an alternative sensor. The main requirements of the sensor include small size, low internal noise, low power consumption, and large bandwidth. Different designs of MEMS piezoelectric accelerometers were modeled using Finite Element (FE) method, as well as optimized for high net charge sensitivity. The best design, a 2 × 2 mm 2 annular configuration with a 500 nm thick Aluminum Nitride (AlN) layer was selected for fabrication. The prototype was characterized, and its charge sensitivity and spectral acceleration noise were found to be with good agreement to the FE model predictions. Weak coupling between a middle ear FE model and the prototype was considered, resulting in equivalent input noise (EIN) lower than 60 dB sound pressure level between 600 Hz and 10 kHz. These results are an encouraging proof of concept for the development of MEMS piezoelectric accelerometers as implantable sensors for hearing devices.

  8. Error and Performance Analysis of MEMS-based Inertial Sensors with a Low-cost GPS Receiver

    Directory of Open Access Journals (Sweden)

    Yang Gao

    2008-03-01

    Full Text Available Global Navigation Satellite Systems (GNSS, such as the Global Positioning System (GPS, have been widely utilized and their applications are becoming popular, not only in military or commercial applications, but also for everyday life. Although GPS measurements are the essential information for currently developed land vehicle navigation systems (LVNS, GPS signals are often unavailable or unreliable due to signal blockages under certain environments such as urban canyons. This situation must be compensated in order to provide continuous navigation solutions. To overcome the problems of unavailability and unreliability using GPS and to be cost and size effective as well, Micro Electro Mechanical Systems (MEMS based inertial sensor technology has been pushing for the development of low-cost integrated navigation systems for land vehicle navigation and guidance applications. This paper will analyze the characterization of MEMS based inertial sensors and the performance of an integrated system prototype of MEMS based inertial sensors, a low-cost GPS receiver and a digital compass. The influence of the stochastic variation of sensors will be assessed and modeled by two different methods, namely Gauss-Markov (GM and AutoRegressive (AR models, with GPS signal blockage of different lengths. Numerical results from kinematic testing have been used to assess the performance of different modeling schemes.

  9. A Rapid Process for Fabricating Gas Sensors

    Directory of Open Access Journals (Sweden)

    Chun-Ching Hsiao

    2014-07-01

    Full Text Available Zinc oxide (ZnO is a low-toxicity and environmentally-friendly material applied on devices, sensors or actuators for “green” usage. A porous ZnO film deposited by a rapid process of aerosol deposition (AD was employed as the gas-sensitive material in a CO gas sensor to reduce both manufacturing cost and time, and to further extend the AD application for a large-scale production. The relative resistance change (△R/R of the ZnO gas sensor was used for gas measurement. The fabricated ZnO gas sensors were measured with operating temperatures ranging from 110 °C to 180 °C, and CO concentrations ranging from 100 ppm to 1000 ppm. The sensitivity and the response time presented good performance at increasing operating temperatures and CO concentrations. AD was successfully for applied for making ZnO gas sensors with great potential for achieving high deposition rates at low deposition temperatures, large-scale production and low cost.

  10. Electrochemical impedance spectroscopy based MEMS sensors for phthalates detection in water and juices

    Science.gov (United States)

    Zia, Asif I.; Mohd Syaifudin, A. R.; Mukhopadhyay, S. C.; Yu, P. L.; Al-Bahadly, I. H.; Gooneratne, Chinthaka P.; Kosel, Jǘrgen; Liao, Tai-Shan

    2013-06-01

    Phthalate esters are ubiquitous environmental and food pollutants well known as endocrine disrupting compounds (EDCs). These developmental and reproductive toxicants pose a grave risk to the human health due to their unlimited use in consumer plastic industry. Detection of phthalates is strictly laboratory based time consuming and expensive process and requires expertise of highly qualified and skilled professionals. We present a real time, non-invasive, label free rapid detection technique to quantify phthalates' presence in deionized water and fruit juices. Electrochemical impedance spectroscopy (EIS) technique applied to a novel planar inter-digital (ID) capacitive sensor plays a vital role to explore the presence of phthalate esters in bulk fluid media. The ID sensor with multiple sensing gold electrodes was fabricated on silicon substrate using micro-electromechanical system (MEMS) device fabrication technology. A thin film of parylene C polymer was coated as a passivation layer to enhance the capacitive sensing capabilities of the sensor and to reduce the magnitude of Faradic current flowing through the sensor. Various concentrations, 0.002ppm through to 2ppm of di (2-ethylhexyl) phthalate (DEHP) in deionized water, were exposed to the sensing system by dip testing method. Impedance spectra obtained was analysed to determine sample conductance which led to consequent evaluation of its dielectric properties. Electro-chemical impedance spectrum analyser algorithm was employed to model the experimentally obtained impedance spectra. Curve fitting technique was applied to deduce constant phase element (CPE) equivalent circuit based on Randle's equivalent circuit model. The sensing system was tested to detect different concentrations of DEHP in orange juice as a real world application. The result analysis indicated that our rapid testing technique is able to detect the presence of DEHP in all test samples distinctively.

  11. A Wireless MEMS-Based Inclinometer Sensor Node for Structural Health Monitoring

    Science.gov (United States)

    Ha, Dae Woong; Park, Hyo Seon; Choi, Se Woon; Kim, Yousok

    2013-01-01

    This paper proposes a wireless inclinometer sensor node for structural health monitoring (SHM) that can be applied to civil engineering and building structures subjected to various loadings. The inclinometer used in this study employs a method for calculating the tilt based on the difference between the static acceleration and the acceleration due to gravity, using a micro-electro-mechanical system (MEMS)-based accelerometer. A wireless sensor node was developed through which tilt measurement data are wirelessly transmitted to a monitoring server. This node consists of a slave node that uses a short-distance wireless communication system (RF 2.4 GHz) and a master node that uses a long-distance telecommunication system (code division multiple access—CDMA). The communication distance limitation, which is recognized as an important issue in wireless monitoring systems, has been resolved via these two wireless communication components. The reliability of the proposed wireless inclinometer sensor node was verified experimentally by comparing the values measured by the inclinometer and subsequently transferred to the monitoring server via wired and wireless transfer methods to permit a performance evaluation of the wireless communication sensor nodes. The experimental results indicated that the two systems (wired and wireless transfer systems) yielded almost identical values at a tilt angle greater than 1°, and a uniform difference was observed at a tilt angle less than 0.42° (approximately 0.0032° corresponding to 0.76% of the tilt angle, 0.42°) regardless of the tilt size. This result was deemed to be within the allowable range of measurement error in SHM. Thus, the wireless transfer system proposed in this study was experimentally verified for practical application in a structural health monitoring system. PMID:24287533

  12. Electrochemical impedance spectroscopy based MEMS sensors for phthalates detection in water and juices

    International Nuclear Information System (INIS)

    Zia, Asif I; Syaifudin, A R Mohd; Mukhopadhyay, S C; Yu, P L; Al-Bahadly, I H; Gooneratne, Chinthaka P; Kosel, Juergen; Liao, Tai-Shan

    2013-01-01

    Phthalate esters are ubiquitous environmental and food pollutants well known as endocrine disrupting compounds (EDCs). These developmental and reproductive toxicants pose a grave risk to the human health due to their unlimited use in consumer plastic industry. Detection of phthalates is strictly laboratory based time consuming and expensive process and requires expertise of highly qualified and skilled professionals. We present a real time, non-invasive, label free rapid detection technique to quantify phthalates' presence in deionized water and fruit juices. Electrochemical impedance spectroscopy (EIS) technique applied to a novel planar inter-digital (ID) capacitive sensor plays a vital role to explore the presence of phthalate esters in bulk fluid media. The ID sensor with multiple sensing gold electrodes was fabricated on silicon substrate using micro-electromechanical system (MEMS) device fabrication technology. A thin film of parylene C polymer was coated as a passivation layer to enhance the capacitive sensing capabilities of the sensor and to reduce the magnitude of Faradic current flowing through the sensor. Various concentrations, 0.002ppm through to 2ppm of di (2-ethylhexyl) phthalate (DEHP) in deionized water, were exposed to the sensing system by dip testing method. Impedance spectra obtained was analysed to determine sample conductance which led to consequent evaluation of its dielectric properties. Electro-chemical impedance spectrum analyser algorithm was employed to model the experimentally obtained impedance spectra. Curve fitting technique was applied to deduce constant phase element (CPE) equivalent circuit based on Randle's equivalent circuit model. The sensing system was tested to detect different concentrations of DEHP in orange juice as a real world application. The result analysis indicated that our rapid testing technique is able to detect the presence of DEHP in all test samples distinctively.

  13. Electrochemical impedance spectroscopy based MEMS sensors for phthalates detection in water and juices

    KAUST Repository

    Zia, Asif I

    2013-06-10

    Phthalate esters are ubiquitous environmental and food pollutants well known as endocrine disrupting compounds (EDCs). These developmental and reproductive toxicants pose a grave risk to the human health due to their unlimited use in consumer plastic industry. Detection of phthalates is strictly laboratory based time consuming and expensive process and requires expertise of highly qualified and skilled professionals. We present a real time, non-invasive, label free rapid detection technique to quantify phthalates\\' presence in deionized water and fruit juices. Electrochemical impedance spectroscopy (EIS) technique applied to a novel planar inter-digital (ID) capacitive sensor plays a vital role to explore the presence of phthalate esters in bulk fluid media. The ID sensor with multiple sensing gold electrodes was fabricated on silicon substrate using micro-electromechanical system (MEMS) device fabrication technology. A thin film of parylene C polymer was coated as a passivation layer to enhance the capacitive sensing capabilities of the sensor and to reduce the magnitude of Faradic current flowing through the sensor. Various concentrations, 0.002ppm through to 2ppm of di (2-ethylhexyl) phthalate (DEHP) in deionized water, were exposed to the sensing system by dip testing method. Impedance spectra obtained was analysed to determine sample conductance which led to consequent evaluation of its dielectric properties. Electro-chemical impedance spectrum analyser algorithm was employed to model the experimentally obtained impedance spectra. Curve fitting technique was applied to deduce constant phase element (CPE) equivalent circuit based on Randle\\'s equivalent circuit model. The sensing system was tested to detect different concentrations of DEHP in orange juice as a real world application. The result analysis indicated that our rapid testing technique is able to detect the presence of DEHP in all test samples distinctively.

  14. Concept for a MEMS-type vacuum sensor based on electrical conductivity measurements

    Directory of Open Access Journals (Sweden)

    F. J. Giebel

    2017-11-01

    Full Text Available The concept of the micro-structured vacuum sensor presented in this article is the measurement of the electrical conductivity of thinned gases in order to develop a small, economical and quite a simple type of vacuum sensor. There are already some approaches for small vacuum sensors. Most of them are based on conservative measurement principles similar to those used in macroscopic vacuum gauges. Ionization gauges use additional sources of energy, like hot cathodes, ultraviolet radiation or high voltage for example, for ionizing gas molecules and thereby increasing the number of charge carriers for measuring low pressures. In contrast, the concept discussed here cannot be found in macroscopic sensor systems because it depends on the microscopic dimension of a gas volume defined by two electrodes. Here we present the concept and the production of a micro-structured vacuum sensor chip, followed by the electrical characterization. Reference measurements with electrodes at a distance of about 1 mm showed currents in the size of picoampere and a conductivity depending on ambient pressure. In comparison with these preliminary measurements, fundamental differences regarding pressure dependence of the conductivity are monitored in the electrical characterization of the micro-structured sensor chip. Finally the future perspectives of this sensor concept are discussed.

  15. A high thermal resistance MEMS-based Pirani vacuum sensor chip

    Science.gov (United States)

    Dams, Florian; Schreiner, Rupert

    2013-05-01

    The performance of thermal conductivity vacuum gauges can be improved by a well-designed geometry. The lower measurement range limit is determined by the size of the active sensing area and the thermal conduction heat losses through the supporting structures. The upper measurement range is limited by the distance between the heated element and the cold reference plane. Silicon based MEMS-technology gives the possibility to fabricate both sensing structures with suitable areas out of low thermal conductive materials and narrow gaps in order to extend the measurement range in both directions. In this work we present a MEMS-process to fabricate high thermal resistance sensor structures. The rectangular sensitive areas are anchored by four beams and are structured out of low thermal conductive PECVD-siliconnitride films with 1 µm in thickness. The metallic heating structure is completely embedded in the SiN-layer. Both sensitive area and its support beams were released from the silicon bulk material by anisotropic underetching. In this way a free-supporting structure with a gap of 150 μm to the silicon substrate was formed. The influence of the filament geometry and temperature was systematically investigated to determine the properties of the chips as thermal conductivity vacuum gauges. The temperature of the sensitive area was held constant by a self-balancing bridge circuit and the heating power was measured by a Δ-Σ-ADC. The average solid state thermal conductivity is in the order of 106WK1. The measuring range of the most sensitive structures covers 8 orders of magnitude from 105 mbar to 1000mbar.

  16. MEMS Technology Sensors as a More Advantageous Technique for Measuring Foot Plantar Pressure and Balance in Humans

    Directory of Open Access Journals (Sweden)

    Clara Sanz Morère

    2016-01-01

    Full Text Available Locomotor activities are part and parcel of daily human life. During walking or running, feet are subjected to high plantar pressure, leading sometimes to limb problems, pain, or foot ulceration. A current objective in foot plantar pressure measurements is developing sensors that are small in size, lightweight, and energy efficient, while enabling high mobility, particularly for wearable applications. Moreover, improvements in spatial resolution, accuracy, and sensitivity are of interest. Sensors with improved sensing techniques can be applied to a variety of research problems: diagnosing limb problems, footwear design, or injury prevention. This paper reviews commercially available sensors used in foot plantar pressure measurements and proposes the utilization of pressure sensors based on the MEMS (microelectromechanical systems technique. Pressure sensors based on this technique have the capacity to measure pressure with high accuracy and linearity up to high pressure levels. Moreover, being small in size, they are highly suitable for this type of measurement. We present two MEMS sensor models and study their suitability for the intended purpose by performing several experiments. Preliminary results indicate that the sensors are indeed suitable for measuring foot plantar pressure. Importantly, by measuring pressure continuously, they can also be utilized for body balance measurements.

  17. A Pedestrian Dead Reckoning System Integrating Low-Cost MEMS Inertial Sensors and GPS Receiver

    Directory of Open Access Journals (Sweden)

    Jin-feng Li

    2014-04-01

    Full Text Available The body-mounted inertial systems for pedestrian navigation do not require any preinstalled facilities and can run autonomously. The advantages over other technologies make it especially attractive for the applications such as first responders, military and consumer markets. The hardware platform integrating the low-cost, low-power and small-size MEMS (micro-electro-mechanical systems inertial sensors and GPS (global positioning system receiver is proposed. When the satellite signals are available, the location of the pedestrian is directly obtained from the GPS receiver. The inertial sensors are the complement of the GPS receiver in places where the GPS signals are not available, such as indoors, urban canyons and places under dense foliages. The height tracking is achieved by the barometer. The proposed PDR (pedestrian dead reckoning algorithm is real-timely implemented in the platform. The simple but effective step detection and step length estimation method are realized to reduce the computation and memory requirements on the microprocessor. A complementary filter is proposed to fuse the data from the accelerometer, gyroscope and digital compass for decreasing the heading error, which is the main error source in positioning. The reliability and accuracy of the proposed system is verified by field pedestrian walking tests in outdoors and indoors. The positioning error is less than 4% of the total traveled distance. The results indicate that the pedestrian dead reckoning system is able to provide satisfactory tracking performance.

  18. Development of a MEMS dual-axis differential capacitance floating element shear stress sensor

    Energy Technology Data Exchange (ETDEWEB)

    Barnard, Casey [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Griffin, Benjamin [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    A single-axis MEMS wall shear stress sensor with differential capacitive transduction method is produced. Using a synchronous modulation and demodulation interface circuit, the system is capable of making real time measurements of both mean and fluctuating wall shear stress. A sensitivity of 3.44 mV/Pa is achieved, with linearity in response demonstrated up to testing limit of 2 Pa. Minimum detectable signals of 340 μPa at 100 Hz and 120 μPa at 1 kHz are indicated, with a resonance of 3.5 kHz. Multiple full scale wind tunnel tests are performed, producing spectral measurements of turbulent boundary layers in wind speeds ranging up to 0.5 Ma (18 Pa of mean wall shear stress). The compact packaging allows for minimally invasive installation, and has proven relatively robust over multiple testing events. Temperature sensitivity, likely due to poor CTE matching of packaged materials, is an ongoing concern being addressed. These successes are being directly leveraged into a development plan for a dual-axis wall shear stress sensor, capable of producing true vector estimates at the wall.

  19. Gas Sensors Based on Ceramic p-n Heterocontacts

    Energy Technology Data Exchange (ETDEWEB)

    Aygun, Seymen Murat [Iowa State Univ., Ames, IA (United States)

    2005-01-01

    with very high forward currents. Ga doped heterocontacts showed the highest sensitivity observed during current-time measurements as well, even though the sensor response was rather slow. Finally, a possible synergistic effect of doping both p and n-sides was studied by utilizing current-time measurements for 1.5 mol% Ni-CuO/1.5 mol% Ga-ZnO heterocontact. A sensitivity value of ~5.1 was obtained with the fastest response among all the samples. The time needed to reach 90% coverage was lowered by a factor of 4 when compared to the pure heterocontact and the time needed to reach 70% coverage was just over one minute. Heterocontact gas sensors are promising candidates for high temperature sensor applications. Today, Si-based microelectromechanical system (MEMS) technology has shown great promise for developing novel devices such as pressure sensors, chemical sensors, and temperature sensors through complex designs. However, the harsh thermal, vibrational, and corrosive environments common to many aerospace applications impose severe limitations on their use. Sensors based on ceramic p-n heterocontacts are promising alternatives because of their inherent corrosion resistance and environmental stability. The other advantages include their inherent tuning ability to differentiate between different reducing gases and a possible cost efficient production of a wireless sensor. Being a capacitive type sensor, its output can be transformed into a passive wireless device by creating a tuned LC circuit. In this way, the sensor output (the capacitance) can be accessed remotely by measuring the resonant frequency. The relatively simple structure of heterocontacts makes it suitable for thick film fabrication techniques to make sensor packages.

  20. Gas Sensors Based on Molecular Imprinting Technology.

    Science.gov (United States)

    Zhang, Yumin; Zhang, Jin; Liu, Qingju

    2017-07-04

    Molecular imprinting technology (MIT); often described as a method of designing a material to remember a target molecular structure (template); is a technique for the creation of molecularly imprinted polymers (MIPs) with custom-made binding sites complementary to the target molecules in shape; size and functional groups. MIT has been successfully applied to analyze; separate and detect macromolecular organic compounds. Furthermore; it has been increasingly applied in assays of biological macromolecules. Owing to its unique features of structure specificity; predictability; recognition and universal application; there has been exploration of the possible application of MIPs in the field of highly selective gas sensors. In this present study; we outline the recent advances in gas sensors based on MIT; classify and introduce the existing molecularly imprinted gas sensors; summarize their advantages and disadvantages; and analyze further research directions.

  1. Porous Silicon Structures as Optical Gas Sensors

    Directory of Open Access Journals (Sweden)

    Igor A. Levitsky

    2015-08-01

    Full Text Available We present a short review of recent progress in the field of optical gas sensors based on porous silicon (PSi and PSi composites, which are separate from PSi optochemical and biological sensors for a liquid medium. Different periodical and nonperiodical PSi photonic structures (bares, modified by functional groups or infiltrated with sensory polymers are described for gas sensing with an emphasis on the device specificity, sensitivity and stability to the environment. Special attention is paid to multiparametric sensing and sensor array platforms as effective trends for the improvement of analyte classification and quantification. Mechanisms of gas physical and chemical sorption inside PSi mesopores and pores of PSi functional composites are discussed.

  2. A bubble-based microfluidic gas sensor for gas chromatographs.

    Science.gov (United States)

    Bulbul, Ashrafuzzaman; Kim, Hanseup

    2015-01-07

    We report a new proof-of-concept bubble-based gas sensor for a gas chromatography system, which utilizes the unique relationship between the diameters of the produced bubbles with the gas types and mixture ratios as a sensing element. The bubble-based gas sensor consists of gas and liquid channels as well as a nozzle to produce gas bubbles through a micro-structure. It utilizes custom-developed software and an optical camera to statistically analyze the diameters of the produced bubbles in flow. The fabricated gas sensor showed that five types of gases (CO2, He, H2, N2, and CH4) produced (1) unique volumes of 0.44, 0.74, 1.03, 1.28, and 1.42 nL (0%, 68%, 134%, 191%, and 223% higher than that of CO2) and (2) characteristic linear expansion coefficients (slope) of 1.38, 2.93, 3.45, 5.06, and 5.44 nL/(kPa (μL s(-1))(-1)). The gas sensor also demonstrated that (3) different gas mixture ratios of CO2 : N2 (100 : 0, 80 : 20, 50 : 50, 20 : 80 and 0 : 100) generated characteristic bubble diameters of 48.95, 77.99, 71.00, 78.53 and 99.50 μm, resulting in a linear coefficient of 10.26 μm (μL s(-1))(-1). It (4) successfully identified an injection (0.01 μL) of pentane (C5) into a continuous carrier gas stream of helium (He) by monitoring bubble diameters and creating a chromatogram and demonstrated (5) the output stability within only 5.60% variation in 67 tests over a month.

  3. MEMS Inertial Sensors-Based Multi-Loop Control Enhanced by Disturbance Observation and Compensation for Fast Steering Mirror System.

    Science.gov (United States)

    Deng, Chao; Mao, Yao; Ren, Ge

    2016-11-15

    In this paper, an approach to improve the disturbance suppression performance of a fast steering mirror (FSM) tracking control system based on a charge-coupled device (CCD) and micro-electro-mechanical system (MEMS) inertial sensors is proposed. The disturbance observation and compensation (DOC) control method is recommended to enhance the classical multi-loop feedback control (MFC) for line-of-sight (LOS) stabilization in the FSM system. MEMS accelerometers and gyroscopes have been used in the FSM system tentatively to implement MFC instead of fiber-optic gyroscopes (FOG) because of its smaller, lighter, cheaper features and gradually improved performance. However, the stabilization performance of FSM is still suffering a large number of mechanical resonances and time delay induced by a low CCD sampling rate, which causes insufficient error attenuation when suffering uncertain disturbances. Thus, in order to make further improvements on the stabilization performance, a cascaded MFC enhanced by DOC method is proposed. The sensitivity of this method shows the significant improvement of the conventional MFC system. Simultaneously, the analysis of stabilization accuracy is also presented. A series of comparative experimental results demonstrate the disturbance suppression performance of the FSM control system based on the MEMS inertial sensors can be effectively improved by the proposed approach.

  4. ProTEK PSB as Biotechnology Photosensitive Protection Mask on 3C-SiC-on-Si in MEMS Sensor

    Science.gov (United States)

    Marsi, N.; Majlis, B. Y.; Mohd-Yasin, F.; Hamzah, A. A.; Mohd Rus, A. Z.

    2016-11-01

    This project presents the fabrication of MEMS employing a cubic silicon carbide (3C- SiC) on silicon wafer using newly developed ProTEK PSB as biotechnology photosensitive protection mask. This new biotechnology can reduce the number of processes and simplify the process flow with minimal impact on overall undercut performance. The 680 pm thick wafer is back-etched, leaving the 3C-SiC thin film with a thickness of 1.0 μm as the flexible diaphragm to detect pressure. The effect of the new coating of ProTEK PSB on different KOH solvents were investigated depending on various factors such as development time, final cure temperature and the thickness of the ProTEK PSB deposited layer. It is found that 6.174 μm thickness of ProTEK PSB offers some possibility of reducing the processing time compared to silicon nitride etch masks in KOH (55%wt, 80°C). The new ProTEK PSB biotechnology photosensitive protection mask indicates good stability and sustains its performance in different treatments under KOH and IPA for 8 hours. This work also revealed that the fabrication of MEMS sensors using the new biotechnology photosensitive protection mask provides a simple assembly approach and reduces manufacturing costs. The MEMS sensor can operate up to 500 °C as indicated under the sensitivity of 0.826 pF/MPa with nonlinearity and hysteresis of 0.61% and 3.13%, respectively.

  5. MAPLE activities and applications in gas sensors

    Czech Academy of Sciences Publication Activity Database

    Jelínek, Miroslav; Remsa, Jan; Kocourek, Tomáš; Kubešová, B.; Schůrek, J.; Myslík, V.

    2011-01-01

    Roč. 105, č. 3 (2011), 643-649 ISSN 0947-8396 Institutional research plan: CEZ:AV0Z10100522 Keywords : MAPLE * gas sensors * biomedicine * thin films Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.630, year: 2011

  6. Thin films for gas sensors

    Science.gov (United States)

    Pires, Jose Miguel Alves Correia

    Nos ultimos anos tem-se assistido a um aumento dos investimentos na investigacao de novos materiais para aplicacao em sensores. Apesar de ja existir um bom numero de dispositivos explorados comercialmente, muitas vezes, quer devido aos elevados custos de producao, quer devido a uma crescente exigencia do ponto de vista das caracteristicas de funcionamento, continua a ser necessario procurar novos materiais ou novas formas de producao que permitam baixar os custos e melhorar o desempenho dos dispositivos. No campo dos sensores de gases tem-se verificado continuos avancos nos ultimos anos. Continua todavia a ser necessario conhecer melhor, tanto os processos de producao dos materiais, como os mecanismos que regulam a sensibilidade dos dispositivos aos gases, de modo a orientar adequadamente a investigacao dos novos materiais, nomeadamente no que se refere a optimizacao dos parâmetros que nao satisfazem ainda os requisitos do mercado. Um dos materiais que tem mostrado melhores qualidades para aplicacao em sensores de gases de tipo resistivo e o dioxido de estanho. Este material tem sido produzido sob diversas formas e usando diferentes tecnicas, como sejam: sol-gel [1], pulverizacao catodica (sputtering) por magnetrao [2-4], sinterizacao de pos [5, 6], ablacao laser [7] ou RGTO [8]. Os resultados obtidos revelam que as caracteristicas dos dispositivos sao muito dependentes das tecnicas usadas na sua producao. A deposicao usando sputtering reactivo por magnetrao e uma tecnica que permite obter filmes finos de oxido de estanho com diferentes caracteristicas, quer do ponto de vista da estrutura, quer da composicao, e por isso, tambem, com diferentes sensibilidades aos gases. No âmbito deste trabalho, foram produzidos filmes de SnO2 usando sputtering DC reactivo com diferentes condicoes de deposicao. Os substratos usados foram lâminas de vidro e o alvo foi estanho com 99.9% de pureza. Foi estudada a influencia da atmosfera de deposicao, da pressao parcial do O2, da

  7. Smart gas sensors for mitigating environments

    International Nuclear Information System (INIS)

    Azad, A.M.

    1997-01-01

    From the viewpoint of industrial and automobile exhaust pollution control sensors capable of detecting and metering the concentration of harmful gasers such as carbon monoxide, hydrogen, hydrocarbons, NO sub x, SO sub x, etc, in the ambient are desired. Solid state gas sensors based on semiconducting metal oxides have been widely used for the detection and metering of a host of reducing gases, albeit with varying degrees of success. In this presentation, development aspects of new solid-state CO and H2 sensors are described. Benevolent effect of second phases and catalyst on the sensing characteristics, and the possible sensing mechanism are discussed. In the case of titania-based CO sensors, test results in a Ford V6 engine under programmed near-stoichiometric combustion conditions are also presented. Some new concepts in the area of reliable metering of humidity (water content) in the ambient are briefly highlighted. (author)

  8. Needle-type environmental microsensors: design, construction and uses of microelectrodes and multi-analyte MEMS sensor arrays

    International Nuclear Information System (INIS)

    Lee, Woo Hyoung; Bishop, Paul L; Lee, Jin-Hwan; Choi, Woo-Hyuck; Papautsky, Ian; Hosni, Ahmed A

    2011-01-01

    The development of environmental microsensor techniques is a revolutionary advance in the measurement of both absolute levels and changes in chemical species in the field of environmental engineered and natural systems. The tiny tip (5–15 µm diameter) of microsensors makes them very attractive experimental tools for direct measurements of the chemical species of interest inside biological samples (e.g., biofilm, flocs). Microelectrodes fabricated from pulled micropipettes (e.g., dissolved oxygen, oxidation–reduction potential, ion-selective microelectrode) have contributed to greater understanding of biological mechanisms for decades using microscopic monitoring, and currently microelectromechanical system (MEMS) microfabrication technologies are being successfully applied to fabricate multi-analyte sensor systems for in situ monitoring. This review focuses on needle-type environmental microsensor technology, including microelectrodes and multi-analyte MEMS sensor arrays. Design, construction and applications to biofilm research of these sensors are described. Practical methods for biofilm microprofile measurements are presented and several in situ applications for a biofilm study are highlighted. Ultimately, the developed needle-type microsensors combined with molecular biotechnology (such as microscopic observation with fluorescent probes) show the tremendous promise of micro-environmental sensor technology. (topical review)

  9. A Power-Efficient Capacitive Read-Out Circuit With Parasitic-Cancellation for MEMS Cochlea Sensors.

    Science.gov (United States)

    Wang, Shiwei; Koickal, Thomas Jacob; Hamilton, Alister; Mastropaolo, Enrico; Cheung, Rebecca; Abel, Andrew; Smith, Leslie S; Wang, Lei

    2016-02-01

    This paper proposes a solution for signal read-out in the MEMS cochlea sensors that have very small sensing capacitance and do not have differential sensing structures. The key challenge in such sensors is the significant signal degradation caused by the parasitic capacitance at the MEMS-CMOS interface. Therefore, a novel capacitive read-out circuit with parasitic-cancellation mechanism is developed; the equivalent input capacitance of the circuit is negative and can be adjusted to cancel the parasitic capacitance. Chip results prove that the use of parasitic-cancellation is able to increase the sensor sensitivity by 35 dB without consuming any extra power. In general, the circuit follows a low-degradation low-amplification approach which is more power-efficient than the traditional high-degradation high-amplification approach; it employs parasitic-cancellation to reduce the signal degradation and therefore a lower gain is required in the amplification stage. Besides, the chopper-stabilization technique is employed to effectively reduce the low-frequency circuit noise and DC offsets. As a result of these design considerations, the prototype chip demonstrates the capability of converting a 7.5 fF capacitance change of a 1-Volt-biased 0.5 pF capacitive sensor pair into a 0.745 V signal-conditioned output at the cost of only 165.2 μW power consumption.

  10. A Micro-Force Sensor with Slotted-Quad-Beam Structure for Measuring the Friction in MEMS Bearings

    Science.gov (United States)

    Liu, Huan; Yang, Shuming; Zhao, Yulong; Jiang, Zhuangde; Liu, Yan; Tian, Bian

    2013-01-01

    Presented here is a slotted-quad-beam structure sensor for the measurement of friction in micro bearings. Stress concentration slots are incorporated into a conventional quad-beam structure to improve the sensitivity of force measurements. The performance comparison between the quad-beam structure sensor and the slotted-quad-beam structure sensor are performed by theoretical modeling and finite element (FE) analysis. A hollow stainless steel probe is attached to the mesa of the sensor chip by a tailor-made organic glass fixture. Concerning the overload protection of the fragile beams, a glass wafer is bonded onto the bottom of sensor chip to limit the displacement of the mesa. The calibration of the packaged device is experimentally performed by a tri-dimensional positioning stage, a precision piezoelectric ceramic and an electronic analytical balance, which indicates its favorable sensitivity and overload protection. To verify the potential of the proposed sensor being applied in micro friction measurement, a measurement platform is established. The output of the sensor reflects the friction of bearing resulting from dry friction and solid lubrication. The results accord with the theoretical modeling and demonstrate that the sensor has the potential application in measuring the micro friction force under stable stage in MEMS machines. PMID:24084112

  11. A micro-force sensor with slotted-quad-beam structure for measuring the friction in MEMS bearings.

    Science.gov (United States)

    Liu, Huan; Yang, Shuming; Zhao, Yulong; Jiang, Zhuangde; Liu, Yan; Tian, Bian

    2013-09-30

    Presented here is a slotted-quad-beam structure sensor for the measurement of friction in micro bearings. Stress concentration slots are incorporated into a conventional quad-beam structure to improve the sensitivity of force measurements. The performance comparison between the quad-beam structure sensor and the slotted-quad-beam structure sensor are performed by theoretical modeling and finite element (FE) analysis. A hollow stainless steel probe is attached to the mesa of the sensor chip by a tailor-made organic glass fixture. Concerning the overload protection of the fragile beams, a glass wafer is bonded onto the bottom of sensor chip to limit the displacement of the mesa. The calibration of the packaged device is experimentally performed by a tri-dimensional positioning stage, a precision piezoelectric ceramic and an electronic analytical balance, which indicates its favorable sensitivity and overload protection. To verify the potential of the proposed sensor being applied in micro friction measurement, a measurement platform is established. The output of the sensor reflects the friction of bearing resulting from dry friction and solid lubrication. The results accord with the theoretical modeling and demonstrate that the sensor has the potential application in measuring the micro friction force under stable stage in MEMS machines.

  12. A Micro-Force Sensor with Slotted-Quad-Beam Structure for Measuring the Friction in MEMS Bearings

    Directory of Open Access Journals (Sweden)

    Yan Liu

    2013-09-01

    Full Text Available Presented here is a slotted-quad-beam structure sensor for the measurement of friction in micro bearings. Stress concentration slots are incorporated into a conventional quad-beam structure to improve the sensitivity of force measurements. The performance comparison between the quad-beam structure sensor and the slotted-quad-beam structure sensor are performed by theoretical modeling and finite element (FE analysis. A hollow stainless steel probe is attached to the mesa of the sensor chip by a tailor-made organic glass fixture. Concerning the overload protection of the fragile beams, a glass wafer is bonded onto the bottom of sensor chip to limit the displacement of the mesa. The calibration of the packaged device is experimentally performed by a tri-dimensional positioning stage, a precision piezoelectric ceramic and an electronic analytical balance, which indicates its favorable sensitivity and overload protection. To verify the potential of the proposed sensor being applied in micro friction measurement, a measurement platform is established. The output of the sensor reflects the friction of bearing resulting from dry friction and solid lubrication. The results accord with the theoretical modeling and demonstrate that the sensor has the potential application in measuring the micro friction force under stable stage in MEMS machines.

  13. Bimodular high temperature planar oxygen gas sensor

    Science.gov (United States)

    Sun, Xiangcheng; Liu, Yixin; Gao, Haiyong; Gao, Puxian; Lei, Yu

    2014-08-01

    A bimodular planar O2 sensor was fabricated using NiO nanoparticles (NPs) thin film coated yttria-stabilized zirconia (YSZ) substrate. The thin film was prepared by radio frequency (r.f.) magnetron sputtering of NiO on YSZ substrate, followed by high temperature sintering. The surface morphology of NiO nanoparticles film was characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). X-ray diffraction (XRD) patterns of NiO NPs thin film before and after high temperature O2 sensing demonstrated that the sensing material possesses a good chemical and structure stability. The oxygen detection experiments were performed at 500 °C, 600 °C and 800 °C using the as-prepared bimodular O2 sensor under both potentiometric and resistance modules. For the potentiometric module, a linear relationship between electromotive force (EMF) output of the sensor and the logarithm of O2 concentration was observed at each operating temperature, following the Nernst law. For the resistance module, the logarithm of electrical conductivity was proportional to the logarithm of oxygen concentration at each operating temperature, in good agreement with literature report. In addition, this bimodular sensor shows sensitive, reproducible and reversible response to oxygen under both sensing modules. Integration of two sensing modules into one sensor could greatly enrich the information output and would open a new venue in the development of high temperature gas sensors.

  14. Bimodular high temperature planar oxygen gas sensor

    Directory of Open Access Journals (Sweden)

    Xiangcheng eSun

    2014-08-01

    Full Text Available A bimodular planar O2 sensor was fabricated using NiO nanoparticles (NPs thin film coated yttria-stabilized zirconia (YSZ substrate. The thin film was prepared by radio frequency (r.f. magnetron sputtering of NiO on YSZ substrate, followed by high temperature sintering. The surface morphology of NiO nanoparticles film was characterized by atomic force microscopy (AFM and scanning electron microscopy (SEM. X-ray diffraction (XRD patterns of NiO NPs thin film before and after high temperature O2 sensing demonstrated that the sensing material possesses a good chemical and structure stability. The oxygen detection experiments were performed at 500 °C, 600 °C and 800 °C using the as-prepared bimodular O2 sensor under both potentiometric and resistance modules. For the potentiometric module, a linear relationship between electromotive force (EMF output of the sensor and the logarithm of O2 concentration was observed at each operating temperature, following the Nernst law. For the resistance module, the logarithm of electrical conductivity was proportional to the logarithm of oxygen concentration at each operating temperature, in good agreement with literature report. In addition, this bimodular sensor shows sensitive, reproducible and reversible response to oxygen under both sensing modules. Integration of two sensing modules into one sensor could greatly enrich the information output and would open a new venue in the development of high temperature gas sensors.

  15. A feasibility study on embedded micro-electromechanical sensors and systems (MEMS) for monitoring highway structures.

    Science.gov (United States)

    2011-06-01

    Micro-electromechanical systems (MEMS) provide vast improvements over existing sensing methods in the context of structural health monitoring (SHM) of highway infrastructure systems, including improved system reliability, improved longevity and enhan...

  16. Capacitive MEMS-based sensors : thermo-mechanical stability and charge trapping

    NARCIS (Netherlands)

    van Essen, M.C.

    2009-01-01

    Micro-Electro Mechanical Systems (MEMS) are generally characterized as miniaturized systems with electrostatically driven moving parts. In many cases, the electrodes are capacitively coupled. This basic scheme allows for a plethora of specifications and functionality. This technology has presently

  17. MEMS-based Optic Fiber Fabry-Perot Sensor for Underwater Acoustic Measurement with A Wavelength-switched System

    Science.gov (United States)

    Xia, J.; Y Wang, F.; Luo, H.; Hu, Y. M.; Xiong, S. D.

    2017-12-01

    In this paper, a MEMS-based extrinsic Farby-Perot Interferometric (EFPI) acoustic pressure acoustic sensor is presented. The diaphragm structure is used as the second reflected surface, and the sensitive surface to acoustic pressure. A wavelength-switched phase demodulation system for EFPI sensors is used for acoustic signal recovery. The modified phase demodulation system has been demonstrated to recover the signal to a stable intensity fluctuation level of ±0.5 dB at the test frequency of 2000 Hz. In the test depth of 50cm, the sensor has a resonant frequency of 3.7 kHz, a flat frequency range of 10-800Hz, and a corresponding acoustic pressure sensitivity of -159 dB re. 1/μPa.

  18. New Vision Sensor to Measure Gas Pressure

    Directory of Open Access Journals (Sweden)

    Murawski Krzysztof

    2015-06-01

    Full Text Available The paper presents the construction and operation of a video sensor developed for video-manometer. In the publication the use of video-manometer for measuring gas pressure is presented. A characteristic feature of the device is pressure measurement based on diaphragm deformation and digital image processing. Presented measuring technique eliminates restrictions in the construction of the measuring apparatus arising from non-linear nature of diaphragm deformation. It also allows performing measurements of gas pressure, also of explosive gas, providing galvanic isolation between the factor measured and the measuring device. The paper presents the results of video-manometer calibration and measurements taken during the laboratory tests. It has been shown that the developed video-manometer, that is equipped with a flat silicone diaphragm, allows measuring the gas pressure in the range of 0 – 100 mbar with an error less than 2 %. In the experiments the CO2 pressure was measured.

  19. The Mechanical and Electrical Effects of MEMS Capacitive Pressure Sensor Based 3C-SiC for Extreme Temperature

    Directory of Open Access Journals (Sweden)

    N. Marsi

    2014-01-01

    Full Text Available This paper discusses the mechanical and electrical effects on 3C-SiC and Si thin film as a diaphragm for MEMS capacitive pressure sensor operating for extreme temperature which is 1000 K. This work compares the design of a diaphragm based MEMS capacitive pressure sensor employing 3C-SiC and Si thin films. A 3C-SiC diaphragm was bonded with a thickness of 380 μm Si substrate, and a cavity gap of 2.2 μm is formed between the wafers. The MEMS capacitive pressure sensor designs were simulated using COMSOL ver 4.3 software to compare the diaphragm deflection, capacitive performance analysis, von Mises stress, and total electrical energy performance. Both materials are designed with the same layout dimensional with different thicknesses of the diaphragm which are 1.0 μm, 1.6 μm, and 2.2 μm. It is observed that the 3C-SiC thin film is far superior materials to Si thin film mechanically in withstanding higher applied pressures and temperatures. For 3C-SiC and Si, the maximum von Mises stress achieved is 148.32 MPa and 125.48 MPa corresponding to capacitance value which is 1.93 pF and 1.22 pF, respectively. In terms of electrical performance, the maximum output capacitance of 1.93 pF is obtained with less total energy of 5.87 × 10−13 J, thus having a 50% saving as compared to Si.

  20. Optical-Interferometry-Based CMOS-MEMS Sensor Transduced by Stress-Induced Nanomechanical Deflection

    Science.gov (United States)

    Maruyama, Satoshi; Hizawa, Takeshi; Takahashi, Kazuhiro; Sawada, Kazuaki

    2018-01-01

    We developed a Fabry–Perot interferometer sensor with a metal-oxide-semiconductor field-effect transistor (MOSFET) circuit for chemical sensing. The novel signal transducing technique was performed in three steps: mechanical deflection, transmittance change, and photocurrent change. A small readout photocurrent was processed by an integrated source follower circuit. The movable film of the sensor was a 350-nm-thick polychloro-para-xylylene membrane with a diameter of 100 µm and an air gap of 300 nm. The linearity of the integrated source follower circuit was obtained. We demonstrated a gas response using 80-ppm ethanol detected by small membrane deformation of 50 nm, which resulted in an output-voltage change with the proposed high-efficiency transduction. PMID:29304011

  1. Gas sensor with multiple internal reference electrodes and sensing electrodes

    DEFF Research Database (Denmark)

    2016-01-01

    The invention relates to a potentiometric gas sensor, or potentiometric gas detection element, with multiple internal reference electrodes and multiple sensing electrodes for determining the concentrations of gas components in a gaseous mixture. The sensor for gas detection comprises: a solid...

  2. Effects of electron beam irradiation on tin dioxide gas sensors

    Indian Academy of Sciences (India)

    WINTEC

    Electron beam; irradiation; gas sensor; tin dioxide. 1. Introduction. The theory, fabrication and application of semiconducting gas sensors, has been well developed in the last thirty years. However, their limited selectivity and sensitivity are still problematic. The usual methods to improve gas sensing properties of SnO2 gas ...

  3. Sol-Gel Thin Films for Plasmonic Gas Sensors

    Science.gov (United States)

    Della Gaspera, Enrico; Martucci, Alessandro

    2015-01-01

    Plasmonic gas sensors are optical sensors that use localized surface plasmons or extended surface plasmons as transducing platform. Surface plasmons are very sensitive to dielectric variations of the environment or to electron exchange, and these effects have been exploited for the realization of sensitive gas sensors. In this paper, we review our research work of the last few years on the synthesis and the gas sensing properties of sol-gel based nanomaterials for plasmonic sensors. PMID:26184216

  4. Mocvd of Tin Oxide for Gas Sensors.

    Science.gov (United States)

    Weglicki, Peter Stanislaw

    1990-01-01

    Available from UMI in association with The British Library. Requires signed TDF. Thin films of a wide variety of materials can be produced using an assortment of physical and chemical techniques. Such techniques are reviewed and compared, with particular reference to the deposition of tin oxide films. In the present study, MOCVD (Metal organic chemical vapour deposition) was used to grow thin films of tin oxide from dibutyltin diacetate precursor on a variety of substrates. A series of reactor prototypes were developed in accordance with specific requirements of reproducibility and process control. The evolution of the designs leading to the final working system is detailed. The theory of MOCVD is given with particular reference to the reactor used in this project. The effects of various deposition parameters on tin oxide film growth rates were investigated, and the results are discussed with reference to the deposition kinetics in the system. Films were characterised by optical interferometry, optical and electron microscopy, X-ray diffraction, Rutherford backscattering and electrical measurements. The films were generally uniform, conducting and polycrystalline, and were comprised of very small grains, resulting in a high density. A specific application of metal oxide materials is in solid state gas sensors, which are available in various forms and operate according to different mechanisms. These are compared and a detailed account is given on the theory of operation of surface conductivity modulated devices. The application of such devices based on tin oxide in thin film form was investigated in the present work. The prepared sensor samples were comprised of very small grains, resulting in a high density. The observation that preferred (310) orientation occured in thicker films, can be attributed to dendritic growth. The sensors generally showed response to numerous reducing gas ambients, although there was evidence of a degree of selectivity against methane

  5. Trace gas sensing using quantum cascade lasers and a fiber-coupled optoacoustic sensor: Application to formaldehyde

    International Nuclear Information System (INIS)

    Elia, A; Lugara, P M; Scamarcio, G; Spagnolo, V; Di Franco, C

    2010-01-01

    We will report here on the design and realization of an optoacoustic sensor for the detection of formaldehyde. The sensor consists of a commercial QCL and a resonant PA cell. Two different cell configurations have been investigated: a 'standard' H cell and an innovative T-cell with an optical fiber directly inserted into. Two different type of sound detector have been employed: electret microphones and optical MEMS-based microphone. As possible applications, we will describe the results obtained in the detection of formaldehyde (CH 2 O), a gas of great interest for industrial processes and environmental monitoring.

  6. Gas Main Sensor and Communications Network System

    Energy Technology Data Exchange (ETDEWEB)

    Hagen Schempf

    2006-05-31

    Automatika, Inc. was contracted by the Department of Energy (DOE) and with co-funding from the Northeast Gas Association (NGA), to develop an in-pipe natural gas prototype measurement and wireless communications system for assessing and monitoring distribution networks. This projected was completed in April 2006, and culminated in the installation of more than 2 dozen GasNet nodes in both low- and high-pressure cast-iron and steel mains owned by multiple utilities in the northeastern US. Utilities are currently logging data (off-line) and monitoring data in real time from single and multiple networked sensors over cellular networks and collecting data using wireless bluetooth PDA systems. The system was designed to be modular, using in-pipe sensor-wands capable of measuring, flow, pressure, temperature, water-content and vibration. Internal antennae allowed for the use of the pipe-internals as a waveguide for setting up a sensor network to collect data from multiple nodes simultaneously. Sensor nodes were designed to be installed with low- and no-blow techniques and tools. Using a multi-drop bus technique with a custom protocol, all electronics were designed to be buriable and allow for on-board data-collection (SD-card), wireless relaying and cellular network forwarding. Installation options afforded by the design included direct-burial and external polemounted variants. Power was provided by one or more batteries, direct AC-power (Class I Div.2) and solar-array. The utilities are currently in a data-collection phase and intend to use the collected (and processed) data to make capital improvement decisions, compare it to Stoner model predictions and evaluate the use of such a system for future expansion, technology-improvement and commercialization starting later in 2006.

  7. Compact portable QEPAS multi-gas sensor

    Science.gov (United States)

    Dong, Lei; Kosterev, Anatoliy A.; Thomazy, David; Tittel, Frank K.

    2011-01-01

    A quartz-enhanced photoacoustic spectroscopy (QEPAS) based multi-gas sensor was developed to quantify concentrations of carbon monoxide (CO), hydrogen cyanide (HCN), hydrogen chloride (HCl), and carbon dioxide (CO2) in ambient air. The sensor consists of a compact package of dimensions 25cm x 25cm x 10cm and was designed to operate at atmospheric pressure. The HCN, CO2, and HCl measurement channels are based on cw, C-band telecommunication-style packaged, fiber-coupled diode lasers, while the CO channel uses a TO can-packaged Sb diode laser as an excitation source. Moreover, the sensor incorporates rechargeable batteries and can operate on batteries for at least 8 hours. It can also operate autonomously or interact with another device (such as a computer) via a RS232 serial port. Trace gas detection limits of 7.74ppm at 4288.29cm-1 for CO, 450ppb at 6539.11 cm-1 for HCN, 1.48ppm at 5739.26 cm-1 for HCl and 97ppm at 6361.25 cm-1 for CO2 for a 1sec average time, were demonstrated.

  8. Integration of periodic structure and highly narrowband MEMS sensor to enhance crack detection ability in steel structures

    Science.gov (United States)

    Kabir, Minoo; Ozevin, Didem

    2016-09-01

    Acoustic emission method is a nondestructive evaluation method based on the propagation of elastic waves due to the sudden change in strain field caused by newly formed fracture surfaces. While the method has been successfully applied to many structures, the influence of friction emissions limits the diverse use of the method in large-scale structures. This research integrates the metamaterial geometry to block low frequency friction signals while allowing high frequency signals due to the crack growth. The phononic structure is composed of periodic arrangement of holes in a steel plate that prohibits propagation of elastic waves near the band gap of 60 kHz. The dispersion curve of the periodic structure is calculated using finite element modeling of a unit cell in COMSOL Multiphysics. As the band gap of the periodic structure is highly narrowband, the acoustic sensing is achieved by highly narrowband capacitive type Micro-Electro- Mechanical Systems (MEMS) sensors tuned to the desired stop band frequency. The integration of periodic plate design and MEMS sensors provides wave-field focusing to reduce wave attenuation, and prevent interference of secondary waves sources, such as friction, with the primary waveforms. The waveguiding feature of the designed structure is experimentally investigated and discussed in this paper.

  9. Conductive polymer nanowire gas sensor fabricated by nanoscale soft lithography

    Science.gov (United States)

    Tang, Ning; Jiang, Yang; Qu, Hemi; Duan, Xuexin

    2017-12-01

    Resistive devices composed of one-dimensional nanostructures are promising candidates for the next generation of gas sensors. However, the large-scale fabrication of nanowires is still challenging, which restricts the commercialization of such devices. Here, we report a highly efficient and facile approach to fabricating poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) nanowire chemiresistive gas sensors by nanoscale soft lithography. Well-defined sub-100 nm nanowires are fabricated on silicon substrate, which facilitates device integration. The nanowire chemiresistive gas sensor is demonstrated for NH3 and NO2 detection at room temperature and shows a limit of detection at ppb level, which is compatible with nanoscale PEDOT:PSS gas sensors fabricated with the conventional lithography technique. In comparison with PEDOT:PSS thin-film gas sensors, the nanowire gas sensor exhibits higher sensitivity and a much faster response to gas molecules.

  10. Advanced Mechatronics and MEMS Devices

    CERN Document Server

    2013-01-01

    Advanced Mechatronics and MEMS Devicesdescribes state-of-the-art MEMS devices and introduces the latest technology in electrical and mechanical microsystems. The evolution of design in microfabrication, as well as emerging issues in nanomaterials, micromachining, micromanufacturing and microassembly are all discussed at length in this volume. Advanced Mechatronics also provides a reader with knowledge of MEMS sensors array, MEMS multidimensional accelerometer, artificial skin with imbedded tactile components, as well as other topics in MEMS sensors and transducers. The book also presents a number of topics in advanced robotics and an abundance of applications of MEMS in robotics, like reconfigurable modular snake robots, magnetic MEMS robots for drug delivery and flying robots with adjustable wings, to name a few. This book also: Covers the fundamentals of advanced mechatronics and MEMS devices while also presenting new state-of-the-art methodology and technology used in the application of these devices Prese...

  11. Electrochemical high-temperature gas sensors

    Science.gov (United States)

    Saruhan, B.; Stranzenbach, M.; Yüce, A.; Gönüllü, Y.

    2012-06-01

    Combustion produced common air pollutant, NOx associates with greenhouse effects. Its high temperature detection is essential for protection of nature. Component-integration capable high-temperature sensors enable the control of combustion products. The requirements are quantitative detection of total NOx and high selectivity at temperatures above 500°C. This study reports various approaches to detect NO and NO2 selectively under lean and humid conditions at temperatures from 300°C to 800°C. All tested electrochemical sensors were fabricated in planar design to enable componentintegration. We suggest first an impedance-metric gas sensor for total NOx-detection consisting of NiO- or NiCr2O4-SE and PYSZ-electrolyte. The electrolyte-layer is about 200μm thickness and constructed of quasi-single crystalline columns. The sensing-electrode (SE) is magnetron sputtered thin-layers of NiO or NiCr2O4. Sensor sensitivity for detection of total NOx has been measured by applying impedance analysis. The cross-sensitivity to other emission gases such as CO, CO2, CH4 and oxygen (5 vol.%) has been determined under 0-1000ppm NO. Sensor maintains its high sensitivity at temperatures up to 550°C and 600°C, depending on the sensing-electrode. NiO-SE yields better selectivity to NO in the presence of oxygen and have shorter response times comparing to NiCr2O4-SE. For higher temperature NO2-sensing capability, a resistive DC-sensor having Al-doped TiO2-sensing layers has been employed. Sensor-sensitivity towards NO2 and cross-sensitivity to CO has been determined in the presence of H2O at temperatures 600°C and 800°C. NO2 concentrations varying from 25 to 100ppm and CO concentrations from 25 to 75ppm can be detected. By nano-tubular structuring of TiO2, NO2 sensitivity of the sensor was increased.

  12. Investigation of Top/bottom Electrode and Diffusion Barrier Layer for PZT thick film MEMS Sensors

    DEFF Research Database (Denmark)

    Pedersen, Thomas; Hindrichsen, Christian Carstensen; Lou-Møller, R.

    2007-01-01

    In this work screen printed piezoelectric Ferroperm PZ26 lead zirconate titanate (PZT) thick film is used for two MEMS devices. A test structure is used to investigate several aspects regarding bottom and top electrodes. 450 nm ZrO2 thin film is found to be an insufficient diffusion barrier layer...

  13. Investigation of Top/Bottom electrode and Diffusion Barrier Layer for PZT Thick Film MEMS Sensors

    DEFF Research Database (Denmark)

    Hindrichsen, Christian Carstensen; Pedersen, Thomas; Thomsen, Erik Vilain

    2008-01-01

    Top and bottom electrodes for screen printed piezoelectric lead zirconate titanate, Pb(ZrxTi1 - x)O3 (PZT) thick film are investigated with respect to future MEMS devices. Down to 100 nm thick E-beam evaporated Al and Pt films are patterned as top electrodes on the PZT using a lift-off process...

  14. Carbon-Nanotube-Based Chemical Gas Sensor

    Science.gov (United States)

    Kaul, Arunpama B.

    2010-01-01

    Conventional thermal conductivity gauges (e.g. Pirani gauges) lend themselves to applications such as leak detectors, or in gas chromatographs for identifying various gas species. However, these conventional gauges are physically large, operate at high power, and have a slow response time. A single-walled carbon-nanotube (SWNT)-based chemical sensing gauge relies on differences in thermal conductance of the respective gases surrounding the CNT as it is voltage-biased, as a means for chemical identification. Such a sensor provides benefits of significantly reduced size and compactness, fast response time, low-power operation, and inexpensive manufacturing since it can be batch-fabricated using Si integrated-circuit (IC) process technology.

  15. MEMS Flow Sensors Based on Self-Heated aGe-Thermistors in a Wheatstone Bridge.

    Science.gov (United States)

    Talic, Almir; Cerimovic, Samir; Beigelbeck, Roman; Kohl, Franz; Sauter, Thilo; Keplinger, Franz

    2015-04-28

    A thermal flow transduction method combining the advantages of calorimetric and hot-film transduction principles is developed and analyzed by Finite Element Method (FEM) simulations and confirmed experimentally. The analyses include electrothermal feedback effects of current driven NTC thermistors. Four thin-film germanium thermistors acting simultaneously as heat sources and as temperature sensors are embedded in a micromachined silicon-nitride membrane. These devices form a self-heated Wheatstone bridge that is unbalanced by convective cooling. The voltage across the bridge and the total dissipated power are exploited as output quantities. The used thin-film thermistors feature an extremely high temperature sensitivity. Combined with properly designed resistance values, a power demand in sub-1mW range enables efficient gas-flow transduction, as confirmed by measurements. Two sensor configurations with different arrangements of the membrane thermistors were examined experimentally. Moreover, we investigated the influence of different layouts on the rise time, the sensitivity, and the usable flow range by means of two-dimensional finite element simulations. The simulation results are in reasonable agreement with corresponding measurement data confirming the basic assumptions and modeling approach.

  16. MEMS Flow Sensors Based on Self-Heated aGe-Thermistors in a Wheatstone Bridge

    Directory of Open Access Journals (Sweden)

    Almir Talic

    2015-04-01

    Full Text Available A thermal flow transduction method combining the advantages of calorimetric and hot-film transduction principles is developed and analyzed by Finite Element Method (FEM simulations and confirmed experimentally. The analyses include electrothermal feedback effects of current driven NTC thermistors. Four thin-film germanium thermistors acting simultaneously as heat sources and as temperature sensors are embedded in a micromachined silicon-nitride membrane. These devices form a self-heated Wheatstone bridge that is unbalanced by convective cooling. The voltage across the bridge and the total dissipated power are exploited as output quantities. The used thin-film thermistors feature an extremely high temperature sensitivity. Combined with properly designed resistance values, a power demand in sub-1mW range enables efficient gas-flow transduction, as confirmed by measurements. Two sensor configurations with different arrangements of the membrane thermistors were examined experimentally. Moreover, we investigated the influence of different layouts on the rise time, the sensitivity, and the usable flow range by means of two-dimensional finite element simulations. The simulation results are in reasonable agreement with corresponding measurement data confirming the basic assumptions and modeling approach.

  17. MEMS for automotive and aerospace applications

    CERN Document Server

    Kraft, Michael

    2013-01-01

    MEMS for automotive and aerospace applications reviews the use of Micro-Electro-Mechanical-Systems (MEMS) in developing solutions to the unique challenges presented by the automotive and aerospace industries.Part one explores MEMS for a variety of automotive applications. The role of MEMS in passenger safety and comfort, sensors for automotive vehicle stability control applications and automotive tire pressure monitoring systems are considered, along with pressure and flow sensors for engine management, and RF MEMS for automotive radar sensors. Part two then goes on to explore MEMS for

  18. Reliable before-fabrication forecasting of normal and touch mode MEMS capacitive pressure sensor: modeling and simulation

    Science.gov (United States)

    Jindal, Sumit Kumar; Mahajan, Ankush; Raghuwanshi, Sanjeev Kumar

    2017-10-01

    An analytical model and numerical simulation for the performance of MEMS capacitive pressure sensors in both normal and touch modes is required for expected behavior of the sensor prior to their fabrication. Obtaining such information should be based on a complete analysis of performance parameters such as deflection of diaphragm, change of capacitance when the diaphragm deflects, and sensitivity of the sensor. In the literature, limited work has been carried out on the above-stated issue; moreover, due to approximation factors of polynomials, a tolerance error cannot be overseen. Reliable before-fabrication forecasting requires exact mathematical calculation of the parameters involved. A second-order polynomial equation is calculated mathematically for key performance parameters of both modes. This eliminates the approximation factor, and an exact result can be studied, maintaining high accuracy. The elimination of approximation factors and an approach of exact results are based on a new design parameter (δ) that we propose. The design parameter gives an initial hint to the designers on how the sensor will behave once it is fabricated. The complete work is aided by extensive mathematical detailing of all the parameters involved. Next, we verified our claims using MATLAB® simulation. Since MATLAB® effectively provides the simulation theory for the design approach, more complicated finite element method is not used.

  19. Electrical Design and Evaluation of Asynchronous Serial Bus Communication Network of 48 Sensor Platform LSIs with Single-Ended I/O for Integrated MEMS-LSI Sensors

    Science.gov (United States)

    Shao, Chenzhong; Tanaka, Shuji; Nakayama, Takahiro; Hata, Yoshiyuki

    2018-01-01

    For installing many sensors in a limited space with a limited computing resource, the digitization of the sensor output at the site of sensation has advantages such as a small amount of wiring, low signal interference and high scalability. For this purpose, we have developed a dedicated Complementary Metal-Oxide-Semiconductor (CMOS) Large-Scale Integration (LSI) (referred to as “sensor platform LSI”) for bus-networked Micro-Electro-Mechanical-Systems (MEMS)-LSI integrated sensors. In this LSI, collision avoidance, adaptation and event-driven functions are simply implemented to relieve data collision and congestion in asynchronous serial bus communication. In this study, we developed a network system with 48 sensor platform LSIs based on Printed Circuit Board (PCB) in a backbone bus topology with the bus length being 2.4 m. We evaluated the serial communication performance when 48 LSIs operated simultaneously with the adaptation function. The number of data packets received from each LSI was almost identical, and the average sampling frequency of 384 capacitance channels (eight for each LSI) was 73.66 Hz. PMID:29342923

  20. Zirconia-based solid state chemical gas sensors

    CERN Document Server

    Zhuiykov, S

    2000-01-01

    This paper presents an overview of chemical gas sensors, based on solid state technology, that are sensitive to environmental gases, such as O sub 2 , SO sub x , NO sub x , CO sub 2 and hydrocarbons. The paper is focussed on performance of electrochemical gas sensors that are based on zirconia as a solid electrolyte. The paper considers sensor structures and selection of electrode materials. Impact of interfaces on sensor performance is discussed. This paper also provides a brief overview of electrochemical properties of zirconia and their effect on sensor performance. Impact of auxiliary materials on sensors performance characteristics, such as sensitivity, selectivity, response time and recovery time, is also discussed. Dual gas sensors that can be applied for simultaneous monitoring of the concentration of both oxygen and other gas phase components, are briefly considered

  1. On Orbit Immuno-Based, Label-Free, White Blood Cell Counting System with MicroElectroMechanical Sensor (MEMS) Technology (OILWBCS-MEMS) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Aurora Flight Sciences Corporation and partner, Draper Laboratory, propose to develop an on-orbit immuno-based label-free white blood cell counting system using MEMS...

  2. On Orbit Immuno-Based, Label-Free, White Blood Cell Counting System with MicroElectroMechanical Sensor (MEMS) Technology (OILWBCS-MEMS), Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Aurora Flight Sciences Corporation and partner, Draper Laboratory, propose to develop an on-orbit immuno-based label-free white blood cell counting system using MEMS...

  3. MEMS acceleration sensor with remote optical readout for continuous power generator monitoring

    Directory of Open Access Journals (Sweden)

    Tormen Maurizio

    2015-01-01

    Full Text Available Miniaturized accelerometers with remote optical readout are required devices for the continuous monitoring of vibrations inside power generators. In turbo and hydro generators, end-winding vibrations are present during operation causing in the long term undesirable out-of-service repairs. Continuous monitoring of these vibrations is therefore mandatory. The high electromagnetic fields in the generators impose the use of devices immune to electromagnetic interferences. In this paper a MEMS based accelerometer with remote optical readout is presented. Advantages of the proposed device are the use of a differential optical signal to reject the common mode signal and noise, the reduced number of steps for the MEMS chip fabrication and for the system assembly, and the reduced package volume.

  4. Wi-Fi based Multinode M.S Level sensor in UAV’s using MEMS

    OpenAIRE

    R. Prabhakar; K. Immanuel Arokia James

    2012-01-01

    Communication networks and strategies for cooperative UAV swarms have received significant attention. The main problem in controlling autonomous vehicles needs some knowledge of its altitude angles. These angles can be measured in different ways, for instance, using a conventional inertial navigation system. A novel approach to deal these problems by modern Micro electro mechanical systems (MEMS) technologies are offering light and moderate-cost solutions, denoted as inertial measurement unit...

  5. Mechanical Robustness and Hermeticity Monitoring for MEMS Thin Film Encapsulation

    NARCIS (Netherlands)

    Santagata, F.

    2011-01-01

    Many Micro-Electro-Mechanical-Systems (MEMS) require encapsulation, to prevent delicate sensor structures being exposed to external perturbations such as dust, humidity, touching, and gas pressure. An upcoming and cost-effective way of encapsulation is zero-level packaging or thin-film

  6. Potential use of gas sensors in beef manure nutrient content ...

    African Journals Online (AJOL)

    The purpose of this study was to develop a gas sensor array to estimate the manure nutrient contents. Three metal-oxide gas sensors including methane, ammonia and hydrogen sulfide were used. Forty manure samples were collected from four beef operations in Southwest North Dakota. Manure samples were sent to be ...

  7. Fast response time alcohol gas sensor using nanocrystalline F ...

    Indian Academy of Sciences (India)

    The maximum sensitivities of both gas sensors were obtained at 623 K. Keywords. F-doped SnO2; sol–gel; gas sensor; sensitivity. 1. Introduction. Ethanol is the most popular alcohol, best known as the type of alcohol used in alcoholic beverages. Ethanol is produced primarily by fermentation and the vast majority of ethanol.

  8. A novel SnO(2)-based gas sensor.

    Science.gov (United States)

    Siroký, K; Jiresová, J

    1994-10-01

    A novel 'two-terminal' semiconductor gas sensor was developed based on a heavily Sb-doped SnO(2) film prepared by cathodic sputtering. The sensor is heated at its operational temperature by the gas sensitive film itself. A device for detecting the leakage of flammable gases, some noxious or hazardous gases can be made in this way.

  9. A Smart Gas Sensor Insensitive to Humidity and Temperature Variations

    International Nuclear Information System (INIS)

    Hajmirzaheydarali, Mohammadreza; Ghafarinia, Vahid

    2011-01-01

    The accuracy of the quantitative sensing of volatile organic compounds by chemoresistive gas sensors suffers from the fluctuations in the background atmospheric conditions. This is caused by the drift-like terms introduced in the responses by these instabilities, which should be identified and compensated. Here, a mathematical model is presented for a specific chemoresistive gas sensor, which facilitates these identification and compensation processes. The resistive gas sensor was considered as a multi-input-single-output system. Along with the steady state value of the measured sensor resistance, the ambient humidity and temperature are the inputs to the system, while the concentration level of the target gas is the output. The parameters of the model were calculated based on the experimental database. The model was simulated by the utilization of an artificial neural network. This was connected to the sensor and could deliver the correct contamination level upon receiving the measured gas response, ambient humidity and temperature.

  10. A Review of Carbon Nanotubes-Based Gas Sensors

    OpenAIRE

    Wang, Yun; Yeow, John T. W.

    2009-01-01

    Gas sensors have attracted intensive research interest due to the demand of sensitive, fast response, and stable sensors for industry, environmental monitoring, biomedicine, and so forth. The development of nanotechnology has created huge potential to build highly sensitive, low cost, portable sensors with low power consumption. The extremely high surface-to-volume ratio and hollow structure of nanomaterials is ideal for the adsorption of gas molecules. Particularly, the advent of carbon nano...

  11. Calibration transfer in temperature modulated gas sensor arrays

    OpenAIRE

    Fernández Romero, Luis; Güney, Selda; Gutiérrez Gálvez, Agustín; Marco Colás, Santiago

    2016-01-01

    Shifts in working temperature are an important issue that prevents the successful transfer of calibration models from one chemical instrument to another. This effect is of special relevance when working with gas sensor arrays modulated in temperature. In this paper, we study the use of multivariate techniques to transfer the calibration model from a temperature modulated gas sensor array to another when a global change of temperature occurs. To do so, we built 12 identical master sensor array...

  12. CMOS MEMS Fabrication Technologies and Devices

    Directory of Open Access Journals (Sweden)

    Hongwei Qu

    2016-01-01

    Full Text Available This paper reviews CMOS (complementary metal-oxide-semiconductor MEMS (micro-electro-mechanical systems fabrication technologies and enabled micro devices of various sensors and actuators. The technologies are classified based on the sequence of the fabrication of CMOS circuitry and MEMS elements, while SOI (silicon-on-insulator CMOS MEMS are introduced separately. Introduction of associated devices follows the description of the respective CMOS MEMS technologies. Due to the vast array of CMOS MEMS devices, this review focuses only on the most typical MEMS sensors and actuators including pressure sensors, inertial sensors, frequency reference devices and actuators utilizing different physics effects and the fabrication processes introduced. Moreover, the incorporation of MEMS and CMOS is limited to monolithic integration, meaning wafer-bonding-based stacking and other integration approaches, despite their advantages, are excluded from the discussion. Both competitive industrial products and state-of-the-art research results on CMOS MEMS are covered.

  13. Development of MEMS photoacoustic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Alex Lockwood; Eichenfield, Matthew S.; Griffin, Benjamin; Harvey, Heidi Alyssa; Nielson, Gregory N.; Okandan, Murat; Langlois, Eric; Resnick, Paul James; Shaw, Michael J.; Young, Ian; Givler, Richard C.; Reinke, Charles M.

    2014-01-01

    After years in the field, many materials suffer degradation, off-gassing, and chemical changes causing build-up of measurable chemical atmospheres. Stand-alone embedded chemical sensors are typically limited in specificity, require electrical lines, and/or calibration drift makes data reliability questionable. Along with size, these "Achilles' heels" have prevented incorporation of gas sensing into sealed, hazardous locations which would highly benefit from in-situ analysis. We report on development of an all-optical, mid-IR, fiber-optic based MEMS Photoacoustic Spectroscopy solution to address these limitations. Concurrent modeling and computational simulation are used to guide hardware design and implementation.

  14. Transfer of preheat-treated SnO 2 via a sacrificial bridge-type ZnO layer for ethanol gas sensor

    KAUST Repository

    Lee, Da Hoon

    2017-08-05

    The progress in developing the microelectromechanical system (MEMS) heater-based SnO2 gas sensors was hindered by the subsequent heat treatment of the tin oxide (SnO2), nevertheless it is required to obtain excellent sensor characteristics. During the sintering process, the MEMS heater and the contact electrodes can be degraded at such a high temperature, which could reduce the sensor response and reliability. In this research, we presented a process of preheating the printed SnO2 sensing layer on top of a sacrificial bridge-type ZnO layer at such a high temperature, followed by transferring it onto the contact electrodes of sensor device by selective etching of the sacrificial ZnO layer. Therefore, the sensor device was not exposed to the high sintering temperature. The SnO2 gas sensor fabricated by the transfer process exhibited a rectangular sensing curve behavior with a rapid response of 52 s at 20 ppm ethanol concentration. In addition, reliable and repeatable sensing characteristics were obtained even at an ethanol gas concentration of 5 ppm.

  15. An Electrochemical, Low-Frequency Seismic Micro-Sensor Based on MEMS with a Force-Balanced Feedback System.

    Science.gov (United States)

    Li, Guanglei; Wang, Junbo; Chen, Deyong; Chen, Jian; Chen, Lianhong; Xu, Chao

    2017-09-13

    Electrochemical seismic sensors are key components in monitoring ground vibration, which are featured with high performances in the low-frequency domain. However, conventional electrochemical seismic sensors suffer from low repeatability due to limitations in fabrication and limited bandwidth. This paper presents a micro-fabricated electrochemical seismic sensor with a force-balanced negative feedback system, mainly composed of a sensing unit including porous sensing micro electrodes immersed in an electrolyte solution and a feedback unit including a feedback circuit and a feedback magnet. In this study, devices were designed, fabricated, and characterized, producing comparable performances among individual devices. In addition, bandwidths and total harmonic distortions of the proposed devices with and without a negative feedback system were quantified and compared as 0.005-20 (feedback) Hz vs. 0.3-7 Hz (without feedback), 4.34 ± 0.38% (without feedback) vs. 1.81 ± 0.31% (feedback)@1 Hz@1 mm/s and 3.21 ± 0.25% (without feedback) vs. 1.13 ± 0.19% (feedback)@5 Hz@1 mm/s (n device = 6, n represents the number of the tested devices), respectively. In addition, the performances of the proposed MEMS electrochemical seismometers with feedback were compared to a commercial electrochemical seismic sensor (CME 6011), producing higher bandwidth (0.005-20 Hz vs. 0.016-30 Hz) and lower self-noise levels (-165.1 ± 6.1 dB vs. -137.7 dB at 0.1 Hz, -151.9 ± 7.5 dB vs. -117.8 dB at 0.02 Hz (n device = 6)) in the low-frequency domain. Thus, the proposed device may function as an enabling electrochemical seismometer in the fields requesting seismic monitoring at the ultra-low frequency domain.

  16. A Dual-Linear Kalman Filter for Real-Time Orientation Determination System Using Low-Cost MEMS Sensors.

    Science.gov (United States)

    Zhang, Shengzhi; Yu, Shuai; Liu, Chaojun; Yuan, Xuebing; Liu, Sheng

    2016-02-20

    To provide a long-time reliable orientation, sensor fusion technologies are widely used to integrate available inertial sensors for the low-cost orientation estimation. In this paper, a novel dual-linear Kalman filter was designed for a multi-sensor system integrating MEMS gyros, an accelerometer, and a magnetometer. The proposed filter precludes the impacts of magnetic disturbances on the pitch and roll which the heading is subjected to. The filter can achieve robust orientation estimation for different statistical models of the sensors. The root mean square errors (RMSE) of the estimated attitude angles are reduced by 30.6% under magnetic disturbances. Owing to the reduction of system complexity achieved by smaller matrix operations, the mean total time consumption is reduced by 23.8%. Meanwhile, the separated filter offers greater flexibility for the system configuration, as it is possible to switch on or off the second stage filter to include or exclude the magnetometer compensation for the heading. Online experiments were performed on the homemade miniature orientation determination system (MODS) with the turntable. The average RMSE of estimated orientation are less than 0.4° and 1° during the static and low-dynamic tests, respectively. More realistic tests on two-wheel self-balancing vehicle driving and indoor pedestrian walking were carried out to evaluate the performance of the designed MODS when high accelerations and angular rates were introduced. Test results demonstrate that the MODS is applicable for the orientation estimation under various dynamic conditions. This paper provides a feasible alternative for low-cost orientation determination.

  17. A Dual-Linear Kalman Filter for Real-Time Orientation Determination System Using Low-Cost MEMS Sensors

    Directory of Open Access Journals (Sweden)

    Shengzhi Zhang

    2016-02-01

    Full Text Available To provide a long-time reliable orientation, sensor fusion technologies are widely used to integrate available inertial sensors for the low-cost orientation estimation. In this paper, a novel dual-linear Kalman filter was designed for a multi-sensor system integrating MEMS gyros, an accelerometer, and a magnetometer. The proposed filter precludes the impacts of magnetic disturbances on the pitch and roll which the heading is subjected to. The filter can achieve robust orientation estimation for different statistical models of the sensors. The root mean square errors (RMSE of the estimated attitude angles are reduced by 30.6% under magnetic disturbances. Owing to the reduction of system complexity achieved by smaller matrix operations, the mean total time consumption is reduced by 23.8%. Meanwhile, the separated filter offers greater flexibility for the system configuration, as it is possible to switch on or off the second stage filter to include or exclude the magnetometer compensation for the heading. Online experiments were performed on the homemade miniature orientation determination system (MODS with the turntable. The average RMSE of estimated orientation are less than 0.4° and 1° during the static and low-dynamic tests, respectively. More realistic tests on two-wheel self-balancing vehicle driving and indoor pedestrian walking were carried out to evaluate the performance of the designed MODS when high accelerations and angular rates were introduced. Test results demonstrate that the MODS is applicable for the orientation estimation under various dynamic conditions. This paper provides a feasible alternative for low-cost orientation determination.

  18. Nanostructured Fiber Optic Cantilever Arrays and Hybrid MEMS Sensors for Chemical and Biological Detection, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Advancements in nano-/micro-scale sensor fabrication and molecular recognition surfaces offer promising opportunities to develop miniaturized hybrid fiber optic and...

  19. GAS MAIN SENSOR AND COMMUNICATIONS NETWORK SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Hagen Schempf

    2004-09-30

    Automatika, Inc. was contracted by the Department of Energy (DOE) and with co-funding from the New York Gas Group (NYGAS), to develop an in-pipe natural gas prototype measurement and wireless communications system for assessing and monitoring distribution networks. In Phase II of this three-phase program, an improved prototype system was built for low-pressure cast-iron and high-pressure steel (including a no-blow installation system) mains and tested in a serial-network configuration in a live network in Long Island with the support of Keyspan Energy, Inc. The experiment was carried out in several open-hole excavations over a multi-day period. The prototype units (3 total) combined sensors capable of monitoring pressure, flow, humidity, temperature and vibration, which were sampled and combined in data-packages in an in-pipe master-repeater-slave configuration in serial or ladder-network arrangements. It was verified that the system was capable of performing all data-sampling, data-storage and collection as expected, yielding interesting results as to flow-dynamics and vibration-detection. Wireless in-pipe communications were shown to be feasible and the system was demonstrated to run off in-ground battery- and above-ground solar power. The remote datalogger access and storage-card features were demonstrated and used to log and post-process system data. Real-time data-display on an updated Phase-I GUI was used for in-field demonstration and troubleshooting.

  20. Increasing the selectivity and sensitivity of gas sensors for the detection of explosives

    Science.gov (United States)

    Mallin, Daniel

    Over the past decade, the use of improvised explosive devices (IEDs) has increased, domestically and internationally, highlighting a growing need for a method to quickly and reliably detect explosive devices in both military and civilian environments before the explosive can cause damage. Conventional techniques have been successful in explosive detection, however they typically suffer from enormous costs in capital equipment and maintenance, costs in energy consumption, sampling, operational related expenses, and lack of continuous and real-time monitoring. The goal was thus to produce an inexpensive, portable sensor that continuously monitors the environment, quickly detects the presence of explosive compounds and alerts the user. In 2012, here at URI, a sensor design was proposed for the detection of triacetone triperoxide (TATP). The design entailed a thermodynamic gas sensor that measures the heat of decomposition between trace TATP vapor and a metal oxide catalyst film. The sensor was able to detect TATP vapor at the part per million level (ppm) and showed great promise for eventual commercial use, however, the sensor lacked selectivity. Thus, the specific objective of this work was to take the original sensor design proposed in 2012 and to make several key improvements to advance the sensor towards commercialization. It was demonstrated that a sensor can be engineered to detect TATP and ignore the effects of interferent H2O2 molecules by doping SnO2 films with varying amounts of Pd. Compared with a pure SnO2 catalyst, a SnO2, film doped with 8 wt. % Pd had the highest selectivity between TATP and H2O2. Also, at 12 wt. % Pd, the response to TATP and H2O2 was enhanced, indicating that sensitivity, not only selectivity, can be increased by modifying the composition of the catalyst. An orthogonal detection system was demonstrated. The platform consists of two independent sensing mechanisms, one thermodynamic and one conductometric, which take measurements from

  1. Carbeto de Silício como Material Base para Sensores MEMS de Uso Aeroespacial: Uma Visão Geral

    OpenAIRE

    Fraga,M.A.; Pessoa,R. S.; Massi,M.; Maciel,H. S.

    2014-01-01

    Este artigo discute o emprego do carbeto de silício (SiC), na forma de substrato e filme fino, em sensores MEMS (Micro-Electro-Mechanical Systems) para aplicações em ambientes sujeitos a condições extremas, especialmente no setor aeroespacial. As propriedades físicas e químicas do SiC que o tornam um material adequado para dispositivos eletrônicos e sensores são descritas. Os conceitos, evolução e aplicações da tecnologia MEMS são apresentados. Uma visão geral sobre o estágio atual de desenvo...

  2. Modeling of a Piezoelectric MEMS Micropump Dedicated to Insulin Delivery and Experimental Validation Using Integrated Pressure Sensors: Application to Partial Occlusion Management

    Directory of Open Access Journals (Sweden)

    S. Fournier

    2017-01-01

    Full Text Available A numerical model based on equivalent electrical networks has been built to simulate the dynamic behavior of a positive-displacement MEMS micropump dedicated to insulin delivery. This device comprises a reservoir in direct communication with the inlet check valve, a pumping membrane actuated by a piezo actuator, two integrated piezoresistive pressure sensors, an anti-free-flow check valve at the outlet, and finally a fluidic pathway up to the patient cannula. The pressure profiles delivered by the sensors are continuously analyzed during the therapy in order to detect failures like occlusion. The numerical modeling is a reliable way to better understand the behavior of the micropump in case of failure. The experimental pressure profiles measured during the actuation phase have been used to validate the numerical modeling. The effect of partial occlusion on the pressure profiles has been also simulated. Based on this analysis, a new management of partial occlusion for MEMS micropump is finally proposed.

  3. Meso-/Nanoporous Semiconducting Metal Oxides for Gas Sensor Applications

    Directory of Open Access Journals (Sweden)

    Nguyen Duc Hoa

    2015-01-01

    Full Text Available Development and/or design of new materials and/or structures for effective gas sensor applications with fast response and high sensitivity, selectivity, and stability are very important issues in the gas sensor technology. This critical review introduces our recent progress in the development of meso-/nanoporous semiconducting metal oxides and their applications to gas sensors. First, the basic concepts of resistive gas sensors and the recent synthesis of meso-/nanoporous metal oxides for gas sensor applications are introduced. The advantages of meso-/nanoporous metal oxides are also presented, taking into account the crystallinity and ordered/disordered porous structures. Second, the synthesis methods of meso-/nanoporous metal oxides including the soft-template, hard-template, and temple-free methods are introduced, in which the advantages and disadvantages of each synthetic method are figured out. Third, the applications of meso-/nanoporous metal oxides as gas sensors are presented. The gas nanosensors are designed based on meso-/nanoporous metal oxides for effective detection of toxic gases. The sensitivity, selectivity, and stability of the meso-/nanoporous gas nanosensors are also discussed. Finally, some conclusions and an outlook are presented.

  4. Design and characterization of in-plane MEMS yaw rate sensor

    Indian Academy of Sciences (India)

    matching the drive and the sense mode frequencies. Based on these factors, the yaw rate sensor is designed and finally realized using surface micromachining. The in- plane motion of the sensor is experimentally characterized to determine the sense and the drive mode frequencies, and corresponding damping ratios.

  5. Direct media exposure of MEMS multi-sensor systems using a potted-tube packaging concept

    DEFF Research Database (Denmark)

    Hyldgård, Anders; Birkelund, Karen; Janting, Jakob

    2008-01-01

    in the filling material is measured. The packaging concept is used to encapsulate a microfabricated multi-sensor (measuring temperature, water conductivity, pressure and light intensity). The direct exposure of the sensors results in high sensitivity and fast response time. The design of an elongated multi...

  6. Miniaturized Planar Room Temperature Ionic Liquid Electrochemical Gas Sensor for Rapid Multiple Gas Pollutants Monitoring.

    Science.gov (United States)

    Wan, Hao; Yin, Heyu; Lin, Lu; Zeng, Xiangqun; Mason, Andrew J

    2018-02-01

    The growing impact of airborne pollutants and explosive gases on human health and occupational safety has escalated the demand of sensors to monitor hazardous gases. This paper presents a new miniaturized planar electrochemical gas sensor for rapid measurement of multiple gaseous hazards. The gas sensor features a porous polytetrafluoroethylene substrate that enables fast gas diffusion and room temperature ionic liquid as the electrolyte. Metal sputtering was utilized for platinum electrodes fabrication to enhance adhesion between the electrodes and the substrate. Together with carefully selected electrochemical methods, the miniaturized gas sensor is capable of measuring multiple gases including oxygen, methane, ozone and sulfur dioxide that are important to human health and safety. Compared to its manually-assembled Clark-cell predecessor, this sensor provides better sensitivity, linearity and repeatability, as validated for oxygen monitoring. With solid performance, fast response and miniaturized size, this sensor is promising for deployment in wearable devices for real-time point-of-exposure gas pollutant monitoring.

  7. Triboelectric Hydrogen Gas Sensor with Pd Functionalized Surface

    Directory of Open Access Journals (Sweden)

    Sung-Ho Shin

    2016-10-01

    Full Text Available Palladium (Pd-based hydrogen (H2 gas sensors have been widely investigated thanks to its fast reaction and high sensitivity to hydrogen. Various sensing mechanisms have been adopted for H2 gas sensors; however, all the sensors must be powered through an external battery. We report here an H2 gas sensor that can detect H2 by measuring the output voltages generated during contact electrification between two friction surfaces. When the H2 sensor, composed of Pd-coated ITO (indium tin oxide and PET (polyethylene Terephthalate film, is exposed to H2, its output voltage is varied in proportion to H2 concentration because the work function (WF of Pd-coated surface changes, altering triboelectric charging behavior. Specifically, the output voltage of the sensor is gradually increased as exposing H2 concentration increases. Reproducible and sensitive sensor response was observed up 1% H2 exposure. The approach introduced here can easily be adopted to development of triboelectric gas sensors detecting other gas species.

  8. n⁺ GaAs/AuGeNi-Au Thermocouple-Type RF MEMS Power Sensors Based on Dual Thermal Flow Paths in GaAs MMIC.

    Science.gov (United States)

    Zhang, Zhiqiang; Liao, Xiaoping

    2017-06-17

    To achieve radio frequency (RF) power detection, gain control, and circuit protection, this paper presents n⁺ GaAs/AuGeNi-Au thermocouple-type RF microelectromechanical system (MEMS) power sensors based on dual thermal flow paths. The sensors utilize a conversion principle of RF power-heat-voltage, where a thermovoltage is obtained as the RF power changes. To improve the heat transfer efficiency and the sensitivity, structures of two heat conduction paths are designed: one in which a thermal slug of Au is placed between two load resistors and hot junctions of the thermocouples, and one in which a back cavity is fabricated by the MEMS technology to form a substrate membrane underneath the resistors and the hot junctions. The improved sensors were fabricated by a GaAs monolithic microwave integrated circuit (MMIC) process. Experiments show that these sensors have reflection losses of less than -17 dB up to 12 GHz. At 1, 5, and 10 GHz, measured sensitivities are about 63.45, 53.97, and 44.14 µ V/mW for the sensor with the thermal slug, and about 111.03, 94.79, and 79.04 µ V/mW for the sensor with the thermal slug and the back cavity, respectively.

  9. n+ GaAs/AuGeNi-Au Thermocouple-Type RF MEMS Power Sensors Based on Dual Thermal Flow Paths in GaAs MMIC

    Directory of Open Access Journals (Sweden)

    Zhiqiang Zhang

    2017-06-01

    Full Text Available To achieve radio frequency (RF power detection, gain control, and circuit protection, this paper presents n+ GaAs/AuGeNi-Au thermocouple-type RF microelectromechanical system (MEMS power sensors based on dual thermal flow paths. The sensors utilize a conversion principle of RF power-heat-voltage, where a thermovoltage is obtained as the RF power changes. To improve the heat transfer efficiency and the sensitivity, structures of two heat conduction paths are designed: one in which a thermal slug of Au is placed between two load resistors and hot junctions of the thermocouples, and one in which a back cavity is fabricated by the MEMS technology to form a substrate membrane underneath the resistors and the hot junctions. The improved sensors were fabricated by a GaAs monolithic microwave integrated circuit (MMIC process. Experiments show that these sensors have reflection losses of less than −17 dB up to 12 GHz. At 1, 5, and 10 GHz, measured sensitivities are about 63.45, 53.97, and 44.14 µV/mW for the sensor with the thermal slug, and about 111.03, 94.79, and 79.04 µV/mW for the sensor with the thermal slug and the back cavity, respectively.

  10. Gas Sensors Based on Polymer Field-Effect Transistors

    Directory of Open Access Journals (Sweden)

    Aifeng Lv

    2017-01-01

    Full Text Available This review focuses on polymer field-effect transistor (PFET based gas sensor with polymer as the sensing layer, which interacts with gas analyte and thus induces the change of source-drain current (ΔISD. Dependent on the sensing layer which can be semiconducting polymer, dielectric layer or conducting polymer gate, the PFET sensors can be subdivided into three types. For each type of sensor, we present the molecular structure of sensing polymer, the gas analyte and the sensing performance. Most importantly, we summarize various analyte–polymer interactions, which help to understand the sensing mechanism in the PFET sensors and can provide possible approaches for the sensor fabrication in the future.

  11. Harsh Environment Gas Sensor Array for Venus Atmospheric Measurements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Makel Engineering and the Ohio State University propose to develop a harsh environment tolerant gas sensor array for atmospheric analysis in future Venus missions....

  12. Compact Sensor for Isotope and Trace Gas Analysis, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop and demonstrate a new sensor platform for isotope and trace-gas analysis that is appropriate for future planetary missions. Among other...

  13. Silicon microring refractometric sensor for atmospheric CO(2) gas monitoring.

    Science.gov (United States)

    Mi, Guangcan; Horvath, Cameron; Aktary, Mirwais; Van, Vien

    2016-01-25

    We report a silicon photonic refractometric CO(2) gas sensor operating at room temperature and capable of detecting CO(2) gas at atmospheric concentrations. The sensor uses a novel functional material layer based on a guanidine polymer derivative, which is shown to exhibit reversible refractive index change upon absorption and release of CO(2) gas molecules, and does not require the presence of humidity to operate. By functionalizing a silicon microring resonator with a thin layer of the polymer, we could detect CO(2) gas concentrations in the 0-500ppm range with a sensitivity of 6 × 10(-9) RIU/ppm and a detection limit of 20ppm. The microring transducer provides a potential integrated solution in the development of low-cost and compact CO(2) sensors that can be deployed as part of a sensor network for accurate environmental monitoring of greenhouse gases.

  14. Compact, Robust, Low Power High Sensitivity Gas Sensor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Miniaturized gas sensors with high sensitivity that are compact, low power and low weight are needed to support for NASA's airborne science missions, particularly...

  15. A novel method of measuring spatial rotation angle using MEMS tilt sensors

    International Nuclear Information System (INIS)

    Cao, Jian’an; Zhu, Xin; Zhang, Leping; Wu, Hao

    2017-01-01

    This paper presents a novel method of measuring spatial rotation angle with a dual-axis micro-electro-mechanical systems tilt sensor. When the sensor is randomly mounted on the surface of the rotating object, there are three unpredictable and unknown mounting position parameters: α , the sensor’s swing angle on the measuring plane; β , the angle between the rotation axis and the horizontal plane; and γ , the angle between the measuring plane and the rotation axis. Thus, the sensor’s spatial rotation model is established to describe the relationship between the measuring axis, rotation axis, and horizontal plane, and the corresponding analytical equations are derived. Furthermore, to eliminate the deviation caused by the uncertain direction of the rotation axis, an extra perpendicularly mounted, single-axis tilt sensor is combined with the dual-axis tilt sensor, forming a three-axis tilt sensor. Then, by measuring the sensors’ three tilts and solving the model’s equations, the object’s spatial rotation angle is obtained. Finally, experimental results show that the developed tilt sensor is capable of measuring spatial rotation angle in the range of  ±180° with an accuracy of 0.2° if the angle between the rotation axis and the horizontal plane is less than 75°. (paper)

  16. Fabrication of a gas sensor array with micro-wells for VOCs gas sensing based on polymer/carbon nanotube thin films

    Science.gov (United States)

    Xie, Guangzhong; Xie, Tao; Zhu, Tao; Jiang, Yadong; Tai, Huiling

    2014-08-01

    In this paper, gas sensor array with micro-well was designed and prepared by Micro Electro-Mechanical Systems (MEMS) technology. The micro-well and interdigital electrodes of sensor array were prepared using photolithography process, reactive ion etching (RIE) process, wet etching and conventional vacuum evaporation. In the manufacture process of the gas sensor array, KOH wet etching process was mainly discussed. The optimum etching processing parameters were as follows: 30 wt% KOH solution at 80 °C, a cooling back-flow device and a magnetic stirrer. The multi-walled carbon nanotubes (MWCNTs)-polyethyleneoxide (PEO) and MWNTs-Polyvinylpyrrolidone (PVP) composite films were utilized as sensitive layers to test gas-sensing properties. Response performances of MWCNTs- PEO and MWNTs-PVP composite films to toluene vapor and methanol vapor at room temperature were investigated. The results revealed that the sensor array showed a larger sensitivity to toluene vapor than to methanol vapor. In addition, the sensing mechanisms were studied as well.

  17. Novel gas sensors based on carbon nanotube networks

    International Nuclear Information System (INIS)

    Sayago, I; Aleixandre, M; Horrillo, M C; Fernandez, M J; Gutierrez, J; Terrado, E; Lafuente, E; Maser, W K; Benito, A M; Martinez, M T; Munoz, E; Urriolabeitia, E P; Navarro, R

    2008-01-01

    Novel resistive gas sensors based on single-walled carbon nanotube (SWNT) networks as the active sensing element nave been investigated for gas detection. SWNTs networks were fabricated by airbrushing on alumina substrates. As-produced- and Pd-decorated SWNT materials were used as sensitive layers for the detection of NO 2 and H 2 , respectively. The studied sensors provided good response to NO 2 and H 2 as well as excellent selectivities to interfering gases.

  18. Solid-state titania-based gas sensor for liquefied petroleum gas ...

    Indian Academy of Sciences (India)

    Administrator

    Solid-state titania-based gas sensor for liquefied petroleum gas detection at room temperature. B C YADAV*, ANURADHA YADAV, TRIPTI SHUKLA and SATYENDRA SINGH. Nanomaterials and Sensors Research Laboratory, Department of Physics, University of Lucknow,. Lucknow 226 007, India. MS received 27 May ...

  19. Conductivity modeling of gas sensors based on copper ...

    African Journals Online (AJOL)

    On the lower side of the substrate, a screen-printed platinum resistor is devoted to sensor temperature control (Fig. 1). Interdigitated Pt electrodes (IDEs), polarized under 1 volt dc, are used to measure conductivity variations of the CuPc thin film which depend, in time, of gas concentration in sensor environment [26].

  20. Quartz crystal microbalance gas sensor with nanocrystalline diamond sensitive layer

    Czech Academy of Sciences Publication Activity Database

    Varga, Marián; Laposa, A.; Kulha, Pavel; Kroutil, J.; Husák, M.; Kromka, Alexander

    2015-01-01

    Roč. 252, č. 11 (2015), s. 2591-2597 ISSN 0370-1972 R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:68378271 Keywords : gas sensor * nanocrystalline diamond * quartz resonator * thickness shear mode Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 1.522, year: 2015

  1. Development of gas sensors using ZnO nanostructures

    Indian Academy of Sciences (India)

    Different ZnO nanostructures such as nanowires, nanobelts and tetrapods have been grown and used for preparation of thick film (with random grain boundaries) as well as isolated nanowire/nanobelt gas sensors. Sensitivity of different type of sensors has been studied to H2S and NO gases. The results show that the ...

  2. A Review of Carbon Nanotubes-Based Gas Sensors

    Directory of Open Access Journals (Sweden)

    Yun Wang

    2009-01-01

    Full Text Available Gas sensors have attracted intensive research interest due to the demand of sensitive, fast response, and stable sensors for industry, environmental monitoring, biomedicine, and so forth. The development of nanotechnology has created huge potential to build highly sensitive, low cost, portable sensors with low power consumption. The extremely high surface-to-volume ratio and hollow structure of nanomaterials is ideal for the adsorption of gas molecules. Particularly, the advent of carbon nanotubes (CNTs has fuelled the inventions of gas sensors that exploit CNTs' unique geometry, morphology, and material properties. Upon exposure to certain gases, the changes in CNTs' properties can be detected by various methods. Therefore, CNTs-based gas sensors and their mechanisms have been widely studied recently. In this paper, a broad but yet in-depth survey of current CNTs-based gas sensing technology is presented. Both experimental works and theoretical simulations are reviewed. The design, fabrication, and the sensing mechanisms of the CNTs-based gas sensors are discussed. The challenges and perspectives of the research are also addressed in this review.

  3. FEM assisted calibration of a MEMS-based dispensing system with integrated piezoresistive force sensors

    International Nuclear Information System (INIS)

    Lishchynska, Maryna; Leïchlé, Thierry; Nicu, Liviu

    2008-01-01

    The focus of this work is a liquid dispensing system relying on the use of piezoresistive silicon microcantilevers. The experimental calibration of newly developed devices, required for global characterization of their mechanical, electromechanical properties and other performance characteristics, is usually complicated due to the structures' small size as well as cost and time consumption. On the other hand, closed-form analytical solutions to the nonlinear behaviour of devices of non-canonical geometry incorporating residual stresses are not commonly available either. Therefore, virtual calibration by means of computational modelling and simulation is not only adequate but also highly desirable. The finite element method has repeatedly proven its worth as a useful and efficient technique for the investigation of various mechanical and multiphysical systems, and has been extensively used in the design and analysis of MEMS. In the present work, the method is employed for virtual calibration of mechanical and electromechanical properties of novel liquid dispensing cantilevers. Separately, mechanical and electromechanical simulation results are in good agreement with experiment. Combined, these simulation data provide the ultimate calibration tool, allowing control over the force applied by depositing devices onto the substrate, and thereby preventing stiction problems and damage of fragile depositing surfaces

  4. Theoretical prediction of experimental jump and pull-in dynamics in a MEMS sensor

    KAUST Repository

    Ruzziconi, Laura

    2014-09-15

    The present research study deals with an electrically actuated MEMS device. An experimental investigation is performed, via frequency sweeps in a neighbourhood of the first natural frequency. Resonant behavior is explored, with special attention devoted to jump and pull-in dynamics. A theoretical single degree-of-freedom spring-mass model is derived. Classical numerical simulations are observed to properly predict the main nonlinear features. Nevertheless, some discrepancies arise, which are particularly visible in the resonant branch. They mainly concern the practical range of existence of each attractor and the final outcome after its disappearance. These differences are likely due to disturbances, which are unavoidable in practice, but have not been included in the model. To take disturbances into account, in addition to the classical local investigations, we consider the global dynamics and explore the robustness of the obtained results by performing a dynamical integrity analysis. Our aim is that of developing an applicable confident estimate of the system response. Integrity profiles and integrity charts are built to detect the parameter range where reliability is practically strong and where it becomes weak. Integrity curves exactly follow the experimental data. They inform about the practical range of actuality. We discuss the combined use of integrity charts in the engineering design. Although we refer to a particular case-study, the approach is very general.

  5. Investigation of top electrode for PZT thick films based MEMS sensors

    DEFF Research Database (Denmark)

    Hindrichsen, Christian Carstensen; Pedersen, Thomas; Kristiansen, Paw T.

    2010-01-01

    In this work processing of screen printed piezoelectric PZT thick films on silicon substrates is investigated for use in future MEMS devices. E-beam evaporated Al and Pt are patterned on PZT as a top electrode using a lift-off process with a line width down to 3 mu m. Three test structures are used...... to investigate the optimal thickness of the top electrode, the degradation of the piezoelectric properties of the PZT film in absence of a diffusion barrier layer and finally how to fabricate electrical interconnects down the edge of the PZT thick film. The roughness of the PZT is found to have a strong...... influence on the conductance of the top electrode influencing the optimal top electrode thickness. A 100 nm thick top electrode on the PZT thick film with a surface roughness of 273 nm has a 4.5 times higher resistance compared to a similar wire on a planar SiO2 surface which has a surface roughness of less...

  6. MEMS Actuators for Improved Performance and Durability

    Science.gov (United States)

    Yearsley, James M.

    Micro-ElectroMechanical Systems (MEMS) devices take advantage of force-scaling at length scales smaller than a millimeter to sense and interact with directly with phenomena and targets at the microscale. MEMS sensors found in everyday devices like cell-phones and cars include accelerometers, gyros, pressure sensors, and magnetic sensors. MEMS actuators generally serve more application specific roles including micro- and nano-tweezers used for single cell manipulation, optical switching and alignment components, and micro combustion engines for high energy density power generation. MEMS rotary motors are actuators that translate an electric drive signal into rotational motion and can serve as rate calibration inputs for gyros, stages for optical components, mixing devices for micro-fluidics, etc. Existing rotary micromotors suffer from friction and wear issues that affect lifetime and performance. Attempts to alleviate friction effects include surface treatment, magnetic and electrostatic levitation, pressurized gas bearings, and micro-ball bearings. The present work demonstrates a droplet based liquid bearing supporting a rotary micromotor that improves the operating characteristics of MEMS rotary motors. The liquid bearing provides wear-free, low-friction, passive alignment between the rotor and stator. Droplets are positioned relative to the rotor and stator through patterned superhydrophobic and hydrophilic surface coatings. The liquid bearing consists of a central droplet that acts as the motor shaft, providing axial alignment between rotor and stator, and satellite droplets, analogous to ball-bearings, that provide tip and tilt stable operation. The liquid bearing friction performance is characterized through measurement of the rotational drag coefficient and minimum starting torque due to stiction and geometric effects. Bearing operational performance is further characterized by modeling and measuring stiffness, environmental survivability, and high

  7. Study and Evaluation of a PCB-MEMS Liquid Microflow Sensor

    Directory of Open Access Journals (Sweden)

    Grigoris Kaltsas

    2010-10-01

    Full Text Available This paper presents the evaluation of a miniature liquid microflow sensor, directly integrated on a PCB. The sensor operation is based on the convective heat transfer principle. The heating and sensing elements are thin Pt resistors which are in direct electrical contact with the external copper tracks of the printed circuit board. Due to the low thermal conductivity of the substrate material, a high degree of thermal isolation is obtained which improves the operating characteristics of the device. The sensor is able to operate under both the hot-wire and the calorimetric principle. In order to fully exploit the temperature distribution in the flowing liquid, multiple sensing elements are positioned in various distances from the heater. A special housing was developed which allowed implementation of the sensor into tubes of various cross sectional areas. The sensor sensitivity and measurement range as a function of the sensing element distance were quantified. A minimum resolution of 3 μL/min and a measurement flow range up to 500 μL/min were achieved.

  8. A Finite Element Model of a MEMS-based Surface Acoustic Wave Hydrogen Sensor

    Directory of Open Access Journals (Sweden)

    Walied A. Moussa

    2010-02-01

    Full Text Available Hydrogen plays a significant role in various industrial applications, but careful handling and continuous monitoring are crucial since it is explosive when mixed with air. Surface Acoustic Wave (SAW sensors provide desirable characteristics for hydrogen detection due to their small size, low fabrication cost, ease of integration and high sensitivity. In this paper a finite element model of a Surface Acoustic Wave sensor is developed using ANSYS12© and tested for hydrogen detection. The sensor consists of a YZ-lithium niobate substrate with interdigital electrodes (IDT patterned on the surface. A thin palladium (Pd film is added on the surface of the sensor due to its high affinity for hydrogen. With increased hydrogen absorption the palladium hydride structure undergoes a phase change due to the formation of the β-phase, which deteriorates the crystal structure. Therefore with increasing hydrogen concentration the stiffness and the density are significantly reduced. The values of the modulus of elasticity and the density at different hydrogen concentrations in palladium are utilized in the finite element model to determine the corresponding SAW sensor response. Results indicate that with increasing the hydrogen concentration the wave velocity decreases and the attenuation of the wave is reduced.

  9. Touch at a distance sensing: lateral-line inspired MEMS flow sensors

    International Nuclear Information System (INIS)

    Prakash Kottapalli, Ajay Giri; Asadnia, Mohsen; Miao, Jianmin; Triantafyllou, Michael

    2014-01-01

    Evolution bestowed the blind cavefish with a resourcefully designed lateral-line of sensors that play an essential role in many important tasks including object detection and avoidance, energy-efficient maneuvering, rheotaxis etc. Biologists identified the two types of vital sensors on the fish bodies called the superficial neuromasts and the canal neuromasts that are responsible for flow sensing and pressure-gradient sensing, respectively. In this work, we present the design, fabrication and experimental characterization of biomimetic polymer artificial superficial neuromast micro-sensor arrays. These biomimetic micro-sensors demonstrated a high sensitivity of 0.9 mV/(m s −1 ) and 0.022 V/(m s −1 ) and threshold velocity detection limits of 0.1 m s −1 and 0.015 m s −1 in determining air and water flows respectively. Experimental results demonstrate that the biological canal inspired polymer encapsulation on the array of artificial superficial neuromast sensors is capable of filtering steady-state flows that could otherwise significantly mask the relevant oscillatory flow signals of high importance. (paper)

  10. Experimental Study of the Information Signal of Combined Shock, Tilt, and Motion Sensor Based on the 3-Axis MEMS-Accelerometer

    Directory of Open Access Journals (Sweden)

    S. A. Vasyukov

    2014-01-01

    Full Text Available Modern car alarm systems are equipped with smart sensors implemented using various physical principles. These sensors have to ensure high reliability and validity of monitored parameters with a lack of false operations. First of all, shock sensor, which is a part of, essentially, entire alarm systems, as well as tilt and motion sensors are referred to the smart sensors.Shock sensors with the sensitive elements (SE of piezoelectric, microphone, and electromagnetic types possess a number of the essential shortcomings caused by the type of SE. It is, first of all, a narrow band of the sensitive elements, which does not allow true differentiation of shocks to the autobody from false actions, as well as a various sensitivity of sensors depending on the SE axis orientation.Tilt sensors of electromagnetic type implemented as separate devices were seldom used because of their high cost and imperfect characteristics. Though there is still a need for such sensors. The specified shortcomings can be hardly overcome through improvement of sensitive element hangers of considered sensors. The use of the three-axial accelerometers made by MEMS technology seems to be the most perspective here.The article presents results of pilot studies of the accelerations reached when auto-body is under shock and a car is inclined and runs. When measuring, the test board STM32F3DISCOVERY with the MEMS accelerometer LSM303DLHS is used. A level of noise and vibrations has been analysed when mounting a board on the plastic panel of the car and when operating the engine in the range from 700 to 4000 rpm. The article presents accelerations implemented under the following conditions: light shocks in different parts of the auto-body (wing, trunk, hood; strong shock (closing a door; slow and fast acceleration to the speed of 20 km/h with the subsequent braking and passage of obstacles such as "sleeping policemen".Research results enabled us to make justification for selecting the

  11. Method for lateral force calibration in atomic force microscope using MEMS microforce sensor.

    Science.gov (United States)

    Dziekoński, Cezary; Dera, Wojciech; Jarząbek, Dariusz M

    2017-11-01

    In this paper we present a simple and direct method for the lateral force calibration constant determination. Our procedure does not require any knowledge about material or geometrical parameters of an investigated cantilever. We apply a commercially available microforce sensor with advanced electronics for direct measurement of the friction force applied by the cantilever's tip to a flat surface of the microforce sensor measuring beam. Due to the third law of dynamics, the friction force of the equal value tilts the AFM cantilever. Therefore, torsional (lateral force) signal is compared with the signal from the microforce sensor and the lateral force calibration constant is determined. The method is easy to perform and could be widely used for the lateral force calibration constant determination in many types of atomic force microscopes. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Application of Surface Protective Coating to Enhance Environment-Withstanding Property of the MEMS 2D Wind Direction and Wind Speed Sensor

    Science.gov (United States)

    Shin, Kyu-Sik; Lee, Dae-Sung; Song, Sang-Woo; Jung, Jae Pil

    2017-01-01

    In this study, a microelectromechanical system (MEMS) two-dimensional (2D) wind direction and wind speed sensor consisting of a square heating source and four thermopiles was manufactured using the heat detection method. The heating source and thermopiles of the manufactured sensor must be exposed to air to detect wind speed and wind direction. Therefore, there are concerns that the sensor could be contaminated by deposition or adhesion of dust, sandy dust, snow, rain, and so forth, in the air, and that the membrane may be damaged by physical shock. Hence, there was a need to protect the heating source, thermopiles, and the membrane from environmental and physical shock. The upper protective coating to protect both the heating source and thermopiles and the lower protective coating to protect the membrane were formed by using high-molecular substances such as SU-8, Teflon and polyimide (PI). The sensor characteristics with the applied protective coatings were evaluated. PMID:28925942

  13. Application of Surface Protective Coating to Enhance Environment-Withstanding Property of the MEMS 2D Wind Direction and Wind Speed Sensor.

    Science.gov (United States)

    Shin, Kyu-Sik; Lee, Dae-Sung; Song, Sang-Woo; Jung, Jae Pil

    2017-09-19

    In this study, a microelectromechanical system (MEMS) two-dimensional (2D) wind direction and wind speed sensor consisting of a square heating source and four thermopiles was manufactured using the heat detection method. The heating source and thermopiles of the manufactured sensor must be exposed to air to detect wind speed and wind direction. Therefore, there are concerns that the sensor could be contaminated by deposition or adhesion of dust, sandy dust, snow, rain, and so forth, in the air, and that the membrane may be damaged by physical shock. Hence, there was a need to protect the heating source, thermopiles, and the membrane from environmental and physical shock. The upper protective coating to protect both the heating source and thermopiles and the lower protective coating to protect the membrane were formed by using high-molecular substances such as SU-8, Teflon and polyimide (PI). The sensor characteristics with the applied protective coatings were evaluated.

  14. Brassboard development of a MEMS-scanned ladar sensor for small ground robots

    Science.gov (United States)

    Stann, Barry L.; Dammann, John F.; Enke, Joseph A.; Jian, Pey-Schuan; Giza, Mark M.; Lawler, William B.; Powers, Michael A.

    2011-06-01

    The Army Research Laboratory (ARL) is researching a short-range ladar imager for navigation, obstacle/collision avoidance, and target detection/identification on small unmanned ground vehicles (UGV).To date, commercial UGV ladars have been flawed by one or more factors including low pixelization, insufficient range or range resolution, image artifacts, no daylight operation, large size, high power consumption, and high cost. ARL built a breadboard ladar based on a newly developed but commercially available micro-electro-mechanical system (MEMS) mirror coupled to a lowcost pulsed Erbium fiber laser transmitter that largely addresses these problems. Last year we integrated the ladar and associated control software on an iRobot PackBot and distributed the ladar imagery data via the PackBot's computer network. The un-tethered PackBot was driven through an indoor obstacle course while displaying the ladar data realtime on a remote laptop computer over a wireless link. We later conducted additional driving experiments in cluttered outdoor environments. This year ARL partnered with General Dynamics Robotics Systems to start construction of a brass board ladar design. This paper will discuss refinements and rebuild of the various subsystems including the transmitter and receiver module, the data acquisition and data processing board, and software that will lead to a more compact, lower cost, and better performing ladar. The current ladar breadboard has a 5-6 Hz frame rate, an image size of 256 (h) × 128 (v) pixels, a 60° × 30° field of regard, 20 m range, eyesafe operation, and 40 cm range resolution (with provisions for super-resolution or accuracy).

  15. Design, fabrication and characterization of a piezoelectric MEMS diaphragm resonator mass sensor

    International Nuclear Information System (INIS)

    Hu, Zhongxu; Hedley, John; Waugh, William; Gallacher, Barry; Keegan, Neil; Spoors, Julia; McNeil, Calum; Boillot, François-Xavier; Collet, Joël

    2013-01-01

    This work reports on the design, fabrication and characterization of a piezoelectrically actuated mass sensor. The sensor utilizes degenerate resonant modes in which one mode is used as a reference to compensate for environmental effects. The project builds on a capacitively driven version of the sensor allowing improvements and challenges surrounding the new design to be assessed in relation to modeling and fabrication. The operational mode of interest showed an average resonant frequency of 7.8 MHz (quality factor of 490), at atmospheric pressure with an electrically recovered signal to noise ratio of 2400:1. The lead zirconate titanate performance yielded a central displacement sensitivity of 1.50 nm V −1 , which is in good agreement with the levels predicted in modeling. A small initial split in the degenerate modes was recorded due to fabrication tolerances; however, the devices still exhibited good environmental stability, with a temperature sensitivity of only 11 Hz °C −1 . Electroplating of gold onto the sensor surface demonstrated a device mass sensitivity of 12.0 Hz pg −1 . (paper)

  16. All-Optical Frequency Modulated High Pressure MEMS Sensor for Remote and Distributed Sensing

    DEFF Research Database (Denmark)

    Reck, Kasper; Thomsen, Erik Vilain; Hansen, Ole

    2011-01-01

    We present the design, fabrication and characterization of a new all-optical frequency modulated pressure sensor. Using the tangential strain in a circular membrane, a waveguide with an integrated nanoscale Bragg grating is strained longitudinally proportional to the applied pressure causing a sh...

  17. A Thermal displacement sensor in MEMS [Towards accurate small-scale manipulation

    NARCIS (Netherlands)

    Krijnen, Bram; Krijnen, B.; Hogervorst, Richard; Dijkstra, Jan Willem; Engelen, Johannes Bernardus Charles; Woldering, L.A.; Brouwer, Dannis Michel; Abelmann, Leon; Soemers, Herman

    Accurate manipulation of small objects is becoming more and more important. Besides accurate manipulation, the demand for small manipulators is also increasing. Some examples are high-density data storage, (digital) light processing, accelerometers, rate sensors, and the use of cantilevers in atomic

  18. Fabrication of mechano-optical sensors for hydrogen gas

    NARCIS (Netherlands)

    Pham Van So, P.V.S.; Kauppinen, L.J.; Dijkstra, Mindert; van Wolferen, Hendricus A.G.M.; de Ridder, R.M.; Hoekstra, Hugo

    2009-01-01

    We present results related to the fabrication of a novel and highly sensitive mechano-optical sensor for hydrogen gas, based on microcantilevers, supplied with a selective gas absorbing layer (Pd), suspended above a Si3N4 grated waveguide (GWG). Integrated microcantilever-GWG devices have been

  19. A Miniaturized Optical Sensor with Integrated Gas Cell

    NARCIS (Netherlands)

    Ayerden, N.P.; Ghaderi, M.; De Graaf, G.; Wolffenbuttel, R.F.

    2015-01-01

    The design, fabrication and characterization of a highly integrated optical gas sensor is presented. The gas cell takes up most of the space in a microspectrometer and is the only component that has so far not been miniaturized. Using the tapered resonator cavity of a linear variable optical filter

  20. Corroles-Porphyrins: A Teamwork for Gas Sensor Arrays

    Directory of Open Access Journals (Sweden)

    Rosamaria Capuano

    2015-04-01

    Full Text Available Porphyrins provide an excellent material for chemical sensors, and they have been used for sensing species both in air and solution. In the gas phase, the broad selectivity of porphyrins is largely dependant on molecular features, such as the metal ion complexed at the core of the aromatic ring and the peripheral substituents. Although these features have been largely exploited to design gas sensor arrays, so far, little attention has been devoted to modify the sensing properties of these macrocycles by variation of the molecular aromatic ring. In this paper, the gas sensing properties of a porphyrin analog, the corrole, are studied in comparison with those of the parent porphyrin. Results show that changes in the aromatic ring have important consequences on the sensitivity and selectivity of the sensors and that porphyrins and corroles can positively cooperate to enhance the performance of sensor arrays.

  1. Corroles-porphyrins: a teamwork for gas sensor arrays.

    Science.gov (United States)

    Capuano, Rosamaria; Pomarico, Giuseppe; Paolesse, Roberto; Di Natale, Corrado

    2015-04-08

    Porphyrins provide an excellent material for chemical sensors, and they have been used for sensing species both in air and solution. In the gas phase, the broad selectivity of porphyrins is largely dependant on molecular features, such as the metal ion complexed at the core of the aromatic ring and the peripheral substituents. Although these features have been largely exploited to design gas sensor arrays, so far, little attention has been devoted to modify the sensing properties of these macrocycles by variation of the molecular aromatic ring. In this paper, the gas sensing properties of a porphyrin analog, the corrole, are studied in comparison with those of the parent porphyrin. Results show that changes in the aromatic ring have important consequences on the sensitivity and selectivity of the sensors and that porphyrins and corroles can positively cooperate to enhance the performance of sensor arrays.

  2. In-situ, Real-Time Monitoring of Mechanical and Chemical Structure Changes in a V2O5 Battery Electrode Using a MEMS Optical Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Jung, H. [University of Maryland; Gerasopoulos, K. [University of Maryland; Gnerlich, Markus [University of Maryland; Talin, A. Alec [Sandia National Laboratories; Ghodssi, Reza [University of Maryland

    2014-06-01

    This work presents the first demonstration of a MEMS optical sensor for in-situ, real-time monitoring of both mechanical and chemical structure evolutions in a V2O5 lithium-ion battery (LIB) cathode during battery operation. A reflective membrane forms one side of a Fabry-Perot (FP) interferometer, while the other side is coated with V2O5 and exposed to electrolyte in a half-cell LIB. Using one microscope and two laser sources, both the induced membrane deflection and the corresponding Raman intensity changes are observed during lithium cycling. Results are in good agreement with the expected mechanical behavior and disorder change of the V2O5 layers, highlighting the significant potential of MEMS as enabling tools for advanced scientific investigations.

  3. A miniaturized optical gas sensor for natural gas analysis

    NARCIS (Netherlands)

    Ayerden, N.P.

    2016-01-01

    The depletion of domestic reserves and the growing use of sustainable resources forces a transition from the locally produced natural gas with a well-known composition toward the ‘new’ gas with a more flexible composition in the Netherlands. For safe combustion and proper billing, the natural gas

  4. Design of Wireless Readout System for Resonant Gas Sensors

    OpenAIRE

    S. Mohamed Rabeek; Mi Kyoung Park; M. Annamalai Arasu

    2016-01-01

    This paper presents a design of a wireless read out system for tracking the frequency shift of the polymer coated piezoelectric micro electromechanical resonator due to gas absorption. The measure of this frequency shift indicates the percentage of a particular gas the sensor is exposed to. It is measured using an oscillator and an FPGA based frequency counter by employing the resonator as a frequency determining element in the oscillator. This system consists of a Gas Sensing Wireless Readou...

  5. Cost-effective MEMS piezoresistive cantilever-based sensor fabrication for gait movement analysis

    Science.gov (United States)

    Saadon, Salem; Anuar, A. F. M.; Wahab, Yufridin

    2017-03-01

    The conventional photolithography of crystalline silicon technique is limited to two-dimensional and structure scaling. It's also requiring a lot of time and chemical involves for the whole process. These problems can be overcome by using laser micromachining technique, that capable to produce three-dimensional structure and simultaneously avoiding the photo mask needs. In this paper, we reported on the RapidX-250 Excimer laser micromachining with 248 nm KrF to create in-time mask design and assisting in the fabrication process of piezo-resistive micro cantilever structures. Firstly, laser micromachining parameters have been investigated in order to fabricate the acceleration sensor to analyzing human gait movement. Preliminary result shows that the fabricated sensor able to define the movement difference of human motion regarding the electrical characteristic of piezo-resistor.

  6. Full thermoelectric characterization of InAs nanowires using MEMS heater/sensors.

    Science.gov (United States)

    Karg, S F; Troncale, V; Drechsler, U; Mensch, P; Das Kanungo, P; Schmid, H; Schmidt, V; Gignac, L; Riel, H; Gotsmann, B

    2014-08-01

    Precise measurements of a complete set of thermoelectric parameters on a single indium-arsenide nanowire (NW) have been performed using highly sensitive, micro-fabricated sensing devices based on the heater/sensor principle. The devices were fabricated as micro electro-mechanical systems consisting of silicon nitride membranes structured with resistive gold heaters/sensors. Preparation, operation and characterization of the devices are described in detail. Thermal decoupling of the heater/sensor platforms has been optimized reaching thermal conductances as low as 20 nW K(-1) with a measurements sensitivity below 20 nW K(-1). The InAs NWs were characterized in terms of thermal conductance, four-probe electrical conductance and thermopower (Seebeck coefficient), all measured on a single NW. The temperature dependence of the parameters determining the thermoelectric figure-of-merit of an InAs NW was acquired in the range 200-350 K featuring a minor decrease of the thermal conductivity from 2.7 W (m K)(-1) to 2.3 W (m K)(-1).

  7. Solid-state titania-based gas sensor for liquefied petroleum gas ...

    Indian Academy of Sciences (India)

    Solid-state titania-based gas sensor for liquefied petroleum gas detection at room temperature. B C Yadav ... This paper reports the liquefied petroleum gas (LPG) sensing of titanium dioxide (Qualigens, India). Scanning electron ... Variations in resistance with exposure of LPG to the sensing element were observed.

  8. The Capacitance and Temperature Effects of the SiC- and Si-Based MEMS Pressure Sensor

    International Nuclear Information System (INIS)

    Marsi, N; Majlis, B Y; Hamzah, A A; Mohd, F

    2013-01-01

    This project develops the pressure sensor for monitoring the extreme conditions inside the gas turbine engine. The capacitive-based instead of piezoresistive-based pressure sensor is employed to avoid temperature drift. The deflecting (top) plate and the fixed (bottom) plate generate the capacitance, which is proportional to the applied input pressure and temperature. Two thin film materials of four different sizes are employed for the top plate, namely cubic silicon carbide (3C-SiC) and silicon (Si). Their performances in term of the sensitivity and linearity of the capacitance versus pressure are simulated at the temperature of 27°C, 500°C, 700°C and 1000°C. The results show that both materials display linear characteristics for temperature up to 500°C, although SiC-based sensor shows higher sensitivity. However, when the temperatures are increased to 700°C and 1000°C, the Si- based pressure sensor starts to malfunction at 50 MPa. However, the SiC-based pressure sensor continues to demonstrate high sensitivity and linearity at such high temperature and pressure. This paper validates the need of employing silicon carbide instead of silicon for sensing of extreme environments.

  9. MEMS packaging

    CERN Document Server

    Hsu , Tai-Ran

    2004-01-01

    MEMS Packaging discusses the prevalent practices and enabling techniques in assembly, packaging and testing of microelectromechanical systems (MEMS). The entire spectrum of assembly, packaging and testing of MEMS and microsystems, from essential enabling technologies to applications in key industries of life sciences, telecommunications and aerospace engineering is covered. Other topics included are bonding and sealing of microcomponents, process flow of MEMS and microsystems packaging, automated microassembly, and testing and design for testing.The Institution of Engineering and Technology is

  10. Carbon Nanotube Gas Sensor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Sensing gas molecules is critical to environmental monitoring, control of chemical processes, space missions as well as agricultural and medical applications....

  11. Gas Sensors Based on Semiconducting Nanowire Field-Effect Transistors

    Directory of Open Access Journals (Sweden)

    Ping Feng

    2014-09-01

    Full Text Available One-dimensional semiconductor nanostructures are unique sensing materials for the fabrication of gas sensors. In this article, gas sensors based on semiconducting nanowire field-effect transistors (FETs are comprehensively reviewed. Individual nanowires or nanowire network films are usually used as the active detecting channels. In these sensors, a third electrode, which serves as the gate, is used to tune the carrier concentration of the nanowires to realize better sensing performance, including sensitivity, selectivity and response time, etc. The FET parameters can be modulated by the presence of the target gases and their change relate closely to the type and concentration of the gas molecules. In addition, extra controls such as metal decoration, local heating and light irradiation can be combined with the gate electrode to tune the nanowire channel and realize more effective gas sensing. With the help of micro-fabrication techniques, these sensors can be integrated into smart systems. Finally, some challenges for the future investigation and application of nanowire field-effect gas sensors are discussed.

  12. Enhanced polymeric encapsulation for MEMS based multi sensors for fisheries research

    DEFF Research Database (Denmark)

    Birkelund, Karen; Nørgaard, Lars; Thomsen, Erik Vilain

    2011-01-01

    light intensity, temperature, pressure and conductivity. For precise and fast measurements a direct exposure of the sensor to the water is desirable. A potted tube encapsulation concept has shown to be promising for accurate and fast measurements in harsh environment, provided a tight sealing...... of the electronics can be made. In this paper we investigate the interfacial delamination of an epoxy encapsulated chip. Differently prepared silicon chips are investigated and it is found that silicon dioxide surfaces functionalised with (3-aminopropyl) triethoxysilane will improve this encapsulation approach...

  13. Monitoring of slope-instabilities and deformations with Micro-Electro-Mechanical-Systems (MEMS) in wireless ad-hoc Sensor Networks

    Science.gov (United States)

    Arnhardt, C.; Fernández-Steeger, T. M.; Azzam, R.

    2009-04-01

    In most mountainous regions, landslides represent a major threat to human life, properties and infrastructures. Nowadays existing landslide monitoring systems are often characterized by high efforts in terms of purchase, installation, maintenance, manpower and material. In addition (or because of this) only small areas or selective points of the endangered zone can be observed by the system. Therefore the improvement of existing and the development of new monitoring and warning systems are of high relevance. The joint project "Sensor based Landslide Early Warning Systems" (SLEWS) deals with the development of a prototypic Alarm- and Early Warning system (EWS) for different types of landslides using low-cost micro-sensors (MEMS) integrated in a wireless sensor network (WSN). Modern so called Ad-Hoc, Multi-Hop wireless sensor networks (WSN) are characterized by a self organizing and self-healing capacity of the system (autonomous systems). The network consists of numerous individual and own energy-supply operating sensor nodes, that can send data packages from their measuring devices (here: MEMS) over other nodes (Multi-Hop) to a collection point (gateway). The gateway provides the interface to central processing and data retrieval units (PC, Laptop or server) outside the network. In order to detect and monitor the different landslide processes (like fall, topple, spreading or sliding) 3D MEMS capacitive sensors made from single silicon crystals and glass were chosen to measure acceleration, tilting and altitude changes. Based on the so called MEMS (Micro-Electro-Mechanical Systems) technology, the sensors combine very small mechanical and electronic units, sensing elements and transducers on a small microchip. The mass production of such type of sensors allows low cost applications in different areas (like automobile industries, medicine, and automation technology). Apart from the small and so space saving size and the low costs another advantage is the energy

  14. Development of a hydrogen gas sensor using microfabrication technology

    Science.gov (United States)

    Liu, Chung-Chiun; Wu, Qinghai; Stuczynski, Matthew; Madzsar, George C.

    1992-01-01

    Microfabrication and micromachining technologies are used to produce a hydrogen gas sensor based on a palladium-silver film. The sensor uses a heater that is fabricated by diffusing p-type borones into the substrate, forming a resistance heater. A diode for temperature measurement is produced using p-type boron and n-type phosphor diffused into the substrate. A thickness of the palladium-silver film is approximately 300 arcsec. The hydrogen gas sensor employs the proven palladium-silver diode structure and is surrounded by a phosphor doped resistance heater which can be heated up to a temperature of 250 C. Experimental results show that the sensor is capable of operating over a wide range of hydrogen concentration levels between 0-95 percent without any hysteresis effects.

  15. Recent progress in carbon nanotube-based gas sensors

    International Nuclear Information System (INIS)

    Zhang Ting; Mubeen, Syed; Myung, Nosang V; Deshusses, Marc A

    2008-01-01

    The development of carbon nanotube-(CNTs-)based gas sensors and sensor arrays has attracted intensive research interest in the last several years because of their potential for the selective and rapid detection of various gaseous species by novel nanostructures integrated in miniature and low-power consuming electronics. Chemiresistors and chemical field effect transistors are probably the most promising types of gas nanosensors. In these sensors, the electrical properties of nanostructures are dramatically changed when exposed to the target gas analytes. In this review, recent progress on the development of different types of CNT-based nanosensors is summarized. The focus was placed on the means used by various researchers to improve the sensing performance (sensitivity, selectivity and response time) through the rational functionalization of CNTs with different methods (covalent and non-covalent) and with different materials (polymers and metals). (topical review)

  16. SiC flame sensors for gas turbine control systems

    Science.gov (United States)

    Brown, Dale M.; Downey, Evan; Kretchmer, Jim; Michon, Gerald; Emily Shu; Schneider, Don

    1998-05-01

    The research and development activities carried out to develop a SiC flame sensor for gas turbines utilized for power generation are discussed. These activities included the fabrication and characterization of SiC UV photodiodes and small SiC signal diodes as well as the designing and testing of production flame detector assemblies. The characteristics that make this solid state flame detector particularly useful for dry low NO x (DLN) premixed oil and natural gas fuels will be described. Since this device provides both analog dc and ac output signals, turbine combustor mode tracking, combustion flame dynamics and flame intensity tracking have been demonstrated. Sensors designed for production have been built, qualified and field tested. These sensors are now being installed in gas turbine power plants and are a component part of the turbine control system. This development has resulted in the first commercialized turbine control application to use SiC electronic devices.

  17. Sensors for online determination of CNG gas quality; Sensorer foer onlinebestaemnning av fordonsgaskvalitet

    Energy Technology Data Exchange (ETDEWEB)

    Stenlaaaas, Ola; Roedjegaard, Henrik

    2012-07-01

    Swedish automotive gas has until now been a very uniform, high quality automotive fuel. Elsewhere in Europe the quality of automotive gas varies significantly. Gas from different sources with different flammability require engine settings adjusted to the chosen gas' unique composition. The prospects for a vehicle-mounted sensor based on infrared technology for gas quality measurement has been studied and solutions are presented with questions that must be answered in a possible future work. The proposed vehicle mounted sensor is based on two channels, one of which measures the partial pressure of methane and the other measures the partial pressure of heavier hydrocarbons in 'equivalents of butane'. Ethane produces a signal of about 0.6 equivalents of butane and propane about 0.8 equivalents. The sensor can be accommodated in a cube with 5 cm side and should be equipped with nipple connections to the existing system. The sensor is expected to work throughout their entire lifetime without manual calibration, through continuous automatic calibration, so-called ABC (Automatic Baseline Compensation). The sensor will have to meet tough quality and environmental standards in which primarily contact ring, vibration and prevention of leakage are identified as extra difficult. Working temperatures and the electrical conditions of power supply and communication interface is considered less challenging. In one million volumes, the cost per sensor could be 200 to 300 SEK.

  18. Mass and position determination in MEMS mass sensors: a theoretical and an experimental investigation

    KAUST Repository

    Bouchaala, Adam M.

    2016-08-31

    We present a method to determine accurately the position and mass of an entity attached to the surface of an electrostatically actuated clamped-clamped microbeam implemented as a mass sensor. In the theoretical investigation, the microbeam is modeled as a nonlinear Euler-Bernoulli beam and a perturbation technique is used to develop a closed-form expression for the frequency shift due to an added mass at a specific location on the microbeam surface. The experimental investigation was conducted on a microbeam made of Polyimide with a special lower electrode to excite both of the first and second modes of vibration. Using an ink-jet printer, we deposited droplets of polymers with a defined mass and position on the surface of the microbeam and we measured the shifts in its resonance frequencies. The theoretical predictions of the mass and position of the deposited droplets match well with the experimental measurements.

  19. Mass and Position Determination in MEMS Resonant Mass Sensors: Theoretical and Experimental Investigation

    KAUST Repository

    Bouchaala, Adam M.

    2016-12-05

    We present a method to determine accurately the position and mass of an entity attached to the surface of an electrostatically actuated clamped-clamped microbeam implemented as a mass sensor. In the theoretical investigation, the microbeam is modeled as a nonlinear Euler-Bernoulli beam and a perturbation technique is used to develop a closed-form expression for the frequency shift due to an added mass at a specific location on the microbeam surface. The experimental investigation was conducted on a microbeam made of Polyimide with a special lower electrode to excite both of the first and second modes of vibration. Using an ink-jet printer, we deposited droplets of polymers with a defined mass and position on the surface of the microbeam and we measured the shifts in its resonance frequencies. The theoretical predictions of the mass and position of the deposited droplets match well with the experimental measurements.

  20. Solid-State Gas Sensors: Sensor System Challenges in the Civil Security Domain

    Directory of Open Access Journals (Sweden)

    Gerhard Müller

    2016-01-01

    Full Text Available The detection of military high explosives and illicit drugs presents problems of paramount importance in the fields of counter terrorism and criminal investigation. Effectively dealing with such threats requires hand-portable, mobile and affordable instruments. The paper shows that solid-state gas sensors can contribute to the development of such instruments provided the sensors are incorporated into integrated sensor systems, which acquire the target substances in the form of particle residue from suspect objects and which process the collected residue through a sequence of particle sampling, solid-vapor conversion, vapor detection and signal treatment steps. Considering sensor systems with metal oxide gas sensors at the backend, it is demonstrated that significant gains in sensitivity, selectivity and speed of response can be attained when the threat substances are sampled in particle as opposed to vapor form.

  1. Design and application of a metal wet-etching post-process for the improvement of CMOS-MEMS capacitive sensors

    International Nuclear Information System (INIS)

    Tsai, Ming-Han; Sun, Chih-Ming; Liu, Yu-Chia; Fang, Weileun; Wang, Chuanwei

    2009-01-01

    This study presents a process design methodology to improve the performance of a CMOS-MEMS gap-closing capacitive sensor. In addition to the standard CMOS process, the metal wet-etching approach is employed as the post-CMOS process to realize the present design. The dielectric layers of the CMOS process are exploited to form the main micro mechanical structures of the sensor. The metal layers of the CMOS process are used as the sensing electrodes and sacrificial layers. The advantages of the sensor design are as follows: (1) the parasitic capacitance is significantly reduced by the dielectric structure, (2) in-plane and out-of-plane sensing gaps can be reduced to increase the sensitivity, and (3) plate-type instead of comb-type out-of-plane sensing electrodes are available to increase the sensing electrode area. To demonstrate the feasibility of the present design, a three-axis capacitive CMOS-MEMS accelerometers chip is implemented and characterized. Measurements show that the sensitivities of accelerometers reach 11.5 mV G −1 (in the X-, Y-axes) and 7.8 mV G −1 (in the Z-axis), respectively, which are nearly one order larger than existing designs. Moreover, the detection of 10 mG excitation using the three-axis accelerometer is demonstrated for both in-plane and out-of-plane directions

  2. Chemical sensors and gas sensors for process control in biotechnology

    International Nuclear Information System (INIS)

    Williams, D.E.

    1988-04-01

    This paper is concerned with the possibilities for chemical measurement of the progress of biotechnological processes which are offered by devices already developed for other demanding applications. It considers the potential use of ultrasonic instrumentation originally developed for the nuclear industry, gas measurement methods from the fields of environmental monitoring and combustion control, nuclear instruments developed for the oil, mining and chemical industries, robotic systems and advanced control techniques. (author)

  3. Towards Enhanced Gas Sensor Performance with Fluoropolymer Membranes

    Directory of Open Access Journals (Sweden)

    Thorsten Graunke

    2016-09-01

    Full Text Available In this paper we report on how to increase the selectivity of gas sensors by using fluoropolymer membranes. The mass transport of polar and non-polar gases through a polymer membrane matrix was studied by systematic selection of polymers with different degrees of fluorination, as well as polymers whose monomers have ether groups (-O- in addition to fluorine groups (-F. For the study, a set of application-relevant gases including H2, CO, CO2, NO2, methane, ethanol, acetone, and acetaldehyde as well as various concentrations of relative humidity were used. These gases have different functional groups and polarities, yet have a similar kinetic diameter and are therefore typically difficult to separate. The concentrations of the gases were chosen according to international indicative limit values (TWA, STEL. To measure the concentration in the feed and permeate, we used tin-dioxide-based metal oxide gas sensors with palladium catalyst (SnO2:Pd, catalytic sensors (also SnO2:Pd-based and thermal conductivity sensors. This allows a close examination of the interdependence of diffusion and physicochemical operating principle of the sensor. Our goal is to increase the selectivity of gas sensors by using inexpensive fluoropolymer membranes. The measurements showed that through membranes with low polarity, preferably non-polar gases are transported. Furthermore, the degree of crystallization influences the permeability and selectivity of a polymer membrane. Basically the polar polymers showed a higher permeability to water vapor and polar substances than non-polar polymer membranes.

  4. Early detection of LPG gas leakage based Wireless Sensor Networking

    Directory of Open Access Journals (Sweden)

    Kusriyanto Medilla

    2018-01-01

    Full Text Available LPG gas is the main fuel used in households. These days LPG gas leak triggered an accident that resulted in huge losses, especially if the accident occurred within the dense housing. LPG gas leakage monitoring and early detection of a gas leak and a leak warning is needed to prevent more fatal accident. Wireless sensor networking is a technology that can be used to build a centralized monitoring system by using a microcontroller as the interface and control system. This research developed system device monitoring and early detection of gas leaks by utilizing gas sensors MQ-4 and AVR microcontroller family as control devices. The system is also equipped with XBee PRO S2B nirkable devices as the interface to the wireless networking system that is used to transmit sensor data from the detection point to the monitoring center equipped with a PC and software integrated Visual Basic. Gas leak alert is sent with the message formats through social networking Gtalk.

  5. MEMS Solar Generators

    OpenAIRE

    Grbovic, Dragoslav; Osswald, Sebastian

    2011-01-01

    Approved for public release; distribution is unlimited Using MEMS bimaterial structures to build highly efficient solar energy generators. This is a novel approach that utilizes developments in the area of bimaterial sensors and applies them in the field of solar energy harvesting.

  6. Design of micro-sensor-array detector for toxic gas

    Science.gov (United States)

    Liao, Hai-yang; Tian, Peng

    2010-08-01

    To quickly measure the trace concentration of the single component toxic gas (e.g. sarin), a micro-array toxic gas detector is designed. A 3 x 3 gas sensor array with metalloporphyrins as sensitive materials is introduced. A micro-capsule that can be easy to be loaded and unloaded is designed for the gas reaction. A fiber-array optical path is designed, which is based on the principle that gas sensors will show different colors after reaction with the toxic gas. The tricolor information about the concentration of gas is collected by the color liner CCD. A control handling system with C8051F021 MCU as the core is implemented and embedded into the detector to perform the functions of gas sampling, data collection and analysis calculation. Data acquisition experimental results show that the proposed scheme can effectively collect the color information after gas reaction. Moreover, the system has many important advantages, such as small size, compact structure, high degree of automation, fast detection speed and high performance-cost ratio, etc.

  7. Organic field-effect transistor-based gas sensors.

    Science.gov (United States)

    Zhang, Congcong; Chen, Penglei; Hu, Wenping

    2015-04-21

    Organic field-effect transistors (OFETs) are one of the key components of modern organic electronics. While the past several decades have witnessed huge successes in high-performance OFETs, their sophisticated functionalization with regard to the responses towards external stimulations has also aroused increasing attention and become an important field of general concern. This is promoted by the inherent merits of organic semiconductors, including considerable variety in molecular design, low cost, light weight, mechanical flexibility, and solution processability, as well as by the intrinsic advantages of OFETs including multiparameter accessibility and ease of large-scale manufacturing, which provide OFETs with great potential as portable yet reliable sensors offering high sensitivity, selectivity, and expeditious responses. With special emphases on the works achieved since 2009, this tutorial review focuses on OFET-based gas sensors. The working principles of this type of gas sensors are discussed in detail, the state-of-the-art protocols developed for high-performance gas sensing are highlighted, and the advanced gas discrimination systems in terms of sensory arrays of OFETs are also introduced. This tutorial review intends to provide readers with a deep understanding for the future design of high-quality OFET gas sensors for potential uses.

  8. Indoor air quality inspection and analysis system based on gas sensor array

    Science.gov (United States)

    Gao, Xiang; Wang, Mingjiang; Fan, Binwen

    2017-08-01

    A detection and analysis system capable of measuring the concentration of four major gases in indoor air is designed. It uses four gas sensors constitute a gas sensor array, to achieve four indoor gas concentration detection, while the detection of data for further processing to reduce the cross-sensitivity between the gas sensor to improve the accuracy of detection.

  9. Cellular dynamics of bovine aortic smooth muscle cells measured using MEMS force sensors

    Science.gov (United States)

    Tsukagoshi, Takuya; Nguyen, Thanh-Vinh; Hirayama Shoji, Kayoko; Takahashi, Hidetoshi; Matsumoto, Kiyoshi; Shimoyama, Isao

    2018-04-01

    Adhesive cells perceive the mechanical properties of the substrates to which they adhere, adjusting their cellular mechanical forces according to their biological characteristics. This mechanical interaction subsequently affects the growth, locomotion, and differentiation of the cell. However, little is known about the detailed mechanism that underlies this interaction between adherent cells and substrates because dynamically measuring mechanical phenomena is difficult. Here, we utilize microelectromechamical systems force sensors that can measure cellular traction forces with high temporal resolution (~2.5 µs) over long periods (~3 h). We found that the cellular dynamics reflected physical phenomena with time scales from milliseconds to hours, which contradicts the idea that cellular motion is slow. A single focal adhesion (FA) generates an average force of 7 nN, which disappears in ms via the action of trypsin-ethylenediaminetetraacetic acid. The force-changing rate obtained from our measurements suggests that the time required for an FA to decompose was nearly proportional to the force acting on the FA.

  10. WGP structures patterned by Lloyd's mirror laser interference lithography system integrate into MEMS physical sensor device

    Science.gov (United States)

    Tseng, Kuo-Chun; Hong, Shuo-Ting; Lin, Te-Hsun; Chuang, Tzu-Han; Fu, Chien-Chung

    2016-03-01

    Wire-grid polarizers (WGPs) are composed of 1-D nanoscale periodic structures and are widely used in liquid crystal display devices to enhance the brightness and improve the utilization rate of the backlight source. This paper proposes the design and application of a WGP device for an microelectromechanical system physical force sensor derived through an optical measurement method. Infrared (IR) light was served as the signal source, with the initial angle set incident to the WGP, which was fabricated on microstructures such as cantilever beam, thin-film or bridge structures. According to the operation principle, when a physical force affects the microstructures, the incident angle of the signal light changes, which easily produces different transmission signal values for detection by an IR photodetector. Therefore, the proposed system can be used for optical contactless sensing in physical force sensing modules. Furthermore, the WGP structure introduced in this paper was defined using laser interference lithography and deposited with Al by E-beam evaporation.

  11. Platform for a Hydrocarbon Exhaust Gas Sensor Utilizing a Pumping Cell and a Conductometric Sensor

    Directory of Open Access Journals (Sweden)

    Ralf Moos

    2009-09-01

    Full Text Available Very often, high-temperature operated gas sensors are cross-sensitive to oxygen and/or they cannot be operated in oxygen-deficient (rich atmospheres. For instance, some metal oxides like Ga2O3 or doped SrTiO3 are excellent materials for conductometric hydrocarbon detection in the rough atmosphere of automotive exhausts, but have to be operated preferably at a constant oxygen concentration. We propose a modular sensor platform that combines a conductometric two-sensor-setup with an electrochemical pumping cell made of YSZ to establish a constant oxygen concentration in the ambient of the conductometric sensor film. In this paper, the platform is introduced, the two-sensor-setup is integrated into this new design, and sensing performance is characterized. Such a platform can be used for other sensor principles as well.

  12. Nanoparticle-based gas sensors and methods of using the same

    Energy Technology Data Exchange (ETDEWEB)

    Mickelson, William; Zettl, Alex

    2017-10-17

    Gas sensors are provided. The gas sensors include a gas sensing element having metal oxide nanoparticles and a thin-film heating element. Systems that include the gas sensors, as well as methods of using the gas sensors, are also provided. Embodiments of the present disclosure find use in a variety of different applications, including detecting whether an analyte is present in a gaseous sample.

  13. ZnO Coated Nanospring-Based Gas Sensors

    Science.gov (United States)

    Bakharev, Pavel Viktorovich

    The current research demonstrates new techniques for characterization of electrical transport properties of the metal oxide polycrystalline structures, gas and vapor phase kinetics, surface processes such as gas-surface, vapor-surface interactions and redox processes by applying novel gas sensing devices. Real-time sensor electrical response characteristics obtained under highly controlled laboratory conditions have been used to characterize corresponding surface interactions and electrical properties of the gas sensitive structures. Novel redox chemical sensors (chemiresistors) have been fabricated with 3-D and 1-D ZnO coated nanospring (NS) structures. Silica NSs served as insulating scaffolding for a ZnO gas sensitive layer and has been grown via a vapor-liquid-solid (VLS) mechanism by using a chemical vapor deposition (CVD) technique. The NSs have been coated with polycrystalline ZnO by atomic layer deposition (ALD). The chemiresistor devices have been thoroughly characterized in terms of their crystal structures (by XRD, FESEM, TEM, and ellipsometry) and their electrical response properties. A 3-D gas sensor has been constructed from a xenon light bulb by coating it with a 3-D zinc oxide coated silica nanospring mat, where the xenon light bulb served as a sensor heater. This inexpensive sensor platform has been used to characterize gas-solid, vapor-solid, and redox processes. The optimal temperature of the gas sensitive ZnO layer, the temperature of the vapor-gas mixture and the crystal structure of the gas sensitive layer have been determined to reach the highest sensitivity of the gas sensors. The activation energy of toluene oxidation (Ed) on the ZnO surface and the activation energy of oxidation (Ea) of the depleted ZnO surface have been determined and analyzed. A 1-D chemiresistor has been fabricated with a single ZnO coated silica nanospring by photolithography. The question of sensor sensitivity of MOS nanomaterials and MOS thin films has been addressed

  14. Low-power-Consumption metal oxide NO2 gas sensor based on micro-heater and screen printing technology.

    Science.gov (United States)

    Moon, S E; Lee, H K; Choi, N J; Lee, J; Yang, W S; Kim, J; Jong, J J; Yoo, D J

    2012-07-01

    An NO2 micro gas sensor was fabricated based on a micro-heater using tin oxide nano-powders for effective gas detection and monitoring system with low power consumption and high sensitivity. The processes of the fabrication were acceptable to the conventional CMOS processes for mass-production. Semiconducting SnO2 nano-powders were synthesized via the co-precipitation method; and to increase the sensitivity of the NO2 gas rare metal dopants were added. In the structure of the micro-heater, the resistances of two semi-circular Pt heaters were connected to the spreader for thermal uniformity. The resistance of each heater becomes an electrically equal Wheatstone-bridge, which was divided in half by the heat spreading structure. Based on the aforementioned design, a low-power-consumption micro-heater was fabricated using the CMOS-compatible MEMS processes. A bridge-type micro-heater based on the Si substrate was fabricated via surface micro-machining. The NO2 sensing properties of a screen-printed tin oxide thick film device were measured The micro gas sensors showed substantial sensitivity down to 0.5 ppm NO2 at a low power consumption (34.2 mW).

  15. Optimized Feature Extraction for Temperature-Modulated Gas Sensors

    Directory of Open Access Journals (Sweden)

    Alexander Vergara

    2009-01-01

    Full Text Available One of the most serious limitations to the practical utilization of solid-state gas sensors is the drift of their signal. Even if drift is rooted in the chemical and physical processes occurring in the sensor, improved signal processing is generally considered as a methodology to increase sensors stability. Several studies evidenced the augmented stability of time variable signals elicited by the modulation of either the gas concentration or the operating temperature. Furthermore, when time-variable signals are used, the extraction of features can be accomplished in shorter time with respect to the time necessary to calculate the usual features defined in steady-state conditions. In this paper, we discuss the stability properties of distinct dynamic features using an array of metal oxide semiconductors gas sensors whose working temperature is modulated with optimized multisinusoidal signals. Experiments were aimed at measuring the dispersion of sensors features in repeated sequences of a limited number of experimental conditions. Results evidenced that the features extracted during the temperature modulation reduce the multidimensional data dispersion among repeated measurements. In particular, the Energy Signal Vector provided an almost constant classification rate along the time with respect to the temperature modulation.

  16. Improved zinc oxide film for gas sensor applications

    Indian Academy of Sciences (India)

    Zinc oxide (ZnO) is a versatile material for different commercial applications such as transparent electrodes, piezoelectric devices, varistors, SAW devices etc because of its high piezoelectric coupling, greater stability of its hexagonal phase and its pyroelectric property. In fact, ZnO is a potential material for gas sensor ...

  17. Development of gas sensors using ZnO nanostructures

    Indian Academy of Sciences (India)

    Administrator

    Different ZnO nanostructures such as nanowires, nanobelts and tetrapods have been grown and used for preparation of thick film (with random ... Gas sensors; nanowires; ZnO; tetrapods; NO; H2S. 1. Introduction. Semiconductor metal-oxide .... at room temperature is shown in figure 3. Here, response is defined by: 100.

  18. Conductivity modeling of gas sensors based on copper ...

    African Journals Online (AJOL)

    The main objective of this work is to study the electronic conductivity of copper phthalocyanine (CuPc) thin films in presence of certain strong oxidizing gases involved in air pollution, particularly NO2, for use as gas sensor devices. To achieve this objective, the first part presents a study of the conductivity evolution of these ...

  19. Fast response time alcohol gas sensor using nanocrystalline F ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 36; Issue 4. Fast response time alcohol gas sensor using nanocrystalline F-doped SnO2 films derived via sol–gel method. Sarbani Basu Yeong-Her Wang C Ghanshyam Pawan Kapur. Volume 36 Issue 4 August 2013 pp 521-533 ...

  20. Improved zinc oxide film for gas sensor applications

    Indian Academy of Sciences (India)

    Unknown

    Improved zinc oxide film for gas sensor applications. S ROY and S BASU*. Materials Science Centre, Indian Institute of Technology, Kharagpur 721 302, India. Abstract. Zinc oxide (ZnO) is a versatile material for different commercial applications such as transparent electrodes, piezoelectric devices, varistors, SAW devices ...

  1. Development of gas sensors using ZnO nanostructures

    Indian Academy of Sciences (India)

    Administrator

    *For correspondence. Development of gas sensors using ZnO nanostructures. S K GUPTA. 1,. *, ADITEE JOSHI. 2 and MANMEET KAUR. 1. 1. Technical Physics and Prototype Engineering Division, Bhabha Atomic Research Centre,. Mumbai 400 085. 2. Department of Electronics Science, University of Pune, Pune 411 007.

  2. Fast response time alcohol gas sensor using nanocrystalline F

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 36; Issue 4. Fast response time alcohol gas sensor using nanocrystalline F-doped SnO2 films derived via sol–gel method. Sarbani Basu Yeong-Her Wang C Ghanshyam Pawan Kapur. Volume 36 Issue 4 August 2013 pp 521-533 ...

  3. Fast response time alcohol gas sensor using nanocrystalline F ...

    Indian Academy of Sciences (India)

    Fast response time alcohol gas sensor using nanocrystalline F-doped. SnO2 films derived via sol–gel method. SARBANI BASU, YEONG-HER WANG†, C GHANSHYAM. ∗ and PAWAN KAPUR. CSIR-Central Scientific Instruments Organisation, Sector-30, Chandigarh 160 030, India. †Department of Electrical Engineering, ...

  4. Thin-film antifuses for pellistor type gas sensors

    NARCIS (Netherlands)

    Kovalgin, Alexeij Y.; Holleman, J.; van den Berg, Albert; Wallinga, Hans

    2001-01-01

    This work extends our previously reported idea of using the nano-scale conductive link (antifuse) as a combined heating /detecting element in a Pellistor-type gas sensor. Our new thin-film antifuse is designed in such a way that the oxide, for minimising the bulk influence on surface temperature,

  5. Chemical discrimination in turbulent gas mixtures with MOX sensors validated by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Fonollosa, Jordi; Rodríguez-Luján, Irene; Trincavelli, Marco; Vergara, Alexander; Huerta, Ramón

    2014-10-16

    Chemical detection systems based on chemo-resistive sensors usually include a gas chamber to control the sample air flow and to minimize turbulence. However, such a kind of experimental setup does not reproduce the gas concentration fluctuations observed in natural environments and destroys the spatio-temporal information contained in gas plumes. Aiming at reproducing more realistic environments, we utilize a wind tunnel with two independent gas sources that get naturally mixed along a turbulent flow. For the first time, chemo-resistive gas sensors are exposed to dynamic gas mixtures generated with several concentration levels at the sources. Moreover, the ground truth of gas concentrations at the sensor location was estimated by means of gas chromatography-mass spectrometry. We used a support vector machine as a tool to show that chemo-resistive transduction can be utilized to reliably identify chemical components in dynamic turbulent mixtures, as long as sufficient gas concentration coverage is used. We show that in open sampling systems, training the classifiers only on high concentrations of gases produces less effective classification and that it is important to calibrate the classification method with data at low gas concentrations to achieve optimal performance.

  6. Hydrogen Gas Sensors Based on Semiconductor Oxide Nanostructures

    Directory of Open Access Journals (Sweden)

    Yongming Hu

    2012-04-01

    Full Text Available Recently, the hydrogen gas sensing properties of semiconductor oxide (SMO nanostructures have been widely investigated. In this article, we provide a comprehensive review of the research progress in the last five years concerning hydrogen gas sensors based on SMO thin film and one-dimensional (1D nanostructures. The hydrogen sensing mechanism of SMO nanostructures and some critical issues are discussed. Doping, noble metal-decoration, heterojunctions and size reduction have been investigated and proved to be effective methods for improving the sensing performance of SMO thin films and 1D nanostructures. The effect on the hydrogen response of SMO thin films and 1D nanostructures of grain boundary and crystal orientation, as well as the sensor architecture, including electrode size and nanojunctions have also been studied. Finally, we also discuss some challenges for the future applications of SMO nanostructured hydrogen sensors.

  7. Invariant Observer-Based State Estimation for Micro-Aerial Vehicles in GPS-Denied Indoor Environments Using an RGB-D Camera and MEMS Inertial Sensors

    Directory of Open Access Journals (Sweden)

    Dachuan Li

    2015-04-01

    Full Text Available This paper presents a non-linear state observer-based integrated navigation scheme for estimating the attitude, position and velocity of micro aerial vehicles (MAV operating in GPS-denied indoor environments, using the measurements from low-cost MEMS (micro electro-mechanical systems inertial sensors and an RGB-D camera. A robust RGB-D visual odometry (VO approach was developed to estimate the MAV’s relative motion by extracting and matching features captured by the RGB-D camera from the environment. The state observer of the RGB-D visual-aided inertial navigation was then designed based on the invariant observer theory for systems possessing symmetries. The motion estimates from the RGB-D VO were fused with inertial and magnetic measurements from the onboard MEMS sensors via the state observer, providing the MAV with accurate estimates of its full six degree-of-freedom states. Implementations on a quadrotor MAV and indoor flight test results demonstrate that the resulting state observer is effective in estimating the MAV’s states without relying on external navigation aids such as GPS. The properties of computational efficiency and simplicity in gain tuning make the proposed invariant observer-based navigation scheme appealing for actual MAV applications in indoor environments.

  8. A novel Gravity-FREAK feature extraction and Gravity-KLT tracking registration algorithm based on iPhone MEMS mobile sensor in mobile environment.

    Science.gov (United States)

    Hong, Zhiling; Lin, Fan; Xiao, Bin

    2017-01-01

    Based on the traditional Fast Retina Keypoint (FREAK) feature description algorithm, this paper proposed a Gravity-FREAK feature description algorithm based on Micro-electromechanical Systems (MEMS) sensor to overcome the limited computing performance and memory resources of mobile devices and further improve the reality interaction experience of clients through digital information added to the real world by augmented reality technology. The algorithm takes the gravity projection vector corresponding to the feature point as its feature orientation, which saved the time of calculating the neighborhood gray gradient of each feature point, reduced the cost of calculation and improved the accuracy of feature extraction. In the case of registration method of matching and tracking natural features, the adaptive and generic corner detection based on the Gravity-FREAK matching purification algorithm was used to eliminate abnormal matches, and Gravity Kaneda-Lucas Tracking (KLT) algorithm based on MEMS sensor can be used for the tracking registration of the targets and robustness improvement of tracking registration algorithm under mobile environment.

  9. Assessment of the Integration Strategy between GPS and Body-Worn MEMS Sensors with Application to Sports

    OpenAIRE

    Waegli, Adrian; Skaloud, Jan; Tomé, Phillip; Bonnaz, Jean-Marie

    2007-01-01

    This paper describes experiments that were performed involving a professional downhill skier equipped with a low-cost L1 GPS receiver and a MEMS-IMU composed of 3 single axis gyroscopes, accelerometers and magnetometers. In addition, the skier carried an L1/L2 GPS receiver and a tactical-grade IMU (LN200). The experiments aimed to assess the navigation performance of different GPS/MEMS-IMU integration strategies compared to high-quality GPS/INS integration. After presenting an overview...

  10. A smart microelectromechanical sensor and switch triggered by gas

    KAUST Repository

    Bouchaala, Adam M.

    2016-07-05

    There is an increasing interest to realize smarter sensors and actuators that can deliver a multitude of sophisticated functionalities while being compact in size and of low cost. We report here combining both sensing and actuation on the same device based on a single microstructure. Specifically, we demonstrate a smart resonant gas (mass) sensor, which in addition to being capable of quantifying the amount of absorbed gas, can be autonomously triggered as an electrical switch upon exceeding a preset threshold of absorbed gas. Toward this, an electrostatically actuated polymer microbeam is fabricated and is then functionalized with a metal-organic framework, namely, HKUST-1. The microbeam is demonstrated to absorb vapors up to a certain threshold, after which is shown to collapse through the dynamic pull-in instability. Upon pull-in, the microstructure can be made to act as an electrical switch to achieve desirable actions, such as alarming.

  11. Methods for gas detection using stationary hyperspectral imaging sensors

    Science.gov (United States)

    Conger, James L [San Ramon, CA; Henderson, John R [Castro Valley, CA

    2012-04-24

    According to one embodiment, a method comprises producing a first hyperspectral imaging (HSI) data cube of a location at a first time using data from a HSI sensor; producing a second HSI data cube of the same location at a second time using data from the HSI sensor; subtracting on a pixel-by-pixel basis the second HSI data cube from the first HSI data cube to produce a raw difference cube; calibrating the raw difference cube to produce a calibrated raw difference cube; selecting at least one desired spectral band based on a gas of interest; producing a detection image based on the at least one selected spectral band and the calibrated raw difference cube; examining the detection image to determine presence of the gas of interest; and outputting a result of the examination. Other methods, systems, and computer program products for detecting the presence of a gas are also described.

  12. Nanostructured Gas Sensors for Health Care: An Overview

    Science.gov (United States)

    Kaushik, Ajeet; Kumar, Rajesh; Jayant, Rahul Dev; Nair, Madhavan

    2015-01-01

    Nanostructured platforms have been utilized for fabrication of small, sensitive and reliable gas sensing devices owing to high functionality, enhanced charge transport and electro-catalytic property. As a result of globalization, rapid, sensitive and selective detection of gases in environment is essential for health care and security. Nonmaterial such as metal, metal oxides, organic polymers, and organic-inorganic hybrid nanocomposites exhibit interesting optical, electrical, magnetic and molecular properties, and hence are found potential gas sensing materials. Morphological, electrical, and optical properties of such nanostructures can be tailored via controlling the precursor concentration and synthesis conditions resulting to achieve desired sensing. This review presents applications of nano-enabling gas sensors to detect gases for environment monitoring. The recent update, challenges, and future vision for commercial applications of such sensor are also described here. PMID:26491544

  13. Gas detection with microelectromechanical Fabry-Perot interferometer technology in cell phone

    Science.gov (United States)

    Mannila, Rami; Hyypiö, Risto; Korkalainen, Marko; Blomberg, Martti; Kattelus, Hannu; Rissanen, Anna

    2015-06-01

    VTT Technical Research Centre of Finland has developed a miniaturized optical sensor for gas detection in a cell phone. The sensor is based on a microelectromechanical (MEMS) Fabry-Perot interferometer, which is a structure with two highly reflective surfaces separated by a tunable air gap. The MEMS FPI is a monolithic device, i.e. it is made entirely on one substrate in a batch process, without assembling separate pieces together. The gap is adjusted by moving the upper mirror with electrostatic force, so there are no actual moving parts. VTT has designed and manufactured a MEMS FPI based carbon dioxide sensor demonstrator which is integrated to a cell phone shield cover. The demonstrator contains light source, gas cell, MEMS FPI, detector, control electronics and two coin cell batteries as a power source. It is connected to the cell phone by Bluetooth. By adjusting the wavelength range and customizing the MEMS FPI structure, it is possible to selectively sense multiple gases.

  14. DNA sensor cGAS-mediated immune recognition

    Directory of Open Access Journals (Sweden)

    Pengyan Xia

    2016-09-01

    Full Text Available Abstract The host takes use of pattern recognition receptors (PRRs to defend against pathogen invasion or cellular damage. Among microorganism-associated molecular patterns detected by host PRRs, nucleic acids derived from bacteria or viruses are tightly supervised, providing a fundamental mechanism of host defense. Pathogenic DNAs are supposed to be detected by DNA sensors that induce the activation of NFκB or TBK1-IRF3 pathway. DNA sensor cGAS is widely expressed in innate immune cells and is a key sensor of invading DNAs in several cell types. cGAS binds to DNA, followed by a conformational change that allows the synthesis of cyclic guanosine monophosphate–adenosine monophosphate (cGAMP from adenosine triphosphate and guanosine triphosphate. cGAMP is a strong activator of STING that can activate IRF3 and subsequent type I interferon production. Here we describe recent progresses in DNA sensors especially cGAS in the innate immune responses against pathogenic DNAs.

  15. Flexible Graphene-Based Wearable Gas and Chemical Sensors.

    Science.gov (United States)

    Singh, Eric; Meyyappan, M; Nalwa, Hari Singh

    2017-10-11

    Wearable electronics is expected to be one of the most active research areas in the next decade; therefore, nanomaterials possessing high carrier mobility, optical transparency, mechanical robustness and flexibility, lightweight, and environmental stability will be in immense demand. Graphene is one of the nanomaterials that fulfill all these requirements, along with other inherently unique properties and convenience to fabricate into different morphological nanostructures, from atomically thin single layers to nanoribbons. Graphene-based materials have also been investigated in sensor technologies, from chemical sensing to detection of cancer biomarkers. The progress of graphene-based flexible gas and chemical sensors in terms of material preparation, sensor fabrication, and their performance are reviewed here. The article provides a brief introduction to graphene-based materials and their potential applications in flexible and stretchable wearable electronic devices. The role of graphene in fabricating flexible gas sensors for the detection of various hazardous gases, including nitrogen dioxide (NO 2 ), ammonia (NH 3 ), hydrogen (H 2 ), hydrogen sulfide (H 2 S), carbon dioxide (CO 2 ), sulfur dioxide (SO 2 ), and humidity in wearable technology, is discussed. In addition, applications of graphene-based materials are also summarized in detecting toxic heavy metal ions (Cd, Hg, Pb, Cr, Fe, Ni, Co, Cu, Ag), and volatile organic compounds (VOCs) including nitrobenzene, toluene, acetone, formaldehyde, amines, phenols, bisphenol A (BPA), explosives, chemical warfare agents, and environmental pollutants. The sensitivity, selectivity and strategies for excluding interferents are also discussed for graphene-based gas and chemical sensors. The challenges for developing future generation of flexible and stretchable sensors for wearable technology that would be usable for the Internet of Things (IoT) are also highlighted.

  16. 21 CFR 870.4410 - Cardiopulmonary bypass in-line blood gas sensor.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass in-line blood gas sensor... Cardiopulmonary bypass in-line blood gas sensor. (a) Identification. A cardiopulmonary bypass in-line blood gas sensor is a transducer that measures the level of gases in the blood. (b) Classification. Class II...

  17. Robust Design of SAW Gas Sensors by Taguchi Dynamic Method

    Directory of Open Access Journals (Sweden)

    Hsun-Heng Tsai

    2009-02-01

    Full Text Available This paper adopts Taguchi’s signal-to-noise ratio analysis to optimize the dynamic characteristics of a SAW gas sensor system whose output response is linearly related to the input signal. The goal of the present dynamic characteristics study is to increase the sensitivity of the measurement system while simultaneously reducing its variability. A time- and cost-efficient finite element analysis method is utilized to investigate the effects of the deposited mass upon the resonant frequency output of the SAW biosensor. The results show that the proposed methodology not only reduces the design cost but also promotes the performance of the sensors.

  18. Optical graphene quantum dots gas sensors: Theoretical study

    Science.gov (United States)

    Raeyani, D.; Shojaei, S.; Ahmadi-Kandjani, S.

    2018-02-01

    In this work, we theoretically studied the changes of graphene quantum dots (GQD) absorption spectra under the influence of different gases to indicate optical gas sensing features of GQDs. The adsorption of gas molecules such as CO2, N2 and Ar on GQDs have been theoretically investigated through time-dependent density functional theory (TDDFT) calculations. Our study revealed that UV-Vis absorption spectrum of GQDs in the presence of CO2 undergoes considerable changes than that of N2 and Ar. The shift of maximum absorption wavelength for adsorption of CO2, N2 and Ar in same distance from GQD in addition to density of state (DOS) and orbital analyses have been obtained. To verify our theoretical results, comparison with experimental study has been done and good agreement has been observed. Comparing with electrical property of GQD, optical properties showed an efficient tool to be implemented in gas adsorption and paves the way towards GQD optical gas sensors.

  19. Desain Alat Pendeteksi Kebocoran Gas LPG Menggunakan Sensor MQ-6 Berbasis ATmega8

    OpenAIRE

    Sirait, Hannayeni

    2017-01-01

    Sensor MQ 6 is a gas sensors are used to detect LPG, iso-butane, propane with high sensitivity. Gas sensor MQ-6 has a small sensitivity to a drug alcohol and cigarette smoke. Gas sensor MQ-6 is a sensor that has a rapid response to the LPG / Liquid Petroleum Gas, stable and durable, and can be used in a simple drive circuit. The sensor was developed by micro Al2O3 ceramic tube, Tin Dioxide (SnO2) sensitive layer, measuring electrode and heater are fixed into a layer of skin cre...

  20. A Novel Single-Axis MEMS Tilt Sensor with a High Sensitivity in the Measurement Range from 0∘to 360∘.

    Science.gov (United States)

    Wang, Shudong; Wei, Xueyong; Weng, Yinsheng; Zhao, Yulong; Jiang, Zhuangde

    2018-01-25

    In this paper, a novel single-axis MEMS tilt sensor is presented. It contains a hexagonal proof mass, six micro-lever force amplifiers and three double-ended-tuning fork (DETF) resonant strain gauges. The proof mass is placed in the center with the micro-levers and the DETFs radially arrayed around. The variation of gravity acceleration applied on the proof mass will result in frequency shifts of the DETFs. Angular tilt can be got by analyzing the frequency outputs. The structural design of the tilt sensor is optimized by finite element simulation and the device is microfabricated using a silicon-on-insulator process, followed by open-loop and closed-loop characterizations. Results show that the scale factor of such sensor is at least 11.53 Hz/degree. Minimum Allan deviation of the DETF oscillator is 220 ppb (parts per billion) of the resonant frequency for an 5 s integration time. Resolution of the tilt sensor is 0.002 ∘ in the whole measurement range from 0 ∘ to 360 ∘ .

  1. A Novel Single-Axis MEMS Tilt Sensor with a High Sensitivity in the Measurement Range from 0∘ to 360∘

    Directory of Open Access Journals (Sweden)

    Shudong Wang

    2018-01-01

    Full Text Available In this paper, a novel single-axis MEMS tilt sensor is presented. It contains a hexagonal proof mass, six micro-lever force amplifiers and three double-ended-tuning fork (DETF resonant strain gauges. The proof mass is placed in the center with the micro-levers and the DETFs radially arrayed around. The variation of gravity acceleration applied on the proof mass will result in frequency shifts of the DETFs. Angular tilt can be got by analyzing the frequency outputs. The structural design of the tilt sensor is optimized by finite element simulation and the device is microfabricated using a silicon-on-insulator process, followed by open-loop and closed-loop characterizations. Results show that the scale factor of such sensor is at least 11.53 Hz/degree. Minimum Allan deviation of the DETF oscillator is 220 ppb (parts per billion of the resonant frequency for an 5 s integration time. Resolution of the tilt sensor is 0.002 ∘ in the whole measurement range from 0 ∘ to 360 ∘ .

  2. Laser deposition of sulfonated phthalocyanines for gas sensors

    Czech Academy of Sciences Publication Activity Database

    Fitl, Přemysl; Vrňata, M.; Kopecký, D.; Vlček, J.; Škodová, J.; Bulíř, Jiří; Novotný, Michal; Pokorný, Petr

    2014-01-01

    Roč. 302, MAY (2014), s. 37-41 ISSN 0169-4332. [European-Materials-Research-Society Symposium on Laser Material Interactions for Micro- and Nano- Applications /5./. Strasbourg, 27.05.2013-31.05.2013] R&D Projects: GA ČR(CZ) GAP108/11/1298 Institutional support: RVO:68378271 Keywords : Matrix Assisted Pulsed Laser Evaporation * substituted phthalocyanines * gas sensors * impedance measurements Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.711, year: 2014

  3. Effects of electron beam irradiation on tin dioxide gas sensors

    Indian Academy of Sciences (India)

    WINTEC

    Effects of electron beam irradiation on tin dioxide gas sensors. 85 tron irradiation dose. Under low irradiation dose, <300 kGy, the sensitivity of SnO2 thin film shifts slightly, from 300–. 850 kGy, the sensitivity increases greatly, at 850 kGy and it reaches 24⋅8. Then the sensitivity reaches maximum and remains stable while ...

  4. Chemoresistive Gas Sensors for the Detection of Colorectal Cancer Biomarkers

    OpenAIRE

    Malagù, Cesare; Fabbri, Barbara; Gherardi, Sandro; Giberti, Alessio; Guidi, Vincenzo; Landini, Nicolò; Zonta, Giulia

    2014-01-01

    Numerous medical studies show that tumor growth is accompanied by protein changes that may lead to the peroxidation of the cell membrane with consequent emission of volatile organic compounds (VOCs) by breath or intestinal gases that should be seen as biomarkers for colorectal cancer (CRC). The analysis of VOCs represents a non-invasive and potentially inexpensive preliminary screening technique. An array of chemoresistive gas sensors based on screen-printed metal oxide semiconducting films h...

  5. Open Path Trace Gas Laser Sensors for UAV Deployment

    Science.gov (United States)

    Shadman, S.; Mchale, L.; Rose, C.; Yalin, A.

    2015-12-01

    Novel trace gas sensors based on open-path Cavity Ring-down Spectroscopy (CRDS) are being developed to enable remote and mobile deployments including on small unmanned aerial systems (UAS). Relative to established closed-path CRDS instruments, the use of open-path configurations allows removal of the bulky and power hungry vacuum and flow system, potentially enabling lightweight and low power instruments with high sensitivity. However, open path operation introduces new challenges including the need to maintain mirror cleanliness, mitigation of particle optical effects, and the need to measure spectral features that are relatively broad. The present submission details open-path CRDS instruments for ammonia and methane and their planned use in UAS studies. The ammonia sensor uses a quantum cascade laser at 10.3 mm in a configuration in which the laser frequency is continuously swept and a trigger circuit and acousto-optic modulator (AOM) extinguish the light when the laser is resonant with the cavity. Ring-down signals are measured with a two-stage thermoelectrically cooled MCT photodetector. The cavity mirrors have reflectivity of 0.9995 and a noise equivalent absorption of 1.5 ppb Hz-1/2 was demonstrated. A first version of the methane sensor operated at 1.7um with a telecom diode laser while the current version operates at 3.6 um with an interband cascade laser (stronger absorption). We have performed validation measurements against known standards for both sensors. Compact optical assemblies are being developed for UAS deployment. For example, the methane sensor head will have target mass of designed for sensor control and signal processing with target mass <1 kg and power draw <10 W. The sensor size and power parameters are suitable for UAS deployment on both fixed wing and rotor style UAS. We plan to deploy the methane sensor to measure leakage and emission of methane from natural gas infrastructure, and to deploy both sensors together to study emissions from

  6. Inhomogeneous Oxygen Vacancy Distribution in Semiconductor Gas Sensors: Formation, Migration and Determination on Gas Sensing Characteristics

    OpenAIRE

    Liu, Jianqiao; Gao, Yinglin; Wu, Xu; Jin, Guohua; Zhai, Zhaoxia; Liu, Huan

    2017-01-01

    The density of oxygen vacancies in semiconductor gas sensors was often assumed to be identical throughout the grain in the numerical discussion of the gas-sensing mechanism of the devices. In contrast, the actual devices had grains with inhomogeneous distribution of oxygen vacancy under non-ideal conditions. This conflict between reality and discussion drove us to study the formation and migration of the oxygen defects in semiconductor grains. A model of the gradient-distributed oxygen vacanc...

  7. Trace Detection of Pentaerythritol Tetranitrate Using Electrochemical Gas Sensors

    Directory of Open Access Journals (Sweden)

    Praveen K. Sekhar

    2014-01-01

    Full Text Available Selective and sensitive detection of trace amounts of pentaerythritol tetranitrate (PETN is demonstrated. The screening system is based on a sampling/concentrator front end and electrochemical potentiometric gas sensor as the detector. A single sensor is operated in the dominant hydrocarbon (HC and nitrogen oxides (NOx mode by varying the sensor operating condition. The potentiometric sensor with integrated heaters was used to capture the signature of PETN. Quantitative measurements based on hydrocarbon and nitrogen oxide sensor responses indicated that the detector sensitivity scaled proportionally with the mass of the explosives (10 μg down to 200 ng. The ratio of the HC integrated peak area to the NOx integrated peak area is identified as an indicator of selectivity. The HC/NOx ratio is unique for PETN and has a range from 1.7 to 2.7. This detection technique has the potential to become an orthogonal technique to the existing explosive screening technologies for reducing the number of false positives/false negatives in a cost-effective manner.

  8. Best Frequency for Temperature Modulation of Tin Oxide Gas Sensor for Chemical Vapor Identification

    OpenAIRE

    R Chutia; M Bhuyan

    2014-01-01

    In this paper, we describe a method of optimum temperature modulation of metal oxide semiconductor (MOS) based gas sensor, operated in dynamic temperature measurement for identification of gas. The volatile organic compound (VOC) sample space consists of fourteen laboratory chemicals sampled at various concentration. We have used eleven number of gas sensors, manufactured by Figaro sensors, Japan. The heater of the sensors were modulated with sawtooth heating waveform of different frequency. ...

  9. Pollution Monitoring System Using Gas Sensor based on Wireless Sensor Network

    Directory of Open Access Journals (Sweden)

    M. Udin Harun Al Rasyid

    2016-01-01

    Full Text Available Carbon monoxide (CO and carbon dioxide (CO2 gases are classified as colorless and odorless gas so we need special tools to monitor their concentration in the air. Concentration of air pollution of CO and CO2 that are high in the air will give serious effects for health status. CO is a poisonous gas that damages the circulation of oxygen in the blood when inhaled, while CO2 is one of the gases that causes global warming. In this paper, we developed an integrated pollution monitoring (IPOM system to monitor the concentration of air pollution. This research implemented three sensor nodes (end-device which each node contains CO and CO2 sensors on the gas sensors board to perform sensing from the environment. Furthermore, the data taken from the environment by the sensor will be sent to the meshlium gateway using IEEE 802.15.4 Zigbee communications and processed by the gateway in order to be sent to the computer server. The data is stored in meshlium gateway using MySQL database as a backup, and it will be synchronized to the MySQL database in the computer server. We provide services for public to access the information in database server through a desktop and website application.

  10. Cobalt Doped SnO2 Thick Film Gas Sensors: Conductance and Gas Response Characteristics for LPG and CNG Gas

    OpenAIRE

    V. Kumar; S. K. Srivastava; Kiran Jain

    2009-01-01

    Cobalt doped thick films tin oxide sensors were studied for their LPG and CNG gas sensitivity. SnO2 powder was synthesized by precipitation technique and doped with cobalt sulphate (0 to 10 wt %) by impregnation technique. The sensing characteristics were found to depend on the cobalt concentration and operating temperature. Best performance for LPG and CNG detection was obtained for 3 wt % addition of cobalt sulphate. Cobalt doped SnO2 sensors showed a decrease in the optimum temperature for...

  11. A novel MOEMS pressure sensor: Modelling and experimental ...

    Indian Academy of Sciences (India)

    the pressurized gas and does not require a sealed cavity. Hence, compared to MEMS pres- sure sensors that are based on sealed cavities and require bonding, the structure is inherently free of mechanical 'creep' due to pressure cycling. In addition, a major advantage of using the MFPD sensor for the measurement of ...

  12. Development of polypyrrole coated copper nanowires for gas sensor application

    Directory of Open Access Journals (Sweden)

    H. Shokry Hassan

    2015-09-01

    Full Text Available Both polypyrrole (PPy and polypyrrole coated copper thin films were synthesized successfully via two-step methods. PPy nanorods films were first grown chemically, and then PPy thin films were fabricated on glass substrates using dip-coating technique. The resulting films were examined via various characterization methods such as X-ray diffraction (XRD, scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FT-IR and Thermal Gravimetric Analysis (TGA. Gas sensor devices were fabricated and the gas sensitivity for (PPy coated copper was measured as a function of temperature for both O2 and CO2 gases. The maximum sensitivity for O2 gas was around 160% and the maximum sensitivity for CO2 was 300%.

  13. [A mobile sensor for remote detection of natural gas leakage].

    Science.gov (United States)

    Zhang, Shuai; Liu, Wen-qing; Zhang, Yu-jun; Kan, Rui-feng; Ruan, Jun; Wang, Li-ming; Yu, Dian-qiang; Dong, Jin-ting; Han, Xiao-lei; Cui, Yi-ben; Liu, Jian-guo

    2012-02-01

    The detection of natural gas pipeline leak becomes a significant issue for body security, environmental protection and security of state property. However, the leak detection is difficult, because of the pipeline's covering many areas, operating conditions and complicated environment. A mobile sensor for remote detection of natural gas leakage based on scanning wavelength differential absorption spectroscopy (SWDAS) is introduced. The improved soft threshold wavelet denoising was proposed by analyzing the characteristics of reflection spectrum. And the results showed that the signal to noise ratio (SNR) was increased three times. When light intensity is 530 nA, the minimum remote sensitivity will be 80 ppm x m. A widely used SWDAS can make quantitative remote sensing of natural gas leak and locate the leak source precisely in a faster, safer and more intelligent way.

  14. MEMS Sensor Technologies for Human Centred Applications in Healthcare, Physical Activities, Safety and Environmental Sensing: A Review on Research Activities in Italy

    Science.gov (United States)

    Ciuti, Gastone; Ricotti, Leonardo; Menciassi, Arianna; Dario, Paolo

    2015-01-01

    Over the past few decades the increased level of public awareness concerning healthcare, physical activities, safety and environmental sensing has created an emerging need for smart sensor technologies and monitoring devices able to sense, classify, and provide feedbacks to users’ health status and physical activities, as well as to evaluate environmental and safety conditions in a pervasive, accurate and reliable fashion. Monitoring and precisely quantifying users’ physical activity with inertial measurement unit-based devices, for instance, has also proven to be important in health management of patients affected by chronic diseases, e.g., Parkinson’s disease, many of which are becoming highly prevalent in Italy and in the Western world. This review paper will focus on MEMS sensor technologies developed in Italy in the last three years describing research achievements for healthcare and physical activity, safety and environmental sensing, in addition to smart systems integration. Innovative and smart integrated solutions for sensing devices, pursued and implemented in Italian research centres, will be highlighted, together with specific applications of such technologies. Finally, the paper will depict the future perspective of sensor technologies and corresponding exploitation opportunities, again with a specific focus on Italy. PMID:25808763

  15. Listening to MEMS : An acoustic vibrometer

    NARCIS (Netherlands)

    Yntema, Doekle Reinder; Haneveld, J.; Engelen, Johannes Bernardus Charles; Brookhuis, Robert Anton; Sanders, Remco G.P.; Wiegerink, Remco J.; Elwenspoek, Michael Curt

    2010-01-01

    new way to characterize vibrating MEMS devices is presented. Using an acoustic particle velocity sensor the coupled sound field is measured, which is a measure for the movement of the MEMS device. We present several possible applications of this measurement method. It can be used as a read-out

  16. Data set from chemical sensor array exposed to turbulent gas mixtures.

    Science.gov (United States)

    Fonollosa, Jordi; Rodríguez-Luján, Irene; Trincavelli, Marco; Huerta, Ramón

    2015-06-01

    A chemical detection platform composed of 8 chemo-resistive gas sensors was exposed to turbulent gas mixtures generated naturally in a wind tunnel. The acquired time series of the sensors are provided. The experimental setup was designed to test gas sensors in realistic environments. Traditionally, chemical detection systems based on chemo-resistive sensors include a gas chamber to control the sample air flow and minimize turbulence. Instead, we utilized a wind tunnel with two independent gas sources that generate two gas plumes. The plumes get naturally mixed along a turbulent flow and reproduce the gas concentration fluctuations observed in natural environments. Hence, the gas sensors can capture the spatio-temporal information contained in the gas plumes. The sensor array was exposed to binary mixtures of ethylene with either methane or carbon monoxide. Volatiles were released at four different rates to induce different concentration levels in the vicinity of the sensor array. Each configuration was repeated 6 times, for a total of 180 measurements. The data is related to "Chemical Discrimination in Turbulent Gas Mixtures with MOX Sensors Validated by Gas Chromatography-Mass Spectrometry", by Fonollosa et al. [1]. The dataset can be accessed publicly at the UCI repository upon citation of [1]: http://archive.ics.uci.edu/ml/datasets/Gas+senso+rarray+exposed+to+turbulent+gas+mixtures.

  17. Highly Sensitive NiO Nanoparticle based Chlorine Gas Sensor

    Science.gov (United States)

    Arif, Mohd.; Sanger, Amit; Singh, Arun

    2018-03-01

    We have synthesized a chemiresistive sensor for chlorine (Cl2) gas in the range of 2-200 ppm based on nickel oxide (NiO) nanoparticles obtained by wet chemical synthesis. The nanoparticles were characterized by x-ray diffraction (XRD) analysis, field-emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, and photoluminescence (PL) spectroscopy. XRD spectra of the sensing layer revealed the cubic phase of NiO nanoparticles. The NiO nanoparticle size was calculated to be ˜ 21 nm using a Williamson-Hall plot. The bandgap of the NiO nanoparticles was found to be 3.13 eV using Tauc plots of the absorbance curve. Fast response time (12 s) and optimum recovery time (˜ 27 s) were observed for 10 ppm Cl2 gas at moderate temperature of 200°C. These results demonstrate the potential application of NiO nanoparticles for fabrication of highly sensitive and selective sensors for Cl2 gas.

  18. CO2 gas sensors based on rare earth oxycarbonates

    International Nuclear Information System (INIS)

    Haensch, Alexander

    2016-01-01

    This title presents a new type of CO 2 gas sensor, that allows the measurement of CO 2 gas with very low effort. The measurement principle is based on two semiconducting materials. One the ''receptor'' and a ''transducer'' form a semiconductor junction. Electronic changes in the receptor change the electrical resistance in the transducer and therefor allow the easy electrical measurement. The reactivity and the reaction mechanism is thoroughly studied. In the first part the basics and resistance measurements are presented. A comparison between different mixtures is done. The main part studies the surface chemistry with operando DRIFT spectroscopy. The chemical reactivity of different target gases and background gases is studied thoroughly. The electronic properties of Oxycarbonates and the combination of oxycarbonate and tin oxide were studied using operando Kelvin probes measurements. The result is that CO 2 alters the electron affinity of the material. Once moisture is present, an additional band bending is visible. The band bending dominated in a humid atmosphere, the work function changes. The electronic connection of oxycarbonate and tin oxide, the work function change of Oxycarbonates can be transferred to the tin oxide. Using the collected data, a basic idea of the operation will be presented by a two-semiconductor materials gas sensor.

  19. Selective, pulsed CVD of platinum on microfilament gas sensors

    Energy Technology Data Exchange (ETDEWEB)

    Manginell, R.P.; Smith, J.H.; Ricco, A.J.; Moreno, D.J.; Hughes, R.C. [Sandia National Labs., Albuquerque, NM (United States); Huber, R.J. [Utah Univ., Salt Lake City, UT (United States); Senturia, S.D. [Massachusetts Inst. of Tech., Cambridge, MA (United States)

    1996-05-01

    A post-processing, selective micro-chemical vapor deposition (``micro-CVD``) technology for the deposition of catalytic films on surface-micromachined, nitride-passivated polysilicon filaments has been investigated. Atmospheric pressure deposition of Pt on microfilaments was accomplished by thermal decomposition of Pt acetylacetonate; deposition occurs selectively only on those filaments which are electrically heated. Catalyst morphology, characterized by SEM, can be controlled by altering deposition time, filament temperature, and through the use of pulsed heating of the filament during deposition. Morphology plays an important role in determining the sensitivity of these devices when used as combustible gas sensors.

  20. Movable MEMS Devices on Flexible Silicon

    KAUST Repository

    Ahmed, Sally

    2013-05-05

    Flexible electronics have gained great attention recently. Applications such as flexible displays, artificial skin and health monitoring devices are a few examples of this technology. Looking closely at the components of these devices, although MEMS actuators and sensors can play critical role to extend the application areas of flexible electronics, fabricating movable MEMS devices on flexible substrates is highly challenging. Therefore, this thesis reports a process for fabricating free standing and movable MEMS devices on flexible silicon substrates; MEMS flexure thermal actuators have been fabricated to illustrate the viability of the process. Flexure thermal actuators consist of two arms: a thin hot arm and a wide cold arm separated by a small air gap; the arms are anchored to the substrate from one end and connected to each other from the other end. The actuator design has been modified by adding etch holes in the anchors to suit the process of releasing a thin layer of silicon from the bulk silicon substrate. Selecting materials that are compatible with the release process was challenging. Moreover, difficulties were faced in the fabrication process development; for example, the structural layer of the devices was partially etched during silicon release although it was protected by aluminum oxide which is not attacked by the releasing gas . Furthermore, the thin arm of the thermal actuator was thinned during the fabrication process but optimizing the patterning and etching steps of the structural layer successfully solved this problem. Simulation was carried out to compare the performance of the original and the modified designs for the thermal actuators and to study stress and temperature distribution across a device. A fabricated thermal actuator with a 250 μm long hot arm and a 225 μm long cold arm separated by a 3 μm gap produced a deflection of 3 μm before silicon release, however, the fabrication process must be optimized to obtain fully functioning

  1. Fabrication of a P3HT-ZnO Nanowires Gas Sensor Detecting Ammonia Gas

    Directory of Open Access Journals (Sweden)

    Chin-Guo Kuo

    2017-12-01

    Full Text Available In this study, an organic-inorganic semiconductor gas sensor was fabricated to detect ammonia gas. An inorganic semiconductor was a zinc oxide (ZnO nanowire array produced by atomic layer deposition (ALD while an organic material was a p-type semiconductor, poly(3-hexylthiophene (P3HT. P3HT was suitable for the gas sensing application due to its high hole mobility, good stability, and good electrical conductivity. In this work, P3HT was coated on the zinc oxide nanowires by the spin coating to form an organic-inorganic heterogeneous interface of the gas sensor for detecting ammonia gas. The thicknesses of the P3HT were around 462 nm, 397 nm, and 277 nm when the speeds of the spin coating were 4000 rpm, 5000 rpm, and 6000 rpm, respectively. The electrical properties and sensing characteristics of the gas sensing device at room temperature were evaluated by Hall effect measurement and the sensitivity of detecting ammonia gas. The results of Hall effect measurement for the P3HT-ZnO nanowires semiconductor with 462 nm P3HT film showed that the carrier concentration and the mobility were 2.7 × 1019 cm−3 and 24.7 cm2∙V−1∙s−1 respectively. The gas sensing device prepared by the P3HT-ZnO nanowires semiconductor had better sensitivity than the device composed of the ZnO film and P3HT film. Additionally, this gas sensing device could reach a maximum sensitivity around 11.58 per ppm.

  2. Fabrication of a P3HT-ZnO Nanowires Gas Sensor Detecting Ammonia Gas.

    Science.gov (United States)

    Kuo, Chin-Guo; Chen, Jung-Hsuan; Chao, Yi-Chieh; Chen, Po-Lin

    2017-12-25

    In this study, an organic-inorganic semiconductor gas sensor was fabricated to detect ammonia gas. An inorganic semiconductor was a zinc oxide (ZnO) nanowire array produced by atomic layer deposition (ALD) while an organic material was a p-type semiconductor, poly(3-hexylthiophene) (P3HT). P3HT was suitable for the gas sensing application due to its high hole mobility, good stability, and good electrical conductivity. In this work, P3HT was coated on the zinc oxide nanowires by the spin coating to form an organic-inorganic heterogeneous interface of the gas sensor for detecting ammonia gas. The thicknesses of the P3HT were around 462 nm, 397 nm, and 277 nm when the speeds of the spin coating were 4000 rpm, 5000 rpm, and 6000 rpm, respectively. The electrical properties and sensing characteristics of the gas sensing device at room temperature were evaluated by Hall effect measurement and the sensitivity of detecting ammonia gas. The results of Hall effect measurement for the P3HT-ZnO nanowires semiconductor with 462 nm P3HT film showed that the carrier concentration and the mobility were 2.7 × 10 19 cm -3 and 24.7 cm²∙V -1 ∙s -1 respectively. The gas sensing device prepared by the P3HT-ZnO nanowires semiconductor had better sensitivity than the device composed of the ZnO film and P3HT film. Additionally, this gas sensing device could reach a maximum sensitivity around 11.58 per ppm.

  3. An Autonomous Waist-Mounted Pedestrian Dead Reckoning System by Coupling Low-Cost MEMS Inertial Sensors and GPS Receiver for 3D Urban Navigation

    Directory of Open Access Journals (Sweden)

    Jin-feng Li

    2014-03-01

    Full Text Available Global positioning system (GPS offers a perfect solution to the 3-dimension(3D navigation. However, the GPS-only solution can’t provide continuous and accurate position information in the unfavourable environments, such as urban canyons, indoor buildings, dense foliages due to signal blockage, interference, or jamming etc. A pedestrian dead reckoning (PDR system integrating the self-contained inertial sensors with GPS receiver is proposed to provide a seamless outdoor/indoor 3D pedestrian navigation. The MEM sensor module attached to the user’s waist is composed of a 3-axis accelerometer, a 3-axis gyroscope, a 3-axis digital compass and a barometric pressure sensor, which doesn’t rely on any infrastructure. The positioning algorithm implements a loosely coupled GPS/PDR integration. The sensor data are fused via a complementary filter to reduce the integral drift and magnetic disturbance for accurate heading. The four key components of the PDR algorithm: step detection, stride length estimation, heading and position determination are described in detail and implemented by the microcontroller. The step is detected using the accelerometer signals by the combination of three approaches: sliding window, peak detection and zero-crossing. The step length is estimated using a simple linear relationship with the step frequency. By coupling the step length, azimuth and height, 3D navigation is achieved. The performance of the proposed system is carefully verified through several field outdoor and indoor walking tests. The positioning errors are below 3% of the total traveled distance. The main error source comes from the orientation estimation. The results indicate that the proposed system is effective in accurate tracking.

  4. Fault detection, isolation, and diagnosis of status self-validating gas sensor arrays.

    Science.gov (United States)

    Chen, Yin-Sheng; Xu, Yong-Hui; Yang, Jing-Li; Shi, Zhen; Jiang, Shou-da; Wang, Qi

    2016-04-01

    The traditional gas sensor array has been viewed as a simple apparatus for information acquisition in chemosensory systems. Gas sensor arrays frequently undergo impairments in the form of sensor failures that cause significant deterioration of the performance of previously trained pattern recognition models. Reliability monitoring of gas sensor arrays is a challenging and critical issue in the chemosensory system. Because of its importance, we design and implement a status self-validating gas sensor array prototype to enhance the reliability of its measurements. A novel fault detection, isolation, and diagnosis (FDID) strategy is presented in this paper. The principal component analysis-based multivariate statistical process monitoring model can effectively perform fault detection by using the squared prediction error statistic and can locate the faulty sensor in the gas sensor array by using the variables contribution plot. The signal features of gas sensor arrays for different fault modes are extracted by using ensemble empirical mode decomposition (EEMD) coupled with sample entropy (SampEn). The EEMD is applied to adaptively decompose the original gas sensor signals into a finite number of intrinsic mode functions (IMFs) and a residual. The SampEn values of each IMF and the residual are calculated to reveal the multi-scale intrinsic characteristics of the faulty sensor signals. Sparse representation-based classification is introduced to identify the sensor fault type for the purpose of diagnosing deterioration in the gas sensor array. The performance of the proposed strategy is compared with other different diagnostic approaches, and it is fully evaluated in a real status self-validating gas sensor array experimental system. The experimental results demonstrate that the proposed strategy provides an excellent solution to the FDID of status self-validating gas sensor arrays.

  5. Design and calibration of a six-axis MEMS sensor array for use in scoliosis correction surgery

    Science.gov (United States)

    Benfield, David; Yue, Shichao; Lou, Edmond; Moussa, Walied A.

    2014-08-01

    A six-axis sensor array has been developed to quantify the 3D force and moment loads applied in scoliosis correction surgery. Initially this device was developed to be applied during scoliosis correction surgery and augmented onto existing surgical instrumentation, however, use as a general load sensor is also feasible. The development has included the design, microfabrication, deployment and calibration of a sensor array. The sensor array consists of four membrane devices, each containing piezoresistive sensing elements, generating a total of 16 differential voltage outputs. The calibration procedure has made use of a custom built load application frame, which allows quantified forces and moments to be applied and compared to the outputs from the sensor array. Linear or non-linear calibration equations are generated to convert the voltage outputs from the sensor array back into 3D force and moment information for display or analysis.

  6. MEMS and Nano-Technology Clean Room

    Data.gov (United States)

    Federal Laboratory Consortium — The MEMS and Nano-Technology Clean Room is a state-of-the-art, 800 square foot, Class 1000-capable facility used for development of micro and sub-micro scale sensors...

  7. Resistive Ammonia Gas Sensor Based on Non-Stoichiometric Copper Sulfide Thin Films

    Directory of Open Access Journals (Sweden)

    Abhay A. Sagade

    2008-08-01

    Full Text Available Resistive ammonia gas sensor is fabricated by using solution growth technique deposited copper sulfide (Cu1.8S thin films. Structural and opto-electronic properties of the films are studied by X-ray diffraction, atomic force microscopy, optical absorbance and electrical resistance. Ammonia gas sensor response measured from 20 to 500 ppm concentration at room temperature (300 K. The sensor response is increases with gas concentration.

  8. Electro-thermal modeling of a microbridge gas sensor

    Energy Technology Data Exchange (ETDEWEB)

    Manginell, R.P.; Smith, J.H.; Ricco, A.J.; Hughes, R.C.; Moreno, D.J. [Sandia National Labs., Albuquerque, NM (United States); Huber, R.J. [Utah Univ., Salt Lake City, UT (United States). Dept. of Electrical Engineering

    1997-08-01

    Fully CMOS-compatible, surface-micromachined polysilicon microbridges have been designed, fabricated, and tested for use in catalytic, calorimetric gas sensing. To improve sensor behavior, extensive electro-thermal modeling efforts were undertaken using SPICE. The validity of the SPICE model was verified comparing its simulated behavior with experiment. Temperature distribution of an electrically heated microbridges was measured using an infrared microscope. Comparisons among the measured distribution, the SPICE simulation, and distributions obtained by analytical methods show that heating at the ends of a microbridges has important implications for device response. Additional comparisons between measured and simulated current-voltage characteristics, as well as transient response, further support the accuracy of the model. A major benefit of electro- thermal modeling with SPICE is the ability to simultaneously simulate the behavior of a device and its control/sensing electronics. Results for the combination of a unique constant-resistance control circuit and microbridges gas sensor are given. Models of in situ techniques for monitoring catalyst deposition are shown to be in agreement with experiment. Finally, simulated chemical response of the detector is compared with the data, and methods of improving response through modifications in bridge geometry are predicted.

  9. Development of a Multi-User Polyimide-MEMS Fabrication Process and its Application to MicroHotplates

    KAUST Repository

    Lizardo, Ernesto B.

    2013-05-08

    Micro-electro-mechanical systems (MEMS) became possible thanks to the silicon based technology used to fabricate integrated circuits. Originally, MEMS fabrication was limited to silicon based techniques and materials, but the expansion of MEMS applications brought the need of a wider catalog of materials, including polymers, now being used to fabricate MEMS. Polyimide is a very attractive polymer for MEMS fabrication due to its high temperature stability compared to other polymers, low coefficient of thermal expansion, low film stress and low cost. The goal of this thesis is to expand the Polyimide usage as structural material for MEMS by the development of a multi-user fabrication process for the integration of this polymer along with multiple metal layers on a silicon substrate. The process also integrates amorphous silicon as sacrificial layer to create free-standing structures. Dry etching is used to release the devices and avoid stiction phenomena. The developed process is used to fabricate platforms for micro-hotplate gas sensors. The fabrication steps for the platforms are described in detail, explaining the process specifics and capabilities. An initial testing of the micro-hotplate is presented. As the process was also used as educational tool, some designs made by students and fabricated with the Polyimide-MEMS process are also presented.

  10. New Fabrication Methodologies for the Development of Low Power Gas Sensors Based on Semiconducting Nanowires

    OpenAIRE

    Samà Monsonís, Jordi

    2016-01-01

    La tesis titulada New Fabrication Methodologies for the Development of Low Power Gas Sensors Based on Semiconducting Nanowires, se enmarca dentro de los sensores de gas para la monitorización ambiental de la calidad del aire, con el objetivo de detectar la presencia de gases nocivos para la salud humana. El trabajo desarrollado se basa en el uso de sensores de gas resistivos, es decir, que la adsorción de un gas en la superficie del sensor da lugar a un cambio en la conductividad del sens...

  11. Analysis of nanowire transistor based nitrogen dioxide gas sensor – A simulation study

    Directory of Open Access Journals (Sweden)

    Gaurav Saxena

    2015-06-01

    Full Text Available Sensors sensitivity, selectivity and stability has always been a prime design concern for gas sensors designers. Modeling and simulation of gas sensors aids the designers in improving their performance. In this paper, different routes for the modeling and simulation of a semiconducting gas sensor is presented. Subsequently, by employing one of the route, the response of Zinc Oxide nanowire transistor towards nitrogen dioxide ambient is simulated. In addition to the sensing mechanism, simulation study of gas species desorption by applying a recovery voltage is also presented.

  12. Inhomogeneous Oxygen Vacancy Distribution in Semiconductor Gas Sensors: Formation, Migration and Determination on Gas Sensing Characteristics.

    Science.gov (United States)

    Liu, Jianqiao; Gao, Yinglin; Wu, Xu; Jin, Guohua; Zhai, Zhaoxia; Liu, Huan

    2017-08-10

    The density of oxygen vacancies in semiconductor gas sensors was often assumed to be identical throughout the grain in the numerical discussion of the gas-sensing mechanism of the devices. In contrast, the actual devices had grains with inhomogeneous distribution of oxygen vacancy under non-ideal conditions. This conflict between reality and discussion drove us to study the formation and migration of the oxygen defects in semiconductor grains. A model of the gradient-distributed oxygen vacancy was proposed based on the effects of cooling rate and re-annealing on semiconductive thin films. The model established the diffusion equations of oxygen vacancy according to the defect kinetics of diffusion and exclusion. We described that the steady-state and transient-state oxygen vacancy distributions, which were used to calculate the gas-sensing characteristics of the sensor resistance and response to reducing gases under two different conditions. The gradient-distributed oxygen vacancy model had the applications in simulating the sensor performances, such as the power law, the grain size effect and the effect of depletion layer width.

  13. Inhomogeneous Oxygen Vacancy Distribution in Semiconductor Gas Sensors: Formation, Migration and Determination on Gas Sensing Characteristics

    Directory of Open Access Journals (Sweden)

    Jianqiao Liu

    2017-08-01

    Full Text Available The density of oxygen vacancies in semiconductor gas sensors was often assumed to be identical throughout the grain in the numerical discussion of the gas-sensing mechanism of the devices. In contrast, the actual devices had grains with inhomogeneous distribution of oxygen vacancy under non-ideal conditions. This conflict between reality and discussion drove us to study the formation and migration of the oxygen defects in semiconductor grains. A model of the gradient-distributed oxygen vacancy was proposed based on the effects of cooling rate and re-annealing on semiconductive thin films. The model established the diffusion equations of oxygen vacancy according to the defect kinetics of diffusion and exclusion. We described that the steady-state and transient-state oxygen vacancy distributions, which were used to calculate the gas-sensing characteristics of the sensor resistance and response to reducing gases under two different conditions. The gradient-distributed oxygen vacancy model had the applications in simulating the sensor performances, such as the power law, the grain size effect and the effect of depletion layer width.

  14. MEMS Calculator

    Science.gov (United States)

    SRD 166 MEMS Calculator (Web, free access)   This MEMS Calculator determines the following thin film properties from data taken with an optical interferometer or comparable instrument: a) residual strain from fixed-fixed beams, b) strain gradient from cantilevers, c) step heights or thicknesses from step-height test structures, and d) in-plane lengths or deflections. Then, residual stress and stress gradient calculations can be made after an optical vibrometer or comparable instrument is used to obtain Young's modulus from resonating cantilevers or fixed-fixed beams. In addition, wafer bond strength is determined from micro-chevron test structures using a material test machine.

  15. Gas Identification Using Passive UHF RFID Sensor Platform

    Directory of Open Access Journals (Sweden)

    Muhammad Ali AKBAR

    2015-11-01

    Full Text Available The concept of passive Radio Frequency Identification (RFID sensor tag is introduced to remove the dependency of current RFID platforms on battery life. In this paper, a gas identification system is presented using passive RFID sensor tag along with the processing unit. The RFID system is compliant to Electronics Product Code Generation 2 (EPC-Gen2 protocol in 902-928 MHz ISM band. Whereas the processing unit is implemented and analyzed in software and hardware platforms. The software platform uses MATLAB, whereas a High Level Synthesis (HLS tool is used to implement the processing unit on a Zynq platform. Moreover, two sets of different gases are used along with Principal Component Analysis (PCA and Linear Discriminant Analysis (LDA based feature reduction approaches to analyze in detail the best feature reduction approach for efficient classification of gas data. It is found that for the first set of gases, 90 % gases are identified using first three principal components, which is 7 % more efficient than LDA. However in terms of hardware overhead, LDA requires 50 % less hardware resources than PCA. The classification results for the second set of gases reveal that 91 % of gas classification is obtained using LDA and first four PCA, while LDA requires 52 % less hardware resources than PCA. The RFID tag used for transmission is implemented in 0.13 µm CMOS process, with simulated average power consumption of 2.6 µW from 1.2 V supply. ThingMagic M6e embedded reader is used for RFID platform implementation. It shows an output power of 31.5 dBm which allows a read range up to 9 meters.

  16. SnO2/PPy Screen-Printed Multilayer CO2 Gas Sensor

    Directory of Open Access Journals (Sweden)

    S.A. WAGHULEY

    2007-05-01

    Full Text Available Tin dioxide (SnO2 plays a dominant role in solid state gas sensors and exhibit sensitivity towards oxidizing and reducing gases by a variation of its electrical properties. The electrical conducting polymer-polypyrrole (PPy has high anisotropy of electrical conduction and used as a gas sensor. SnO2/PPy multilayer, pure SnO2, pure PPy sensors were prepared by screen-printing method on Al2O3 layer followed by glass substrate. The sensors were used for different concentration (ppm of CO2 gas investigation at room temperature (303 K. The sensitivity of SnO2/PPy multilayer sensor was found to be higher, compared with pure SnO2 and pure PPy sensors. The multilayer sensor exhibited improved stability. The response and recovery time of multilayer sensor were found to be ~2 min and ~10 min respectively.

  17. Photocatalytical Decomposition of Contaminants on Thin Film Gas Sensors

    International Nuclear Information System (INIS)

    Radecka, M.; Lyson, B.; Lubecka, M.; Czapla, A.; Zakrzewska, K.

    2010-01-01

    Gas sensing materials have been prepared in a form of TiO 2 -SnO 2 thin films by rf reactive sputtering from Ti:SnO 2 and Sn:TiO 2 targets. Material studies have been performed by scanning electron microscopy, atomic force microscopy, X-ray diffraction at grazing incidence, Moessbauer spectroscopy, X-ray photoelectron spectroscopy and optical spectrophotometry. Dynamic gas sensing responses have been recorded as reproducible changes in the electrical resistance upon introduction of hydrogen at a partial pressure of 100-6000 ppm over a wide temperature range 473-873 K. Contamination experiments have been carried out with the motor oil (40 vol.% solution in CCl 4 ) in order to study the effect of UV light illumination on the gas sensor response. Optical spectroscopy has been applied to monitor the photodecomposition of the test compound, bromothymol blue. The Electronic Nose, ALPHA MOS FOX 4000 has been used in order to differentiate between different groups of motor oil vapors. (author)

  18. Cobalt Doped SnO2 Thick Film Gas Sensors: Conductance and Gas Response Characteristics for LPG and CNG Gas

    Directory of Open Access Journals (Sweden)

    V. Kumar

    2009-02-01

    Full Text Available Cobalt doped thick films tin oxide sensors were studied for their LPG and CNG gas sensitivity. SnO2 powder was synthesized by precipitation technique and doped with cobalt sulphate (0 to 10 wt % by impregnation technique. The sensing characteristics were found to depend on the cobalt concentration and operating temperature. Best performance for LPG and CNG detection was obtained for 3 wt % addition of cobalt sulphate. Cobalt doped SnO2 sensors showed a decrease in the optimum temperature for CNG detection from 450°C to 350°C. The transient response characteristics were determined at different temperatures and doping concentrations to understand the effect of doping on the rate kinetics. A correlation was established between response time, sensor response and the intergranular potential barriers.

  19. Chemoresistive Gas Sensors for the Detection of Colorectal Cancer Biomarkers

    Directory of Open Access Journals (Sweden)

    Cesare Malagù

    2014-10-01

    Full Text Available Numerous medical studies show that tumor growth is accompanied by protein changes that may lead to the peroxidation of the cell membrane with consequent emission of volatile organic compounds (VOCs by breath or intestinal gases that should be seen as biomarkers for colorectal cancer (CRC. The analysis of VOCs represents a non-invasive and potentially inexpensive preliminary screening technique. An array of chemoresistive gas sensors based on screen-printed metal oxide semiconducting films has been selected to discriminate gases of oncological interest, e.g., 1-iodononane and benzene, widely assumed to be biomarkers of colorectal cancer, from those of interference in the gut, such as methane and nitric oxide.

  20. Laboratory Connections: Gas Monitoring Transducers: Relative Humidity Sensors.

    Science.gov (United States)

    Powers, Michael H.; Hull, Stacey E.

    1988-01-01

    Explains the operation of five relative humidity sensors: psychrometer, hair hygrometer, resistance hygrometer, capacitance hygrometer, and resistance-capacitance hygrometer. Outlines the theory behind the electronic sensors and gives computer interfacing information. Lists sensor responses for calibration. (MVL)

  1. Indium oxide thin film based ammonia gas and ethanol vapour sensor

    Indian Academy of Sciences (India)

    Unknown

    The thin film gas sensor for ammonia was operated at different concentrations in the temperature range. 323–493 K. At 473 K the sensitivity of the sensor was found to be saturate. The detrimental effect of humidity on ammonia sensing is removed by intermittent periodic heating of the sensor at the two temperatures 323K.

  2. Multifunctional potentiometric gas sensor array with an integrated temperature control and temperature sensors

    Science.gov (United States)

    Blackburn, Bryan M; Wachsman, Eric D

    2015-05-12

    Embodiments of the subject invention relate to a gas sensor and method for sensing one or more gases. An embodiment incorporates an array of sensing electrodes maintained at similar or different temperatures, such that the sensitivity and species selectivity of the device can be fine tuned between different pairs of sensing electrodes. A specific embodiment pertains to a gas sensor array for monitoring combustion exhausts and/or chemical reaction byproducts. An embodiment of the subject device related to this invention operates at high temperatures and can withstand harsh chemical environments. Embodiments of the device are made on a single substrate. The devices can also be made on individual substrates and monitored individually as if they were part of an array on a single substrate. The device can incorporate sensing electrodes in the same environment, which allows the electrodes to be coplanar and, thus, keep manufacturing costs low. Embodiments of the device can provide improvements to sensitivity, selectivity, and signal interference via surface temperature control.

  3. Rebirth of Liquid Crystals for Sensoric Applications: Environmental and Gas Sensors

    Directory of Open Access Journals (Sweden)

    P. V. Shibaev

    2015-01-01

    Full Text Available Films and droplets of liquid crystals may soon become an essential part of sensitive environmental sensors and detectors of volatile organic compounds (VOCs in the air. In this paper a short overview of recent progress in the area of sensors based on liquid crystals is presented, along with the studies of low molar mass liquid crystals as gas sensors. The detection of VOCs in the air may rely on each of the following effects sequentially observed one after the other: (i slight changes in orientation and order parameter of liquid crystal, (ii formation of bubbles on the top of the liquid crystalline droplet, and (iii complete isotropisation of the liquid crystal. These three stages can be easily monitored by a photo camera and/or optical microscopy. Detection limits corresponding to the first stage are typically lower by a factor of at least 3–6 than detection limits corresponding to isotropisation. The qualitative model taking into account the reorientation of liquid crystals is presented to account for the observed changes.

  4. SENSOR GAS BERBASIS FILM TIPIS DENGAN KONFIGURASI TRANSISTOR EFEK MEDAN (FET UNTUK DETEKSI GAS CO

    Directory of Open Access Journals (Sweden)

    Sujarwata Sujarwata

    2013-02-01

    Full Text Available Pembuatan dan karakterisasi Transistor Efek Medan (FET berbasis film tipis dengan struktur bottom-contact dan panjang channel 100 ?m untuk aplikasi sensor gas. Pembuatan FET dengan cara: permulaan dilakukan pencucian substrat Si/SiO 2 dengan etanol dalam ultrasonic cleaner, kemudian dilakukan pendeposisian elektroda source/ drain dengan metode penguapan hampa udara dan teknik lithography. Selanjutnya dilakukan deposisi film tipis CuPc diantara source/drain sebagai panjang channel dan elektrode gate. Karakteristik FET, untuk daerah aktif untuk V DS (2,80 s/d 3,42 V dan kuat arus I (0,00095 s/d 0,00169 A. FET akan aktif beroperasi hanya diperlukan tegangan V DS (2,79 V s/d 3,43 V dan dengan ukuran sangat kecil ( 1,5 mm x 3,1 mm serta jarak antara S ke D adalah 100 ?m. Aplikasi sensor gas telah dilakukan untuk mendeteksi gas CO, diperoleh hasil untuk response time 90 detik dan recovery time 120 detik. DS

  5. Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, H. [PBI-Dansensor A/S (Denmark); Toft Soerensen, O. [Risoe National Lab., Materials Research Dept. (Denmark)

    1999-10-01

    A new type of ceramic oxygen sensors based on semiconducting oxides was developed in this project. The advantage of these sensors compared to standard ZrO{sub 2} sensors is that they do not require a reference gas and that they can be produced in small sizes. The sensor design and the techniques developed for production of these sensors are judged suitable by the participating industry for a niche production of a new generation of oxygen sensors. Materials research on new oxygen ion conducting conductors both for applications in oxygen sensors and in fuel was also performed in this project and finally a new process was developed for fabrication of ceramic tubes by dip-coating. (EHS)

  6. A Review on Innovative Procedures for the Analysis of Data from Gas Sensor Systems and Networks

    Directory of Open Access Journals (Sweden)

    Rolf Seifert

    2015-01-01

    Full Text Available Economic online and in-situ field analyses applications like discriminated alarming of smoldering fire or toxic gas leakages, monitoring of volatile components in chemical and biochemical processes, quality monitoring in food processing etc., wait for reliable and economic analytical solutions by sensor systems. This paper presents various innovative mathematical procedures to analyze data from gas sensor systems and gas sensor nets: ProSens - an efficient mathematical procedure for calibration and evaluation of tin oxide gas sensor data, SimSens – a mathematical program for simultaneous analysis of gases, ProCal - a program for batch-wise calibration of multi gas sensors and ProSource - a procedure for source localization. Applications to real data demonstrate the performance of the procedures.

  7. Study on the inside gas flow visualization of oxygen sensor cover; Kashika ni yoru O2 sensor cover nai no gas nagare hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Hocho, S.; Mitsuishi, Y.; Inagaki, M. [Nippon Soken, Inc., Tokyo (Japan); Hamaguchi, S.; Mizusawa, K. [Toyota Motor Corp., Aichi (Japan)

    1997-10-01

    In order to make clear the difference of the response time between the oxygen sensors with different protection covers, we visualized gas flow inside of sensor covers by means of two experimental methods: One is `Smoke Suspension Method` using liquid paraffin vapor as the smoke. With smoke suspension method, we detected the streamlines inside of the covers. The other is `Color Reaction Method` using the reaction of phenolphthalein and NH3 gas. With color reaction method, we confirmed the streamline inside of the cover and furthermore detected the difference of the response time of each sensor. 3 refs., 7 figs., 1 tab.

  8. Gas-sensing enhancement methods for hydrothermal synthesized SnO2 based sensors.

    Science.gov (United States)

    Zhao, Yalei; Zhang, Wenlong; Yang, Bin; Liu, Jingquan; Chen, Xiang; Wang, Xiaolin; Yang, Chunsheng

    2017-08-16

    The gas sensing enhancement methods for hydrothermal synthesized SnO2-based gas sensors could be performed from three areas: structural improvement, composition optimization and processing improvement, which were aimed to improve the performance of the gas sensors. There was 0-D, 1-D and 3-D structures reported in literatures. Controllable synthesis of different structures was deployed to increase specific surface area. Change of composition would intensively tailor the SnO2 structure, which affected the gas sensing performance. Besides, doping and compounding methods were adopted to promote gas-sensing performance by adjusting surface condition of SnO2 crystal and constructing heterojunction. As for processing area, it was very important to find the optimal reaction time and temperature. In this paper, gas-solid reaction rate constant was proposed to evaluate gas-sensing property and find the excellent hydrothermal synthesized SnO2-based gas sensor at present. © 2017 IOP Publishing Ltd.

  9. Challenges in the Packaging of MEMS

    Energy Technology Data Exchange (ETDEWEB)

    Malshe, A.P.; Singh, S.B.; Eaton, W.P.; O' Neal, C.; Brown, W.D.; Miller, W.M.

    1999-03-26

    The packaging of Micro-Electro-Mechanical Systems (MEMS) is a field of great importance to anyone using or manufacturing sensors, consumer products, or military applications. Currently much work has been done in the design and fabrication of MEMS devices but insufficient research and few publications have been completed on the packaging of these devices. This is despite the fact that packaging is a very large percentage of the total cost of MEMS devices. The main difference between IC packaging and MEMS packaging is that MEMS packaging is almost always application specific and greatly affected by its environment and packaging techniques such as die handling, die attach processes, and lid sealing. Many of these aspects are directly related to the materials used in the packaging processes. MEMS devices that are functional in wafer form can be rendered inoperable after packaging. MEMS dies must be handled only from the chip sides so features on the top surface are not damaged. This eliminates most current die pick-and-place fixtures. Die attach materials are key to MEMS packaging. Using hard die attach solders can create high stresses in the MEMS devices, which can affect their operation greatly. Low-stress epoxies can be high-outgassing, which can also affect device performance. Also, a low modulus die attach can allow the die to move during ultrasonic wirebonding resulting to low wirebond strength. Another source of residual stress is the lid sealing process. Most MEMS based sensors and devices require a hermetically sealed package. This can be done by parallel seam welding the package lid, but at the cost of further induced stress on the die. Another issue of MEMS packaging is the media compatibility of the packaged device. MEMS unlike ICS often interface with their environment, which could be high pressure or corrosive. The main conclusion we can draw about MEMS packaging is that the package affects the performance and reliability of the MEMS devices. There is a

  10. Theoretical and experimental research on the in-plane comb-shaped capacitor for MEMS coriolis mass flow sensor

    NARCIS (Netherlands)

    Hu, Chun; Zheng, Dezhi; Fan, Sangchun; Wiegerink, Remco J.; Guo, Zhanshe

    2015-01-01

    The Micro-Electro-Mechanical System Coriolis mass flow sensor uses a kind of in-plane comb-shaped capacitor to detect the vibration of tube containing the micro flow information. This paper takes the deflection of the micro tube caused by Coriolis force into account and models the in-plane

  11. Integration of Low-Power ASIC and MEMS Sensors for Monitoring Gastrointestinal Tract Using a Wireless Capsule System.

    Science.gov (United States)

    Arefin, Md Shamsul; Redoute, Jean-Michel; Yuce, Mehmet Rasit

    2018-01-01

    This paper presents a wireless capsule microsystem to detect and monitor the pH, pressure, and temperature of the gastrointestinal tract in real time. This research contributes to the integration of sensors (microfabricated capacitive pH, capacitive pressure, and resistive temperature sensors), frequency modulation and pulse width modulation based interface IC circuits, microcontroller, and transceiver with meandered conformal antenna for the development of a capsule system. The challenges associated with the system miniaturization, higher sensitivity and resolution of sensors, and lower power consumption of interface circuits are addressed. The layout, PCB design, and packaging of a miniaturized wireless capsule, having diameter of 13 mm and length of 28 mm, have successfully been implemented. A data receiver and recorder system is also designed to receive physiological data from the wireless capsule and to send it to a computer for real-time display and recording. Experiments are performed in vitro using a stomach model and minced pork as tissue simulating material. The real-time measurements also validate the suitability of sensors, interface circuits, and meandered antenna for wireless capsule applications.

  12. Semiconductor Gas Sensors Based on Pd/SnO2 Nanomaterials for Methane Detection in Air

    Science.gov (United States)

    Fedorenko, George; Oleksenko, Ludmila; Maksymovych, Nelly; Skolyar, Galina; Ripko, Oleksandr

    2017-05-01

    Semiconductor sensors based on nanosized Pd-containing tin dioxide have been obtained by a sol-gel technique. Semiconductor gas-sensitive materials were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD) methods. Influence of Pd additives on sensitivity of the sensors to methane has been studied. Temperature dependences of electrical resistance in air and sensor response to methane on palladium content for the sensors based on nanosized materials Pd/SnO2 have been investigated.

  13. A Robust and Low-Complexity Gas Recognition Technique for On-Chip Tin-Oxide Gas Sensor Array

    Directory of Open Access Journals (Sweden)

    Farid Flitti

    2008-01-01

    Full Text Available Gas recognition is a new emerging research area with many civil, military, and industrial applications. The success of any gas recognition system depends on its computational complexity and its robustness. In this work, we propose a new low-complexity recognition method which is tested and successfully validated for tin-oxide gas sensor array chip. The recognition system is based on a vector angle similarity measure between the query gas and the representatives of the different gas classes. The latter are obtained using a clustering algorithm based on the same measure within the training data set. Experimented results on our in-house gas sensors array show more than 98% of correct recognition. The robustness of the proposed method is tested by recognizing gas measurements with simulated drift. Less than 1% of performance degradation is noted at the worst case scenario which represents a significant improvement when compared to the current state-of-the-art.

  14. The Precise Mechanisms of a High-Speed Ultrasound Gas Sensor and Detecting Human-Specific Lung Gas Exchange

    Directory of Open Access Journals (Sweden)

    Hideki Toda

    2012-12-01

    Full Text Available In this paper, we propose and develop a new real-time human respiration process analysis method using a high-time-sampling gas concentration sensor based on ultrasound. A unique point about our proposed gas concentration sensor is its 1 kHz gas concentration sampling speed. This figure could not have been attained by previously proposed gas concentration measurement methods such as InfraRed, semiconductor gas sensors, or GC-MS, because the gas analysis speeds were a maximum of a few hundred milliseconds. First, we describe the proposed new ultrasound sound speed measurement method and the signal processing, and present the measurement circuit diagram. Next, we analyse the human respiration gas variation patterns of five healthy subjects using a newly developed gas-mask-type respiration sensor. This reveals that the rapid gas exchange from H2O to CO2 contains air specific to the human being. In addition, we also measured medical symptoms in subjects suffering from asthma, hyperventilation and bronchial asthma. The millisecond level high-speed analysis of the human respiration process will be useful for the next generation of healthcare, rehabilitation and sports science technology.

  15. Characterization and calibration of gas sensor systems at ppb level—a versatile test gas generation system

    Science.gov (United States)

    Leidinger, Martin; Schultealbert, Caroline; Neu, Julian; Schütze, Andreas; Sauerwald, Tilman

    2018-01-01

    This article presents a test gas generation system designed to generate ppb level gas concentrations from gas cylinders. The focus is on permanent gases and volatile organic compounds (VOCs) for applications like indoor and outdoor air quality monitoring or breath analysis. In the design and the setup of the system, several issues regarding handling of trace gas concentrations have been considered, addressed and tested. This concerns not only the active fluidic components (flow controllers, valves), which have been chosen specifically for the task, but also the design of the fluidic tubing regarding dead volumes and delay times, which have been simulated for the chosen setup. Different tubing materials have been tested for their adsorption/desorption characteristics regarding naphthalene, a highly relevant gas for indoor air quality monitoring, which has generated high gas exchange times in a previous gas mixing system due to long time adsorption/desorption effects. Residual gas contaminations of the system and the selected carrier air supply have been detected and quantified using both an analytical method (GC-MS analysis according to ISO 16000-6) and a metal oxide semiconductor gas sensor, which detected a maximum contamination equivalent to 28 ppb of carbon monoxide. A measurement strategy for suppressing even this contamination has been devised, which allows the system to be used for gas sensor and gas sensor system characterization and calibration in the low ppb concentration range.

  16. Micromachined thin-film sensors for SOI-CMOS co-integration

    CERN Document Server

    Laconte, Jean; Raskin, Jean-Pierre

    2006-01-01

    Co-integration of MEMS and MOS in SOI technology is promising and well demonstrated hereThe impact of Micromachining on SOI devices is deeply analyzed for the first timeInclude extensive TMAH etching, residual stress, microheaters, gas-flow sensors reviewResidual stresses in thin films need to be more and more monitored in MEMS designsTMAH micromachining is an attractive alternative to KOH.

  17. Estimation of the limit of detection in semiconductor gas sensors through linearized calibration models.

    Science.gov (United States)

    Burgués, Javier; Jiménez-Soto, Juan Manuel; Marco, Santiago

    2018-07-12

    The limit of detection (LOD) is a key figure of merit in chemical sensing. However, the estimation of this figure of merit is hindered by the non-linear calibration curve characteristic of semiconductor gas sensor technologies such as, metal oxide (MOX), gasFETs or thermoelectric sensors. Additionally, chemical sensors suffer from cross-sensitivities and temporal stability problems. The application of the International Union of Pure and Applied Chemistry (IUPAC) recommendations for univariate LOD estimation in non-linear semiconductor gas sensors is not straightforward due to the strong statistical requirements of the IUPAC methodology (linearity, homoscedasticity, normality). Here, we propose a methodological approach to LOD estimation through linearized calibration models. As an example, the methodology is applied to the detection of low concentrations of carbon monoxide using MOX gas sensors in a scenario where the main source of error is the presence of uncontrolled levels of humidity. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Development of CMOS MEMS inductive type tactile sensor with the integration of chrome steel ball force interface

    Science.gov (United States)

    Yeh, Sheng-Kai; Chang, Heng-Chung; Fang, Weileun

    2018-04-01

    This study presents an inductive tactile sensor with a chrome steel ball sensing interface based on the commercially available standard complementary metal–oxide–semiconductor (CMOS) process (the TSMC 0.18 µm 1P6M CMOS process). The tactile senor has a deformable polymer layer as the spring of the device and no fragile suspended thin film structures are required. As a tactile force is applied on the chrome steel ball, the polymer would deform. The distance between the chrome steel ball and the sensing coil would changed. Thus, the tactile force can be detected by the inductance change of the sensing coil. In short, the chrome steel ball acts as a tactile bump as well as the sensing interface. Experimental results show that the proposed inductive tactile sensor has a sensing range of 0–1.4 N with a sensitivity of 9.22(%/N) and nonlinearity of 2%. Preliminary wireless sensing test is also demonstrated. Moreover, the influence of the process and material issues on the sensor performances have also been investigated.

  19. Solid State Gas Sensor Research in Germany – a Status Report

    Directory of Open Access Journals (Sweden)

    Udo Weimar

    2009-06-01

    Full Text Available This status report overviews activities of the German gas sensor research community. It highlights recent progress in the field of potentiometric, amperometric, conductometric, impedimetric, and field effect-based gas sensors. It is shown that besides step-by-step improvements of conventional principles, e.g. by the application of novel materials, novel principles turned out to enable new markets. In the field of mixed potential gas sensors, novel materials allow for selective detection of combustion exhaust components. The same goal can be reached by using zeolites for impedimetric gas sensors. Operando spectroscopy is a powerful tool to learn about the mechanisms in n-type and in p-type conductometric sensors and to design knowledge-based improved sensor devices. Novel deposition methods are applied to gain direct access to the material morphology as well as to obtain dense thick metal oxide films without high temperature steps. Since conductometric and impedimetric sensors have the disadvantage that a current has to pass the gas sensitive film, film morphology, electrode materials, and geometrical issues affect the sensor signal. Therefore, one tries to measure directly the Fermi level position either by measuring the gas-dependent Seebeck coefficient at high temperatures or at room temperature by applying a modified miniaturized Kelvin probe method, where surface adsorption-based work function changes drive the drain-source current of a field effect transistor.

  20. Low Power Greenhouse Gas Sensors for Unmanned Aerial Vehicles

    Directory of Open Access Journals (Sweden)

    David J. Lary

    2012-05-01

    Full Text Available We demonstrate compact, low power, lightweight laser-based sensors for measuring trace gas species in the atmosphere designed specifically for electronic unmanned aerial vehicle (UAV platforms. The sensors utilize non-intrusive optical sensing techniques to measure atmospheric greenhouse gas concentrations with unprecedented vertical and horizontal resolution (~1 m within the planetary boundary layer. The sensors are developed to measure greenhouse gas species including carbon dioxide, water vapor and methane in the atmosphere. Key innovations are the coupling of very low power vertical cavity surface emitting lasers (VCSELs to low power drive electronics and sensitive multi-harmonic wavelength modulation spectroscopic techniques. The overall mass of each sensor is between 1–2 kg including batteries and each one consumes less than 2 W of electrical power. In the initial field testing, the sensors flew successfully onboard a T-Rex Align 700E robotic helicopter and showed a precision of 1% or less for all three trace gas species. The sensors are battery operated and capable of fully automated operation for long periods of time in diverse sensing environments. Laser-based trace gas sensors for UAVs allow for high spatial mapping of local greenhouse gas concentrations in the atmospheric boundary layer where land/atmosphere fluxes occur. The high-precision sensors, coupled to the ease-of-deployment and cost effectiveness of UAVs, provide unprecedented measurement capabilities that are not possible with existing satellite-based and suborbital aircraft platforms.

  1. Photonic crystal waveguides integrated with microcantilevers as a novel platform for gas sensors

    NARCIS (Netherlands)

    Pham Van So, P.V.S.; Kauppinen, L.J.; Dijkstra, Mindert; van Wolferen, Hendricus A.G.M.; de Ridder, R.M.; Hoekstra, Hugo

    We present results related to the simulation and fabrication of a novel and highly sensitive mechano-optical sensor for gas detection (i.e., hydrogen gas) based on microcantilevers, supplied with a selective gas absorption layer, suspended above a Si3N4 grated waveguide (GWG). The presence of a

  2. Catalysis-Based Cataluminescent and Conductometric Gas Sensors: Sensing Nanomaterials, Mechanism, Applications and Perspectives

    Directory of Open Access Journals (Sweden)

    Jinyun Liu

    2016-12-01

    Full Text Available Gas environment detection has become more urgent and significant, for both industrial manufacturing and environment monitoring. Gas sensors based on a catalytically-sensing mechanism are one of the most important types of devices for gas detection, and have been of great interest during the past decades. However, even though many efforts have contributed to this area, some great challenges still remain, such as the development of sensitively and selectively sensing catalysts. In this review, two representative catalysis-based gas sensors, cataluminescent and conductometric sensors, the basis of optical and electric signal acquisition, respectively, are summarized comprehensively. The current challenges have been presented. Recent research progress on the working mechanism, sensing nanomaterials, and applications reported by our group and some other researchers have been discussed systematically. The future trends and prospects of the catalysis-based gas sensors have also been presented.

  3. Advanced mechatronics and MEMS devices II

    CERN Document Server

    Wei, Bin

    2017-01-01

    This book introduces the state-of-the-art technologies in mechatronics, robotics, and MEMS devices in order to improve their methodologies. It provides a follow-up to "Advanced Mechatronics and MEMS Devices" (2013) with an exploration of the most up-to-date technologies and their applications, shown through examples that give readers insights and lessons learned from actual projects. Researchers on mechatronics, robotics, and MEMS as well as graduate students in mechanical engineering will find chapters on: Fundamental design and working principles on MEMS accelerometers Innovative mobile technologies Force/tactile sensors development Control schemes for reconfigurable robotic systems Inertial microfluidics Piezoelectric force sensors and dynamic calibration techniques ...And more. Authors explore applications in the areas of agriculture, biomedicine, advanced manufacturing, and space. Micro-assembly for current and future industries is also considered, as well as the design and development of micro and intel...

  4. Metal-oxide-semiconductor based gas sensors: screening, preparation, and integration.

    Science.gov (United States)

    Zhang, Jian; Qin, Ziyu; Zeng, Dawen; Xie, Changsheng

    2017-03-01

    Metal-oxide-semiconductor (MOS) based gas sensors have been considered a promising candidate for gas detection over the past few years. However, the sensing properties of MOS-based gas sensors also need to be further enhanced to satisfy the higher requirements for specific applications, such as medical diagnosis based on human breath, gas detection in harsh environments, etc. In these fields, excellent selectivity, low power consumption, a fast response/recovery rate, low humidity dependence and a low limit of detection concentration should be fulfilled simultaneously, which pose great challenges to the MOS-based gas sensors. Recently, in order to improve the sensing performances of MOS-based gas sensors, more and more researchers have carried out extensive research from theory to practice. For a similar purpose, on the basis of the whole fabrication process of gas sensors, this review gives a presentation of the important role of screening and the recent developments in high throughput screening. Subsequently, together with the sensing mechanism, the factors influencing the sensing properties of MOSs involved in material preparation processes were also discussed in detail. It was concluded that the sensing properties of MOSs not only depend on the morphological structure (particle size, morphology, pore size, etc.), but also rely on the defect structure and heterointerface structure (grain boundaries, heterointerfaces, defect concentrations, etc.). Therefore, the material-sensor integration was also introduced to maintain the structural stability in the sensor fabrication process, ensuring the sensing stability of MOS-based gas sensors. Finally, the perspectives of the MOS-based gas sensors in the aspects of fundamental research and the improvements in the sensing properties are pointed out.

  5. Data–driven modeling of nano-nose gas sensor arrays

    DEFF Research Database (Denmark)

    Alstrøm, Tommy Sonne; Larsen, Jan; Nielsen, Claus Højgård

    2010-01-01

    We present a data-driven approach to classification of Quartz Crystal Microbalance (QCM) sensor data. The sensor is a nano-nose gas sensor that detects concentrations of analytes down to ppm levels using plasma polymorized coatings. Each sensor experiment takes approximately one hour hence...... the number of available training data is limited. We suggest a data-driven classification model which work from few examples. The paper compares a number of data-driven classification and quantification schemes able to detect the gas and the concentration level. The data-driven approaches are based on state...

  6. Data-driven modeling of nano-nose gas sensor arrays

    DEFF Research Database (Denmark)

    Alstrøm, Tommy Sonne; Larsen, Jan; Nielsen, Claus Højgård

    2010-01-01

    We present a data-driven approach to classification of Quartz Crystal Microbalance (QCM) sensor data. The sensor is a nano-nose gas sensor that detects concentrations of analytes down to ppm levels using plasma polymorized coatings. Each sensor experiment takes approximately one hour hence...... the number of available training data is limited. We suggest a data-driven classification model which work from few examples. The paper compares a number of data-driven classification and quantification schemes able to detect the gas and the concentration level. The data-driven approaches are based on state...

  7. A Teaching - Learning Framework for MEMS Education

    International Nuclear Information System (INIS)

    Sheeparamatti, B G; Angadi, S A; Sheeparamatti, R B; Kadadevaramath, J S

    2006-01-01

    Micro-Electro-Mechanical Systems (MEMS) technology has been identified as one of the most promising technologies in the 21st century. MEMS technology has opened up a wide array of unforeseen applications. Hence it is necessary to train the technocrats of tomorrow in this emerging field to meet the industrial/societal demands. The drive behind fostering of MEMS technology is the reduction in the cost, size, weight, and power consumption of the sensors, actuators, and associated electronics. MEMS is a multidisciplinary engineering and basic science area which includes electrical engineering, mechanical engineering, material science and biomedical engineering. Hence MEMS education needs a special approach to prepare the technocrats for a career in MEMS. The modern education methodology using computer based training systems (CBTS) with embedded modeling and simulation tools will help in this direction. The availability of computer based learning resources such as MATLAB, ANSYS/Multiphysics and rapid prototyping tools have contributed to proposition of an efficient teaching-learning framework for MEMS education presented in this paper. This paper proposes a conceptual framework for teaching/learning MEMS in the current technical education scenario

  8. Membrane-Based Characterization of a Gas Component — A Transient Sensor Theory

    Directory of Open Access Journals (Sweden)

    Detlef Lazik

    2014-03-01

    Full Text Available Based on a multi-gas solution-diffusion problem for a dense symmetrical membrane this paper presents a transient theory of a planar, membrane-based sensor cell for measuring gas from both initial conditions: dynamic and thermodynamic equilibrium. Using this theory, the ranges for which previously developed, simpler approaches are valid will be discussed; these approaches are of vital interest for membrane-based gas sensor applications. Finally, a new theoretical approach is introduced to identify varying gas components by arranging sensor cell pairs resulting in a concentration independent gas-specific critical time. Literature data for the N2, O2, Ar, CH4, CO2, H2 and C4H10 diffusion coefficients and solubilities for a polydimethylsiloxane membrane were used to simulate gas specific sensor responses. The results demonstrate the influence of (i the operational mode; (ii sensor geometry and (iii gas matrices (air, Ar on that critical time. Based on the developed theory the case-specific suitable membrane materials can be determined and both operation and design options for these sensors can be optimized for individual applications. The results of mixing experiments for different gases (O2, CO2 in a gas matrix of air confirmed the theoretical predictions.

  9. SnO2 Nanostructure as Pollutant Gas Sensors: Synthesis, Sensing Performances, and Mechanism

    Directory of Open Access Journals (Sweden)

    Brian Yuliarto

    2015-01-01

    Full Text Available A significant amount of pollutants is produced from factories and motor vehicles in the form of gas. Their negative impact on the environment is well known; therefore detection with effective gas sensors is important as part of pollution prevention efforts. Gas sensors use a metal oxide semiconductor, specifically SnO2 nanostructures. This semiconductor is interesting and worthy of further investigation because of its many uses, for example, as lithium battery electrode, energy storage, catalyst, and transistor, and has potential as a gas sensor. In addition, there has to be a discussion of the use of SnO2 as a pollutant gas sensor especially for waste products such as CO, CO2, SO2, and NOx. In this paper, the development of the fabrication of SnO2 nanostructures synthesis will be described as it relates to the performances as pollutant gas sensors. In addition, the functionalization of SnO2 as a gas sensor is extensively discussed with respect to the theory of gas adsorption, the surface features of SnO2, the band gap theory, and electron transfer.

  10. Ce doped NiO nanoparticles as selective NO2 gas sensor

    Science.gov (United States)

    Gawali, Swati R.; Patil, Vithoba L.; Deonikar, Virendrakumar G.; Patil, Santosh S.; Patil, Deepak R.; Patil, Pramod S.; Pant, Jayashree

    2018-03-01

    Metal oxide gas sensors are promising portable gas detection devices because of their advantages such as low cost, easy production and compact size. The performance of such sensors is strongly dependent on material properties such as morphology, structure and doping. In the present study, we report the effect of cerium (Ce) doping on nickel oxide (NiO) nano-structured thin film sensors towards various gases. Bare NiO and Ce doped NiO nanoparticles (Ce:NiO) were synthesized by sol-gel method. To understand the effect of Ce doping in nickel oxide, various molar percentages of Ce with respect to nickel were incorporated. The structure, phase, morphology and band-gap energy of as-synthesized nanoparticles were studied by XRD, SEM, EDAX and UV-vis spectroscopy. Thin film gas sensors of all the samples were prepared and subjected to various gases such as LPG, NH3, CH3COCH3 and NO2. A systematic and comparative study reveals an enhanced gas sensing performance of Ce:NiO sensors towards NO2 gas. The maximum sensitivity for NO2 gas is around 0.719% per ppm at moderate operating temperature of 150 °C for 0.5% Ce:NiO thin film gas sensor. The enhanced gas sensing performance for Ce:NiO is attributed to the distortion of crystal lattice caused by doping of Ce into NiO.

  11. A novel design and analysis of a MEMS ceramic hot-wire anemometer for high temperature applications

    International Nuclear Information System (INIS)

    Nagaiah, N R; Sleiti, A K; Rodriguez, S; Kapat, J S; An, L; Chow, L

    2006-01-01

    This paper attempts to prove the feasibility of high temperature MEMS hot-wire anemometer for gas turbine environment. No such sensor exists at present. Based on the latest improvement in a new type of Polymer-Derived Ceramic (PDC) material, the authors present a Novel design, structural and thermal analysis of MEMS hot-wire anemometer (HWA) based on PDC material, and show that such a sensor is indeed feasible. This MEMS Sensor is microfabricated by using three types of PDC materials such as SiAlCN, SiCN (lightly doped) and SiCN (heavily doped) for sensing element (hot-wire), support prongs and connecting leads respectively. This novel hot wire anemometer can perform better than a conventional HWA in which the hot wire is made of tungsten or platinum-iridium. This type of PDC-HWA can be used in harsh environment due to its high temperature resistance, tensile strength and resistance to oxidation. This HWA is fabricated using microstereolithography as a novel microfabrication technique to manufacture the proposed MEMS Sensor

  12. Fabrication of 3D Carbon Microelectromechanical Systems (C-MEMS).

    Science.gov (United States)

    Pramanick, Bidhan; Martinez-Chapa, Sergio O; Madou, Marc; Hwang, Hyundoo

    2017-06-17

    A wide range of carbon sources are available in nature, with a variety of micro-/nanostructure configurations. Here, a novel technique to fabricate long and hollow glassy carbon microfibers derived from human hairs is introduced. The long and hollow carbon structures were made by the pyrolysis of human hair at 900 °C in a N2 atmosphere. The morphology and chemical composition of natural and pyrolyzed human hairs were investigated using scanning electron microscopy (SEM) and electron-dispersive X-ray spectroscopy (EDX), respectively, to estimate the physical and chemical changes due to pyrolysis. Raman spectroscopy was used to confirm the glassy nature of the carbon microstructures. Pyrolyzed hair carbon was introduced to modify screen-printed carbon electrodes ; the modified electrodes were then applied to the electrochemical sensing of dopamine and ascorbic acid. Sensing performance of the modified sensors was improved as compared to the unmodified sensors. To obtain the desired carbon structure design, carbon micro-/nanoelectromechanical system (C-MEMS/C-NEMS) technology was developed. The most common C-MEMS/C-NEMS fabrication process consists of two steps: (i) the patterning of a carbon-rich base material, such as a photosensitive polymer, using photolithography; and (ii) carbonization through the pyrolysis of the patterned polymer in an oxygen-free environment. The C-MEMS/NEMS process has been widely used to develop microelectronic devices for various applications, including in micro-batteries, supercapacitors, glucose sensors, gas sensors, fuel cells, and triboelectric nanogenerators. Here, recent developments of a high-aspect ratio solid and hollow carbon microstructures with SU8 photoresists are discussed. The structural shrinkage during pyrolysis was investigated using confocal microscopy and SEM. Raman spectroscopy was used to confirm the crystallinity of the structure, and the atomic percentage of the elements present in the material before and after

  13. Surface stress sensor based on MEMS Fabry-Perot interferometer with high wavelength selectivity for label-free biosensing

    Science.gov (United States)

    Takahashi, Toshiaki; Hizawa, Takeshi; Misawa, Nobuo; Taki, Miki; Sawada, Kazuaki; Takahashi, Kazuhiro

    2018-05-01

    We have developed a surface stress sensor based on a microelectromechanical Fabry-Perot interferometer with high wavelength selectivity by using Au half-mirrors, for highly sensitive label-free biosensing. When the target molecule is adsorbed by the antigen-antibody reaction onto a movable membrane with a thin Au film, which acts as an upper mirror of the optical interferometer, the amount of deflection of the movable membrane deflected by the change in surface stress can be detected with high sensitivity. To improve the signal at the small membrane deflection region of this biosensor resulting in detection of low concentration molecules, by integrating 50 nm-thick Au half-mirrors, the wavelength selectivity of the optical interferometer has been successfully improved 6.6 times. Furthermore, the peak shift in the reflection spectrum due to the adsorption of bovine serum albumin (BSA) antigen with a concentration of 10 ng ml-l by the antigen-antibody reaction was spectroscopically measured on the fabricated optical interferometer, and the deflection amount of the movable membrane after 10 min treatment was 2.4 times larger than that of nonspecific adsorption with the avidin molecules. This result indicated that the proposed sensor can be used for selective detection of low-concentration target antigen molecules.

  14. Advanced Gas Sensors Using SERS-Activated Waveguides

    Science.gov (United States)

    Lascola, Robert; McWhorter, Scott; Murph, Simona Hunyadi

    2010-08-01

    non-specific interactions between the surface coating and additional nanoparticles suspended in solution to which the analyte had been coupled. Clearly, for a gas sensor, such a scheme is not feasible, and in any event the reliance on the random configuration of the nanoparticles and the analyte is not expected to lead to efficient enhancement. Here, we report the creation of capillary coatings of self-assembled, aggregated high aspect ratio metallic nanoparticles (e.g. rod, wires) with a solution-phase technique. Self-assembly offers the possibility for a high density of SERS hot spots, which are often observed at the junction of adjacent particles. Shaped nanoparticles also enhance self-assembled deposition, and allow further control of the optical properties of the coating through manipulation of the morphology. SERS enhancements for gases are reported relative to mirrored capillaries and free-space measurements.

  15. On-chip growth of semiconductor metal oxide nanowires for gas sensors: A review

    Directory of Open Access Journals (Sweden)

    Chu Manh Hung

    2017-09-01

    Full Text Available Semiconductor metal oxide nanowires (SMO-NWs show great potential for novel gas sensor applications because of their distinct properties, such as a high surface area to volume aspect ratio, high crystallinity and perfect pathway for electron transfer (length of NW. SMO-NW sensors can be configured as resistors or field-effect transistors for gas detection and different configurations, such as a single NW, multiple NWs, and networked NW films, have been established. Surface-functionalizing NWs with catalyst elements and self-heating NWs provide additional advantages for highly selective and low-power consumption gas sensors. However, an appropriate design of SMO-NWs is of practical importance in enhancing the gas-sensing performance of SMO-NW sensors. The on-chip growth of SMO-NWs possesses many advantages which can thus be effectively used for the large-scale fabrication of SMO-NW sensors with improved gas response and stability. This review aims to provide up-to-date information on the on-chip fabrication of SnO2, ZnO, WO3, CuO, and other SMO-NW sensors. It also discusses a variety of promising approaches that help advance the on-chip fabrication of SMO-NW-based gas sensors and other NW-based devices.

  16. Chemical gas sensors and the characterization, monitoring and sensor technology needs of the US Department of Energy

    International Nuclear Information System (INIS)

    Bastiaans, G.J.; Haas, W.J. Jr.; Junk, G.A.

    1993-01-01

    The Office of Technology Development within the Dept. of Energy (DOE) has the responsibility of providing new technologies to aid the environmental restoration and waste management (ER/WM) activities of the DOE. There is a perception that application and judicious development of chemical sensor technologies could result in large cost savings and reduced risk to the health and safety of ER/WM personnel. A number of potential gas sensor applications which exist within DOE ER/WM operations are described. The capabilities of several chemical sensor technologies and their potential to meet the needs of ER/WM applications in the present or near term future are discussed

  17. Sensor Selection for Aircraft Engine Performance Estimation and Gas Path Fault Diagnostics

    Science.gov (United States)

    Simon, Donald L.; Rinehart, Aidan W.

    2016-01-01

    This paper presents analytical techniques for aiding system designers in making aircraft engine health management sensor selection decisions. The presented techniques, which are based on linear estimation and probability theory, are tailored for gas turbine engine performance estimation and gas path fault diagnostics applications. They enable quantification of the performance estimation and diagnostic accuracy offered by different candidate sensor suites. For performance estimation, sensor selection metrics are presented for two types of estimators including a Kalman filter and a maximum a posteriori estimator. For each type of performance estimator, sensor selection is based on minimizing the theoretical sum of squared estimation errors in health parameters representing performance deterioration in the major rotating modules of the engine. For gas path fault diagnostics, the sensor selection metric is set up to maximize correct classification rate for a diagnostic strategy that performs fault classification by identifying the fault type that most closely matches the observed measurement signature in a weighted least squares sense. Results from the application of the sensor selection metrics to a linear engine model are presented and discussed. Given a baseline sensor suite and a candidate list of optional sensors, an exhaustive search is performed to determine the optimal sensor suites for performance estimation and fault diagnostics. For any given sensor suite, Monte Carlo simulation results are found to exhibit good agreement with theoretical predictions of estimation and diagnostic accuracies.

  18. Enhancement of methane gas sensing characteristics of graphene oxide sensor by heat treatment and laser irradiation.

    Science.gov (United States)

    Assar, Mohammadreza; Karimzadeh, Rouhollah

    2016-12-01

    The present study uses a rapid, easy and practical method for cost-effective fabrication of a methane gas sensor. The sensor was made by drop-casting a graphene oxide suspension onto an interdigital circuit surface. The electrical conductivity and gas-sensing characteristics of the sensor were determined and then heat treatment and in situ laser irradiation were applied to improve the device conductivity and gas sensitivity. Real-time monitoring of the evolution of the device current as a function of heat treatment time revealed significant changes in the conductance of the graphene oxide sensor. The use of low power laser irradiation enhanced both the electrical conductivity and sensing response of the graphene oxide sensor. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Sensor Suits for Human Motion Detection

    National Research Council Canada - National Science Library

    Feng, Maria Q

    2006-01-01

    ... shape, the stiffness and the density. This sensor suit is made of soft and elastic fabrics embedded with arrays of MEMS sensors such as muscle stiffness sensor, ultrasonic sensors, accelerometers and optical fiber sensors, to measure...

  20. Harsh Environment Gas Sensor Array for Venus Atmospheric Measurements, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Makel Engineering and the Ohio State University propose to develop a harsh environment tolerant gas sensor array for atmospheric analysis in future Venus missions....

  1. High-Temperature, High-Bandwidth Fiber Optic Pressure and Temperature Sensors for Gas Turbine Applications

    National Research Council Canada - National Science Library

    Fielder, Robert S; Palmer, Matthew E

    2003-01-01

    ..., and redesign compressor and turbine stages based on actual measurements. There currently exists no sensor technology capable of making pressure measurements in the critical hot regions of gas turbine engines...

  2. Diode Laser-Based Sensor for Fast Measurement of Binary Gas Mixtures

    National Research Council Canada - National Science Library

    McNesby, Kevin

    1999-01-01

    The development and characterization of a gas sensor to measure binary mixtures of oxygen and the vapor from a series of volatile organic compounds, with a time resolution of 10 milliseconds, is described...

  3. Integrating Metal-Oxide-Decorated CNT Networks with a CMOS Readout in a Gas Sensor

    Directory of Open Access Journals (Sweden)

    Suhwan Kim

    2012-02-01

    Full Text Available We have implemented a tin-oxide-decorated carbon nanotube (CNT network gas sensor system on a single die. We have also demonstrated the deposition of metallic tin on the CNT network, its subsequent oxidation in air, and the improvement of the lifetime of the sensors. The fabricated array of CNT sensors contains 128 sensor cells for added redundancy and increased accuracy. The read-out integrated circuit (ROIC was combined with coarse and fine time-to-digital converters to extend its resolution in a power-efficient way. The ROIC is fabricated using a 0.35 µm CMOS process, and the whole sensor system consumes 30 mA at 5 V. The sensor system was successfully tested in the detection of ammonia gas at elevated temperatures.

  4. Toward high value sensing: monolayer-protected metal nanoparticles in multivariable gas and vapor sensors.

    Science.gov (United States)

    Potyrailo, Radislav A

    2017-08-29

    For detection of gases and vapors in complex backgrounds, "classic" analytical instruments are an unavoidable alternative to existing sensors. Recently a new generation of sensors, known as multivariable sensors, emerged with a fundamentally different perspective for sensing to eliminate limitations of existing sensors. In multivariable sensors, a sensing material is designed to have diverse responses to different gases and vapors and is coupled to a multivariable transducer that provides independent outputs to recognize these diverse responses. Data analytics tools provide rejection of interferences and multi-analyte quantitation. This review critically analyses advances of multivariable sensors based on ligand-functionalized metal nanoparticles also known as monolayer-protected nanoparticles (MPNs). These MPN sensing materials distinctively stand out from other sensing materials for multivariable sensors due to their diversity of gas- and vapor-response mechanisms as provided by organic and biological ligands, applicability of these sensing materials for broad classes of gas-phase compounds such as condensable vapors and non-condensable gases, and for several principles of signal transduction in multivariable sensors that result in non-resonant and resonant electrical sensors as well as material- and structure-based photonic sensors. Such features should allow MPN multivariable sensors to be an attractive high value addition to existing analytical instrumentation.

  5. Conductive polymer gas sensor for quantitative detection of methanol in Brazilian sugar-cane spirit

    OpenAIRE

    Péres, Laura Oliveira [UNIFESP; Li, Rosamaria W. C.; Yamauchi, Elaine Y.; Lippi, Renata; Gruber, Jonas

    2012-01-01

    A low-cost chemiresistive gas sensor is described, made by the deposition of a thin film of a conductive polymer, poly(2-dodecanoylsulfanyl-p-phenylenevinylene), doped with dodecylbenzenesulfonic acid (10%, w/w), onto interdigitated electrodes. the sensor exhibits linear electrical conductance changes in function of the concentration of methanol present in sugar-cane spirit in the range between 0.05% and 4.0%. Since the sensor is cheap, easy to fabricate, durable, presents low power consumpti...

  6. Improving the performance of gas sensors for electronic noses using zeolites as selectivity modifiers.

    OpenAIRE

    Paraskeva, T. C.

    2005-01-01

    The demanding problem of lack of selectivity in semiconducting oxide gas sensors was addressed by the combination of different technologies: shape and size selective catalysts (zeolites), chromium-titanium oxide sensing material and multi-electrode sensor arrays. Sensor devices were fabricated with additional shape and size selective catalysts (zeolites) of three different types (ZSM-5, (3 and Y) either printed over the top of the sensing material or admixed with it. The shape and size select...

  7. Indium oxide thin film based ammonia gas and ethanol vapour sensor

    Indian Academy of Sciences (India)

    Unknown

    Introduction. Gas sensors play vital role in detecting, monitoring and controlling the presence of hazardous and poisonous gases in the atmosphere at very low concentrations. Semicon- .... detailed procedure for deposition of indium tin oxide films and the effect of .... The conductance of the sensor was measured with digital.

  8. Exploitation of Unique Properties of Zeolites in the Development of Gas Sensors

    Directory of Open Access Journals (Sweden)

    Prabir K. Dutta

    2012-04-01

    Full Text Available The unique properties of microporous zeolites, including ion-exchange properties, adsorption, molecular sieving, catalysis, conductivity have been exploited in improving the performance of gas sensors. Zeolites have been employed as physical and chemical filters to improve the sensitivity and selectivity of gas sensors. In addition, direct interaction of gas molecules with the extraframework cations in the nanoconfined space of zeolites has been explored as a basis for developing new impedance-type gas/vapor sensors. In this review, we summarize how these properties of zeolites have been used to develop new sensing paradigms. There is a considerable breadth of transduction processes that have been used for zeolite incorporated sensors, including frequency measurements, optical and the entire gamut of electrochemical measurements. It is clear from the published literature that zeolites provide a route to enhance sensor performance, and it is expected that commercial manifestation of some of the approaches discussed here will take place. The future of zeolite-based sensors will continue to exploit its unique properties and use of other microporous frameworks, including metal organic frameworks. Zeolite composites with electronic materials, including metals will lead to new paradigms in sensing. Use of nano-sized zeolite crystals and zeolite membranes will enhance sensor properties and make possible new routes of miniaturized sensors.

  9. Status of the MEMS Industry: Evolution or MEMS Markets and of the Industrial Infrastructure

    Directory of Open Access Journals (Sweden)

    J. C. ELOY

    2007-12-01

    Full Text Available The MEMS markets in 2006 reached US$ 5.8 B and we can estimate that the 2011 MEMS markets will reach more than US $ 10.7 B, with very diverse growth rate depending on the devices and the applications: silicon microphone and RF MEMS are the fastest growing applications but the existing applications like ink jet head and pressure sensors are still growing at a rate of 4 % per year at least. The industrial infrastructure is changing, with more and more companies going to 8’’ manufacturing facilities and the strong growth of the MEMS foundry business. MEMS business is changing for more structured industry and high volume production.

  10. Study on Detection and Identification of Gas Sensor Based on Chromatographic Separation

    Directory of Open Access Journals (Sweden)

    Xiao Wanfu

    2014-08-01

    Full Text Available This paper developed a chromatographic separation and sensor based on a combination of gas detector, the common precursor gases such as acetone, ether, chloroform and other gas detection. According to the obtained experimental data, proposed one kind based on the principal component analysis and support vector machine algorithm of gas chromatography identification sensor signal processing and recognition; the method used for detection and identification of the air in the precursor gases combine tester self-developed, obtained very good result. This paper designed and developed a chromatographic separation and sensor based on the combination of gas detection instruments, to multi gas detection instrument. On separation characteristics using chromatography, to solve the traditional single common precursor gas detection. The use of a pre processing based on domestication, principal component analysis for feature extraction method of all kinds of gas data. This effectively avoids the sensor substrate voltage fluctuation and gas concentration effects on body recognition, and reduces the gas sample feature vector dimension.

  11. Shifting the Intertial Navigation Paradigm with the MEMS Technology

    Science.gov (United States)

    Crain, Timothy P., II; Bishop, Robert H.; Brady, Tye

    2010-01-01

    "Why don't you use MEMS?" is of the most common questions posed to navigation systems engineers designing inertial navigation solutions in the modern era. The question stems from a general understanding that great strides have been made in terrestrial MEMS accelerometers and attitude rate sensors in terms of accuracy, mass, and power. Yet, when compared on a unit-to-unit basis, MEMS devices do not provide comparable performance (accuracy) to navigation grade sensors in several key metrics. This paper will propose a paradigm shift where the comparison in performance is between multiple MEMS devices and a single navigation grade sensor. The concept is that systematically, a sufficient number of MEMS sensors may mathematically provide comparable performance to a single navigation grade device and be competitive in terms power and mass allocations when viewed on a systems level. The implication is that both inertial navigation system design and fault detection, identification, and recovery could benefit from a system of MEMS devices in the same way that swarm sensing has benefited Earth observation and astronomy. A survey of the state of the art in inertial sensor accuracy scaled by mass and power will be provided to show the scaled error in MEMS and navigation graded devices, a mathematical comparison of multi-unit to single-unit sensor errors will be developed, and preliminary application to an Orion lunar skip atmospheric entry trajectory will be explored.

  12. Shifting the Inertial Navigation Paradigm with MEMS Technology

    Science.gov (United States)

    Crain, Timothy; Brady, Tye; Bishop, Robert H.

    2010-01-01

    Why don t you use MEMS? is one of the most common questions posed to navigation systems engineers designing inertial navigation solutions in the modern era. The question stems from a general understanding that great strides have been made in terrestrial MEMS accelerometers and attitude rate sensors in terms of accuracy, mass, and power. Yet, when compared on a unit-to-unit basis, MEMS devices do not provide comparable performance (accuracy) to navigation grade sensors. This paper will propose a paradigm shift where the comparison in performance is between multiple MEMS devices and a single navigation grade sensor. The concept is that systematically, a sufficient number of MEMS sensors may mathematically provide comparable performance to a single navigation grade device and be competitive in terms power and mass allocations when viewed on a systems level. The implication is that both inertial navigation system design and fault detection, identification, and recovery could benefit from a system of MEMS devices in the same way that swarm sensing has benefited Earth observation and astronomy. A survey of the state of the art in inertial sensor accuracy scaled by mass and power will be provided to show the specific error in MEMS and navigation graded devices, a mathematical comparison of multi-unit to single-unit sensor errors will be developed, and preliminary applications to Constellation vehicles will be explored.

  13. Influence of Fabricating Process on Gas Sensing Properties of ZnO Nanofiber-Based Sensors

    Science.gov (United States)

    Xu, Lei; Wang, Rui; Liu, Yong; Dong, Liang

    2011-04-01

    ZnO nanofibers are synthesized by an electrospinning method and characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). Two types of gas sensors are fabricated by loading these nanofibers as the sensing materials and their performances are investigated in detail. Compared with the sensors based on traditional ceramic tubes with Au electrodes (traditional sensors), the sensors fabricated by spinning ZnO nanofibers on ceramic planes with Ag-Pd electrodes (plane sensors) exhibit much higher sensing properties. The sensitivity for the plane sensors is about 30 to 100 ppm ethanol at 300°C, while the value is only 13 for the traditional sensors. The response and recovery times are about 2 and 3s for the plane sensors and are 3 and 6s for the traditional sensors, respectively. Lower minimum-detection-limit is also found for the plane sensors. These improvements are explained by considering the morphological damage in the fabricating process for traditional sensors. The results suggest that the plane sensors are more suitable to sensing investigation for higher veracity.

  14. PDMS membranes as sensing element in optical sensors for gas detection in water

    Directory of Open Access Journals (Sweden)

    Stefania Torino

    2017-11-01

    Full Text Available Polydimethylsiloxane (PDMS has been introduced the first time about 20years ago. This polymer is worldwide used for the rapid prototyping of microfluidic device through a replica molding process. However, the great popularity of PDMS is not only related to its easy processability, but also to its chemical and physical properties. For its interesting properties, the polymer has been implied for several applications, including sensing. In this work, we investigated how to use functionalized PDMS membranes as sensing elements in optical sensors for gas detection in water samples. Keywords: Polydimethylsiloxane (PDMS, Surface Plasmon Resonance (SPR sensors, Gas sensor

  15. Breakdown voltage reduction by field emission in multi-walled carbon nanotubes based ionization gas sensor

    Energy Technology Data Exchange (ETDEWEB)

    Saheed, M. Shuaib M.; Muti Mohamed, Norani; Arif Burhanudin, Zainal, E-mail: zainabh@petronas.com.my [Centre of Innovative Nanostructures and Nanodevices, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia)

    2014-03-24

    Ionization gas sensors using vertically aligned multi-wall carbon nanotubes (MWCNT) are demonstrated. The sharp tips of the nanotubes generate large non-uniform electric fields at relatively low applied voltage. The enhancement of the electric field results in field emission of electrons that dominates the breakdown mechanism in gas sensor with gap spacing below 14 μm. More than 90% reduction in breakdown voltage is observed for sensors with MWCNT and 7 μm gap spacing. Transition of breakdown mechanism, dominated by avalanche electrons to field emission electrons, as decreasing gap spacing is also observed and discussed.

  16. Determination of chlorine concentration using single temperature modulated semiconductor gas sensor

    Science.gov (United States)

    Woźniak, Ł.; Kalinowski, P.; Jasiński, G.; Jasiński, P.

    2016-11-01

    A periodic temperature modulation using sinusoidal heater voltage was applied to a commercial SnO2 semiconductor gas sensor. Resulting resistance response of the sensor was analyzed using a feature extraction method based on Fast Fourier Transformation (FFT). The amplitudes of the higher harmonics of the FFT from the dynamic nonlinear responses of measured gas were further utilized as an input for Artificial Neuron Network (ANN). Determination of the concentration of chlorine was performed. Moreover, this work evaluates the sensor performance upon sinusoidal temperature modulation.

  17. METHOD FOR DETERMINATION OF THE CHARACTERISTIC CURVE OF THE THERMAL INERTIA OF AIRCRAFT GAS TEMPERATURE SENSORS

    Directory of Open Access Journals (Sweden)

    A. F. Sabitov

    2017-01-01

    Full Text Available The effectiveness of correction of the dynamic characteristics of gas temperature sensors in automatic control systems for the operation of aircraft gas turbine engines depends on the accuracy of the time constants of the sensors used from heat exchange conditions. The aim of this work was to develop a new method for determining the characteristic curves of the thermal inertia of gas temperature sensors.The new technique does not require finding the time constants of gas temperature sensors on the experimental transient characteristics. Characteristic curves for each time constant are defined as hyperbolic dependencies on the heat transfer coefficient of the gas temperature sensors sensing element with the gas flow. Parameters of hyperbolic dependencies are proposed to be established using two-dimensional regression analysis. For this purpose, special software has been developed in the Mathcad 14 and Mathcad 15. The software allows inputting the original data from the transient characteristics to the corresponding vectors or from tables in Excel format. It is shown that the transient characteristics in three-dimensional coordinates«time – heat transfer coefficient – the value of the transition characteristic» form a surface whose parameters are parameters of the desired hyperbolic dependencies.For a specific application of the technique, the regression functions for the dynamic characteristics of gas temperature sensors corresponding to the first and second orders are given. Analysis of the characteristic dependencies suggests that the proposed method more accurately establishes the dependence of the dynamic characteristics of aircraft gas temperature sensors on heat exchange conditions.It is shown that the algorithm of two-dimensional regression analysis realizes finding more accurate values of the parameters of the characteristic dependencies. The found parameters of the characteristic dependencies in a best way reach the surface of the

  18. Optical inspection of hidden MEMS structures

    Science.gov (United States)

    Krauter, Johann; Gronle, Marc; Osten, Wolfgang

    2017-06-01

    Micro-electro-mechanical system's (MEMS) applications have greatly expanded over the recent years, and the MEMS industry has grown almost exponentially. One of the strongest drivers are the automotive and consumer markets. A 100% test is necessary especially in the production of automotive MEMS sensors since they are subject to safety relevant functions. This inspection should be carried out before dicing and packaging since more than 90% of the production costs are incurred during these steps. An electrical test is currently being carried out with each MEMS component. In the case of a malfunction, the defect can not be located on the wafer because the MEMS are no longer optically accessible due to the encapsulation. This paper presents a low coherence interferometer for the topography measurement of MEMS structures located within the wafer stack. Here, a high axial and lateral resolution is necessary to identify defects such as stuck or bent MEMS fingers. First, the boundary conditions for an optical inspection system will be discussed. The setup is then shown with some exemplary measurements.

  19. THIN FILM-BASED SENSOR FOR MOTOR VEHICLE EXHAUST GAS, NH3, AND CO DETECTION

    Directory of Open Access Journals (Sweden)

    S. Sujarwata

    2016-10-01

    Full Text Available A copper phthalocyanine (CuPc thin film based gas sensor with FET structure and channel length 100 μm has been prepared by VE method and lithography technique to detect NH3, motor cycle exhaust gases and CO. CuPc material layer was deposited on SiO2 by the vacuum evaporator (VE method at room temperature and pressure of 8 x10-4 Pa. The stages of manufacturing gas sensor were Si/SiO2 substrate blenching with ethanol in an ultrasonic cleaner, source, and drain electrodes deposition on the substrate by using a vacuum evaporator, thin film deposition between the source/drain and gate deposition. The sensor response times to NH3, motorcycle exhaust gases and CO were 75 s, 135 s, and 150, respectively. The recovery times were 90 s, 150 s and 225, respectively. It is concluded that the CuPc thin film-based gas sensor with FET structure is the best sensor to detect the NH3 gas.Sensor gas berbasis film tipis copper phthalocyanine (CuPc berstruktur FET dengan panjang channel 100 μm telah dibuatdengan metode VE dan teknik lithography untuk mendeteksi NH3 gas buang kendaraan bermotor dan CO. Lapisan bahan CuPc dideposisikan pada permukaan silikon dioksida (SiO2 dengan metode vacuum evaporator (VE pada temperatur ruang dengan tekanan 8 x10-4 Pa. Tahapan pembuatan sensor gas adalah pencucian substrat Si/SiO2 dengan etanol dalam ultrasonic cleaner, deposisi elektroda source dan drain di atas substrat dengan metode vacuum evaporator, deposisi film tipis diantara source/drain dan deposisi gate. Waktu tanggap sensor terhadap NH3, gas buang kendaraan bermotor dan CO berturut-turut adalah 75 s, 135 s,dan 150 s. Waktu pemulihan berturut-turut adalah 90 s, 150 s,dan 225 s. Disimpulkan bahwa sensor gas berstruktur FET berbasis film tipis CuPc merupakan sensor paling baik untuk mendeteksi adanya gas NH3.

  20. Cr2O3 nanoparticle-functionalized WO3 nanorods for ethanol gas sensors

    Science.gov (United States)

    Choi, Seungbok; Bonyani, Maryam; Sun, Gun-Joo; Lee, Jae Kyung; Hyun, Soong Keun; Lee, Chongmu

    2018-02-01

    Pristine WO3 nanorods and Cr2O3-functionalized WO3 nanorods were synthesized by the thermal evaporation of WO3 powder in an oxidizing atmosphere, followed by spin-coating of the nanowires with Cr2O3 nanoparticles and thermal annealing in an oxidizing atmosphere. Scanning electron microscopy was used to examine the morphological features and X-ray diffraction was used to study the crystallinity and phase formation of the synthesized nanorods. Gas sensing tests were performed at different temperatures in the presence of test gases (ethanol, acetone, CO, benzene and toluene). The Cr2O3-functionalized WO3 nanorods sensor showed a stronger response to these gases relative to the pristine WO3 nanorod sensor. In particular, the response of the Cr2O3-functionalized WO3 nanorods sensor to 200 ppm ethanol gas was 5.58, which is approximately 4.4 times higher that of the pristine WO3 nanorods sensor. Furthermore, the Cr2O3-functionalized WO3 nanorods sensor had a shorter response and recovery time. The pristine WO3 nanorods had no selectivity toward ethanol gas, whereas the Cr2O3-functionalized WO3 nanorods sensor showed good selectivity toward ethanol. The gas sensing mechanism of the Cr2O3-functionalized WO3 nanorods sensor toward ethanol is discussed in detail.

  1. Approach for Self-Calibrating CO2 Measurements with Linear Membrane-Based Gas Sensors

    Directory of Open Access Journals (Sweden)

    Detlef Lazik

    2016-11-01

    Full Text Available Linear membrane-based gas sensors that can be advantageously applied for the measurement of a single gas component in large heterogeneous systems, e.g., for representative determination of CO2 in the subsurface, can be designed depending on the properties of the observation object. A resulting disadvantage is that the permeation-based sensor response depends on operating conditions, the individual site-adapted sensor geometry, the membrane material, and the target gas component. Therefore, calibration is needed, especially of the slope, which could change over several orders of magnitude. A calibration-free approach based on an internal gas standard is developed to overcome the multi-criterial slope dependency. This results in a normalization of sensor response and enables the sensor to assess the significance of measurement. The approach was proofed on the example of CO2 analysis in dry air with tubular PDMS membranes for various CO2 concentrations of an internal standard. Negligible temperature dependency was found within an 18 K range. The transformation behavior of the measurement signal and the influence of concentration variations of the internal standard on the measurement signal were shown. Offsets that were adjusted based on the stated theory for the given measurement conditions and material data from the literature were in agreement with the experimentally determined offsets. A measurement comparison with an NDIR reference sensor shows an unexpectedly low bias (<1% of the non-calibrated sensor response, and comparable statistical uncertainty.

  2. Approach for Self-Calibrating CO₂ Measurements with Linear Membrane-Based Gas Sensors.

    Science.gov (United States)

    Lazik, Detlef; Sood, Pramit

    2016-11-17

    Linear membrane-based gas sensors that can be advantageously applied for the measurement of a single gas component in large heterogeneous systems, e.g., for representative determination of CO₂ in the subsurface, can be designed depending on the properties of the observation object. A resulting disadvantage is that the permeation-based sensor response depends on operating conditions, the individual site-adapted sensor geometry, the membrane material, and the target gas component. Therefore, calibration is needed, especially of the slope, which could change over several orders of magnitude. A calibration-free approach based on an internal gas standard is developed to overcome the multi-criterial slope dependency. This results in a normalization of sensor response and enables the sensor to assess the significance of measurement. The approach was proofed on the example of CO₂ analysis in dry air with tubular PDMS membranes for various CO₂ concentrations of an internal standard. Negligible temperature dependency was found within an 18 K range. The transformation behavior of the measurement signal and the influence of concentration variations of the internal standard on the measurement signal were shown. Offsets that were adjusted based on the stated theory for the given measurement conditions and material data from the literature were in agreement with the experimentally determined offsets. A measurement comparison with an NDIR reference sensor shows an unexpectedly low bias (sensor response, and comparable statistical uncertainty.

  3. Development and Creating of Gas-Sensor System Based on Low Dimensional Metal Oxides

    Directory of Open Access Journals (Sweden)

    Bovhyra, R.V.

    2016-11-01

    Full Text Available Peculiarities of photoluminescent properties of metal oxide nanopowders (ZnO, TiO2, SnO2, WO3 including laser-modified and surface doped by impurities (Au, Ag, Pt, Ni, Cu, Sn, in gases (О2, N2, H2, CO, CO2 were studied. Nature of sensor properties of the metal oxide nanopowders (adsorption capacity, speed, sensitivity, selectivity were established; the best structure and materials for the development of a multicomponent recording matrix were selected. The efficiency of the constructed sensor system for the gases’ and their mixtures detection and analysis was found. The developed gas sensor system allows detecting not only separate gas components, but their mixture with high sensitivity and selectivity, providing the possibility to reach the modern level of the formation of gas sensor systems with improved performance.

  4. Identification and quantification of mixed air pollutants based on homotopy method for gas sensor array.

    Science.gov (United States)

    Yang, Yuning; Mason, Andrew J

    2012-01-01

    Accurate recognition of air pollutants and estimation of their concentrations are critical for human health and safety monitoring and can be achieved using gas sensor arrays. In this paper, an efficient method based on a homotopy algorithm is presented for the analysis of sensor arrays responding to binary mixtures. The new method models the responses of a gas sensor array as a system of nonlinear equations and provides a globally convergent way to find the solution of the system. Real data measurement for CH4 and SO2 are used to model sensor responses. The model is applied to the method for prediction and it shows the prediction results are within 1% variation of true values for both gas models.

  5. Development of Fabric-Based Chemical Gas Sensors for Use as Wearable Electronic Noses

    Directory of Open Access Journals (Sweden)

    Thara Seesaard

    2015-01-01

    Full Text Available Novel gas sensors embroidered into fabric substrates based on polymers/ SWNT-COOH nanocomposites were proposed in this paper, aiming for their use as a wearable electronic nose (e-nose. The fabric-based chemical gas sensors were fabricated by two main processes: drop coating and embroidery. Four potential polymers (PVC, cumene-PSMA, PSE and PVP/functionalized-SWCNT sensing materials were deposited onto interdigitated electrodes previously prepared by embroidering conductive thread on a fabric substrate to make an optimal set of sensors. After preliminary trials of the obtained sensors, it was found that the sensors yielded a electrical resistance in the region of a few kilo-Ohms. The sensors were tested with various volatile compounds such as ammonium hydroxide, ethanol, pyridine, triethylamine, methanol and acetone, which are commonly found in the wastes released from the human body. These sensors were used to detect and discriminate between the body odors of different regions and exist in various forms such as the urine, armpit and exhaled breath odor. Based on a simple pattern recognition technique, we have shown that the proposed fabric-based chemical gas sensors can discriminate the human body odor from two persons.

  6. Investigation of thiol derivatized gold nanoparticle sensors for gas analysis

    Science.gov (United States)

    Stephens, Jared S.

    Analysis of volatile organic compounds (VOCs) in air and exhaled breath by sensor array is a very useful testing technique. It can provide non-invasive, fast, inexpensive testing for many diseases. Breath analysis has been very successful in identifying cancer and other diseases by using a chemiresistor sensor or array with gold nanoparticles to detect biomarkers. Acetone is a biomarker for diabetes and having a portable testing device could help to monitor diabetic and therapeutic progress. An advantage to this testing method is it is conducted at room temperature instead of 200 degrees Celsius. 3. The objective of this research is to determine the effect of thiol derivatized gold nanoparticles based on sensor(s) detection of VOCs. The VOCs to be tested are acetone, ethanol, and a mixture of acetone and ethanol. Each chip is tested under all three VOCs and three concentration levels (0.1, 1, and 5.0 ppm). VOC samples are used to test the sensors' ability to detect and differentiate VOCs. Sensors (also referred to as a chip) are prepared using several types of thiol derivatized gold nanoparticles. The factors are: thiol compound and molar volume loading of the thiol in synthesis. The average resistance results are used to determine the VOC selectivity of the sensors tested. The results show a trend of increasing resistance as VOC concentration is increased relative to dry air; which is used as baseline for VOCs. Several sensors show a high selectivity to one or more VOCs. Overall the 57 micromoles of 4-methoxy-toluenethiol sensor shows the strongest selectivity for VOCs tested. 3. Gerfen, Kurt. 2012. Detection of Acetone in Air Using Silver Ion Exchanged ZSM-5 and Zinc Oxide Sensing Films. Master of Science thesis, University of Louisville.

  7. Semiconductor device-based sensors for gas, chemical, and biomedical applications

    CERN Document Server

    Ren, Fan

    2011-01-01

    Sales of U.S. chemical sensors represent the largest segment of the multi-billion-dollar global sensor market, which includes instruments for chemical detection in gases and liquids, biosensors, and medical sensors. Although silicon-based devices have dominated the field, they are limited by their general inability to operate in harsh environments faced with factors such as high temperature and pressure. Exploring how and why these instruments have become a major player, Semiconductor Device-Based Sensors for Gas, Chemical, and Biomedical Applications presents the latest research, including or

  8. Establishment and Application of Coalmine Gas Prediction Model Based on Multi-Sensor Data Fusion Technology

    Directory of Open Access Journals (Sweden)

    Wenyu Lv

    2014-04-01

    Full Text Available Undoubtedly an accident involving gas is one of the greater disasters that can occur in a coalmine, thus being able to predict when an accident involving gas might occur is an essential aspect in loss prevention and the reduction of safety hazards. However, the traditional methods concerning gas safety prediction is hindered by multi-objective and non-continuous problem. The coalmine gas prediction model based on multi-sensor data fusion technology (CGPM-MSDFT was established through analysis of accidents involving gas using artificial neural network to fuse multi- sensor data, using an improved algorithm designed to train the network and using an early stop method to resolve the over-fitting problem, the network test and field application results show that this model can provide a new direction for research into predicting the likelihood of a gas related incident within a coalmine. It will have a broad application prospect in coal mining.

  9. Microfabricated Gas Sensors Demonstrated in Fire and Emission Applications

    Science.gov (United States)

    Hunter, Gary W.

    2003-01-01

    A range of microfabricated chemical sensors are being developed to meet the needs of fire detection and emission monitoring in aerospace applications. These sensors have the advantages over traditional technology of minimal size, weight, and power consumption as well as the ability to be placed closer to where the measurements need to be made. Sensor arrays are being developed to address detection needs in environments where multiple species need to be measured. For example, the monitoring of chemical species such as carbon monoxide (CO), carbon dioxide (CO2), hydrocarbons, and other species is important in the detection of fires on airplanes and spacecraft. In contrast, different sensors are necessary for characterizing some aircraft engine designs where the monitoring of nitrogen oxides (NO(x)) and CO is of high interest. Demonstration of both fire and emission microsensor technology was achieved this year in a collaborative effort undertaken by the NASA Glenn Research Center, Case Western Reserve University, and Makel Engineering, Inc.

  10. Molecular-Resonance Fiber Optic Gas Sensors, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Aspen systems proposes to develop an innovative and smart sensors to continuously monitor ambient air compositions by utilizing a resonating tunable micro-cavity...

  11. Silicon Carbide-Based Hydrogen Gas Sensors for High-Temperature Applications

    Directory of Open Access Journals (Sweden)

    Sangchoel Kim

    2013-10-01

    Full Text Available We investigated SiC-based hydrogen gas sensors with metal-insulator-semiconductor (MIS structure for high temperature process monitoring and leak detection applications in fields such as the automotive, chemical and petroleum industries. In this work, a thin tantalum oxide (Ta2O5 layer was exploited with the purpose of sensitivity improvement, because tantalum oxide has good stability at high temperature with high permeability for hydrogen gas. Silicon carbide (SiC was used as a substrate for high-temperature applications. We fabricated Pd/Ta2O5/SiC-based hydrogen gas sensors, and the dependence of their I-V characteristics and capacitance response properties on hydrogen concentrations were analyzed in the temperature range from room temperature to 500 °C. According to the results, our sensor shows promising performance for hydrogen gas detection at high temperatures.

  12. Silicon carbide-based hydrogen gas sensors for high-temperature applications.

    Science.gov (United States)

    Kim, Seongjeen; Choi, Jehoon; Jung, Minsoo; Joo, Sungjae; Kim, Sangchoel

    2013-10-09

    We investigated SiC-based hydrogen gas sensors with metal-insulator-semiconductor (MIS) structure for high temperature process monitoring and leak detection applications in fields such as the automotive, chemical and petroleum industries. In this work, a thin tantalum oxide (Ta2O5) layer was exploited with the purpose of sensitivity improvement, because tantalum oxide has good stability at high temperature with high permeability for hydrogen gas. Silicon carbide (SiC) was used as a substrate for high-temperature applications. We fabricated Pd/Ta2O5/SiC-based hydrogen gas sensors, and the dependence of their I-V characteristics and capacitance response properties on hydrogen concentrations were analyzed in the temperature range from room temperature to 500 °C. According to the results, our sensor shows promising performance for hydrogen gas detection at high temperatures.

  13. Peptide Modified ZnO Nanoparticles as Gas Sensors Array for Volatile Organic Compounds (VOCs

    Directory of Open Access Journals (Sweden)

    Marcello Mascini

    2018-04-01

    Full Text Available In this work a peptide based gas sensor array based of ZnO nanoparticles (ZnONPs has been realized. Four different pentapeptides molecularly modeled for alcohols and esters having cysteine as a common spacer have been immobilized onto ZnONPs. ZnONPs have been morphologically and spectroscopically characterized. Modified nanoparticles have been then deposited onto quartz crystal microbalances (QCMs and used as gas sensors with nitrogen as carrier gas. Analysis of the pure compounds modeled demonstrated a nice fitting of modeling with real data. The peptide based ZnONPs had very low sensitivity to water, compared to previously studied AuNPs peptide based gas sensors allowing the use of the array on samples with high water content. Real samples of fruit juices have been assayed; stability of the signal, good repeatability, and discrimination ability of the array was achieved.

  14. Multiplexed Sensor for Synthesis Gas Compsition and Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Steven Buckley; Reza Gharavi; Marco Leon

    2007-10-01

    The overall goal of this project has been to develop a highly sensitive, multiplexed TDL-based sensor for CO{sub 2}, CO, H{sub 2}O (and temperature), CH{sub 4}, H{sub 2}S, and NH{sub 3}. Such a sensor was designed with so-called 'plug-and-play' characteristics to accommodate additional sensors, and provided in situ path-integrated measurements indicative of average concentrations at speeds suitable for direct gasifier control. The project developed the sensor and culminated in a real-world test of the underlying technology behind the sensor. During the project, new underlying measurements of spectroscopic constants for all of the gases of interest performed, in custom cells built for the project. The envisioned instrument was built from scratch from component lasers, fiber optics, amplifier blocks, detectors, etc. The sensor was tested for nearly a week in an operational power plant. The products of this research are expected to have a direct impact on gasifier technology and the production of high-quality syngas, with substantial broader application to coal and other energy systems. This report is the final technical report on project DE-FG26-04NT42172. During the project we completed all of the milestones planned in the project, with a modification of milestone (7) required due to lack of funding and personnel.

  15. Lightweight Fiber Optic Gas Sensor for Monitoring Regenerative Food Production

    Science.gov (United States)

    Schmidlin, Edward; Goswami, Kisholoy

    1995-01-01

    In this final report, Physical Optics Corporation (POC) describes its development of sensors for oxygen, carbon dioxide, and relative humidity. POC has constructed a phase fluorometer that can detect oxygen over the full concentration range from 0 percent to 100 percent. Phase-based measurements offer distinct advantages, such as immunity to source fluctuation, photobleaching, and leaching. All optics, optoelectronics, power supply, and the printed circuit board are included in a single box; the only external connections to the fluorometer are the optical fiber sensor and a power cord. The indicator-based carbon dioxide sensor is also suitable for short-term and discrete measurements over the concentration range from 0 percent to 100 percent. The optical fiber-based humidity sensor contains a porous core for direct interaction of the light beam with water vapor within fiber pores; the detection range for the humidity sensor is 10 percent to 100 percent, and response time is under five minutes. POC is currently pursuing the commercialization of these oxygen and carbon dioxide sensors for environmental applications.

  16. Analysis of Simulated Output Characteristics of Gas Sensor Based on Graphene Nanoribbon

    Directory of Open Access Journals (Sweden)

    A. Mahmoudi

    2016-01-01

    Full Text Available This work presents simulated output characteristics of gas sensor transistors based on graphene nanoribbon (GNRFET. The device studied in this work is a new generation of gas sensing devices, which are easy to use, ultracompact, ultrasensitive, and highly selective. We will explain how the exposure to the gas changes the conductivity of graphene nanoribbon. The equations of the GNRFET gas sensor model include the Poisson equation in the weak nonlocality approximation with proposed sensing parameters. As we have developed this model as a platform for a gas detection sensor, we will analyze the current-voltage characteristics after exposure of the GNRFET nanosensor device to NH3 gas. A sensitivity of nearly 2.7% was indicated in our sensor device after exposure of 1 ppm of NH3. The given results make GNRFET the right candidate for use in gas sensing/measuring appliances. Thus, we will investigate the effect of the channel length on the ON- and OFF-current.

  17. A pathway to eliminate the gas flow dependency of a hydrocarbon sensor for automotive exhaust applications

    Directory of Open Access Journals (Sweden)

    G. Hagen

    2018-02-01

    Full Text Available Gas sensors will play an essential role in future combustion-based mobility to effectively reduce emissions and monitor the exhausts reliably. In particular, an application in automotive exhausts is challenging due to the high gas temperatures that come along with highly dynamic flow rates. Recently, a thermoelectric hydrocarbon sensor was developed by using materials which are well known in the exhausts and therefore provide the required stability. As a sensing mechanism, the temperature difference that is generated between a catalytically activated area during the exothermic oxidation of said hydrocarbons and an inert area of the sensor is measured by a special screen-printed thermopile structure. As a matter of principle, this thermovoltage significantly depends on the mass flow rate of the exhausts under certain conditions. The present contribution helps to understand this cross effect and proposes a possible setup for its avoidance. By installing the sensor in the correct position of a bypass solution, the gas flow around the sensor is almost free of turbulence. Now, the signal depends only on the hydrocarbon concentration and not on the gas flow. Such a setup may open up new possibilities of applying novel sensors in automotive exhausts for on-board-measurement (OBM purposes.

  18. Diode laser absorption sensors for gas-dynamic and combustion flows

    Science.gov (United States)

    Allen, M. G.

    1998-01-01

    Recent advances in room-temperature, near-IR and visible diode laser sources for tele-communication, high-speed computer networks, and optical data storage applications are enabling a new generation of gas-dynamic and combustion-flow sensors based on laser absorption spectroscopy. In addition to conventional species concentration and density measurements, spectroscopic techniques for temperature, velocity, pressure and mass flux have been demonstrated in laboratory, industrial and technical flows. Combined with fibreoptic distribution networks and ultrasensitive detection strategies, compact and portable sensors are now appearing for a variety of applications. In many cases, the superior spectroscopic quality of the new laser sources compared with earlier cryogenic, mid-IR devices is allowing increased sensitivity of trace species measurements, high-precision spectroscopy of major gas constituents, and stable, autonomous measurement systems. The purpose of this article is to review recent progress in this field and suggest likely directions for future research and development. The various laser-source technologies are briefly reviewed as they relate to sensor applications. Basic theory for laser absorption measurements of gas-dynamic properties is reviewed and special detection strategies for the weak near-IR and visible absorption spectra are described. Typical sensor configurations are described and compared for various application scenarios, ranging from laboratory research to automated field and airborne packages. Recent applications of gas-dynamic sensors for air flows and fluxes of trace atmospheric species are presented. Applications of gas-dynamic and combustion sensors to research and development of high-speed flows aeropropulsion engines, and combustion emissions monitoring are presented in detail, along with emerging flow control systems based on these new sensors. Finally, technology in nonlinear frequency conversion, UV laser materials, room

  19. Fault diagnosis for micro-gas turbine engine sensors via wavelet entropy.

    Science.gov (United States)

    Yu, Bing; Liu, Dongdong; Zhang, Tianhong

    2011-01-01

    Sensor fault diagnosis is necessary to ensure the normal operation of a gas turbine system. However, the existing methods require too many resources and this need can't be satisfied in some occasions. Since the sensor readings are directly affected by sensor state, sensor fault diagnosis can be performed by extracting features of the measured signals. This paper proposes a novel fault diagnosis method for sensors based on wavelet entropy. Based on the wavelet theory, wavelet decomposition is utilized to decompose the signal in different scales. Then the instantaneous wavelet energy entropy (IWEE) and instantaneous wavelet singular entropy (IWSE) are defined based on the previous wavelet entropy theory. Subsequently, a fault diagnosis method for gas turbine sensors is proposed based on the results of a numerically simulated example. Then, experiments on this method are carried out on a real micro gas turbine engine. In the experiment, four types of faults with different magnitudes are presented. The experimental results show that the proposed method for sensor fault diagnosis is efficient.

  20. Zinc Oxide-Multi Walled Carbon Nanotubes Nanocomposites for Carbon Monoxide Gas Sensor Application.

    Science.gov (United States)

    Alharbi, Najlaa D; Ansari, M Shahnawaze; Salah, Numan; Khayyat, Suzan A; Khan, Zishan H

    2016-01-01

    Zinc oxide (ZnO)/multi walled carbon nanotubes (MWCNTs) composites based sensors with different ZnO concentrations were fabricated to improve carbon monoxide (CO) gas sensing properties in comparison to the sensors based on bare MWCNTs. To study the structure, morphology and elemental composition of the resultant products, X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM) and Energy dispersive X-ray spectroscopy (EDS) were carried out. It has been observed that as the concentration of ZnO is increased more and more ZnO nanoparticles in the form of nodes get attached to MWCNTs resulting the reduction in average diameter of MWCNTs. The typical response of ZnO/MWCNTs composites based gas sensors for different CO concentrations (40, 100, 140 and 200 ppm) was studied by using very advanced sensing setup attached to I-V measurement system. Different sensing parameters such as: resistive response, sensitivity and response time were estimated at room temperature for all the fabricated sensors. The results indicated that the sensor based on nanocomposite which has 30 mg ZnO dispersed on 20 mg MWCNTs showing highest sensitivity and fastest response. All the sensors showed response times ranging from 8 to 23 seconds. The sensing mechanism behind the sensors based on ZnO/MWCNTs nanocomposites for CO gas at room temperature is also discussed in the present report.