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Sample records for micro structures sensors

  1. Micro- and nano-structure based oligonucleotide sensors.

    PubMed

    Ferrier, David C; Shaver, Michael P; Hands, Philip J W

    2015-06-15

    This paper presents a review of micro- and nano-structure based oligonucleotide detection and quantification techniques. The characteristics of such devices make them very attractive for Point-of-Care or On-Site-Testing biosensing applications. Their small scale means that they can be robust and portable, their compatibility with modern CMOS electronics means that they can easily be incorporated into hand-held devices and their suitability for mass production means that, out of the different approaches to oligonucleotide detection, they are the most suitable for commercialisation. This review discusses the advantages of micro- and nano-structure based sensors and covers the various oligonucleotide detection techniques that have been developed to date. These include: Bulk Acoustic Wave and Surface Acoustic Wave devices, micro- and nano-cantilever sensors, gene Field Effect Transistors, and nanowire and nanopore based sensors. Oligonucleotide immobilisation techniques are also discussed.

  2. Micro-structured femtosecond laser assisted FBG hydrogen sensor.

    PubMed

    Karanja, Joseph Muna; Dai, Yutang; Zhou, Xian; Liu, Bin; Yang, Minghong

    2015-11-30

    We discuss hydrogen sensors based on fiber Bragg gratings (FBGs) micro-machined by femtosecond laser to form microgrooves and sputtered with Pd/Ag composite film. The atomic ratio of the two metals is controlled at Pd:Ag = 3:1. At room temperature, the hydrogen sensitivity of the sensor probe micro-machined by 75 mW laser power and sputtered with 520 nm of Pd/Ag film is 16.5 pm/%H. Comparably, the standard FBG hydrogen sensitivity becomes 2.5 pm/%H towards the same 4% hydrogen concentration. At an ambient temperature of 35°C, the processed sensor head has a dramatic rise in hydrogen sensitivity. Besides, the sensor shows good response and repeatability during hydrogen concentration test. PMID:26698733

  3. Overview of the Characteristics of Micro- and Nano-Structured Surface Plasmon Resonance Sensors

    PubMed Central

    Roh, Sookyoung; Chung, Taerin; Lee, Byoungho

    2011-01-01

    The performance of bio-chemical sensing devices has been greatly improved by the development of surface plasmon resonance (SPR) based sensors. Advancements in micro- and nano-fabrication technologies have led to a variety of structures in SPR sensing systems being proposed. In this review, SPR sensors (from typical Kretschmann prism configurations to fiber sensor schemes) with micro- or nano-structures for local light field enhancement, extraordinary optical transmission, interference of surface plasmon waves, plasmonic cavities, etc. are discussed. We summarize and compare their performances and present guidelines for the design of SPR sensors. PMID:22319369

  4. Platinum Micro-Hotplates on Thermal Insulated Structure for Micro-Thermoelectric Gas Sensor

    NASA Astrophysics Data System (ADS)

    Houlet, Lionel Fabrice; Tajima, Kazuki; Shin, Woosuck; Itoh, Toshio; Izu, Noriya; Matsubara, Ichiro

    In this paper, we investigate the properties of platinum heater micro-hotplates built on a thin dielectric membrane and used for the catalytic combustion of hydrogen in a micro-thermoelectric hydrogen gas sensor. The response of the micro-hotplates was studied with different working temperatures and a response time below 95 ms was determined at a working temeprature of 350°C. It's shown that the fabricated micro-hotplates can bear temperature as high as 600°C. Temperature measurements were carried out with an infrared camera and show an extremely sharp response of the catalyst to the temperature raise with a response time of less than 1s. The response of the hydrogen gas sensor fabricated with these micro-hotplates is reported at different temperature and for 1 v/v % hydrogen in air. The performance of the gas sensor is also examined with and without a micro-hotplate heat spreader located below the membrane. For a 70-μm-thick heat spreader, the heat dispersion from the membrane is enhanced. However, the hydrogen response of the gas sensor with the heat spreader is reduced 1/3 of the sensor without the heat spreader though the temperature distribution is more uniform below the catalyst.

  5. A novel Michelson Fabry-Perot hybrid interference sensor based on the micro-structured fiber

    NASA Astrophysics Data System (ADS)

    Zhang, Yaxun; Zhang, Yu; Wang, Zhenzhen; Liu, Zhihai; Wei, Yong; Zhao, Enming; Yang, Xinghua; Zhang, Jianzhong; Yang, Jun; Yuan, Libo

    2016-09-01

    We propose and demonstrate a novel Michelson Fabry-Perot hybrid fiber interference sensor. By integrating a Michelson interferometer in a two-core fiber and a Fabry-Perot interferometer in a micro silica-capillary, we produce the Michelson Fabry-Perot hybrid interference sensor. Owing to the structure characteristic of the micro-structured fiber, this hybrid fiber interference sensor can achieve the measurement of the axial strain and radial bending simultaneously. The measurement sensitivity of the axial train is 0.015 nm/με and the measurement sensitivity of the radial bending is 1.393 nm/m-1.

  6. Electrochemical micro sensor

    DOEpatents

    Setter, Joseph R.; Maclay, G. Jordan

    1989-09-12

    A micro-amperometric electrochemical sensor for detecting the presence of a pre-determined species in a fluid material is disclosed. The sensor includes a smooth substrate having a thin coating of solid electrolytic material deposited thereon. The working and counter electrodes are deposited on the surface of the solid electrolytic material and adhere thereto. Electrical leads connect the working and counter electrodes to a potential source and an apparatus for measuring the change in an electrical signal caused by the electrochemical oxidation or reduction of the species. Alternatively, the sensor may be fabricated in a sandwich structure and also may be cylindrical, spherical or other shapes.

  7. Dielectric properties modelling of cellular structures with PDMS for micro-sensor applications

    NASA Astrophysics Data System (ADS)

    Kachroudi, Achraf; Basrour, Skandar; Rufer, Libor; Sylvestre, Alain; Jomni, Fathi

    2015-12-01

    Electro-active polymers are emerging in the fields of actuators and micro-sensors because their good dielectric and mechanical properties makes them suitable for such applications. In this work, we focus on micro-structured (cellular) polymer materials (referred as piezoelectrets or ferroelectrets) that need prior charging to attain piezoelectric behaviour. The development of such applications requires an in-depth knowledge of the intrinsic dielectric properties of such structures and models to enable the accurate prediction of a given micro-structured material’s dielectric properties. Various polymers including polypropylene, polytetrafluoroethylene, fluoroethylenepropylene, cyclo-olefines and poly(ethylene terephthalate) in a cellular form have been studied by researchers over the last fifteen years. However, there is still a lack of information on the intrinsic dielectric properties of the most recently used dielectric polymer (polydimethylsiloxane, PDMS) over wide frequency and temperature ranges. In this work, we shall propose an exhaustive equivalent electrical circuit model and explain how it can be used to predict the micro-structured PDMS complex permittivity versus frequency and temperature. The results obtained from the model were found to be in good agreement with experimental data for various micro-structured PDMS materials. Typically, for micro-sensor applications, the dielectric constant and dielectric losses are key factors which need to be minimized. We have developed a configuration which enables both to be strongly reduced with a reduction of 16% in the dielectric constant of a micro-structured PDMS compared with the bulk material. In addition, the phenomena responsible for dielectric losses variations with frequency and temperature are discussed and correlated with the theoretical model. Our model is thus proved to be a powerful tool for the control of the dielectric properties of micro-structured PDMS material for micro-sensor applications.

  8. Fabrication and Characterization of a-Si Micro and Nano-Gap Structure for Electrochemical Sensor

    NASA Astrophysics Data System (ADS)

    Dhahi, Th. S.; Hashim, U.; Ahmed, N. M.; Ali, Md. Eaqub

    2011-05-01

    The development and application of micro gap for electrochemical sensors and biomolecule detection are reviewed in this article. The preparation methods for micro- and nano-gaps and their properties are discussed along with their advantages in electrochemical sensors and biomolecule detection. Biology and medicine have seen great advances in biosensors and biochips capable of characterizing and quantifying electrochemical sensor. To understand the important relationship between sensibility and nano structure, we introduce the fabrication and characterization of micro- and nano-gap structures for electrochemical sensor. In this paper, two mask designs are proposed. The first is the lateral micro- and nano-gap with aluminum (Al) electrode, and the second mask is for pad Al electrode pattern. Lateral micro-gaps are introduced in the fabrication process using amorphous silicon (a-Si) and Al as an electrode. Conventional ultraviolet lithography technique and dry etching for a-Si layer with wet etching for Al surface processes are used to fabricate the micro- and nano-gaps based on the standard complementary metal-oxide-semiconductor technology and characterization of its conductivity. Electrical characterization is applied using Semiconductor Parameter Analyzer, Spectrum Analyzer, current-voltage (IV)-capacitance-voltage (CV) station for electrical characteristics. Conductivity, resistance, and capacitance tests are performed to characterize and verify the structure of the device, resulting in a small micro-gap as revealed by a further IV curve result showing a current in nano amps. The characteristics of the fabricated gap are close to those of a micro-gap, as verified by the literature.

  9. Enhanced Sensitivity of Micro Mechanical Chemical Sensors Through Structural Variation

    SciTech Connect

    Harris, J.C.

    2001-04-16

    Chemical detection devices are very effective; however, their bulkiness makes them undesirable for portable applications. The next generation of chemical detectors is microscopic mechanical devices capable of measuring trace amounts of chemical vapor within the environment. The chemicals do not react directly with the detector, instead intermolecular forces cause chemicals to adhere to the surface. This surface adhesion of the chemical creates surface stress on the detectors leading to measurable movement. Modifications to the structural design of these microstructures have resulted in signal enhancement to over seven hundred percent.

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

    PubMed

    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.

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

    PubMed Central

    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

  12. Application of Micro-Electro-Mechanical Sensors Contactless NDT of Concrete Structures

    PubMed Central

    Ham, Suyun; Popovics, John S.

    2015-01-01

    The utility of micro-electro-mechanical sensors (MEMS) for application in air-coupled (contactless or noncontact) sensing to concrete nondestructive testing (NDT) is studied in this paper. The fundamental operation and characteristics of MEMS are first described. Then application of MEMS sensors toward established concrete test methods, including vibration resonance, impact-echo, ultrasonic surface wave, and multi-channel analysis of surface waves (MASW), is demonstrated. In each test application, the performance of MEMS is compared with conventional contactless and contact sensing technology. Favorable performance of the MEMS sensors demonstrates the potential of the technology for applied contactless NDT efforts. Objective: To illustrate the utility of air-coupled MEMS sensors for concrete NDT, as compared with conventional sensor technology. PMID:25897497

  13. Embedded micro-sensor for monitoring pH in concrete structures

    NASA Astrophysics Data System (ADS)

    Srinivasan, Rengaswamy; Phillips, Terry E.; Bargeron, C. Brent; Carlson, Micah A.; Schemm, Elizabeth R.; Saffarian, Hassan M.

    2000-04-01

    Three major causes of corrosion of steel in concrete are chloride ions (Cl-), temperature (T) and acidity (pH). Under normal operating temperatures and with pH above 13, steel does not undergo pitting corrosion. In presence of Cl-, if the pH decreases below 12, the probability of pitting increases. Acid rain and atmospheric carbon dioxide cause the pH to drop in concrete, often leading to corrosion of the structure with the concomitant cost of repair or replacement. Currently, the pH level in concrete is estimated through destructive testing of the structures. Glass ISFET, and other pH sensors that need maintenance and calibration cannot be embedded in concrete. In this paper, we describe an inexpensive solid state pH sensor that can be embedded in concrete, to detect pH changes at the early stages. It employs a chemical reagent, trinitrobenzenesulfonic acid (TNBS) that exhibits changes in optical properties in the 12 - 14 pH range, and is held in a film of a sol-gel/TNBS composite on an optically transparent surface. A simple LED/filter/photodiode transducer monitors pH-induced changes in TNBS. Such a device needs no periodic calibration or maintenance. The optical window, the light-source and sensor can be easily housed and encapsulated in a chemically inert structure, and embedded in concrete.

  14. Micro-Structured Sapphire Fiber Sensors for Simultaneous Measurements of High-T and Dynamic Gas Pressure in Harsh Environments

    SciTech Connect

    Xiao, Hai; Tsai, Hai-Lung; Dong, Junhang

    2014-09-30

    This is the final report for the program “Micro-Structured Sapphire Fiber Sensors for Simultaneous Measurements of High Temperature and Dynamic Gas Pressure in Harsh Environments”, funded by NETL, and performed by Missouri University of Science and Technology, Clemson University and University of Cincinnati from October 1, 2009 to September 30, 2014. Securing a sustainable energy economy by developing affordable and clean energy from coal and other fossil fuels is a central element to the mission of The U.S. Department of Energy’s (DOE) National Energy Technology Laboratory (NETL). To further this mission, NETL funds research and development of novel sensor technologies that can function under the extreme operating conditions often found in advanced power systems. The main objective of this research program is to conduct fundamental and applied research that will lead to successful development and demonstration of robust, multiplexed, microstructured silica and single-crystal sapphire fiber sensors to be deployed into the hot zones of advanced power and fuel systems for simultaneous measurements of high temperature and gas pressure. The specific objectives of this research program include: 1) Design, fabrication and demonstration of multiplexed, robust silica and sapphire fiber temperature and dynamic gas pressure sensors that can survive and maintain fully operational in high-temperature harsh environments. 2) Development and demonstration of a novel method to demodulate the multiplexed interferograms for simultaneous measurements of temperature and gas pressure in harsh environments. 3) Development and demonstration of novel sapphire fiber cladding and low numerical aperture (NA) excitation techniques to assure high signal integrity and sensor robustness.

  15. Chemical micro-sensor

    DOEpatents

    Ruggiero, Anthony J.

    2005-05-03

    An integrated optical capillary electrophoresis system for analyzing an analyte. A modulated optical pump beam impinges on an capillary containing the analyte/buffer solution which is separated by electrophoresis. The thermally-induced change in the index of refraction of light in said electrophoresis capillary is monitored using an integrated micro-interferometer. The interferometer includes a first interferometer arm intersecting the electrophoresis capillary proximate the excitation beam and a second, reference interferometer arm. Changes in index of refraction in the analyte measured by interrogating the interferometer state using white light interferometry and a phase-generated carrier demodulation technique. Background thermo-optical activity in the buffer solution is cancelled by splitting the pump beam and exciting pure buffer solution in a second section of capillary where it crosses the reference arm of the interferometer.

  16. Self-assembled micro-structured sensors for food safety in paper based food packaging.

    PubMed

    Hakovirta, M; Aksoy, B; Hakovirta, J

    2015-08-01

    Natural self-assembled microstructured particles (diatomaceous earth) were used to develop a gas sensor paper with detection mechanism based on visible and distinct color changes of the sensor paper when exposed to volatile basic nitrogen compounds. The coating formulation for paper was prepared by applying diatomites, polyvinyl alcohol (PVOH), and pH sensitive dyes on acidic paper substrate. The surface coating was designed to allow a maximum gas flow through the diatomite sensors. The produced sensor paper was tested for sensitivity using different ammonia concentrations and we observed a sensitivity lower limit at 63 ppm. As a comparison, the results show comparable sensitivity levels to carbon nanotube based sensor technologies reported in literature.

  17. Micro- and nano-structured metal oxides based chemical sensors: an overview.

    PubMed

    Batra, Ashok K; Chilvery, A K; Guggilla, Padmaja; Aggarwal, Mohan; Currie, James R

    2014-02-01

    This article examines various kinds of chemical sensors, their mechanism of operation and the ways to improve their performance. It reports the results of exploratory investigation of binary composite polycrystalline thick-films such as SnO2-WO3, SnO2-In2O3, and SnO2-ZnO for the detection of volatile organic compound (isopropanol) are reported. It also contains an overview on the status of the new types of metal oxide based nanostructured sensors, such as nano belts, nanorods, nanotubes, nanofibers, nanocomposites, etc.

  18. Micro Sun Sensor for Spacecraft

    NASA Technical Reports Server (NTRS)

    Mobasser, Sohrab; Liebe, Carl; Bae, Youngsam; Schroeder, Jeffrey; Wrigley, Chris

    2004-01-01

    A report describes the development of a compact micro Sun sensor for use as a part of the attitude determination subsystem aboard future miniature spacecraft and planetary robotic vehicles. The prototype unit has a mass of only 9 g, a volume of only 4.2 cm(sup 3), a power consumption of only 30 mW, and a 120 degree field of view. The unit has demonstrated an accuracy of 1 arcminute. The unit consists of a multiple pinhole camera: A micromachined mask containing a rectangular array of microscopic pinholes, machined utilizing the microectromechanical systems (MEMS), is mounted in front of an active-pixel sensor (APS) image detector. The APS consists of a 512 x 512-pixel array, on-chip 10-bit analog to digital converter (ADC), on-chip bias generation, and on-chip timing control for self-sequencing and easy programmability. The digitized output of the APS is processed to compute the centroids of the pinhole Sun images on the APS. The Sun angle, relative to a coordinate system fixed to the sensor unit, is then computed from the positions of the centroids.

  19. Micro sun sensor for spacecraft attitude control

    NASA Technical Reports Server (NTRS)

    Mobasser, Sohrab; Liebe, Carl Christian

    2004-01-01

    A micro sun sensor is being developed for use on a Mars rover for the Mars Science Laboratory Mission. The micro sun sensor, which is basically a small pinhole camera, consists of a small mask with pinholes, placed on top of an image detector.

  20. Chronocoulometry for quantitative control of mass removal in micro-structures and sensors

    NASA Astrophysics Data System (ADS)

    Nowakowski, B. K.; Smith, S. T.; Pratt, J. R.; Shaw, G. A.

    2012-10-01

    In this work, tungsten wires have been etched in a KOH electrolyte solution. Based on the oxidation state of the electrolytic dissolution reaction's product and time integration of the Faradaic current produced during the reaction, this method is capable of providing a direct measurement of the change in mass of a structure from anodic dissolution. To assess the application of this process for controlled mass removal spanning sub-micrograms to milligrams, two experimental studies and accompanying uncertainty analyses have been undertaken. In the first of these, 5 tungsten wires of length 30 mm were used to remove mass values ranging from 50 to 350 μg. Uncertainty estimates indicate relative combined standard uncertainties of less than 0.3% in the mass changes determined from the measurement of Faradaic current. Comparison of the mass change determined using the electrolytic method, and using a precision ultra-microbalance agreed within this uncertainty. The charge-based method was then applied to modify the dynamic characteristics of a quartz tuning fork oscillator. In these experiments, tungsten fiber attached to one tine of the oscillator was etched in 5 μg increments up to 120 μg of total removed mass. In general, frequency shifts of 2.8 Hz.μg-1 were observed, indicating sub-microgram resolution for the characterization of probes based on frequency shift and charge-based mass measurement. Taken together, this study provides the basis for a precision method for determining changes in mass based on electrical measurements from an electrochemical system. The utility of this technique is demonstrated through controlled modification of the dynamic properties of a mechanical oscillator.

  1. Chronocoulometry for quantitative control of mass removal in micro-structures and sensors

    SciTech Connect

    Nowakowski, B. K.; Smith, S. T.; Pratt, J. R.; Shaw, G. A.

    2012-10-15

    In this work, tungsten wires have been etched in a KOH electrolyte solution. Based on the oxidation state of the electrolytic dissolution reaction's product and time integration of the Faradaic current produced during the reaction, this method is capable of providing a direct measurement of the change in mass of a structure from anodic dissolution. To assess the application of this process for controlled mass removal spanning sub-micrograms to milligrams, two experimental studies and accompanying uncertainty analyses have been undertaken. In the first of these, 5 tungsten wires of length 30 mm were used to remove mass values ranging from 50 to 350 {mu}g. Uncertainty estimates indicate relative combined standard uncertainties of less than 0.3% in the mass changes determined from the measurement of Faradaic current. Comparison of the mass change determined using the electrolytic method, and using a precision ultra-microbalance agreed within this uncertainty. The charge-based method was then applied to modify the dynamic characteristics of a quartz tuning fork oscillator. In these experiments, tungsten fiber attached to one tine of the oscillator was etched in 5 {mu}g increments up to 120 {mu}g of total removed mass. In general, frequency shifts of 2.8 Hz{center_dot}{mu}g{sup -1} were observed, indicating sub-microgram resolution for the characterization of probes based on frequency shift and charge-based mass measurement. Taken together, this study provides the basis for a precision method for determining changes in mass based on electrical measurements from an electrochemical system. The utility of this technique is demonstrated through controlled modification of the dynamic properties of a mechanical oscillator.

  2. Flight Qualified Micro Sun Sensor

    NASA Technical Reports Server (NTRS)

    Liebe, Carl Christian; Mobasser, Sohrab; Wrigley, Chris; Schroeder, Jeffrey; Bae, Youngsam; Naegle, James; Katanyoutanant, Sunant; Jerebets, Sergei; Schatzel, Donald; Lee, Choonsup

    2007-01-01

    A prototype small, lightweight micro Sun sensor (MSS) has been flight qualified as part of the attitude-determination system of a spacecraft or for Mars surface operations. The MSS has previously been reported at a very early stage of development in NASA Tech Briefs, Vol. 28, No. 1 (January 2004). An MSS is essentially a miniature multiple-pinhole electronic camera combined with digital processing electronics that functions analogously to a sundial. A micromachined mask containing a number of microscopic pinholes is mounted in front of an active-pixel sensor (APS). Electronic circuits for controlling the operation of the APS, readout from the pixel photodetectors, and analog-to-digital conversion are all integrated onto the same chip along with the APS. The digital processing includes computation of the centroids of the pinhole Sun images on the APS. The spacecraft computer has the task of converting the Sun centroids into Sun angles utilizing a calibration polynomial. The micromachined mask comprises a 500-micron-thick silicon wafer, onto which is deposited a 57-nm-thick chromium adhesion- promotion layer followed by a 200-nm-thick gold light-absorption layer. The pinholes, 50 microns in diameter, are formed in the gold layer by photolithography. The chromium layer is thin enough to be penetrable by an amount of Sunlight adequate to form measurable pinhole images. A spacer frame between the mask and the APS maintains a gap of .1 mm between the pinhole plane and the photodetector plane of the APS. To minimize data volume, mass, and power consumption, the digital processing of the APS readouts takes place in a single field-programmable gate array (FPGA). The particular FPGA is a radiation- tolerant unit that contains .32,000 gates. No external memory is used so the FPGA calculates the centroids in real time as pixels are read off the APS with minimal internal memory. To enable the MSS to fit into a small package, the APS, the FPGA, and other components are mounted

  3. A mechanical micro molecular mass sensor

    PubMed Central

    Kurhekar, A. S.; Apte, P. R.

    2014-01-01

    One of the bio-sensing mechanisms is mechanical. Rather than measuring shift in resonance frequency, we adopt to measure the change in spring constant due to adsorption, as one of the fundamental sensing mechanism. This study explains determination of spring constant of a surface functionalized micro machined micro cantilever, which resonates in a trapezoidal cavity-on Silicon <100> wafer, with the resonating frequency of 7000 cycles per second. This thin-flimsy-oxide micro-cantilever has a typical shape, and the tip of the micro-cantilever is dip-coated with chemically and biologically active material. The change in mass, due to adsorption, is detected by measuring the change in spring constant. The Force-Distance spectroscopy is used to detect the change in spring constant. The experimental results, show that the mechanical sensing scheme used, permit this surface functionalized micro machined micro cantilever to be used as a molecular mass sensor. The mechanical spring behaviour of a micro-cantilever, a micro-mechanical device can be used to develop ultra-tech micro-mechanical system using computer interface. PMID:24459585

  4. Micro-sensor thin-film anemometer

    NASA Technical Reports Server (NTRS)

    Sheplak, Mark (Inventor); McGinley, Catherine B. (Inventor); Spina, Eric F. (Inventor); Stephens, Ralph M. (Inventor); Hopson, Jr., Purnell (Inventor); Cruz, Vincent B. (Inventor)

    1996-01-01

    A device for measuring turbulence in high-speed flows is provided which includes a micro-sensor thin-film probe. The probe is formed from a single crystal of aluminum oxide having a 14.degree. half-wedge shaped portion. The tip of the half-wedge is rounded and has a thin-film sensor attached along the stagnation line. The bottom surface of the half-wedge is tilted upward to relieve shock induced disturbances created by the curved tip of the half-wedge. The sensor is applied using a microphotolithography technique.

  5. Laser ablation for membrane processing of AlGaN/GaN- and micro structured ferroelectric thin film MEMS and SiC pressure sensors for extreme conditions

    NASA Astrophysics Data System (ADS)

    Zehetner, J.; Vanko, G.; Dzuba, J.; Ryger, I.; Lalinsky, T.; Benkler, Manuel; Lucki, Michal

    2015-05-01

    AlGaN/GaN based high electron mobility transistors (HEMTs), Schottky diodes and/or resistors have been presented as sensing devices for mechanical or chemical sensors operating in extreme conditions. In addition we investigate ferroelectric thin films for integration into micro-electro-mechanical-systems (MEMS). Creation of appropriate diaphragms and/or cantilevers out of SiC is necessary for further improvement of sensing properties of such MEMS sensors. For example sensitivity of the AlGaN/GaN based MEMS pressure sensor can be modified by membrane thickness. We demonstrated that a 4H-SiC 80μm thick diaphragms can be fabricated much faster with laser ablation than by electrochemical, photochemical or reactive ion etching (RIE). We were able to verify the feasibility of this process by fabrication of micromechanical membrane structures also in bulk 3C-SiC, borosilicate glass, sapphire and Al2O3 ceramic substrates by femtosecond laser (520nm) ablation. On a 350μm thick 4H-SiC substrate we produced an array of 275μm deep and 1000μm to 3000μm of diameter blind holes without damaging the 2μm AlN layer at the back side. In addition we investigated ferroelectric thin films as they can be deposited and micro-patterned by a direct UV-lithography method after the ablation process for a specific membrane design. The risk to harm or damage the function of thin films was eliminated by that means. Some defects in the ablated membranes are also affected by the polarisation of the laser light. Ripple structures oriented perpendicular to the laser polarisation promote creation of pin holes which would perforate a thin membrane. We developed an ablation technique strongly inhibiting formation of ripples and pin poles.

  6. Micro digital sun sensor with linear detector.

    PubMed

    Fan, Qiao-Yun; Peng, Jia-Wen; Gao, Xin-Yang

    2016-07-01

    In this paper, the design of a novel micro digital sun sensor is described. It relies on V-shaped slit and linear array CCD to measure sun-ray angle against two axes. A highly integrated microprogram control unit) is used to make a very simple and compact system. V-shaped slit can simplify algorithm and achieve a wider field of view. Error compensation and accurate calibration are employed to improve accuracy. Adaptive threshold and adjustable expose time further improve reliability. Experiments and flight validation show that the FOV (Field of View) of the sun sensor is ±65°  ×   ± 65° and the accuracy is 0.1° in the whole FOV. It can work reliably at an update rate of 25 Hz, while the consumption is only 200 mW. This sun sensor is proved to have a good prospect in micro/nanosatellites.

  7. Micro digital sun sensor with linear detector

    NASA Astrophysics Data System (ADS)

    Fan, Qiao-yun; Peng, Jia-wen; Gao, Xin-yang

    2016-07-01

    In this paper, the design of a novel micro digital sun sensor is described. It relies on V-shaped slit and linear array CCD to measure sun-ray angle against two axes. A highly integrated microprogram control unit) is used to make a very simple and compact system. V-shaped slit can simplify algorithm and achieve a wider field of view. Error compensation and accurate calibration are employed to improve accuracy. Adaptive threshold and adjustable expose time further improve reliability. Experiments and flight validation show that the FOV (Field of View) of the sun sensor is ±65° × ± 65° and the accuracy is 0.1° in the whole FOV. It can work reliably at an update rate of 25 Hz, while the consumption is only 200 mW. This sun sensor is proved to have a good prospect in micro/nanosatellites.

  8. Micro digital sun sensor with linear detector.

    PubMed

    Fan, Qiao-Yun; Peng, Jia-Wen; Gao, Xin-Yang

    2016-07-01

    In this paper, the design of a novel micro digital sun sensor is described. It relies on V-shaped slit and linear array CCD to measure sun-ray angle against two axes. A highly integrated microprogram control unit) is used to make a very simple and compact system. V-shaped slit can simplify algorithm and achieve a wider field of view. Error compensation and accurate calibration are employed to improve accuracy. Adaptive threshold and adjustable expose time further improve reliability. Experiments and flight validation show that the FOV (Field of View) of the sun sensor is ±65°  ×   ± 65° and the accuracy is 0.1° in the whole FOV. It can work reliably at an update rate of 25 Hz, while the consumption is only 200 mW. This sun sensor is proved to have a good prospect in micro/nanosatellites. PMID:27475588

  9. Micro-miniature roll rate sensor

    NASA Astrophysics Data System (ADS)

    Grant, Jonathan; Nelson, Bruce; Garnes, George

    1989-11-01

    The Phase 2 Micro-Miniature Roll Rate Sensor Program developed an optical centripetal accelerometer that can be tailored to work over a wide range of accelerations. A rate sensing device was developed by measuring centripetal acceleration due to rotation with a proof mass loading a photoelastic sensing element. The acceleration is proportional to the amount of birefringence induced by the load. Development of this technology resulted in construction of a prototype rate sensor targeted for use with the Copperhead munition. The sensors developed in this program can be adjusted for the desired range of operation through changes in width of a photoelastic (plastic) sensing element and/or changes in the amount of proof mass used to load the sensing element. Radial location of the sensor can also be used to control the range.

  10. Fabrication of a Flexible Micro Temperature Sensor for Micro Reformer Applications

    PubMed Central

    Lee, Chi-Yuan; Lin, Chien-Hen; Lo, Yi-Man

    2011-01-01

    Micro reformers still face obstacles in minimizing their size, decreasing the concentration of CO, conversion efficiency and the feasibility of integrated fabrication with fuel cells. By using a micro temperature sensor fabricated on a stainless steel-based micro reformer, this work attempts to measure the inner temperature and increase the conversion efficiency. Micro temperature sensors on a stainless steel substrate are fabricated using micro-electro-mechanical systems (MEMS) and then placed separately inside the micro reformer. Micro temperature sensors are characterized by their higher accuracy and sensitivity than those of a conventional thermocouple. To the best of our knowledge, micro temperature sensors have not been embedded before in micro reformers and commercial products, therefore, this work presents a novel approach to integrating micro temperature sensors in a stainless steel-based micro reformer in order to evaluate inner local temperature distributions and enhance reformer performance. PMID:22163817

  11. Micro-sensors for space applications

    SciTech Connect

    Butler, M.A.; Frye-Mason, G.C.; Osbourn, G.C.

    1999-12-08

    Important factors in the application of sensing technology to space applications are low mass, small size, and low power. All of these attributes are enabled by the application of MEMS and micro-fabrication technology to microsensors. Two types of sensors are utilized in space applications: remotes sensing from orbit around the earth or another planetary body, and point sensing in the spacecraft or external to it. Several Sandia projects that apply microfabrication technologies to the development of new sensing capabilities having the potential for space applications will be briefly described. The Micro-Navigator is a project to develop a MEMS-based device to measure acceleration and rotation in all three axes for local area navigation. The Polychromator project is a joint project with Honeywell and MIT to develop an electrically programmable diffraction grating that can be programmed to synthesize the spectra of molecules. This grating will be used as the reference cell in a gas correlation radiometer to enable remote chemical detection of most chemical species. Another area of research where microfabrication is having a large impact is the development of a lab on a chip. Sandia's efforts to develop the {mu}ChemLab{trademark} will be described including the development of microfabricated pre-concentrators, chromatographic columns, and detectors. Smart sensors that allow the spacecraft independent decision making capabilities depend on pattern recognition. Sandia's development of a new pattern recognition methodology that can be used to interpret sensor response as well as for target recognition applications will be described.

  12. Integrated Micro-Machined Hydrogen Gas Sensor. Final Report

    SciTech Connect

    Frank DiMeo, Jr.

    2000-10-02

    This report details our recent progress in developing novel MEMS (Micro-Electro-Mechanical Systems) based hydrogen gas sensors. These sensors couple novel thin films as the active layer on a device structure known as a Micro-HotPlate. This coupling has resulted in a gas sensor that has several unique advantages in terms of speed, sensitivity, stability and amenability to large scale manufacture. This Phase-I research effort was focused on achieving the following three objectives: (1) Investigation of sensor fabrication parameters and their effects on sensor performance. (2) Hydrogen response testing of these sensors in wet/dry and oxygen-containing/oxygen-deficient atmospheres. (3) Investigation of the long-term stability of these thin film materials and identification of limiting factors. We have made substantial progress toward achieving each of these objectives, and highlights of our phase I results include the demonstration of signal responses with and without oxygen present, as well as in air with a high level of humidity. We have measured response times of <0.5 s to 1% H{sub 2} in air, and shown the ability to detect concentrations of <200 ppm. These results are extremely encouraging and suggest that this technology has substantial potential for meeting the needs of a hydrogen based economy. These achievements demonstrate the feasibility of using micro-hotplates structures in conjunction with palladium+coated metal-hydride films for sensing hydrogen in many of the environments required by a hydrogen based energy economy. Based on these findings, they propose to continue and expand the development of this technology in Phase II.

  13. Revolution of Sensors in Micro-Electromechanical Systems

    NASA Astrophysics Data System (ADS)

    Esashi, Masayoshi

    2012-08-01

    Microsensors realized by micro-electromechanical systems (MEMS) technology play a key role as the input devices of systems. In this report, the following sensors are reviewed: piezoresistive and capacitive pressure sensors, surface acoustic wave (SAW) wireless pressure sensors, tactile sensor networks for robots, accelerometers, angular velocity sensors (gyroscopes), range image sensors using optical scanners, infrared imagers, chemical sensing systems as Fourier transform infrared (FTIR) spectroscopy and gas chromatography, flow sensors for fluids, and medical sensors such as ultrafine optical-fiber blood pressure sensors and implantable pressure sensors.

  14. CO Sensing Performance of a Micro Thermoelectric Gas Sensor with AuPtPd/SnO₂ Catalyst and Effects of a Double Catalyst Structure with Pt/α-Al₂O₃.

    PubMed

    Goto, Tomoyo; Itoh, Toshio; Akamatsu, Takafumi; Shin, Woosuck

    2015-12-15

    The CO sensing properties of a micro thermoelectric gas sensor (micro-TGS) with a double AuPtPd/SnO₂ and Pt/α-Al₂O₃ catalyst were investigated. While several nanometer sized Pt and Pd particles were uniformly dispersed on SnO₂, the Au particles were aggregated as particles measuring >10 nm in diameter. In situ diffuse reflectance Fourier transform Infrared spectroscopy (DRIFT) analysis of the catalyst showed a CO adsorption peak on Pt and Pd, but no clear peak corresponding to the interaction between CO and Au was detected. Up to 200 °C, CO combustion was more temperature dependent than that of H₂, while H₂ combustion was activated by repeated exposure to H₂ gas during the periodic gas test. Selective CO sensing of the micro-TGS against H₂ was attempted using a double catalyst structure with 0.3-30 wt% Pt/α-Al₂O₃ as a counterpart combustion catalyst. The sensor output of the micro-TGS decreased with increasing Pt content in the Pt/α-Al₂O₃ catalyst, by cancelling out the combustion heat from the AuPtPd/SnO₂ catalyst. In addition, the AuPtPd/SnO₂ and 0.3 wt% Pt/α-Al₂O₃ double catalyst sensor showed good and selective CO detection. We therefore demonstrated that our micro-TGS with double catalyst structure is useful for controlling the gas selectivity of CO against H₂.

  15. Micro Scanning Laser Range Sensor for Planetary Exploration

    NASA Technical Reports Server (NTRS)

    Nakatani, Ichiro; Saito, Hirobumi; Kubota, Takashi; Mizuno, Takahide; Katoh, Hiroshi; Nakamura, Satoru; Kasamura, Kenji; Goto, Hiroshi

    1995-01-01

    This paper proposes a new type of scanning laser range sensor for planetary exploration. The proposed sensor has advantages of small size, light weight, and low power consumption with the help of micro electrical mechanical systems technology. We are in the process of developing a miniature two dimensional optical sensor which is driven by a piezoelectric actuator. In this paper, we present the mechanisms and system concept of a micro scanning laser range sensor.

  16. Micro string resonators as temperature sensors

    NASA Astrophysics Data System (ADS)

    Larsen, T.; Schmid, S.; Boisen, A.

    2013-09-01

    The resonance frequency of strings is highly sensitive to temperature. In this work we have investigated the applicability of micro string resonators as temperature sensors. The resonance frequency of strings is a function of the tensile stress which is coupled to temperature by the thermal expansion of the string and the frame clamping it. The sensitivity improves when the length and pre-stress are reduced and the difference in thermal expansion, Young's modulus and resonant mode are increased. At low tensile stress, the sensitivity becomes highly dependent on temperature. The investigation was done with silicon rich silicon nitride (SiNx), nickel (Ni) and aluminum (Al) micro strings. Aluminum strings show a relative sensitivity of up to 15±1 %/°C, which is more than 100 times higher than values reported by other groups for similar devices. Sub-millisecond time constants can be achieved due to the low thermal mass of the strings. A temperature resolution of 2.5×10-4 °C has been achieved with silicon nitride strings. The theoretical limit for the temperature resolution of 8×10-8 °C has not been reached yet and requires further improvement of the sensor.

  17. Hair-based sensors for micro-autonomous systems

    NASA Astrophysics Data System (ADS)

    Sadeghi, Mahdi M.; Peterson, Rebecca L.; Najafi, Khalil

    2012-06-01

    We seek to harness microelectromechanical systems (MEMS) technologies to build biomimetic devices for low-power, high-performance, robust sensors and actuators on micro-autonomous robot platforms. Hair is used abundantly in nature for a variety of functions including balance and inertial sensing, flow sensing and aerodynamic (air foil) control, tactile and touch sensing, insulation and temperature control, particle filtering, and gas/chemical sensing. Biological hairs, which are typically characterized by large surface/volume ratios and mechanical amplification of movement, can be distributed in large numbers over large areas providing unprecedented sensitivity, redundancy, and stability (robustness). Local neural transduction allows for space- and power-efficient signal processing. Moreover by varying the hair structure and transduction mechanism, the basic hair form can be used for a wide diversity of functions. In this paper, by exploiting a novel wafer-level, bubble-free liquid encapsulation technology, we make arrays of micro-hydraulic cells capable of electrostatic actuation and hydraulic amplification, which enables high force/high deflection actuation and extremely sensitive detection (sensing) at low power. By attachment of cilia (hair) to the micro-hydraulic cell, air flow sensors with excellent sensitivity (< few cm/s) and dynamic range (> 10 m/s) have been built. A second-generation design has significantly reduced the sensor response time while maintaining sensitivity of about 2 cm/s and dynamic range of more than 15 m/s. These sensors can be used for dynamic flight control of flying robots or for situational awareness in surveillance applications. The core biomimetic technologies developed are applicable to a broad range of sensors and actuators.

  18. Flight Qualified Micro Sun Sensor for Mars Applications

    NASA Technical Reports Server (NTRS)

    Mobasser, Sohrab; Liebe, Carl Christian; Naegle, James; Lee, Choonsup

    2005-01-01

    A Right qualified micro sun sensor is being developed and flight qualified for future Man missions. The micro sun sensor, which Is basically a small pinhole camera, consists of a small mask with pinholes, placed on top of an image detector. Images of the sun are formed on the image detector when the sun illuminates the mask. Image processing is performed in the sun sensor that outputs sun centroids.

  19. Micro-position sensor using faraday effect

    SciTech Connect

    McElfresh, Michael; Lucas, Matthew; Silveira, Joseph P.; Groves, Scott E.

    2007-02-27

    A micro-position sensor and sensing system using the Faraday Effect. The sensor uses a permanent magnet to provide a magnetic field, and a magneto-optic material positioned in the magnetic field for rotating the plane of polarization of polarized light transmitted through the magneto-optic material. The magnet is independently movable relative to the magneto-optic material so as to rotate the plane of polarization of the polarized light as a function of the relative position of the magnet. In this manner, the position of the magnet relative to the magneto-optic material may be determined from the rotated polarized light. The sensing system also includes a light source, such as a laser or LED, for producing polarized light, and an optical fiber which is connected to the light source and to the magneto-optic material at a sensing end of the optical fiber. Processing electronics, such as a polarimeter, are also provided for determining the Faraday rotation of the plane of polarization of the back-reflected polarized light to determine the position of the magnet relative to the sensing end of the optical fiber.

  20. Micro-lens maker equation of a CMOS image sensor

    NASA Astrophysics Data System (ADS)

    Wu, Yang

    2007-09-01

    The demand of a large resolution CMOS image sensor (CIS) in a small package drives the pixel pitch size down to the neighborhood of 2 μm. Double-micro-lens (ML) structure is a promising technology to obtain the high focusing capability required by such a small pixel. In this work, an optical model of a double-ML is derived from the well-known lens maker equation. This model predicts the critical back focal length (BFL) and the effective focal length (EFL) of the double-ML embedded in the Back-End-Of-The-Line (BEOL) stack. Explained by this model, a design guideline is provided to optimize the amount of light collected by the photo diode area for a good quantum efficiency (QE), which is crucial to the sensitivity of the sensor.

  1. Structure of catalase determined by MicroED

    PubMed Central

    Nannenga, Brent L; Shi, Dan; Hattne, Johan; Reyes, Francis E; Gonen, Tamir

    2014-01-01

    MicroED is a recently developed method that uses electron diffraction for structure determination from very small three-dimensional crystals of biological material. Previously we used a series of still diffraction patterns to determine the structure of lysozyme at 2.9 Å resolution with MicroED (Shi et al., 2013). Here we present the structure of bovine liver catalase determined from a single crystal at 3.2 Å resolution by MicroED. The data were collected by continuous rotation of the sample under constant exposure and were processed and refined using standard programs for X-ray crystallography. The ability of MicroED to determine the structure of bovine liver catalase, a protein that has long resisted atomic analysis by traditional electron crystallography, demonstrates the potential of this method for structure determination. DOI: http://dx.doi.org/10.7554/eLife.03600.001 PMID:25303172

  2. Structure of catalase determined by MicroED.

    PubMed

    Nannenga, Brent L; Shi, Dan; Hattne, Johan; Reyes, Francis E; Gonen, Tamir

    2014-01-01

    MicroED is a recently developed method that uses electron diffraction for structure determination from very small three-dimensional crystals of biological material. Previously we used a series of still diffraction patterns to determine the structure of lysozyme at 2.9 Å resolution with MicroED (Shi et al., 2013). Here we present the structure of bovine liver catalase determined from a single crystal at 3.2 Å resolution by MicroED. The data were collected by continuous rotation of the sample under constant exposure and were processed and refined using standard programs for X-ray crystallography. The ability of MicroED to determine the structure of bovine liver catalase, a protein that has long resisted atomic analysis by traditional electron crystallography, demonstrates the potential of this method for structure determination. PMID:25303172

  3. Hydrostatic pressure sensor based on micro-cavities developed by the catastrophic fuse effect

    NASA Astrophysics Data System (ADS)

    Domingues, M. F.; Paixão, T.; Mesquita, E.; Alberto, N.; Antunes, P.; Varum, H.; André, P. S.

    2015-09-01

    In this work, an optical fiber hydrostatic pressure sensor based in Fabry-Perot micro-cavities is presented. These micro structures were generated by the recycling of optical fiber previously damaged by the fiber fuse effect, resulting in a cost effective solution when compared with the traditional methods used to produce similar micro-cavities. The developed sensor was tested for pressures ranging from 20.0 to 190.0 cmH2O and a sensitivity of 53.7 +/- 2.6 pm/cmH2O for hydrostatic pressures below to 100 cmH2O was achieved.

  4. Development of GaN-based micro chemical sensor nodes

    NASA Technical Reports Server (NTRS)

    Son, Kyung-ah; Prokopuk, Nicholas; George, Thomas; Moon, Jeong S.

    2005-01-01

    Sensors based on III-N technology are gaining significant interest due to their potential for monolithic integration of RF transceivers and light sources and the capability of high temperature operations. We are developing a GaN-based micro chemical sensor node for remote detection of chemical toxins, and present electrical responses of AlGaN/GaN HEMT (High Electron Mobility Transistor) sensors to chemical toxins as well as other common gases.

  5. Structural diagnostics using optical fiber sensors

    NASA Astrophysics Data System (ADS)

    Surace, Giuseppe; Chiaradia, Agostino

    1997-11-01

    After establishing the basis for assessing the structural implications of introducing a widespread sensor architecture in laminated composite materials in order to precisely identify and locate damage, the paper addresses the problem of structural diagnostics with a discussion of the development of several optical sensors. The research project will first investigate a passive optical fiber impact sensor to be implemented in the matrix of a composite material used in aeronautic and automotive applications. The senor's operating principle is based on the changes in propagation conditions occurring in a fiber subjected to transverse compression: under these circumstances, structural microdistortions produce local energy losses and hence a reduction in the optical power which propagates in the fiber and can be measured at its opposite end. As optical power losses also take place as a result of micro-bending of the optical fiber's longitudinal axis, a preliminary feasibility study will measure power attenuation versus fiber curve radius as the first step in the development of an optical fiber delamination sensor which locates separations between the layers of a composite material, i.e. debonding of sandwich panel core faces. Finally, an active impact sensor will be developed which uses optical fiber's sensitivity to pressure changes to detect the pressure gradient caused by an approaching vehicle or obstacle. The automotive industry will be able to make strategic use of these sensors, for example by installing them on vehicle sides to active the side airbag in the event of impact or collision.

  6. Micro-Pressure Sensors for Future Mars Missions

    NASA Technical Reports Server (NTRS)

    Catling, David C.

    1996-01-01

    The joint research interchange effort was directed at the following principal areas: u further development of NASA-Ames' Mars Micro-meteorology mission concept as a viable NASA space mission especially with regard to the science and instrument specifications u interaction with the flight team from NASA's New Millennium 'Deep-Space 2' (DS-2) mission with regard to selection and design of micro-pressure sensors for Mars u further development of micro-pressure sensors suitable for Mars The research work undertaken in the course of the Joint Research Interchange should be placed in the context of an ongoing planetary exploration objective to characterize the climate system on Mars. In particular, a network of small probes globally-distributed on the surface of the planet has often been cited as the only way to address this particular science goal. A team from NASA Ames has proposed such a mission called the Micrometeorology mission, or 'Micro-met' for short. Surface pressure data are all that are required, in principle, to calculate the Martian atmospheric circulation, provided that simultaneous orbital measurements of the atmosphere are also obtained. Consequently, in the proposed Micro-met mission a large number of landers would measure barometric pressure at various locations around Mars, each equipped with a micro-pressure sensor. Much of the time on the JRI was therefore spent working with the engineers and scientists concerned with Micro-met to develop this particular mission concept into a more realistic proposition.

  7. Micro packaged MEMS pressure sensor for intracranial pressure measurement

    NASA Astrophysics Data System (ADS)

    Xiong, Liu; Yan, Yao; Jiahao, Ma; Yanhang, Zhang; Qian, Wang; Zhaohua, Zhang; Tianling, Ren

    2015-06-01

    This paper presents a micro packaged MEMS pressure sensor for intracranial pressure measurement which belongs to BioMEMS. It can be used in lumbar puncture surgery to measure intracranial pressure. Miniaturization is key for lumbar puncture surgery because the sensor must be small enough to allow it be placed in the reagent chamber of the lumbar puncture needle. The size of the sensor is decided by the size of the sensor chip and package. Our sensor chip is based on silicon piezoresistive effect and the size is 400 × 400 μm2. It is much smaller than the reported polymer intracranial pressure sensors such as liquid crystal polymer sensors. In terms of package, the traditional dual in-line package obviously could not match the size need, the minimal size of recently reported MEMS-based intracranial pressure sensors after packaging is 10 × 10 mm2. In this work, we are the first to introduce a quad flat no-lead package as the package form of piezoresistive intracranial pressure sensors, the whole size of the sensor is minimized to only 3 × 3 mm2. Considering the liquid measurement environment, the sensor is gummed and waterproof performance is tested; the sensitivity of the sensor is 0.9 × 10-2 mV/kPa. Project supported by the National Natural Science Foundation of China (Nos. 61025021, 61434001), and the ‘Thousands Talents’ Program for Pioneer Researchers and Its Innovation Team, China.

  8. Micro-optics technology and sensor systems applications

    NASA Technical Reports Server (NTRS)

    Gal, George; Herman, B.; Anderson, W.; Whitney, R.; Morrow, H.

    1993-01-01

    The current generation of electro-optical sensors utilizing refractive and reflective optical elements require sophisticated, complex, and expensive designs. Advanced-technology-based electro-optical sensors of minimum size and weight require miniaturization of optical, electrical, and mechanical devices with an increasing trend toward integration of various components. Micro-optics technology has the potential in a number of areas to simplify optical design with improved performance. This includes internally cooled apertures, hybrid optical design, microlenses, dispersive multicolor microlenses, active dither, electronically controlled optical beam steer, and microscopic integration of micro-optics, detectors, and signal processing layers. This paper describes our approach to the development of micro-optics technology with our main emphasis for sensors applications.

  9. Sensor technology for smart structures

    NASA Technical Reports Server (NTRS)

    Rogowski, R. S.; Heyman, J. S.; Holben, M. S., Jr.; Dehart, D. W.; Doederlein, T.

    1989-01-01

    Advanced aerospace structures are discussed that will very likely be fabricated with integral sensors, actuators, and microprocessors for monitoring and dynamic control of configuration. The concept of 'smart structures' integrates fiber-optic sensor technology with advanced composite materials, whereby the optical fibers are embedded in a composite material and provide internal sensing capability for monitoring parameters which are important for the safety, performance, and reliability of the material and the structure. Along with other research facilities, NASA has initiated a cooperative program to design, fabricate, and test composite trusses, tubes, and flat panels with embedded optical fibers for testing and developing prototype smart structures. It is shown that fiber-optic sensor technology can be combined with advanced material and structure concepts to produce a new class of materials with internal sensors for health monitoring of structures.

  10. A Micro Pressure Sensor with SU-8 Polymer

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaohong; Yin, Yonghua; Zheng, Xiaohu

    This paper investigated novel wireless RF pressure sensor fabricated with SU-8 polymer. To achieve highly simplified fabrication processes and designs for high-reliable operation, a passive wireless sensors were researched. SU-8 polymer-based micro pressure sensor was fabricated by micro-electro-mechenical system (MEMS) based batch process. The sensor consists of an inductor (L) interconnected with pressure-variable capacitor (C) to form a LC resonant circuit. Fabricated devices measure 4 × 3 mm2 in size and houses 9 turns of Cu electro-plated 100 nH coil. In this system, RF signal was transmitted from external antenna to the fabricated LC resonator. By detecting this abrupt resonant frequency shift of the fabricated device, the pressure change of the device can be measured by wireless method.

  11. Micro-displacement fiber sensor using two-frequency interferometry

    NASA Technical Reports Server (NTRS)

    Tedjojuwono, Ken K.

    1991-01-01

    A He-Ne Zeeman laser has been utilized as a two-frequency light source in a Michelson-type micro-displacement fiber sensor. A polarization maintaining fiber has been installed in the sensing arm, which facilitates flexibility and allows the sensing region to be remotely located. This fiber sensing arm is arranged to replace a quarterwave plate component. The fiber sensor system has a resolution of half a micrometer.

  12. Method of Forming Micro-Sensor Thin-Film Anemometer

    NASA Technical Reports Server (NTRS)

    Sheplak, Mark (Inventor); McGinley, Catherine B. (Inventor); Spina, Eric F. (Inventor); Stephens, Ralph M. (Inventor); Hopson, Purnell, Jr. (Inventor); Cruz, Vincent B. (Inventor)

    2000-01-01

    A device for measuring turbulence in high-speed flows is provided which includes a micro- sensor thin-film probe. The probe is formed from a single crystal of aluminum oxide having a 14 deg half-wedge shaped portion. The tip of the half-wedge is rounded and has a thin-film sensor attached along the stagnation line. The bottom surface of the half-wedge is tilted upward to relieve shock induced disturbances created by the curved tip of the half-wedge. The sensor is applied using a microphotolithography technique.

  13. Fabrication of a Flexible Micro CO Sensor for Micro Reformer Applications

    PubMed Central

    Lee, Chi-Yuan; Chang, Chi-Chung; Lo, Yi-Man

    2010-01-01

    Integration of a reformer and a proton exchange membrane fuel cell (PEMFC) is problematic due to the presence in the gas from the reforming process of a slight amount of carbon monoxide. Carbon monoxide poisons the catalyst of the proton exchange membrane fuel cell subsequently degrading the fuel cell performance, and necessitating the sublimation of the reaction gas before supplying to fuel cells. Based on the use of micro-electro-mechanical systems (MEMS) technology to manufacture flexible micro CO sensors, this study elucidates the relation between a micro CO sensor and different SnO2 thin film thicknesses. Experimental results indicate that the sensitivity increases at temperatures ranging from 100–300 °C. Additionally, the best sensitivity is obtained at a specific temperature. For instance, the best sensitivity of SnO2 thin film thickness of 100 nm at 300 °C is 59.3%. Moreover, a flexible micro CO sensor is embedded into a micro reformer to determine the CO concentration in each part of a micro reformer in the future, demonstrating the inner reaction of a micro reformer in depth and immediate detection. PMID:22163494

  14. A Micro Aerosol Sensor for the Measurement of Airborne Ultrafine Particles.

    PubMed

    Zhang, Chao; Zhu, Rong; Yang, Wenming

    2016-01-01

    Particle number concentration and particle size are the two key parameters used to characterize exposure to airborne nanoparticles or ultrafine particles that have attracted the most attention. This paper proposes a simple micro aerosol sensor for detecting the number concentration and particle size of ultrafine particles with diameters from 50 to 253 nm based on electrical diffusion charging. The sensor is composed of a micro channel and a couple of planar electrodes printed on two circuit boards assembled in parallel, which thus integrate charging, precipitating and measurement elements into one chip, the overall size of which is 98 × 38 × 25 mm³. The experiment results demonstrate that the sensor is useful for measuring monodisperse aerosol particles with number concentrations from 300 to 2.5 × 10⁴ /cm³ and particle sizes from 50 to 253 nm. The aerosol sensor has a simple structure and small size, which is favorable for use in handheld devices. PMID:26999156

  15. A Micro Aerosol Sensor for the Measurement of Airborne Ultrafine Particles

    PubMed Central

    Zhang, Chao; Zhu, Rong; Yang, Wenming

    2016-01-01

    Particle number concentration and particle size are the two key parameters used to characterize exposure to airborne nanoparticles or ultrafine particles that have attracted the most attention. This paper proposes a simple micro aerosol sensor for detecting the number concentration and particle size of ultrafine particles with diameters from 50 to 253 nm based on electrical diffusion charging. The sensor is composed of a micro channel and a couple of planar electrodes printed on two circuit boards assembled in parallel, which thus integrate charging, precipitating and measurement elements into one chip, the overall size of which is 98 × 38 × 25 mm3. The experiment results demonstrate that the sensor is useful for measuring monodisperse aerosol particles with number concentrations from 300 to 2.5 × 104 /cm3 and particle sizes from 50 to 253 nm. The aerosol sensor has a simple structure and small size, which is favorable for use in handheld devices. PMID:26999156

  16. Carbon nanotubes on polymer-based pressure micro-sensor for manometric catheters

    NASA Astrophysics Data System (ADS)

    Teng, M. F.; Hariz, A.; Hsu, H. Y.; Omari, T.

    2008-12-01

    In this paper we investigate the fabrication process of a novel polymer based pressure micro-sensor for use in manometric measurements in medical diagnostics. Review and analysis of polymer materials properties and polymer based sensors has been carried out and has been reported by us elsewhere [1]. The interest in developing a novel polymer based flexible pressure micro-sensor was motivated by the numerous problems inherent in the currently available manometric catheters used in the hospitals. The most critical issue regarding existing catheters was the running and maintenance costs [2]. Thus expensive operation costs lead to reuse of the catheters, which increase the risk for disease transmission. The novel flexible polymer based pressure micro-sensor was build using SU-8, which is a special kind of negative photoresist. Single-walled carbon nanotubes (SWCNTs) and aluminum are used as the sensing material and contacting electrodes respectively. The pressure sensor diaphragm was first patterned on top of an oxidized silicon wafer using SU-8, followed by aluminum deposition to define the electrodes. The carbon nanotube is then deposited using dielectrophoresis (DEP) process. Once the carbon nanotubes are aligned in between these electrodes, the remaining of the sensor structure is formed using SU-8. Patterning of SU-8 and release from the substrate make the device ready for further testing of sensing ability. This research not only investigates the use of polymeric materials to build pressure sensors, but also explores the feasibility of full utilization of polymeric materials to replace conventional silicon materials in micro-sensors fabrication for use in medical environments. The completed sensor is expected to form an integral part of a large versatile sensing system. For example, the biocompatible artificial skin, is predicted to be capable of sensing force, pressure, temperature, and humidity, and may be used in such applications as medical and robotic system.

  17. Fabrication and Characterization of a Micro Methanol Sensor Using the CMOS-MEMS Technique

    PubMed Central

    Fong, Chien-Fu; Dai, Ching-Liang; Wu, Chyan-Chyi

    2015-01-01

    A methanol microsensor integrated with a micro heater manufactured using the complementary metal oxide semiconductor (CMOS)-microelectromechanical system (MEMS) technique was presented. The sensor has a capability of detecting low concentration methanol gas. Structure of the sensor is composed of interdigitated electrodes, a sensitive film and a heater. The heater located under the interdigitated electrodes is utilized to provide a working temperature to the sensitive film. The sensitive film prepared by the sol-gel method is tin dioxide doped cadmium sulfide, which is deposited on the interdigitated electrodes. To obtain the suspended structure and deposit the sensitive film, the sensor needs a post-CMOS process to etch the sacrificial silicon dioxide layer and silicon substrate. The methanol senor is a resistive type. A readout circuit converts the resistance variation of the sensor into the output voltage. The experimental results show that the methanol sensor has a sensitivity of 0.18 V/ppm. PMID:26512671

  18. Fabrication and Characterization of a Micro Methanol Sensor Using the CMOS-MEMS Technique.

    PubMed

    Fong, Chien-Fu; Dai, Ching-Liang; Wu, Chyan-Chyi

    2015-10-23

    A methanol microsensor integrated with a micro heater manufactured using the complementary metal oxide semiconductor (CMOS)-microelectromechanical system (MEMS) technique was presented. The sensor has a capability of detecting low concentration methanol gas. Structure of the sensor is composed of interdigitated electrodes, a sensitive film and a heater. The heater located under the interdigitated electrodes is utilized to provide a working temperature to the sensitive film. The sensitive film prepared by the sol-gel method is tin dioxide doped cadmium sulfide, which is deposited on the interdigitated electrodes. To obtain the suspended structure and deposit the sensitive film, the sensor needs a post-CMOS process to etch the sacrificial silicon dioxide layer and silicon substrate. The methanol senor is a resistive type. A readout circuit converts the resistance variation of the sensor into the output voltage. The experimental results show that the methanol sensor has a sensitivity of 0.18 V/ppm.

  19. Fabrication and Characterization of a Micro Methanol Sensor Using the CMOS-MEMS Technique.

    PubMed

    Fong, Chien-Fu; Dai, Ching-Liang; Wu, Chyan-Chyi

    2015-01-01

    A methanol microsensor integrated with a micro heater manufactured using the complementary metal oxide semiconductor (CMOS)-microelectromechanical system (MEMS) technique was presented. The sensor has a capability of detecting low concentration methanol gas. Structure of the sensor is composed of interdigitated electrodes, a sensitive film and a heater. The heater located under the interdigitated electrodes is utilized to provide a working temperature to the sensitive film. The sensitive film prepared by the sol-gel method is tin dioxide doped cadmium sulfide, which is deposited on the interdigitated electrodes. To obtain the suspended structure and deposit the sensitive film, the sensor needs a post-CMOS process to etch the sacrificial silicon dioxide layer and silicon substrate. The methanol senor is a resistive type. A readout circuit converts the resistance variation of the sensor into the output voltage. The experimental results show that the methanol sensor has a sensitivity of 0.18 V/ppm. PMID:26512671

  20. Micro-optical Distributed Sensors for Aero Propulsion Applications

    NASA Technical Reports Server (NTRS)

    Arnold, S.; Otugen, V.; Seasholtz, Richard G. (Technical Monitor)

    2003-01-01

    The objective of this research is to develop micro-opto-mechanical system (MOMS)-based sensors for time- and space-resolved measurements of flow properties in aerodynamics applications. The measurement technique we propose uses optical resonances in dielectric micro-spheres that can be excited by radiation tunneling from optical fibers. It exploits the tunneling-induced and morphology-dependent shifts in the resonant frequencies. The shift in the resonant frequency is dependent on the size, shape, and index of refraction of the micro-sphere. A physical change in the environment surrounding a micro-bead can change one or more of these properties of the sphere thereby causing a shift in frequency of resonance. The change of the resonance frequency can be detected with high resolution by scanning a frequency-tunable laser that is coupled into the fiber and observing the transmission spectrum at the output of the fiber. It is expected that, in the future, the measurement concept will lead to a system of distributed micro-sensors providing spatial data resolved in time and space. The present project focuses on the development and demonstration of temperature sensors using the morphology-dependent optical resonances although in the latter part of the work, we will also develop a pressure sensor. During the period covered in this report, the optical and electronic equipment necessary for the experimental work was assembled and the experimental setup was designed for the single sensor temperature measurements. Software was developed for real-time tracking of the optical resonance shifts. Some preliminary experiments were also carried out to detect temperature using a single bead in a water bath.

  1. Demonstration of a refractometric sensor based on an optical micro-fiber three-beam interferometer

    PubMed Central

    Han, Chunyang; Ding, Hui; Lv, Fangxing

    2014-01-01

    With diameter close to the wavelength of the guided light and high index contrast between the fiber and the surrounding, an optical micro-fiber shows a variety of interesting waveguiding properties, including widely tailorable optical confinement, strong evanescent fields and waveguide dispersion. Among various micro-fiber applications, optical sensing has been attracting increasing research interest due to its possibilities of realizing miniaturized fiber optic sensors with small footprint, high sensitivity, and low optical power consumption. Typical micro-fiber based sensing structures, including Michelson interferometer, Mach-Zenhder interferometer, Fabry-Perot interferometer, micro-fiber ring resonator, have been proposed. The sensitivity of these structures heavily related to the fraction of evanescent field outside micro-fiber. In this paper, we report the first theoretical and experimental study of a new type of refractometric sensor based on micro-fiber three-beam interferometer. Theoretical and experimental analysis reveals that the sensitivity is not only determined by the fraction of evanescent field outside the micro-fiber but also related to the values of interferometric arms. The sensitivity can be enhanced significantly when the effective lengths of the interferometric arms tends to be equal. We argue that this has great potential for increasing the sensitivity of refractive index detection. PMID:25511687

  2. Innovative smart micro sensors for Army weaponry applications

    NASA Astrophysics Data System (ADS)

    Ruffin, Paul B.; Brantley, Christina; Edwards, Eugene

    2008-03-01

    Micro sensors offer the potential solution to cost, size, and weight issues associated with smart networked sensor systems designed for environmental/missile health monitoring and rocket out-gassing/fuel leak detection, as well as situational awareness on the battlefield. In collaboration with the University of Arkansas (Fayetteville), University of Alabama (Tuscaloosa and Birmingham), Alabama A&M University (Normal), and Streamline Automation (Huntsville, AL), scientists and engineers at the Army Aviation & Missile Research, Development, and Engineering Center (AMRDEC) are investigating several nano-based technologies to solve the problem of sensing extremely small levels of toxic gases associated with both chemical warfare agents (in air and liquids) and potential rocket motor leaks. Innovative techniques are being devised to adapt voltammetry, which is a well established technique for the detection and quantification of substances dissolved in liquids, to low-cost micro sensors for detecting airborne chemical agents and potential missile propellant leakages. In addition, a surface enhanced Raman scattering (SERS) technique, which enhances Raman scattered light by excitation of surface plasmons on nanoporous metal surfaces (nanospheres), is being investigated to develop novel smart sensors for the detection of chemical agents (including rocket motor out-gassing) and potential detection of home-made explosive devices. In this paper, results are delineated that are associated with experimental studies, which are conducted for the aforementioned cases and for several other nano-based technology approaches. The design challenges of each micro sensor technology approach are discussed. Finally, a comparative analysis of the various innovative micro-sensor techniques is provided.

  3. A novel air flow sensor from printed PEDOT micro-hairs

    NASA Astrophysics Data System (ADS)

    Parcell, J.; Aydemir, N.; Devaraj, H.; Travas-Sejdic, J.; Williams, D. E.; Aw, K. C.

    2013-11-01

    We report the creation of a low flow rate sensor from PEDOT micro-hairs. The hairs are printed as pipette-defined depositions using a nanopositioning system. The printing technique was developed for fabricating structures in 2D and 3D. Here micro-hairs with diameters of 4.4 μm were repeatedly extruded with constant heights. These hairs were then applied to produce a prototype flow rate sensor, which was shown to detect flows of 3.5 l min-1. Structural analysis was performed to demonstrate that the design can be modified to potentially observe flows as low as 0.5 l min-1. The results are extended to propose a practical digital flow rate sensor.

  4. CP-OCT sensor guided SMART micro-forceps

    NASA Astrophysics Data System (ADS)

    Song, Cheol; Gehlbach, Peter L.; Kang, Jin U.

    2014-02-01

    Even the most stable hands have unintended movements on the order of 50-100 microns within 0-15 Hz. Micro-forceps are one of the frequently used microsurgical tools used to grasp thin layers of tissue during microsurgery. Here, a handheld Smart Micromanipulation Aided Robotic-surgery Tool (SMART) micro-forceps is developed by integrating a fiber-optic common-path optical coherence tomography (CP-OCT) sensor into the micro-forceps. This forceps design could significantly improve performance by canceling unwanted hand tremor during the moment of a grasping. The basic grasping and peeling functions of the micro-forceps are evaluated in dry phantoms and in a biological tissue model.

  5. Micro-Vibration-Based Slip Detection in Tactile Force Sensors

    PubMed Central

    Fernandez, Raul; Payo, Ismael; Vazquez, Andres S.; Becedas, Jonathan

    2014-01-01

    Tactile sensing provides critical information, such as force, texture, shape or temperature, in manipulation tasks. In particular, tactile sensors traditionally used in robotics are emphasized in contact force determination for grasping control and object recognition. Nevertheless, slip detection is also crucial to successfully manipulate an object. Several approaches have appeared to detect slipping, the majority being a combination of complex sensors with complex algorithms. In this paper, we deal with simplicity, analyzing how a novel, but simple, algorithm, based on micro-vibration detection, can be used in a simple, but low-cost and durable, force sensor. We also analyze the results of using the same principle to detect slipping in other force sensors based on flexible parts. In particular, we show and compare the slip detection with: (i) a flexible finger, designed by the authors, acting as a force sensor; (ii) the finger torque sensor of a commercial robotic hand; (iii) a commercial six-axis force sensor mounted on the wrist of a robot; and (iv) a fingertip piezoresistive matrix sensor. PMID:24394598

  6. Micro-vibration-based slip detection in tactile force sensors.

    PubMed

    Fernandez, Raul; Payo, Ismael; Vazquez, Andres S; Becedas, Jonathan

    2014-01-03

    Tactile sensing provides critical information, such as force, texture, shape or temperature, in manipulation tasks. In particular, tactile sensors traditionally used in robotics are emphasized in contact force determination for grasping control and object recognition. Nevertheless, slip detection is also crucial to successfully manipulate an object. Several approaches have appeared to detect slipping, the majority being a combination of complex sensors with complex algorithms. In this paper, we deal with simplicity, analyzing how a novel, but simple, algorithm, based on micro-vibration detection, can be used in a simple, but low-cost and durable, force sensor. We also analyze the results of using the same principle to detect slipping in other force sensors based on flexible parts. In particular, we show and compare the slip detection with: (i) a flexible finger, designed by the authors, acting as a force sensor; (ii) the finger torque sensor of a commercial robotic hand; (iii) a commercial six-axis force sensor mounted on the wrist of a robot; and (iv) a fingertip piezoresistive matrix sensor.

  7. Fly eye radar or micro-radar sensor technology

    NASA Astrophysics Data System (ADS)

    Molchanov, Pavlo; Asmolova, Olga

    2014-05-01

    To compensate for its eye's inability to point its eye at a target, the fly's eye consists of multiple angularly spaced sensors giving the fly the wide-area visual coverage it needs to detect and avoid the threats around him. Based on a similar concept a revolutionary new micro-radar sensor technology is proposed for detecting and tracking ground and/or airborne low profile low altitude targets in harsh urban environments. Distributed along a border or around a protected object (military facility and buildings, camp, stadium) small size, low power unattended radar sensors can be used for target detection and tracking, threat warning, pre-shot sniper protection and provides effective support for homeland security. In addition it can provide 3D recognition and targets classification due to its use of five orders more pulses than any scanning radar to each space point, by using few points of view, diversity signals and intelligent processing. The application of an array of directional antennas eliminates the need for a mechanical scanning antenna or phase processor. It radically decreases radar size and increases bearing accuracy several folds. The proposed micro-radar sensors can be easy connected to one or several operators by point-to-point invisible protected communication. The directional antennas have higher gain, can be multi-frequency and connected to a multi-functional network. Fly eye micro-radars are inexpensive, can be expendable and will reduce cost of defense.

  8. Flexible Wing Base Micro Aerial Vehicles: Micro Air Vehicles (MAVs) for Surveillance and Remote Sensor Delivery

    NASA Technical Reports Server (NTRS)

    Ifju, Peter

    2002-01-01

    Micro Air Vehicles (MAVs) will be developed for tracking individuals, locating terrorist threats, and delivering remote sensors, for surveillance and chemical/biological agent detection. The tasks are: (1) Develop robust MAV platform capable of carrying sensor payload. (2) Develop fully autonomous capabilities for delivery of sensors to remote and distant locations. The current capabilities and accomplishments are: (1) Operational electric (inaudible) 6-inch MAVs with novel flexible wing, providing superior aerodynamic efficiency and control. (2) Vision-based flight stability and control (from on-board cameras).

  9. Fiber optic micro sensor for the measurement of tendon forces

    PubMed Central

    2012-01-01

    A fiber optic sensor developed for the measurement of tendon forces was designed, numerically modeled, fabricated, and experimentally evaluated. The sensor incorporated fiber Bragg gratings and micro-fabricated stainless steel housings. A fiber Bragg grating is an optical device that is spectrally sensitive to axial strain. Stainless steel housings were designed to convert radial forces applied to the housing into axial forces that could be sensed by the fiber Bragg grating. The metal housings were fabricated by several methods including laser micromachining, swaging, and hydroforming. Designs are presented that allow for simultaneous temperature and force measurements as well as for simultaneous resolution of multi-axis forces. The sensor was experimentally evaluated by hydrostatic loading and in vitro testing. A commercial hydraulic burst tester was used to provide uniform pressures on the sensor in order to establish the linearity, repeatability, and accuracy characteristics of the sensor. The in vitro experiments were performed in excised tendon and in a dynamic gait simulator to simulate biological conditions. In both experimental conditions, the sensor was found to be a sensitive and reliable method for acquiring minimally invasive measurements of soft tissue forces. Our results suggest that this sensor will prove useful in a variety of biomechanical measurements. PMID:23033868

  10. Micro biochemical sensor based on SOI planar optical waveguide

    NASA Astrophysics Data System (ADS)

    Du, Yang; Dong, Ying

    2014-02-01

    A novel biochemical sensor based on planar optical waveguide is presented in this paper. The features of the sensor are as follows, the planar optical waveguide is made of SOI (Silicon-On-Insulator) material, a Mach Zehnder (M-Z) Interferometer structure is adopted as the sensing part, the sensor chip is fabricated using CMOS compatible technology and the size of the sensor chip is on the micron scale. Compared with the traditional biochemical sensors, this new type of sensor has such notable advantages as miniaturization, integration, high sensitivity and strong anti-interference capability, which provide the sensor with potential applications where traditional biochemical sensors cannot be used. At first, the benefits of SOI material comparing to other optical waveguide materials were analyzed in this paper. Then, according to the optical waveguide mode theory, M-Z interferometer waveguide was designed for the single mode behavior. By theoretical analysis of the radiation loss in the Y-junction of the planar waveguide interferometer, the relationship between the branch angle and the radiation loss was obtained. The power transfer function and the parametric equation of sensitivity of the M-Z interferometer were obtained through analysis of the waveguide structure. At last, the resolution of the effective refractive index and the characteristics of sensitivity of the sensor based on SOI M-Z Interferometer waveguide were simulated and analyzed by utilizing MATLAB software. As a result, the sensitivity of SOI M-Z Interferometer sensor can reach the order of 10-7 magnitude.

  11. A high sensitivity humidity sensor based on micro-ring resonator with three coupling points

    NASA Astrophysics Data System (ADS)

    Guo, Shi-liang; Wang, Wen-juan; Hu, Chun-hai

    2014-12-01

    A novel high sensitivity humidity sensor based on micro-ring resonator with three coupling points (MRRTCP) is reported. Since the dielectric constant of Polyimide is highly sensible to the relative humidity of the environment, we choose the Polyimide (PI) as the moisture material. The effective refractive index of the sensing part of the sensor changes as the relative humidity of the environment changes, this leading to an obvious shift of the output spectrum. The sensing range of the relative humidity sensor is 0~100%RH, and the sensitivity is 0.0017μm/%RH, and the structure is relatively simple and could be used in micro-scale humidity sensing.

  12. Silicon Nanotips Antireflection Surface for Micro Sun Sensor

    NASA Technical Reports Server (NTRS)

    Bae, Sam Y.; Lee, Choonsup; Mobasser, Sohrab; Manohara, Harish

    2006-01-01

    We have developed a new technique to fabricate antireflection surface using silicon nano-tips for use on a micro sun sensor for Mars rovers. We have achieved randomly distributed nano-tips of radius spanning from 20 nm to 100 nm and aspect ratio of 200 using a two-step dry etching process. The 30(deg) specular reflectance at the target wavelength of 1 (mu)m is only about 0.09 %, nearly three orders of magnitude lower than that of bare silicon, and the hemispherical reflectance is 8%. By changing the density and aspect ratio of these nanotips, the change in reflectance is demonstrated. Using surfaces covered with these nano-tips, the critical problem of ghost images that are caused by multiple internal reflections in a micro sun sensor was solved.

  13. Analysis of the reflection of a micro drop fiber sensor

    NASA Astrophysics Data System (ADS)

    Sun, Weimin; Liu, Qiang; Zhao, Lei; Li, Yingjuan; Yuan, Libo

    2005-01-01

    Micro drop fiber sensors are effective tools for measuring characters of liquids. These types of sensors are wildly used in biotechnology, beverage and food markets. For a fiber micro drop sensor, the signal of the output light is wavy with two peaks, normally. Carefully analyzing the wavy process can identify the liquid components. Understanding the reason of forming this wavy signal is important to design a suitable sensing head and to choose a suitable signal-processing method. The dripping process of a type of liquids is relative to the characters of the liquid and the shape of the sensing head. The quasi-Gauss model of the light field from the input-fiber end is used to analyse the distribution of the light field in the liquid drop. In addition, considering the characters of the liquid to be measured, the dripping process of the optical signal from the output-fiber end can be expected. The reflection surface of the micro drop varies as serials of spheres with different radiuses and global centers. The intensity of the reflection light changes with the shape of the surface. The varying process of the intensity relates to the tense, refractive index, transmission et al. To support the analyse above, an experimental system is established. In the system, LED is chosen as the light source and the PIN transform the light signal to the electrical signal, which is collected by a data acquisition card. An on-line testing system is made to check the theory discussed above.

  14. Multiplexing of six micro-displacement suspended-core Sagnac interferometer sensors with a Raman-Erbium fiber laser.

    PubMed

    Bravo, Mikel; Fernández-Vallejo, Montserrat; Echapare, Mikel; López-Amo, Manuel; Kobelke, J; Schuster, K

    2013-02-11

    This work experimentally demonstrates a long-range optical fiber sensing network for the multiplexing of fiber sensors based on photonic crystal fibers. Specifically, six photonic crystal fiber sensors which are based on a Sagnac interferometer that includes a suspended-core fiber have been used. These sensors offer a high sensitivity for micro-displacement measurements. The fiber sensor network presents a ladder structure and its operation mode is based on a fiber ring laser which combines Raman and Erbium doped fiber amplification. Thus, we show the first demonstration of photonic crystal fiber sensors for remote measurement applications up to 75 km. PMID:23481755

  15. In2O3-based micro gas sensor for detecting NO x gases

    NASA Astrophysics Data System (ADS)

    Kim, Bum-Joon; Song, In-Gyu; Kim, Jung-Sik

    2014-03-01

    In this study, NO x micro gas sensors for monitoring the indoor atmosphere of automobile were fabricated using MEMS (microelectromechanical system) technology and a sol-gel process. The sensing electrode and micro heater were designed to have a co-planar typed structure in a Pt thin film layer. The thermal characteristics of a micro heater array were analyzed using a finite element method (FEM). The chip size of the gas sensor was approximately 2 mm × 2 mm. Indium oxide as a sensing material for NO x gas was synthesized by a sol-gel process with indium isopropoxide as a precursor. Field emission Scanning electron microscopy and x-ray diffraction showed that particle size of the synthesized In2O3 was approximately 17-45 nm. The maximum gas sensitivity as the relative resistance ( R s = R gas / R air ) was observed at 275°C with a value of 8.0 at 1 ppm NO2 gas. The response (80% saturation) and recovery times were within 1 min. The sensing properties of NO2 gas exhibited linear behavior with increasing gas concentration. The sensing mechanism of the gas sensor was explained by the variations in the electron depletion layers and the adsorption of gas molecules on the In2O3 particle surface. These results suggest that in the future, MEMS-based gas sensors can be used as automotive-exhaust-gas sensors.

  16. Polypyrrole Porous Micro Humidity Sensor Integrated with a Ring Oscillator Circuit on Chip

    PubMed Central

    Yang, Ming-Zhi; Dai, Ching-Liang; Lu, De-Hao

    2010-01-01

    This study presents the design and fabrication of a capacitive micro humidity sensor integrated with a five-stage ring oscillator circuit on chip using the complimentary metal oxide semiconductor (CMOS) process. The area of the humidity sensor chip is about 1 mm2. The humidity sensor consists of a sensing capacitor and a sensing film. The sensing capacitor is constructed from spiral interdigital electrodes that can enhance the sensitivity of the sensor. The sensing film of the sensor is polypyrrole, which is prepared by the chemical polymerization method, and the film has a porous structure. The sensor needs a post-CMOS process to coat the sensing film. The post-CMOS process uses a wet etching to etch the sacrificial layers, and then the polypyrrole is coated on the sensing capacitor. The sensor generates a change in capacitance when the sensing film absorbs or desorbs vapor. The ring oscillator circuit converts the capacitance variation of the sensor into the oscillation frequency output. Experimental results show that the sensitivity of the humidity sensor is about 99 kHz/%RH at 25 °C. PMID:22163459

  17. A Micro-Thermal Sensor for Focal Therapy Applications.

    PubMed

    Natesan, Harishankar; Hodges, Wyatt; Choi, Jeunghwan; Lubner, Sean; Dames, Chris; Bischof, John

    2016-02-26

    There is an urgent need for sensors deployed during focal therapies to inform treatment planning and in vivo monitoring in thin tissues. Specifically, the measurement of thermal properties, cooling surface contact, tissue thickness, blood flow and phase change with mm to sub mm accuracy are needed. As a proof of principle, we demonstrate that a micro-thermal sensor based on the supported "3ω" technique can achieve this in vitro under idealized conditions in 0.5 to 2 mm thick tissues relevant to cryoablation of the pulmonary vein (PV). To begin with "3ω" sensors were microfabricated onto flat glass as an idealization of a focal probe surface. The sensor was then used to make new measurements of 'k' (W/m.K) of porcine PV, esophagus, and phrenic nerve, all needed for PV cryoabalation treatment planning. Further, by modifying the sensor use from traditional to dynamic mode new measurements related to tissue vs. fluid (i.e. water) contact, fluid flow conditions, tissue thickness, and phase change were made. In summary, the in vitro idealized system data presented is promising and warrants future work to integrate and test supported "3ω" sensors on in vivo deployed focal therapy probe surfaces (i.e. balloons or catheters).

  18. A Micro-Thermal Sensor for Focal Therapy Applications

    NASA Astrophysics Data System (ADS)

    Natesan, Harishankar; Hodges, Wyatt; Choi, Jeunghwan; Lubner, Sean; Dames, Chris; Bischof, John

    2016-02-01

    There is an urgent need for sensors deployed during focal therapies to inform treatment planning and in vivo monitoring in thin tissues. Specifically, the measurement of thermal properties, cooling surface contact, tissue thickness, blood flow and phase change with mm to sub mm accuracy are needed. As a proof of principle, we demonstrate that a micro-thermal sensor based on the supported “3ω” technique can achieve this in vitro under idealized conditions in 0.5 to 2 mm thick tissues relevant to cryoablation of the pulmonary vein (PV). To begin with “3ω” sensors were microfabricated onto flat glass as an idealization of a focal probe surface. The sensor was then used to make new measurements of ‘k’ (W/m.K) of porcine PV, esophagus, and phrenic nerve, all needed for PV cryoabalation treatment planning. Further, by modifying the sensor use from traditional to dynamic mode new measurements related to tissue vs. fluid (i.e. water) contact, fluid flow conditions, tissue thickness, and phase change were made. In summary, the in vitro idealized system data presented is promising and warrants future work to integrate and test supported “3ω” sensors on in vivo deployed focal therapy probe surfaces (i.e. balloons or catheters).

  19. A Micro-Thermal Sensor for Focal Therapy Applications

    PubMed Central

    Natesan, Harishankar; Hodges, Wyatt; Choi, Jeunghwan; Lubner, Sean; Dames, Chris; Bischof, John

    2016-01-01

    There is an urgent need for sensors deployed during focal therapies to inform treatment planning and in vivo monitoring in thin tissues. Specifically, the measurement of thermal properties, cooling surface contact, tissue thickness, blood flow and phase change with mm to sub mm accuracy are needed. As a proof of principle, we demonstrate that a micro-thermal sensor based on the supported “3ω” technique can achieve this in vitro under idealized conditions in 0.5 to 2 mm thick tissues relevant to cryoablation of the pulmonary vein (PV). To begin with “3ω” sensors were microfabricated onto flat glass as an idealization of a focal probe surface. The sensor was then used to make new measurements of ‘k’ (W/m.K) of porcine PV, esophagus, and phrenic nerve, all needed for PV cryoabalation treatment planning. Further, by modifying the sensor use from traditional to dynamic mode new measurements related to tissue vs. fluid (i.e. water) contact, fluid flow conditions, tissue thickness, and phase change were made. In summary, the in vitro idealized system data presented is promising and warrants future work to integrate and test supported “3ω” sensors on in vivo deployed focal therapy probe surfaces (i.e. balloons or catheters). PMID:26916460

  20. Micro-reactors for characterization of nanostructure-based sensors

    NASA Astrophysics Data System (ADS)

    Savu, R.; Silveira, J. V.; Flacker, A.; Vaz, A. R.; Joanni, E.; Pinto, A. C.; Gobbi, A. L.; Santos, T. E. A.; Rotondaro, A. L. P.; Moshkalev, S. A.

    2012-05-01

    Fabrication and testing of micro-reactors for the characterization of nanosensors is presented in this work. The reactors have a small volume (100 μl) and are equipped with gas input/output channels. They were machined from a single piece of kovar in order to avoid leaks in the system due to additional welding. The contact pins were electrically insulated from the body of the reactor using a borosilicate sealing glass and the reactor was hermetically sealed using a lid and an elastomeric o-ring. One of the advantages of the reactor lies in its simple assembly and ease of use with any vacuum/gas system, allowing the connection of more than one device. Moreover, the lid can be modified in order to fit a window for in situ optical characterization. In order to prove its versatility, carbon nanotube-based sensors were tested using this micro-reactor. The devices were fabricated by depositing carbon nanotubes over 1 μm thick gold electrodes patterned onto Si/SiO2 substrates. The sensors were tested using oxygen and nitrogen atmospheres, in the pressure range between 10-5 and 10-1 mbar. The small chamber volume allowed the measurement of fast sensor characteristic times, with the sensors showing good sensitivity towards gas and pressure as well as high reproducibility.

  1. Snow Micro-Structure Model

    2014-06-25

    PIKA is a MOOSE-based application for modeling micro-structure evolution of seasonal snow. The model will be useful for environmental, atmospheric, and climate scientists. Possible applications include application to energy balance models, ice sheet modeling, and avalanche forecasting. The model implements physics from published, peer-reviewed articles. The main purpose is to foster university and laboratory collaboration to build a larger multi-scale snow model using MOOSE. The main feature of the code is that it is implementedmore » using the MOOSE framework, thus making features such as multiphysics coupling, adaptive mesh refinement, and parallel scalability native to the application. PIKA implements three equations: the phase-field equation for tracking the evolution of the ice-air interface within seasonal snow at the grain-scale; the heat equation for computing the temperature of both the ice and air within the snow; and the mass transport equation for monitoring the diffusion of water vapor in the pore space of the snow.« less

  2. Snow Micro-Structure Model

    SciTech Connect

    Micah Johnson, Andrew Slaughter

    2014-06-25

    PIKA is a MOOSE-based application for modeling micro-structure evolution of seasonal snow. The model will be useful for environmental, atmospheric, and climate scientists. Possible applications include application to energy balance models, ice sheet modeling, and avalanche forecasting. The model implements physics from published, peer-reviewed articles. The main purpose is to foster university and laboratory collaboration to build a larger multi-scale snow model using MOOSE. The main feature of the code is that it is implemented using the MOOSE framework, thus making features such as multiphysics coupling, adaptive mesh refinement, and parallel scalability native to the application. PIKA implements three equations: the phase-field equation for tracking the evolution of the ice-air interface within seasonal snow at the grain-scale; the heat equation for computing the temperature of both the ice and air within the snow; and the mass transport equation for monitoring the diffusion of water vapor in the pore space of the snow.

  3. Fabrication of conducting polymer micro/nanostructures coated with Au nanoparticles for electrochemical sensors.

    PubMed

    An, Taechang; Choi, WooSeok; Lee, Eunjoo; Cho, Seong J; Lim, Geunbae

    2012-06-01

    Polypyrrole (PPy) micro/nanostructures coated with Au nanoparticles were prepared by electropolymerization and electro-deposition. Two types of PPy structures, micro-embossed and nanowire forest, were synthesized on patterned gold electrodes using different aqueous solutions, and Au nanoparticles were coated onto the PPy micro/nanostructure surface. The size of the Au nanoparticles ranged from 10 to 100 nm, and the maximum density of the nanoparticles was 73 particles/microm2. The small size and high density of the Au nanoparticles were achieved by optimizing the deposition time and chloroauric acid (HAuCl4) concentration. Cyclic voltammograms of ferrocyanide oxidation showed that the PPy micro/nanostructures coated with Au nanoparticles exhibit good electrochemical activity. These high-performance electrodes can be used in electrochemical sensors because the Au nanoparticles enhance electron transfer and provide a binding site for biomarker molecules, such as DNA, protein, and aptamers.

  4. Semi-physical simulation test for micro CMOS star sensor

    NASA Astrophysics Data System (ADS)

    Yang, Jian; Zhang, Guang-jun; Jiang, Jie; Fan, Qiao-yun

    2008-03-01

    A designed star sensor must be extensively tested before launching. Testing star sensor requires complicated process with much time and resources input. Even observing sky on the ground is a challenging and time-consuming job, requiring complicated and expensive equipments, suitable time and location, and prone to be interfered by weather. And moreover, not all stars distributed on the sky can be observed by this testing method. Semi-physical simulation in laboratory reduces the testing cost and helps to debug, analyze and evaluate the star sensor system while developing the model. The test system is composed of optical platform, star field simulator, star field simulator computer, star sensor and the central data processing computer. The test system simulates the starlight with high accuracy and good parallelism, and creates static or dynamic image in FOV (Field of View). The conditions of the test are close to observing real sky. With this system, the test of a micro star tracker designed by Beijing University of Aeronautics and Astronautics has been performed successfully. Some indices including full-sky autonomous star identification time, attitude update frequency and attitude precision etc. meet design requirement of the star sensor. Error source of the testing system is also analyzed. It is concluded that the testing system is cost-saving, efficient, and contributes to optimizing the embed arithmetic, shortening the development cycle and improving engineering design processes.

  5. Geometry optimization for micro-pressure sensor considering dynamic interference.

    PubMed

    Yu, Zhongliang; Zhao, Yulong; Li, Lili; Tian, Bian; Li, Cun

    2014-09-01

    Presented is the geometry optimization for piezoresistive absolute micro-pressure sensor. A figure of merit called the performance factor (PF) is defined as a quantitative index to describe the comprehensive performances of a sensor including sensitivity, resonant frequency, and acceleration interference. Three geometries are proposed through introducing islands and sensitive beams into typical flat diaphragm. The stress distributions of sensitive elements are analyzed by finite element method. Multivariate fittings based on ANSYS simulation results are performed to establish the equations about surface stress, deflection, and resonant frequency. Optimization by MATLAB is carried out to determine the dimensions of the geometries. Convex corner undercutting is evaluated. Each PF of the three geometries with the determined dimensions is calculated and compared. Silicon bulk micromachining is utilized to fabricate the prototypes of the sensors. The outputs of the sensors under both static and dynamic conditions are tested. Experimental results demonstrate the rationality of the defined performance factor and reveal that the geometry with quad islands presents the highest PF of 210.947 Hz(1/4). The favorable overall performances enable the sensor more suitable for altimetry.

  6. Geometry optimization for micro-pressure sensor considering dynamic interference

    SciTech Connect

    Yu, Zhongliang; Zhao, Yulong Li, Lili; Tian, Bian; Li, Cun

    2014-09-15

    Presented is the geometry optimization for piezoresistive absolute micro-pressure sensor. A figure of merit called the performance factor (PF) is defined as a quantitative index to describe the comprehensive performances of a sensor including sensitivity, resonant frequency, and acceleration interference. Three geometries are proposed through introducing islands and sensitive beams into typical flat diaphragm. The stress distributions of sensitive elements are analyzed by finite element method. Multivariate fittings based on ANSYS simulation results are performed to establish the equations about surface stress, deflection, and resonant frequency. Optimization by MATLAB is carried out to determine the dimensions of the geometries. Convex corner undercutting is evaluated. Each PF of the three geometries with the determined dimensions is calculated and compared. Silicon bulk micromachining is utilized to fabricate the prototypes of the sensors. The outputs of the sensors under both static and dynamic conditions are tested. Experimental results demonstrate the rationality of the defined performance factor and reveal that the geometry with quad islands presents the highest PF of 210.947 Hz{sup 1/4}. The favorable overall performances enable the sensor more suitable for altimetry.

  7. Cobalt Oxide Nanosheet and CNT Micro Carbon Monoxide Sensor Integrated with Readout Circuit on Chip

    PubMed Central

    Dai, Ching-Liang; Chen, Yen-Chi; Wu, Chyan-Chyi; Kuo, Chin-Fu

    2010-01-01

    The study presents a micro carbon monoxide (CO) sensor integrated with a readout circuit-on-a-chip manufactured by the commercial 0.35 μm complementary metal oxide semiconductor (CMOS) process and a post-process. The sensing film of the sensor is a composite cobalt oxide nanosheet and carbon nanotube (CoOOH/CNT) film that is prepared by a precipitation-oxidation method. The structure of the CO sensor is composed of a polysilicon resistor and a sensing film. The sensor, which is of a resistive type, changes its resistance when the sensing film adsorbs or desorbs CO gas. The readout circuit is used to convert the sensor resistance into the voltage output. The post-processing of the sensor includes etching the sacrificial layers and coating the sensing film. The advantages of the sensor include room temperature operation, short response/recovery times and easy post-processing. Experimental results show that the sensitivity of the CO sensor is about 0.19 mV/ppm, and the response and recovery times are 23 s and 34 s for 200 ppm CO, respectively. PMID:22294897

  8. Torque sensor having a spoked sensor element support structure

    NASA Technical Reports Server (NTRS)

    Lurie, Boris J. (Inventor); Schier, J. Alan (Inventor)

    1990-01-01

    Piezoelectric sensor devices are attached across pairs of circularly arranged spokes arrayed on the periphery of an annular ring. The sensor devices each include a preloaded steel ball mounting arrangement for mounting a piezoelectric sensor element. A first circular interface plate on one side of the sensor structure attaches to alternate one of the spokes, and a circular interface plate on the opposite side of the same diameter as the first interface plate attaches to the remaining spokes.

  9. Applications of Micro/Nanoparticles in Microfluidic Sensors: A Review

    PubMed Central

    Jiang, Yusheng; Wang, Hui; Li, Shunbo; Wen, Weijia

    2014-01-01

    This paper reviews the applications of micro/nanoparticles in microfluidics device fabrication and analytical processing. In general, researchers have focused on two properties of particles—electric behavior and magnetic behavior. The applications of micro/nanoparticles could be summarized on the chip fabrication level and on the processing level. In the fabrication of microfluidic chips (chip fabrication level), particles are good additives in polydimethylsiloxane (PDMS) to prepare conductive or magnetic composites which have wide applications in sensors, valves and actuators. On the other hand, particles could be manipulated according to their electric and magnetic properties under external electric and magnetic fields when they are travelling in microchannels (processing level). Researchers have made a great progress in preparing modified PDMS and investigating the behaviors of particles in microchannels. This article attempts to present a discussion on the basis of particles applications in microfluidics. PMID:24755517

  10. Applications of micro/nanoparticles in microfluidic sensors: a review.

    PubMed

    Jiang, Yusheng; Wang, Hui; Li, Shunbo; Wen, Weijia

    2014-01-01

    This paper reviews the applications of micro/nanoparticles in microfluidics device fabrication and analytical processing. In general, researchers have focused on two properties of particles--electric behavior and magnetic behavior. The applications of micro/nanoparticles could be summarized on the chip fabrication level and on the processing level. In the fabrication of microfluidic chips (chip fabrication level), particles are good additives in polydimethylsiloxane (PDMS) to prepare conductive or magnetic composites which have wide applications in sensors, valves and actuators. On the other hand, particles could be manipulated according to their electric and magnetic properties under external electric and magnetic fields when they are travelling in microchannels (processing level). Researchers have made a great progress in preparing modified PDMS and investigating the behaviors of particles in microchannels. This article attempts to present a discussion on the basis of particles applications in microfluidics. PMID:24755517

  11. Micro Electro-Mechanical System (MEMS) Pressure Sensor for Footwear

    DOEpatents

    Kholwadwala, Deepesh K.; Rohrer, Brandon R.; Spletzer, Barry L.; Galambos, Paul C.; Wheeler, Jason W.; Hobart, Clinton G.; Givler, Richard C.

    2008-09-23

    Footwear comprises a sole and a plurality of sealed cavities contained within the sole. The sealed cavities can be incorporated as deformable containers within an elastic medium, comprising the sole. A plurality of micro electro-mechanical system (MEMS) pressure sensors are respectively contained within the sealed cavity plurality, and can be adapted to measure static and dynamic pressure within each of the sealed cavities. The pressure measurements can provide information relating to the contact pressure distribution between the sole of the footwear and the wearer's environment.

  12. Data Processing from Micro-Plasma Gas Analytical Sensor

    NASA Astrophysics Data System (ADS)

    Mustafaev, Alexander; Tsyganov, Alexander

    2011-10-01

    Theoretical consideration of signal formation at micro-plasma gas analyzer based on Collisional Electron Spectroscopy (CES) and experimental results on CES sensor are presented. It is demonstrated that a diffusion path confinement for characteristic electrons provides a possibility to measure electrons energy distribution function (EEDF) and to find characteristic spectra of species at high (up to atmospheric) gas pressure. Simple micro-plasma CES sensor of two plane parallel electrode configuration with current-voltage measurement in afterglow discharge may be operated in two possible modes. The first mode presumes application of classic 2-nd derivative of current-voltage curve to select characteristic peaks in electron energy spectra of the species to be detected. In the case of a deeper collisional dissipation of characteristic peaks, a 3-rd derivative may be used. Said derivatives were obtained by differentiating of a spline providing least-squares approximation of current-voltage curve. Model and experimental electron energy spectra of pair He metastables collisions in dependence of inter-electrode gap are discussed. Theoretical consideration of signal formation at micro-plasma gas analyzer based on Collisional Electron Spectroscopy (CES) and experimental results on CES sensor are presented. It is demonstrated that a diffusion path confinement for characteristic electrons provides a possibility to measure electrons energy distribution function (EEDF) and to find characteristic spectra of species at high (up to atmospheric) gas pressure. Simple micro-plasma CES sensor of two plane parallel electrode configuration with current-voltage measurement in afterglow discharge may be operated in two possible modes. The first mode presumes application of classic 2-nd derivative of current-voltage curve to select characteristic peaks in electron energy spectra of the species to be detected. In the case of a deeper collisional dissipation of characteristic peaks, a 3-rd

  13. MicroSensors Systems: detection of a dismounted threat

    NASA Astrophysics Data System (ADS)

    Shimazu, Ron N.; Berglund, Victor P.; Falkofske, Dwight M.; Krantz, Brian S.

    2004-11-01

    The MicroSensors Systems (MSS) Program is developing a layered sensor network to detect dismounted threats approaching high value assets. The MSS subsystem elements include sensitive receivers (capable of detecting<<1 Watt emissions in dense signal or degraded signal environments) and low power, miniature, disposable sensors (acoustic, magnetic, and infrared). A novel network protocol has been developed to reduce the network traffic resulting in conservation of system power and lower probability of detection and interception. The MSS program will provide unprecedented levels of real-time battlefield information, greatly enhancing combat situational awareness when integrated with the existing Command, Control, and Communications, Computers, Intelligence, Surveillance and Reconnaissance (C4ISR) infrastructure. This system will provide an important boost to realizing the information dominant, network-centric objective of Joint Vision 2020. The program has established two Centers of Excellence for Sensor Technology each of which is capable of designing and building next generation, networked microsensor systems. The Defense Microelectronics Activity has teamed with the Centers of Excellence and industry to preserve long-term Department of Defense access to key next generation manufacturing technologies.

  14. Controlling electromagnetic wave through dual heights micro-lens array of a CMOS image sensor

    NASA Astrophysics Data System (ADS)

    Lin, Kuo-Feng; Hsiao, Yu-Kun; Hsieh, Chin-Chuan; Hsin, Shui-Chuan; Hsieh, Wen-Feng

    2016-05-01

    We demonstrate control of electromagnetic (EM) wave through dual heights micro-lens (DHML) array in 1.1 μm pixel size complementary metal oxide semiconductor image sensor. The sensitivity and signal-to-noise ratio (SNR) are significantly improved (>10%) using the DHML structure. This DHML structure acts as an array of fundamental waveguides to enhance the optical throughput and to suppress the spatial crosstalk that is confirmed by evaluating the pixel performance in terms of the confinement factor of fundamental mode in this DHML structure.

  15. An Asynchronous Multi-Sensor Micro Control Unit for Wireless Body Sensor Networks (WBSNs)

    PubMed Central

    Chen, Chiung-An; Chen, Shih-Lun; Huang, Hong-Yi; Luo, Ching-Hsing

    2011-01-01

    In this work, an asynchronous multi-sensor micro control unit (MCU) core is proposed for wireless body sensor networks (WBSNs). It consists of asynchronous interfaces, a power management unit, a multi-sensor controller, a data encoder (DE), and an error correct coder (ECC). To improve the system performance and expansion abilities, the asynchronous interface is created for handshaking different clock domains between ADC and RF with MCU. To increase the use time of the WBSN system, a power management technique is developed for reducing power consumption. In addition, the multi-sensor controller is designed for detecting various biomedical signals. To prevent loss error from wireless transmission, use of an error correct coding technique is important in biomedical applications. The data encoder is added for lossless compression of various biomedical signals with a compression ratio of almost three. This design is successfully tested on a FPGA board. The VLSI architecture of this work contains 2.68-K gate counts and consumes power 496-μW at 133-MHz processing rate by using TSMC 0.13-μm CMOS process. Compared with the previous techniques, this work offers higher performance, more functions, and lower hardware cost than other micro controller designs. PMID:22164000

  16. A micro opto-mechanical displacement sensor based on micro-diffraction gratings: design and characterization.

    PubMed

    Accoto, D; Schena, E; Cidda, M; Francomano, M; Saccomandi, P; Silvestri, S

    2013-01-01

    A micro opto-mechanical displacement sensor is here presented. It is constituted by a sensing element based on two overlapped micro-diffraction gratings (MDGs). They present a platinum layer (45 nm of thick) on a glass substrate, a period of 525 µm constituted by a width of 150 µm of platinum separated (71.4% duty cycle). The working principle is based on the modulation of light intensity induced by the relative displacement between the MDGs: when a laser light perpendicularly hits the MDGs, the intensity of the transmitted light is a periodic function of the relative displacement between the two MDGs. A fiber optic is used to transport the transmitted light to a photodetector in order to avoid concerns related to the alignment between the optical components. The sensor's output is the ratio between the light intensity measured by the photodetector during the displacement of the MDGs and largest light intensity values measured in the whole range of measurement, therefore, it is lower than 1. The proposed sensor allows to discriminate displacement lower than 10 µm, using a cost effective micro-fabrication process implemented by the technique of Lift-Off. It shows a good linear behaviour in two ranges covering about one half of the MDGs period. Within the linear ranges it shows high sensitivity (about 0.5%/µm) and good accuracy (lower than 4% in the whole range of calibration); furthermore, the results show that a design with a duty cycle of 50% overcomes the marked decrease of sensitivity in a range of measurement corresponding to a grating period.

  17. Sensor Fusion of Position- and Micro-Sensors (MEMS) integrated in a Wireless Sensor Network for movement detection in landslide areas

    NASA Astrophysics Data System (ADS)

    Arnhardt, Christian; Fernández-Steeger, Tomas; Azzam, Rafig

    2010-05-01

    Monitoring systems in landslide areas are important elements of effective Early Warning structures. Data acquisition and retrieval allows the detection of movement processes and thus is essential to generate warnings in time. Apart from the precise measurement, the reliability of data is fundamental, because outliers can trigger false alarms and leads to the loss of acceptance of such systems. For the monitoring of mass movements and their risk it is important to know, if there is movement, how fast it is and how trustworthy is the information. The joint project "Sensorbased landslide early warning system" (SLEWS) deals with these questions, and tries to improve data quality and to reduce false alarm rates, due to the combination of sensor date (sensor fusion). The project concentrates on the development of a prototypic Alarm- and Early Warning system (EWS) for different types of landslides by using various low-cost sensors, integrated in a wireless sensor network (WSN). The network consists of numerous connection points (nodes) that transfer data directly or over other nodes (Multi-Hop) in real-time to a data collection point (gateway). From there all the data packages are transmitted to a spatial data infrastructure (SDI) for further processing, analyzing and visualizing with respect to end-user specifications. The ad-hoc characteristic of the network allows the autonomous crosslinking of the nodes according to existing connections and communication strength. Due to the independent finding of new or more stable connections (self healing) a breakdown of the whole system is avoided. The bidirectional data stream enables the receiving of data from the network but also allows the transfer of commands and pointed requests into the WSN. For the detection of surface deformations in landslide areas small low-cost Micro-Electro-Mechanical-Systems (MEMS) and positionsensors from the automobile industries, different industrial applications and from other measurement

  18. Development of Micro-Heaters with Optimized Temperature Compensation Design for Gas Sensors

    PubMed Central

    Hwang, Woo-Jin; Shin, Kyu-Sik; Roh, Ji-Hyoung; Lee, Dae-Sung; Choa, Sung-Hoon

    2011-01-01

    One of the key components of a chemical gas sensor is a MEMS micro-heater. Micro-heaters are used in both semiconductor gas sensors and NDIR gas sensors; however they each require different heat dissipation characteristics. For the semiconductor gas sensors, a uniform temperature is required over a wide area of the heater. On the other hand, for the NDIR gas sensor, the micro-heater needs high levels of infrared radiation in order to increase sensitivity. In this study, a novel design of a poly-Si micro-heater is proposed to improve the uniformity of heat dissipation on the heating plate. Temperature uniformity of the micro-heater is achieved by compensating for the variation in power consumption around the perimeter of the heater. With the power compensated design, the uniform heating area is increased by 2.5 times and the average temperature goes up by 40 °C. Therefore, this power compensated micro-heater design is suitable for a semiconductor gas sensor. Meanwhile, the poly-Si micro-heater without compensation shows a higher level of infrared radiation under equal power consumption conditions. This indicates that the micro-heater without compensation is more suitable for a NDIR gas sensor. Furthermore, the micro-heater shows a short response time of less than 20ms, indicating a very high efficiency of pulse driving. PMID:22163756

  19. Optimum design of 2D micro-angle sensor

    NASA Astrophysics Data System (ADS)

    Liu, Qinggang; Zhao, Heng; Lou, Xiaona; Jiang, Ningchuan; Hu, Xiaotang

    2008-12-01

    To improve dynamic measurement performance and resolution, an optimum design on two-dimensional (2D) micro-angle sensor based on optical internal-reflection method via critical-angle refractive index measurement is presented in the paper. The noise signals were filtered effectively by modulating laser-driven and demodulating in signal proceeding. The system's accuracy and response speed are improved further by using 16-bit high-precision AD converter and MSP430 CPU which present with a high-speed performance during signals processes such as fitting angle-voltage curve through specific arithmetic, full range and zero point calibration, filter, scaling transformation etc. The experiment results indicated that, dynamic signal measurement range can be up to +/-600arcsec, the measurement resolution can be better than 0.1arcsec, and the repeatability could be better than +/-0.5arcsec.

  20. Autonomous micro and nano sensors for upstream oil and gas

    NASA Astrophysics Data System (ADS)

    Chapman, David; Trybula, Walt

    2015-06-01

    This paper describes the development of autonomous electronic micro and nanoscale sensor systems for very harsh downhole oilfield conditions and provides an overview of the operational requirements necessary to survive and make direct measurements of subsurface conditions. One of several significant developmental challenges is selecting appropriate technologies that are simultaneously miniaturize-able, integrate-able, harsh environment capable, and economically viable. The Advanced Energy Consortium (AEC) is employing a platform approach to developing and testing multi-chip, millimeter and micron-scale systems in a package at elevated temperature and pressure in API brine and oil analogs, with the future goal of miniaturized systems that enable the collection of previously unattainable data. The ultimate goal is to develop subsurface nanosensor systems that can be injected into oil and gas well bores, to gather and record data, providing an unparalleled level of direct reservoir characterization. This paper provides a status update on the research efforts and developmental successes at the AEC.

  1. 3D printing of nano- and micro-structures

    NASA Astrophysics Data System (ADS)

    Ramasamy, Mouli; Varadan, Vijay K.

    2016-04-01

    Additive manufacturing or 3D printing techniques are being vigorously investigated as a replacement to the traditional and conventional methods in fabrication to bring forth cost and time effective approaches. Introduction of 3D printing has led to printing micro and nanoscale structures including tissues and organelles, bioelectric sensors and devices, artificial bones and transplants, microfluidic devices, batteries and various other biomaterials. Various microfabrication processes have been developed to fabricate micro components and assemblies at lab scale. 3D Fabrication processes that can accommodate the functional and geometrical requirements to realize complicated structures are becoming feasible through advances in additive manufacturing. This advancement could lead to simpler development mechanisms of novel components and devices exhibiting complex features. For instance, development of microstructure electrodes that can penetrate the epidermis of the skin to collect the bio potential signal may prove very effective than the electrodes that measure signal from the skin's surface. The micro and nanostructures will have to possess extraordinary material and mechanical properties for its dexterity in the applications. A substantial amount of research being pursued on stretchable and flexible devices based on PDMA, textiles, and organic electronics. Despite the numerous advantages these substrates and techniques could solely offer, 3D printing enables a multi-dimensional approach towards finer and complex applications. This review emphasizes the use of 3D printing to fabricate micro and nanostructures for that can be applied for human healthcare.

  2. Further Structural Intelligence for Sensors Cluster Technology in Manufacturing

    PubMed Central

    Mekid, Samir

    2006-01-01

    With the ever increasing complex sensing and actuating tasks in manufacturing plants, intelligent sensors cluster in hybrid networks becomes a rapidly expanding area. They play a dominant role in many fields from macro and micro scale. Global object control and the ability to self organize into fault-tolerant and scalable systems are expected for high level applications. In this paper, new structural concepts of intelligent sensors and networks with new intelligent agents are presented. Embedding new functionalities to dynamically manage cooperative agents for autonomous machines are interesting key enabling technologies most required in manufacturing for zero defects production.

  3. Traceable Micro-Force Sensor for Instrumented Indentation Calibration

    SciTech Connect

    Smith, D T; Shaw, G A; Seugling, R M; Xiang, D; Pratt, J R

    2007-04-02

    Instrumented indentation testing (IIT), commonly referred to as nanoindentation when small forces are used, is a popular technique for determining the mechanical properties of small volumes of material. Sample preparation is relatively easy, usually requiring only that a smooth surface of the material to be tested be accessible to a contact probe, and instruments that combine sophisticated automation with straightforward user interfaces are available commercially from several manufacturers. In addition, documentary standards are now becoming available from both the International Standards Organization (ISO 14577) and ASTM International (E28 WK382) that define test methods and standard practices for IIT, and will allow the technique to be used to produce material property data that can be used in product specifications. These standards also define the required level of accuracy of the force data produced by IIT instruments, as well as methods to verify that accuracy. For forces below 10 mN, these requirements can be difficult to meet, particularly for instrument owners who need to verify the performance of their instrument as it is installed at their site. In this paper, we describe the development, performance and application of an SI-traceable force sensor system for potential use in the field calibration of commercial IIT instruments. The force sensor itself, based on an elastically deforming capacitance gauge, is small enough to mount in a commercial instrument as if it were a test specimen, and is used in conjunction with an ultra-high accuracy capacitance bridge. The sensor system is calibrated with NIST-traceable masses over the range 5.0 {micro}N through 5.0 mN. We will present data on its accuracy and precision, as well its potential application to the verification of force in commercial instrumented indentation instruments.

  4. Design and characterization of a silicon piezoresistive three-axial force sensor for micro-flapping wing MAV applications

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Truong, Van T.; Lua, Kim B.; Kumar, A. S.; Lim, Tee Tai; Yeo, Khoon Seng; Zhou, Guangya

    2015-03-01

    This paper describes the design and electro-mechanical characterizations of a three-axial micro piezoresistive force sensor fabricated by microelectromechanical systems (MEMS) technologies. This is the first three-axial MEMS micro force sensor applied to the study of Micro Aerial Vehicle (MAV) aerodynamics. A standard dry etching fabrication process using Silicon On Insulator (SOI) wafer is employed to fabricate the multi-axis sensors. Conventional cross-beam structure is employed. There are eight piezoresistors on the beams, and each of the silicon strain gauge size is 15 μm in width, and between 400 and 500 μm in length. The Finite Element Method (FEM) analysis for confirming the piezoresistors attachment locations is performed. The miniaturized force sensor (11×11 mm2) is attached at the wing base of a micro flapping wing system (MAV, 70×30 mm2 ) by a short pillar. The sensor is designed to detect the dynamic drag force and lift force generated by a single wing under a moderate flapping frequency (5~10Hz) simultaneously. The characterizations are experimentally investigated. The sensor should be stiff enough to withstand the high inertial force (200 millinewton) and also has high resolution to detect the minimal force correctly. Measurements show that the resolution is on the order of a millinewton. High linearity and low hysteresis under normal forces and tangential forces are demonstrated by applying forces from 0 to 0.1 N. The micro flapping wing mechanism and the assembly of wing and sensor are also discussed in this paper.

  5. All-fiber micro-machined Fabry-Perot strain sensor

    NASA Astrophysics Data System (ADS)

    Pevec, Simon; Đonlagić, Denis

    2012-04-01

    This paper presents the design, fabrication process, and experimental evaluation of a high-sensitivity, all-silica, all-fiber, micro machined Fabry-Perot strain-sensor. This sensor has a short Fabry-Perot cavity and thus allows for the application of low-resolution spectral interrogation systems; in our case the commercial white light signal interrogator was used. The fabrication process includes the design and production of special sensor-forming optical-fiber. This fiber includes a central titanium-doped region, a phosphorus doped-ring surrounding a titanium doped region, and pure silica cladding in order to produce the proposed sensor, two sections of sensor forming fiber are cleaved and etched in a HF/IPA solution. The phosphorus-doped region etches at a considerably higher rate than the other fiber-sections, and thus creates a deep gutter on the cleaved fibers frontal surface. The titanium-doped region etches at a rate that is, to some extent, higher than the etching-rate of pure silica, and thus creates a slightly retracted surface relative to the pure silica fiber-cladding. The etched fibers are then re-spliced to create an all-silica strain sensor in "double configuration", which has a section of etched sensor-forming fiber on both sides. Thus this sensor has a long active length, whilst the length of the Fabry-Perot cavity can be adjusted by a titanium-doping level. The central titanium-doped region also creates a waveguide structure that is used to deliver light to the cavity through one of the fibers. The proposed fabrication process is cost-effective and suitable for high-volume production. The greatest achievement of the depicted in-line strain sensor is the extension of its active sensor length, which is more than 50 times greater than the sensor-cavity's length, and is thus approximately 50 times more sensitive to strain. This sensor also exhibits low-intrinsic temperature sensitivity.

  6. High-Resolution Macromolecular Structure Determination by MicroED, a cryo-EM Method.

    PubMed

    Rodriguez, J A; Gonen, T

    2016-01-01

    Microelectron diffraction (MicroED) is a new cryo-electron microscopy (cryo-EM) method capable of determining macromolecular structures at atomic resolution from vanishingly small 3D crystals. MicroED promises to solve atomic resolution structures from even the tiniest of crystals, less than a few hundred nanometers thick. MicroED complements frontier advances in crystallography and represents part of the rebirth of cryo-EM that is making macromolecular structure determination more accessible for all. Here we review the concept and practice of MicroED, for both the electron microscopist and crystallographer. Where other reviews have addressed specific details of the technique (Hattne et al., 2015; Shi et al., 2016; Shi, Nannenga, Iadanza, & Gonen, 2013), we aim to provide context and highlight important features that should be considered when performing a MicroED experiment.

  7. High-Resolution Macromolecular Structure Determination by MicroED, a cryo-EM Method.

    PubMed

    Rodriguez, J A; Gonen, T

    2016-01-01

    Microelectron diffraction (MicroED) is a new cryo-electron microscopy (cryo-EM) method capable of determining macromolecular structures at atomic resolution from vanishingly small 3D crystals. MicroED promises to solve atomic resolution structures from even the tiniest of crystals, less than a few hundred nanometers thick. MicroED complements frontier advances in crystallography and represents part of the rebirth of cryo-EM that is making macromolecular structure determination more accessible for all. Here we review the concept and practice of MicroED, for both the electron microscopist and crystallographer. Where other reviews have addressed specific details of the technique (Hattne et al., 2015; Shi et al., 2016; Shi, Nannenga, Iadanza, & Gonen, 2013), we aim to provide context and highlight important features that should be considered when performing a MicroED experiment. PMID:27572734

  8. Global Environmental Micro Sensors Test Operations in the Natural Environment

    NASA Technical Reports Server (NTRS)

    Adams, Mark L.; Buza, Matthew; Manobianco, John; Merceret, Francis J.

    2007-01-01

    ENSCO, Inc. is developing an innovative atmospheric observing system known as Global Environmental Micro Sensors (GEMS). The GEMS concept features an integrated system of miniaturized in situ, airborne probes measuring temperature, relative humidity, pressure, and vector wind velocity. In order for the probes to remain airborne for long periods of time, their design is based on a helium-filled super-pressure balloon. The GEMS probes are neutrally buoyant and carried passively by the wind at predetermined levels. Each probe contains onboard satellite communication, power generation, processing, and geolocation capabilities. ENSCO has partnered with the National Aeronautics and Space Administration's Kennedy Space Center (KSC) for a project called GEMS Test Operations in the Natural Environment (GEMSTONE) that will culminate with limited prototype flights of the system in spring 2007. By leveraging current advances in micro and nanotechnology, the probe mass, size, cost, and complexity can be reduced substantially so that large numbers of probes could be deployed routinely to support ground, launch, and landing operations at KSC and other locations. A full-scale system will improve the data density for the local initialization of high-resolution numerical weather prediction systems by at least an order of magnitude and provide a significantly expanded in situ data base to evaluate launch commit criteria and flight rules. When applied to launch or landing sites, this capability will reduce both weather hazards and weather-related scrubs, thus enhancing both safety and cost-avoidance for vehicles processed by the Shuttle, Launch Services Program, and Constellation Directorates. The GEMSTONE project will conclude with a field experiment in which 10 to 15 probes are released over KSC in east central Florida. The probes will be neutrally buoyant at different altitudes from 500 to 3000 meters and will report their position, speed, heading, temperature, humidity, and

  9. Structure and yarn sensor for fabric

    DOEpatents

    Mee, David K.; Allgood, Glenn O.; Mooney, Larry R.; Duncan, Michael G.; Turner, John C.; Treece, Dale A.

    1998-01-01

    A structure and yarn sensor for fabric directly determines pick density in a fabric thereby allowing fabric length and velocity to be calculated from a count of the picks made by the sensor over known time intervals. The structure and yarn sensor is also capable of detecting full length woven defects and fabric. As a result, an inexpensive on-line pick (or course) density measurement can be performed which allows a loom or knitting machine to be adjusted by either manual or automatic means to maintain closer fiber density tolerances. Such a sensor apparatus dramatically reduces fabric production costs and significantly improves fabric consistency and quality for woven or knitted fabric.

  10. Structural Alignment Sensor Feasibility Demonstration

    NASA Technical Reports Server (NTRS)

    Anderson, R. H.; Huang, C. C.; Hodor, J. R.

    1978-01-01

    A structural alignment sensor (SAS) was developed for use with large deployable antenna systems for contour measurement and/or active control. The SAS is a laser ranging system using frequency modulation and accurate phase measurement to determine distance. Work was done with a CO2 and HeNe laser. The capability of the SAS to measure antenna rib contours was studied over ranges of 50 meters to a resolution of 100 microns. Initial resolution data was taken with the CO2 system. This data shows that it will indeed meet the SAS requirements. The development of the HeNe system was initiated because it offers substantial improvement in size, weight, and power over the CO2 system. The final demonstration was made with the HeNe system and it too showed that the SAS requirements could be met with this alternate approach. The projection of these results to a conceptual design for a flight system and its application are described.

  11. A highly sensitive Pb(Zr,Ti)O3 thin film ultrasonic micro-sensor with a grooved diaphragm.

    PubMed

    Matsushima, Tomoaki; Xiong, Sibei; Kawada, Hiroshi; Yamanaka, Hiroshi; Muralt, Paul

    2007-12-01

    A highly sensitive piezoelectric ultrasonic micro-sensor with a grooved multilayer membrane was developed by a Si-based MEMS technique. The groove was located at one-quarter of the distance away from the edge of the membrane and opened into piezoelectric layer. The piezoelectric layer Pb(Zr,Ti)O(3) (PZT) was 2.2 microm thick and was prepared by a sol-gel method. The prepared PZT film was pure perovskite and showed a highly (100) textured structure. The sensitivity of the fabricated piezoelectric ultrasonic sensor without the groove structure was 100 microV/Pa. In comparison, the sensitivity of the ultrasonic sensor with the groove structure was about 500 microV/Pa, which is 5 times that without the groove structure. The diaphragm having grooves showed a corrugate-like structure that was formed by residual stress. The high sensitivity of the membrane with the grooved diaphragm is considered to relate to the corrugate-like structure.

  12. Design and analysis of photonic crystal micro-cavity based optical sensor platform

    NASA Astrophysics Data System (ADS)

    Goyal, Amit Kumar; Dutta, Hemant Sankar; Pal, Suchandan

    2016-04-01

    In this paper, the design of a two-dimensional photonic crystal micro-cavity based integrated-optic sensor platform is proposed. The behaviour of designed cavity is analyzed using two-dimensional Finite Difference Time Domain (FDTD) method. The structure is designed by deliberately inserting some defects in a photonic crystal waveguide structure. Proposed structure shows a quality factor (Q) of about 1e5 and the average sensitivity of 500nm/RIU in the wavelength range of 1450 - 1580 nm. Sensing technique is based on the detection of shift in upper-edge cut-off wavelength for a reference signal strength of -10 dB in accordance with the change in refractive index of analyte.

  13. Selected examples of intelligent (micro) sensor systems: state-of-the-art and tendencies

    NASA Astrophysics Data System (ADS)

    Hauptmann, Peter R.

    2006-03-01

    The capability of intelligent sensors to have more intelligence built into them continues to drive their application in areas including automotive, aerospace and defense, industrial, intelligent house and wear, medical and homeland security. In principle it is difficult to overestimate the importance of intelligent (micro) sensors or sensor systems within advanced societies but one characteristic feature is the global market for sensors, which is now about 20 billion annually. Therefore sensors or sensor systems play a dominant role in many fields from the macro sensor in manufacturing industry down to the miniaturized sensor for medical applications. The diversity of sensors precludes a complete description of the state-of-the-art; selected examples will illustrate the current situation. MEMS (microelectromechanical systems) devices are of special interest in the context of micro sensor systems. In past the main requirements of a sensor were in terms of metrological performance. The electrical (or optical) signal produced by the sensor needed to match the measure relatively accurately. Such basic functionality is no longer sufficient. Data processing near the sensor, the extraction of more information than just the direct sensor information by signal analysis, system aspects and multi-sensor information are the new demands. A shifting can be observed away from aiming to design perfect single-function transducers and towards the utilization of system-based sensors as system components. In the ideal case such systems contain sensors, actuators and electronics. They can be realized in monolithic, hybrid or discrete form—which kind is used depends on the application. In this article the state-of-the-art of intelligent sensors or sensor systems is reviewed using selected examples. Future trends are deduced.

  14. Micro-LiDAR velocity, temperature, density, concentration sensor

    NASA Technical Reports Server (NTRS)

    Danehy, Paul M. (Inventor); Dorrington, Adrian A. (Inventor)

    2010-01-01

    A light scatter sensor includes a sensor body in which are positioned a plurality of optical fibers. The sensor body includes a surface, in one end of each of the optical fibers terminates at the surface of the sensor body. One of the optical fibers is an illumination fiber for emitting light. A plurality of second optical fibers are collection fibers for collecting scattered light signals. A light sensor processor is connected to the collection fibers to detect the scattered light signals.

  15. Pulse-driven micro gas sensor fitted with clustered Pd/SnO2 nanoparticles.

    PubMed

    Suematsu, Koichi; Shin, Yuka; Ma, Nan; Oyama, Tokiharu; Sasaki, Miyuki; Yuasa, Masayoshi; Kida, Tetsuya; Shimanoe, Kengo

    2015-08-18

    Real-time monitoring of specific gas concentrations with a compact and portable gas sensing device is required to sense potential health risk and danger from toxic gases. For such purposes, we developed an ultrasmall gas sensor device, where a micro sensing film was deposited on a micro heater integrated with electrodes fabricated by the microelectromechanical system (MEMS) technology. The developed device was operated in a pulse-heating mode to significantly reduce the heater power consumption and make the device battery-driven and portable. Using clustered Pd/SnO2 nanoparticles, we succeeded in introducing mesopores ranging from 10 to 30 nm in the micro gas sensing film (area: ϕ 150 μm) to detect large volatile organic compounds (VOCs). The micro sensor showed quick, stable, and high sensor responses to toluene at ppm (parts per million) concentrations at 300 °C even by operating the micro heater in a pulse-heating mode where switch-on and -off cycles were repeated at one-second intervals. The high performance of the micro sensor should result from the creation of efficient diffusion paths decorated with Pd sensitizers by using the clustered Pd/SnO2 nanoparticles. Hence we demonstrate that our pulse-driven micro sensor using nanostructured oxide materials holds promise as a battery-operable, portable gas sensing device. PMID:26196499

  16. Inline chemical process analysis in micro-plants based on thermoelectric flow and impedimetric sensors

    NASA Astrophysics Data System (ADS)

    Jacobs, T.; Kutzner, C.; Kropp, M.; Brokmann, G.; Lang, W.; Steinke, A.; Kienle, A.; Hauptmann, P.

    2010-10-01

    In micro-plants, as used in chemical micro-process engineering, an integrated inline analytics is regarded as an important factor for the development and optimization of chemical processes. Up to now, there is a lack of sensitive, robust and low-priced micro-sensors for monitoring mixing and chemical conversion in micro-fluidic channels. In this paper a novel sensor system combining an impedimetric sensor and a novel pressure stable thermoelectric flow sensor for monitoring chemical reactions in micro-plants is presented. The CMOS-technology-based impedimetric sensor mainly consists of two capacitively coupled interdigital electrodes on a silicon chip. The thermoelectric flow sensor consists of a heater in between two thermopiles on a perforated membrane. The pulsed and constant current feeds of the heater were analyzed. Both sensors enable the analysis of chemical conversion by means of changes in the thermal and electrical properties of the liquid. The homogeneously catalyzed synthesis of n-butyl acetate as a chemical model system was studied. Experimental results revealed that in an overpressure regime, relative changes of less than 1% in terms of thermal and electrical properties can be detected. Furthermore, the transition from one to two liquid phases accompanied by the change in slug flow conditions could be reproducibly detected.

  17. On-chip micro-power: three-dimensional structures for micro-batteries and micro-supercapacitors

    NASA Astrophysics Data System (ADS)

    Beidaghi, Majid; Wang, Chunlei

    2010-04-01

    With the miniaturization of portable electronic devices, there is a demand for micro-power source which can be integrated on the semiconductor chips. Various micro-batteries have been developed in recent years to generate or store the energy that is needed by microsystems. Micro-supercapacitors are also developed recently to couple with microbatteries and energy harvesting microsystems and provide the peak power. Increasing the capacity per footprint area of micro-batteries and micro-supercapacitors is a great challenge. One promising route is the manufacturing of three dimensional (3D) structures for these micro-devices. In this paper, the recent advances in fabrication of 3D structure for micro-batteries and micro-supercapacitors are briefly reviewed.

  18. Optical Fiber Sensors for Advanced Civil Structures

    NASA Astrophysics Data System (ADS)

    de Vries, Marten Johannes Cornelius

    1995-01-01

    The objective of this dissertation is to develop, analyze, and implement optical fiber-based sensors for the nondestructive quantitative evaluation of advanced civil structures. Based on a comparative evaluation of optical fiber sensors that may be used to obtain quantitative information related to physical perturbations in the civil structure, the extrinsic Fabry-Perot interferometric (EFPI) optical fiber sensor is selected as the most attractive sensor. The operation of the EFPI sensor is explained using the Kirchhoff diffraction approach. As is shown in this dissertation, this approach better predicts the signal-to-noise ratio as a function of gap length than methods employed previously. The performance of the optical fiber sensor is demonstrated in three different implementations. In the first implementation, performed with researchers in the Civil Engineering Department at the University of Southern California in Los Angeles, optical fiber sensors were used to obtain quantitative strain information from reinforced concrete interior and exterior column-to-beam connections. The second implementation, performed in cooperation with researchers at the United States Bureau of Mines in Spokane, Washington, used optical fiber sensors to monitor the performance of roof bolts used in mines. The last implementation, performed in cooperation with researchers at the Turner-Fairbanks Federal Highway Administration Research Center in McLean, Virginia, used optical fiber sensors, attached to composite prestressing strands used for reinforcing concrete, to obtain absolute strain information. Multiplexing techniques including time, frequency and wavelength division multiplexing are briefly discussed, whereas the principles of operation of spread spectrum and optical time domain reflectometery (OTDR) are discussed in greater detail. Results demonstrating that spread spectrum and OTDR techniques can be used to multiplex optical fiber sensors are presented. Finally, practical

  19. Optical coherent sensor for monitoring and measurement of engineering structures

    NASA Astrophysics Data System (ADS)

    Łukaszewski, Dariusz; Sałbut, Leszek; Dziuban, Jan A.

    2010-05-01

    Among many coherent optical methods one should distinguished Grating Interferometry (GI) which allows accurate in-plane displacement measurements and Digital Speckle Pattern Interferometry (DSPI) used for in-plane and out-of-plane measurements. Development of sensors based on both methods mentioned above as complementary ones will provide user universal group of sensors from which depending on measurement requirements such as measuring range, object surface profile and measurement conditions the most appropriate can be chosen. In-plane displacement measurements are of interested of different branches of industry - from micro (i.e.: characterization of MEMS or MOEMS) to civil engineering (i.e.: Structural Health Monitoring systems). In the paper the new optical coherent sensor for in-plane displacement and strain measurements is presented. The sensor combines GI and DSPI methods in one device which can be used for testing of objects with different types of surfaces. GI requires the specimen grating attached at the surface but provides very good measurement accuracy however DSPI can be applied for testing of objects with rough surfaces but due to higher noise gives lower accuracy. The sensor can work in three modes: as GI only, DSPI only and both GI and DSPI simultaneously. The third mode can by useful when the specimen grating is attached on the part of object under test only. In the paper the theoretical background of the sensor is presented. For confirmation of GI/DSPI sensor possibilities the specially designed demonstrator is described and the exemplary results obtained during its laboratory tests are shown. Successful application of proposed sensor is possible due to its miniaturization, simplicity of operation by user (compact structure and automation of measurement procedure) and low cost. The last mentioned condition will be possible due to low cost replication techniques with usage of silicon technology.

  20. Model-based Processing of Micro-cantilever Sensor Arrays

    SciTech Connect

    Tringe, J W; Clague, D S; Candy, J V; Lee, C L; Rudd, R E; Burnham, A K

    2004-11-17

    We develop a model-based processor (MBP) for a micro-cantilever array sensor to detect target species in solution. After discussing the generalized framework for this problem, we develop the specific model used in this study. We perform a proof-of-concept experiment, fit the model parameters to the measured data and use them to develop a Gauss-Markov simulation. We then investigate two cases of interest: (1) averaged deflection data, and (2) multi-channel data. In both cases the evaluation proceeds by first performing a model-based parameter estimation to extract the model parameters, next performing a Gauss-Markov simulation, designing the optimal MBP and finally applying it to measured experimental data. The simulation is used to evaluate the performance of the MBP in the multi-channel case and compare it to a ''smoother'' (''averager'') typically used in this application. It was shown that the MBP not only provides a significant gain ({approx} 80dB) in signal-to-noise ratio (SNR), but also consistently outperforms the smoother by 40-60 dB. Finally, we apply the processor to the smoothed experimental data and demonstrate its capability for chemical detection. The MBP performs quite well, though it includes a correctable systematic bias error. The project's primary accomplishment was the successful application of model-based processing to signals from micro-cantilever arrays: 40-60 dB improvement vs. the smoother algorithm was demonstrated. This result was achieved through the development of appropriate mathematical descriptions for the chemical and mechanical phenomena, and incorporation of these descriptions directly into the model-based signal processor. A significant challenge was the development of the framework which would maximize the usefulness of the signal processing algorithms while ensuring the accuracy of the mathematical description of the chemical-mechanical signal. Experimentally, the difficulty was to identify and characterize the non

  1. Phase coded, micro-power impulse radar motion sensor

    DOEpatents

    McEwan, T.E.

    1996-05-21

    A motion sensing, micro-power impulse radar MIR impresses on the transmitted signal, or the received pulse timing signal, one or more frequencies lower than the pulse repetition frequency, that become intermediate frequencies in a ``IF homodyne`` receiver. Thus, many advantages of classical RF receivers can be thereby be realized with ultra-wide band radar. The sensor includes a transmitter which transmits a sequence of electromagnetic pulses in response to a transmit timing signal at a nominal pulse repetition frequency. A receiver samples echoes of the sequence of electromagnetic pulses from objects within the field with controlled timing, in response to a receive timing signal, and generates a sample signal in response to the samples. A timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The relative timing of the transmit timing signal and the receive timing signal is modulated between a first relative delay and a second relative delay at an intermediate frequency, causing the receiver to sample the echoes such that the time between transmissions of pulses in the sequence and samples by the receiver is modulated at the intermediate frequency. Modulation may be executed by modulating the pulse repetition frequency which drives the transmitter, by modulating the delay circuitry which controls the relative timing of the sample strobe, or by modulating amplitude of the transmitted pulses. The electromagnetic pulses will have a nominal center frequency related to pulse width, and the first relative delay and the second relative delay between which the timing signals are modulated, differ by less than the nominal pulse width, and preferably by about one-quarter wavelength at the nominal center frequency of the transmitted pulses. 5 figs.

  2. Phase coded, micro-power impulse radar motion sensor

    DOEpatents

    McEwan, Thomas E.

    1996-01-01

    A motion sensing, micro-power impulse radar MIR impresses on the transmitted signal, or the received pulse timing signal, one or more frequencies lower than the pulse repetition frequency, that become intermediate frequencies in a "IF homodyne" receiver. Thus, many advantages of classical RF receivers can be thereby be realized with ultra-wide band radar. The sensor includes a transmitter which transmits a sequence of electromagnetic pulses in response to a transmit timing signal at a nominal pulse repetition frequency. A receiver samples echoes of the sequence of electromagnetic pulses from objects within the field with controlled timing, in response to a receive timing signal, and generates a sample signal in response to the samples. A timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The relative timing of the transmit timing signal and the receive timing signal is modulated between a first relative delay and a second relative delay at an intermediate frequency, causing the receiver to sample the echoes such that the time between transmissions of pulses in the sequence and samples by the receiver is modulated at the intermediate frequency. Modulation may be executed by modulating the pulse repetition frequency which drives the transmitter, by modulating the delay circuitry which controls the relative timing of the sample strobe, or by modulating amplitude of the transmitted pulses. The electromagnetic pulses will have a nominal center frequency related to pulse width, and the first relative delay and the second relative delay between which the timing signals are modulated, differ by less than the nominal pulse width, and preferably by about one-quarter wavelength at the nominal center frequency of the transmitted pulses.

  3. Light-Weight Sensor Package for Precision 3d Measurement with Micro Uavs E.G. Power-Line Monitoring

    NASA Astrophysics Data System (ADS)

    Kuhnert, K.-D.; Kuhnert, L.

    2013-08-01

    The paper describes a new sensor package for micro or mini UAVs and one application that has been successfully implemented with this sensor package. It is intended for 3D measurement of landscape or large outdoor structures for mapping or monitoring purposes. The package can be composed modularly into several configurations. It may contain a laser-scanner, camera, IMU, GPS and other sensors as required by the application. Also different products of the same sensor type have been integrated. Always it contains its own computing infrastructure and may be used for intelligent navigation, too. It can be operated in cooperation with different drones but also completely independent of the type of drone it is attached to. To show the usability of the system, an application in monitoring high-voltage power lines that has been successfully realised with the package is described in detail.

  4. Micro/nano-mechanical sensors and actuators based on SOI-MEMS technology

    NASA Astrophysics Data System (ADS)

    Viet Dao, Dzung; Nakamura, Koichi; Thanh Bui, Tung; Sugiyama, Susumu

    2010-03-01

    MEMS (micro-electro-mechanical systems) technology has undergone almost 40 years of development, with significant technology advancement and successful commercialization of single-functional MEMS devices, such as pressure sensors, accelerometers, gyroscopes, microphones, micro-mirrors, etc. In this context of MEMS technology, this paper introduces our studies and developments of novel micro/nano-mechanical sensors and actuators based on silicon- on-insulator (SOI)-MEMS technology, as well as fundamental research on piezoresistive effects in single-crystal silicon nanowires (SiNWs). In the first area, novel mechanical sensors, such as 6-DOF micro-force moment sensors, multi-axis inertial sensors and micro-electrostatic actuators developed with SOI-MEMS technology will be presented. In the second area, we have combined atomic-level simulation and experimental evaluation methods to explain the giant piezoresistive effect in single crystalline SiNWs along different crystallographic orientations. This discovery is significant for developing more highly sensitive and miniaturized mechanical sensors in the near future.

  5. Sensitivity enhancement in optical micro-tube resonator sensors via mode coupling

    NASA Astrophysics Data System (ADS)

    Ling, Tao; Guo, L. Jay

    2013-07-01

    A liquid filled, silica micro-tube with a low refractive index material inner-coating has been proposed and theoretically studied as a coupled micro-resonator sensor to greatly enhance biochemical sensor sensitivity. Its unique coupling phenomenon has been analyzed and utilized to boost the device's refractive index sensitivity to 967 nm/Refractive Index Unit (RIU). Through optimization of the coupling strength between the two micro-resonators, further improvement in refractive index sensitivity up to 1100 nm/RIU has been predicted. This mode coupling strategy allows us to design robust, thick-walled micro-tube sensors with ultra-high sensitivity which is useful in practical biochemical sensing applications.

  6. Piezoelectric Sensor Evaluation for Structural Health Monitoring of Cryogenic Structures

    NASA Technical Reports Server (NTRS)

    Lassiter, John; Engberg, Robert

    2005-01-01

    This viewgraph presentation provides an overview of Structural Health Monitoring (SHM), and profiles piezoelectric sensors useful for SHM of cryogenic structures. The presentation also profiles impedance tests and other SHM tests conducted at Marshall Space Flight Center (MSFC).

  7. Micro optical fiber light source and sensor and method of fabrication thereof

    DOEpatents

    Kopelman, Raoul; Tan, Weihong; Shi, Zhong-You

    1997-01-01

    This invention relates generally to the development of and a method of fabricating a fiber optic micro-light source and sensor (50). An optical fiber micro-light source (50) is presented whose aperture is extremely small yet able to act as an intense light source. Light sources of this type have wide ranging applications, including use as micro-sensors (22) in NSOM. Micro-sensor light sources have excellent detection limits as well as photo stability, reversibility, and millisecond response times. Furthermore, a method for manufacturing a micro optical fiber light source is provided. It involves the photo-chemical attachment of an optically active material onto the end surface of an optical fiber cable which has been pulled to form an end with an extremely narrow aperture. More specifically, photopolymerization has been applied as a means to photo-chemically attach an optically active material (60). This process allows significant control of the size of the micro light source (50). Furthermore, photo-chemically attaching an optically active material (60) enables the implementation of the micro-light source in a variety of sensor applications.

  8. Micro optical fiber light source and sensor and method of fabrication thereof

    DOEpatents

    Kopelman, R.; Tan, W.; Shi, Z.Y.

    1997-05-06

    This invention relates generally to the development of and a method of fabricating a fiber optic micro-light source and sensor. An optical fiber micro-light source is presented whose aperture is extremely small yet able to act as an intense light source. Light sources of this type have wide ranging applications, including use as micro-sensors in NSOM. Micro-sensor light sources have excellent detection limits as well as photo stability, reversibility, and millisecond response times. Furthermore, a method for manufacturing a micro optical fiber light source is provided. It involves the photo-chemical attachment of an optically active material onto the end surface of an optical fiber cable which has been pulled to form an end with an extremely narrow aperture. More specifically, photopolymerization has been applied as a means to photo-chemically attach an optically active material. This process allows significant control of the size of the micro light source. Furthermore, photo-chemically attaching an optically active material enables the implementation of the micro-light source in a variety of sensor applications. 10 figs.

  9. Design and coupled-effect simulations of CMOS micro gas sensors built on SOI thin membranes

    NASA Astrophysics Data System (ADS)

    Lu, Chih-Cheng; Udrea, Florin; Gardner, Julian W.; Setiadi, D.; Dogaru, T.; Tsai, T. H.; Covington, James A.

    2001-04-01

    This paper describes coupled-effect simulations of smart micro gas-sensors based on standard BiCMOS technology. The smart sensor features very low power consumption, high sensitivity and potential low fabrication cost achieved through full CMOS integration. For the first time the micro heaters are made of active CMOS elements (i.e. MOSFET transistors) and embedded in a thin SOI membrane consisting of Si and SiO2 thin layers. Micro gas-sensors such as chemoresistive, microcalorimeteric and Pd/polymer gate FET sensors can be made using this technology. Full numerical analyses including 3D electro- thermo-mechanical simulations, in particular stress and deflection studies on the SOI membranes are presented. The transducer circuit design and the post-CMOS fabrication process, which includes single sided back-etching, are also reported.

  10. The Non-Destructive Test of Steel Corrosion in Reinforced Concrete Bridges Using a Micro-Magnetic Sensor.

    PubMed

    Zhang, Hong; Liao, Leng; Zhao, Ruiqiang; Zhou, Jianting; Yang, Mao; Xia, Runchuan

    2016-09-06

    This paper presents a non-destructive test method for steel corrosion in reinforced concrete bridges by using a 3-dimensional digital micro-magnetic sensor to detect and analyze the self-magnetic field leakage from corroded reinforced concrete. The setup of the magnetic scanning device and the measurement mode of the micro-magnetic sensor are introduced. The numerical analysis model is also built based on the linear magnetic charge theory. Compared to the self-magnetic field leakage data obtained from magnetic sensor-based measurement and numerical calculation, it is shown that the curves of tangential magnetic field at different lift-off height all intersect near the edge of the steel corrosion zone. The result indicates that the intersection of magnetic field curves can be used to detect and evaluate the range of the inner steel corrosion in engineering structures. The findings of this work propose a new and effective non-destructive test method for steel corrosion, and therefore enlarge the application of the micro-magnetic sensor.

  11. The Non-Destructive Test of Steel Corrosion in Reinforced Concrete Bridges Using a Micro-Magnetic Sensor

    PubMed Central

    Zhang, Hong; Liao, Leng; Zhao, Ruiqiang; Zhou, Jianting; Yang, Mao; Xia, Runchuan

    2016-01-01

    This paper presents a non-destructive test method for steel corrosion in reinforced concrete bridges by using a 3-dimensional digital micro-magnetic sensor to detect and analyze the self-magnetic field leakage from corroded reinforced concrete. The setup of the magnetic scanning device and the measurement mode of the micro-magnetic sensor are introduced. The numerical analysis model is also built based on the linear magnetic charge theory. Compared to the self-magnetic field leakage data obtained from magnetic sensor-based measurement and numerical calculation, it is shown that the curves of tangential magnetic field at different lift-off height all intersect near the edge of the steel corrosion zone. The result indicates that the intersection of magnetic field curves can be used to detect and evaluate the range of the inner steel corrosion in engineering structures. The findings of this work propose a new and effective non-destructive test method for steel corrosion, and therefore enlarge the application of the micro-magnetic sensor. PMID:27608029

  12. The Non-Destructive Test of Steel Corrosion in Reinforced Concrete Bridges Using a Micro-Magnetic Sensor.

    PubMed

    Zhang, Hong; Liao, Leng; Zhao, Ruiqiang; Zhou, Jianting; Yang, Mao; Xia, Runchuan

    2016-01-01

    This paper presents a non-destructive test method for steel corrosion in reinforced concrete bridges by using a 3-dimensional digital micro-magnetic sensor to detect and analyze the self-magnetic field leakage from corroded reinforced concrete. The setup of the magnetic scanning device and the measurement mode of the micro-magnetic sensor are introduced. The numerical analysis model is also built based on the linear magnetic charge theory. Compared to the self-magnetic field leakage data obtained from magnetic sensor-based measurement and numerical calculation, it is shown that the curves of tangential magnetic field at different lift-off height all intersect near the edge of the steel corrosion zone. The result indicates that the intersection of magnetic field curves can be used to detect and evaluate the range of the inner steel corrosion in engineering structures. The findings of this work propose a new and effective non-destructive test method for steel corrosion, and therefore enlarge the application of the micro-magnetic sensor. PMID:27608029

  13. Structural health monitoring with fiber optic sensors

    NASA Astrophysics Data System (ADS)

    Güemes, Alfredo; Fernandez-Lopez, Antonio

    2014-05-01

    SHM is defined as the process of acquiring and analyzing data from on-board sensors to evaluate the health of a structure. Most common damages on aircrafts are local cracks and delaminations, that do not change strongly the overall strain field, but that will act as the failure initiation point. Fiber optic sensors act primarily as strain sensors, so unless damage happens very close to the sensor location, it may go undetected. Currently, three main approaches for detecting damage from strain measurements are being investigated: 1) High resolution fibre optic distributed sensing (OFDR Rayleigh scattering). 2) Strain mapping with a dense network of sensors. Statistical analysis tools, like PCA, have been successfully used. 3) Hybrid FBG/PZT systems. FBGs must detect the ultrasonic elastic waves.

  14. Thermal chip fabrication with arrays of sensors and heaters for micro-scale impingement cooling heat transfer analysis and measurements.

    PubMed

    Shen, C H; Gau, C

    2004-07-30

    The design and fabrication for a thermal chip with an array of temperature sensors and heaters for study of micro-jet impingement cooling heat transfer process are presented. This thermal chip can minimize the heat loss from the system to the ambient and provide a uniform heat flux along the wall, thus local heat transfer processes along the wall can be measured and obtained. The fabrication procedure presented can reach a chip yield of 100%, and every one of the sensors and heaters on the chip is in good condition. In addition, micro-jet impingement cooling experiments are performed to obtain the micro-scale local heat transfer Nusselt number along the wall. Flow visualization for the micro-impinging jet is also made. The experimental results indicate that both the micro-scale impinging jet flow structure and the heat transfer process along the wall is significantly different from the case of large-scale jet impingement cooling process. PMID:15142582

  15. Structure and yarn sensor for fabric

    DOEpatents

    Mee, D.K.; Allgood, G.O.; Mooney, L.R.; Duncan, M.G.; Turner, J.C.; Treece, D.A.

    1998-10-20

    A structure and yarn sensor for fabric directly determines pick density in a fabric thereby allowing fabric length and velocity to be calculated from a count of the picks made by the sensor over known time intervals. The structure and yarn sensor is also capable of detecting full length woven defects and fabric. As a result, an inexpensive on-line pick (or course) density measurement can be performed which allows a loom or knitting machine to be adjusted by either manual or automatic means to maintain closer fiber density tolerances. Such a sensor apparatus dramatically reduces fabric production costs and significantly improves fabric consistency and quality for woven or knitted fabric. 13 figs.

  16. Porous Silicon Structures as Optical Gas Sensors

    PubMed Central

    Levitsky, Igor A.

    2015-01-01

    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. PMID:26287199

  17. Integrated micro-electro-mechanical sensor development for inertial applications

    SciTech Connect

    Allen, J.J.; Kinney, R.D.; Sarsfield, J.

    1998-04-01

    Electronic sensing circuitry and micro electro mechanical sense elements can be integrated to produce inertial instruments for applications unheard of a few years ago. This paper will describe the Sandia M3EMS fabrication process, inertial instruments that have been fabricated, and the results of initial characterization tests of micro-machined accelerometers.

  18. Micro manipulator motion control to counteract macro manipulator structural vibrations

    SciTech Connect

    Lew, J.Y.; Trudnowski, D.J.; Evans, M.S.; Bennett, D.W.

    1995-02-01

    Inertial force damping control by micro manipulator modulation is proposed to suppress the vibrations of a micro/macro manipulator system. The proposed controller, developed using classical control theory, is added to the existing control system. The proposed controller uses real-time measurements of macro manipulator flexibility to adjust the motion of the micro manipulator to counteract structural vibrations. Experimental studies using an existing micro/macro flexible link manipulator testbed demonstrate the effectiveness of the proposed approach to suppression of vibrations in the macro/micro manipulator system using micro-manipulator-based inertial active damping control.

  19. Magnetic bead counter using a micro-Hall sensor for biological applications

    SciTech Connect

    Lee, W.; Kim, K.; Joo, S.; Kim, S.U.; Rhie, K.; Hong, J.; Shin, K-H.; and Kim, K.H.

    2009-04-13

    Micro-Hall sensors have been fabricated, and various numbers of micron-size magnetic beads have been placed within the sensor area. The Hall resistances measured at room temperature are found to be proportional to the number of the beads, and are in good agreement with the numerically simulated results presented in this study. Our sensors are designed to measure the number of beads between zero and full-scale signals for a given number range of interest. The effects of miniaturizing the beads and sensors to nanoscale are also discussed.

  20. Magnetic bead counter using a micro-Hall sensor for biological applications

    NASA Astrophysics Data System (ADS)

    Lee, Wonhyun; Joo, Sungjung; Kim, Sun Ung; Rhie, Kungwon; Hong, Jinki; Shin, Kyung-Ho; Kim, Ki Hyun

    2009-04-01

    Micro-Hall sensors have been fabricated, and various numbers of micron-size magnetic beads have been placed within the sensor area. The Hall resistances measured at room temperature are found to be proportional to the number of the beads, and are in good agreement with the numerically simulated results presented in this study. Our sensors are designed to measure the number of beads between zero and full-scale signals for a given number range of interest. The effects of miniaturizing the beads and sensors to nanoscale are also discussed.

  1. Micro optical fiber light source and sensor and method of fabrication thereof

    DOEpatents

    Kopelman, R.; Tan, W.; Shi, Z.Y.

    1994-11-01

    This invention relates generally to the development of and a method of fabricating a micro optical fiber light source. An optical fiber micro-light source is presented whose aperture is extremely small yet able to act as an intense light source. Light sources of this type have wide ranging applications, including use as micro-sensors in NSOM. Micro-sensor light sources have excellent detection limits as well as photo stability, reversibility, and millisecond response times. Furthermore, a method for manufacturing a micro optical fiber light source is provided. It involves the photo-chemical attachment of an optically active material onto the end surface of an optical fiber cable which has been pulled to form an end with an extremely narrow aperture. More specifically, photopolymerization has been applied as a means to photo-chemically attach an optically active material. This process allows significant control of the size of the micro light source. Furthermore, photo-chemically attaching an optically active material enables the implementation of the micro-light source in a variety of sensor applications. 4 figs.

  2. Micro optical fiber light source and sensor and method of fabrication thereof

    DOEpatents

    Kopelman, Raoul; Tan, Weihong; Shi, Zhong-You

    1994-01-01

    This invention relates generally to the development of and a method of fabricating a micro optical fiber light source. An optical fiber micro-light source is presented whose aperture is extremely small yet able to act as an intense light source. Light sources of this type have wide ranging applications, including use as micro-sensors in NSOM. Micro-sensor light sources have excellent detection limits as well as photo stability, reversibility, and millisecond response times. Furthermore, a method for manufacturing a micro optical fiber light source is provided. It involves the photo-chemical attachment of an optically active material onto the end surface of an optical fiber cable which has been pulled to form an end with an extremely narrow aperture. More specifically, photopolymerization has been applied as a means to photo-chemically attach an optically active material. This process allows significant control of the size of the micro light source. Furthermore, photo-chemically attaching an optically active material enables the implementation of the micro-light source in a variety of sensor applications.

  3. Micro-Hall magnetic sensors with high magnetic sensitivity based on III-V heterostructures

    NASA Astrophysics Data System (ADS)

    Del Medico, S.; Benyattou, Taha; Guillot, Gerard; Venet, T.; Gendry, Michel; Tardy, Jacques; Chovet, Alain

    1996-04-01

    In this work, we propose solutions based on engineering of III-V heterostructures to develop new types of semiconductor magnetic sensors. These micro-Hall sensors use the properties of a 2D electron gas and the benefit of pseudomorphic material, in which both the alloy composition and the built-in strain offer additional degrees of freedom for band structure tailoring, to exhibit high magnetic sensitivity, good linearity, low temperature coefficient and high resolution. With the growth optimization which is described, two pseudomorphic In0.75Ga0.25As/In0.52Al0.48As heterostructures were grown on a semi- insulating InP substrate by molecular beam epitaxy. To understand better the influence of the heterostructure design on its electronic properties, a model involving the self-consistent solution of the Poisson and Schrodinger equations using the Fermi-Dirac statistics has been developed. These results have been used to optimize the structure design. A magnetic sensitivity of 346 V/AT with a temperature coefficient of -230 ppm/ degree(s)C between -80 degree(s)C and 85 degree(s)C has been obtained. The device show good linearity against magnetic field and also against the supply current. High signal-to-noise ratios corresponding to minimal magnetic field of 350 nT/Hz1/2 at 100 Hz and 120 nT/Hz1/2 at 1 kHz have been measured.

  4. Fully front-side bulk-micromachined single-chip micro flow sensors for bare-chip SMT (surface mounting technology) packaging

    NASA Astrophysics Data System (ADS)

    Liu, Jiedan; Wang, Jiachou; Li, Xinxin

    2012-03-01

    This paper reports novel single-wafer-based piezoresistive micro flow sensors, which are bulk micromachined only from the front side of the silicon wafer to facilitate the sensor-bare chips directly packaged into micro-fluidic systems with low-cost surface mounting technology (SMT). With neither double-sided micromachining nor multiwafer bonding needed, two structural types of the piezoresistive flow sensors are designed and fabricated in (1 1 1) wafers, where ‘type A’ sensor has a smaller channel cross section area compared to ‘type B’ sensor. After the bare sensor chip directly attached on a printed circuit board (PCB), wire bonded between the pads and the PCB for electric interconnection and the inlet/outlet front side connected, deionized water is flowed into the both types of flow sensors to characterize piezoresistive output of the differential pressure sensing elements in terms of the flow rate. For ‘type A’ and ‘type B’ sensors that are both power supplied with DC 5 V, the sensitivities are sequentially measured as 766.80 mV (µL s-1)-1 and 19.12 mV (µL s-1)-1, with the nonlinearities as 0.4% FS and 0.9% FS, respectively. Compared with traditionally fabricated micro flow sensors, the single-chip fabricated differential-pressure flow sensors can be low-cost volume manufactured. Moreover, the bare sensor chips can be simply SMT packaged for low-cost micro-system applications.

  5. Solid state magnetic field sensors for micro unattended ground networks using spin dependent tunneling

    NASA Astrophysics Data System (ADS)

    Tondra, Mark; Nordman, Catherine A.; Lange, Erik H.; Reed, Daniel; Jander, Albrect; Akou, Seraphin; Daughton, James

    2001-09-01

    Micro Unattended Ground Sensor Networks will likely employ magnetic sensors, primarily for discrimination of objects as opposed to initial detection. These magnetic sensors, then, must fit within very small cost, size, and power budgets to be compatible with the envisioned sensor suites. Also, a high degree of sensitivity is required to minimize the number of sensor cells required to survey a given area in the field. Solid state magnetoresistive sensors, with their low cost, small size, and ease of integration, are excellent candidates for these applications assuming that their power and sensitivity performance are acceptable. SDT devices have been fabricated into prototype magnetic field sensors suitable for use in micro unattended ground sensor networks. They are housed in tiny SOIC 8-pin packages and mounted on a circuit board with required voltage regulation, signal amplification and conditioning, and sensor control and communications functions. The best sensitivity results to date are 289 pT/rt. Hz at 1 Hz, and and 7 pT/rt. Hz at f > 10 kHz. Expected near term improvements in performance would bring these levels to approximately 10 pT/rt Hz at 1 Hz and approximately 1 pT/rt. Hz at > 1 kHz.

  6. Fabry-Pérot cavity sensors for multipoint on-column micro gas chromatography detection.

    PubMed

    Liu, Jing; Sun, Yuze; Howard, Daniel J; Frye-Mason, Greg; Thompson, Aaron K; Ja, Shiou-Jyh; Wang, Siao-Kwan; Bai, Mengjun; Taub, Haskell; Almasri, Mahmoud; Fan, Xudong

    2010-06-01

    We developed and characterized a Fabry-Pérot (FP) sensor module based micro gas chromatography (microGC) detector for multipoint on-column detection. The FP sensor was fabricated by depositing a thin layer of metal and a layer of gas-sensitive polymer consecutively on the endface of an optical fiber, which formed the FP cavity. Light partially reflected from the metal layer and the polymer-air interface generated an interference spectrum, which shifted as the polymer layer absorbed the gas analyte. The FP sensor module was then assembled by inserting the FP sensor into a hole drilled in the wall of a fused-silica capillary, which can be easily connected to the conventional gas chromatography (GC) column through a universal quick seal column connector, thus enabling on-column real-time detection. We characterized the FP sensor module based microGC detector. Sensitive detection of various gas analytes was achieved with subnanogram detection limits. The rapid separation capability of the FP sensor module assembled with both single- and tandem-column systems was demonstrated, in which gas analytes having a wide range of polarities and volatilities were well-resolved. The tandem-column system obtained increased sensitivity and selectivity by employing two FP sensor modules coated with different polymers, showing great system versatility. PMID:20441156

  7. Magnetic sensor for building structural vibrations.

    PubMed

    García, Alfonso; Morón, Carlos; Tremps, Enrique

    2014-01-01

    This paper shows a new displacement-to-frequency transducer based on the variation of a coil inductance when a magnetic core is partially or completely inserted inside. This transducer is based on a Colpitts oscillator due its low manufacturing price, behavior and immunity to noise. A tank circuit with a configuration in parallel was used because it can be employed at lower frequencies and it enables it to make a direct analysis. The sensor has a dynamic range equal to the length of the coil. The cores can exchange sensors (coils with its ferromagnetic core) using the same electronic measuring system. In this way, with only an electronic circuit, the core sensor determines the measurement range. The obtained resolution is higher than 1/100,000, and the sensor also allows the measurement and knowing in real time the effect of vibration, thermal expansion, referred overload movements, etc.., that can occur in the structural elements of a building. PMID:24504104

  8. Magnetic Sensor for Building Structural Vibrations

    PubMed Central

    García, Alfonso; Morón, Carlos; Tremps, Enrique

    2014-01-01

    This paper shows a new displacement-to-frequency transducer based on the variation of a coil inductance when a magnetic core is partially or completely inserted inside. This transducer is based on a Colpitts oscillator due its low manufacturing price, behavior and immunity to noise. A tank circuit with a configuration in parallel was used because it can be employed at lower frequencies and it enables it to make a direct analysis. The sensor has a dynamic range equal to the length of the coil. The cores can exchange sensors (coils with its ferromagnetic core) using the same electronic measuring system. In this way, with only an electronic circuit, the core sensor determines the measurement range. The obtained resolution is higher than 1/100,000, and the sensor also allows the measurement and knowing in real time the effect of vibration, thermal expansion, referred overload movements, etc.., that can occur in the structural elements of a building. PMID:24504104

  9. Magnetic sensor for building structural vibrations.

    PubMed

    García, Alfonso; Morón, Carlos; Tremps, Enrique

    2014-02-05

    This paper shows a new displacement-to-frequency transducer based on the variation of a coil inductance when a magnetic core is partially or completely inserted inside. This transducer is based on a Colpitts oscillator due its low manufacturing price, behavior and immunity to noise. A tank circuit with a configuration in parallel was used because it can be employed at lower frequencies and it enables it to make a direct analysis. The sensor has a dynamic range equal to the length of the coil. The cores can exchange sensors (coils with its ferromagnetic core) using the same electronic measuring system. In this way, with only an electronic circuit, the core sensor determines the measurement range. The obtained resolution is higher than 1/100,000, and the sensor also allows the measurement and knowing in real time the effect of vibration, thermal expansion, referred overload movements, etc.., that can occur in the structural elements of a building.

  10. A micro resonant charge sensor with enhanced sensitivity based on differential sensing scheme and leverage mechanisms

    NASA Astrophysics Data System (ADS)

    Chen, Dongyang; Zhao, Jiuxuan; Xu, Zhonggui; Xie, Jin

    2016-10-01

    This letter reports a micro-electro-mechanical systems (MEMS) resonant charge sensor with enhanced sensitivity based on differential sensing scheme and leverage mechanisms. The sensor comprises two symmetrically-distributed double-ended tuning fork (DETF) resonators, each of which connects with dual micro-leverage mechanisms. The micro-leverages amplify electrostatic force in opposite directions and cause differential frequency shift of the two resonators. Both the resonators show a similar trend in behaviors of electrical and mechanical nonlinearity. Effect of environment disturbance is suppressed by the differential sensing scheme. The measured sensitivity of the two resonators are 3.31×10-4 Hz/fC2 and 1.85×10-4 Hz/fC2 respectively, and an overall sensitivity for the resonant charge sensor is 5.16×10-4 Hz/fC2.

  11. High-Throughput Functional MicroRNA Profiling Using Recombinant AAV-Based MicroRNA Sensor Arrays

    PubMed Central

    Tian, Wenhong; Dong, Xiaoyan; Wu, Xiaobing; Wu, Zhijian

    2014-01-01

    There is a lack of methods for high-throughput functional microRNA (miRNA) profiling. In this chapter, we describe a recombinant adeno-associated virus-based miRNA sensor array (miRNA Asensor array), which is able to profile functional miRNAs in cultured cells. The preparation of an miRNA Asensor array and its usage are discussed. PMID:24026702

  12. Sensor devices comprising field-structured composites

    DOEpatents

    Martin, James E.; Hughes, Robert C.; Anderson, Robert A.

    2001-02-27

    A new class of sensor devices comprising field-structured conducting composites comprising a textured distribution of conducting magnetic particles is disclosed. The conducting properties of such field-structured materials can be precisely controlled during fabrication so as to exhibit a large change in electrical conductivity when subject to any environmental influence which changes the relative volume fraction. Influences which can be so detected include stress, strain, shear, temperature change, humidity, magnetic field, electromagnetic radiation, and the presence or absence of certain chemicals. This behavior can be made the basis for a wide variety of sensor devices.

  13. Smart Sensors Assess Structural Health

    NASA Technical Reports Server (NTRS)

    2010-01-01

    NASA frequently inspects launch vehicles, fuel tanks, and other components for structural damage. To perform quick evaluation and monitoring, the Agency pursues the development of structural health monitoring systems. In 2001, Acellent Technologies Inc., of Sunnyvale, California, received Small Business Innovation Research (SBIR) funding from Marshall Space Flight Center to develop a hybrid Stanford Multi-Actuator Receiver Transduction (SMART) Layer for aerospace vehicles and structures. As a result, Acellent expanded the technology's capability and now sells it to aerospace and automotive companies; construction, energy, and utility companies; and the defense, space, transportation, and energy industries for structural condition monitoring, damage detection, crack growth monitoring, and other applications.

  14. Fiber-optic OCT sensor guided “SMART” micro-forceps for microsurgery

    PubMed Central

    Song, Cheol; Park, Dong Yong; Gehlbach, Peter L.; Park, Seong Jin; Kang, Jin U.

    2013-01-01

    A handheld Smart Micromanipulation Aided Robotic-surgery Tool (SMART) micro-forceps guided by a fiber-optic common-path optical coherence tomography (CP-OCT) sensor is presented. A fiber-optic CP-OCT distance and motion sensor is integrated into the shaft of a micro-forceps. The tool tip position is manipulated longitudinally through a closed loop control using a piezoelectric motor. This novel forceps design could significantly enhance safety, efficiency and surgical outcomes. The basic grasping and peeling functions of the micro-forceps are evaluated in dry phantoms and in a biological tissue model. As compared to freehand use, targeted grasping and peeling performance assisted by active tremor compensation, significantly improves micro-forceps user performance. PMID:23847730

  15. Evaluation of High-Precision Sensors in Structural Monitoring

    PubMed Central

    Erol, Bihter

    2010-01-01

    One of the most intricate branches of metrology involves the monitoring of displacements and deformations of natural and anthropogenic structures under environmental forces, such as tidal or tectonic phenomena, or ground water level changes. Technological progress has changed the measurement process, and steadily increasing accuracy requirements have led to the continued development of new measuring instruments. The adoption of an appropriate measurement strategy, with proper instruments suited for the characteristics of the observed structure and its environmental conditions, is of high priority in the planning of deformation monitoring processes. This paper describes the use of precise digital inclination sensors in continuous monitoring of structural deformations. The topic is treated from two viewpoints: (i) evaluation of the performance of inclination sensors by comparing them to static and continuous GPS observations in deformation monitoring and (ii) providing a strategy for analyzing the structural deformations. The movements of two case study objects, a tall building and a geodetic monument in Istanbul, were separately monitored using dual-axes micro-radian precision inclination sensors (inclinometers) and GPS. The time series of continuous deformation observations were analyzed using the Least Squares Spectral Analysis Technique (LSSA). Overall, the inclinometers showed good performance for continuous monitoring of structural displacements, even at the sub-millimeter level. Static GPS observations remained insufficient for resolving the deformations to the sub-centimeter level due to the errors that affect GPS signals. With the accuracy advantage of inclination sensors, their use with GPS provides more detailed investigation of deformation phenomena. Using inclinometers and GPS is helpful to be able to identify the components of structural responses to the natural forces as static, quasi-static, or resonant. PMID:22163499

  16. Evaluation of high-precision sensors in structural monitoring.

    PubMed

    Erol, Bihter

    2010-01-01

    One of the most intricate branches of metrology involves the monitoring of displacements and deformations of natural and anthropogenic structures under environmental forces, such as tidal or tectonic phenomena, or ground water level changes. Technological progress has changed the measurement process, and steadily increasing accuracy requirements have led to the continued development of new measuring instruments. The adoption of an appropriate measurement strategy, with proper instruments suited for the characteristics of the observed structure and its environmental conditions, is of high priority in the planning of deformation monitoring processes. This paper describes the use of precise digital inclination sensors in continuous monitoring of structural deformations. The topic is treated from two viewpoints: (i) evaluation of the performance of inclination sensors by comparing them to static and continuous GPS observations in deformation monitoring and (ii) providing a strategy for analyzing the structural deformations. The movements of two case study objects, a tall building and a geodetic monument in Istanbul, were separately monitored using dual-axes micro-radian precision inclination sensors (inclinometers) and GPS. The time series of continuous deformation observations were analyzed using the Least Squares Spectral Analysis Technique (LSSA). Overall, the inclinometers showed good performance for continuous monitoring of structural displacements, even at the sub-millimeter level. Static GPS observations remained insufficient for resolving the deformations to the sub-centimeter level due to the errors that affect GPS signals. With the accuracy advantage of inclination sensors, their use with GPS provides more detailed investigation of deformation phenomena. Using inclinometers and GPS is helpful to be able to identify the components of structural responses to the natural forces as static, quasi-static, or resonant. PMID:22163499

  17. Evaluation of high-precision sensors in structural monitoring.

    PubMed

    Erol, Bihter

    2010-01-01

    One of the most intricate branches of metrology involves the monitoring of displacements and deformations of natural and anthropogenic structures under environmental forces, such as tidal or tectonic phenomena, or ground water level changes. Technological progress has changed the measurement process, and steadily increasing accuracy requirements have led to the continued development of new measuring instruments. The adoption of an appropriate measurement strategy, with proper instruments suited for the characteristics of the observed structure and its environmental conditions, is of high priority in the planning of deformation monitoring processes. This paper describes the use of precise digital inclination sensors in continuous monitoring of structural deformations. The topic is treated from two viewpoints: (i) evaluation of the performance of inclination sensors by comparing them to static and continuous GPS observations in deformation monitoring and (ii) providing a strategy for analyzing the structural deformations. The movements of two case study objects, a tall building and a geodetic monument in Istanbul, were separately monitored using dual-axes micro-radian precision inclination sensors (inclinometers) and GPS. The time series of continuous deformation observations were analyzed using the Least Squares Spectral Analysis Technique (LSSA). Overall, the inclinometers showed good performance for continuous monitoring of structural displacements, even at the sub-millimeter level. Static GPS observations remained insufficient for resolving the deformations to the sub-centimeter level due to the errors that affect GPS signals. With the accuracy advantage of inclination sensors, their use with GPS provides more detailed investigation of deformation phenomena. Using inclinometers and GPS is helpful to be able to identify the components of structural responses to the natural forces as static, quasi-static, or resonant.

  18. Sensors, Volume 8, Micro- and Nanosensor Technology - Trends in Sensor Markets

    NASA Astrophysics Data System (ADS)

    Jones, Robert; Meixner, Hans

    1996-12-01

    Sensors is the first self-contained series to deal with the whole area of sensors. It describes general aspects, technical and physical fundamentals, construction, function, applications and developments of the various types of sensors. This final volume of the series uncovers trends in sensor technology and gives a comprehensive overview of the sensor market. The use of sensors in microsystems and in vacuum microelectronic as well as in acoustic wave devices is discussed. Present and emerging applications of sensors in aerospace, environmental, automotive, and medical industries, among others, are described. This volume is an indispensable reference work for both specialists and newcomers, researchers and developers

  19. Design and simulation of piezoelectric PZT micro-actuators with integrated piezoresistive displacement sensors for micro-optics applications

    NASA Astrophysics Data System (ADS)

    Chen, Ssu-Han; Michael, Aron; Kwok, Chee Yee; Wang, Peng

    2015-12-01

    This paper presents the design and simulation of a novel piezoelectric actuator integrated with on-chip piezoresistive sensors for micro-lens actuation. COMSOL Multiphysics is used to perform and facilitate the design and simulation. The actuator consists of eight d31 mode unimorph piezoelectric actuators symmetrically attached to a lens holding frame through springs at one end, and to the silicon substrate at the other end. Diffused p-Si piezoresistors with doping of 1x1018cm-3 are considered in the proposed design for displacement sensing of each micro-actuator. Results shows 3.2μm/V displacement sensitivity for the micro-lens actuator and piezoresistive sensitivity of 0.134mV/V/μm is obtainable with p-Si piezoresistors.

  20. Development of micro engine oil condition sensor using multi-wall carbon nanotube films

    NASA Astrophysics Data System (ADS)

    Na, Dae Seok; Jung-Ho Pak, James; Kyeong Kim, Jai

    2007-03-01

    A new interdigit-type micro oil condition sensor was designed and fabricated for monitoring the deterioration of lubricating and insulating oils. The designed sensor operates based on the change of the dielectric constant and electrical conductivity. In order to improve sensor performance, an oil condition sensor was fabricated using MEMS technology and multi-wall carbon nanotube film. The experiment was performed with automobile engine oils with the same brand and quality so as to ensure measurement reliability. Capacitance changes were measured according to increasing mileage and the sensors' performance was improved. These results show that the proposed sensor could measure the degree of oil deterioration with a high sensitivity and it is applicable to other lubricating systems as well as insulating systems.

  1. Capacitive Micro Pressure Sensor Integrated with a Ring Oscillator Circuit on Chip

    PubMed Central

    Dai, Ching-Liang; Lu, Po-Wei; Chang, Chienliu; Liu, Cheng-Yang

    2009-01-01

    The study investigates a capacitive micro pressure sensor integrated with a ring oscillator circuit on a chip. The integrated capacitive pressure sensor is fabricated using the commercial CMOS (complementary metal oxide semiconductor) process and a post-process. The ring oscillator is employed to convert the capacitance of the pressure sensor into the frequency output. The pressure sensor consists of 16 sensing cells in parallel. Each sensing cell contains a top electrode and a lower electrode, and the top electrode is a sandwich membrane. The pressure sensor needs a post-CMOS process to release the membranes after completion of the CMOS process. The post-process uses etchants to etch the sacrificial layers, and to release the membranes. The advantages of the post-process include easy execution and low cost. Experimental results reveal that the pressure sensor has a high sensitivity of 7 Hz/Pa in the pressure range of 0–300 kPa. PMID:22303167

  2. The detection of specific biomolecular interactions with micro-Hall magnetic sensors

    NASA Astrophysics Data System (ADS)

    Manandhar, Pradeep; Chen, Kan-Sheng; Aledealat, Khaled; Mihajlović, Goran; Yun, C. Steven; Field, Mark; Sullivan, Gerard J.; Strouse, Geoffrey F.; Bryant Chase, P.; von Molnár, Stephan; Xiong, Peng

    2009-09-01

    The detection of reagent-free specific biomolecular interactions through sensing of nanoscopic magnetic labels provides one of the most promising routes to biosensing with solid-state devices. In particular, Hall sensors based on semiconductor heterostructures have shown exceptional magnetic moment sensitivity over a large dynamic field range suitable for magnetic biosensing using superparamagnetic labels. Here we demonstrate the capability of such micro-Hall sensors to detect specific molecular binding using biotin-streptavidin as a model system. We apply dip-pen nanolithography to selectively biotinylate the active areas of InAs micro-Hall devices with nanoscale precision. Specific binding of complementarily functionalized streptavidin-coated superparamagnetic beads to the Hall crosses occurs via molecular recognition, and magnetic detection of the assembled beads is achieved at room temperature using phase sensitive micro-Hall magnetometry. The experiment constitutes the first unambiguous demonstration of magnetic detection of specific biomolecular interactions with semiconductor micro-Hall sensors, and the selective molecular functionalization and resulting localized bead assembly demonstrate the possibility of multiplexed sensing of multiple target molecules using a single device with an array of micro-Hall sensors.

  3. Self-Powered Triboelectric Micro Liquid/Gas Flow Sensor for Microfluidics.

    PubMed

    Chen, Jie; Guo, Hengyu; Zheng, Jiangeng; Huang, Yingzhou; Liu, Guanlin; Hu, Chenguo; Wang, Zhong Lin

    2016-08-23

    Liquid and gas flow sensors are important components of the micro total analysis systems (μTAS) for modern analytical sciences. In this paper, we proposed a self-powered triboelectric microfluidic sensor (TMS) by utilizing the signals produced from the droplet/bubble via the capillary and the triboelectrification effects on the liquid/solid interface for real-time liquid and gas flow detection. By alternating capillary with different diameters, the sensor's detecting range and sensitivity can be adjusted. Both the relationship between the droplet/bubble and capillary size, and the output signal of the sensor are systematically studied. By demonstrating the monitoring of the transfusion process for a patient and the gas flow produced from an injector, it shows that TMS has a great potential in building a self-powered micro total analysis system.

  4. Self-Powered Triboelectric Micro Liquid/Gas Flow Sensor for Microfluidics.

    PubMed

    Chen, Jie; Guo, Hengyu; Zheng, Jiangeng; Huang, Yingzhou; Liu, Guanlin; Hu, Chenguo; Wang, Zhong Lin

    2016-08-23

    Liquid and gas flow sensors are important components of the micro total analysis systems (μTAS) for modern analytical sciences. In this paper, we proposed a self-powered triboelectric microfluidic sensor (TMS) by utilizing the signals produced from the droplet/bubble via the capillary and the triboelectrification effects on the liquid/solid interface for real-time liquid and gas flow detection. By alternating capillary with different diameters, the sensor's detecting range and sensitivity can be adjusted. Both the relationship between the droplet/bubble and capillary size, and the output signal of the sensor are systematically studied. By demonstrating the monitoring of the transfusion process for a patient and the gas flow produced from an injector, it shows that TMS has a great potential in building a self-powered micro total analysis system. PMID:27490518

  5. Throughput optimization for laser micro structuring

    NASA Astrophysics Data System (ADS)

    Hoppius, Jan S.; Kanitz, A.; Gurevich, E. L.; Ostendorf, A.

    2016-03-01

    Laser pulses in the picosecond and femtosecond regime enable nearly non-thermal material processing where heat effects like molten pools and thermal tensions are often significantly reduced. However, a residual amount of laser energy transforms into heat. As a consequence cumulative multiple shot processing leads to heat accumulation and subsequently lower manufacturing accuracy. To increase the processing throughput without losing quality, it is important to optimize the laser pulse properties and the ablation strategy to further reduce thermal effects. Due to a low heat capacity in small structures, it is necessary to consider the substrate dimensions while performing micro- and nanoprocessing. In contrast to bulk material ablation, the heat dissipation is confined by the small heat capacity of microstructures. Especially for complex structures, it is time-consuming to find efficient processing parameters manually. For this reason, an in-situ evaluation system based on electrical resistivity measurements for on-line control of the ablation process was developed to optimize the laser parameters. In the work presented, the efficiency of 35 femtosecond pulsed laser ablation was evaluated on copper structures in the micrometer range. Furthermore, these results have been compared and evaluated with surface profiles measured by white-light interferometry.

  6. A Fiber Bragg Grating Sensing-Based Micro-Vibration Sensor and Its Application

    PubMed Central

    Li, Tianliang; Tan, Yuegang; Zhou, Zude

    2016-01-01

    This paper proposes a fiber Bragg grating sensing-based micro-vibration sensor. The optical fiber has been directly treated as an elastomer to design the micro-vibration sensor, which possesses two FBGs. The mass is fixed on the middle of the fiber, and the vertical vibration of the mass has been converted into the axial tension/compression of the fiber. The principle of the sensor has been introduced, and the experiment conclusions show that the sensor sensitivity is 2362 pm/g within the range of 200–1200 mm/s2, which is consistent with theoretical analysis sensitivity of 2532.6 pm/g, and it shows an excellent linearity of 1.376%, while the resonant frequency of the sensor is 34 Hz, and the flat frequency range resides in the 0–22 Hz range. When used to measure micro-vibrations, its measured frequency relative error is less than 1.69% compared with the values acquired with a MEMS accelerometer, and the amplitude values of its measured vibration signal are consistent with the MEMS accelerometer under different excitation conditions too, so it can effectively realize the micro-vibration measurements. PMID:27092507

  7. A Fiber Bragg Grating Sensing-Based Micro-Vibration Sensor and Its Application.

    PubMed

    Li, Tianliang; Tan, Yuegang; Zhou, Zude

    2016-01-01

    This paper proposes a fiber Bragg grating sensing-based micro-vibration sensor. The optical fiber has been directly treated as an elastomer to design the micro-vibration sensor, which possesses two FBGs. The mass is fixed on the middle of the fiber, and the vertical vibration of the mass has been converted into the axial tension/compression of the fiber. The principle of the sensor has been introduced, and the experiment conclusions show that the sensor sensitivity is 2362 pm/g within the range of 200-1200 mm/s², which is consistent with theoretical analysis sensitivity of 2532.6 pm/g, and it shows an excellent linearity of 1.376%, while the resonant frequency of the sensor is 34 Hz, and the flat frequency range resides in the 0-22 Hz range. When used to measure micro-vibrations, its measured frequency relative error is less than 1.69% compared with the values acquired with a MEMS accelerometer, and the amplitude values of its measured vibration signal are consistent with the MEMS accelerometer under different excitation conditions too, so it can effectively realize the micro-vibration measurements. PMID:27092507

  8. A Fiber Bragg Grating Sensing-Based Micro-Vibration Sensor and Its Application.

    PubMed

    Li, Tianliang; Tan, Yuegang; Zhou, Zude

    2016-04-15

    This paper proposes a fiber Bragg grating sensing-based micro-vibration sensor. The optical fiber has been directly treated as an elastomer to design the micro-vibration sensor, which possesses two FBGs. The mass is fixed on the middle of the fiber, and the vertical vibration of the mass has been converted into the axial tension/compression of the fiber. The principle of the sensor has been introduced, and the experiment conclusions show that the sensor sensitivity is 2362 pm/g within the range of 200-1200 mm/s², which is consistent with theoretical analysis sensitivity of 2532.6 pm/g, and it shows an excellent linearity of 1.376%, while the resonant frequency of the sensor is 34 Hz, and the flat frequency range resides in the 0-22 Hz range. When used to measure micro-vibrations, its measured frequency relative error is less than 1.69% compared with the values acquired with a MEMS accelerometer, and the amplitude values of its measured vibration signal are consistent with the MEMS accelerometer under different excitation conditions too, so it can effectively realize the micro-vibration measurements.

  9. A permalloy zigzag structure based magnetic bio-sensor

    NASA Astrophysics Data System (ADS)

    Ger, Tzong-Rong; Xu, You-Ren; Huang, Hao-Ting; Wei, Zung-Hang

    2012-04-01

    A magnetic fluid consisting of Fe3O4 magnetic nanoparticles is embedded inside cells by intracellular uptake. A micro-fabricated magnetic zigzag-shaped surface structure is studied for use as a biosensor. We have developed a MOKE magnetometer based methodology to measure the different hysteresis loop signals between cells with and without being placed on zigzag sensors. Adding the magnetic cells on the structure decreases the coercivity from the magneto-optical Kerr effect (MOKE) signal of zigzag magnetic thin films because of the magnetic properties of superparamagnetic nanoparticles. The magnetoresistance measurement observed is that the switching fields of the zigzag structure with magnetic cells are significantly increased compared to the case without cells in the hard axis of the external field applied.

  10. Modelling of micro-Hall sensors for magnetization imaging

    NASA Astrophysics Data System (ADS)

    Manzin, A.; Nabaei, V.

    2014-05-01

    This paper presents a numerical model for the study of micro-Hall magnetometry applications, aiming at evaluating the sensitivity of semiconductor miniaturized devices to the stray field of permalloy nanostructures with ring and disk geometry. The procedure couples a micromagnetic code, for the calculation of the stray field generated by the nanomagnet, to a 2D classical transport model for the determination of the electric potential distribution inside the Hall plate. The model is applied to study the sensitivity of a micro-Hall device in the detection of magnetization switching processes characterized by vortex state, focusing on the influence of magnetic nanostructure position.

  11. Injection moulding of optical functional micro structures using laser structured, PVD-coated mould inserts

    SciTech Connect

    Hopmann, Ch.; Weber, M.; Schöngart, M.; Schäfer, C.; Bobzin, K.; Bagcivan, N.; Brögelmann, T.; Theiß, S.; Münstermann, T.; Steger, M.

    2015-05-22

    Micro structured optical plastics components are intensively used i. e. in consumer electronics, for optical sensors in metrology, innovative LED-lighting or laser technology. Injection moulding has proven to be successful for the large-scale production of those parts. However, the production of those parts still causes difficulties due to challenges in the moulding and demoulding of plastics parts created with laser structured mould inserts. A complete moulding of the structures often leads to increased demoulding forces, which then cause a breaking of the structures and a clogging of the mould. An innovative approach is to combine PVD-coated (physical vapour deposition), laser structured inserts and a variothermal moulding process to create functional mic8iüro structures in a one-step process. Therefore, a PVD-coating is applied after the laser structuring process in order to improve the wear resistance and the anti-adhesive properties against the plastics melt. In a series of moulding trials with polycarbonate (PC) and polymethylmethacrylate (PMMA) using different coated moulds, the mould temperature during injection was varied in the range of the glass transition and the melt temperature of the polymers. Subsequently, the surface topography of the moulded parts is evaluated by digital 3D laser-scanning microscopy. The influence of the moulding parameters and the coating of the mould insert on the moulding accuracy and the demoulding behaviour are being analysed. It is shown that micro structures created by ultra-short pulse laser ablation can be successfully replicated in a variothermal moulding process. Due to the mould coating, significant improvements could be achieved in producing micro structured optical plastics components.

  12. Injection moulding of optical functional micro structures using laser structured, PVD-coated mould inserts

    NASA Astrophysics Data System (ADS)

    Hopmann, Ch.; Weber, M.; Schöngart, M.; Schäfer, C.; Bobzin, K.; Bagcivan, N.; Brögelmann, T.; Theiß, S.; Münstermann, T.; Steger, M.

    2015-05-01

    Micro structured optical plastics components are intensively used i. e. in consumer electronics, for optical sensors in metrology, innovative LED-lighting or laser technology. Injection moulding has proven to be successful for the large-scale production of those parts. However, the production of those parts still causes difficulties due to challenges in the moulding and demoulding of plastics parts created with laser structured mould inserts. A complete moulding of the structures often leads to increased demoulding forces, which then cause a breaking of the structures and a clogging of the mould. An innovative approach is to combine PVD-coated (physical vapour deposition), laser structured inserts and a variothermal moulding process to create functional mic8iüro structures in a one-step process. Therefore, a PVD-coating is applied after the laser structuring process in order to improve the wear resistance and the anti-adhesive properties against the plastics melt. In a series of moulding trials with polycarbonate (PC) and polymethylmethacrylate (PMMA) using different coated moulds, the mould temperature during injection was varied in the range of the glass transition and the melt temperature of the polymers. Subsequently, the surface topography of the moulded parts is evaluated by digital 3D laser-scanning microscopy. The influence of the moulding parameters and the coating of the mould insert on the moulding accuracy and the demoulding behaviour are being analysed. It is shown that micro structures created by ultra-short pulse laser ablation can be successfully replicated in a variothermal moulding process. Due to the mould coating, significant improvements could be achieved in producing micro structured optical plastics components.

  13. Feasibility study of micro-optical diffusion sensor based on laser-induced dielectrophoresis

    NASA Astrophysics Data System (ADS)

    Itani, K.; Ebisui, A.; Taguchi, Y.; Nagasaka, Y.

    2010-02-01

    A real-time monitoring of the diffusion coefficient using a micro sensing device is valuable for analyzing the dynamic change of protein-protein interactions and the protein conformation, such as the molecular size and the higher order structure. In the present study, we have developed a novel micro-optical diffusion sensor (MODS) based on a laserinduced dielectrophoresis (LIDEP) enabling small sample volume and high-speed measurement. This paper reports the measurement principle, chip design, and the validity of the proposed method. MODS consists of a pair of transparent electrodes and a photoconductive layer sealing the liquid sample. AC voltage is applied between transparent electrodes, and two excitation lasers are intersected on the photoconductive layer. The electrical conductivity distribution of the a- Si:H layer due to the photoconductive effect generates a non-uniform electric field followed by the dielectrophoresis (DEP), and then the concentration distribution is induced by LIDEP force. After cutting the AC voltage, the mass diffusion is occurred, and the diffusion coefficient can be obtained by observing the one dimensional diffusion process along with the interference fringe pattern. In the preliminary measurement, the prototype of the DEP cell was fabricated by the micro electro mechanical systems (MEMS) technique in order to verify the applicability of MODS, and we confirmed the lattice-shaped concentration distribution of polystyrene beads in distilled water. The decay time of the diffusion of the concentration distribution agreed well with the theoretical calculation. As a result, the applicability of MODS as the diffusion coefficient measurement method was verified.

  14. Structural Basis for microRNA Targeting

    PubMed Central

    Schirle, Nicole T.; Sheu-Gruttadauria, Jessica; MacRae, Ian J.

    2015-01-01

    Summary MicroRNAs (miRNAs) control expression of thousands of genes in plants and animals. miRNAs function by guiding Argonaute proteins to complementary sites in messenger RNAs (mRNAs) targeted for repression. We determined crystal structures of human Argonaute-2 (Ago2) bound to a defined guide RNA with and without target RNAs representing miRNA recognition sites. These structures suggest a stepwise mechanism, in which Ago2 primarily exposes guide nucleotides 2–5 for initial target pairing. Pairing to nt 2–5 promotes conformational changes that expose nt 2–8 and 13–16 for further target recognition. Interactions with the guide-target minor groove allow Ago2 to interrogate target RNAs in a sequence-independent manner, while an adenosine binding-pocket opposite guide nt 1 further facilitates target recognition. Spurious slicing of miRNA targets is avoided through an inhibitory coordination of one catalytic magnesium ion. These results explain the conserved nucleotide pairing patterns in animal miRNA target sites first observed over two decades ago. PMID:25359968

  15. A micro-Doppler sonar for acoustic surveillance in sensor networks

    NASA Astrophysics Data System (ADS)

    Zhang, Zhaonian

    Wireless sensor networks have been employed in a wide variety of applications, despite the limited energy and communication resources at each sensor node. Low power custom VLSI chips implementing passive acoustic sensing algorithms have been successfully integrated into an acoustic surveillance unit and demonstrated for detection and location of sound sources. In this dissertation, I explore active and passive acoustic sensing techniques, signal processing and classification algorithms for detection and classification in a multinodal sensor network environment. I will present the design and characterization of a continuous-wave micro-Doppler sonar to image objects with articulated moving components. As an example application for this system, we use it to image gaits of humans and four-legged animals. I will present the micro-Doppler gait signatures of a walking person, a dog and a horse. I will discuss the resolution and range of this micro-Doppler sonar and use experimental results to support the theoretical analyses. In order to reduce the data rate and make the system amenable to wireless sensor networks, I will present a second micro-Doppler sonar that uses bandpass sampling for data acquisition. Speech recognition algorithms are explored for biometric identifications from one's gait, and I will present and compare the classification performance of the two systems. The acoustic micro-Doppler sonar design and biometric identification results are the first in the field as the previous work used either video camera or microwave technology. I will also review bearing estimation algorithms and present results of applying these algorithms for bearing estimation and tracking of moving vehicles. Another major source of the power consumption at each sensor node is the wireless interface. To address the need of low power communications in a wireless sensor network, I will also discuss the design and implementation of ultra wideband transmitters in a three dimensional

  16. Selective binding and detection of magnetic labels using PHR sensor via photoresist micro-wells.

    PubMed

    Oh, Sunjong; Baek, Nam Seob; Jung, Sang-Don; Chung, Myung-Ae; Hung, Tran Quang; Anandakumar, S; Rani, V Sudha; Jeong, Jong-Ryul; Kim, CheolGi

    2011-05-01

    We have developed a novel platform for selective binding of magnetic labels on planar Hall resistance sensor (PHR) for biosensing applications. The photoresist (PR) micro wells were prepared on the PHR sensor junctions to trap the magnetic bead at specified locations on the sensor surface and thin layer of Au was sputtered in the PR wells immobilize bimolecular. The Au surface is functionalized with single-stranded oligonucleotide and further biotin was used to immobilize streptavidin coated magnetic labels (Dynabeads Myone 1.0 microm, Invitrogen Co.). After removal of the PR wells on the sensor surface the non specific binding magnetic labels were successfully removed and only the chemically bounded magnetic labels were remained on the Au surface for detection of biomolecules using PHR sensor. We controlled the number of magnetic labels on the PHR sensor surface by using different sizes of the PR well on the junctions. The specifically bounded magnetic labels were successfully detected by characterizing the individual PHR sensor junctions. This technique enables the complete control over the magnetic labels for selective binding of biomolecules on the sensor surface for increasing the sensitivity of the PHR sensor as well as removal of the non specific bindings on the sensor surface.

  17. Combined simulation of a micro permanent magnetic linear contactless displacement sensor.

    PubMed

    Gao, Jing; Müller, Wolfgang F O; Greiner, Felix; Eicher, Dirk; Weiland, Thomas; Schlaak, Helmut F

    2010-01-01

    The permanent magnetic linear contactless displacement (PLCD) sensor is a new type of displacement sensor operating on the magnetic inductive principle. It has many excellent properties and has already been used for many applications. In this article a Micro-PLCD sensor which can be used for microelectromechanical system (MEMS) measurements is designed and simulated with the CST EM STUDIO(®) software, including building a virtual model, magnetostatic calculations, low frequency calculations, steady current calculations and thermal calculations. The influence of some important parameters such as air gap dimension, working frequency, coil current and eddy currents etc. is studied in depth.

  18. Strain evaluation of strengthened concrete structures using FBG sensors

    NASA Astrophysics Data System (ADS)

    Lau, Kin-tak; Zhou, Li-min; Ye, Lin

    1999-12-01

    Fibre-optic Bragg Grating (FBG) sensor presents a great deal of potential in monitoring the internal status of the concrete structures after repairing or strengthening by an external adhered reinforcement. It can be used in a variety of configurations ranging from pointwise to multi-point strain measurement in order to investigate the strain distribution of the structures. In this paper, an experimental investigation on the rectangular notched-concrete beam, which was strengthened by glass fibre composites with the embedment of multiplexing FBG sensors is presented. Three point bending test was performed to investigate the strain profile of the specimen. Frequency modulated continuous wave (FMCW) technique was used to measure the strain variation of the fibre-grating regions. The results give a good agreement with the electrical resistance strain gauge in early loading condition. The difference of the strain-measuring results between the strain-gauge and FBG sensor was increased when further increasing the applied load. It was suspected that the micro/marco cracks occurred on the concrete surface and that the externally bonded strain-measuring device cannot be detected.

  19. Strain evaluation of strengthened concrete structures using FBG sensors

    SciTech Connect

    Lau Kintak; Zhou Limin; Ye Lin

    1999-12-02

    Fibre-optic Bragg Grating (FBG) sensor presents a great deal of potential in monitoring the internal status of the concrete structures after repairing or strengthening by an external adhered reinforcement. It can be used in a variety of configurations ranging from pointwise to multi-point strain measurement in order to investigate the strain distribution of the structures. In this paper, an experimental investigation on the rectangular notched-concrete beam, which was strengthened by glass fibre composites with the embedment of multiplexing FBG sensors is presented. Three point bending test was performed to investigate the strain profile of the specimen. Frequency modulated continuous wave (FMCW) technique was used to measure the strain variation of the fibre-grating regions. The results give a good agreement with the electrical resistance strain gauge in early loading condition. The difference of the strain-measuring results between the strain-gauge and FBG sensor was increased when further increasing the applied load. It was suspected that the micro/marco cracks occurred on the concrete surface and that the externally bonded strain-measuring device cannot be detected.

  20. Microscope-on-Chip Using Micro-Channel and Solid State Image Sensors

    NASA Technical Reports Server (NTRS)

    Wang, Yu

    2000-01-01

    Recently, Jet Propulsion Laboratory has invented and developed a miniature optical microscope, microscope-on-chip using micro-channel and solid state image sensors. It is lightweight, low-power, fast speed instrument, it has no image lens, does not need focus adjustment, and the total mass is less than 100g. A prototype has been built and demonstrated at JPL.

  1. Micro-Ares, An electric field sensor for ExoMars 2016

    NASA Astrophysics Data System (ADS)

    Déprez, G.; Montmessin, F.; Witasse, O.; Lapauw, L.; Vivat, F.; Abbaki, S.; Granier, P.; Moirin, D.; Trautner, R.; Hassen-Khodja, R.; d'Almeida, E.; Chardenal, L.; Berthelier, J.-J.; Espositi, F.; Debei, S.; Rafkin, S.; Barth, E.

    2015-10-01

    For the past few years, LATMOS has been involved in the development of Micro-ARES, an electric field sensor part of the science payload (DREAMS) of the ExoMars 2016 Schiaparelli entry, descent and landing demonstratormodule (EDM). It is dedicated to the very first measurement and characterization of the Martian atmospheric electricity.

  2. Study on digital closed-loop system of silicon resonant micro-sensor

    NASA Astrophysics Data System (ADS)

    Xu, Yefeng; He, Mengke

    2008-10-01

    Designing a micro, high reliability weak signal extracting system is a critical problem need to be solved in the application of silicon resonant micro-sensor. The closed-loop testing system based on FPGA uses software to replace hardware circuit which dramatically decrease the system's mass and power consumption and make the system more compact, both correlation theory and frequency scanning scheme are used in extracting weak signal, the adaptive frequency scanning arithmetic ensures the system real-time. The error model was analyzed to show the solution to enhance the system's measurement precision. The experiment results show that the closed-loop testing system based on FPGA has the personality of low power consumption, high precision, high-speed, real-time etc, and also the system is suitable for different kinds of Silicon Resonant Micro-sensor.

  3. In situ monitoring of temperature inside lithium-ion batteries by flexible micro temperature sensors.

    PubMed

    Lee, Chi-Yuan; Lee, Shuo-Jen; Tang, Ming-Shao; Chen, Pei-Chi

    2011-01-01

    Lithium-ion secondary batteries are commonly used in electric vehicles, smart phones, personal digital assistants (PDA), notebooks and electric cars. These lithium-ion secondary batteries must charge and discharge rapidly, causing the interior temperature to rise quickly, raising a safety issue. Over-charging results in an unstable voltage and current, causing potential safety problems, such as thermal runaways and explosions. Thus, a micro flexible temperature sensor for the in in-situ monitoring of temperature inside a lithium-ion secondary battery must be developed. In this work, flexible micro temperature sensors were integrated into a lithium-ion secondary battery using the micro-electro-mechanical systems (MEMS) process for monitoring temperature in situ.

  4. In situ monitoring of temperature inside lithium-ion batteries by flexible micro temperature sensors.

    PubMed

    Lee, Chi-Yuan; Lee, Shuo-Jen; Tang, Ming-Shao; Chen, Pei-Chi

    2011-01-01

    Lithium-ion secondary batteries are commonly used in electric vehicles, smart phones, personal digital assistants (PDA), notebooks and electric cars. These lithium-ion secondary batteries must charge and discharge rapidly, causing the interior temperature to rise quickly, raising a safety issue. Over-charging results in an unstable voltage and current, causing potential safety problems, such as thermal runaways and explosions. Thus, a micro flexible temperature sensor for the in in-situ monitoring of temperature inside a lithium-ion secondary battery must be developed. In this work, flexible micro temperature sensors were integrated into a lithium-ion secondary battery using the micro-electro-mechanical systems (MEMS) process for monitoring temperature in situ. PMID:22163735

  5. In Situ Monitoring of Temperature inside Lithium-Ion Batteries by Flexible Micro Temperature Sensors

    PubMed Central

    Lee, Chi-Yuan; Lee, Shuo-Jen; Tang, Ming-Shao; Chen, Pei-Chi

    2011-01-01

    Lithium-ion secondary batteries are commonly used in electric vehicles, smart phones, personal digital assistants (PDA), notebooks and electric cars. These lithium-ion secondary batteries must charge and discharge rapidly, causing the interior temperature to rise quickly, raising a safety issue. Over-charging results in an unstable voltage and current, causing potential safety problems, such as thermal runaways and explosions. Thus, a micro flexible temperature sensor for the in in-situ monitoring of temperature inside a lithium-ion secondary battery must be developed. In this work, flexible micro temperature sensors were integrated into a lithium-ion secondary battery using the micro-electro-mechanical systems (MEMS) process for monitoring temperature in situ. PMID:22163735

  6. Planar Hall effect sensor for magnetic micro- and nanobead detection

    NASA Astrophysics Data System (ADS)

    Ejsing, L.; Hansen, M. F.; Menon, A. K.; Ferreira, H. A.; Graham, D. L.; Freitas, P. P.

    2004-06-01

    Magnetic bead sensors based on the planar Hall effect in thin films of exchange-biased permalloy have been fabricated and characterized. Typical sensitivities are 3 μV/Oe mA. The sensor response to an applied magnetic field has been measured without and with coatings of commercially available 2 μm and 250 nm magnetic beads used for bioapplications (Micromer-M and Nanomag-D, Micromod, Germany). Detection of both types of beads and single bead detection of 2 μm beads is demonstrated, i.e., the technique is feasible for magnetic biosensors. Single 2 μm beads yield 300 nV signals at 10 mA and 15 Oe applied field.

  7. A Micro-Fabricated Force Sensor Using an All Thin Film Piezoelectric Active Sensor

    PubMed Central

    Lee, Junwoo; Choi, Wook; Yoo, Yong Kyoung; Hwang, Kyo Seon; Lee, Sang-Myung; Kang, Sungchul; Kim, Jinseok; Lee, Jeong Hoon

    2014-01-01

    The ability to measure pressure and force is essential in biomedical applications such as minimally invasive surgery (MIS) and palpation for detecting cancer cysts. Here, we report a force sensor for measuring a shear and normal force by combining an arrayed piezoelectric sensors layer with a precut glass top plate connected by four stress concentrating legs. We designed and fabricated a thin film piezoelectric force sensor and proposed an enhanced sensing tool to be used for analyzing gentle touches without the external voltage source used in FET sensors. Both the linear sensor response from 3 kPa to 30 kPa and the exact signal responses from the moving direction illustrate the strong feasibility of the described thin film miniaturized piezoelectric force sensor. PMID:25429407

  8. Development of Micro Air Reconnaissance Vehicle as a Test Bed for Advanced Sensors and Electronics

    NASA Technical Reports Server (NTRS)

    Shams, Qamar A.; Vranas, Thomas L.; Fox, Robert L.; Kuhn, Theodore R.; Ingham, John; Logan, Michael J.; Barnes, Kevin N.; Guenther, Benjamin F.

    2002-01-01

    This paper describes the development of a Micro/Mini Air Reconnaissance Vehicle for advanced sensors and electronics at NASA Langley Research Center over the last year. This vehicle is expected to have a total weight of less than four pounds, a design velocity of 40 mph, an endurance of 15-20 minutes, and a maximum range of 5km. The vehicle has wings that are simple to detach yet retain the correct alignment. The upper fuselage surface has a quick release hatch used to access the interior and also to mount the varying propulsion systems. The sensor suite developed for this vehicle consists of a Pitot-static measurement system for determining air speed, an absolute pressure measurement for determining altitude, magnetic direction measurement, and three orthogonal gyros to determine body angular rates. Swarming GPS-guidance and in-flight maneuvering is discussed, as well as design and installation of some other advance sensors like MEMS microphones, infrared cameras, GPS, humidity sensors, and an ultrasonic sonar sensor. Also low cost, small size, high performance control and navigation system for the Micro Air Vehicle is discussed. At the end, laboratory characterization of different sensors, motors, propellers, and batteries will be discussed.

  9. A micro-structured Si-based electrodes for high capacity electrical double layer capacitors

    NASA Astrophysics Data System (ADS)

    Krikscikas, Valdas; Oguchi, Hiroyuki; Yanazawa, Hiroshi; Hara, Motoaki; Kuwano, Hiroki

    2014-11-01

    We challenged to make basis for Si electrodes of electric double layer capacitors (EDLC) used as a power source of micro-sensor nodes. Mcroelectromechanical systems (MEMS) processes were successfully introduced to fabricate micro-structured Si-based electrodes to obtain high surface area which leads to high capacity of EDLCs. Study of fundamental properties revealed that the microstructured electrodes benefit from good wettability to electrolytes, but suffer from electric resistance. We found that this problem can be solved by metal-coating of the electrode surface. Finally we build an EDLC consisting of Au-coated micro-structured Si electrodes. This EDLC showed capacity of 14.3 mF/cm2, which is about 530 times larger than that of an EDLC consisting of flat Au electrodes.

  10. Design and experiment of spectrometer based on scanning micro-grating integrating with angle sensor

    NASA Astrophysics Data System (ADS)

    Biao, Luo; Wen, Zhi-yu

    2014-01-01

    A compact, low cost, high speed, non-destructive testing NIR (near infrared) spectrometer optical system based on MOEMS grating device is developed. The MOEMS grating works as the prismatic element and wavelength scanning element in our optical system. The MOEMS grating enables the design of compact grating spectrometers capable of acquiring full spectra using a single detector element. This MOEMS grating is driven by electromagnetic force and integrated with angle sensor which used to monitored deflection angle while the grating working. Comparing with the traditional spectral system, there is a new structure with a single detector and worked at high frequency. With the characteristics of MOEMS grating, the structure of the spectrometer system is proposed. After calculating the parameters of the optical path, ZEMAX optical software is used to simulate the system. According the ZEMAX output file of the 3D model, the prototype is designed by SolidWorks rapidly, fabricated. Designed for a wavelength range between 800 nm and 1500 nm, the spectrometer optical system features a spectral resolution of 16 nm with the volume of 97 mm × 81.7 mm × 81 mm. For the purpose of reduce modulated effect of sinusoidal rotation, spectral intensity of the different wavelength should be compensated by software method in the further. The system satisfies the demand of NIR micro-spectrometer with a single detector.

  11. Fully Self-Contained Vision-Aided Navigation and Landing of a Micro Air Vehicle Independent from External Sensor Inputs

    NASA Technical Reports Server (NTRS)

    Brockers, Roland; Susca, Sara; Zhu, David; Matthies, Larry

    2012-01-01

    Direct-lift micro air vehicles have important applications in reconnaissance. In order to conduct persistent surveillance in urban environments, it is essential that these systems can perform autonomous landing maneuvers on elevated surfaces that provide high vantage points without the help of any external sensor and with a fully contained on-board software solution. In this paper, we present a micro air vehicle that uses vision feedback from a single down looking camera to navigate autonomously and detect an elevated landing platform as a surrogate for a roof top. Our method requires no special preparation (labels or markers) of the landing location. Rather, leveraging the planar character of urban structure, the landing platform detection system uses a planar homography decomposition to detect landing targets and produce approach waypoints for autonomous landing. The vehicle control algorithm uses a Kalman filter based approach for pose estimation to fuse visual SLAM (PTAM) position estimates with IMU data to correct for high latency SLAM inputs and to increase the position estimate update rate in order to improve control stability. Scale recovery is achieved using inputs from a sonar altimeter. In experimental runs, we demonstrate a real-time implementation running on-board a micro aerial vehicle that is fully self-contained and independent from any external sensor information. With this method, the vehicle is able to search autonomously for a landing location and perform precision landing maneuvers on the detected targets.

  12. Efficient gas sensitivity in mixed bismuth ferrite micro (cubes) and nano (plates) structures

    SciTech Connect

    Waghmare, Shivaji D.; Jadhav, Vijaykumar V.; Gore, Shaym K.; Yoon, Seog-Joon; Ambade, Swapnil B.; Lokhande, B.J.; Mane, Rajaram S.; Han, Sung-Hwan

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ► Micro (cubes) structure embedded in nano (plates) of bismuth ferrite was prepared by a chemical method. ► These structures were characterized by XRD and SEM. ► LPG, CO{sub 2} and NH{sub 4} gases were exposed. ► Properties related to gas sensors were measured and reported. -- Abstract: Mixed micro (cubes) and nano (plates) structures of bismuth ferrite (BFO) have been synthesized by a simple and cost-effective wet-chemical method. Structural, morphological and phase confirmation characteristics are measured using X-ray diffraction, field-emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray analysis techniques. The digital FE-SEM photo-images of BFO sample confirmed an incubation of discrete micro-cubes into thin and regularly placed large number of nano-plates. The bismuth ferrite, with mixed structures, films show considerable performance when used in liquefied petroleum (LPG), carbon dioxide (CO{sub 2}) and ammonium (NH{sub 3}) gas sensors application. Different chemical entities in LPG have made it more efficient with higher sensitivity, recovery and response times compared to CO{sub 2} and NH{sub 3} gases. Furthermore, effect of palladium surface treatment on the gas sensitivity and the charge transfer resistances of BFO mixed structures is investigated and reported.

  13. Bottle micro-resonator temperature sensors for laser coolers

    NASA Astrophysics Data System (ADS)

    Nemova, Galina; Kashyap, Raman

    2016-03-01

    We show theoretically that a bottle resonator with a nanoscale altitude made on the surface of an optical fiber can be used as a temperature sensor for laser cooling of solids. The operation of such sensors is based on whispering gallery modes (WGMs). Bottle resonators can be made at different positions along the length of the fiber, which undergoes laser cooling. A smooth perturbation with a small nanoscale altitude on the surface of the fiber does not couple fiber modes propagating along the fiber axis and does not influence the laser cooling process. The temperature of the sample at each of these positions can be monitored as a shift in the dips seen in the transmission spectrum of a biconically tapered fiber placed perpendicular to the fiber axis on the top of the resonator to excite WGMs. Temperature sensitivities ~12pm/K and ~16pm/K are obtained for Yb3+:ZBLAN and Yb3+:YAG samples, respectively. The possibility of using bottle resonators for other applications is also discussed.

  14. A micro dew point sensor with a thermal detection principle

    NASA Astrophysics Data System (ADS)

    Kunze, M.; Merz, J.; Hummel, W.-J.; Glosch, H.; Messner, S.; Zengerle, R.

    2012-01-01

    We present a dew point temperature sensor with the thermal detection of condensed water on a thin membrane, fabricated by silicon micromachining. The membrane (600 × 600 × ~1 µm3) is part of a silicon chip and contains a heating element as well as a thermopile for temperature measurement. By dynamically heating the membrane and simultaneously analyzing the transient increase of its temperature it is detected whether condensed water is on the membrane or not. To cool the membrane down, a peltier cooler is used and electronically controlled in a way that the temperature of the membrane is constantly held at a value where condensation of water begins. This temperature is measured and output as dew point temperature. The sensor system works in a wide range of dew point temperatures between 1 K and down to 44 K below air temperature. In experimental investigations it could be proven that the deviation of the measured dew point temperatures compared to reference values is below ±0.2 K in an air temperature range of 22 to 70 °C. At low dew point temperatures of -20 °C (air temperature = 22 °C) the deviation increases to nearly -1 K.

  15. Identification of cross-country skiing movement patterns using micro-sensors.

    PubMed

    Marsland, Finn; Lyons, Keith; Anson, Judith; Waddington, Gordon; Macintosh, Colin; Chapman, Dale

    2012-01-01

    This study investigated the potential of micro-sensors for use in the identification of the main movement patterns used in cross-country skiing. Data were collected from four elite international and four Australian athletes in Europe and in Australia using a MinimaxX™ unit containing accelerometer, gyroscope and GPS sensors. Athletes performed four skating techniques and three classical techniques on snow at moderate velocity. Data from a single micro-sensor unit positioned in the centre of the upper back was sufficient to visually identify cyclical movement patterns for each technique. The general patterns for each technique were identified clearly across all athletes while at the same time distinctive characteristics for individual athletes were observed. Differences in speed, snow condition and gradient of terrain were not controlled in this study and these factors could have an effect on the data patterns. Development of algorithms to process the micro-sensor data into kinematic measurements would provide coaches and scientists with a valuable performance analysis tool. Further research is needed to develop such algorithms and to determine whether the patterns are consistent across a range of different speeds, snow conditions and terrain, and for skiers of differing ability.

  16. Identification of Cross-Country Skiing Movement Patterns Using Micro-Sensors

    PubMed Central

    Marsland, Finn; Lyons, Keith; Anson, Judith; Waddington, Gordon; Macintosh, Colin; Chapman, Dale

    2012-01-01

    This study investigated the potential of micro-sensors for use in the identification of the main movement patterns used in cross-country skiing. Data were collected from four elite international and four Australian athletes in Europe and in Australia using a MinimaxX™ unit containing accelerometer, gyroscope and GPS sensors. Athletes performed four skating techniques and three classical techniques on snow at moderate velocity. Data from a single micro-sensor unit positioned in the centre of the upper back was sufficient to visually identify cyclical movement patterns for each technique. The general patterns for each technique were identified clearly across all athletes while at the same time distinctive characteristics for individual athletes were observed. Differences in speed, snow condition and gradient of terrain were not controlled in this study and these factors could have an effect on the data patterns. Development of algorithms to process the micro-sensor data into kinematic measurements would provide coaches and scientists with a valuable performance analysis tool. Further research is needed to develop such algorithms and to determine whether the patterns are consistent across a range of different speeds, snow conditions and terrain, and for skiers of differing ability. PMID:22666075

  17. Single micro/nanowire pyroelectric nanogenerators as self-powered temperature sensors.

    PubMed

    Yang, Ya; Zhou, Yusheng; Wu, Jyh Ming; Wang, Zhong Lin

    2012-09-25

    We demonstrated the first application of a pyroelectric nanogenerator as a self-powered sensor (or active sensor) for detecting a change in temperature. The device consists of a single lead zirconate titanate (PZT) micro/nanowire that is placed on a thin glass substrate and bonded at its two ends, and it is packaged by polydimethylsiloxane (PDMS). By using the device to touch a heat source, the output voltage linearly increases with an increasing rate of change in temperature. The response time and reset time of the fabricated sensor are about 0.9 and 3 s, respectively. The minimum detecting limit of the change in temperature is about 0.4 K at room temperature. The sensor can be used to detect the temperature of a finger tip. The electricity generated under a large change in temperature can light up a liquid crystal display (LCD).

  18. Developments and Applications of Electrogenerated Chemiluminescence Sensors Based on Micro- and Nanomaterials

    PubMed Central

    Hazelton, Sandra G.; Zheng, Xingwang; Zhao, Julia Xiaojun; Pierce, David T.

    2008-01-01

    A variety of recent developments and applications of electrogenerated chemiluminescence (ECL) for sensors are described. While tris(2,2′-bipyridyl)-ruthenium(II) and luminol have dominated and continue to pervade the field of ECL-based sensors, recent work has focused on use of these lumophores with micro- and nanomaterials. It has also extended to inherently luminescent nanomaterials, such as quantum dots. Sensor configurations including microelectrode arrays and microfluidics are reviewed and, with the recent trend toward increased use of nanomaterials, special attention has been given to sensors which include thin films, nanoparticles and nanotubes. Applications of ECL labels and examples of label-free sensing that incorporate nanomaterials are also discussed.

  19. Laser surface micro-/nano-structuring by a simple transportable micro-sphere lens array

    NASA Astrophysics Data System (ADS)

    Sedao, Xxx; Derrien, Thibault J.-Y.; Romer, Gert-willem R. B. E.; Pathiraj, Belavendram; Huis in `t Veld, Albertus J.

    2012-11-01

    A micro-sphere array optic was employed for laser surface micro-structuring. This array optic consists of a hexagonally close-packed monolayer of silica micro-spheres. It was organized through a self-assembly process and held together on a glass support, without using any adhesives. The array assembly was then reversed, placed in direct contact with the substrate and exposed to 515 nm, 6.7 ps laser pulses. During the exposure, the silica spheres act as micro-lenses, which enhance the near-field light intensity underneath them. As the spheres are confined in the space between the substrate and glass support, they are not ejected during laser machining. Using this type of direct write laser machining, a large number of identical features (nano-holes) can be produced in parallel simultaneously. The holes drilled are a few hundred nanometres in diameter and the depth depends on the number of laser pulses applied. The impact of laser machining on the micro-spheres was also studied. The micro-spheres were contaminated or partially damaged after micro-structuring. Combination of a moderate laser pulse energy and multiple shots was found to ensure a good surface structuring quality and minimum damage to the spherical particles.

  20. Application of an evolutionary algorithm in the optimal design of micro-sensor.

    PubMed

    Lu, Qibing; Wang, Pan; Guo, Sihai; Sheng, Buyun; Liu, Xingxing; Fan, Zhun

    2015-01-01

    This paper introduces an automatic bond graph design method based on genetic programming for the evolutionary design of micro-resonator. First, the system-level behavioral model is discussed, which based on genetic programming and bond graph. Then, the geometry parameters of components are automatically optimized, by using the genetic algorithm with constraints. To illustrate this approach, a typical device micro-resonator is designed as an example in biomedicine. This paper provides a new idea for the automatic optimization design of biomedical sensors by evolutionary calculation.

  1. Silicon sensors with pyramidal structures for neutron imaging

    NASA Astrophysics Data System (ADS)

    Kok, A.; Kohout, Z.; Hansen, T.-E.; Petersson, S.; Pospisil, S.; Rokne, J.; Slavicek, T.; Soligard, S.; Thungstrom, G.; Vykydal, Z.

    2014-04-01

    Neutron detection is a valuable tool in nuclear science research, homeland security, quality assurance in nuclear plants and medical applications. Recent developments and near future instrumentations in neutron imaging have a need for sensors with high spatial resolution, dynamic range, sensitivity and background discrimination. Silicon based neutron detectors can potentially fulfil these requirements. In this work, pad and pixel detectors with pyramidal micro-structures have been successfully fabricated that should have an improved detection efficiency when compared to conventional planar devices. Titanium di-boride (TiB2) and lithium fluoride (LiF) were deposited as the neutron converters. Excellent electrical performances were measured on both simple pad and pixel detectors. A selection of pad detectors was examined by alpha spectroscopy. Measurement with thermal neutrons from a 241Am-Be source shows an improvement in relative efficiency of up to 38% when compared to conventional planar devices.

  2. Biologically inspired, haltere, angular-rate sensors for micro-autonomous systems

    NASA Astrophysics Data System (ADS)

    Smith, G. L.; Bedair, S. S.; Schuster, B. E.; Nothwang, W. D.; Pulskamp, J. S.; Meyer, C. D.; Polcawich, R. G.

    2012-06-01

    Small autonomous aerial systems require the ability to detect roll, pitch, and yaw to enable stable flight. Existing inertial measurement units (IMUs) are incapable of accurately measuring roll-pitch-yaw within the size, weight, and power requirements of at-scale insect-inspired aerial autonomous systems. To overcome this, we have designed novel IMUs based on the biological haltere system in a microelectromechanical system (MEMS). MEMS haltere sensors were successfully simulated, designed, and fabricated with a control scheme that enables simple, straightforward decoupling of the signals. Passive mechanical logic was designed to facilitate the decoupling of the forces acting on the sensor. The control scheme was developed that efficiently and accurately decouples the three component parts from the haltere sensors. Individual, coupled, and arrayed halteres were fabricated. A series of static electrical tests and dynamic device tests were conducted, in addition to in-situ bend tests, to validate the simulation results, and these, taken as a whole, indicate that the MEMS haltere sensors will be inherently sensitive to the Coriolis forces caused by changes in angular rate. The successful fabrication of a micro-angular rate sensor represents a substantial breakthrough and is an enabling technology for a number of Army applications, including micro air vehicles (MAVs).

  3. Fault diagnosis for micro-gas turbine engine sensors via wavelet entropy.

    PubMed

    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.

  4. Fault Diagnosis for Micro-Gas Turbine Engine Sensors via Wavelet Entropy

    PubMed Central

    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. PMID:22163734

  5. Effect of structural heat conduction on the performance of micro-combustors and micro-thrusters

    NASA Astrophysics Data System (ADS)

    Leach, Timothy Thierry

    This thesis investigates the effect of gas-structure interaction on the design and performance of miniaturized combustors with characteristic dimensions less than a few millimeters. These are termed 'micro-combustors' and are intended for use in devices ranging from micro-scale rocket motors for micro, nano, and pico-satellite propulsion, to micro-scale engines for micro-Unmanned Air Vehicle (UAV) propulsion and compact power generation. Analytical models for the propagation of a premixed laminar flame in a micro-channel are developed. The models' predictions are compared to the results of more detailed numerical simulations that incorporate multi-step chemistry, distributed heat transfer between the reacting gas and the combustor structure, heat transfer between the combustor and the environment, and heat transfer within the combustor structure. The results of the modeling and simulation efforts are found to be in good qualitative agreement and demonstrate that the behavior of premixed laminar flames in micro-channels is governed by heat transfer within the combustor structure and heat loss to the environment. The key findings of this work are as follows: First, heat transfer through the micro-combustor's structure tends to increase the flame speed and flame thickness. The increase in flame thickness with decreasing passage height suggests that micro-scale combustors will need to be longer than their conventional-scale counterparts. However, the increase in flame speed more than compensates for this effect and the net effect is that miniaturizing a combustor can increase its power density substantially. Second, miniaturizing chemical rocket thrusters can substantially increase thrust/weight ratio but comes at the price of reduced specific impulse (i.e. overall efficiency). Third, heat transfer through the combustor's structure increases steady-state and transient flame stability. This means that micro-scale combustors will be more stable than their conventional

  6. Coupled sensor/platform control design for low-level chemical detection with position-adaptive micro-UAVs

    NASA Astrophysics Data System (ADS)

    Goodwin, Thomas; Carr, Ryan; Mitra, Atindra K.; Selmic, Rastko R.

    2009-05-01

    We discuss the development of Position-Adaptive Sensors [1] for purposes for detecting embedded chemical substances in challenging environments. This concept is a generalization of patented Position-Adaptive Radar Concepts developed at AFRL for challenging conditions such as urban environments. For purposes of investigating the detection of chemical substances using multiple MAV (Micro-UAV) platforms, we have designed and implemented an experimental testbed with sample structures such as wooden carts that contain controlled leakage points. Under this general concept, some of the members of a MAV swarm can serve as external position-adaptive "transmitters" by blowing air over the cart and some of the members of a MAV swarm can serve as external position-adaptive "receivers" that are equipped with chemical or biological (chem/bio) sensors that function as "electronic noses". The objective can be defined as improving the particle count of chem/bio concentrations that impinge on a MAV-based position-adaptive sensor that surrounds a chemical repository, such as a cart, via the development of intelligent position-adaptive control algorithms. The overall effect is to improve the detection and false-alarm statistics of the overall system. Within the major sections of this paper, we discuss a number of different aspects of developing our initial MAV-Based Sensor Testbed. This testbed includes blowers to simulate position-adaptive excitations and a MAV from Draganfly Innovations Inc. with stable design modifications to accommodate our chem/bio sensor boom design. We include details with respect to several critical phases of the development effort including development of the wireless sensor network and experimental apparatus, development of the stable sensor boom for the MAV, integration of chem/bio sensors and sensor node onto the MAV and boom, development of position-adaptive control algorithms and initial tests at IDCAST (Institute for the Development and

  7. Fiber optic sensor technology - An opportunity for smart aerospace structures

    NASA Technical Reports Server (NTRS)

    Heyman, J. S.; Rogowski, R. S.; Claus, R. O.

    1988-01-01

    Fiber optic sensors provide the opportunity for fabricating materials with internal sensors which can serve as lifetime health monitors, analogous to a central nervous system. The embedded fiber optic sensors can be interrogated by various techniques to measure internal strain, temperature, pressure, acoustic waves and other parameters indicative of structural integrity. Experiments have been conducted with composite samples with embedded sensors to measure strain using optical time domain reflectometry, modal interference and an optical phase locked loop. Fiber optic sensors have been developed to detect acoustic emission and impact damage and have been demonstrated for cure monitoring. These sensors have the potential for lifetime monitoring of structural properties, providing real time nondestructive evaluation.

  8. Optical fiber axial micro-displacement sensor based on Mach-Zehnder interferometer.

    PubMed

    Shen, Changyu; Wang, Youqing; Chu, Jinlei; Lu, Yanfang; Li, Yi; Dong, Xinyong

    2014-12-29

    A Mach-Zehnder interferometer (MZI) based fiber axial micro-displacement sensor was proposed. The MZI was constructed by a bowknot-type taper (BTT) combining with a fiber core-offset between two single mode fibers (SMFs). The axial micro-displacement of the core offset is correlated with the MZI transmission spectrum and varied with the interferometer arm length. For the arm length L of 12, 18, 24 and 30 mm, the proposed sensors showed high sensitivity of -0.362 dB/μm, -0.385 dB/μm, -0.332 dB/μm and -0.235dB/μm, and temperature errors of -0.056 dB/°C, -0.036 dB/°C, -0.044 dB/°C, -0.048 dB/°C, respectively. The theoretical simulations of the energy distributions were also given. The obtained sensitivity of -0.385 dB/μm is about 150 times high than that of the current similar existing axial micro-displacement sensor. PMID:25607166

  9. Dimensionality aspects of nano micro integrated metal oxide based early stage leak detection room temperature hydrogen sensor

    NASA Astrophysics Data System (ADS)

    Deshpande, Sameer Arun

    Detection of explosive gas leaks such as hydrogen (H2) becomes key element in the wake of counter-terrorism threats, introduction of hydrogen powered vehicles and use of hydrogen as a fuel for space explorations. In recent years, a significant interest has developed on metal oxide nanostructured sensors for the detection of hydrogen gas. Gas sensors properties such as sensitivity, selectivity and response time can be enhanced by tailoring the size, the shape, the structure and the surface of the nanostructures. Sensor properties (sensitivity, selectivity and response time) are largely modulated by operating temperature of the device. Issues like instability of nanostructures at high temperature, risk of hydrogen explosion and high energy consumption are driving the research towards detection of hydrogen at low temperatures. At low temperatures adsorption of O2- species on the sensor surface instead of O- (since O- species reacts easily with hydrogen) result in need of higher activation energy for hydrogen and adsorbed species interaction. This makes hydrogen detection at room temperature a challenging task. Higher surface area to volume ratio (resulting higher reaction sites), enhanced electronic properties by varying size, shape and doping foreign impurities (by modulating space charge region) makes nanocrystalline materials ideal candidate for room temperature gas sensing applications. In the present work various morphologies of nanostructured tin oxide (SnO 2) and indium (In) doped SnO2 and titanium oxide (titania, TiO2) were synthesized using sol-gel, hydrothermal, thermal evaporation techniques and successfully integrated with the micro-electromechanical devices H2 at ppm-level (as low as 100ppm) has been successfully detected at room temperature using the SnO2 nanoparticles, SnO2 (nanowires) and TiO2 (nanotubes) based MEMS sensors. While sensor based on indium doped tin oxide showed the highest sensitivity (S =Ra/Rg= 80000) and minimal response time (10sec

  10. Micro-patterning of Mammalian Cells on Suspended MEMS Resonant Sensors for Long-Term Growth Measurements

    PubMed Central

    Corbin, Elise A.; Dorvel, Brian R.; Millet, Larry J.; King, William P.; Bashir, Rashid

    2014-01-01

    MEMS resonant mass sensors can measure the mass of individual cells, though long-term growth measurements are limited by the movement of cells off the sensor area. Micro-patterning techniques are a powerful approach to control the placement of individual cells in an arrayed format. In this work we present a method for micro-patterning cells on fully suspended resonant sensors through select functionalization and passivation of the chip surface. This method combines high-resolution photolithography with a blanket transfer technique for applying photoresist to avoid damaging the sensors. Cells are constrained to the patterned collagen area on the sensor by pluronic acting as a cell adhesion blocker. This micro-patterning method enables long-term growth measurements, which is demonstrated by a measurement of the change in mass of a human breast cancer cell over 18 h. PMID:24535001

  11. Recent Trends in Monitoring of European Water Framework Directive Priority Substances Using Micro-Sensors: A 2007–2009 Review

    PubMed Central

    Namour, Philippe; Lepot, Mathieu; Jaffrezic-Renault, Nicole

    2010-01-01

    This review discusses from a critical perspective the development of new sensors for the measurement of priority pollutants targeted in the E.U. Water Framework Directive. Significant advances are reported in the paper and their advantages and limitations are also discussed. Future perspectives in this area are also pointed out in the conclusions. This review covers publications appeared since December 2006 (the publication date of the Swift report). Among priority substances, sensors for monitoring the four WFD metals represent 81% of published papers. None of analyzed publications present a micro-sensor totally validated in laboratory, ready for tests under real conditions in the field. The researches are mainly focused on the sensing part of the micro-sensors. Nevertheless, the main factor limiting micro-sensor applications in the environment is the ruggedness of the receptor towards environmental conditions. This point constitutes the first technological obstacle to be overcome for any long-term field tests. PMID:22163635

  12. A beam-membrane structure micromachined differential pressure flow sensor.

    PubMed

    Chen, P; Zhao, Y L; Tian, B; Li, C; Li, Y Y

    2015-04-01

    A beam-membrane structure micromachined flow sensor is designed, depending on the principle of differential pressure caused by the mass flow, which is directly proportional to the square flow rate. The FSI (fluid structure interaction) characteristics of the differential pressure flow sensor are investigated via numerical analysis and analog simulation. The working mechanism of the flow sensor is analyzed depending on the FSI results. Then, the flow sensor is fabricated and calibrated. The calibration results show that the beam-membrane structure differential pressure flow sensor achieves ideal static characteristics and works well in the practical applications.

  13. A beam-membrane structure micromachined differential pressure flow sensor

    SciTech Connect

    Chen, P.; Zhao, Y. L.; Tian, B. Li, C.; Li, Y. Y.

    2015-04-15

    A beam-membrane structure micromachined flow sensor is designed, depending on the principle of differential pressure caused by the mass flow, which is directly proportional to the square flow rate. The FSI (fluid structure interaction) characteristics of the differential pressure flow sensor are investigated via numerical analysis and analog simulation. The working mechanism of the flow sensor is analyzed depending on the FSI results. Then, the flow sensor is fabricated and calibrated. The calibration results show that the beam-membrane structure differential pressure flow sensor achieves ideal static characteristics and works well in the practical applications.

  14. Multi-sensor fusion techniques for state estimation of micro air vehicles

    NASA Astrophysics Data System (ADS)

    Donavanik, Daniel; Hardt-Stremayr, Alexander; Gremillion, Gregory; Weiss, Stephan; Nothwang, William

    2016-05-01

    Aggressive flight of micro air vehicles (MAVs) in unstructured, GPS-denied environments poses unique challenges for estimation of vehicle pose and velocity due to the noise, delay, and drift in individual sensor measurements. Maneuvering flight at speeds in excess of 5 m/s poses additional challenges even for active range sensors; in the case of LIDAR, an assembled scan of the vehicles environment will in most cases be obsolete by the time it is processed. Multi-sensor fusion techniques which combine inertial measurements with passive vision techniques and/or LIDAR have achieved breakthroughs in the ability to maintain accurate state estimates without the use of external positioning sensors. In this paper, we survey algorithmic approaches to exploiting sensors with a wide range of nonlinear dynamics using filter and bundle-adjustment based approaches for state estimation and optimal control. From this foundation, we propose a biologically-inspired framework for incorporating the human operator in the loop as a privileged sensor in a combined human/autonomy paradigm.

  15. Detection of single magnetic bead using InAs micro-Hall sensors for biological applications

    NASA Astrophysics Data System (ADS)

    Mihajlovic, Goran; Ohtani, Keita; Field, Mark

    2005-03-01

    We have fabricated and characterized micro-Hall sensors from InAs/AlSb quantum well heterostructures containing a two-dimensional electron gas. The sensors exhibit room temperature field sensitivities as high as 600 φ/T, mobilities >2x10^4 cm^2/V.s and low 1/f noise which result in an average field resolution down to the sub- gauss range. Measurements were carried out at temperatures below 150 K on a single submicron superparamagnetic bead (d˜0.9 μm) that are intended to be used as magnetic labels in biological applications [1]. The magnetization showed expected Langevin behavior as a function of applied field with good signal to noise ratio, demonstrating good potential for the sensors to be used as a detection tool in biological applications. We have also measured the magnetic hysteresis for a single ferromagnetic Ni nanowire (d ˜ 200nm) using the device. Our ongoing efforts to demonstrate room temperature operation and to develop biocompatible detection schemes utilizing the micro-Hall sensors will be presented. This work was supported by NSF NIRT Grant ECS-0210332 [1] Q. A. Pankhurst et al., J. Phys. D 36 R167 (2003) .

  16. Reverse replication of circular micro grating structures with soft lithography

    NASA Astrophysics Data System (ADS)

    Shang, Xiaobing; Missinne, Jeroen; Teigell Beneitez, Nuria; Jablonski, Michal; De Smet, Jelle; Joshi, Pankaj; Cuypers, Dieter; Baghdasaryan, Tigran; Vervaeke, Michael; Thienpont, Hugo; De Smet, Herbert

    2015-09-01

    In this work, the reverse replication of circular micro grating structures on glass substrates is implemented using an ultra-violet curable resin and a polydimethylsiloxane (PDMS) mold which has the same structure as the original circular grating master. Two different techniques ("double PDMS replication" and "polymer- PDMS replication") are employed to fabricate those reversed circular micro grating structures. Surface profiling measurements show that in case of the polymer-PDMS replication the dimensions of the resulting circular grating structures closely approximate those of the master, while the grating height is slightly decreased in case of the double PDMS replication technique, mainly due to the use of the releasing agent. For both methods, the grating slopes of the circular gratings are almost unchanged, leading to the desired optical performance. The two techniques are quite useful for more accurate reverse replications of micro optical and photonic structures.

  17. Dynamic Structural Health Monitoring of Slender Structures Using Optical Sensors

    PubMed Central

    Antunes, Paulo; Travanca, Rui; Rodrigues, Hugo; Melo, José; Jara, José; Varum, Humberto; André, Paulo

    2012-01-01

    In this paper we summarize the research activities at the Instituto de Telecomunicações—Pólo de Aveiro and University of Aveiro, in the field of fiber Bragg grating based sensors and their applications in dynamic measurements for Structural Health Monitoring of slender structures such as towers. In this work we describe the implementation of an optical biaxial accelerometer based on fiber Bragg gratings inscribed on optical fibers. The proof-of-concept was done with the dynamic monitoring of a reinforced concrete structure and a slender metallic telecommunication tower. Those structures were found to be suitable to demonstrate the feasibility of FBG accelerometers to obtain the structures' natural frequencies, which are the key parameters in Structural Health Monitoring and in the calibration of numerical models used to simulate the structure behavior. PMID:22778661

  18. Photonic Crystal Structures with Tunable Structure Color as Colorimetric Sensors

    PubMed Central

    Wang, Hui; Zhang, Ke-Qin

    2013-01-01

    Colorimetric sensing, which transduces environmental changes into visible color changes, provides a simple yet powerful detection mechanism that is well-suited to the development of low-cost and low-power sensors. A new approach in colorimetric sensing exploits the structural color of photonic crystals (PCs) to create environmentally-influenced color-changeable materials. PCs are composed of periodic dielectrics or metallo-dielectric nanostructures that affect the propagation of electromagnetic waves (EM) by defining the allowed and forbidden photonic bands. Simultaneously, an amazing variety of naturally occurring biological systems exhibit iridescent color due to the presence of PC structures throughout multi-dimensional space. In particular, some kinds of the structural colors in living organisms can be reversibly changed in reaction to external stimuli. Based on the lessons learned from natural photonic structures, some specific examples of PCs-based colorimetric sensors are presented in detail to demonstrate their unprecedented potential in practical applications, such as the detections of temperature, pH, ionic species, solvents, vapor, humidity, pressure and biomolecules. The combination of the nanofabrication technique, useful design methodologies inspired by biological systems and colorimetric sensing will lead to substantial developments in low-cost, miniaturized and widely deployable optical sensors. PMID:23539027

  19. Elemental analyses of hypervelocity micro-particle impact sites on interplanetary dust experiment sensor surfaces

    NASA Technical Reports Server (NTRS)

    Simon, Charles G.; Hunter, J. L.; Griffis, D. P.; Misra, V.; Ricks, D. R.; Wortman, Jim J.

    1992-01-01

    The Interplanetary Dust Experiment (IDE) had over 450 electrically active ultra-high purity metal-oxide-silicon impact detectors located on the six primary sides of the Long Duration Exposure Facility (LDEF). Hypervelocity micro-particles that struck the active sensors with enough energy to breakdown the 0.4 to 1.0 micron thick SiO2 insulator layer separating the silicon base (the negative electrode), and the 1000 A thick surface layer of aluminum (the positive electrode) caused electrical discharges that were recorded for the first year of orbit. These discharge features, which include 50 micron diameter areas where the aluminum top layer has been vaporized, facilitate the location of the impacts. The high purity Al-SiO2-Si substrates allow detection of trace (ppm) amounts of hypervelocity impactor residues. After sputtering through a layer of surface contamination, secondary ion mass spectrometry (SIMS) is used to create two-dimensional elemental ion intensity maps of micro-particle impact sites on the IDE sensors. The element intensities in the central craters of the impacts are corrected for relative ion yields and instrumental conditions and then normalized to silicon. The results are used to classify the particles' origins as 'manmade', 'natural' or 'indeterminate'. The last classification results from the presence of too little impactor residue (a frequent occurrence on leading edge impacts), analytical interference from high background contamination, the lack of information on silicon residue, the limited usefulness of data on aluminum in the central craters, or a combination of these circumstances. Several analytical 'blank' discharges were induced on flight sensors by pressing down on the sensor surface with a pure silicon shard. Analyses of these blank discharges showed that the discharge energy blasts away the layer of surface contamination. Only Si and Al were detected inside the discharge zones, including the central craters, of these features. A

  20. A radar unattended ground sensor with micro-Doppler capabilities for false alarm reduction

    NASA Astrophysics Data System (ADS)

    Tahmoush, Dave; Silvious, Jerry; Burke, Ed

    2010-10-01

    Unattended ground sensors (UGS) provide the capability to inexpensively secure remote borders and other areas of interest. However, the presence of normal animal activity can often trigger a false alarm. Accurately detecting humans and distinguishing them from natural fauna is an important issue in security applications to reduce false alarm rates and improve the probability of detection. In particular, it is important to detect and classify people who are moving in remote locations and transmit back detections and analysis over extended periods at a low cost and with minimal maintenance. We developed and demonstrate a compact radar technology that is scalable to a variety of ultra-lightweight and low-power platforms for wide area persistent surveillance as an unattended, unmanned, and man-portable ground sensor. The radar uses micro-Doppler processing to characterize the tracks of moving targets and to then eliminate unimportant detections due to animals as well as characterize the activity of human detections. False alarms from sensors are a major liability that hinders widespread use. Incorporating rudimentary intelligence into sensors can reduce false alarms but can also result in a reduced probability of detection. Allowing an initial classification that can be updated with new observations and tracked over time provides a more robust framework for false alarm reduction at the cost of additional sensor observations. This paper explores these tradeoffs with a small radar sensor for border security. Multiple measurements were done to try to characterize the micro-Doppler of human versus animal and vehicular motion across a range of activities. Measurements were taken at the multiple sites with realistic but low levels of clutter. Animals move with a quadrupedal motion, which can be distinguished from the bipedal human motion. The micro-Doppler of a vehicle with rotating parts is also shown, along with ground truth images. Comparisons show large variations for

  1. Wireless sensor systems and methods, and methods of monitoring structures

    DOEpatents

    Kunerth, Dennis C.; Svoboda, John M.; Johnson, James T.; Harding, L. Dean; Klingler, Kerry M.

    2007-02-20

    A wireless sensor system includes a passive sensor apparatus configured to be embedded within a concrete structure to monitor infiltration of contaminants into the structure. The sensor apparatus includes charging circuitry and a plurality of sensors respectively configured to measure environmental parameters of the structure which include information related to the infiltration of contaminants into the structure. A reader apparatus is communicatively coupled to the sensor apparatus, the reader apparatus being configured to provide power to the charging circuitry during measurements of the environmental parameters by the sensors. The reader apparatus is configured to independently interrogate individual ones of the sensors to obtain information measured by the individual sensors. The reader apparatus is configured to generate an induction field to energize the sensor apparatus. Information measured by the sensor apparatus is transmitted to the reader apparatus via a response signal that is superimposed on a return induction field generated by the sensor apparatus. Methods of monitoring structural integrity of the structure are also provided.

  2. Nano- and micro-structured silicon for hybrid near-infrared photodetectors

    NASA Astrophysics Data System (ADS)

    Äńerek, V.; Głowacki, E. D.; Bednorz, M.; Demchyshyn, S.; Sariciftci, N. S.; Ivanda, M.

    2016-05-01

    Structuring surface and bulk of crystalline silicon on different length scales can significantly alter its properties and possibly improve the performance of opto-electronic devices and sensors based on silicon. Different dominant feature scales are responsible for modification of some of electronic and optical properties of silicon. Several easily reproducible chemical methods for facile structuring of silicon on nano and micro-scales, based on both electroless and anodic etching of silicon in hydrofluoric acid based etchants, and chemical anisotropic etching of silicon in basic environments, are presented. We show how successive micro and nano structuring creates hierarchical silicon surfaces, which can be used to simultaneously exploit the advantages of both structuring feature length scales. Finally, we demonstrate a large increase in photocurrent obtained from a hybrid structured silicon/organic near-infrared photodetector. Improved silicon/6,6'-dibromoindigo hybrid photodiodes were prepared by nano- and micro-structuring the silicon part of the heterojunction by wet chemical etching methods. Photocurrent and spectral responsivity were improved in comparison to planar diodes by up to two orders of magnitude by optimization of the silicon structuring process. We show that the improvement in photocurrent is not due to the increase in surface area or light trapping.

  3. Development of whispering gallery mode polymeric micro-optical electric field sensors.

    PubMed

    Ioppolo, Tindaro; Ötügen, Volkan; Ayaz, Ulas

    2013-01-01

    Optical modes of dielectric micro-cavities have received significant attention in recent years for their potential in a broad range of applications. The optical modes are frequently referred to as "whispering gallery modes" (WGM) or "morphology dependent resonances" (MDR) and exhibit high optical quality factors. Some proposed applications of micro-cavity optical resonators are in spectroscopy, micro-cavity laser technology, optical communications as well as sensor technology. The WGM-based sensor applications include those in biology, trace gas detection, and impurity detection in liquids. Mechanical sensors based on microsphere resonators have also been proposed, including those for force, pressure, acceleration and wall shear stress. In the present, we demonstrate a WGM-based electric field sensor, which builds on our previous studies. A candidate application of this sensor is in the detection of neuronal action potential. The electric field sensor is based on polymeric multi-layered dielectric microspheres. The external electric field induces surface and body forces on the spheres (electrostriction effect) leading to elastic deformation. This change in the morphology of the spheres, leads to shifts in the WGM. The electric field-induced WGM shifts are interrogated by exciting the optical modes of the spheres by laser light. Light from a distributed feedback (DFB) laser (nominal wavelength of ~ 1.3 μm) is side-coupled into the microspheres using a tapered section of a single mode optical fiber. The base material of the spheres is polydimethylsiloxane (PDMS). Three microsphere geometries are used: (1) PDMS sphere with a 60:1 volumetric ratio of base-to-curing agent mixture, (2) multi layer sphere with 60:1 PDMS core, in order to increase the dielectric constant of the sphere, a middle layer of 60:1 PDMS that is mixed with varying amounts (2% to 10% by volume) of barium titanate and an outer layer of 60:1 PDMS and (3) solid silica sphere coated with a thin layer

  4. A Diamond Electron Tunneling Micro-Electromechanical Sensor

    NASA Technical Reports Server (NTRS)

    Albin, Sacharia

    2000-01-01

    A new pressure sensing device using field emission from diamond coated silicon tips has been developed. A high electric field applied between a nano-tip array and a diaphragm configured as electrodes produces electron emission governed by the Fowler Nordheim equation. The electron emission is very sensitive to the separation between the diaphragm and the tips, which is fixed at an initial spacing and bonded such that a cavity is created between them. Pressure applied to the diaphragm decreases the spacing between the electrodes, thereby increasing the number of electrons emitted. Silicon has been used as a substrate on which arrays of diamond coated sharp tips have been fabricated for electron emission. Also, a diaphragm has been made using wet orientation dependent etching. These two structures were bonded together using epoxy and tested. Current - voltage measurements were made at varying pressures for 1-5 V biasing conditions. The sensitivity was found to be 2.13 mV/V/psi for a 20 x 20 array, which is comparable to that of silicon piezoresistive transducers. Thinner diaphragms as well as alternative methods of bonding are expected to improve the electrical characteristics of the device. This transducer will find applications in many engineering fields for pressure measurement.

  5. Optical fiber sensors for materials and structures characterization

    NASA Technical Reports Server (NTRS)

    Lindner, D. K.; Claus, R. O.

    1991-01-01

    The final technical report on Optical Fiber Sensors for Materials and Structures Characterization, covering the period August 1990 through August 1991 is presented. Research programs in the following technical areas are described; sapphire optical fiber sensors; vibration analysis using two-mode elliptical core fibers and sensors; extrinsic Fabry-Perot interferometer development; and coatings for fluorescent-based sensor. Research progress in each of these areas was substantial, as evidenced by the technical publications which are included as appendices.

  6. Technical standards for micro sensors in surgery and minimally invasive therapy.

    PubMed

    Neuder; Dehm

    2004-04-01

    The development of medical applications is fuelled in the context of steadily growing needs and the requirement of lowering overall costs. Micro systems will have an extremely important impact on medical technology in the future. The great challenges for the wider use of micro structures in health applications are biocompatibility and mass production. Especially small and medium-sized enterprises (SMEs) need help to overcome these problems by free access to knowledge, the availability of standards and contacts to partners.

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Real-time visualization of bridge structural response through wireless MEMS sensors

    NASA Astrophysics Data System (ADS)

    Chung, Hung-Chi; Enomoto, Tomoyuki; Loh, Kenneth; Shinozuka, Masanobu

    2004-07-01

    This study investigates the reliability and accuracy of wireless micro-electromechanical-system (MEMS)-type sensors in application of bridge structural vibration monitoring. With wireless capabilities added onto the developed sensors, it becomes unnecessary for engineers to connect enormous lengths of cables in order to measure vibration on bridges for instance. We investigated two types of MEMS accelerometers: the ADXL 202E and the Silicon Design 2210. To prove the validity of measuring acceleration by using these devices with wireless communication, we succeeded on measuring a pedestrian bridge's vibration under excitation loads in the center of span. The result had been compared with the traditional cabled sensor, PCB 393C. The wireless sensors were showed to be effective and much affordable to carry out the monitoring missions in situ.

  9. Magnetic Field Sensor Using Polymer MEMS Structures for Detection of Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Oldham, Bradley E.

    This thesis covers the development of a magnetic sensor for application with brain computer interfacing for the detection of motor imagery evoked potentials. For this application, the feasibility of a resonance magnetic cantilever based sensor is investigated via: numerical analysis for feasibility, multilayer structure for layer integration verification, and finally flexible magnetic material characterization for sensing element consideration. The flexible magnetic material that is considered in this thesis is made by the embedding of hard rare earth magnetic (Nd2Fe14B) particles into polydimethylsiloxane (PDMS) and provides a micro-mouldable material with hard magnetic properties. This material provides a couple advantages for design of a small magnetic sensor as it is scalable while being made of a rugged polymer. Additionally, this magnetic material exhibits magnetic rheological properties when exposed to a static magnetic field. While there is additional work needed to complete the sensor design, this thesis shows the feasibility of this design.

  10. Bio-inspired multi-mode optic flow sensors for micro air vehicles

    NASA Astrophysics Data System (ADS)

    Park, Seokjun; Choi, Jaehyuk; Cho, Jihyun; Yoon, Euisik

    2013-06-01

    Monitoring wide-field surrounding information is essential for vision-based autonomous navigation in micro-air-vehicles (MAV). Our image-cube (iCube) module, which consists of multiple sensors that are facing different angles in 3-D space, can be applied to the wide-field of view optic flows estimation (μ-Compound eyes) and to attitude control (μ- Ocelli) in the Micro Autonomous Systems and Technology (MAST) platforms. In this paper, we report an analog/digital (A/D) mixed-mode optic-flow sensor, which generates both optic flows and normal images in different modes for μ- Compound eyes and μ-Ocelli applications. The sensor employs a time-stamp based optic flow algorithm which is modified from the conventional EMD (Elementary Motion Detector) algorithm to give an optimum partitioning of hardware blocks in analog and digital domains as well as adequate allocation of pixel-level, column-parallel, and chip-level signal processing. Temporal filtering, which may require huge hardware resources if implemented in digital domain, is remained in a pixel-level analog processing unit. The rest of the blocks, including feature detection and timestamp latching, are implemented using digital circuits in a column-parallel processing unit. Finally, time-stamp information is decoded into velocity from look-up tables, multiplications, and simple subtraction circuits in a chip-level processing unit, thus significantly reducing core digital processing power consumption. In the normal image mode, the sensor generates 8-b digital images using single slope ADCs in the column unit. In the optic flow mode, the sensor estimates 8-b 1-D optic flows from the integrated mixed-mode algorithm core and 2-D optic flows with an external timestamp processing, respectively.

  11. The development of micro/nano chemical sensor systems for aerospace applications

    NASA Astrophysics Data System (ADS)

    Hunter, G. W.; Xu, J. C.; Evans, L.; Biaggi-Labiosa, A.; Ward, B. J.; Rowe, S.; Makel, D. B.; Liu, C. C.; Dutta, P.; Berger, G. M.; Vander Wal, R. L.

    2010-04-01

    Aerospace applications require a range of chemical sensing technologies to monitor conditions related to both space exploration and aeronautic aircraft operations. These applications include leak detection, engine emissions monitoring, fire detection, human health monitoring, and environmental monitoring. This paper discusses efforts to produce microsensor platforms and Smart Sensor Systems that can be tailored to measure a range of chemical species. This technology development ranges from development of base sensor platforms to the evaluation of more mature systems in relevant environments. Although microsensor systems can have a significant impact on aerospace applications, extensive application testing is necessary for their long-term implementation. The introduction of nanomaterials into microsensor platforms has the potential to significantly enable improved sensor performance, but control of those nanostructures is necessary in order to achieve maximum benefits. Examples will be given of microsensor platform technology, Smart Sensor Systems, application testing, and efforts to integrate and control nanostructures into sensor structures.

  12. Xenon Additives Detection in Helium Micro-Plasma Gas Analytical Sensor

    NASA Astrophysics Data System (ADS)

    Tsyganov, Alexander; Kudryavtsev, Anatoliy; Mustafaev, Alexander

    2012-10-01

    Electron energy spectra of Xe atoms at He filled micro-plasma afterglow gas analyzer were observed using Collisional Electron Spectroscopy (CES) method [1]. According to CES, diffusion path confinement for characteristic electrons makes it possible to measure electrons energy distribution function (EEDF) at a high (up to atmospheric) gas pressure. Simple geometry micro-plasma CES sensor consists of two plane parallel electrodes detector and microprocessor-based acquisition system providing current-voltage curve measurement in the afterglow of the plasma discharge. Electron energy spectra are deduced as 2-nd derivative of the measured current-voltage curve to select characteristic peaks of the species to be detected. Said derivatives were obtained by the smoothing-differentiating procedure using spline least-squares approximation of a current-voltage curve. Experimental results on CES electron energy spectra at 10-40 Torr in pure He and in admixture with 0.3% Xe are discussed. It demonstrates a prototype of the new miniature micro-plasma sensors for industry, safety and healthcare applications. [1]. A.A.Kudryavtsev, A.B.Tsyganov. US Patent 7,309,992. Gas analysis method and ionization detector for carrying out said method, issued December 18, 2007.

  13. Formation of micro/nano structures out of soap bubbles

    NASA Astrophysics Data System (ADS)

    Bai, Xiao-Dan; Liu, Jing

    2007-07-01

    We proposed to synthesize, etch and construct micro/nano structures through manipulating the large-scale bubbles composed of specific chemical compounds. The core of the method lies in the chemical reaction occurred at the interfaces between two or more soap bubbles. A unique virtue of the bubble is that it can have a rather large diameter however an extremely small membrane thickness, whose smallest size could reach nano scale. Therefore, the chemical reaction and synthesis occurred in the common interface of such contacting bubbles would lead to products with very small size. Several typical micro structures were fabricated to demonstrate the feasibility of the new method. Being flexible, easily controllable and environment friendly, the present concept may open a straightforward low-cost way for making micro/nano structures.

  14. Motion compensation for structured light sensors

    NASA Astrophysics Data System (ADS)

    Biswas, Debjani; Mertz, Christoph

    2015-05-01

    In order for structured light methods to work outside, the strong background from the sun needs to be suppressed. This can be done with bandpass filters, fast shutters, and background subtraction. In general this last method necessitates the sensor system to be stationary during data taking. The contribution of this paper is a method to compensate for the motion if the system is moving. The key idea is to use video stabilization techniques that work even if the illuminator is switched on and off from one frame to another. We used OpenCV functions and modules to implement a robust and efficient method. We evaluated it under various conditions and tested it on a moving robot outdoors. We will demonstrate that one can not only do 3D reconstruction under strong ambient light, but that it is also possible to observe optical properties of the objects in the environment.

  15. Applicability of New Approaches of Sensor Orientation to Micro Aerial Vehicles

    NASA Astrophysics Data System (ADS)

    Rehak, M.; Skaloud, J.

    2016-06-01

    This study highlights the benefits of precise aerial position and attitude control in the context of mapping with Micro Aerial Vehicles (MAVs). Accurate mapping with MAVs is gaining importance in applications such as corridor mapping, road and pipeline inspections or mapping of large areas with homogeneous surface structure, e.g. forests or agricultural fields. There, accurate aerial control plays a major role in successful terrain reconstruction and artifact-free ortophoto generation. The presented experiments focus on new approaches of aerial control. We confirm practically that the relative aerial position and attitude control can improve accuracy in difficult mapping scenarios. Indeed, the relative orientation method represents an attractive alternative in the context of MAVs for two reasons. First, the procedure is somewhat simplified, e.g. the angular misalignment, so called boresight, between the camera and the inertial measurement unit (IMU) does not have to be determined and, second, the effect of possible systematic errors in satellite positioning (e.g. due to multipath and/or incorrect recovery of differential carrier-phase ambiguities) is mitigated. First, we present a typical mapping project over an agricultural field and second, we perform a corridor road mapping. We evaluate the proposed methods in scenarios with and without automated image observations. We investigate a recently proposed concept where adjustment is performed using image observations limited to ground control and check points, so called fast aerial triangulation (Fast AT). In this context we show that accurate aerial control (absolute or relative) together with a few image observations can deliver accurate results comparable to classical aerial triangulation with thousands of image measurements. This procedure in turns reduces the demands on processing time and the requirements on the existence of surface texture. Finally, we compare the above mentioned procedures with direct sensor

  16. Magnetic Micro/Nano Structures for Biological Manipulation

    NASA Astrophysics Data System (ADS)

    Huang, Chen-Yu; Hsieh, Teng-Fu; Chang, Wei-Chieh; Yeh, Kun-Chieh; Hsu, Ming-Shinn; Chang, Ching-Ray; Chen, Jiann-Yeu; Wei, Zung-Hang

    2016-05-01

    Biomanipulation based on micro/nano structures is an attractive approach for biotechnology. To manipulate biological systems by magnetic forces, the magnetic labeling technology utilized magnetic nanoparticles (MNPs) as a common rule. Ferrofluid, well-dispersed MNPs, can be used for magnetic modification of the surface or as molds to form organized microstructures. For magnetic-based micro/nano structures, different methods to modulate magnetic field at the microscale have been developed. Specifically, this review focused on a new strategy which uses the concept of micromagnetism of patterned magnetic thin film with specific domain walls configurations to generate stable magnetic poles for cell patterning.

  17. Magnetic Micro/Nano Structures for Biological Manipulation

    NASA Astrophysics Data System (ADS)

    Huang, Chen-Yu; Hsieh, Teng-Fu; Chang, Wei-Chieh; Yeh, Kun-Chieh; Hsu, Ming-Shinn; Chang, Ching-Ray; Chen, Jiann-Yeu; Wei, Zung-Hang

    2016-05-01

    Biomanipulation based on micro/nano structures is an attractive approach for biotechnology. To manipulate biological systems by magnetic forces, the magnetic labeling technology utilized magnetic nanoparticles (MNPs) as a common rule. Ferrofluid, well-dispersed MNPs, can be used for magnetic modification of the surface or as molds to form organized microstructures. For magnetic-based micro/nano structures, different methods to modulate magnetic field at the microscale have been developed. Specifically, this review focused on a new strategy which uses the concept of micromagnetism of patterned magnetic thin film with specific domain walls configurations to generate stable magnetic poles for cell patterning.

  18. Local structure of ZnO micro flowers and nanoparticles obtained by micro segmented flow synthesis

    SciTech Connect

    Li, Shuning; Roy, Amitava; Lichtenberg, Henning; Merchan, Gregory; Kumar, Challa S.S.R.; Köhler, J. Michael

    2012-03-07

    The micro-segmented flow technique was applied for continuous synthesis of ZnO micro- and nanoparticles with short residence times of 9.4 s and 21.4 s, respectively. The obtained particles were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Small angle X-ray scattering (SAXS) and photoluminescence spectroscopy were used to determine the size and optical properties of ZnO nanoparticles. In addition, extended X-ray absorption fine structure (EXAFS) spectroscopy was employed to investigate local structural properties. The EXAFS measurements reveal a larger degree of structural disorder in the nanoparticles than the microparticles. These structural changes should be taken into consideration while evaluating the size-dependent visible emission of ZnO nanoparticles.

  19. A comparative study of MOEM pressure sensors using MZI, DC, and racetrack resonator IO structures

    NASA Astrophysics Data System (ADS)

    Selvarajan, A.; Pattnaik, Prasant Kumar; Badrinarayana, T.; Srinivas, T.

    2006-03-01

    In recent years micro-electro-mechanical system (MEMS) sensors have drawn considerable attention due to their attraction in terms of miniaturization, batch fabrication and ease of integration with the required electronics circuitry. Micro-opto-electro-mechanical (MOEM) devices and systems, based on the principles of integrated optics and micromachining technology on silicon have immense potential for sensor applications. Employing optical techniques have important advantages such as functionality, large bandwidth and higher sensitivity. Pressure sensing is currently the most lucrative market for solid-state micro sensors. Pressure sensing using micromachined structures utilize the changes induced in either the resistive or capacitive properties of the electro-mechanical structure by the impressed pressure. Integrated optical pressure sensors can utilize the changes to the amplitude, phase, refractive index profile, optical path length, or polarization of the lightwave by the external pressure. In this paper we compare the performance characteristics of three types of MOEM pressure sensors based on Mach-Zehnder Interferometer (MZI), Directional Coupler (DC) and racetrack resonator (RR) integrated optical geometries. The first two configurations measure the pressure changes through a change in optical intensity while the third one measures the same in terms of frequency or wavelength change. The analysis of each sensors has been carried out in terms of mechanical and optical models and their interrelationship through optomechanical coupling. For a typical diaphragm of size 2mm × 1mm × 20 μm, normalized pressure sensitivity of 18.35 μW/mW/kPa, 29.37 μW/mW/kPa and 2.26 pm/kPa in case of MZI, DC and RR devices have been obtained respectively. The noise performance of these devices are also presented.

  20. Ab initio structure determination from prion nanocrystals at atomic resolution by MicroED

    PubMed Central

    Sawaya, Michael R.; Rodriguez, Jose; Cascio, Duilio; Collazo, Michael J.; Shi, Dan; Reyes, Francis E.; Gonen, Tamir; Eisenberg, David S.

    2016-01-01

    Electrons, because of their strong interaction with matter, produce high-resolution diffraction patterns from tiny 3D crystals only a few hundred nanometers thick in a frozen-hydrated state. This discovery offers the prospect of facile structure determination of complex biological macromolecules, which cannot be coaxed to form crystals large enough for conventional crystallography or cannot easily be produced in sufficient quantities. Two potential obstacles stand in the way. The first is a phenomenon known as dynamical scattering, in which multiple scattering events scramble the recorded electron diffraction intensities so that they are no longer informative of the crystallized molecule. The second obstacle is the lack of a proven means of de novo phase determination, as is required if the molecule crystallized is insufficiently similar to one that has been previously determined. We show with four structures of the amyloid core of the Sup35 prion protein that, if the diffraction resolution is high enough, sufficiently accurate phases can be obtained by direct methods with the cryo-EM method microelectron diffraction (MicroED), just as in X-ray diffraction. The success of these four experiments dispels the concern that dynamical scattering is an obstacle to ab initio phasing by MicroED and suggests that structures of novel macromolecules can also be determined by direct methods. PMID:27647903

  1. High-finesse micro-lens fiber-optic extrinsic Fabry Perot interferometric sensors

    NASA Astrophysics Data System (ADS)

    Jiang, Yi; Tang, Caijie

    2008-10-01

    Micro-lenses are produced on two mirror-coated fiber ends in an extrinsic Fabry-Perot interferometer (EFPI) by curing epoxy droplets to obtain a high-finesse resonator. The high-finesse resonator is easy to construct, and can be used as a highly sensitive sensor at a low cost. The experimental results show that a temperature resolution of 0.025 °C and a strain resolution of 0.0625 µɛ can be achieved with such an EFPI.

  2. Considerations in the design and sensitivity optimization of the micro tactile sensor.

    PubMed

    Murayama, Yoshinobu; Omata, Sadao

    2005-03-01

    Although miniaturization has been considered the only technology with which to increase sensitivity of tactile sensors, we recently developed the micro tactile sensor (MTS) that performs with high sensitivity without microfabrication. In this study, we examined design and sensitivity optimization of the MTS using theory based upon Mason's equivalent circuit. The touch probe, which is attached to the lead zirconate titanate (PZT) element, was expressed as a purely inductive circuit component. Resonance frequency was calculated as a function of the length of the touch probe, and sensitivity was predicted to be dependent on the length. Furthermore, many kinds of MTS were fabricated with different touch probe lengths, and actual sensitivity was measured as phase shift between nonloaded and loaded conditions. And, from the consideration of theory and experimental data, a sensitivity coefficient was proposed and found to be useful.

  3. Radio telemetry interrogation of multiple fiber sensors in civil structures

    NASA Astrophysics Data System (ADS)

    Fuhr, Peter L.; Huston, Dryver R.; Ambrose, Timothy P.

    1993-03-01

    We have examined various fiber sensor multiplexing techniques, e.g., frequency-, time-, coherence-multiplexing, in an attempt to ascertain the method best suited for interrogation of multiple sensors scattered throughout a modern civil structure. Based on our embedded fiber sensor results conducted at the Stafford Biotechnology Complex at the University of Vermont, a 65,000 square foot, multistory reinforced concrete structure, where more than fifty single- mode and multimode fiber optic sensors have been embedded into the structure, we have determined that in many instances a radio telemetry method of interrogating the sensors is optimal. Many real-world factors such as architectural details, lighting, power, and HVAC design requirements influence the overall nature of the use of multiplexed fiber sensors in civil structures. In instances where we have multiplexed intensity-modulating fiber sensors onto a single transmit/receive fiber, radio telemeterized command and data acquisition from the fiber sensor `network' may be achieved. The development of the interrogation of the multiplexed fiber optic sensors is presented, as are experimental results obtained from fiber optic vibration sensors.

  4. Test Structures Applied to the Rapid Prototyping of Sensors

    NASA Technical Reports Server (NTRS)

    Buehler, M.; Chang, L-J.; Martin, D.

    1997-01-01

    Recently, test structures were used to aid in the rapid development of a gas sensor and pressure sensor. These sensors were fabricated using co-fired ceramic technology and a multiproject approach. This talk will describe results obtained from a ceramic substrate which contained 36 chips with six variants including the sensors, process control monitors, and an interconnect chip. As far as the authors know, this is the first implementation of multi-projects in co-fired ceramic substrate. The gas sensor is being developed for the Space Shuttle and the pressure gage is being developed as a Martian barometer.

  5. Structural Health Monitoring Sensor Development at NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Prosser, W. H.; Wu, M. C.; Allison, S. G.; DeHaven, S. L.; Ghoshal, A.

    2002-01-01

    NASA is applying considerable effort on the development of sensor technology for structural health monitoring (SHM). This research is targeted toward increasing the safety and reliability of aerospace vehicles, while reducing operating and maintenance costs. Research programs are focused on applications to both aircraft and space vehicles. Sensor technologies under development span a wide range including fiber-optic sensing, active and passive acoustic sensors, electromagnetic sensors, wireless sensing systems, MEMS, and nanosensors. Because of their numerous advantages for aerospace applications, fiber-optic sensors are one of the leading candidates and are the major focus of this presentation. In addition, recent advances in active and passive acoustic sensing will also be discussed.

  6. Development of a thick film PZT foil sensor for use in structural health monitoring applications.

    PubMed

    Pickwell, Andrew J; Dorey, Robert A; Mba, David

    2013-02-01

    Acoustic emission (AE) monitoring is a technique of growing interest in the field of nondestructive testing (NDT). The use of AE devices to monitor the health of structural components is currently limited by the cost of AE equipment, which prohibits the permanent placement of AE devices on structures for the purposes of continuous monitoring and the monitoring of areas with limited access. Micro electromechanical systems (MEMS) can provide solutions to these problems. We present the manufacture of a 4.4-μm-thick lead zirconate titanate (PZT) film on a 110-μm-thick titanium foil substrate for use as an AE sensor. The thick-film sensor is benchmarked against commercially available AE sensors in static and dynamic monitoring applications. The thick-film AE device is found to perform well in the detection of AE in static applications. A low signal-to-noise ratio is found to prohibit the detection of AE in a dynamic application.

  7. An Intrinsic Fiber-Optic Single Loop Micro-Displacement Sensor

    PubMed Central

    Martinez-Rios, Alejandro; Monzon-Hernandez, David; Torres-Gomez, Ismael; Salceda-Delgado, Guillermo

    2012-01-01

    A micro-displacement sensor consisting of a fiber-loop made with a tapered fiber is reported. The sensor operation is based on the interaction between the fundamental cladding mode propagating through the taper waist and higher order cladding modes excited when the taper is deformed to form a loop. As a result, a transmission spectrum with several notches is observed, where the notch wavelength resonances shift as a function of the loop diameter. The loop diameter is varied by the spatial displacement of one end of the fiber-loop attached to a linear translation stage. In a displacement range of 3.125 mm the maximum wavelength shift is 360.93 nm, with 0.116 nm/μm sensitivity. By using a 1,280 nm broadband low-power LED source and a single Ge-photodetector in a power transmission sensor setup, a sensitivity in the order of 2.7 nW/μm is obtained in ∼1 mm range. The proposed sensor is easy to implement and has a plenty of room to improve its performance. PMID:22368477

  8. A quartz-based micro catalytic methane sensor by high resolution screen printing

    NASA Astrophysics Data System (ADS)

    Lu, Wenshuai; Jing, Gaoshan; Bian, Xiaomeng; Yu, Hongyan; Cui, Tianhong

    2016-02-01

    A micro catalytic methane sensor was proposed and fabricated on a bulk fused quartz substrate using a high resolution screen printing technique for the first time, with reduced power consumption and optimized sensitivity. The sensor was designed by the finite element method and quartz was chosen as the substrate material and alumina support with optimized dimensions. Fabrication of the sensor consisted of two MEMS processes, lift-off and high resolution screen printing, with the advantages of high yield and uniformity. When the sensor’s regional working temperature changes from 250 °C to 470 °C, its sensitivity increases, as well as the power consumption. The highest sensitivity can reach 1.52 mV/% CH4. A temperature of 300 °C was chosen as the optimized working temperature, and the sensor’s sensitivity, power consumption, nonlinearity and response time are 0.77 mV/% CH4, 415 mW, 2.6%, and 35 s, respectively. This simple, but highly uniform fabrication process and the reliable performance of this sensor may lead to wide applications for methane detection.

  9. Metrology and characterization of impurity transport during cleaning of micro and nano structures

    NASA Astrophysics Data System (ADS)

    Yan, Jun

    A major challenge in the manufacturing of micro and nano devices is the cleaning, rinsing, and drying of very small structures. Without a technology for in situ and real-time monitoring and controlling, the rinse processes that account for a significant fraction of the total processing steps use a large amount of water and energy perhaps unnecessarily. This "blind" processing approach leads to waste that can have significant economic and environmental impacts. An electrochemical residue sensor (ECRS) has been developed and is aimed at in situ and real-time measurement of residual contamination inside the micro and nano structures. Using this technology, the mechanisms and bottlenecks of cleaning, rinsing, and drying can be investigated and the processes can be monitored and controlled. An equivalent circuit model was developed to assist the design of the sensor; its validity was proved by the first prototype. The simulation results and the experimental data predicted a good sensitivity in a wide range of operational frequency. To use the sensor in a practical rinse tank setup, the sensor-on-wafer prototype was designed and fabricated. Both the fab-scale and the lab-scale tests were performed and results illustrated many successes. The sensor is the first and the only available technology that provides the in situ and real-time cleanness information in the microstructures during the rinse processes. The sensor results distinguished four different types of rinse processes and showed high sensitivity to the ionic concentration change in the microstructures. The impacts of cleaning and rinsing parameters such as flow rate, temperature, cleaning solution concentrations, and process time on the sulfuric acid rinsing efficiency were investigated by using the sensor. The investigation discovered that sulfuric acid rinsing is a two-stage process: a flow-control stage and a desorption-control stage. A comprehensive rinse model was developed to correlate the transport process

  10. In situ synthesis of porous array films on a filament induced micro-gap electrode pair and their use as resistance-type gas sensors with enhanced performances.

    PubMed

    Xu, Zongke; Duan, Guotao; Zhang, Hongwen; Wang, Yingying; Xu, Lei; Cai, Weiping

    2015-09-14

    Resistance-type metal-oxide semiconductor gas sensors with high sensitivity and low detection limit have been explored for practical applications. They require both sensing films with high sensitivity to target gases and an appropriate structure of the electrode-equipped substrate to support the sensing films, which is still challenging. In this paper, a new gas sensor of metal-oxide porous array films on a micro-gap electrode pair is designed and implemented by taking ZnO as a model material. First, a micro-gap electrode pair was constructed by sputtering deposition on a filament template, which was used as the sensor's supporting substrate. Then, the sensing film, made up of ZnO porous periodic arrays, was in situ synthesized onto the supporting substrate by a solution-dipping colloidal lithography strategy. The results demonstrated the validity of the strategy, and the as-designed sensor shows a small device-resistance, an enhanced sensing performance with high resolution and an ultralow detection limit. This work provides an alternative method to promote the practical application of resistance-type gas sensors.

  11. Fabrication of micro-nano structure nanofibers by solvent etching.

    PubMed

    Min, Minghua; Wang, Xuefen; Yang, Yin; Liu, Zongyuan; Zhou, Zhe; Zhu, Meifang; Chen, Yanmo; Hsiao, Benjamin S

    2011-08-01

    Micro-Nano structure nanofibrous affinity membranes of poly(ether sulfones) (PES) blended with a functional polymer poly(ethyleneimine) (PEI) were fabricated by electrospinning technique followed by solvent etching in crosslinking solution. The surface SEM image of the water washed PES/PEI nanofibrous membrane confirmed that PEI was concentrated on the fiber surface. The nanofibrous PES/PEI membranes were crosslinked in a mixture of acetone and water with glutaraldehyde (crosslinking agent, GA), and the micro-nano structural surface of the nanofibrous membranes was created by solvent etching due to the solvation between PEI and the solvent water in the crosslinking solution during the crosslinking process. The influence of the component of the crosslinking bath on the mophology of the resulting PES/PEI nanofibers was investigated. It was found that the relatively uniform micro-nano spherules grew on the surface of the nanofibers when the content of water in crosslinking solution was more than 20 wt%, and the diameters of the spherules were in the range of 50-250 nm. The advantage of the micro-nano structrue for the heavy metal ions removal in wastwater has been demonstrated by taking a series of static adsorption experiments. It was found that the micro-nano structrue of PES/PEI nanofibrous membranes could bring high performance of adsorption capacity for heavy metal ions, indicating that the unique morphology could bring much more large surface area per unit mass and high effectivity for heavy metal ions removal from aqueous solutions.

  12. Aircraft Aerodynamic Parameter Detection Using Micro Hot-Film Flow Sensor Array and BP Neural Network Identification

    PubMed Central

    Que, Ruiyi; Zhu, Rong

    2012-01-01

    Air speed, angle of sideslip and angle of attack are fundamental aerodynamic parameters for controlling most aircraft. For small aircraft for which conventional detecting devices are too bulky and heavy to be utilized, a novel and practical methodology by which the aerodynamic parameters are inferred using a micro hot-film flow sensor array mounted on the surface of the wing is proposed. A back-propagation neural network is used to model the coupling relationship between readings of the sensor array and aerodynamic parameters. Two different sensor arrangements are tested in wind tunnel experiments and dependence of the system performance on the sensor arrangement is analyzed. PMID:23112638

  13. Micro-machined thin film hydrogen gas sensor, and method of making and using the same

    NASA Technical Reports Server (NTRS)

    DiMeo, Jr., Frank (Inventor); Bhandari, Gautam (Inventor)

    2001-01-01

    A hydrogen sensor including a thin film sensor element formed, e.g., by metalorganic chemical vapor deposition (MOCVD) or physical vapor deposition (PVD), on a microhotplate structure. The thin film sensor element includes a film of a hydrogen-interactive metal film that reversibly interacts with hydrogen to provide a correspondingly altered response characteristic, such as optical transmissivity, electrical conductance, electrical resistance, electrical capacitance, magnetoresistance, photoconductivity, etc., relative to the response characteristic of the film in the absence of hydrogen. The hydrogen-interactive metal film may be overcoated with a thin film hydrogen-permeable barrier layer to protect the hydrogen-interactive film from deleterious interaction with non-hydrogen species. The hydrogen sensor of the invention may be usefully employed for the detection of hydrogen in an environment susceptible to the incursion or generation of hydrogen and may be conveniently configured as a hand-held apparatus.

  14. Software structure for broadband wireless sensor network system

    NASA Astrophysics Data System (ADS)

    Kwon, Hyeokjun; Oh, Sechang; Yoon, Hargsoon; Varadan, Vijay K.

    2010-04-01

    Zigbee Sensor Network system has been investigating for monitoring and analyzing the data measured from a lot of sensors because the Zigbee Sensor Network has several advantages of low power consumption, compact size, and multi-node connection. However, it has a disadvantage not to be able to monitor the data measured from sensors at the remote area such as other room that is located at other city. This paper describes the software structure to compensate the defect with combining the Zigbee Sensor Network and wireless LAN technology for remote monitoring of measured sensor data. The software structure has both benefits of Zigbee Sensor Network and the advantage of wireless LAN. The software structure has three main software structures. The first software structure consists of the function in order to acquire the data from sensors and the second software structure is to gather the sensor data through wireless Zigbee and to send the data to Monitoring system by using wireless LAN. The second part consists of Linux packages software based on 2440 CPU (Samsung corp.), which has ARM9 core. The Linux packages include bootloader, device drivers, kernel, and applications, and the applications are TCP/IP server program, the program interfacing with Zigbee RF module, and wireless LAN program. The last part of software structure is to receive the sensor data through TCP/IP client program from Wireless Gate Unit and to display graphically measured data by using MATLAB program; the sensor data is measured on 100Hz sampling rate and the measured data has 10bit data resolution. The wireless data transmission rate per each channel is 1.6kbps.

  15. Distributed adaptive diagnosis of sensor faults using structural response data

    NASA Astrophysics Data System (ADS)

    Dragos, Kosmas; Smarsly, Kay

    2016-10-01

    The reliability and consistency of wireless structural health monitoring (SHM) systems can be compromised by sensor faults, leading to miscalibrations, corrupted data, or even data loss. Several research approaches towards fault diagnosis, referred to as ‘analytical redundancy’, have been proposed that analyze the correlations between different sensor outputs. In wireless SHM, most analytical redundancy approaches require centralized data storage on a server for data analysis, while other approaches exploit the on-board computing capabilities of wireless sensor nodes, analyzing the raw sensor data directly on board. However, using raw sensor data poses an operational constraint due to the limited power resources of wireless sensor nodes. In this paper, a new distributed autonomous approach towards sensor fault diagnosis based on processed structural response data is presented. The inherent correlations among Fourier amplitudes of acceleration response data, at peaks corresponding to the eigenfrequencies of the structure, are used for diagnosis of abnormal sensor outputs at a given structural condition. Representing an entirely data-driven analytical redundancy approach that does not require any a priori knowledge of the monitored structure or of the SHM system, artificial neural networks (ANN) are embedded into the sensor nodes enabling cooperative fault diagnosis in a fully decentralized manner. The distributed analytical redundancy approach is implemented into a wireless SHM system and validated in laboratory experiments, demonstrating the ability of wireless sensor nodes to self-diagnose sensor faults accurately and efficiently with minimal data traffic. Besides enabling distributed autonomous fault diagnosis, the embedded ANNs are able to adapt to the actual condition of the structure, thus ensuring accurate and efficient fault diagnosis even in case of structural changes.

  16. Flow Type Bio-Chemical Calorimeter with Micro Differential Thermopile Sensor.

    PubMed

    Saito, Masataka; Nakabeppu, Osamu

    2015-04-01

    Bio-chemical calorimeters with a MEMS (Micro-Electro-Mechanical Systems) thermopile sensor have been studied for monitoring detailed processes of the biochemical reactions of a minute sample with a high temporal resolution. The bio-calorimeters are generally divided into a batch-type and a flow-type. We developed a highly sensitive batch-type calorimeter which can detect a 100 nW level thermal reaction. However it shows a long settling time of 2 hours because of the heat capacity of a whole calorimeter. Thus, the flow-type calorimeters in passive and active mode have been studied for measuring the thermal reactions in an early stage after starting an analysis. The flow-type calorimeter consists of the MEMS differential thermopile sensor, a pair of micro channel reactor in a PDMS (polydimethylsiloxane) sheet in a three-fold thermostat chamber. The calorimeter in the passive mode was tested with dilution reactions of ethanol to water and NaCl aqueous solution to water. It was shown that the calorimeter detects exo- and endothermic reaction over 250 nW at solution flow rate of 0.05 ~ 1 µl/min with a settling time of about 4 minutes. In the active mode, a response test was conducted by using heat removal by water flow from the reactor channel. The active calorimetry enhances the response time about three to four times faster. PMID:26353514

  17. Flow Type Bio-Chemical Calorimeter with Micro Differential Thermopile Sensor.

    PubMed

    Saito, Masataka; Nakabeppu, Osamu

    2015-04-01

    Bio-chemical calorimeters with a MEMS (Micro-Electro-Mechanical Systems) thermopile sensor have been studied for monitoring detailed processes of the biochemical reactions of a minute sample with a high temporal resolution. The bio-calorimeters are generally divided into a batch-type and a flow-type. We developed a highly sensitive batch-type calorimeter which can detect a 100 nW level thermal reaction. However it shows a long settling time of 2 hours because of the heat capacity of a whole calorimeter. Thus, the flow-type calorimeters in passive and active mode have been studied for measuring the thermal reactions in an early stage after starting an analysis. The flow-type calorimeter consists of the MEMS differential thermopile sensor, a pair of micro channel reactor in a PDMS (polydimethylsiloxane) sheet in a three-fold thermostat chamber. The calorimeter in the passive mode was tested with dilution reactions of ethanol to water and NaCl aqueous solution to water. It was shown that the calorimeter detects exo- and endothermic reaction over 250 nW at solution flow rate of 0.05 ~ 1 µl/min with a settling time of about 4 minutes. In the active mode, a response test was conducted by using heat removal by water flow from the reactor channel. The active calorimetry enhances the response time about three to four times faster.

  18. Porous Si structure as moisture sensor

    SciTech Connect

    Peterson, D.W.; Nguyen, L.T.

    1996-12-31

    Development and characterization of a capacitive moisture sensor made from porous Si is presented. The sensor development was in support of the DoD funded Plastic Package Availability program and was intended for the detection of pinholes and defects in moisture barrier coatings applied to ICs during fabrication or during the plastic encapsulation assembly process.

  19. Nanometer resolution self-powered static and dynamic motion sensor based on micro-grated triboelectrification.

    PubMed

    Zhou, Yu Sheng; Zhu, Guang; Niu, Simiao; Liu, Ying; Bai, Peng; Jing, Qingsheng; Wang, Zhong Lin

    2014-03-19

    A one-dimensional displacement and speed sensing technology that consists of a pair of micro-grating structures and utilizes the coupling between the triboelectric effect and electrostatic induction is demonstrated. Its distinct advantages, including being self-powered, high resolution, large dynamic range, and long detecting distance, show extensive potential applications in automation, manufacturing, process control, and portable devices.

  20. Micro-structured surfaces for algal biofilm growth

    NASA Astrophysics Data System (ADS)

    Sathananthan, Suthamathy; Genin, Scott N.; Aitchison, J. Stewart; Allen, D. Grant

    2013-12-01

    It is well known that cells respond to structured surface cues that are on the micro/nanometer scale. Tissue engineering and bio-fouling fields have utilized the semiconductor device fabrication processes to make micro- and nanometer patterned surfaces to study animal cell tissue formation and to prevent algae attachment on marine surfaces respectively. In this paper we describe the use of micro-structured surfaces to study the attachment and growth of algal films. This paper gives an overview of how micro-structured surfaces are made for this purpose, how they are incorporated into a photo bioreactor and how this patterning influences the growth of an algal biofilm. Our results suggest that surface patterning with deeper V-groove patterns that are of the same size scale as the algal species has resulted in higher biomass productivity giving them a chance to embed and attach on the slope and flat surfaces whereas shallower size grooves and completely flat surfaces did not show this trend.

  1. A Multi-Phase Based Fluid-Structure-Microfluidic interaction sensor for Aerodynamic Shear Stress

    NASA Astrophysics Data System (ADS)

    Hughes, Christopher; Dutta, Diganta; Bashirzadeh, Yashar; Ahmed, Kareem; Qian, Shizhi

    2014-11-01

    A novel innovative microfluidic shear stress sensor is developed for measuring shear stress through multi-phase fluid-structure-microfluidic interaction. The device is composed of a microfluidic cavity filled with an electrolyte liquid. Inside the cavity, two electrodes make electrochemical velocimetry measurements of the induced convection. The cavity is sealed with a flexible superhydrophobic membrane. The membrane will dynamically stretch and flex as a result of direct shear cross-flow interaction with the seal structure, forming instability wave modes and inducing fluid motion within the microfluidic cavity. The shear stress on the membrane is measured by sensing the induced convection generated by membrane deflections. The advantages of the sensor over current MEMS based shear stress sensor technology are: a simplified design with no moving parts, optimum relationship between size and sensitivity, no gaps such as those created by micromachining sensors in MEMS processes. We present the findings of a feasibility study of the proposed sensor including wind-tunnel tests, microPIV measurements, electrochemical velocimetry, and simulation data results. The study investigates the sensor in the supersonic and subsonic flow regimes. Supported by a NASA SBIR phase 1 contract.

  2. Bidirectional Promoter Engineering for Single Cell MicroRNA Sensors in Embryonic Stem Cells

    PubMed Central

    Sladitschek, Hanna L.

    2016-01-01

    MicroRNAs have emerged as important markers and regulators of cell identity. Precise measurements of cellular miRNA levels rely traditionally on RNA extraction and thus do not allow to follow miRNA expression dynamics at the level of single cells. Non-invasive miRNA sensors present an ideal solution but they critically depend on the performance of suitable ubiquitous promoters that reliably drive expression both in pluripotent and differentiated cell types. Here we describe the engineering of bidirectional promoters that drive the expression of precise ratiometric fluorescent miRNA sensors in single mouse embryonic stem cells (mESCs) and their differentiated derivatives. These promoters are based on combinations of the widely used CAG, EF1α and PGK promoters as well as the CMV and PGK enhancers. miR-142-3p, which is known to be bimodally expressed in mESCs, served as a model miRNA to gauge the precision of the sensors. The performance of the resulting miRNA sensors was assessed by flow cytometry in single stable transgenic mESCs undergoing self-renewal or differentiation. EF1α promoters arranged back-to-back failed to drive the robustly correlated expression of two transgenes. Back-to-back PGK promoters were shut down during mESC differentiation. However, we found that a back-to-back arrangement of CAG promoters with four CMV enhancers provided both robust expression in mESCs undergoing differentiation and the best signal-to-noise for measurement of miRNA activity in single cells among all the sensors we tested. Such a bidirectional promoter is therefore particularly well suited to study the dynamics of miRNA expression during cell fate transitions at the single cell level. PMID:27152616

  3. Bidirectional Promoter Engineering for Single Cell MicroRNA Sensors in Embryonic Stem Cells.

    PubMed

    Sladitschek, Hanna L; Neveu, Pierre A

    2016-01-01

    MicroRNAs have emerged as important markers and regulators of cell identity. Precise measurements of cellular miRNA levels rely traditionally on RNA extraction and thus do not allow to follow miRNA expression dynamics at the level of single cells. Non-invasive miRNA sensors present an ideal solution but they critically depend on the performance of suitable ubiquitous promoters that reliably drive expression both in pluripotent and differentiated cell types. Here we describe the engineering of bidirectional promoters that drive the expression of precise ratiometric fluorescent miRNA sensors in single mouse embryonic stem cells (mESCs) and their differentiated derivatives. These promoters are based on combinations of the widely used CAG, EF1α and PGK promoters as well as the CMV and PGK enhancers. miR-142-3p, which is known to be bimodally expressed in mESCs, served as a model miRNA to gauge the precision of the sensors. The performance of the resulting miRNA sensors was assessed by flow cytometry in single stable transgenic mESCs undergoing self-renewal or differentiation. EF1α promoters arranged back-to-back failed to drive the robustly correlated expression of two transgenes. Back-to-back PGK promoters were shut down during mESC differentiation. However, we found that a back-to-back arrangement of CAG promoters with four CMV enhancers provided both robust expression in mESCs undergoing differentiation and the best signal-to-noise for measurement of miRNA activity in single cells among all the sensors we tested. Such a bidirectional promoter is therefore particularly well suited to study the dynamics of miRNA expression during cell fate transitions at the single cell level.

  4. Bidirectional Promoter Engineering for Single Cell MicroRNA Sensors in Embryonic Stem Cells.

    PubMed

    Sladitschek, Hanna L; Neveu, Pierre A

    2016-01-01

    MicroRNAs have emerged as important markers and regulators of cell identity. Precise measurements of cellular miRNA levels rely traditionally on RNA extraction and thus do not allow to follow miRNA expression dynamics at the level of single cells. Non-invasive miRNA sensors present an ideal solution but they critically depend on the performance of suitable ubiquitous promoters that reliably drive expression both in pluripotent and differentiated cell types. Here we describe the engineering of bidirectional promoters that drive the expression of precise ratiometric fluorescent miRNA sensors in single mouse embryonic stem cells (mESCs) and their differentiated derivatives. These promoters are based on combinations of the widely used CAG, EF1α and PGK promoters as well as the CMV and PGK enhancers. miR-142-3p, which is known to be bimodally expressed in mESCs, served as a model miRNA to gauge the precision of the sensors. The performance of the resulting miRNA sensors was assessed by flow cytometry in single stable transgenic mESCs undergoing self-renewal or differentiation. EF1α promoters arranged back-to-back failed to drive the robustly correlated expression of two transgenes. Back-to-back PGK promoters were shut down during mESC differentiation. However, we found that a back-to-back arrangement of CAG promoters with four CMV enhancers provided both robust expression in mESCs undergoing differentiation and the best signal-to-noise for measurement of miRNA activity in single cells among all the sensors we tested. Such a bidirectional promoter is therefore particularly well suited to study the dynamics of miRNA expression during cell fate transitions at the single cell level. PMID:27152616

  5. Structure Sensor for mobile markerless augmented reality

    NASA Astrophysics Data System (ADS)

    Kilgus, T.; Bux, R.; Franz, A. M.; Johnen, W.; Heim, E.; Fangerau, M.; Müller, M.; Yen, K.; Maier-Hein, L.

    2016-03-01

    3D Visualization of anatomical data is an integral part of diagnostics and treatment in many medical disciplines, such as radiology, surgery and forensic medicine. To enable intuitive interaction with the data, we recently proposed a new concept for on-patient visualization of medical data which involves rendering of subsurface structures on a mobile display that can be moved along the human body. The data fusion is achieved with a range imaging device attached to the display. The range data is used to register static 3D medical imaging data with the patient body based on a surface matching algorithm. However, our previous prototype was based on the Microsoft Kinect camera and thus required a cable connection to acquire color and depth data. The contribution of this paper is two-fold. Firstly, we replace the Kinect with the Structure Sensor - a novel cable-free range imaging device - to improve handling and user experience and show that the resulting accuracy (target registration error: 4.8+/-1.5 mm) is comparable to that achieved with the Kinect. Secondly, a new approach to visualizing complex 3D anatomy based on this device, as well as 3D printed models of anatomical surfaces, is presented. We demonstrate that our concept can be applied to in vivo data and to a 3D printed skull of a forensic case. Our new device is the next step towards clinical integration and shows that the concept cannot only be applied during autopsy but also for presentation of forensic data to laypeople in court or medical education.

  6. An Efficient Micro Control Unit with a Reconfigurable Filter Design for Wireless Body Sensor Networks (WBSNs)

    PubMed Central

    Chen, Chiung-An; Chen, Shih-Lun; Huang, Hong-Yi; Luo, Ching-Hsing

    2012-01-01

    In this paper, a low-cost, low-power and high performance micro control unit (MCU) core is proposed for wireless body sensor networks (WBSNs). It consists of an asynchronous interface, a register bank, a reconfigurable filter, a slop-feature forecast, a lossless data encoder, an error correct coding (ECC) encoder, a UART interface, a power management (PWM), and a multi-sensor controller. To improve the system performance and expansion abilities, the asynchronous interface is added for handling signal exchanges between different clock domains. To eliminate the noise of various bio-signals, the reconfigurable filter is created to provide the functions of average, binomial and sharpen filters. The slop-feature forecast and the lossless data encoder is proposed to reduce the data of various biomedical signals for transmission. Furthermore, the ECC encoder is added to improve the reliability for the wireless transmission and the UART interface is employed the proposed design to be compatible with wireless devices. For long-term healthcare monitoring application, a power management technique is developed for reducing the power consumption of the WBSN system. In addition, the proposed design can be operated with four different bio-sensors simultaneously. The proposed design was successfully tested with a FPGA verification board. The VLSI architecture of this work contains 7.67-K gate counts and consumes the power of 5.8 mW or 1.9 mW at 100 MHz or 133 MHz processing rate using a TSMC 0.18 μm or 0.13 μm CMOS process. Compared with previous techniques, this design achieves higher performance, more functions, more flexibility and higher compatibility than other micro controller designs. PMID:23443375

  7. On the modeling of a piezoellectrically actuated micro-sensor for measurement of microscale fluid physical properties

    NASA Astrophysics Data System (ADS)

    Ghanbari, Mina; Hossainpour, Siamak; Rezazadeh, Ghader

    2015-11-01

    This paper deals with the analysis of a novel micro-electromechanical sensor for measurement of microscale fluid physical properties. The proposed sensor is made up of a micro-beam with one end fixed and a micro-plate as a sensing element at its free end, which is immersed in a microscale fluid media. As fluids show different behavior in microscale than in macroscale, the microscale fluid media have been modeled based on micro-polar theory. So non-classical properties of fluid that are absent in macroscale flows need to be measured. In order to actuate the sensor longitudinally, an AC voltage is applied to the piezoelectric layers on the upper and lower surfaces of the micro-beam. Coupled governing partial differential equations of motion of the fluid field and longitudinal vibration of the micro-beam have been derived based on micro-polar theory. The obtained governing differential equations with time-varying boundary conditions have been simplified and transformed to an enhanced form with homogenous boundary conditions. Then, they have been discretized over the beam and fluid domain using Galerkin-based reduced-order model. The dynamic response of the sensing element for different piezoelectric actuation voltages and different exciting frequencies has been studied. It has been shown that by investigating damping and inertial effect fluid loading on response of the micro-beam, properties of a microscale fluid can be measured. At the end, effects of geometrical parameters of the sensor on the response of sensing element have been studied.

  8. A Fully Integrated and Miniaturized Heavy-metal-detection Sensor Based on Micro-patterned Reduced Graphene Oxide

    NASA Astrophysics Data System (ADS)

    Xuan, Xing; Hossain, Md. Faruk; Park, Jae Yeong

    2016-09-01

    For this paper, a fully integrated and highly miniaturized electrochemical sensor was designed and fabricated on a silicon substrate. A solvothermal-assisted reduced graphene oxide named “TRGO” was then successfully micro-patterned using a lithography technique, followed by the electrodeposition of bismuth (Bi) on the surface of the micro-patterned TRGO for the electrochemical detection of heavy metal ions. The fully integrated electrochemical micro-sensor was then measured and evaluated for the detection of cadmium and lead-heavy metal ions in an acetic-acid buffered solution using the square wave anodic stripping voltammetry (SWASV) technique. The fabricated micro-sensor exhibited a linear detection range of 1.0 μg L‑1 to 120.0 μg L‑1 for both of the metal ions, and detection limits of 0.4 μg L‑1 and 1.0 μg L‑1 were recorded for the lead and cadmium (S/N = 3), respectively. Drinking-water samples were used for the practical assessment of the fabricated micro-sensor, and it showed an acceptable detection performance regarding the metal ions.

  9. A Fully Integrated and Miniaturized Heavy-metal-detection Sensor Based on Micro-patterned Reduced Graphene Oxide.

    PubMed

    Xuan, Xing; Hossain, Md Faruk; Park, Jae Yeong

    2016-09-12

    For this paper, a fully integrated and highly miniaturized electrochemical sensor was designed and fabricated on a silicon substrate. A solvothermal-assisted reduced graphene oxide named "TRGO" was then successfully micro-patterned using a lithography technique, followed by the electrodeposition of bismuth (Bi) on the surface of the micro-patterned TRGO for the electrochemical detection of heavy metal ions. The fully integrated electrochemical micro-sensor was then measured and evaluated for the detection of cadmium and lead-heavy metal ions in an acetic-acid buffered solution using the square wave anodic stripping voltammetry (SWASV) technique. The fabricated micro-sensor exhibited a linear detection range of 1.0 μg L(-1) to 120.0 μg L(-1) for both of the metal ions, and detection limits of 0.4 μg L(-1) and 1.0 μg L(-1) were recorded for the lead and cadmium (S/N = 3), respectively. Drinking-water samples were used for the practical assessment of the fabricated micro-sensor, and it showed an acceptable detection performance regarding the metal ions.

  10. A Fully Integrated and Miniaturized Heavy-metal-detection Sensor Based on Micro-patterned Reduced Graphene Oxide

    PubMed Central

    Xuan, Xing; Hossain, Md. Faruk; Park, Jae Yeong

    2016-01-01

    For this paper, a fully integrated and highly miniaturized electrochemical sensor was designed and fabricated on a silicon substrate. A solvothermal-assisted reduced graphene oxide named “TRGO” was then successfully micro-patterned using a lithography technique, followed by the electrodeposition of bismuth (Bi) on the surface of the micro-patterned TRGO for the electrochemical detection of heavy metal ions. The fully integrated electrochemical micro-sensor was then measured and evaluated for the detection of cadmium and lead-heavy metal ions in an acetic-acid buffered solution using the square wave anodic stripping voltammetry (SWASV) technique. The fabricated micro-sensor exhibited a linear detection range of 1.0 μg L−1 to 120.0 μg L−1 for both of the metal ions, and detection limits of 0.4 μg L−1 and 1.0 μg L−1 were recorded for the lead and cadmium (S/N = 3), respectively. Drinking-water samples were used for the practical assessment of the fabricated micro-sensor, and it showed an acceptable detection performance regarding the metal ions. PMID:27616629

  11. A Fully Integrated and Miniaturized Heavy-metal-detection Sensor Based on Micro-patterned Reduced Graphene Oxide.

    PubMed

    Xuan, Xing; Hossain, Md Faruk; Park, Jae Yeong

    2016-01-01

    For this paper, a fully integrated and highly miniaturized electrochemical sensor was designed and fabricated on a silicon substrate. A solvothermal-assisted reduced graphene oxide named "TRGO" was then successfully micro-patterned using a lithography technique, followed by the electrodeposition of bismuth (Bi) on the surface of the micro-patterned TRGO for the electrochemical detection of heavy metal ions. The fully integrated electrochemical micro-sensor was then measured and evaluated for the detection of cadmium and lead-heavy metal ions in an acetic-acid buffered solution using the square wave anodic stripping voltammetry (SWASV) technique. The fabricated micro-sensor exhibited a linear detection range of 1.0 μg L(-1) to 120.0 μg L(-1) for both of the metal ions, and detection limits of 0.4 μg L(-1) and 1.0 μg L(-1) were recorded for the lead and cadmium (S/N = 3), respectively. Drinking-water samples were used for the practical assessment of the fabricated micro-sensor, and it showed an acceptable detection performance regarding the metal ions. PMID:27616629

  12. Micro/Nano gas sensors: a new strategy towards in-situ wafer-level fabrication of high-performance gas sensing chips.

    PubMed

    Xu, Lei; Dai, Zhengfei; Duan, Guotao; Guo, Lianfeng; Wang, Yi; Zhou, Hong; Liu, Yanxiang; Cai, Weiping; Wang, Yuelin; Li, Tie

    2015-05-22

    Nano-structured gas sensing materials, in particular nanoparticles, nanotubes, and nanowires, enable high sensitivity at a ppb level for gas sensors. For practical applications, it is highly desirable to be able to manufacture such gas sensors in batch and at low cost. We present here a strategy of in-situ wafer-level fabrication of the high-performance micro/nano gas sensing chips by naturally integrating microhotplatform (MHP) with nanopore array (NPA). By introducing colloidal crystal template, a wafer-level ordered homogenous SnO2 NPA is synthesized in-situ on a 4-inch MHP wafer, able to produce thousands of gas sensing units in one batch. The integration of micromachining process and nanofabrication process endues micro/nano gas sensing chips at low cost, high throughput, and with high sensitivity (down to ~20 ppb), fast response time (down to ~1 s), and low power consumption (down to ~30 mW). The proposed strategy of integrating MHP with NPA represents a versatile approach for in-situ wafer-level fabrication of high-performance micro/nano gas sensors for real industrial applications.

  13. A bioinspired micro-composite structure

    NASA Astrophysics Data System (ADS)

    Chen, Li

    2005-11-01

    This thesis involves the design, fabrication and mechanical testing of a bioinspired composite structure with characteristic dimensions of the order of tens of microns. The particular microarchitecture, designed and fabricated using microelectromechanical systems (MEMS) technology, involves two distinct length scales and represents a first attempt at mimicking the crossed-lamellar microstructure of the shell of the Giant Queen Conch Strombus gigas , which contains features the dimensions of which span five distinct length scales. After giving a review of the mechanical properties of mollusks, the detailed design of the microstructure, which approximates the crossed-lamellar arrangement of Strombus gigas, is presented. Fabrication of the microstructure using multi-microfabrication methods is conducted in terms of the designed fabrication flow. The problems encountered during the processes are discussed. The measurements of the flexural strength and toughening of the fabricated microstructure are conducted using a commercially available nanoindenter. Testing results are discussed and conclusions about the mechanical behaviors of the microstructure are drawn to summarize the achievement of this thesis. Finally, future work is outlined to point out the possible directions for improving the mechanical performance of the bioinspired composite. In parallel with my thesis research, I have developed a theoretical model for the experimentally observed cyclic loading-induced strengthening in MEMS polycrystalline silicon. The model relies on atomistic calculations that predict plastic-like behavior of amorphous silicon, which depending on initial density, is associated with dilatancy or compaction. The amorphous silicon is approximated as a Drucker-Prager plastic material, whose parameters are chosen to match the predictions of the atomistic calculations. The constitutive model is used to simulate the mechanical response to cyclic loads of notched polysilicon MEMS specimens

  14. Analytical modelling of a refractive index sensor based on an intrinsic micro Fabry-Perot interferometer.

    PubMed

    Vargas-Rodriguez, Everardo; Guzman-Chavez, Ana D; Cano-Contreras, Martin; Gallegos-Arellano, Eloisa; Jauregui-Vazquez, Daniel; Hernández-García, Juan C; Estudillo-Ayala, Julian M; Rojas-Laguna, Roberto

    2015-10-15

    In this work a refractive index sensor based on a combination of the non-dispersive sensing (NDS) and the Tunable Laser Spectroscopy (TLS) principles is presented. Here, in order to have one reference and one measurement channel a single-beam dual-path configuration is used for implementing the NDS principle. These channels are monitored with a couple of identical optical detectors which are correlated to calculate the overall sensor response, called here the depth of modulation. It is shown that this is useful to minimize drifting errors due to source power variations. Furthermore, a comprehensive analysis of a refractive index sensing setup, based on an intrinsic micro Fabry-Perot Interferometer (FPI) is described. Here, the changes over the FPI pattern as the exit refractive index is varied are analytically modelled by using the characteristic matrix method. Additionally, our simulated results are supported by experimental measurements which are also provided. Finally it is shown that by using this principle a simple refractive index sensor with a resolution in the order of 2.15 × 10(-4) RIU can be implemented by using a couple of standard and low cost photodetectors.

  15. Design and Analysis of a Single-Camera Omnistereo Sensor for Quadrotor Micro Aerial Vehicles (MAVs).

    PubMed

    Jaramillo, Carlos; Valenti, Roberto G; Guo, Ling; Xiao, Jizhong

    2016-02-06

    We describe the design and 3D sensing performance of an omnidirectional stereo (omnistereo) vision system applied to Micro Aerial Vehicles (MAVs). The proposed omnistereo sensor employs a monocular camera that is co-axially aligned with a pair of hyperboloidal mirrors (a vertically-folded catadioptric configuration). We show that this arrangement provides a compact solution for omnidirectional 3D perception while mounted on top of propeller-based MAVs (not capable of large payloads). The theoretical single viewpoint (SVP) constraint helps us derive analytical solutions for the sensor's projective geometry and generate SVP-compliant panoramic images to compute 3D information from stereo correspondences (in a truly synchronous fashion). We perform an extensive analysis on various system characteristics such as its size, catadioptric spatial resolution, field-of-view. In addition, we pose a probabilistic model for the uncertainty estimation of 3D information from triangulation of back-projected rays. We validate the projection error of the design using both synthetic and real-life images against ground-truth data. Qualitatively, we show 3D point clouds (dense and sparse) resulting out of a single image captured from a real-life experiment. We expect the reproducibility of our sensor as its model parameters can be optimized to satisfy other catadioptric-based omnistereo vision under different circumstances.

  16. Analytical Modelling of a Refractive Index Sensor Based on an Intrinsic Micro Fabry-Perot Interferometer

    PubMed Central

    Vargas-Rodriguez, Everardo; Guzman-Chavez, Ana D.; Cano-Contreras, Martin; Gallegos-Arellano, Eloisa; Jauregui-Vazquez, Daniel; Hernández-García, Juan C.; Estudillo-Ayala, Julian M.; Rojas-Laguna, Roberto

    2015-01-01

    In this work a refractive index sensor based on a combination of the non-dispersive sensing (NDS) and the Tunable Laser Spectroscopy (TLS) principles is presented. Here, in order to have one reference and one measurement channel a single-beam dual-path configuration is used for implementing the NDS principle. These channels are monitored with a couple of identical optical detectors which are correlated to calculate the overall sensor response, called here the depth of modulation. It is shown that this is useful to minimize drifting errors due to source power variations. Furthermore, a comprehensive analysis of a refractive index sensing setup, based on an intrinsic micro Fabry-Perot Interferometer (FPI) is described. Here, the changes over the FPI pattern as the exit refractive index is varied are analytically modelled by using the characteristic matrix method. Additionally, our simulated results are supported by experimental measurements which are also provided. Finally it is shown that by using this principle a simple refractive index sensor with a resolution in the order of 2.15 × 10−4 RIU can be implemented by using a couple of standard and low cost photodetectors. PMID:26501277

  17. Analytical modelling of a refractive index sensor based on an intrinsic micro Fabry-Perot interferometer.

    PubMed

    Vargas-Rodriguez, Everardo; Guzman-Chavez, Ana D; Cano-Contreras, Martin; Gallegos-Arellano, Eloisa; Jauregui-Vazquez, Daniel; Hernández-García, Juan C; Estudillo-Ayala, Julian M; Rojas-Laguna, Roberto

    2015-01-01

    In this work a refractive index sensor based on a combination of the non-dispersive sensing (NDS) and the Tunable Laser Spectroscopy (TLS) principles is presented. Here, in order to have one reference and one measurement channel a single-beam dual-path configuration is used for implementing the NDS principle. These channels are monitored with a couple of identical optical detectors which are correlated to calculate the overall sensor response, called here the depth of modulation. It is shown that this is useful to minimize drifting errors due to source power variations. Furthermore, a comprehensive analysis of a refractive index sensing setup, based on an intrinsic micro Fabry-Perot Interferometer (FPI) is described. Here, the changes over the FPI pattern as the exit refractive index is varied are analytically modelled by using the characteristic matrix method. Additionally, our simulated results are supported by experimental measurements which are also provided. Finally it is shown that by using this principle a simple refractive index sensor with a resolution in the order of 2.15 × 10(-4) RIU can be implemented by using a couple of standard and low cost photodetectors. PMID:26501277

  18. Tooth structural health monitoring with a fiber optic microbend sensor

    NASA Astrophysics Data System (ADS)

    Kishen, A.; Rafique, A.

    2006-02-01

    The purpose of this study is to monitor structural response in intact teeth and teeth with structural loss using a noninvasive fiber optic microbend (FOMB) sensor. In this study a miniature fiber optic microbend sensor is fabricated and tested on intact tooth specimens, tooth specimens in which one-third crown structure was removed, tooth specimens in which access cavity was prepared and tooth specimens in which access cavity and root canal were prepared. The microbend sensor displayed a direct relationship between the applied load and the output light intensity. The rate of change in light intensity with increase in loads corresponded with the structural response of the tooth. This experiment highlights the potential of FOMB sensor technology to quantitatively monitor tooth structural loss during post endodontic restorations.

  19. Erbium-doped fiber amplifier elements for structural analysis sensors

    NASA Technical Reports Server (NTRS)

    Hanna-Hawver, P.; Kamdar, K. D.; Mehta, S.; Nagarajan, S.; Nasta, M. H.; Claus, R. O.

    1992-01-01

    The use of erbium-doped fiber amplifiers (EDFA's) in optical fiber sensor systems for structural analysis is described. EDFA's were developed for primary applications as periodic regenerator amplifiers in long-distance fiber-based communication systems. Their in-line amplification performance also makes them attractive for optical fiber sensor systems which require long effective lengths or the synthesis of special length-dependent signal processing functions. Sensor geometries incorporating EDFA's in recirculating and multiple loop sensors are discussed. Noise and polarization birefringence are also considered, and the experimental development of system components is discussed.

  20. Micro Structure of Nickel in Spin Coated Thin Film Magnets

    NASA Astrophysics Data System (ADS)

    Vides, Katherine; Dahanayake, Rasika; Samarasekara, Pubudu; Dehipawala, Sunil

    2014-03-01

    Micro-Structure of Nickel compounds in thin film magnets was investigated using Extended X ray Absorption Fine Structure (EXAFS) and X-ray Absorption Near Edge Structure (XANES). These thin film magnets were prepared by spin coating several layers of precursor containing iron and Nickel on a glass substrate. Thickness of the films was controlled by spin rate. Several magnets were prepared with different thicknesses and each film was annealed to either 200C or 350c in air. Variation of oxidation state and nearest neighbor bond lengths of each magnet was measured to characterize Ni in the film.

  1. Optical fiber sensors and signal processing for intelligent structure monitoring

    NASA Technical Reports Server (NTRS)

    Rogowski, Robert; Claus, R. O.; Lindner, D. K.; Thomas, Daniel; Cox, Dave

    1988-01-01

    The analytic and experimental performance of optical fiber sensors for the control of vibration of large aerospace and other structures are investigated. In particular, model domain optical fiber sensor systems, are being studied due to their apparent potential as distributed, low mass sensors of vibration over appropriate ranges of both low frequency and low amplitude displacements. Progress during the past three months is outlined. Progress since September is divided into work in the areas of experimental hardware development, analytical analysis, control design and sensor development. During the next six months, tests of a prototype closed-loop control system for a beam are planned which will demonstrate the solution of several optical fiber instrumentation device problems, the performance of the control system theory which incorporates the model of the modal domain sensor, and the potential for distributed control which this sensor approach offers.

  2. Enhanced Ion Acceleration from Micro-tube Structured Targets

    NASA Astrophysics Data System (ADS)

    Snyder, Joseph; Ji, Liangliang; Akli, Kramer

    2015-11-01

    We present an enhanced ion acceleration method that leverages recent advancements in 3D printing for target fabrication. Using the three-dimensional Particle-in-Cell simulation code Virtual Laser-Plasma Lab (VLPL), we model the interaction of a short pulse, high intensity laser with a micro-tube plasma (MTP) structured target. When compared to flat foils, the MTP target enhances the maximum proton energy by a factor of about 4. The ion enhancement is attributed to two main factors: high energy electrons extracted from the tube structure enhancing the accelerating field and light intensification within the MTP target increasing the laser intensity at the location of the foil. We also present results on ion energy scaling with micro-tube diameter and incident laser pulse intensity. This work was supported by the AFOSR under contract No. FA9550-14-1-0085.

  3. Embedded Sensor Array Development for Composite Structure Integrity Monitoring

    SciTech Connect

    Kumar, A.; Bryan, W. L.; Clonts, L. G.; Franks, S.

    2007-06-26

    The purpose of this Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC (the "Contractor") and Accellent Technologies, Inc. (the "Participant") was for the development of an embedded ultrasonic sensor system for composite structure integrity monitoring.

  4. Effect of annealing on proton irradiated AlGaN/GaN based micro-Hall sensors

    SciTech Connect

    Abderrahmane, A.; Takahashi, H.; Tashiro, T.; Ko, P. J.; Okada, H.; Sandhu, A.; Sato, S.; Ohshima, T.

    2014-02-20

    The effect of annealing at 673 K on irradiated micro-Hall sensors irradiated with protons at 380keV and fluences of 10{sup 14}, 10{sup 15} and 10{sup 16} protons/cm{sup 2} is reported. Cathodoluminescence measurements were carried out at room temperature before and after annealing and showed improvement in the band edge band emission of the GaN layer. After annealing a sensor irradiated by 10{sup 15} protons/cm{sup 2} the device became operational with improvements in its magnetic sensitivity. All irradiated sensors showed improvement in their electrical characteristics after annealing.

  5. Fragility estimates of smart structures with sensor faults

    NASA Astrophysics Data System (ADS)

    Kim, Yeesock; Bai, Jong-Wha; Albano, Leonard D.

    2013-12-01

    In this paper, the impact of sensor faults within smart structures is investigated using seismic fragility analysis techniques. Seismic fragility analysis is one of the methods used to evaluate the vulnerability of structural systems under a broad range of earthquake events. It would play an important role in estimating seismic losses and in the decision making process based on vibration control performance of the smart structures during seismic events. In this study, a three-story building employing a highly nonlinear hysteretic magnetorheological (MR) damper is analyzed to estimate the seismic fragility of the smart control system. Different levels of sensor damage scenarios for smart structures are considered to provide a better understanding of the expected fragility estimates due to the impact of sensor failures. Probabilistic demand models are constructed with a Bayesian updating approach while the seismic capacity of smart structures is estimated based on the approximate structural performance of semi-actively controlled structures. Peak ground acceleration (PGA) of ground motion is used as a measure of earthquake intensity. Then the fragility curves for the smart structures are developed and compared with those for the semi-active control systems with different levels of sensor damage scenarios. The responses of an uncontrolled structure are used as a baseline. It is shown from the simulations that the proposed methodology is effective in quantifying the impact of sensor faults within smart structures.

  6. Micro-Drilling of Polymer Tubular Ultramicroelectrode Arrays for Electrochemical Sensors

    PubMed Central

    Kafka, Jan; Skaarup, Steen; Geschke, Oliver; Larsen, Niels B.

    2013-01-01

    We present a reproducible fast prototyping procedure based on micro-drilling to produce homogeneous tubular ultramicroelectrode arrays made from poly(3,4-ethylenedioxythiophene) (PEDOT), a conductive polymer. Arrays of Ø 100 μm tubular electrodes each having a height of 0.37 ± 0.06 μm were reproducibly fabricated. The electrode dimensions were analyzed by SEM after deposition of silver dendrites to visualize the electroactive electrode area. The electrochemical applicability of the electrodes was demonstrated by voltammetric and amperometric detection of ferri-/ferrocyanide. Recorded signals were in agreement with results from finite element modelling of the system. The tubular PEDOT ultramicroelectrode arrays were modified by prussian blue to enable the detection of hydrogen peroxide. A linear sensor response was demonstrated for hydrogen peroxide concentrations from 0.1 mM to 1 mM. PMID:23673674

  7. Micro-drilling of polymer tubular ultramicroelectrode arrays for electrochemical sensors.

    PubMed

    Kafka, Jan; Skaarup, Steen; Geschke, Oliver; Larsen, Niels B

    2013-05-14

    We present a reproducible fast prototyping procedure based on micro-drilling to produce homogeneous tubular ultramicroelectrode arrays made from poly(3,4-ethylenedioxythiophene) (PEDOT), a conductive polymer. Arrays of Ø 100 µm tubular electrodes each having a height of 0.37 ± 0.06 µm were reproducibly fabricated. The electrode dimensions were analyzed by SEM after deposition of silver dendrites to visualize the electroactive electrode area. The electrochemical applicability of the electrodes was demonstrated by voltammetric and amperometric detection of ferri-/ferrocyanide. Recorded signals were in agreement with results from finite element modelling of the system. The tubular PEDOT ultramicroelectrode arrays were modified by prussian blue to enable the detection of hydrogen peroxide. A linear sensor response was demonstrated for hydrogen peroxide concentrations from 0.1 mM to 1 mM.

  8. MicroRNA Sensor Based on Magnetic Beads and Enzymatic Probes

    NASA Astrophysics Data System (ADS)

    Zhang, Yue; Zhou, Dejian; He, Junhui

    2014-12-01

    MicroRNAs are associated with multiple cellular processes and diseases. Here, we designed a highly sensitive, magnetically retrievable biosensor using magnetic beads (MBs) as a model RNA sensor. The assay utilized two biotinylated probes, which were hybridized to the complementary target miRNA in a sandwich assay format. One of the biotinylated ends of the hybridization complex was immobilized onto the surface of a NeutrAvidin (NAV) coated MB and the other biotinylated end was conjugated to HRP via NAV-biotin interaction. The results were presented by colorimetric absorbance of the resorufin product from amplex red oxidation. We show that by combining the use of MBs as well as bio-specific immobilization, the sensitivity of miRNA detection is down to 100 pM. This model HRP-MBs system can be used for simple, rapid colorimetric quantification of low level DNA/RNA or other small molecules.

  9. Micro-plasticity and intermittent dislocation activity in a simplified micro-structural model

    NASA Astrophysics Data System (ADS)

    Derlet, P. M.; Maaß, R.

    2013-04-01

    Here we present a model to study the micro-plastic regime of a stress-strain curve. In this model an explicit dislocation population represents the mobile dislocation content and an internal shear-stress field represents a mean-field description of the immobile dislocation content. The mobile dislocations are constrained to a simple dipolar mat geometry and modelled via a dislocation dynamics (DD) algorithm, whilst the shear-stress field is chosen to be a sinusoidal function of distance along the mat direction. The sinusoidal function, defined by a periodic length and a shear-stress amplitude, is interpreted to represent a pre-existing micro-structure. These model parameters, along with the mobile dislocation density, are found to admit a diversity of micro-plastic behaviour involving intermittent plasticity in the form of a scale-free avalanche phenomenon, with an exponent and scaling-collapse for the strain-burst magnitude distribution that is in agreement with mean-field theory and similar to that seen in experiment and more complex DD simulations.

  10. Using micro-sensor data to quantify macro kinematics of classical cross-country skiing during on-snow training.

    PubMed

    Marsland, Finn; Mackintosh, Colin; Anson, Judith; Lyons, Keith; Waddington, Gordon; Chapman, Dale W

    2015-01-01

    Micro-sensors were used to quantify macro kinematics of classical cross-country skiing techniques and measure cycle rates and cycle lengths during on-snow training. Data were collected from seven national level participants skiing at two submaximal intensities while wearing a micro-sensor unit (MinimaxX™). Algorithms were developed identifying double poling (DP), diagonal striding (DS), kick-double poling (KDP), tucking (Tuck), and turning (Turn). Technique duration (T-time), cycle rates, and cycle counts were compared to video-derived data to assess system accuracy. There was good reliability between micro-sensor and video calculated cycle rates for DP, DS, and KDP, with small mean differences (Mdiff% = -0.2 ± 3.2, -1.5 ± 2.2 and -1.4 ± 6.2) and trivial to small effect sizes (ES = 0.20, 0.30 and 0.13). Very strong correlations were observed for DP, DS, and KDP for T-time (r = 0.87-0.99) and cycle count (r = 0.87-0.99), while mean values were under-reported by the micro-sensor. Incorrect Turn detection was a major factor in technique cycle misclassification. Data presented highlight the potential of automated ski technique classification in cross-country skiing research. With further refinement, this approach will allow many applied questions associated with pacing, fatigue, technique selection and power output during training and competition to be answered.

  11. Micro-Displacement Sensor Based on a Hollow-Core Photonic Crystal Fiber

    PubMed Central

    Pinto, Ana Margarida Rodrigues; Baptista, José Manuel; Santos, José Luís; Lopez-Amo, Manuel; Frazão, Orlando

    2012-01-01

    A sensing head based on a hollow-core photonic crystal fiber for in-reflection measurement of micro-displacements is presented. The sensing structure takes advantage of the multimodal behavior of a short segment of hollow-core photonic crystal fiber in-reflection, being spliced to a single mode fiber at its other end. A modal interferometer is obtained when the sensing head is close to a mirror, through which displacement is measured. PMID:23247414

  12. Sensitivity and noise of micro-Hall magnetic sensors based on InGaAs quantum wells

    NASA Astrophysics Data System (ADS)

    Chenaud, B.; Segovia-Mera, A.; Delgard, A.; Feltin, N.; Hoffmann, A.; Pascal, F.; Zawadzki, W.; Mailly, D.; Chaubet, C.

    2016-01-01

    We study the room-temperature performance of micro-Hall magnetic sensors based on pseudomorphic InGaAs quantum wells. Active areas of our sensors range from 1 to 80 μm. We focus on the smallest detectable magnetic fields in small sensors and perform a systematic study of noise at room temperature in the frequency range between 1 Hz and 100 kHz. Our data are interpreted by the mobility fluctuation model. The Hooge parameter is determined for the applied technology. We show that, independently of the experimental frequency, the ratio of sensitivity to noise is proportional to characteristic length of the sensor. The resolution of 1 mG/√{Hz } is achievable in a 3 μm sensor at room temperature.

  13. Reagentless, Structure-Switching, Electrochemical Aptamer-Based Sensors

    NASA Astrophysics Data System (ADS)

    Schoukroun-Barnes, Lauren R.; Macazo, Florika C.; Gutierrez, Brenda; Lottermoser, Justine; Liu, Juan; White, Ryan J.

    2016-06-01

    The development of structure-switching, electrochemical, aptamer-based sensors over the past ˜10 years has led to a variety of reagentless sensors capable of analytical detection in a range of sample matrices. The crux of this methodology is the coupling of target-induced conformation changes of a redox-labeled aptamer with electrochemical detection of the resulting altered charge transfer rate between the redox molecule and electrode surface. Using aptamer recognition expands the highly sensitive detection ability of electrochemistry to a range of previously inaccessible analytes. In this review, we focus on the methods of sensor fabrication and how sensor signaling is affected by fabrication parameters. We then discuss recent studies addressing the fundamentals of sensor signaling as well as quantitative characterization of the analytical performance of electrochemical aptamer-based sensors. Although the limits of detection of reported electrochemical aptamer-based sensors do not often reach that of gold-standard methods such as enzyme-linked immunosorbent assays, the operational convenience of the sensor platform enables exciting analytical applications that we address. Using illustrative examples, we highlight recent advances in the field that impact important areas of analytical chemistry. Finally, we discuss the challenges and prospects for this class of sensors.

  14. Reagentless, Structure-Switching, Electrochemical Aptamer-Based Sensors.

    PubMed

    Schoukroun-Barnes, Lauren R; Macazo, Florika C; Gutierrez, Brenda; Lottermoser, Justine; Liu, Juan; White, Ryan J

    2016-06-12

    The development of structure-switching, electrochemical, aptamer-based sensors over the past ∼10 years has led to a variety of reagentless sensors capable of analytical detection in a range of sample matrices. The crux of this methodology is the coupling of target-induced conformation changes of a redox-labeled aptamer with electrochemical detection of the resulting altered charge transfer rate between the redox molecule and electrode surface. Using aptamer recognition expands the highly sensitive detection ability of electrochemistry to a range of previously inaccessible analytes. In this review, we focus on the methods of sensor fabrication and how sensor signaling is affected by fabrication parameters. We then discuss recent studies addressing the fundamentals of sensor signaling as well as quantitative characterization of the analytical performance of electrochemical aptamer-based sensors. Although the limits of detection of reported electrochemical aptamer-based sensors do not often reach that of gold-standard methods such as enzyme-linked immunosorbent assays, the operational convenience of the sensor platform enables exciting analytical applications that we address. Using illustrative examples, we highlight recent advances in the field that impact important areas of analytical chemistry. Finally, we discuss the challenges and prospects for this class of sensors.

  15. Optical fiber sensors for characterization of materials and structures

    NASA Astrophysics Data System (ADS)

    Claus, Richard O.; Murphy, Kent A.

    1994-08-01

    Optical fiber systems have been developed during the past twenty-five years for primary applications in the high speed digital communication of information. Using much of the same rapidly-developing technology optical fiber sensor systems have been developed during the past fifteen years for the measurement of a wide range of physical observables and applications in aerospace and hydrospace, civil structures and biomedical instrumentation systems. The major advantage of optical fiber sensor methods over conventional sensor systems is the all-dielectric nature of the fiber and the intrinsic avoidance of electromagnetic interference and ground loops that plague wire and metal-based sensing networks. For physical property measurements in smart materials where actuator elements and arrays are driven by high voltage electrical signals, such immunity is especially important. Another major advantage is the operation of fiber sensors above the temperatures at which most conventional sensor instrumentation will not operate. Such operation allows the use of properly designed fiber sensors in situ for the analysis of the fabrication conditions of smart materials, as well as their performance in high temperature environments. Sensor elements incorporated into the material during fabrication may in some cases be used for material evaluation post processing. This paper briefly suggests the use of such optical fiber sensor elements during the fabrication, inservice lifetimes and damage and degradation phases of smart material and structural systems.

  16. A Wireless Magnetic Resonance Energy Transfer System for Micro Implantable Medical Sensors

    PubMed Central

    Li, Xiuhan; Zhang, Hanru; Peng, Fei; Li, Yang; Yang, Tianyang; Wang, Bo; Fang, Dongming

    2012-01-01

    Based on the magnetic resonance coupling principle, in this paper a wireless energy transfer system is designed and implemented for the power supply of micro-implantable medical sensors. The entire system is composed of the in vitro part, including the energy transmitting circuit and resonant transmitter coils, and in vivo part, including the micro resonant receiver coils and signal shaping chip which includes the rectifier module and LDO voltage regulator module. Transmitter and receiver coils are wound by Litz wire, and the diameter of the receiver coils is just 1.9 cm. The energy transfer efficiency of the four-coil system is greatly improved compared to the conventional two-coil system. When the distance between the transmitter coils and the receiver coils is 1.5 cm, the transfer efficiency is 85% at the frequency of 742 kHz. The power transfer efficiency can be optimized by adding magnetic enhanced resonators. The receiving voltage signal is converted to a stable output voltage of 3.3 V and a current of 10 mA at the distance of 2 cm. In addition, the output current varies with changes in the distance. The whole implanted part is packaged with PDMS of excellent biocompatibility and the volume of it is about 1 cm3. PMID:23112600

  17. Micro Infrared Earth Sensor project: an integrated IR camera for Earth remote sensing

    NASA Astrophysics Data System (ADS)

    Soto-Romero, Georges; Bony, Francis; Simonne, Jean-Jacques; Fourniols, Jean-Yves

    2001-12-01

    MEMS technology now makes possible to produce active microdevices combining detection, signal processing, and data storage with accuracy and compactness. In view of their characteristics, it can be expected that such microsensors will be used extensively in space applications dedicated to micro and nano satellites. The advanced architecture of a MicroInfraRedEarthSensor generic system based on a Vox microbolometer array associated with optics and electronics 'on the shelves' for signal processing and depointing computation, used to control the attitude of satellites in low earth orbits, has been completely developed, through the design of a virtual prototype combined with a breadboard implementation of an IR camera (called MST, and has been developed by EADS-SODERN, in the frame of IASI project). The correlation of the virtual prototyping approach, has allowed to build one complete optical head part of the instrument with efficient and optimized parameters where the performances are consistent with the main mission specifications (pointing accuracy 10 Hz, aperture angle: > 36 degree(s), volume

  18. Novel position sensor technologies for microaccelerometers

    NASA Technical Reports Server (NTRS)

    Vanzandt, T. R.; Kenny, T. W.; Kaiser, W. J.

    1992-01-01

    An important new approach for vehicle guidance and control is based on the use of compact, low-mass, low-cost sensors integrated with the vehicle structure. Many advantages of this approach lead to new capabilities. However, the development of compact guidance and control sensors leads to a variety of fundamental physical problems associated with sensor sensitivity and noise. For example, as sensor size is reduced, it becomes necessary to improve the sensitivity of the sensor signal detection mechanism. These challenges to sensor development will be described. Recent developments at JPL, based on new position sensor principles such as electron tunneling, have produced a series of novel, ultra-high sensitivity micro-sensors and micro-instruments. Included among the applications demonstrated, are a high sensitivity micro-accelerometer and micro-seismometer. In this paper, the fundamental limits of conventional position sensors will be discussed and a new position sensor for advanced accelerometers will be described.

  19. Research on micro-sized acoustic bandgap structures.

    SciTech Connect

    Fleming, James Grant; McCormick, Frederick Bossert; Su, Mehmet F.; El-Kady, Ihab Fathy; Olsson, Roy H., III; Tuck, Melanie R.

    2010-01-01

    Phononic crystals (or acoustic crystals) are the acoustic wave analogue of photonic crystals. Here a periodic array of scattering inclusions located in a homogeneous host material forbids certain ranges of acoustic frequencies from existence within the crystal, thus creating what are known as acoustic (or phononic) bandgaps. The vast majority of phononic crystal devices reported prior to this LDRD were constructed by hand assembling scattering inclusions in a lossy viscoelastic medium, predominantly air, water or epoxy, resulting in large structures limited to frequencies below 1 MHz. Under this LDRD, phononic crystals and devices were scaled to very (VHF: 30-300 MHz) and ultra (UHF: 300-3000 MHz) high frequencies utilizing finite difference time domain (FDTD) modeling, microfabrication and micromachining technologies. This LDRD developed key breakthroughs in the areas of micro-phononic crystals including physical origins of phononic crystals, advanced FDTD modeling and design techniques, material considerations, microfabrication processes, characterization methods and device structures. Micro-phononic crystal devices realized in low-loss solid materials were emphasized in this work due to their potential applications in radio frequency communications and acoustic imaging for medical ultrasound and nondestructive testing. The results of the advanced modeling, fabrication and integrated transducer designs were that this LDRD produced the 1st measured phononic crystals and phononic crystal devices (waveguides) operating in the VHF (67 MHz) and UHF (937 MHz) frequency bands and established Sandia as a world leader in the area of micro-phononic crystals.

  20. Mechatronic Scanning System with Integrated Micro Electro Mechanical System Position Sensors

    NASA Astrophysics Data System (ADS)

    Stavrov, Vladimir; Chakarov, Dimitar; Shulev, Assen; Tsveov, Mihail

    2016-06-01

    In this paper, a study of a mechatronic scanning system for application in the microbiology, microelectronics research, chemistry, etc. is presented. Integrated silicon micro electro mechanical system (MEMS) position sensor is used for monitoring the displacement of the scanning system. The utilized silicon MEMS sensors with sidewall embedded piezoresistors possess a number of key advantages such as high sensitivity, low noise and extremely low temperature dependence. Design of 2D scanning system with a travel range of 22 × 22 μm2 has been presented in present work. This system includes a Compliant Transmission Mechanism, (CTM) designed as a complex elastic mechanism, comprising four parallelograms. Computer aided desigh (CAD) model and finite element analysis (FEA) of the Compliant Transmission Mechanism mechanisms have been carried out. A prototype of the scanning system is fabricated, based on CAD model. An experimental set-up of an optical system and a correlation technique for digital image processing have been used for testing the scanning system prototype. Results of the experimental investigations of the prototyped scanning system are also presented.

  1. The Transition-Edge-Sensor Array for the Micro-X Sounding Rocket

    NASA Technical Reports Server (NTRS)

    Eckart, M. E.; Adams, J. S.; Bailey, C. N.; Bandler, S. R.; Busch, Sarah Elizabeth; Chervenak J. A.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.; Porst, J. P.; Porter, F. S.; Sadleir, J. E.; Smith, Stephen J.; Figueroa-Feliciano, Enectali

    2012-01-01

    The Micro-X sounding rocket program will fly a 128-element array of transition-edge-sensor microcalorimeters to enable high-resolution X-ray imaging spectroscopy of the Puppis-A supernova remnant. To match the angular resolution of the optics while maximizing the field-of-view and retaining a high energy resolution (< 4 eV at 1 keV), we have designed the pixels using 600 x 600 sq. micron Au/Bi absorbers, which overhang 140 x 140 sq. micron Mo/Au sensors. The data-rate capabilities of the rocket telemetry system require the pulse decay to be approximately 2 ms to allow a significant portion of the data to be telemetered during flight. Here we report experimental results from the flight array, including measurements of energy resolution, uniformity, and absorber thermalization. In addition, we present studies of test devices that have a variety of absorber contact geometries, as well as a variety of membrane-perforation schemes designed to slow the pulse decay time to match the telemetry requirements. Finally, we describe the reduction in pixel-to-pixel crosstalk afforded by an angle-evaporated Cu backside heatsinking layer, which provides Cu coverage on the four sidewalls of the silicon wells beneath each pixel.

  2. A Novel Micro- and Nano-Scale Positioning Sensor Based on Radio Frequency Resonant Cavities

    PubMed Central

    Asua, Estibaliz; Etxebarria, Victor; García-Arribas, Alfredo; Feutchwanger, Jorge; Portilla, Joaquín; Lucas, Julio

    2014-01-01

    In many micro- and nano-scale technological applications high sensitivity displacement sensors are needed, especially in ultraprecision metrology and manufacturing. In this work a new way of sensing displacement based on radio frequency resonant cavities is presented and experimentally demonstrated using a first laboratory prototype. The principle of operation of the new transducer is summarized and tested. Furthermore, an electronic interface that can be used together with the displacement transducer is designed and proved. It has been experimentally demonstrated that very high and linear sensitivity characteristic curves, in the range of some kHz/nm; are easily obtainable using this kind of transducer when it is combined with a laboratory network analyzer. In order to replace a network analyzer and provide a more affordable, self-contained, compact solution, an electronic interface has been designed, preserving as much as possible the excellent performance of the transducer, and turning it into a true standalone positioning sensor. The results obtained using the transducer together with a first prototype of the electronic interface built with cheap discrete elements show that positioning accuracies in the micrometer range are obtainable using this cost-effective solution. Better accuracies would also be attainable but using more involved and costly electronics interfaces. PMID:24887041

  3. Micro-swimming without flagella: Propulsion by internal structures

    NASA Astrophysics Data System (ADS)

    Ehlers, Kurt M.; Koiller, Jair

    2011-12-01

    Since a first proof-of-concept for an autonomous micro-swimming device appeared in 2005 a strong interest on the subject ensued. The most common configuration consists of a cell driven by an external propeller, bio-inspired by bacteria such as E.coli. It is natural to investigate whether micro-robots powered by internal mechanisms could be competitive. We compute the translational and rotational velocity of a spheroid that produces a helical wave on its surface, as has been suggested for the rod-shaped cyanobacterium Synechococcus. This organisms swims up to ten body lengths per second without external flagella. For the mathematical analysis we employ the tangent plane approximation method, which is adequate for amplitudes, frequencies and wave lengths considered here. We also present a qualitative discussion about the efficiency of a device driven by an internal rotating structure.

  4. A wireless laser displacement sensor node for structural health monitoring.

    PubMed

    Park, Hyo Seon; Kim, Jong Moon; Choi, Se Woon; Kim, Yousok

    2013-09-30

    This study describes a wireless laser displacement sensor node that measures displacement as a representative damage index for structural health monitoring (SHM). The proposed measurement system consists of a laser displacement sensor (LDS) and a customized wireless sensor node. Wireless communication is enabled by a sensor node that consists of a sensor module, a code division multiple access (CDMA) communication module, a processor, and a power module. An LDS with a long measurement distance is chosen to increase field applicability. For a wireless sensor node driven by a battery, we use a power control module with a low-power processor, which facilitates switching between the sleep and active modes, thus maximizing the power consumption efficiency during non-measurement and non-transfer periods. The CDMA mode is also used to overcome the limitation of communication distance, which is a challenge for wireless sensor networks and wireless communication. To evaluate the reliability and field applicability of the proposed wireless displacement measurement system, the system is tested onsite to obtain the required vertical displacement measurements during the construction of mega-trusses and an edge truss, which are the primary structural members in a large-scale irregular building currently under construction. The measurement values confirm the validity of the proposed wireless displacement measurement system and its potential for use in safety evaluations of structural elements.

  5. A Wireless Laser Displacement Sensor Node for Structural Health Monitoring

    PubMed Central

    Park, Hyo Seon; Kim, Jong Moon; Choi, Se Woon; Kim, Yousok

    2013-01-01

    This study describes a wireless laser displacement sensor node that measures displacement as a representative damage index for structural health monitoring (SHM). The proposed measurement system consists of a laser displacement sensor (LDS) and a customized wireless sensor node. Wireless communication is enabled by a sensor node that consists of a sensor module, a code division multiple access (CDMA) communication module, a processor, and a power module. An LDS with a long measurement distance is chosen to increase field applicability. For a wireless sensor node driven by a battery, we use a power control module with a low-power processor, which facilitates switching between the sleep and active modes, thus maximizing the power consumption efficiency during non-measurement and non-transfer periods. The CDMA mode is also used to overcome the limitation of communication distance, which is a challenge for wireless sensor networks and wireless communication. To evaluate the reliability and field applicability of the proposed wireless displacement measurement system, the system is tested onsite to obtain the required vertical displacement measurements during the construction of mega-trusses and an edge truss, which are the primary structural members in a large-scale irregular building currently under construction. The measurement values confirm the validity of the proposed wireless displacement measurement system and its potential for use in safety evaluations of structural elements. PMID:24084114

  6. Efficient placement of structural dynamics sensors on the space station

    NASA Technical Reports Server (NTRS)

    Lepanto, Janet A.; Shepard, G. Dudley

    1987-01-01

    System identification of the space station dynamic model will require flight data from a finite number of judiciously placed sensors on it. The placement of structural dynamics sensors on the space station is a particularly challenging problem because the station will not be deployed in a single mission. Given that the build-up sequence and the final configuration for the space station are currently undetermined, a procedure for sensor placement was developed using the assembly flights 1 to 7 of the rephased dual keel space station as an example. The procedure presented approaches the problem of placing the sensors from an engineering, as opposed to a mathematical, point of view. In addition to locating a finite number of sensors, the procedure addresses the issues of unobserved structural modes, dominant structural modes, and the trade-offs involved in sensor placement for space station. This procedure for sensor placement will be applied to revised, and potentially more detailed, finite element models of the space station configuration and assembly sequence.

  7. Photocatalytically Renewable Micro-electrochemical Sensor for Real-Time Monitoring of Cells.

    PubMed

    Xu, Jia-Quan; Liu, Yan-Ling; Wang, Qian; Duo, Huan-Huan; Zhang, Xin-Wei; Li, Yu-Tao; Huang, Wei-Hua

    2015-11-23

    Electrode fouling and passivation is a substantial and inevitable limitation in electrochemical biosensing, and it is a great challenge to efficiently remove the contaminant without changing the surface structure and electrochemical performance. Herein, we propose a versatile and efficient strategy based on photocatalytic cleaning to construct renewable electrochemical sensors for cell analysis. This kind of sensor was fabricated by controllable assembly of reduced graphene oxide (RGO) and TiO2 to form a sandwiching RGO@TiO2 structure, followed by deposition of Au nanoparticles (NPs) onto the RGO shell. The Au NPs-RGO composite shell provides high electrochemical performance. Meanwhile, the encapsulated TiO2 ensures an excellent photocatalytic cleaning property. Application of this renewable microsensor for detection of nitric oxide (NO) release from cells demonstrates the great potential of this strategy in electrode regeneration and biosensing.

  8. Fiber optic sensors for structural health monitoring of air platforms.

    PubMed

    Guo, Honglei; Xiao, Gaozhi; Mrad, Nezih; Yao, Jianping

    2011-01-01

    Aircraft operators are faced with increasing requirements to extend the service life of air platforms beyond their designed life cycles, resulting in heavy maintenance and inspection burdens as well as economic pressure. Structural health monitoring (SHM) based on advanced sensor technology is potentially a cost-effective approach to meet operational requirements, and to reduce maintenance costs. Fiber optic sensor technology is being developed to provide existing and future aircrafts with SHM capability due to its unique superior characteristics. This review paper covers the aerospace SHM requirements and an overview of the fiber optic sensor technologies. In particular, fiber Bragg grating (FBG) sensor technology is evaluated as the most promising tool for load monitoring and damage detection, the two critical SHM aspects of air platforms. At last, recommendations on the implementation and integration of FBG sensors into an SHM system are provided.

  9. Microwave Sensor for Blade Tip Clearance and Structural Health Measurements

    NASA Technical Reports Server (NTRS)

    Woike, Mark R.; Bencic, Timothy J.

    2008-01-01

    The use of microwave based sensors for the health monitoring of rotating machinery is being explored at the NASA Glenn Research Center. The microwave sensor works on the principle of sending a continuous signal towards a rotating component and measuring the reflected signal. The phase shift of the reflected signal is proportional to the distance between the sensor and the component that is being measured. This type of sensor is beneficial in that it has the ability to operate at extremely high temperatures and is unaffected by contaminants that may be present in the rotating machinery. It is intended to use these probes in the hot sections of turbine engines for closed loop turbine clearance control and structural health measurements. Background on the sensors, an overview of their calibration and preliminary results from using them to make blade tip clearance and health measurements on a large axial vane fan will be presented.

  10. Fiber Optic Sensors for Structural Health Monitoring of Air Platforms

    PubMed Central

    Guo, Honglei; Xiao, Gaozhi; Mrad, Nezih; Yao, Jianping

    2011-01-01

    Aircraft operators are faced with increasing requirements to extend the service life of air platforms beyond their designed life cycles, resulting in heavy maintenance and inspection burdens as well as economic pressure. Structural health monitoring (SHM) based on advanced sensor technology is potentially a cost-effective approach to meet operational requirements, and to reduce maintenance costs. Fiber optic sensor technology is being developed to provide existing and future aircrafts with SHM capability due to its unique superior characteristics. This review paper covers the aerospace SHM requirements and an overview of the fiber optic sensor technologies. In particular, fiber Bragg grating (FBG) sensor technology is evaluated as the most promising tool for load monitoring and damage detection, the two critical SHM aspects of air platforms. At last, recommendations on the implementation and integration of FBG sensors into an SHM system are provided. PMID:22163816

  11. Fiber optic sensors for structural health monitoring of air platforms.

    PubMed

    Guo, Honglei; Xiao, Gaozhi; Mrad, Nezih; Yao, Jianping

    2011-01-01

    Aircraft operators are faced with increasing requirements to extend the service life of air platforms beyond their designed life cycles, resulting in heavy maintenance and inspection burdens as well as economic pressure. Structural health monitoring (SHM) based on advanced sensor technology is potentially a cost-effective approach to meet operational requirements, and to reduce maintenance costs. Fiber optic sensor technology is being developed to provide existing and future aircrafts with SHM capability due to its unique superior characteristics. This review paper covers the aerospace SHM requirements and an overview of the fiber optic sensor technologies. In particular, fiber Bragg grating (FBG) sensor technology is evaluated as the most promising tool for load monitoring and damage detection, the two critical SHM aspects of air platforms. At last, recommendations on the implementation and integration of FBG sensors into an SHM system are provided. PMID:22163816

  12. Wireless Zigbee strain gage sensor system for structural health monitoring

    NASA Astrophysics Data System (ADS)

    Ide, Hiroshi; Abdi, Frank; Miraj, Rashid; Dang, Chau; Takahashi, Tatsuya; Sauer, Bruce

    2009-05-01

    A compact cell phone size radio frequency (ZigBee) wireless strain measurement sensor system to measure the structural strain deformation was developed. The developed system provides an accurate strain measurement data stream to the Internet for further Diagnostic and Prognostic (DPS) correlation. Existing methods of structural measurement by strain sensors (gauges) do not completely satisfy problems posed by continuous structural health monitoring. The need for efficient health monitoring methods with real-time requirements to bidirectional data flow from sensors and to a commanding device is becoming critical for keeping our daily life safety. The use of full-field strain measurement techniques could reduce costly experimental programs through better understanding of material behavior. Wireless sensor-network technology is a monitoring method that is estimated to grow rapidly providing potential for cost savings over traditional wired sensors. The many of currently available wireless monitoring methods have: the proactive and constant data rate character of the data streams rather than traditional reactive, event-driven data delivery; mostly static node placement on structures with limited number of nodes. Alpha STAR Electronics' wireless sensor network system, ASWN, addresses some of these deficiencies, making the system easier to operate. The ASWN strain measurement system utilizes off-the-shelf sensors, namely strain gauges, with an analog-to-digital converter/amplifier and ZigBee radio chips to keep cost lower. Strain data is captured by the sensor, converted to digital form and delivered to the ZigBee radio chip, which in turn broadcasts the information using wireless protocols to a Personal Data Assistant (PDA) or Laptop/Desktop computers. From here, data is forwarded to remote computers for higher-level analysis and feedback using traditional cellular and satellite communication or the Ethernet infrastructure. This system offers a compact size, lower cost

  13. Porous media modeling and micro-structurally motivated material moduli determination via the micro-dilatation theory

    NASA Astrophysics Data System (ADS)

    Jeong, J.; Ramézani, H.; Sardini, P.; Kondo, D.; Ponson, L.; Siitari-Kauppi, M.

    2015-07-01

    In the present contribution, the porous material modeling and micro-structural material parameters determination are scrutinized via the micro-dilatation theory. The main goal is to take advantage of the micro-dilatation theory which belongs to the generalized continuum media. In the first stage, the thermodynamic laws are entirely revised to reach the energy balance relation using three variables, deformation, porosity change and its gradient underlying the porous media as described in the micro-dilatation theory or so-called void elasticity. Two experiments over cement mortar specimens are performed in order to highlight the material parameters related to the pore structure. The shrinkage due to CO2 carbonation, porosity and its gradient are calculated. The extracted values are verified via 14C-PMMA radiographic image method. The modeling of swelling phenomenon of Delayed Ettringite Formation (DEF) is studied later on. This issue is performed via the crystallization pressure application using the micro-dilatation theory.

  14. SVAS3: Strain Vector Aided Sensorization of Soft Structures

    PubMed Central

    Culha, Utku; Nurzaman, Surya G.; Clemens, Frank; Iida, Fumiya

    2014-01-01

    Soft material structures exhibit high deformability and conformability which can be useful for many engineering applications such as robots adapting to unstructured and dynamic environments. However, the fact that they have almost infinite degrees of freedom challenges conventional sensory systems and sensorization approaches due to the difficulties in adapting to soft structure deformations. In this paper, we address this challenge by proposing a novel method which designs flexible sensor morphologies to sense soft material deformations by using a functional material called conductive thermoplastic elastomer (CTPE). This model-based design method, called Strain Vector Aided Sensorization of Soft Structures (SVAS3), provides a simulation platform which analyzes soft body deformations and automatically finds suitable locations for CTPE-based strain gauge sensors to gather strain information which best characterizes the deformation. Our chosen sensor material CTPE exhibits a set of unique behaviors in terms of strain length electrical conductivity, elasticity, and shape adaptability, allowing us to flexibly design sensor morphology that can best capture strain distributions in a given soft structure. We evaluate the performance of our approach by both simulated and real-world experiments and discuss the potential and limitations. PMID:25036332

  15. A Vision-Based Sensor for Noncontact Structural Displacement Measurement

    PubMed Central

    Feng, Dongming; Feng, Maria Q.; Ozer, Ekin; Fukuda, Yoshio

    2015-01-01

    Conventional displacement sensors have limitations in practical applications. This paper develops a vision sensor system for remote measurement of structural displacements. An advanced template matching algorithm, referred to as the upsampled cross correlation, is adopted and further developed into a software package for real-time displacement extraction from video images. By simply adjusting the upsampling factor, better subpixel resolution can be easily achieved to improve the measurement accuracy. The performance of the vision sensor is first evaluated through a laboratory shaking table test of a frame structure, in which the displacements at all the floors are measured by using one camera to track either high-contrast artificial targets or low-contrast natural targets on the structural surface such as bolts and nuts. Satisfactory agreements are observed between the displacements measured by the single camera and those measured by high-performance laser displacement sensors. Then field tests are carried out on a railway bridge and a pedestrian bridge, through which the accuracy of the vision sensor in both time and frequency domains is further confirmed in realistic field environments. Significant advantages of the noncontact vision sensor include its low cost, ease of operation, and flexibility to extract structural displacement at any point from a single measurement. PMID:26184197

  16. Early-age monitoring of cement structures using FBG sensors

    NASA Astrophysics Data System (ADS)

    Wang, Chuan; Zhou, Zhi; Zhang, Zhichun; Ou, Jinping

    2006-03-01

    With more and more broad applications of the cement-based structures such as neat cement paste, cement mortar and concrete in civil engineering, people hope to find out what their performances should like. The in-service performances of cement-based structures are highly affected by their hardening process during the early-age. But it is still a big problem for traditional sensors to be used to monitor the early curing of cement-based structures due to such disadvantages as difficulties to install sensors inside the concrete, limited measuring points, poor durability and interference of electromagnetic wave and so on. In this paper, according to the sensing properties of the Fiber Bragg Grating sensors and self-characters of the cement-based structures, we have successfully finished measuring and monitoring the early-age inner-strain and temperature changes of the neat cement paste, concrete with and without restrictions, mass concrete structures and negative concrete, respectively. Three types of FBG-based sensors have been developed to monitor the cement-based structures. Besides, the installation techniques and the embedding requirements of FBG sensors in cement-based structures are also discussed. Moreover, such kind of technique has been used in practical structure, 3rd Nanjing Yangtze Bridge, and the results show that FBG sensors are well proper for measuring and monitoring the temperature and strain changes including self-shrinkage, dry shrinkage, plastic shrinkage, temperature expansion, frost heaving and so on inside different cement-based structures. This technique provides us a new useful measuring method on early curing monitoring of cement-based structures and greater understanding of details of their hardening process.

  17. Spiral Passive Electromagnetic Sensor (SPES) for composite structural changes in aircraft structures

    NASA Astrophysics Data System (ADS)

    Iervolino, Onorio; Meo, Michele

    2016-04-01

    A major goal of structural health monitoring (SHM) is to provide accurate and responsive detection and monitoring of flaws. This research work reports an investigation of SPES sensors for damage detection, investigating different sensor sizes and how they affect the sensor's signal. A sensor able to monitor structural change that can be remotely interrogated and does not need a power supply is presented in this work. The SPES-sensor presents the great advantage of monitoring conductive and non-conductive structures such as fiberglass-reinforced composites (FRC) and carbon fiber-reinforced polymers (CFRP). Any phenomena that affect the magnetic field of the SPES can be detected and monitored. A study was conducted to investigate the capability of sensor to give information on structural changes, simulated by the presence of an external mass placed in the proximity of sensor. Effect of different positions of the SPES within the sample, and how to extend the area of inspection using multiple sensors was investigated. The sensor was tested embedded in the samples, simulating the structural change on both sides of the sample. In both configurations the sensor described herein demonstrated a great potential to monitor structural changes.

  18. Fiber optic sensors for evaluation and monitoring of civil structures

    NASA Astrophysics Data System (ADS)

    Huston, Dryver R.; Fuhr, Peter L.; Udd, Eric; Inaudi, Daniele

    1999-12-01

    This paper gives an overview of the primary issues of structural health and evaluation monitoring for civil structures, such as bridges, dams, buildings and roadways, and role that fiber optic sensors play in the monitoring efforts. Some of the quantities that need to be measured are displacement, velocity, acceleration, jerk, force, stress, strain, temperature, fracture, moisture, fatigue, and chemical state, i.e. corrosion. Fiber optic sensors have the capability to measure most, if not all, of these quantities. Fiber optic sensors exploit a variety of physical principles through which physical quantities are measured. The particular types of fiber sensors that will be discussed in this paper are: intensity-based, modal domain interferometric, Bragg grating, white light interferometric, and Brillouin backscatter. The operating principles and application results from field and laboratory studies are presented.

  19. A Novel Method for In-Situ Monitoring of Local Voltage, Temperature and Humidity Distributions in Fuel Cells Using Flexible Multi-Functional Micro Sensors

    PubMed Central

    Lee, Chi-Yuan; Fan, Wei-Yuan; Chang, Chih-Ping

    2011-01-01

    In this investigation, micro voltage, temperature and humidity sensors were fabricated and integrated for the first time on a stainless steel foil using micro-electro-mechanical systems (MEMS). These flexible multi-functional micro sensors have the advantages of high temperature resistance, flexibility, smallness, high sensitivity and precision of location. They were embedded in a proton exchange membrane fuel cell (PEMFC) and used to simultaneously measure variations in the inner voltage, temperature and humidity. The accuracy and reproducibility of the calibrated results obtained using the proposed micro sensors is excellent. The experimental results indicate that, at high current density and 100%RH or 75%RH, the relative humidity midstream and downstream saturates due to severe flooding. The performance of the PEM fuel cell can be stabilized using home-made flexible multi-functional micro sensors by the in-situ monitoring of local voltage, temperature and humidity distributions within it. PMID:22319361

  20. Diagnosis and sensor validation through knowledge of structure and function

    NASA Technical Reports Server (NTRS)

    Scarl, Ethan A.; Jamieson, John R.; Delaune, Carl I.

    1987-01-01

    The liquid oxygen expert system 'LES' is proposed as the first capable of diagnostic reasoning from sensor data, using model-based knowledge of structure and function to find the expected state of all system objects, including sensors. The approach is generally algorithmic rather than heuristic, and represents uncertainties as sets of possibilities. Functional relationships are inverted to determine hypothetical values for potentially faulty objects, and may include conditional functions not normally considered to have inverses.

  1. Integrating optical glucose sensing into a planar waveguide sensor structure

    NASA Astrophysics Data System (ADS)

    Dutta, Aradhana; Deka, Bidyut; Sahu, Partha P.

    2013-06-01

    A device for glucose monitoring in people with diabetes is a clinical and research priority in the recent years for its accurate self management. An extensive theoretical design and development of an optical sensor is carried out incorporating planar waveguide structure in an endeavor to measure slight changes of glucose concentration. The sensor is simple and highly sensitive and has the potential to be used for online monitoring of blood glucose levels for the diabetic patients in the near future.

  2. Optical Fiber Sensors for Aircraft Structural Health Monitoring.

    PubMed

    García, Iker; Zubia, Joseba; Durana, Gaizka; Aldabaldetreku, Gotzon; Illarramendi, María Asunción; Villatoro, Joel

    2015-06-30

    Aircraft structures require periodic and scheduled inspection and maintenance operations due to their special operating conditions and the principles of design employed to develop them. Therefore, structural health monitoring has a great potential to reduce the costs related to these operations. Optical fiber sensors applied to the monitoring of aircraft structures provide some advantages over traditional sensors. Several practical applications for structures and engines we have been working on are reported in this article. Fiber Bragg gratings have been analyzed in detail, because they have proved to constitute the most promising technology in this field, and two different alternatives for strain measurements are also described. With regard to engine condition evaluation, we present some results obtained with a reflected intensity-modulated optical fiber sensor for tip clearance and tip timing measurements in a turbine assembled in a wind tunnel.

  3. Optical Fiber Sensors for Aircraft Structural Health Monitoring

    PubMed Central

    García, Iker; Zubia, Joseba; Durana, Gaizka; Aldabaldetreku, Gotzon; Illarramendi, María Asunción; Villatoro, Joel

    2015-01-01

    Aircraft structures require periodic and scheduled inspection and maintenance operations due to their special operating conditions and the principles of design employed to develop them. Therefore, structural health monitoring has a great potential to reduce the costs related to these operations. Optical fiber sensors applied to the monitoring of aircraft structures provide some advantages over traditional sensors. Several practical applications for structures and engines we have been working on are reported in this article. Fiber Bragg gratings have been analyzed in detail, because they have proved to constitute the most promising technology in this field, and two different alternatives for strain measurements are also described. With regard to engine condition evaluation, we present some results obtained with a reflected intensity-modulated optical fiber sensor for tip clearance and tip timing measurements in a turbine assembled in a wind tunnel. PMID:26134107

  4. Nano-structured surface plasmon resonance sensor for sensitivity enhancement

    NASA Astrophysics Data System (ADS)

    Kim, Jae-Ho; Kim, Hyo-Sop; Kim, Jin-Ho; Choi, Sung-Wook; Cho, Yong-Jin

    2008-08-01

    A new nano-structured SPR sensor was devised to improve its sensitivity. Nano-scaled silica particles were used as the template to fabricate nano-structure. The surface of the silica particles was modified with thiol group and a single layer of the modified silica particles was attached on the gold or silver thin film using Langmuir-Blodgett (LB) method. Thereafter, gold or silver was coated on the template by an e-beam evaporator. Finally, the nano-structured surface with basin-like shape was obtained after removing the silica particles by sonication. Applying the new developed SPR sensor to a model food of alcoholic beverage, the sensitivities for the gold and silver nano-structured sensors, respectively, had 95% and 126% higher than the conventional one.

  5. Optical Fiber Sensors for Aircraft Structural Health Monitoring.

    PubMed

    García, Iker; Zubia, Joseba; Durana, Gaizka; Aldabaldetreku, Gotzon; Illarramendi, María Asunción; Villatoro, Joel

    2015-01-01

    Aircraft structures require periodic and scheduled inspection and maintenance operations due to their special operating conditions and the principles of design employed to develop them. Therefore, structural health monitoring has a great potential to reduce the costs related to these operations. Optical fiber sensors applied to the monitoring of aircraft structures provide some advantages over traditional sensors. Several practical applications for structures and engines we have been working on are reported in this article. Fiber Bragg gratings have been analyzed in detail, because they have proved to constitute the most promising technology in this field, and two different alternatives for strain measurements are also described. With regard to engine condition evaluation, we present some results obtained with a reflected intensity-modulated optical fiber sensor for tip clearance and tip timing measurements in a turbine assembled in a wind tunnel. PMID:26134107

  6. Molecular structure and thermodynamic predictions to create highly sensitive microRNA biosensors.

    PubMed

    Larkey, Nicholas E; Brucks, Corinne N; Lansing, Shan S; Le, Sophia D; Smith, Natasha M; Tran, Victoria; Zhang, Lulu; Burrows, Sean M

    2016-02-25

    Many studies have established microRNAs (miRNAs) as post-transcriptional regulators in a variety of intracellular molecular processes. Abnormal changes in miRNA have been associated with several diseases. However, these changes are sometimes subtle and occur at nanomolar levels or lower. Several biosensing hurdles for in situ cellular/tissue analysis of miRNA limit detection of small amounts of miRNA. Of these limitations the most challenging are selectivity and sensor degradation creating high background signals and false signals. Recently we developed a reporter+probe biosensor for let-7a that showed potential to mitigate false signal from sensor degradation. Here we designed reporter+probe biosensors for miR-26a-2-3p and miR-27a-5p to better understand the effect of thermodynamics and molecular structures of the biosensor constituents on the analytical performance. Signal changes from interactions between Cy3 and Cy5 on the reporters were used to understand structural aspects of the reporter designs. Theoretical thermodynamic values, single stranded conformations, hetero- and homodimerization structures, and equilibrium concentrations of the reporters and probes were used to interpret the experimental observations. Studies of the sensitivity and selectivity revealed 5-9 nM detection limits in the presence and absence of interfering off-analyte miRNAs. These studies will aid in determining how to rationally design reporter+probe biosensors to overcome hurdles associated with highly sensitive miRNA biosensing.

  7. Structure of Palladium Nanoclusters for Hydrogen Gas Sensors

    SciTech Connect

    Stevens, K.J.; Ingham, B.; Toney, M.F.; Brown, S.A.; Lassesson, A.; /SLAC, SSRL /Canterbury U.

    2009-05-11

    Palladium nanoclusters produced by inert gas aggregation/magnetron sputtering are used as building blocks for the construction of nano electronic devices with large surface to volume ratios that can be used as sensitive hydrogen gas sensors in fuel cells and in petrochemical plants. X-ray diffraction (XRD), extended X-ray absorption fine structure (EXAFS), and high resolution transmission electron microscopy (HRTEM) have been used to characterize the structure, lattice constant, particle diameter and oxide thickness of the palladium nanoclusters in order to understand the operation of these sensors. Grazing incidence XRD (GIXRD) of heat treated Pd clusters has shown that the palladanite structure forms at elevated temperatures.

  8. Optimal Sensor Locations for Structural Identification

    NASA Technical Reports Server (NTRS)

    Udwadia, F. E.; Garba, J.

    1985-01-01

    The optimum sensor location problem, OSLP, may be thought of in terms of the set of systems, S, the class of input time functions, I, and the identification algorithm (estimator) used, E. Thus, for a given time history of input, the technique of determining the OSL requires, in general, the solution of the optimization and the identification problems simultaneously. A technique which uncouples the two problems is introduced. This is done by means of the concept of an efficient estimator for which the covariance of the parameter estimates is inversely proportional to the Fisher Information Matrix.

  9. Experimental and numerical analysis of a hybrid FBG long gauge sensor for structural health monitoring

    NASA Astrophysics Data System (ADS)

    Torres Górriz, Benjamín; Calderón García, Pedro; Payá-Zaforteza, Ignacio J.; Sales Maicas, Salvador

    2014-12-01

    This paper presents a new long gauge sensor for structural health monitoring based on the use of fiber Bragg gratings. The proposed sensor has the advantage over existing sensors that it does not require prestressing of the optical fiber. The development consisted of numerical studies complemented by experimental tests to analyze: (1) the strain transfer between the sensor and the host structure; (2) the influence of sensor axial stiffness on the structural behavior of the host structure; (3) the influence of the mechanical properties of the adhesive used to fix the sensor and (4) the failure modes of the sensor (buckling and shear stress of sensor anchors).

  10. Development and installation of Picostrain sensors in structural systems

    NASA Astrophysics Data System (ADS)

    Sener, Joseph C.; Latta, Bernard M.; Ross, Jimmy D.

    2004-07-01

    The concept of the Picostrain sensor technology is based on a standard, commercially available, electrical cable assembly embedded in pavement or structural members. The concept has been developed through the 1990s and patented by the Idaho Transportation Department (ITD) in 2003. The objective of this new technology is to build an inexpensive, easily installed and maintained sensor system for the purposes of vehicle classification (VC), vehicle identification (VI), weigh-in-motion (WIM), and vehicle tracking (VT) applications along with real-time monitoring and evaluation of structural performance under static and dynamic traffic loading. It is intended, in the future, that these sensors will be further developed to replace curently utilized expensive embedded pavement and structural sensors for ultimate improvement of transportation decision-making and planning. This will also help to document the movement of people and goods along with the evironmental, social, economic and financial parameters with an emphasis on tracking movements in social life for security based upon the use of this durable and reliable transducers. Approximately, 400 sensors have been installed on and in the reinforced concrete structural members of the West Park Center River Crossing Bridge (Bridge) and the Micron Engineering Center (MEC) building (Building) at Boise State University (BSU) in Boise, Idaho, USA, since 1998. These sensors were installed: in bridge pile caps, piers, girders and decks; bridge abutment embankments; building footings, columns, beams, floor slabs; and, have been linked to instrument cabinets on site. These sensors installed structures may now be called "smart" structures since they contain a resident sensing system capable of maintaining a constant watch over the integrity of the structure. These sensing systems will be able to evaluate the applied loads, as well as the static and dynamic response of the structure. This paper introduces and describes the new

  11. Three Dimensional Visualization of Vibration of Civil Structure with Multisite Wireless Sensor Nodes

    NASA Astrophysics Data System (ADS)

    Takamoto, Tatsunao; Yamaguchi, Masayoshi; Nakahata, Kazuyuki; Ohga, Mitao

    The acceleration sensors which adopt the MEMS (Micro Electro Mechanical System) technology, offer high reliability and sensitivity in a small size. Using the MEMS sensor, we develop a visualization system of vibration of a civil structure at a low cost. In our system, time series of acceleration data measured at multiple points are transmitted to a computer at base-station with the wireless LAN and then converted to displacement data by the linear acceleration method. Here we make a digital filter to avoid a drift of the baseline of displacement data and to eliminate the white noise. First, our measurement setup and data conversion from acceleration to displacement using digital filters are described. Next we show an animation of vibration of a connecting bridge between two buildings by means of triaxial displacement data.

  12. Structural integrated sensor and actuator systems for active flow control

    NASA Astrophysics Data System (ADS)

    Behr, Christian; Schwerter, Martin; Leester-Schädel, Monika; Wierach, Peter; Dietzel, Andreas; Sinapius, Michael

    2016-04-01

    An adaptive flow separation control system is designed and implemented as an essential part of a novel high-lift device for future aircraft. The system consists of MEMS pressure sensors to determine the flow conditions and adaptive lips to regulate the mass flow and the velocity of a wall near stream over the internally blown Coanda flap. By the oscillating lip the mass flow in the blowing slot changes dynamically, consequently the momentum exchange of the boundary layer over a high lift flap required mass flow can be reduced. These new compact and highly integrated systems provide a real-time monitoring and manipulation of the flow conditions. In this context the integration of pressure sensors into flow sensing airfoils of composite material is investigated. Mechanical and electrical properties of the integrated sensors are investigated under mechanical loads during tensile tests. The sensors contain a reference pressure chamber isolated to the ambient by a deformable membrane with integrated piezoresistors connected as a Wheatstone bridge, which outputs voltage signals depending on the ambient pressure. The composite material in which the sensors are embedded consists of 22 individual layers of unidirectional glass fiber reinforced plastic (GFRP) prepreg. The results of the experiments are used for adapting the design of the sensors and the layout of the laminate to ensure an optimized flux of force in highly loaded structures primarily for future aeronautical applications. It can be shown that the pressure sensor withstands the embedding process into fiber composites with full functional capability and predictable behavior under stress.

  13. Surface biofunctionalization and production of miniaturized sensor structures using aerosol printing technologies.

    PubMed

    Grunwald, Ingo; Groth, Esther; Wirth, Ingo; Schumacher, Julian; Maiwald, Marcus; Zoellmer, Volker; Busse, Matthias

    2010-03-01

    The work described in this paper demonstrates that very small protein and DNA structures can be applied to various substrates without denaturation using aerosol printing technology. This technology allows high-resolution deposition of various nanoscaled metal and biological suspensions. Before printing, metal and biological suspensions were formulated and then nebulized to form an aerosol which is aerodynamically focused on the printing module of the system in order to achieve precise structuring of the nanoscale material on a substrate. In this way, it is possible to focus the aerosol stream at a distance of about 5 mm from the printhead to the surface. This technology is useful for printing fluorescence-marked proteins and printing enzymes without affecting their biological activity. Furthermore, higher molecular weight DNA can be printed without shearing. The advantages, such as printing on complex, non-planar 3D structured surfaces, and disadvantages of the aerosol printing technology are also discussed and are compared with other printing technologies. In addition, miniaturized sensor structures with line thicknesses in the range of a few micrometers are fabricated by applying a silver sensor structure to glass. After sintering using an integrated laser or in an oven process, electrical conductivity is achieved within the sensor structure. Finally, we printed BSA in small micrometre-sized areas within the sensor structure using the same deposition system. The aerosol printing technology combined with material development offers great advantages for future-oriented applications involving biological surface functionalization on small areas. This is important for innovative biomedical micro-device development and for production solutions which bridge the disciplines of biology and electronics. PMID:20811121

  14. Cooperative Micro-Motion and Structural Rearrangement of Dusty Plasma Liquids with Micro-Heterogeneity

    NASA Astrophysics Data System (ADS)

    Yang, Chi; Su, Yen-Shuo; I, Lin

    Microscopically, the liquid around the freezing point is not completely disordered. Structurally, it can be viewed as a heterogeneous patchwork of solid like crystalline ordered domains (CODs) coexisting with defect clusters, which can be rearrangedby weak thermal perturbation. In this work, using a quenched dusty plasma liquid as a platform, we briefly report our recent works on the cooperative micro-motion/structural rearrangement (SR) and finding the effective alarms for predicting structural rearrangement. The cooperative motion are classified into static patches with cage rattling, drifting patches, rotating patches, 1D hopping strings, and shear strips. The rotation of a large COD is achieved through rupturing it into several smaller CODs rotating along the same direction with a small angle, and healing back to a large COD. They are also responsible for rotating large adjacent CODs and merging into a single large COD. The temporal evolution of the fraction of fast rotating bonds exhibits intermittent type fluctuations and is highly correlated with the fluctuation of the structural order. For the short term SR prediction, the small bond orientational order (BOO) is a useful alarm. For sorting out the short term SR for the ordered site with large BOO, the deviation of the local BOO from the coarse grained BOO over nearest neighbors serves as an effective second alarm.

  15. Carbon Nanotube-Based Structural Health Monitoring Sensors

    NASA Technical Reports Server (NTRS)

    Wincheski, Russell; Jordan, Jeffrey; Oglesby, Donald; Watkins, Anthony; Patry, JoAnne; Smits, Jan; Williams, Phillip

    2011-01-01

    Carbon nanotube (CNT)-based sensors for structural health monitoring (SHM) can be embedded in structures of all geometries to monitor conditions both inside and at the surface of the structure to continuously sense changes. These CNTs can be manipulated into specific orientations to create small, powerful, and flexible sensors. One of the sensors is a highly flexible sensor for crack growth detection and strain field mapping that features a very dense and highly ordered array of single-walled CNTs. CNT structural health sensors can be mass-produced, are inexpensive, can be packaged in small sizes (0.5 micron(sup 2)), require less power than electronic or piezoelectric transducers, and produce less waste heat per square centimeter than electronic or piezoelectric transducers. Chemically functionalized lithographic patterns are used to deposit and align the CNTs onto metallic electrodes. This method consistently produces aligned CNTs in the defined locations. Using photo- and electron-beam lithography, simple Cr/Au thin-film circuits are patterned onto oxidized silicon substrates. The samples are then re-patterned with a CNT-attracting, self-assembled monolayer of 3-aminopropyltriethoxysilane (APTES) to delineate the desired CNT locations between electrodes. During the deposition of the solution-suspended single- wall CNTs, the application of an electric field to the metallic contacts causes alignment of the CNTs along the field direction. This innovation is a prime candidate for smart skin technologies with applications ranging from military, to aerospace, to private industry.

  16. Micro Extrinsic Fiber-Optic Fabry-Perot Interferometric Sensor Based on Erbium- and Boron-Doped Fibers

    NASA Astrophysics Data System (ADS)

    Rao, Yun-Jiang; Xu, Bing; Ran, Zeng-Ling; Gong, Yuan

    2010-02-01

    Micro extrinsic Fabry-Perot interferometers (MEFPIs), with cavity lengths of up to ~ 9 μm and maximum fringe contrast of ~ 19 dB, are fabricated by chemically etching Er- and B-doped optical fibers and then splicing the etched fiber to a single-mode fiber, for the first time to the best of our knowledge. The strain and temperature responses of the MEFPI sensors are investigated experimentally. Good linearity and high sensitivity are achieved. Such a type of MEFPI sensor is cost-effective and suitable for mass production, indicating its great potential for a wide range of applications.

  17. Bio-inspired sensor skins for structural health monitoring

    NASA Astrophysics Data System (ADS)

    Tata, Uday; Deshmukh, S.; Chiao, J. C.; Carter, Ronald; Huang, H.

    2009-10-01

    This paper presents the simulation and experimental work that proved the feasibility of using a patch antenna for strain measurement. A patch antenna, besides serving as a data transmitting device, can function as a transducer that directly encodes the strain experienced into its resonant frequency. Printed on a flexible substrate, the antenna sensor is small in size, has a low profile and can be conformal to any attached surface. The technique for interrogating the antenna sensor using a wireless non-contact method is also demonstrated. Without needing electric wiring for power supply and data transmitting, the antenna sensor has a great potential for the realization of engineered sensor skins that imitate the sense of pain for structural health monitoring purposes.

  18. Micro/nanoscale continuous printing: direct-writing of wavy micro/nano structures via electrospinning

    NASA Astrophysics Data System (ADS)

    Fang, Feiyu; Du, Zefeng; Zeng, Jun; Zhu, Ziming; Chen, Xin; Chen, Xindu; Lv, Yuanjun; Wang, Han

    2015-07-01

    Micro/nanofibers that are created by direct-writing using an electrospinning (ES) technique have aroused much recent attention, owing to their intriguing physical properties and great potential as building blocks for micro/nanoscale devices. In this work, a wavy direct-writing (WDW) process was developed to directly write wavy micro/nanostructures suitable for the fabrication of micro/nanoscale devices. The low voltage WDW technique is anticipated to be useful for a broad range of applications including flexible/stretchable electronics, micro optoelectronics, nano-antennas, microelectromechanical systems (MEMS), and biomedical engineering.

  19. Multifunctional sensor network for structural state sensing and structural health monitoring

    NASA Astrophysics Data System (ADS)

    Qing, Xinlin P.; Ikegami, Roy; Beard, Shawn J.; Zhang, David; Das, Samik; Banerjee, Sourav; Chang, Fu-Kuo

    2010-04-01

    In order to take full advantages of composites and enable future composite structures to operate at their physical limits rather than limits predetermined from computational design assumptions and safety factors, there is a need to develop an embeddable sensing system to allow a structure to "feel" and "think" its structural state. In this paper, the concept of multi-modal sensing capabilities using a network of multifunctional sensors integrated with a structure has been developed. Utilizing this revolutionary concept, future structures can be designed and manufactured to provide multiple modes of information that when synthesized together can provide capabilities for intelligent sensing, environmental adaptation and multi-functionality. To demonstrate the feasibility of multi-modal sensing capabilities with built-in sensor network, one single type of piezoelectric sensor was selected to perform the measurements of dynamic strain, temperature, damage detection and impact monitoring. The uniqueness of the sensing system includes (1) Flexible, multifunctional sensor networks for integration with any type of composite structural component, (2) Scalable sensor network for monitoring of a large composite structure, (3) Reduced number of connecting wires for sensors, (4) Hybrid diagnostics with multiple sensing capabilities, (5) Sensor network self-diagnostics and self-repair for damaged sensor system.

  20. Investigation on spectral response of micro-cavity structure by symmetrical tapered fiber tips

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Li, Yang; Yan, Xiaojun; Li, Weidong

    2016-06-01

    We proposed and experimentally demonstrated a micro-cavity structure made of symmetrical tapered fiber tips. The waist of a conventional fiber taper fabricated from heating and stretching technique is symmetrically cleaved, and the aligned fiber tips with air gap constitute a Fabry-Perot micro-cavity due to the reflection at the tip facet. The spectral responses of such micro-cavity structure have been investigated both in beam propagation models and experiments. The multibeam interference in the micro-cavity and the impact of the waist diameter and cavity length on the spectral response has been successfully demonstrated. And a micro-cavity structure with 45 μm waist diameter was experimentally achieved, the measured spectra agree well with the simulation ones, indicating that the spectral response of the micro-cavity structure is contributed by both the multibeam interference and the Fabry-Perot micro-cavity.

  1. Combined Micro-chemical and Micro-structural Analysis of New Minerals Representing Extreme Conditions

    NASA Astrophysics Data System (ADS)

    Ma, C.; Tschauner, O. D.

    2015-12-01

    Recent improvements in micro-chemical analysis in combination with novel tools for micrometer-scale structural analysis of minerals from synchrotron X-ray diffraction open a pathway towards studies of mineral paragenesis that were previously not or barely accessible. Often mineral assemblies that represent extreme conditions also pose extreme challenges to analysis: very small size scale, complex matrix, minor amounts of material. Examples of such extreme, but also quite relevant environments are: a) High pressure shock-metamorphic minerals in meteorites and terrestrial impact sites, b) inclusions in diamonds from the deep mantle, c) ultrarefractory phases in Ca-Al-inlcusions from the solar nebula, d) presolar condensates. We show how a combination of synchrotron-based structural and semi-quantitative chemical techniques, with electron-microscopy based high-resolution imaging and fully quantitative chemical analysis and qualitative structural identification establish a powerful tool for discovery and characterization of important and interesting new minerals on micron- to submicron size scale.

  2. Scheduling policies of intelligent sensors and sensor/actuators in flexible structures

    NASA Astrophysics Data System (ADS)

    Demetriou, Michael A.; Potami, Raffaele

    2006-03-01

    In this note, we revisit the problem of actuator/sensor placement in large civil infrastructures and flexible space structures within the context of spatial robustness. The positioning of these devices becomes more important in systems employing wireless sensor and actuator networks (WSAN) for improved control performance and for rapid failure detection. The ability of the sensing and actuating devices to possess the property of spatial robustness results in reduced control energy and therefore the spatial distribution of disturbances is integrated into the location optimization measures. In our studies, the structure under consideration is a flexible plate clamped at all sides. First, we consider the case of sensor placement and the optimization scheme attempts to produce those locations that minimize the effects of the spatial distribution of disturbances on the state estimation error; thus the sensor locations produce state estimators with minimized disturbance-to-error transfer function norms. A two-stage optimization procedure is employed whereby one first considers the open loop system and the spatial distribution of disturbances is found that produces the maximal effects on the entire open loop state. Once this "worst" spatial distribution of disturbances is found, the optimization scheme subsequently finds the locations that produce state estimators with minimum transfer function norms. In the second part, we consider the collocated actuator/sensor pairs and the optimization scheme produces those locations that result in compensators with the smallest norms of the disturbance-to-state transfer functions. Going a step further, an intelligent control scheme is presented which, at each time interval, activates a subset of the actuator/sensor pairs in order provide robustness against spatiotemporally moving disturbances and minimize power consumption by keeping some sensor/actuators in sleep mode.

  3. Micro-Machined Thin Film Sensor Arrays For The Detection Of H2, Containing Gases, And Method Of Making And Using The Same.

    DOEpatents

    DiMeo, Jr., Frank; Baum, Thomas H.

    2003-07-22

    The present invention provides a hydrogen sensor including a thin film sensor element formed by metal organic chemical vapor deposition (MOCVD) or physical vapor deposition (PVD), on a micro-hotplate structure. The thin film sensor element includes a film of a hydrogen-interactive metal film that reversibly interacts with hydrogen to provide a correspondingly altered response characteristic, such as optical transmissivity, electrical conductance, electrical resistance, electrical capacitance, magneto resistance, photoconductivity, etc., relative to the response characteristic of the film in the absence of hydrogen. The hydrogen-interactive metal film may be overcoated with a thin film hydrogen-permeable barrier layer to protect the hydrogen-interactive film from deleterious interaction with non-hydrogen species. The hydrogen permeable barrier may comprise species to scavenge oxygen and other like species. The hydrogen sensor of the invention may be usefully employed for the detection of hydrogen in an environment susceptible to the incursion or generation of hydrogen and may be conveniently configured as a hand-held apparatus.

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

    NASA Astrophysics Data System (ADS)

    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

  5. Enhancing the sensitivity of a micro-diaphragm resonating sensor by effectively positioning the mass on the membrane

    PubMed Central

    Kim, Jinsik; Kim, Hye Jin; Cho, EunAe; Shin, Hyun-Joon; Park, Jung Ho; Hwang, Kyo Seon

    2015-01-01

    The detection of biomarkers in the liquid phase using mechanical sensors is difficult because of noise caused by the liquid. To reduce and verify the side effects of liquid loading, we performed calculations and experiments to determine the shift in resonant frequency according to the loading conditions. A 2-μm-thick piezoelectric rectangular micro-diaphragm with a 500 × 500 μm membrane was used. These dimensions were determined such that there would be an analogous resonant frequency shift ratio in both (1, 1) and (2, 2) modes. By calculating and measuring the resonant frequency, we verified that the resonant frequency of the sensor would change only through contact with the liquid, even the resonant frequency change by only liquid much higher than the changes caused by the nanoparticles. The real signal constituted only 0.017% of the initial resonant frequency. To enhance the sensitivity by reducing the unexpected surface stress in the liquid, the liquid was dropped onto the surface of the micro-diaphragm. This resulted in an improvement of more than 10 times the sensitivity in both modes. In addition, by controlling the position in the micro-diaphragm resonating sensor, more sensitive positions with large displacements were determined according to each mode. PMID:26594022

  6. Measurement of Gas-Liquid Two-Phase Flow in Micro-Pipes by a Capacitance Sensor

    PubMed Central

    Ji, Haifeng; Li, Huajun; Huang, Zhiyao; Wang, Baoliang; Li, Haiqing

    2014-01-01

    A capacitance measurement system is developed for the measurement of gas-liquid two-phase flow in glass micro-pipes with inner diameters of 3.96, 2.65 and 1.56 mm, respectively. As a typical flow regime in a micro-pipe two-phase flow system, slug flow is chosen for this investigation. A capacitance sensor is designed and a high-resolution and high-speed capacitance measurement circuit is used to measure the small capacitance signals based on the differential sampling method. The performance and feasibility of the capacitance method are investigated and discussed. The capacitance signal is analyzed, which can reflect the voidage variation of two-phase flow. The gas slug velocity is determined through a cross-correlation technique using two identical capacitance sensors. The simulation and experimental results show that the presented capacitance measurement system is successful. Research work also verifies that the capacitance sensor is an effective method for the measurement of gas liquid two-phase flow parameters in micro-pipes. PMID:25587879

  7. Measurement of wall shear stress in a pulsatile pipe flow system using micro-pillar shear sensor (MPS3)

    NASA Astrophysics Data System (ADS)

    Raghav, Vrishank; Garcia, Christine; Gnanamanickam, Ebenezer; Yoganathan, Ajit; GT-Embry-Riddle Collaboration

    2014-11-01

    The measurement of unsteady wall shear stress (WSS) in a pulsatile flow system is quite a challenge in experimental fluid mechanics. Recent developments in micro fabrication techniques have resulted in a novel measurement technique called the micro-pillar shear stress sensor (MPS3). It is a micro-pillar mounted on the surface of interest, which deflects an amount proportional to the shear stress it experiences. This technique has been widely used, validated and applied to measure turbulent WSS in several flow configurations. In this work, the MPS3 technique is used to measure WSS for a pulsatile fully developed pipe flow. The main objective here is to validate this technique for pulsatile pipe flow applications. For this purpose the WSS measurements obtained are compared with those obtained from analytical womersley solutions of the pulsatile flow system in the laminar flow regime. Statistical metrics will be used to better understand the measured WSS through the time period of the pulsatile flow.

  8. Virtual sensors for active noise control in acoustic-structural coupled enclosures using structural sensing: part II--Optimization of structural sensor placement.

    PubMed

    Halim, Dunant; Cheng, Li; Su, Zhongqing

    2011-04-01

    The work proposed an optimization approach for structural sensor placement to improve the performance of vibro-acoustic virtual sensor for active noise control applications. The vibro-acoustic virtual sensor was designed to estimate the interior sound pressure of an acoustic-structural coupled enclosure using structural sensors. A spectral-spatial performance metric was proposed, which was used to quantify the averaged structural sensor output energy of a vibro-acoustic system excited by a spatially varying point source. It was shown that (i) the overall virtual sensing error energy was contributed additively by the modal virtual sensing error and the measurement noise energy; (ii) each of the modal virtual sensing error system was contributed by both the modal observability levels for the structural sensing and the target acoustic virtual sensing; and further (iii) the strength of each modal observability level was influenced by the modal coupling and resonance frequencies of the associated uncoupled structural/cavity modes. An optimal design of structural sensor placement was proposed to achieve sufficiently high modal observability levels for certain important panel- and cavity-controlled modes. Numerical analysis on a panel-cavity system demonstrated the importance of structural sensor placement on virtual sensing and active noise control performance, particularly for cavity-controlled modes.

  9. Optimal sensor placement in structural health monitoring using discrete optimization

    NASA Astrophysics Data System (ADS)

    Sun, Hao; Büyüköztürk, Oral

    2015-12-01

    The objective of optimal sensor placement (OSP) is to obtain a sensor layout that gives as much information of the dynamic system as possible in structural health monitoring (SHM). The process of OSP can be formulated as a discrete minimization (or maximization) problem with the sensor locations as the design variables, conditional on the constraint of a given sensor number. In this paper, we propose a discrete optimization scheme based on the artificial bee colony algorithm to solve the OSP problem after first transforming it into an integer optimization problem. A modal assurance criterion-oriented objective function is investigated to measure the utility of a sensor configuration in the optimization process based on the modal characteristics of a reduced order model. The reduced order model is obtained using an iterated improved reduced system technique. The constraint is handled by a penalty term added to the objective function. Three examples, including a 27 bar truss bridge, a 21-storey building at the MIT campus and the 610 m high Canton Tower, are investigated to test the applicability of the proposed algorithm to OSP. In addition, the proposed OSP algorithm is experimentally validated on a physical laboratory structure which is a three-story two-bay steel frame instrumented with triaxial accelerometers. Results indicate that the proposed method is efficient and can be potentially used in OSP in practical SHM.

  10. Lessons learned in embedding fiber sensors into large civil structures

    NASA Astrophysics Data System (ADS)

    Ambrose, Timothy P.; Huston, Dryver R.; Fuhr, Peter L.

    1993-03-01

    Fiber optic cables have long since held the promise of providing low cost, widespread sensing capabilities. The use of fiber optic sensors within a large civil structure could allow for multiple sensing capabilities providing information as to the health of a structure. The Stafford Emerging Technologies Research Complex is a five-story, 65,000 square foot building currently under the final phases of construction on the campus of the University of Vermont. Over the course of the eight months approximately seventy fiber optic sensors have been installed within the concrete frame work of the building. The intrinsic and extrinsic fiber sensors are comprised of various types of singlemode and multimode cables. Since this project is the first major installation of it's kind, very little was known as to what techniques should be implemented to maximize fiber survivability. While installing the sensor network at the Stafford building site many lessons have been learned that would aid in future fiber installations. The techniques developed while installing fiber optic sensors are presented.

  11. Effects of structural parameters and rigidity of driving diaphragm on flow characteristics of micro valveless pump.

    PubMed

    Xie, Hai-bo; Fu, Xin; Yang, Hua-yong

    2003-01-01

    The structure and operating principle of micro valveless pump were investigated theoretically and experimentally. The mathematical model of pressure and flow rate within the micro nozzle/diffuser was established to analyze the effects of nozzle/diffuser parameters on the output flow rate of the micro valveless pump. The experiments were carried out with different structural parameters, driving frequencies, vibration amplitudes and stiffness of the driving diaphragms. Effects of the structural parameters and driving conditions on the operation performance of the pump are discussed in detail. The work provides useful reference for structure optimization selection of the driving diaphragm of micro valveless pump.

  12. Research and Development on In-Situ Measurement Sensors for Micro-Meteoroid and Small Space Debris at JAXA

    NASA Astrophysics Data System (ADS)

    Kitazawa, Yukihito; Matsumoto, Haruhisa; Okudaira, Osamu; Kimoto, Yugo; Hanada, Toshiya; Akahoshi, Yasuhiro; Pauline, Faure; Sakurai, Akira; Funakoshi, Kunihiro; Yasaka, Testuo

    2015-04-01

    The history of Japanese R&D into in-situ sensors for micro-meteoroid and orbital debris (MMOD) measurements is neither particularly long nor short. Research into active sensors started for the meteoroid observation experiment on the HITEN (MUSES-A) satellite of ISAS/JAXA launched in 1990, which had MDC (Munich Dust Counter) on-board sensors for micro meteoroid measurement. This was a collaboration between Technische Universität München and ISAS/JAXA. The main purpose behind the start of passive sensor research was SOCCOR, a late 80's Japan-US mission that planned to capture cometary dust and return to the Earth. Although this mission was canceled, the research outcomes were employed in a JAXA micro debris sample return mission using calibrated aerogel involving the Space Shuttle and the International Space Station. There have been many other important activities apart from the above, and the knowledge generated from them has contributed to JAXA's development of a new type of active dust sensor. JAXA and its partners have been developing a simple in-situ active dust sensor of a new type to detect dust particles ranging from a hundred micrometers to several millimeters. The distribution and flux of the debris in the size range are not well understood and is difficult to measure using ground observations. However, it is important that the risk caused by such debris is assessed. In-situ measurement of debris in this size range is useful for 1) verifying meteoroid and debris environment models, 2) verifying meteoroid and debris environment evolution models, and 3) the real time detection of explosions, collisions and other unexpected orbital events. Multitudes of thin, conductive copper strips are formed at a fine pitch of 100 um on a film 12.5 um thick of nonconductive polyimide. An MMOD particle impact is detected when one or more strips are severed by being perforated by such an impact. This sensor is simple to produce and use and requires almost no calibration as

  13. High speed fiber grating sensors for structural monitoring

    NASA Astrophysics Data System (ADS)

    Udd, Eric

    2014-06-01

    This paper provides an overview of selected applications of high speed structural monitoring using fiber grating sensors. Rapid and effective diagnostic capabilities are necessary to respond to changes in structural integrity that may affect safety. In the case of aerospace structures operating at high velocity rapid response has the potential to mitigate catastrophic failure. Similar safety issues apply to civil structures where timely decisions are critical to operations of bridges, dams and buildings. Rapid responses for oil and gas, medical and environmental monitoring applications are also highly important. A great deal of progress has been made in improving the quality and capabilities of high speed fiber grating sensor systems. Some of these systems will be discussed.

  14. Using a plenoptic sensor to reconstruct vortex phase structures.

    PubMed

    Wu, Chensheng; Ko, Jonathan; Davis, Christopher C

    2016-07-15

    A branch point problem and its solution commonly involve recognizing and reconstructing a vortex phase structure around a singular point. In laser beam propagation through random media, the destructive phase contributions from various parts of a vortex phase structure will cause a dark area in the center of the beam's intensity profile. This null of intensity can, in turn, prevent the vortex phase structure from being recognized. In this Letter, we show how to use a plenoptic sensor to transform the light field of a vortex beam so that a simple and direct reconstruction algorithm can be applied to reveal the vortex phase structure. As a result, we show that the plenoptic sensor is effective in detecting branch points and can be used to reconstruct phase distortion in a beam in a wide sense. PMID:27420487

  15. AOI [3] High-Temperature Nano-Derived Micro-H2 and - H2S Sensors

    SciTech Connect

    Sabolsky, Edward M.

    2014-08-01

    The emissions from coal-fired power plants remain a significant concern for air quality. This environmental challenge must be overcome by controlling the emission of sulfur dioxide (SO2) and hydrogen sulfide (H2S) throughout the entire coal combustion process. One of the processes which could specifically benefit from robust, low cost, and high temperature compatible gas sensors is the coal gasification process which converts coal and/or biomass into syngas. Hydrogen (H2), carbon monoxide (CO) and sulfur compounds make up 33%, 43% and 2% of syngas, respectively. Therefore, development of a high temperature (>500°C) chemical sensor for in-situ monitoring of H2, H2S and SO22 levels during coal gasification is strongly desired. The selective detection of SO2/H2S in the presence of H2, is a formidable task for a sensor designer. In order to ensure effective operation of these chemical sensors, the sensor system must inexpensively function within harsh temperature and chemical environment. Currently available sensing approaches, which are based on gas chromatography, electrochemistry, and IR-spectroscopy, do not satisfy the required cost and performance targets. This work focused on the development microsensors that can be applied to this application. In order to develop the high- temperature compatible microsensor, this work addressed various issues related to sensor stability, selectivity, and miniaturization. In the research project entitled “High-Temperature Nano-Derived Micro-H2 and -H2S Sensors”, the team worked to develop micro-scale, chemical sensors and sensor arrays composed of nano-derived, metal-oxide composite materials to detect gases like H2, SO2, and H2S within high-temperature environments (>500°C). The research was completed in collaboration with NexTech Materials, Ltd. (Lewis Center, Ohio). Nex

  16. Design and Characterization of a Sensorized Microfluidic Cell-Culture System with Electro-Thermal Micro-Pumps and Sensors for Cell Adhesion, Oxygen, and pH on a Glass Chip

    PubMed Central

    Bonk, Sebastian M.; Stubbe, Marco; Buehler, Sebastian M.; Tautorat, Carsten; Baumann, Werner; Klinkenberg, Ernst-Dieter; Gimsa, Jan

    2015-01-01

    We combined a multi-sensor glass-chip with a microfluidic channel grid for the characterization of cellular behavior. The grid was imprinted in poly-dimethyl-siloxane. Mouse-embryonal/fetal calvaria fibroblasts (MC3T3-E1) were used as a model system. Thin-film platinum (Pt) sensors for respiration (amperometric oxygen electrode), acidification (potentiometric pH electrodes) and cell adhesion (interdigitated-electrodes structures, IDES) allowed us to monitor cell-physiological parameters as well as the cell-spreading behavior. Two on-chip electro-thermal micro-pumps (ETμPs) permitted the induction of medium flow in the system, e.g., for medium mixing and drug delivery. The glass-wafer technology ensured the microscopic observability of the on-chip cell culture. Connecting Pt structures were passivated by a 1.2 μm layer of silicon nitride (Si3N4). Thin Si3N4 layers (20 nm or 60 nm) were used as the sensitive material of the pH electrodes. These electrodes showed a linear behavior in the pH range from 4 to 9, with a sensitivity of up to 39 mV per pH step. The oxygen sensors were circular Pt electrodes with a sensor area of 78.5 μm2. Their sensitivity was 100 pA per 1% oxygen increase in the range from 0% to 21% oxygen (air saturated). Two different IDES geometries with 30- and 50-μm finger spacings showed comparable sensitivities in detecting the proliferation rate of MC3T3 cells. These cells were cultured for 11 days in vitro to test the biocompatibility, microfluidics and electric sensors of our system under standard laboratory conditions. PMID:26263849

  17. Design and Characterization of a Sensorized Microfluidic Cell-Culture System with Electro-Thermal Micro-Pumps and Sensors for Cell Adhesion, Oxygen, and pH on a Glass Chip.

    PubMed

    Bonk, Sebastian M; Stubbe, Marco; Buehler, Sebastian M; Tautorat, Carsten; Baumann, Werner; Klinkenberg, Ernst-Dieter; Gimsa, Jan

    2015-07-30

    We combined a multi-sensor glass-chip with a microfluidic channel grid for the characterization of cellular behavior. The grid was imprinted in poly-dimethyl-siloxane. Mouse-embryonal/fetal calvaria fibroblasts (MC3T3-E1) were used as a model system. Thin-film platinum (Pt) sensors for respiration (amperometric oxygen electrode), acidification (potentiometric pH electrodes) and cell adhesion (interdigitated-electrodes structures, IDES) allowed us to monitor cell-physiological parameters as well as the cell-spreading behavior. Two on-chip electro-thermal micro-pumps (ETμPs) permitted the induction of medium flow in the system, e.g., for medium mixing and drug delivery. The glass-wafer technology ensured the microscopic observability of the on-chip cell culture. Connecting Pt structures were passivated by a 1.2 μm layer of silicon nitride (Si3N4). Thin Si3N4 layers (20 nm or 60 nm) were used as the sensitive material of the pH electrodes. These electrodes showed a linear behavior in the pH range from 4 to 9, with a sensitivity of up to 39 mV per pH step. The oxygen sensors were circular Pt electrodes with a sensor area of 78.5 μm(2). Their sensitivity was 100 pA per 1% oxygen increase in the range from 0% to 21% oxygen (air saturated). Two different IDES geometries with 30- and 50-μm finger spacings showed comparable sensitivities in detecting the proliferation rate of MC3T3 cells. These cells were cultured for 11 days in vitro to test the biocompatibility, microfluidics and electric sensors of our system under standard laboratory conditions.

  18. Micro structuration of gaas surface by wet etching: towards a specific surface behavior.

    PubMed

    Bienaime, Alex; Elie-Caille, Celine; Leblois, Therese

    2012-08-01

    Resonant microelectromechanical systems are promising devices for real time and highly sensitive measurements. The sensitivity of such sensors to additional mass loadings which can be increased thanks to the miniaturisation of devices is of prime importance for biological applications. The miniaturisation of structures passes through a photolithographic process and wet chemical etching. So, this paper presents new results on the anisotropic chemical etching of the gallium arsenide (GaAs) crystal used for this application, in several solutions. This paper focuses on the micro/nanostructuration of the sensing surface to increase the sensor sensitivity. Indeed, this active surface will be biofunctionalized to operate in biological liquid media in view of biomolecules detection. Several experimental conditions of etching bath composition, concentration and temperature were examined to obtain a large variety of geometrical surfaces topographies and roughness. According to the orientation dependence of the chemical etching process, the experiments were also performed on various GaAs crystal plates. The bath 1 H3PO4:9 H2O2:1 H2O appeared to be particularly adapted to the fabrication of the GaAs microstructured membrane: indeed, the bath is highly stable, anisotropic, and, as a function of temperature, it allows the production of a large variety of GaAs surface topographies.

  19. A time-based front-end ASIC for the silicon micro strip sensors of the bar PANDA Micro Vertex Detector

    NASA Astrophysics Data System (ADS)

    Di Pietro, V.; Brinkmann, K.-Th.; Riccardi, A.; Ritman, J.; Rivetti, A.; Rolo, M. D.; Stockmanns, T.; Zambanini, A.

    2016-03-01

    The bar PANDA (Antiproton Annihilation at Darmstadt) experiment foresees many detectors for tracking, particle identification and calorimetry. Among them, the innermost is the MVD (Micro Vertex Detector) responsible for a precise tracking and the reconstruction of secondary vertices. This detector will be built from both hybrid pixel (two inner barrels and six forward disks) and double-sided micro strip (two outer barrels and outer rim of the last two disks) silicon sensors. A time-based approach has been chosen for the readout ASIC of the strip sensors. The PASTA (bar PANDA Strip ASIC) chip aims at high resolution time-stamping and charge information through the Time over Threshold (ToT) technique. It benefits from a Time to Digital Converter (TDC) allowing a time bin width down to 50 ps. The analog front-end was designed to serve both n-type and p-type strips and the performed simulations show remarkable performances in terms of linearity and electronic noise. The TDC consists of an analog interpolator, a digital local controller, and a digital global controller as the common back-end for all of the 64 channels.

  20. Ion Channel Voltage Sensors: Structure, Function, and Pathophysiology

    PubMed Central

    Catterall, William A.

    2010-01-01

    Voltage-gated ion channels generate electrical signals in species from bacteria to man. Their voltage-sensing modules are responsible for initiation of action potentials and graded membrane potential changes in response to synaptic input and other physiological stimuli. Extensive structure-function studies, structure determination, and molecular modeling are now converging on a sliding-helix mechanism for electromechanical coupling in which outward movement of gating charges in the S4 transmembrane segments catalyzed by sequential formation of ion pairs pulls the S4-S5 linker, bends the S6 segment, and opens the pore. Impairment of voltage-sensor function by mutations in Na+ channels contributes to several ion channelopathies, and gating pore current conducted by mutant voltage sensors in NaV1.4 channels is the primary pathophysiological mechanism in Hypokalemic Periodic Paralysis. The emerging structural model for voltage sensor function opens the way to development of a new generation of ionchannel drugs that act on voltage sensors rather than blocking the pore. PMID:20869590

  1. Sensor Placement Guide for Structural Joint Stiffness Model Improvement

    NASA Astrophysics Data System (ADS)

    Kim, H. B.; Park, Y. S.

    1997-09-01

    The first requirement for an effective structural dynamic modification and control is an accurate finite element (FE model) having dynamic properties (natural frequencies and mode shapes, etc.) close to the measured values from real structures. The differences between the two models are attributed mainly to the uncertainties on joint regions, so an intermediate process to improve the FE model by adjusting and identifying joint properties is needed. A robust identification method is necessary to get reliable joint characteristics, and the selection of sensor positions plays a key role. All present methods of sensor positioning are a compromise between reliability and efficiency. This paper suggests a faster, automatic and more reliable sensor placement method. Based on an iterative scheme, it is similar to the effective independent method. Also, to overcome the shortcomings of the previous methods, it proposes a maximum allowable number of degrees of freedom that can be deleted at each iteration. This increases the ability to select optimum sensor positions. The suggested method was tested and verified with a satellite solar array and a T-shaped beam structure.

  2. Bio-mimetic optical sensor for structural deflection measurement

    NASA Astrophysics Data System (ADS)

    Frost, Susan A.; Wright, Cameron H. G.; Streeter, Robert W.; Khan, Md. A.; Barrett, Steven F.

    2014-03-01

    Reducing the environmental impact of aviation is a primary goal of NASA aeronautics research. One approach to achieve this goal is to build lighter weight aircraft, which presents complex challenges due to a corresponding increase in structural flexibility. Wing flexibility can adversely affect aircraft performance from the perspective of aerodynamic efficiency and safety. Knowledge of the wing position during flight can aid active control methods designed to mitigate problems due to increased wing flexibility. Current approaches to measuring wing deflection, including strain measurement devices, accelerometers, or GPS solutions, and new technologies such as fiber optic strain sensors, have limitations for their practical application to flexible aircraft control. Hence, it was proposed to use a bio-mimetic optical sensor based on the fly-eye to track wing deflection in real-time. The fly-eye sensor has several advantages over conventional sensors used for this application, including light weight, low power requirements, fast computation, and a small form factor. This paper reports on the fly-eye sensor development and its application to real-time wing deflection measurement.

  3. Wireless sensor networks for active vibration control in automobile structures

    NASA Astrophysics Data System (ADS)

    Mieyeville, Fabien; Ichchou, Mohamed; Scorletti, Gérard; Navarro, David; Du, Wan

    2012-07-01

    Wireless sensor networks (WSNs) are nowadays widely used in monitoring and tracking applications. This paper presents the feasibility of using WSNs in active vibration control strategies. The method employed here involves active-structural acoustic control using piezoelectric sensors distributed on a car structure. This system aims at being merged with a WSN whose head node collects data and processes control laws so as to command piezoelectric actuators wisely placed on the structure. We will study the feasibility of implementing WSNs in active vibration control and introduce a complete design methodology to optimize hardware/software and control law synergy in mechatronic systems. A design space exploration will be conducted so as to identify the best WSN platform and the resulting impact on control.

  4. Optical micro resonance based sensor schemes for detection and identification of nano particles and biological agents in situ

    NASA Astrophysics Data System (ADS)

    Saetchnikov, Vladimir A.; Tcherniavskaia, Elina A.; Schweiger, Gustav; Ostendorf, Andreas

    2010-05-01

    A novel emerging technique for the label-free analysis of nano particles including biomolecules using optical micro cavity resonance is being developed. Various schemes based on a mechanically fixed microspheres as well as microspheres melted by laser on the tip of a standard single mode fiber have been investigated to make further development for microbial application. Water solutions of ethanol, HCl, glucose, vitamin C and biotin have been used to test refractive index changes by monitoring the magnitude of the whispering gallery modes spectral shift. Particular efforts were made for effective fixing of the micro spheres in the water flow, an optimal geometry for micro resonance observation and material of microsphere the most appropriate for microbial application. Optical resonance in free micro spheres from PMMA fixed in micro channels produced by photolithography has been observed under the laser power of less then 1 microwatt. Resonance shifts of C reactive protein water solutions as well as albumin solutions in pure water and with HCl modelling blood have been investigated. Introducing controlled amount of glass gel nano particles into sensor microsphere surrounding were accompanied by both correlative resonance shift (400 nm in diameter) and total reconstruct of resonance spectra (57 nm in diameter). Developed schemes have been demonstrated to be a promising technology platform for sensitive, lab-on-chip type sensor of diagnostic tools for different biological molecules, e.g. proteins, oligonucleotides, oligosaccharides, lipids, small molecules, viral particles, cells as well as in different experimental contexts e.g. proteomics, genomics, drug discovery, and membrane studies.

  5. Construction of micro-nano network structure on titanium surface for improving bioactivity

    NASA Astrophysics Data System (ADS)

    Jiang, Pinliang; Liang, Jianhe; Lin, Changjian

    2013-09-01

    A novel hierarchical micro-nano structured titania layer was constructed on Ti surface to mimic the multi-level bone structure. The Ti substrate was subjected to a suitable acid etching and subsequent anodization in NaOH electrolyte to form a micro-nano porous titania layer. It was indicated that this microporous/nano-network (micro/nano-network) structured surface presented the enhanced wettability and superhydrophilic property. The polarization curve measurements showed that the as-prepared micro/nano-network structured TiO2 surface was of better corrosion resistance compared to the blank Ti surface, according to its corrosion current decreased, corrosion potential shifted positively and polarization resistance increased in Hank's solution. Meanwhile, the Mott-Schottky plots revealed that less oxygen vacancies existed in the micro/nano-network structured TiO2 film in contrast to the natural oxide film on blank Ti surface. Moreover, it was observed that the micro/nano-network structured surface was completely covered by a homogeneous apatite layer when immersed in simulated body fluid (SBF) for 14 days, exhibiting an excellent ability of biomineration. Furthermore, the superior cell adhesion and viability were discerned on such hierarchically structured surface, through a comparison of MG63 cell behaviors on blank Ti surface, nano-network structured surface and micro/nano-network structured surface. All results suggest our construction of micro-nano porous TiO2 surface is a promising strategy for improving the bioactivity of titanium implants.

  6. Active sensors for health monitoring of aging aerospace structures

    SciTech Connect

    GIURGIUTIU,VICTOR; REDMOND,JAMES M.; ROACH,DENNIS P.; RACKOW,KIRK A.

    2000-03-08

    A project to develop non-intrusive active sensors that can be applied on existing aging aerospace structures for monitoring the onset and progress of structural damage (fatigue cracks and corrosion) is presented. The state of the art in active sensors structural health monitoring and damage detection is reviewed. Methods based on (a) elastic wave propagation and (b) electro-mechanical (NM) impedance technique are sighted and briefly discussed. The instrumentation of these specimens with piezoelectric active sensors is illustrated. The main detection strategies (E/M impedance for local area detection and wave propagation for wide area interrogation) are discussed. The signal processing and damage interpretation algorithms are tuned to the specific structural interrogation method used. In the high-frequency EIM impedance approach, pattern recognition methods are used to compare impedance signatures taken at various time intervals and to identify damage presence and progression from the change in these signatures. In the wave propagation approach, the acoustic-ultrasonic methods identifying additional reflection generated from the damage site and changes in transmission velocity and phase are used. Both approaches benefit from the use of artificial intelligence neural networks algorithms that can extract damage features based on a learning process. Design and fabrication of a set of structural specimens representative of aging aerospace structures is presented. Three built-up specimens, (pristine, with cracks, and with corrosion damage) are used. The specimen instrumentation with active sensors fabricated at the University of South Carolina is illustrated. Preliminary results obtained with the E/M impedance method on pristine and cracked specimens are presented.

  7. Active sensors for health monitoring of aging aerospace structures

    SciTech Connect

    GIURGIUTIU,VICTOR; REDMOND,JAMES M.; ROACH,DENNIS P.; RACKOW,KIRK A.

    2000-02-29

    A project to develop non-intrusive active sensors that can be applied on existing aging aerospace structures for monitoring the onset and progress of structural damage (fatigue cracks and corrosion) is presented. The state of the art in active sensors structural health monitoring and damage detection is reviewed. Methods based on (a) elastic wave propagation and (b) electro-mechanical (E/M) impedance technique are cited and briefly discussed. The instrumentation of these specimens with piezoelectric active sensors is illustrated. The main detection strategies (E/M impedance for local area detection and wave propagation for wide area interrogation) are discussed. The signal processing and damage interpretation algorithms are tuned to the specific structural interrogation method used. In the high-frequency E/M impedance approach, pattern recognition methods are used to compare impedance signatures taken at various time intervals and to identify damage presence and progression from the change in these signatures. In the wave propagation approach, the acousto-ultrasonic methods identifying additional reflection generated from the damage site and changes in transmission velocity and phase are used. Both approaches benefit from the use of artificial intelligence neural networks algorithms that can extract damage features based on a learning process. Design and fabrication of a set of structural specimens representative of aging aerospace structures is presented. Three built-up specimens (pristine, with cracks, and with corrosion damage) are used. The specimen instrumentation with active sensors fabricated at the University of South Carolina is illustrated. Preliminary results obtained with the E/M impedance method on pristine and cracked specimens are presented.

  8. New developments in the manufacture of large freeform surfaces with micro-structures

    NASA Astrophysics Data System (ADS)

    Roblee, Jeff; Walter, Mark; Jacobs, Ben

    2015-10-01

    A new capability for simultaneously generating micro-structures and large freeform surfaces has been developed. Multiple axes of CNC coordinated motion have been integrated into an ultra precision machine platform, enabling a wide variety of optical mold masters to be created. Facilitated by a specially developed control system, freeform optical surfaces as large as 600 x 600 x 100 mm are possible. Some machine alignments are critical to the production of accurate parts and these will be discussed. A bridge construction reduces Abbe offsets, and oil hydrostatic linear slide ways provide sub-micron straightness. The linear axes are capable of accurate positioning by means of linear motors in combination with the non contact oil hydrostatic slide ways. Optical surface finishes are achieved with the stability of a large granite base supported by a high performance vibration isolation system. The machine includes a unique, self-compensating, patented oil bearing rotary axis. Critical machine errors are measured and corrected with integrated CNC machine compensation. The machine has accuracy and repeatability for the creation of precise, intersecting groove structures with multiple angles over large areas. Optical surfaces can be generated either by a ruling/shaping operation with a non-rotating tool, or by a flycutting tool rotating on a high speed air bearing spindle. The spindle can double as a positioning axis to generate variable angle grooves in ruling mode. A Fast Tool Servo can be utilized to create fine micro-structures. Work piece quality can be evaluated in-situ with metrology sensors.

  9. Three-dimensional micro-printing of temperature sensors based on up-conversion luminescence

    SciTech Connect

    Wickberg, Andreas; Mueller, Jonathan B.; Mange, Yatin J.; Nann, Thomas; Fischer, Joachim; Wegener, Martin

    2015-03-30

    The pronounced temperature dependence of up-conversion luminescence from nanoparticles doped with rare-earth elements enables local temperature measurements. By mixing these nanoparticles into a commercially available photoresist containing the low-fluorescence photo-initiator Irgacure 369, and by using three-dimensional direct laser writing, we show that micrometer sized local temperature sensors can be positioned lithographically as desired. Positioning is possible in pre-structured environments, e.g., within buried microfluidic channels or on optical or electronic chips. We use the latter as an example and demonstrate the measurement for both free space and waveguide-coupled excitation and detection. For the free space setting, we achieve a temperature standard deviation of 0.5 K at a time resolution of 1 s.

  10. A MEMS thermal shear stress sensor produced by a combination of substrate-free structures with anodic bonding technology

    NASA Astrophysics Data System (ADS)

    Ou, Yi; Qu, Furong; Wang, Guanya; Nie, Mengyan; Li, Zhigang; Ou, Wen; Xie, Changqing

    2016-07-01

    By combining substrate-free structures with anodic bonding technology, we present a simple and efficient micro-electro-mechanical system (MEMS) thermal shear stress sensor. Significantly, the resulting depth of the vacuum cavity of the sensor is determined by the thickness of the silicon substrate at which Si is removed by the anisotropic wet etching process. Compared with the sensor based on a sacrificial layer technique, the proposed MEMS thermal shear-stress sensor exhibits dramatically improved sensitivity due to the much larger vacuum cavity depth. The fabricated MEMS thermal shear-stress sensor with a vacuum cavity depth as large as 525 μm and a vacuum of 5 × 10-2 Pa exhibits a sensitivity of 184.5 mV/Pa and a response time of 180 μs. We also experimentally demonstrate that the sensor power is indeed proportional to the 1/3-power of the applied shear stress. The substrate-free structures offer the ability to precisely measure the shear stress fluctuations in low speed turbulent boundary layer wind tunnels.

  11. Analysis of Piezoelectric Structural Sensors with Emergent Computing Techniques

    NASA Technical Reports Server (NTRS)

    Ramers, Douglas L.

    2005-01-01

    The purpose of this project was to try to interpret the results of some tests that were performed earlier this year and to demonstrate a possible use of emergence in computing to solve IVHM problems. The test data used was collected with piezoelectric sensors to detect mechanical changes in structures. This project team was included of Dr. Doug Ramers and Dr. Abdul Jallob of the Summer Faculty Fellowship Program, Arnaldo Colon-Lopez - a student intern from the University of Puerto Rico of Turabo, and John Lassister and Bob Engberg of the Structural and Dynamics Test Group. The tests were performed by Bob Engberg to compare the performance two types of piezoelectric (piezo) sensors, Pb(Zr(sub 1-1)Ti(sub x))O3, which we will label PZT, and Pb(Zn(sub 1/3)Nb(sub 2/3))O3-PbTiO, which we will label SCP. The tests were conducted under varying temperature and pressure conditions. One set of tests was done by varying water pressure inside an aluminum liner covered with carbon-fiber composite layers (a cylindrical "bottle" with domed ends) and the other by varying temperatures down to cryogenic levels on some specially prepared composite panels. This report discusses the data from the pressure study. The study of the temperature results was not completed in time for this report. The particular sensing done with these piezo sensors is accomplished by the sensor generating an controlled vibration that is transmitted into the structure to which the sensor is attached, and the same sensor then responding to the induced vibration of the structure. There is a relationship between the mechanical impedance of the structure and the resulting electrical impedance produced in the in the piezo sensor. The impedance is also a function of the excitation frequency. Changes in the real part of impendance signature relative to an original reference signature indicate a change in the coupled structure that could be the results of damage or strain. The water pressure tests were conducted by

  12. A wireless MEMS-based inclinometer sensor node for structural health monitoring.

    PubMed

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

    2013-11-26

    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.

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

    PubMed Central

    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

  14. Micro-structured PDMS piezoelectric enhancement through charging conditions

    NASA Astrophysics Data System (ADS)

    Kachroudi, Achraf; Basrour, Skandar; Rufer, Libor; Sylvestre, Alain; Jomni, Fathi

    2016-10-01

    Micro-structured cellular polydimethylsiloxane (PDMS) materials were prepared by a low-cost molding process allowing us to control geometry and sample size. Cellular structures are charged with a triangular quasi-static voltage with amplitudes between 1 kV and 4 kV and a frequency of 0.5 Hz fixed after having evaluated the conditions enhancing the piezoelectric response of the cellular PDMS. The piezo-electret PDMS material charged at room temperature has a piezoelectric coefficient d 33 of 350 pC/N, which is ten times larger than that of polyvinylidene fluoride. The high piezoelectric coefficient with a very low elastic modulus of 300 kPa makes these materials very useful for wearable device applications. The piezoelectric coefficient d 33 of the samples poled at high temperatures improves thermal stability but reduces PDMS piezo-electret piezoelectricity, which is explained by the structure’s stiffness. These results are useful and allow us to set the conditions for the preparation of the piezo-electret materials according to desired applications.

  15. Adaptive sensor array algorithm for structural health monitoring of helmet

    NASA Astrophysics Data System (ADS)

    Zou, Xiaotian; Tian, Ye; Wu, Nan; Sun, Kai; Wang, Xingwei

    2011-04-01

    The adaptive neural network is a standard technique used in nonlinear system estimation and learning applications for dynamic models. In this paper, we introduced an adaptive sensor fusion algorithm for a helmet structure health monitoring system. The helmet structure health monitoring system is used to study the effects of ballistic/blast events on the helmet and human skull. Installed inside the helmet system, there is an optical fiber pressure sensors array. After implementing the adaptive estimation algorithm into helmet system, a dynamic model for the sensor array has been developed. The dynamic response characteristics of the sensor network are estimated from the pressure data by applying an adaptive control algorithm using artificial neural network. With the estimated parameters and position data from the dynamic model, the pressure distribution of the whole helmet can be calculated following the Bazier Surface interpolation method. The distribution pattern inside the helmet will be very helpful for improving helmet design to provide better protection to soldiers from head injuries.

  16. High temperature strain sensor based on a fiber Bragg grating and rhombus metal structure.

    PubMed

    Zhang, Liang; Liu, Yueming; Gao, Xiaoliang; Xia, Zhongcheng

    2015-10-01

    In this paper, a novel high temperature strain sensor based on a polyimide-coated fiber Bragg grating (FBG) and a rhombus metal structure is presented and experimentally demonstrated. By heating low softening point glass via a micro torch, the polyimide-coated FBG could be fixed into the rhombus metal structure. Consequently, when the rhombus structure is stretched and compressed, respectively, then the FBG will be subjected to a reverse state. Moreover, the strain sensitivity is controllable and enhanced by adjusting the dimension of the rhombus metal structure appropriately. The experiment was then carried out by using an equi-intensity cantilever beam and high temperature chamber, and the result showed that the proposed high temperature strain sensor could be used at the high temperature of 300°C. A resolution of ∼10  με has been experimentally achieved. The average wavelength strain sensitivity at 300°C is 1.821 and 1.814 pm/με, for the compressed and stretched states, respectively. PMID:26479639

  17. Impact load-induced micro-structural damage and micro-structure associated mechanical response of concrete made with different surface roughness and porosity aggregates

    SciTech Connect

    Erdem, Savas Dawson, Andrew Robert; Thom, Nicholas Howard

    2012-02-15

    The relationship between the nature of micro damage under impact loading and changes in mechanical behavior associated with different microstructures is studied for concretes made with two different coarse aggregates having significant differences mainly in roughness and porosity - sintered fly ash and uncrushed gravel. A range of techniques including X-ray diffraction, digital image analysis, mercury porosimetry, X-ray computed tomography, laser surface profilometry and scanning electron microscopy were used to characterize the aggregates and micro-structures. The concrete prepared with lightweight aggregates was stronger in compression than the gravel aggregate concrete due to enhanced hydration as a result of internal curing. In the lightweight concrete, it was deduced that an inhomogeneous micro-structure led to strain incompatibilities and consequent localized stress concentrations in the mix, leading to accelerated failure. The pore structure, compressibility, and surface texture of the aggregates are of paramount importance for the micro-cracking growth.

  18. Micro Sensor Node for Air Pollutant Monitoring: Hardware and Software Issues

    PubMed Central

    Choi, Sukwon; Kim, Nakyoung; Cha, Hojung; Ha, Rhan

    2009-01-01

    Wireless sensor networks equipped with various gas sensors have been actively used for air quality monitoring. Previous studies have typically explored system issues that include middleware or networking performance, but most research has barely considered the details of the hardware and software of the sensor node itself. In this paper, we focus on the design and implementation of a sensor board for air pollutant monitoring applications. Several hardware and software issues are discussed to explore the possibilities of a practical WSN-based air pollution monitoring system. Through extensive experiments and evaluation, we have determined the various characteristics of the gas sensors and their practical implications for air pollutant monitoring systems. PMID:22408489

  19. Structural integrity inspection and monitoring by magneto-optic sensors

    NASA Astrophysics Data System (ADS)

    Dudziak, Martin J.

    1999-01-01

    Non-destructive testing for cracks, fissures, fatigue stress, and corrosion has been demonstrated using eddy- current induced magnetic fields measurable by sensors with Faraday magneto-optic properties. A novel class of such sensors has been developed, the MODE sensor, using Fe-Ga thin-films of the general form (R, Bi)3 (M, Fe)5-12 with R equals (Y, Lu, Tm, or other rare earth ions) and M equals Ga or Al. These films are characterized by very high uniaxial anisotropic field, Faraday rotation, absorption coefficient, and MO figure of merit, significantly improving sensitivity over previous thin film compositions. These properties enable their use in highly compact portable or remotely operated devices and requiring either no eddy current or else brief microbursts of electric current rather than lengthy application of steady current in order to induce magnetic fields within observed structures. A portable system for the testing of bridge structural components, fuel tanks, gas cylinders, and other metallic structures has been designed. This apparatus makes use of a compact portable computer into which video output from the MODE sensor unit received. Using a conventional software interface the operator is able to view the same structure in real time and to apply an array of image processing refinement techniques for improving the resolution of the image. Images may be stored as a constant video stream or as a set of individual snapshots. Additional features that enhance the utility of the system for mobile inspection tasks are discussed. These include the incorporation of a pattern recognition training algorithm and library for operator-enhanced identification of structural defects and condition assessments, as well as the broadcast of image and location data via wireless link to a central server for distribution to consulting engineers and for access of Microstation-type CAD files via a web browser interface.

  20. Smart aircraft composite structures with embedded small-diameter optical fiber sensors

    NASA Astrophysics Data System (ADS)

    Takeda, Nobuo; Minakuchi, Shu

    2012-02-01

    This talk describes the embedded optical fiber sensor systems for smart aircraft composite structures. First, a summary of the current Japanese national project on structural integrity diagnosis of aircraft composite structures is described with special emphasis on the use of embedded small-diameter optical fiber sensors including FBG sensors. Then, some examples of life-cycle monitoring of aircraft composite structures are presented using embedded small-diameter optical fiber sensors for low-cost and reliable manufacturing merits.

  1. A piezo-driven micro-inclination stage for calibration of a micro-acceleration transducer: structure and control strategy

    NASA Astrophysics Data System (ADS)

    Shao, Shubao; Song, Siyang; Xu, Minglong; Xie, Shilin; Li, Liang

    2016-02-01

    In some space applications, such as space navigation and vibration control of the large space structures, micro-acceleration transducers are required and have to be calibrated accurately. Unfortunately, providing extremely small static and quasi-static stimuli (accelerations) for the calibration of the micro-acceleration transducer has been a challenging task. This paper proposes a novel piezo-driven micro-inclination stage (PMIS) that can produce both discrete and continuous tumbles in a gravity field so that extremely small static and quasi-static stimuli (accelerations) can be obtained from a tiny component of the gravity constant. The proposed PMIS, which is driven by the lead zirconate titanate (PZT) stack, employs a rhombic mechanism to provide the PZT stack with a proper preload for the purpose of outputting a bidirectional force. To produce accurate static and quasi-static stimuli, the hysteresis non-linearity inherent in PZT stack is compensated by employing the strain feedback based adaptive control where the hysteresis property is identified online using the controlled auto-regressive moving average model. Furthermore, to improve the resolution of strain feedback, the strain sensitivity is maximized through structure optimization of the rhombic mechanism. The experimental results demonstrated that the proposed PMIS can produce minimal micro-inclination of {{0.1}\\prime \\prime} (corresponding to the induced micro-acceleration of 0.5μ g ) with the frequency ranging from 0 (DC) to 2 Hz.

  2. Hemocompatibility research on the micro-structure surface of a bionic heart valve.

    PubMed

    Ye, Xia; Wang, Ze; Zhang, Xianghua; Zhou, Ming; Cai, Lan

    2014-01-01

    In order to study how the geometric parameters and shape of the micro-structure surface of a bionic heart valve affects hemocompatibility, mastoid micro-structures with different periodic space were fabricated using a femtosecond laser on a polyurethane (PU) surface. The apparent contact angles of droplets on the micro-structure surfaces were measured to characterize their wettability. Then a series of blood compatibility experiments, including platelet adhesion, dynamic coagulation and hemolysis were completed. The experimental results showed that the micro-structure on the biomaterial surface helped improve its hydrophobicity and hemocompatibility. Also, the periodic space affected not only the hydrophobicity but also the hemocompatibility of the biomaterial. With the increasing of the periodic space, the apparent contact angle increased, the number of platelet adhesion decreased, the dynamic clotting time became longer and the hemolysis ratio reduced. In addition, the shape of the micro-structure also affected the hemocompatibility of the biomaterial.

  3. Investigating the performance of catalyst layer micro-structures with different platinum loadings

    SciTech Connect

    Khakaz-Baboli, Moben; Harvey, David; Pharoah, Jon

    2012-07-01

    In this study a four-phase micro-structure of a PEFC catalyst layer was reconstructed by randomly placing overlapping spheres for each solid catalyst phase. The micro-structure was mirrored to make a micro-structure. A body-fit computational mesh was produced for the reconstructed micro-structure in OpenFOAM. Associated conservation equations were solved within all the phases with electrochemical reaction as the boundary condition at the interface between ionomer and platinum phases. The study is focused on the platinum loading of CL. The polarization curves of the micro-structure performance have been compared for different platinum loadings. This paper gives increased insight into the relatively greater losses at decreased platinum loadings.

  4. Hybrid optical-fibre/geopolymer sensors for structural health monitoring of concrete structures

    NASA Astrophysics Data System (ADS)

    Perry, M.; Saafi, M.; Fusiek, G.; Niewczas, P.

    2015-04-01

    In this work, we demonstrate hybrid optical-fibre/geopolymer sensors for monitoring temperature, uniaxial strain and biaxial strain in concrete structures. The hybrid sensors detect these measurands via changes in geopolymer electrical impedance, and via optical wavelength measurements of embedded fibre Bragg gratings. Electrical and optical measurements were both facilitated by metal-coated optical fibres, which provided the hybrid sensors with a single, shared physical path for both voltage and wavelength signals. The embedded fibre sensors revealed that geopolymer specimens undergo 2.7 mɛ of shrinkage after one week of curing at 42 °C. After curing, an axial 2 mɛ compression of the uniaxial hybrid sensor led to impedance and wavelength shifts of 7 × 10-2 and -2 × 10-4 respectively. The typical strain resolution in the uniaxial sensor was 100 μ \\varepsilon . The biaxial sensor was applied to the side of a concrete cylinder, which was then placed under 0.6 mɛ of axial, compressive strain. Fractional shifts in impedance and wavelength, used to monitor axial and circumferential strain, were 3 × 10-2 and 4 × 10-5 respectively. The biaxial sensor’s strain resolution was approximately 10 μ \\varepsilon in both directions. Due to several design flaws, the uniaxial hybrid sensor was unable to accurately measure ambient temperature changes. The biaxial sensor, however, successfully monitored local temperature changes with 0.5 °C resolution.

  5. Pipelining in structural health monitoring wireless sensor network

    NASA Astrophysics Data System (ADS)

    Li, Xu; Dorvash, Siavash; Cheng, Liang; Pakzad, Shamim

    2010-04-01

    Application of wireless sensor network (WSN) for structural health monitoring (SHM), is becoming widespread due to its implementation ease and economic advantage over traditional sensor networks. Beside advantages that have made wireless network preferable, there are some concerns regarding their performance in some applications. In long-span Bridge monitoring the need to transfer data over long distance causes some challenges in design of WSN platforms. Due to the geometry of bridge structures, using multi-hop data transfer between remote nodes and base station is essential. This paper focuses on the performances of pipelining algorithms. We summarize several prevent pipelining approaches, discuss their performances, and propose a new pipelining algorithm, which gives consideration to both boosting of channel usage and the simplicity in deployment.

  6. Sensor failure detection using generalized parity relations for flexible structures

    NASA Technical Reports Server (NTRS)

    Mercadal, Mathieu

    1989-01-01

    Analytical redundancy may be preferable to hardware redundancy in failure detection/isolation tasks for such large-scale systems as space structures. Generalized single-sensor parity relations are presently applied to this problem; they are noted to yield a very simple isolation logic, and their generation is found to be extremely rapid, even in the case of extremely complex systems, provided only that the eigenstructure of the system be known. Their implementation is, however, extremely sensitive to modeling errors and noise.

  7. Developing a robust wireless sensor network structure for environmental sensing

    NASA Astrophysics Data System (ADS)

    Zhang, Z.; Oroza, C.; Glaser, S. D.; Bales, R. C.; Conklin, M. H.

    2013-12-01

    The American River Hydrologic Observatory is being strategically deployed as a real-time ground-based measurement network that delivers accurate and timely information on snow conditions and other hydrologic attributes with a previously unheard of granularity of time and space. The basin-scale network involves 18 sub-networks set out at physiographically representative locations spanning the seasonally snow-covered half of the 5000 km2 American river basin. Each sub-network, covering about a 1-km2 area, consists of 10 wirelessly networked sensing nodes that continuously measure and telemeter temperature, and snow depth; plus selected locations are equipped with sensors for relative humidity, solar radiation, and soil moisture at several depths. The sensor locations were chosen to maximize the variance sampled for snow depth within the basin. Network design and deployment involves an iterative but efficient process. After sensor-station locations are determined, a robust network of interlinking sensor stations and signal repeaters must be constructed to route sensor data to a central base station with a two-way communicable data uplink. Data can then be uploaded from site to remote servers in real time through satellite and cell modems. Signal repeaters are placed for robustness of a self-healing network with redundant signal paths to the base station. Manual, trial-and-error heuristic approaches for node placement are inefficient and labor intensive. In that approach field personnel must restructure the network in real time and wait for new network statistics to be calculated at the base station before finalizing a placement, acting without knowledge of the global topography or overall network structure. We show how digital elevation plus high-definition aerial photographs to give foliage coverage can optimize planning of signal repeater placements and guarantee a robust network structure prior to the physical deployment. We can also 'stress test' the final network

  8. Detection of single magnetic bead for biological applications using an InAs quantum-well micro-Hall sensor

    NASA Astrophysics Data System (ADS)

    Mihajlović, Goran; Xiong, Peng; von Molnár, Stephan; Ohtani, Keita; Ohno, Hideo; Field, Mark; Sullivan, Gerard J.

    2005-09-01

    Room-temperature detection of a single commercial superparamagnetic bead (1.2μm in diameter) suitable for biological applications has been realized using an InAs quantum-well micro-Hall sensor. The detection was demonstrated using phase-sensitive detection on a single Hall cross as well as in a Hall gradiometry setup. The high signal to noise ratio, obtained in both configurations, promises detection of single nanometer-size particles by further miniaturization of the device to submicron dimensions.

  9. Fabrication and characterization of 3C-silicon carbide micro sensor for wireless blood pressure measurements

    NASA Astrophysics Data System (ADS)

    Basak, Nupur

    A potentially implantable single crystal 3C-SiC pressure sensor for blood pressure measurement was designed, simulated, fabricated, characterized and optimized. This research uses a single crystal 3C-SiC, for the first time, to demonstrate its application as a blood pressure measurement sensor. The sensor, which uses the epitaxial grown 3C-SiC membrane to measure changes in pressure, is designed to be wireless, biocompatible and linear. The SiC material was chosen for its superior physical, chemical and mechanical properties; the capacitive sensor uses a 3C-SiC membrane as one of the electrodes; and, the sensor system is wireless for comfort and to allow for convenient reading of real-time pressure data (wireless communication is enabled by connecting the sensor parallel to a planar inductor). Together, the variable capacitive sensor and planar inductor create a pressure sensitive resonant circuit. The sensor system described above allows for implantation into a human patient's body, after which the planar inductor can be coupled with an external inductor to receive data for real-time blood pressure measurement. Electroplating, thick photo-resist characterization, RIE etching, oxidation, CVD, chemical mechanical polishing and wafer bonding were optimized during the process of fabricating the sensor system and, in addition to detailing the sensor system simulation and characterization; the optimized processes are detailed in the dissertation. This absolute pressure sensor is designed to function optimally within the human blood pressure range of 50-350mmHg. The layout and modeling of the sensor uses finite element analysis (FEA) software. The simulations for membrane deflection, stress analysis and electro-mechanical analysis are performed for 100 μm2 and 400μm2sensors. The membrane deflection-pressure, capacitance-pressure and resonant frequency-pressure graphs were obtained, and detailed in the dissertation, along with the planar inductor simulation for

  10. Research and Development on In-Situ Measurement Sensors for Micro-Meteoroid and Small Space Debris at JAXA

    NASA Astrophysics Data System (ADS)

    Kitazawa, Y.; Matsumoto, H.; Okudaira, O.; Kimoto, Y.; Hanada, T.; Faure, P.; Akahoshi, Y.; Hattori, M.; Karaki, A.; Sakurai, A.; Funakoshi, K.; Yasaka, T.

    2013-08-01

    The Japan Aerospace Exploration Agency (JAXA) has been conducting R&D into in-situ sensors for measuring micro-meteoroid and small-sized debris (MMSD) since the 1980s. Research into active sensors started with the meteoroid observation experiment conducted using the HITEN (MUSES-A) satellite that ISAS/JAXA launched in 1990. The main purpose behind the start of passive collector research was SOCCER, a late-80s Japan-US mission that was designed to capture cometary dust and then return to the Earth. Although this mission was cancelled, the research outcomes were employed in a JAXA mission for the return of MMSD samples using calibrated aerogel and involving the space shuttle and the International Space Station. Many other important activities have been undertaken as well, and the knowledge they have generated has contributed to JAXA's development of a new type of active dust sensor. This paper reports on the R&D conducted at JAXA into in-situ MMSD measurement sensors.

  11. A sensitive optical micro-machined ultrasound sensor (OMUS) based on a silicon photonic ring resonator on an acoustical membrane

    NASA Astrophysics Data System (ADS)

    Leinders, S. M.; Westerveld, W. J.; Pozo, J.; van Neer, P. L. M. J.; Snyder, B.; O'Brien, P.; Urbach, H. P.; de Jong, N.; Verweij, M. D.

    2015-09-01

    With the increasing use of ultrasonography, especially in medical imaging, novel fabrication techniques together with novel sensor designs are needed to meet the requirements for future applications like three-dimensional intercardiac and intravascular imaging. These applications require arrays of many small elements to selectively record the sound waves coming from a certain direction. Here we present proof of concept of an optical micro-machined ultrasound sensor (OMUS) fabricated with a semi-industrial CMOS fabrication line. The sensor is based on integrated photonics, which allows for elements with small spatial footprint. We demonstrate that the first prototype is already capable of detecting pressures of 0.4 Pa, which matches the performance of the state of the art piezo-electric transducers while having a 65 times smaller spatial footprint. The sensor is compatible with MRI due to the lack of electronical wiring. Another important benefit of the use of integrated photonics is the easy interrogation of an array of elements. Hence, in future designs only two optical fibers are needed to interrogate an entire array, which minimizes the amount of connections of smart catheters. The demonstrated OMUS has potential applications in medical ultrasound imaging, non destructive testing as well as in flow sensing.

  12. A sensitive optical micro-machined ultrasound sensor (OMUS) based on a silicon photonic ring resonator on an acoustical membrane

    PubMed Central

    Leinders, S.M.; Westerveld, W.J.; Pozo, J.; van Neer, P.L.M.J.; Snyder, B.; O’Brien, P.; Urbach, H.P.; de Jong, N.; Verweij, M.D.

    2015-01-01

    With the increasing use of ultrasonography, especially in medical imaging, novel fabrication techniques together with novel sensor designs are needed to meet the requirements for future applications like three-dimensional intercardiac and intravascular imaging. These applications require arrays of many small elements to selectively record the sound waves coming from a certain direction. Here we present proof of concept of an optical micro-machined ultrasound sensor (OMUS) fabricated with a semi-industrial CMOS fabrication line. The sensor is based on integrated photonics, which allows for elements with small spatial footprint. We demonstrate that the first prototype is already capable of detecting pressures of 0.4 Pa, which matches the performance of the state of the art piezo-electric transducers while having a 65 times smaller spatial footprint. The sensor is compatible with MRI due to the lack of electronical wiring. Another important benefit of the use of integrated photonics is the easy interrogation of an array of elements. Hence, in future designs only two optical fibers are needed to interrogate an entire array, which minimizes the amount of connections of smart catheters. The demonstrated OMUS has potential applications in medical ultrasound imaging, non destructive testing as well as in flow sensing. PMID:26392386

  13. A sensitive optical micro-machined ultrasound sensor (OMUS) based on a silicon photonic ring resonator on an acoustical membrane.

    PubMed

    Leinders, S M; Westerveld, W J; Pozo, J; van Neer, P L M J; Snyder, B; O'Brien, P; Urbach, H P; de Jong, N; Verweij, M D

    2015-01-01

    With the increasing use of ultrasonography, especially in medical imaging, novel fabrication techniques together with novel sensor designs are needed to meet the requirements for future applications like three-dimensional intercardiac and intravascular imaging. These applications require arrays of many small elements to selectively record the sound waves coming from a certain direction. Here we present proof of concept of an optical micro-machined ultrasound sensor (OMUS) fabricated with a semi-industrial CMOS fabrication line. The sensor is based on integrated photonics, which allows for elements with small spatial footprint. We demonstrate that the first prototype is already capable of detecting pressures of 0.4 Pa, which matches the performance of the state of the art piezo-electric transducers while having a 65 times smaller spatial footprint. The sensor is compatible with MRI due to the lack of electronical wiring. Another important benefit of the use of integrated photonics is the easy interrogation of an array of elements. Hence, in future designs only two optical fibers are needed to interrogate an entire array, which minimizes the amount of connections of smart catheters. The demonstrated OMUS has potential applications in medical ultrasound imaging, non destructive testing as well as in flow sensing. PMID:26392386

  14. Midwave Infrared (2-6{micro}m) Emitter-Based Chemical Sensor Systems

    SciTech Connect

    Allerman, A.A.; Biefeld, R.M.; Kurtz, S.R.

    1999-02-01

    Long wavelength (2-6 {micro}m) diode emitters are desirable for many applications including monitoring of chemical species in the environment and manufacturing, long wavelength fiber-optic communications, lidar, and JR detector counter-measures. No practical diode lasers are available for any of these applications because the band structure of bulk III-V, II-VI, and IV-VI semiconductor alloys results in large Auger recombination rates at these wavelengths. Experimental and theoretical work at Sandia has resulted in new understanding of the electronic properties of narrow bandgap III-V heterostructures, and we have found methods of reducing the Auger rates in certain InAsSb superlattices and quantum wells. These devices enable us to begin chemical sensing demonstrations of important species such as CO-CO{sub 2} and numerous other compounds. This project will involve developing chemical sensing systems and determining the sensitivity and limitations of these systems. Concurrently, we will improve upon infrared emitters used in these systems.

  15. Rapid Characterization of Vegetation Structure with a Microsoft Kinect Sensor

    PubMed Central

    Azzari, George; Goulden, Michael L.; Rusu, Radu B.

    2013-01-01

    The importance of vegetation structure and biomass in controlling land-atmosphere exchange is widely recognized, but measurements of canopy structure are challenging, time consuming, and often rely on destructive methods. The Microsoft Kinect is an infrared sensor designed for video gaming that outputs synchronized color and depth images and that has the potential to allow rapid characterization of vegetation structure. We compared depth images from a Kinect sensor with manual measurements of plant structure and size for two species growing in a California grassland. The depth images agreed well with the horizontal and vertical measurements of plant size made manually. Similarly, the plant volumes calculated with a three-dimensional convex hulls approach was well related to plant biomass. The Kinect showed some limitations for ecological observation associated with a short measurement range and daytime light contamination. Nonetheless, the Kinect's light weight, fast acquisition time, low power requirement, and cost make it a promising tool for rapid field surveys of canopy structure, especially in small-statured vegetation. PMID:23435053

  16. Micro-patterning and characterization of PHEMA-co-PAM-based optical chemical sensors for lab-on-a-chip applications

    PubMed Central

    Zhu, Haixin; Zhou, Xianfeng; Su, Fengyu; Tian, Yanqing; Ashili, Shashanka; Holl, Mark R.; Meldrum, Deirdre R.

    2012-01-01

    We report a novel method for wafer level, high throughput optical chemical sensor patterning, with precise control of the sensor volume and capability of producing arbitrary microscale patterns. Monomeric oxygen (O2) and pH optical probes were polymerized with 2-hydroxyethyl methacrylate (HEMA) and acrylamide (AM) to form spin-coatable and further crosslinkable polymers. A micro-patterning method based on micro-fabrication techniques (photolithography, wet chemical process and reactive ion etch) was developed to miniaturize the sensor film onto glass substrates in arbitrary sizes and shapes. The sensitivity of fabricated micro-patterns was characterized under various oxygen concentrations and pH values. The process for spatially integration of two sensors (Oxygen and pH) on the same substrate surface was also developed, and preliminary fabrication and characterization results were presented. To the best of our knowledge, it is the first time that poly (2-hydroxylethyl methacrylate)-co-poly (acrylamide) (PHEMA-co-PAM)-based sensors had been patterned and integrated at the wafer level with micron scale precision control using microfabrication techniques. The developed methods can provide a feasible way to miniaturize and integrate the optical chemical sensor system and can be applied to any lab-on-a-chip system, especially the biological micro-systems requiring optical sensing of single or multiple analytes. PMID:23175599

  17. Self-organizing wireless sensor networks for structural health monitoring

    NASA Astrophysics Data System (ADS)

    Basheer, Mohammed R.; Rao, Vittal S.; Derriso, Mark M.

    2003-07-01

    A smart sensor node has been developed which has (a) the ability to sense strain of the structure under observation, (b) process this raw sensor data in cooperation with its neighbors and (c) transmit the information to the end user. This network is designed to be self organizing in the sense of establishing and maintaining the inter node connectivity without the need for human intervention. For the envisioned application of structural health monitoring, wireless communication is the most practical solution for node interconnectivity not only because they eliminate interconnecting cables but also for their ability to establish communication links even in inaccessible regions. But wireless nework brings with it a number of issues such as interference, fault tolerant self organizing, multi-hop communication, energy effieiciency, routing and finally reliable operation in spite of massive complexity of the sysetm. This paper addresses the issue of fault tolerant self organiing in wireless sensor networks. We propose a new architecture called the Redundant Tree Network (RTN). RTN is a hierarchical network which exploits redundant links between nodes to provide reliability.

  18. Structural behavior of concrete box bridge using embedded FBG sensors

    NASA Astrophysics Data System (ADS)

    Chung, Wonseok; Kang, Donghoon

    2012-04-01

    For the structural monitoring of railway bridges, electromagnetic interference (EMI) is a significant problem as modern railway lines are powered by high-voltage electric power feeding systems. Fiber optic sensing systems are free from EMI and have been successfully applied in civil engineering fields. This study presents the application of fiber Bragg grating (FBG)-based sensing systems to precast concrete box railway bridges. A 20 m long full-scale precast concrete box railway girder was fabricated and tested in order to identify its static performance. The experimental program involved the measurement of the nonlinear static behavior until failure. Multiplexed FBG strain sensors were embedded along the length of steel rebar and a strain-induced wavelength shift was measured in order to monitor internal strains. The measured values from the FBG-based sensors are compared with the results using electric signal-based sensors. The results show that the FBG sensing system is promising and can improve the efficiency of structural monitoring for modern railway bridges.

  19. Structural interactions of a voltage sensor toxin with lipid membranes

    PubMed Central

    Mihailescu, Mihaela; Krepkiy, Dmitriy; Milescu, Mirela; Gawrisch, Klaus; Swartz, Kenton J.; White, Stephen

    2014-01-01

    Protein toxins from tarantula venom alter the activity of diverse ion channel proteins, including voltage, stretch, and ligand-activated cation channels. Although tarantula toxins have been shown to partition into membranes, and the membrane is thought to play an important role in their activity, the structural interactions between these toxins and lipid membranes are poorly understood. Here, we use solid-state NMR and neutron diffraction to investigate the interactions between a voltage sensor toxin (VSTx1) and lipid membranes, with the goal of localizing the toxin in the membrane and determining its influence on membrane structure. Our results demonstrate that VSTx1 localizes to the headgroup region of lipid membranes and produces a thinning of the bilayer. The toxin orients such that many basic residues are in the aqueous phase, all three Trp residues adopt interfacial positions, and several hydrophobic residues are within the membrane interior. One remarkable feature of this preferred orientation is that the surface of the toxin that mediates binding to voltage sensors is ideally positioned within the lipid bilayer to favor complex formation between the toxin and the voltage sensor. PMID:25453087

  20. Structural interactions of a voltage sensor toxin with lipid membranes.

    PubMed

    Mihailescu, Mihaela; Krepkiy, Dmitriy; Milescu, Mirela; Gawrisch, Klaus; Swartz, Kenton J; White, Stephen

    2014-12-16

    Protein toxins from tarantula venom alter the activity of diverse ion channel proteins, including voltage, stretch, and ligand-activated cation channels. Although tarantula toxins have been shown to partition into membranes, and the membrane is thought to play an important role in their activity, the structural interactions between these toxins and lipid membranes are poorly understood. Here, we use solid-state NMR and neutron diffraction to investigate the interactions between a voltage sensor toxin (VSTx1) and lipid membranes, with the goal of localizing the toxin in the membrane and determining its influence on membrane structure. Our results demonstrate that VSTx1 localizes to the headgroup region of lipid membranes and produces a thinning of the bilayer. The toxin orients such that many basic residues are in the aqueous phase, all three Trp residues adopt interfacial positions, and several hydrophobic residues are within the membrane interior. One remarkable feature of this preferred orientation is that the surface of the toxin that mediates binding to voltage sensors is ideally positioned within the lipid bilayer to favor complex formation between the toxin and the voltage sensor. PMID:25453087

  1. A hierarchical structure approach to MultiSensor Information Fusion

    SciTech Connect

    Maren, A.J.; Pap, R.M.; Harston, C.T.

    1989-12-31

    A major problem with image-based MultiSensor Information Fusion (MSIF) is establishing the level of processing at which information should be fused. Current methodologies, whether based on fusion at the pixel, segment/feature, or symbolic levels, are each inadequate for robust MSIF. Pixel-level fusion has problems with coregistration of the images or data. Attempts to fuse information using the features of segmented images or data relies an a presumed similarity between the segmentation characteristics of each image or data stream. Symbolic-level fusion requires too much advance processing to be useful, as we have seen in automatic target recognition tasks. Image-based MSIF systems need to operate in real-time, must perform fusion using a variety of sensor types, and should be effective across a wide range of operating conditions or deployment environments. We address this problem through developing a new representation level which facilitates matching and information fusion. The Hierarchical Scene Structure (HSS) representation, created using a multilayer, cooperative/competitive neural network, meets this need. The MSS is intermediate between a pixel-based representation and a scene interpretation representation, and represents the perceptual organization of an image. Fused HSSs will incorporate information from multiple sensors. Their knowledge-rich structure aids top-down scene interpretation via both model matching and knowledge-based,region interpretation.

  2. A hierarchical structure approach to MultiSensor Information Fusion

    SciTech Connect

    Maren, A.J. . Space Inst.); Pap, R.M.; Harston, C.T. )

    1989-01-01

    A major problem with image-based MultiSensor Information Fusion (MSIF) is establishing the level of processing at which information should be fused. Current methodologies, whether based on fusion at the pixel, segment/feature, or symbolic levels, are each inadequate for robust MSIF. Pixel-level fusion has problems with coregistration of the images or data. Attempts to fuse information using the features of segmented images or data relies an a presumed similarity between the segmentation characteristics of each image or data stream. Symbolic-level fusion requires too much advance processing to be useful, as we have seen in automatic target recognition tasks. Image-based MSIF systems need to operate in real-time, must perform fusion using a variety of sensor types, and should be effective across a wide range of operating conditions or deployment environments. We address this problem through developing a new representation level which facilitates matching and information fusion. The Hierarchical Scene Structure (HSS) representation, created using a multilayer, cooperative/competitive neural network, meets this need. The MSS is intermediate between a pixel-based representation and a scene interpretation representation, and represents the perceptual organization of an image. Fused HSSs will incorporate information from multiple sensors. Their knowledge-rich structure aids top-down scene interpretation via both model matching and knowledge-based,region interpretation.

  3. Modeling and Reconstruction of Micro-structured 3D Chitosan/Gelatin Porous Scaffolds Using Micro-CT

    NASA Astrophysics Data System (ADS)

    Gong, Haibo; Li, Dichen; He, Jiankang; Liu, Yaxiong; Lian, Qin; Zhao, Jinna

    2008-09-01

    Three dimensional (3D) channel networks are the key to promise the uniform distribution of nutrients inside 3D hepatic tissue engineering scaffolds and prompt elimination of metabolic products out of the scaffolds. 3D chitosan/gelatin porous scaffolds with predefined internal channels were fabricated and a combination of light microscope, laser confocal microscopy and micro-CT were employed to characterize the structure of porous scaffolds. In order to evaluate the flow field distribution inside the micro-structured 3D scaffolds, a computer reconstructing method based on Micro-CT was proposed. According to this evaluating method, a contrast between 3D porous scaffolds with and without predefined internal channels was also performed to assess scaffolds' fluid characters. Results showed that the internal channel of the 3D scaffolds formed the 3D fluid channel network; the uniformity of flow field distribution of the scaffolds fabricated in this paper was better than the simple porous scaffold without micro-fluid channels.

  4. Development of Micro Air Vehicle Technology With In-Flight Adaptive-Wing Structure

    NASA Technical Reports Server (NTRS)

    Waszak, Martin R. (Technical Monitor); Shkarayev, Sergey; Null, William; Wagner, Matthew

    2004-01-01

    This is a final report on the research studies, "Development of Micro Air Vehicle Technology with In-Flight Adaptrive-Wing Structure". This project involved the development of variable-camber technology to achieve efficient design of micro air vehicles. Specifically, it focused on the following topics: 1) Low Reynolds number wind tunnel testing of cambered-plate wings. 2) Theoretical performance analysis of micro air vehicles. 3) Design of a variable-camber MAV actuated by micro servos. 4) Test flights of a variable-camber MAV.

  5. Obstructive micro diffracting structures as an alternative to plasmonics nano slits for making efficient microlenses.

    PubMed

    Vitrant, Guy; Zaiba, Soraya; Vineeth, Benyamin Y; Kouriba, Timothe; Ziane, Omar; Stéphan, Olivier; Bosson, Jocelyne; Baldeck, Patrice L

    2012-11-19

    Miniature optical components at the wavelength scale remain today a theoretically opened challenging problem of great technological interest. Appart from refractive micro-optics, plasmonics have been proposed to realize micro lenses with properly designed planar metallic nano-patterns. We show in this paper that efficient light focusing at the diffraction limit with higher transmission can be obtained with micro-structures much easier to fabricate than nano ones, such as a simple micro-slit studied here as an example. Optical properties are attributed to diffraction and a quantitative excellent agreement between experiment and theory is obtained.

  6. Micro-fluidics and integrated optics glass sensor for in-line micro-probing of nuclear samples

    SciTech Connect

    Schimpf, A.; Bucci, D.; Broquin, J.E.; Canto, F.; Magnaldo, A.; Couston, L.

    2012-08-15

    We study the miniaturization of Thermal Lens Spectrometry (TLS) towards Lab-on-chip integration in order to reduce the volume of fluid assays in nuclear process control. TLS is of great interest in this context since it combines the advantages of optical detection methods with an inherent suitability for small-scale samples. After validating the experimental principle in a classical thermal lens crossed-beam setup, we show the integration of a Young-interferometer with a microcapillary on a glass substrate, reducing the necessary sample size to 400 nl. The interferometer translates the photo-thermally induced refractive index change in the fluid to a phase shift of the fringe pattern, which can then be detected by a camera. Measurements of Co(II) in ethanol yield a detection limit of c = 5 x 10{sup -4} M for the crossed-beam setup and c = 6 x 10{sup -3} M for the integrated sensor. At an interaction length of 10 m, it detects a minimum absorbance of K = 1.2 x 10{sup -4} in a probed volume of 14 pl. (authors)

  7. From Micro to Nano: The Evolution of Wireless Sensor-Based Health Care.

    PubMed

    Sarkar, Subhadeep; Misra, Sudip

    2016-01-01

    Over the past decade, embedded systems and microelectromechanical systems have evolved in a radical way, redefining our standard of living and enhancing the quality of life. Health care, among various other fields, has benefited vastly from this technological development. The concept of using sensors for health care purposes originated in the late 1980s when sensors were developed to measure certain physiological parameters associated with the human body. In traditional sensor nodes, the signal sources are mostly different environmental phenomena (such as temperature, vibration, and luminosity) or man-made events (such as intrusion and mobile target tracking), whereas in case of the physiological sensors, the signal source is living human tissue. These sensor nodes, as their primary sensing element, have a diaphragm that converts pressure into displacement. This displacement, in turn, is subsequently transformed into an electrical signal. The concept of wireless physiological sensor nodes, however, gained popularity in the mid-2000s, with the sensed data from the nodes transmitted to the hub via a wireless medium. The network formed by this heterogeneous set of wireless body sensor nodes is termed a wireless body-area network (WBAN). Each WBAN is essentially a composition of multiple wireless body sensor nodes and a single hub. The hub is primarily responsible for acquisition of the raw sensed data from all the component sensor nodes and first-level aggregation of the data before transmitting the aggregated data for further analysis to a remote data acquisition center. Here, we outline the evolution of WBANs in the context of modern health care and its convergence with nanotechnology.

  8. From Micro to Nano: The Evolution of Wireless Sensor-Based Health Care.

    PubMed

    Sarkar, Subhadeep; Misra, Sudip

    2016-01-01

    Over the past decade, embedded systems and microelectromechanical systems have evolved in a radical way, redefining our standard of living and enhancing the quality of life. Health care, among various other fields, has benefited vastly from this technological development. The concept of using sensors for health care purposes originated in the late 1980s when sensors were developed to measure certain physiological parameters associated with the human body. In traditional sensor nodes, the signal sources are mostly different environmental phenomena (such as temperature, vibration, and luminosity) or man-made events (such as intrusion and mobile target tracking), whereas in case of the physiological sensors, the signal source is living human tissue. These sensor nodes, as their primary sensing element, have a diaphragm that converts pressure into displacement. This displacement, in turn, is subsequently transformed into an electrical signal. The concept of wireless physiological sensor nodes, however, gained popularity in the mid-2000s, with the sensed data from the nodes transmitted to the hub via a wireless medium. The network formed by this heterogeneous set of wireless body sensor nodes is termed a wireless body-area network (WBAN). Each WBAN is essentially a composition of multiple wireless body sensor nodes and a single hub. The hub is primarily responsible for acquisition of the raw sensed data from all the component sensor nodes and first-level aggregation of the data before transmitting the aggregated data for further analysis to a remote data acquisition center. Here, we outline the evolution of WBANs in the context of modern health care and its convergence with nanotechnology. PMID:26799723

  9. The effects of weighting function errors on spatial filters for structural control. [sensors for vibration damping

    NASA Technical Reports Server (NTRS)

    Lindner, Douglas K.; Reichard, Karl M.

    1992-01-01

    Distributed-effect sensors, which respond to spatially distributed inputs over a significant gauge length, encompass piezoelectric laminate films, modal-domain optical fiber sensors, and holographic sensors; they can be fabricated with spatially varying sensitivity to a distributed measurand for spatial filtering. Such spatial filters are configurable to extract various structural parameters from distributed measurements that cannot be directly measured by sensors. A modeling is presently conducted for distributed-effect sensors' integration into state-space structural models, noting the effects of fabrication errors on sensor operation.

  10. Economic sensor/actuator selection and its application to flexible structure control

    NASA Astrophysics Data System (ADS)

    Skelton, Robert E.; Li, Faming

    2004-07-01

    A systematic design method is proposed for the selecting of actuators and sensors in the structural control in order to minimize the instrumental cost. With actuators and sensors placed at all the admissible locations initially, an iterative minimization algorithm is carried out to identify the sensor/actuator that requires the least precision. By deleting the roughest sensor/actuator each time till loss of feasibility, one can conclude simultaneously the necessary number and type of sensor/actuator, and the location and precision for each sensor/actuator. A tensegrity structure example has been solved as an application of the proposed algorithm.

  11. Design and manufacturing of an array of micro IPMC hair-like sensors

    NASA Astrophysics Data System (ADS)

    Akle, Barbar J.; Tawk, Charbel; Challita, Elio

    2016-04-01

    Ionic Polymer Metal Composites (IPMCs) are known to be compliant, reliable and able to produce a large current when deformed under a wide range of frequencies. In a previous study, our group demonstrated that cylindrical IPMC hair-like transducers can be used as mechano-electrical sensors. In this paper we characterize the sensing performance of the IPMC hair-like sensor and present methodologies on how to increase its sensitivity while reducing its size. Furthermore an array of 4 hair-cell sensors is built and characterized for tactile sensing texture detection.

  12. Micro- and Nanostructured Metal Oxide Chemical Sensors for Volatile Organic Compounds

    NASA Technical Reports Server (NTRS)

    Alim, M. A.; Penn, B. G.; Currie, J. R., Jr.; Batra, A. K.; Aggarwal, M. D.

    2008-01-01

    Aeronautic and space applications warrant the development of chemical sensors which operate in a variety of environments. This technical memorandum incorporates various kinds of chemical sensors and ways to improve their performance. The results of exploratory investigation of the binary composite polycrystalline thick-films such as SnO2-WO3, SnO2-In2O3, SnO2-ZnO for the detection of volatile organic compound (isopropanol) are reported. A short review of the present status of the new types of nanostructured sensors such as nanobelts, nanorods, nanotube, etc. based on metal oxides is presented.

  13. Nanoparticle-Structured Highly Sensitive and Anisotropic Gauge Sensors.

    PubMed

    Zhao, Wei; Luo, Jin; Shan, Shiyao; Lombardi, Jack P; Xu, Yvonne; Cartwright, Kelly; Lu, Susan; Poliks, Mark; Zhong, Chuan-Jian

    2015-09-16

    The ability to tune gauge factors in terms of magnitude and orientation is important for wearable and conformal electronics. Herein, a sensor device is described which is fabricated by assembling and printing molecularly linked thin films of gold nanoparticles on flexible microelectrodes with unusually high and anisotropic gauge factors. A sharp difference in gauge factors up to two to three orders of magnitude between bending perpendicular (B(⊥)) and parallel (B(||)) to the current flow directions is observed. The origin of the unusual high and anisotropic gauge factors is analyzed in terms of nanoparticle size, interparticle spacing, interparticle structure, and other parameters, and by considering the theoretical aspects of electron conduction mechanism and percolation pathway. A critical range of resistivity where a very small change in strain and the strain orientation is identified to impact the percolation pathway in a significant way, leading to the high and anisotropic gauge factors. The gauge anisotropy stems from molecular and nanoscale fine tuning of interparticle properties of molecularly linked nanoparticle assembly on flexible microelectrodes, which has important implication for the design of gauge sensors for highly sensitive detection of deformation in complex sensing environment or on complex curved surfaces such as wearable electronics and skin sensors.

  14. Flexible and waterproof micro-sensors to uncover zebrafish circadian rhythms: The next generation of cardiac monitoring for drug screening.

    PubMed

    Zhang, Xiaoxiao; Beebe, Tyler; Jen, Nelson; Lee, Chia-An; Tai, Yuchong; Hsiai, Tzung K

    2015-09-15

    Flexible electronics are the next generation of sensors for mobile health and implantation. Zebrafish (Danio rerio) is an emergent strategy for pre-clinical drug development and toxicity testing. To address the confounding effects from sedation of fish and removal from the aquatic habitat for micro-electrocardiogram (µECG) measurements, we developed waterproof and wearable sensors to uncover the circadian variation in heart rate (HR) and heart rate variability (HRV) (Massin et al., 2000). The parylene-C based ECG sensor consisted of an ultra-soft silicone integrated jacket designed to wrap around the fish during swimming. The Young's modulus of this silicone jacket matched with the fish surface, and an extended parylene cable connected the underwater chest electrodes with the out-of water electronics. In addition, embedded micro-glass spheres in the silicone effectively reduced the effective density of the jacket to ~1 g cm(-3). These innovations enabled physiological ECG telemetry in the fish's natural habitat without the need for sedation. Furthermore, a set of non-linear signal processing techniques filtered out the breathing and electromagnetic artifacts from the recorded signals. We observed a reduction in mean HR and an increase in HRV over 24h at 10 dpa, accompanied by QT prolongation as well as diurnal variations, followed by normalization in mean HR and QT intervals at 26 days post ventricular amputation (dpa). We revealed Amiodarone-mediated QTc prolongation, HR reduction and HRV increase otherwise masked by sedation. The novel features of the flexible silicon jacket for µECG telemetry unraveled the biological clock and normalization of QT intervals at 26 dpa, providing the first evidence of new physiological phenomena during cardiac injury and repair as well as cardiac drug-mediated aberrant rhythms. Thus, the light weight and waterproof design holds promise to advance the next generation of mobile health and drug discovery. PMID:25909335

  15. A two-dimensional flow sensor with integrated micro thermal sensing elements and a back propagation neural network.

    PubMed

    Que, Ruiyi; Zhu, Rong

    2013-01-01

    This paper demonstrates a novel flow sensor with two-dimensional 360° direction sensitivity achieved with a simple structure and a novel data fusion algorithm. Four sensing elements with roundabout wires distributed in four quadrants of a circle compose the sensor probe, and work in constant temperature difference (CTD) mode as both Joule heaters and temperature detectors. The magnitude and direction of a fluid flow are measured by detecting flow-induced temperature differences among the four elements. The probe is made of Ti/Au thin-film with a diameter of 2 mm, and is fabricated using micromachining techniques. When a flow goes through the sensor, the flow-induced temperature differences are detected by the sensing elements that also serve as the heaters of the sensor. By measuring the temperature differences among the four sensing elements symmetrically distributed in the sensing area, a full 360° direction sensitivity can be obtained. By using a BP neural network to model the relationship between the readouts of the four sensor elements and flow parameters and execute data fusion, the magnitude and direction of the flow can be deduced. Validity of the sensor design was proven through both simulations and experiments. Wind tunnel experimental results show that the measurement accuracy of the airflow speed reaches 0.72 m/s in the range of 3 m/s-30 m/s and the measurement accuracy of flow direction angle reaches 1.9° in the range of 360°.

  16. A Two-Dimensional Flow Sensor with Integrated Micro Thermal Sensing Elements and a Back Propagation Neural Network

    PubMed Central

    Que, Ruiyi; Zhu, Rong

    2014-01-01

    This paper demonstrates a novel flow sensor with two-dimensional 360° direction sensitivity achieved with a simple structure and a novel data fusion algorithm. Four sensing elements with roundabout wires distributed in four quadrants of a circle compose the sensor probe, and work in constant temperature difference (CTD) mode as both Joule heaters and temperature detectors. The magnitude and direction of a fluid flow are measured by detecting flow-induced temperature differences among the four elements. The probe is made of Ti/Au thin-film with a diameter of 2 mm, and is fabricated using micromachining techniques. When a flow goes through the sensor, the flow-induced temperature differences are detected by the sensing elements that also serve as the heaters of the sensor. By measuring the temperature differences among the four sensing elements symmetrically distributed in the sensing area, a full 360° direction sensitivity can be obtained. By using a BP neural network to model the relationship between the readouts of the four sensor elements and flow parameters and execute data fusion, the magnitude and direction of the flow can be deduced. Validity of the sensor design was proven through both simulations and experiments. Wind tunnel experimental results show that the measurement accuracy of the airflow speed reaches 0.72 m/s in the range of 3 m/s–30 m/s and the measurement accuracy of flow direction angle reaches 1.9° in the range of 360°. PMID:24385032

  17. A new control structure to reduce time delay of tracking sensors by applying an angular position sensor.

    PubMed

    Yadegar, Meysam; Karami, Farzaneh; Nobari, Jafar H

    2016-07-01

    In this paper, a new tracking control structure is proposed to decrease the time-delay effect of tracking sensor. To achieve this purpose, an angular position sensor, which generally exists in tracking systems, is used together with the tracking sensor. Also, a compensator is designed and applied to a system with time-delay in order to obtain a behavior same as a system without time-delay. Relying only on tracking sensor may lead to reduce the tracking speed and to increase tracking error. However, it is shown that by using the proposed reformative structure, the speed of tracking and the tracking error can be compensated significantly. In the next step, the performance of the new structure in two cases of constant time-delay and variable time-delay are evaluated and their stability conditions are analyzed. Finally, robustness of the proposed structure is analyzed.

  18. Nano-based sensor for assessment of weaponry structural degradation

    NASA Astrophysics Data System (ADS)

    Brantley, Christina L.; Edwards, Eugene; Ruffin, Paul B.; Kranz, Michael

    2016-04-01

    Missiles and weaponry-based systems are composed of metal structures that can degrade after prolonged exposure to environmental elements. A particular concern is accumulation of corrosion that generally results from prolonged environmental exposure. Corrosion, defined as the unintended destruction or deterioration of a material due to its interaction with the environment, can negatively affect both equipment and infrastructure. System readiness and safety can be reduced if corrosion is not detected, prevented and managed. The current corrosion recognition methods (Visual, Radiography, Ultrasonics, Eddy Current, and Thermography) are expensive and potentially unreliable. Visual perception is the most commonly used method for determining corrosion in metal. Utilization of an inductance-based sensor system is being proposed as part of the authors' research. Results from this research will provide a more efficient, economical, and non-destructive sensing approach. Preliminary results demonstrate a highly linear degradation within a corrosive environment due to the increased surface area available on the sensor coupon. The inductance of the devices, which represents a volume property of the coupon, demonstrated sensitivity to corrosion levels. The proposed approach allows a direct mass-loss measurement based on the change in the inductance of the coupon when placed in an alternating magnetic field. Prototype devices have demonstrated highly predictable corrosion rates that are easily measured using low-power small electronic circuits and energy harvesting methods to interrogate the sensor. Preliminary testing demonstrates that the device concept is acceptable and future opportunities for use in low power embedded applications are achievable. Key results in this paper include the assessment of typical Army corrosion cost, degradation patterns of varying metal materials, and application of wireless sensors elements.

  19. Truss structure integrity identification using PZT sensor-actuator

    SciTech Connect

    Sun, F.P.; Chaudhry, Z.; Liang, C.; Rogers, C.A.

    1994-12-31

    This paper presents a frequency domain impedance-signature-based technique for health monitoring of an assembled truss structure. Unlike conventional modal analysis approaches, the technique uses piezoceramic (PZT) elements as integrated sensor-actuators for acquisition of signature pattern of the truss. The concept of the localization of sensing/actuation area for damage detection of an assembled structure is presented for the first time. Through a PZT patch bonded to a truss node and the measurement of its electric admittance, which is coupled with the mechanical impedance of the truss, the signature pattern of a truss is monitored. The admittance of a truss in question is compared with that of the original healthy truss. Statistic algorithm is then applied to extract a damage index of the truss based on the signature pattern difference. Experimental proof that over a selected band, the detection range of a bonded PZT sensor on a truss is highly constrained to its immediate neighborhood is presented. This characteristic allows accurate determination of the damage location in a complex real-world structure with a minimum mathematical modeling and numerical computation.

  20. Sensor systems for monitoring maglev guideway structures. Final report

    SciTech Connect

    Berthold, J.W.; Bower, J.R.; Buttram, J.D.; Okes, L.R.; Robertson, M.O.

    1992-07-01

    The report is an assessment of the technologies available for continuous monitoring of the physical condition and structural integrity of maglev guideways. The detection of obstructions on the guideway is not included. No particular guideway design is assumed, other than that the largest part of the system will consist of repetitive reinforced concrete structures, probably elevated, that are aligned with close tolerances. It is assumed that the guideway is to be monitored for the correct alignment of the sections, any unusual vibrations or motions, detection of catastrophic failure, and possibly accumulation of ice and snow. The technologies covered are acoustic emission monitoring (a passive acoustic method of listening for crack growth or other unusual structure borne sound), infrared and visible light monitoring (ranging from cameras to displacement sensors), ultrasonics (for vibration, displacement, snow and ice), microwave monitors (for vibration and displacement sensors), and fiber optics (for networks of strain gauges). It is the conclusion of the report that the technologies described are sufficiently mature to meet the requirements. Any particular application will certainly need development, and some may need extensive development, but the basic capabilities are there.

  1. Angularly sensitive wide field of view micro-sensor construction and new processing paradigm: task oriented optical processing

    NASA Astrophysics Data System (ADS)

    Franck, Jerome B.

    2007-04-01

    Discussed is a novel method of manufacturing an Angularly Sensitive Micro-Sensor (ASMS). The process employed utilizes excimer laser ablation to write out the microlens on the curved surface of the master lens. This master lens element is manufactured with fused optical fibers, such that if the registration is maintained, the light from each microlens goes via the fiber to a specific pixel in a focal plane array (FPA). Such a system allows for a field of view greatly in excess of 180 degrees. If local imaging is required for specific tasks the fiber can send the angularly localized image to a pixel set. Image fusing may then be required. Infrared and ultraviolet versions can be manufactured. A more general application allows for a multi-spectral sensor. After one ASMS is constructed, then an inverse mask (mould) can be created and the monolithic sphere, retaining its registration, is covered in liquid plastic and placed into the mould and the exact replica is re-created. The advantage is low cost and rapid manufacture of the ASMS. The paper focuses on this sensor as a Task-Oriented Optical Processing (TOP) system; where the processing is performed primarily by the optics leaving a greatly reduced requirement for an electronic processor. This is a critical issue for micro, insect sized platforms where the weight budget is devoted to the energy and propulsive systems. An important aspect of this approach is that the sensor samples amplitude and angular space rather than amplitude and position space as conventional sensors currently do. This makes the ASMS processing paradigm completely different from conventional image processing. For example using several fiber/pixel elements to comprise a UV polarimeter allows for simple storage and processing of vector elements for simple navigation. The home position may be treated as "Look up table" reference matrix (RM). That base table can be modified to account for the passage of time (and hence change in solar position from

  2. Development of BBD Adding-Delay Architecture for Ultrasonic Micro Array Sensor

    NASA Astrophysics Data System (ADS)

    Tanaka, Tsunehisa; Mo, Yaowu; Tsuchitani, Akira; Inoue, Koji; Arita, Shigeru; Suzuki, Yoshihiko; Yamashita, Kaoru; Okuyama, Masanori

    Bucket Brigade Device (BBD) adding-delay architecture was proposed as the analog beamformer for piezoelectric micromachined ultrasonic sensor phased array. BBD adding-delay architecture were used both as delay and adding elements, and the input signals were distributed adding in the process of delay. This architecture was useful to reduce chip area, simplify system design, and realize on-chip integration. Combining piezoelectric micromachined ultrasonic array sensors and the analog delay-sum circuits successfully performed two-dimensional object detection.

  3. Autostereoscopy-based three-dimensional on-machine measuring system for micro-structured surfaces.

    PubMed

    Li, Da; Cheung, Chi Fai; Ren, Mingjun; Zhou, Liqiu; Zhao, Xing

    2014-10-20

    Traditional off-line measuring systems find it difficult to measure micro-structured workpieces which have a large volume and heavy weight, such as micro-structured patterned precision roller drums. This paper proposes an autostereoscopy-based three-dimensional (3D) measuring method and develops an innovative measuring system for the 3D on-machine measurement of the micro-structured surfaces, an Autostereoscopy-based Three-Dimensional On-machine Measuring (ATDOM) system. The ATDOM system is compact and capable of fast data acquisition and high accuracy in 3D computational reconstruction of complex surfaces under different measuring environments. A prototype ATDOM system is experimentally verified through a series of measurement experiments conducted on a precision machine tool. The results indicate that the ATDOM system provides an important means for efficient and reliable on-machine measurement of micro-structured surfaces. PMID:25401597

  4. Loss of superhydrophobicity of hydrophobic micro/nano structures during condensation.

    PubMed

    Jo, HangJin; Hwang, Kyung Won; Kim, DongHyun; Kiyofumi, Moriyama; Park, Hyun Sun; Kim, Moo Hwan; Ahn, Ho Seon

    2015-04-23

    Condensed liquid behavior on hydrophobic micro/nano-structured surfaces is a subject with multiple practical applications, but remains poorly understood. In particular, the loss of superhydrophobicity of hydrophobic micro/nanostructures during condensation, even when the same surface shows water-repellant characteristics when exposed to air, requires intensive investigation to improve and apply our understanding of the fundamental physics of condensation. Here, we postulate the criterion required for condensation to form from inside the surface structures by examining the grand potentials of a condensation system, including the properties of the condensed liquid and the conditions required for condensation. The results imply that the same hydrophobic micro/nano-structured surface could exhibit different liquid droplet behavior depending on the conditions. Our findings are supported by the observed phenomena: the initiation of a condensed droplet from inside a hydrophobic cavity, the apparent wetted state changes, and the presence of sticky condensed droplets on the hydrophobic micro/nano-structured surface.

  5. A Phase-tracking Snow Micro-structure Model

    NASA Astrophysics Data System (ADS)

    Slaughter, A. E.; Zabaras, N.

    2012-12-01

    Utilizing a methodology derived from models for phase transitions in alloy solidification [1], a 3D finite element (FE) model for snow metamorphism was developed. Avalanches are known to occur due to the existence of a weak-layer of faceted crystals, which form due to temperature gradients within the snow through a process known as kinetic metamorphism [2]. In general, snow models are limited in their ability to model these microstructural changes, especially in three dimensions, and rely on effective properties. To enhance the tools available to avalanche researchers a finite element model was developed capable of tracking vapor deposition within the snow. This is accomplished using a fixed-domain, stabilized finite element solution for the energy, mass, momentum, and transport equations. Using a level-set parameter the domain is separated into either solid or fluid components and along the phase-change boundary a "mushy-zone" is establish [1, 3]. This zone is modeled as porous media that includes the effects of shrinkage and density changes [1]. The basis of the model is the open-source C++ libMesh FE library, as such the model includes adaptive mesh coarsening and refinement and relies on domain decomposition for optimum parallel performance. This work is the initial phase of an ongoing research project that aims to demonstrate the ability to model snow at the micro-structural level and move away from the common coarse, effective property modeling techniques. It will serve as the deterministic basis for a multi-scale, stochastic model of snow that will account for uncertainties such as poorly understood growth properties and measurement variability. Future applications may include the inclusion of liquid melt and include external forces, yielding a comprehensive thermo-mechanical model that could evolve and fracture. [1] D. Samanta, N. Zabaras (2005), Modelling convection in solidification processes using stabilized finite element techniques, J. Numer. Meth. Eng

  6. Heat treatment giving a stable high temperature micro-structure in cast austenitic stainless steel

    DOEpatents

    Anton, Donald L.; Lemkey, Franklin D.

    1988-01-01

    A novel micro-structure developed in a cast austenitic stainless steel alloy and a heat treatment thereof are disclosed. The alloy is based on a multicomponent Fe-Cr-Mn-Mo-Si-Nb-C system consisting of an austenitic iron solid solution (.gamma.) matrix reinforced by finely dispersed carbide phases and a heat treatment to produce the micro-structure. The heat treatment includes a prebraze heat treatment followed by a three stage braze cycle heat treatment.

  7. Research in manufacturing of micro-structured injection molded polymer parts

    NASA Astrophysics Data System (ADS)

    Lucyshyn, Thomas; Struklec, Tobias; Burgsteiner, Martin; Graninger, Georg; Holzer, Clemens

    2015-12-01

    An overview of current research results is given for the topic of injection molding of micro-structured polymer parts regarding filling behavior and demolding process of micro-structures as well as the production of micro-structures on curved surfaces. In order to better understand how micro-structures are formed during the filling stage of injection molding, a study was performed on a test part with micro-channels placed parallely and perpendicularly to flow direction. Short shots with a highly fluent Polypropylene grade were injection molded with the melt front stopping in the structure fields. The melt and mold temperature, the injection rate as well as the use of a variotherm heating system were varied in a systematic Design of Experiments. The shape of the flow front was investigated with the optical measurement system Alicona InfiniteFocus. The data gained was analyzed with Matlab scripts and provided the needed distance to completely fill the structures as a reference value. The next topic covers the demolding step, which is a crucial process step in injection molding of micro-structured parts as the successfully replicated structures often get destroyed in the following demolding step. In order to evaluate the influence of the four aspects polymer, mold surface (coatings), structure (geometry and placement) and process settings on the demolding behavior, an injection mold with integrated measurement system was built, which makes it possible to measure the demolding force respectively a demolding energy under process conditions. These values can be used to quantitatively compare the impact of the above mentioned influencing factors on demolding. Finally, a concept to produce micro-structures on curved surfaces with injection molding is shown: A flat metal premaster structure is used to produce an elastomeric polymer (dimethylsiloxane) master in a casting process. This master is fixed in a conventional injection mold and a thermoplastic polymer is replicated

  8. Sensor-less force-reflecting macro-micro telemanipulation systems by piezoelectric actuators.

    PubMed

    Amini, H; Farzaneh, B; Azimifar, F; Sarhan, A A D

    2016-09-01

    This paper establishes a novel control strategy for a nonlinear bilateral macro-micro teleoperation system with time delay. Besides position and velocity signals, force signals are additionally utilized in the control scheme. This modification significantly improves the poor transparency during contact with the environment. To eliminate external force measurement, a force estimation algorithm is proposed for the master and slave robots. The closed loop stability of the nonlinear micro-micro teleoperation system with the proposed control scheme is investigated employing the Lyapunov theory. Consequently, the experimental results verify the efficiency of the new control scheme in free motion and during collision between the slave robot and the environment of slave robot with environment, and the efficiency of the force estimation algorithm. PMID:27329852

  9. Sensor-less force-reflecting macro-micro telemanipulation systems by piezoelectric actuators.

    PubMed

    Amini, H; Farzaneh, B; Azimifar, F; Sarhan, A A D

    2016-09-01

    This paper establishes a novel control strategy for a nonlinear bilateral macro-micro teleoperation system with time delay. Besides position and velocity signals, force signals are additionally utilized in the control scheme. This modification significantly improves the poor transparency during contact with the environment. To eliminate external force measurement, a force estimation algorithm is proposed for the master and slave robots. The closed loop stability of the nonlinear micro-micro teleoperation system with the proposed control scheme is investigated employing the Lyapunov theory. Consequently, the experimental results verify the efficiency of the new control scheme in free motion and during collision between the slave robot and the environment of slave robot with environment, and the efficiency of the force estimation algorithm.

  10. Test Structures for Rapid Prototyping of Gas and Pressure Sensors

    NASA Technical Reports Server (NTRS)

    Buehler, M.; Cheng, L. J.; Martin, D.

    1996-01-01

    A multi-project ceramic substrate was used in developing a gas sensor and pressure sensor. The ceramic substrate cantained 36 chips with six variants including sensors, process control monitors, and an interconnect ship. Tha gas sensor is being developed as an air quality monitor and the pressure gauge as a barometer.

  11. The zeroes of controlled structures - Sensor/actuator attributes and structural modelling

    NASA Technical Reports Server (NTRS)

    Fleming, Farla M.; Crawley, Edward F.

    1991-01-01

    The effects of sensor/actuator design and modeling decisions on the zero frequencies of single input single output structural systems are explored. A zero definition based on the high gain closed loop character of the poles of a system is used to study parametrically zeroes as a function of sensor and actuator location. An infinite order model is adopted so that the effects of finite order modeling are removed. Examples focus on point or localized actuators and sensors and simple uniform structures. The sensitivity of the zero frequencies to changes in the sensor and actuator location for both collocated and non-collocated cases are presented. Non-minimum phase behavior is visible in only certain non-collocated situations. In addition to the sensor/actuator attributes, the zeroes are shown to be a function of the truncation and discretization used to model the structural response for collocated and dual systems. Methods for improving the zero predictions in the control bandwidth are suggested.

  12. The fabrication of a micro-spiral structure using EDM deposition in the air

    NASA Astrophysics Data System (ADS)

    Chi, Guanxin; Wang, Zhenlong; Xiao, K.; Cui, Jingzhi; Jin, Baidong

    2008-03-01

    A novel micromachining method to deposit a micro-3D spiral structure in air using electrical discharge machining (EDM) with a brass electrode was presented. During the deposition process, a 3D spiral structure is obtained only by the feed of the z-axis in the vertical direction. Furthermore, the obtained structure can be formed and repeated stably even in the upside-down direction under a gravity environment. It is seen that the material components of a micro-spiral structure are almost the same as those of an electrode by the energy spectrum analysis of a micro-spiral structure. According to scanning electron microscope photographs, the micro-spiral appears to feature a layered material organism structure and has compact bonding with the body material. In order to understand the forming mechanism of this kind of micro-spiral structure, simulation analysis is conducted. The track of the deposition particles can be obtained by simulation, which determines the shape of the deposited structure. According to the simulation results, the track of the deposition particles is consistent with that of EDM experiments. It is further found that the distribution of the electromagnetic field in a discharge channel has an important influence on the deposited structure and the track of the deposition particles.

  13. Self-assembled and highly selective sensors based on air-bridge-structured nanowire junction arrays.

    PubMed

    Park, Won Jeong; Choi, Kyung Jin; Kim, Myung Hwa; Koo, Bon Hyeong; Lee, Jong-Lam; Baik, Jeong Min

    2013-08-14

    We describe a strategy for creating an air-bridge-structured nanowire junction array platform that capable of reliably discriminating between three gases (hydrogen, carbon monoxide, and nitrogen dioxide) in air. Alternatively driven dual nanowire species of ZnO and CuO with the average diameter of ∼30 nm on a single substrate are used and decorated with metallic nanoparticles to form two-dimensional microarray, which do not need to consider the post fabrications. Each individual nanowires in the array form n-n, p-p, and p-n junctions at the micro/nanoscale on single substrate and the junctions act as electrical conducting path for carriers. The adsorption of gas molecules to the surface changes the potential barrier height formed at the junctions and the carrier transport inside the straight semiconductors, which provide the ability of a given sensor array to differentiate among the junctions. The sensors were tested for their ability to distinguish three gases (H2, CO, and NO2), which they were able to do unequivocally when the data was classified using linear discriminant analysis. PMID:23841667

  14. Characterization of irregularly micro-structured surfaces related to their wetting properties

    NASA Astrophysics Data System (ADS)

    Li, Ping; Xie, Jin; Deng, Zhenjie

    2015-04-01

    It is difficult to control a surface wetting due to the random surface texture, but its fabrication is easy. Hence, the volume ratio is proposed through the 3D characterization of micro-structured surface in contrast to traditional roughness factor, fractal dimension and aspect ratio through 2D characterization. The objective is to investigate the wetting properties related to the characterization of irregularly micro-structured surface. First, the irregularly micro-structured Si surfaces with 0.22-3.58 μm in depth were machined by the rubbing, the polishing and the grinding with different diamond abrasive grain size and random abrasive grain shape, respectively; secondly, the surface wetting properties were investigated with regard to the characterized parameters of measured micro-topographic surfaces; finally, the irregular wetting model was constructed by using volume ratio on the base of non-composite wetting. It is shown that the contact angle increases with increasing roughness factor and aspect ratio and decreasing fractal dimension on the irregularly micro-structured surfaces, but it is different from the prediction of non-composite wetting model. Moreover, the irregularly micro-structured surfaces without anisotropic properties produce smaller contact angles than regularly micro-structured surfaces with anisotropic properties. The experimental results show that an increase in volume ratio leads to a decrease in contact angle. It is identical to the predictions of the proposed model. This is because the volume ratio precisely illustrates 3D contact information between the liquid and solid interfaces. It is confirmed that the volume ratio may be utilized to predict and control the wetting of irregularly micro-structured surface.

  15. A tactile sensor using a conductive graphene-sponge composite.

    PubMed

    Chun, Sungwoo; Hong, Ahyoung; Choi, Yeonhoi; Ha, Chunho; Park, Wanjun

    2016-04-28

    For sensors that emulate human tactile perception, we suggest a simple method for fabricating a highly sensitive force sensor using a conductive polyurethane sponge where graphene flakes are self-assembled into the porous structure of the sponge. The complete sensor device shows a sensitive and reliable detection response for a broad range of pressure and dynamic pressure that correspond to human tactile perception. Sensitivity of the sensor to detect vibration is also confirmed with vertical actuations due to slipping over micro-scale ridge structures attached on the sensors. Based on the sensor's ability to detect both pressure and vibration, the sensor can be utilized as a flexible tactile sensor. PMID:27076360

  16. A tactile sensor using a conductive graphene-sponge composite.

    PubMed

    Chun, Sungwoo; Hong, Ahyoung; Choi, Yeonhoi; Ha, Chunho; Park, Wanjun

    2016-04-28

    For sensors that emulate human tactile perception, we suggest a simple method for fabricating a highly sensitive force sensor using a conductive polyurethane sponge where graphene flakes are self-assembled into the porous structure of the sponge. The complete sensor device shows a sensitive and reliable detection response for a broad range of pressure and dynamic pressure that correspond to human tactile perception. Sensitivity of the sensor to detect vibration is also confirmed with vertical actuations due to slipping over micro-scale ridge structures attached on the sensors. Based on the sensor's ability to detect both pressure and vibration, the sensor can be utilized as a flexible tactile sensor.

  17. Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications

    PubMed Central

    Di Sante, Raffaella

    2015-01-01

    In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS) have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques. PMID:26263987

  18. Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications.

    PubMed

    Di Sante, Raffaella

    2015-01-01

    In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS) have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques.

  19. Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications.

    PubMed

    Di Sante, Raffaella

    2015-01-01

    In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS) have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques. PMID:26263987

  20. Special sensors for deformation measurements of different construction materials and structures

    NASA Astrophysics Data System (ADS)

    Glisic, Branko; Inaudi, Daniele; Kronenberg, Pascal; LLoret, Sandra; Vurpillot, Samuel

    1999-05-01

    SOFO is a fiber optic sensor system that allows the monitoring of micrometer deformations over measurement bases up to a few meters. It is particularly adapted to measure civil structures built with conventional civil engineering materials (concrete, steel and timber). It has been successfully tested in different types of structures such as bridges, tunnels and piles. The application of the system is however limited in some case when unusual materials are used in the construction and in other cases by the dimensions of standard SOFO sensors. To extend the domain of application of the current system, special sensors have been developed. In this paper we present four special SOFO sensors: long, membrane, thin and stiff sensors. The long sensor has a measurement basis of several tenths of meters and its purpose is the measurement of deformations in massive and large structures (dames, tunnels). The membrane sensor is for use on laminated materials (e.g. membrane roofing) and it is easy to install by simply gluing it to the structure to be monitored. Since standard sensors can not be used for thin mortar layers because of their cross- section, a thin sensor has been developed, too. Finally, the aim of the stiff sensor is to determine the hardening (solidification) time of concrete. This time is determined by comparing the deformations of a stiff and a standard sensor, closely placed in the concrete at the very early age. The design of these sensors is presented along with significant application examples.

  1. Microwave-assisted synthesis of II-VI semiconductor micro-and nanoparticles towards sensor applications

    NASA Astrophysics Data System (ADS)

    Majithia, Ravish Yogesh

    Engineering particles at the nanoscale demands a high degree of control over process parameters during synthesis. For nanocrystal synthesis, solution-based techniques typically include application of external convective heat. This process often leads to slow heating and allows decomposition of reagents or products over time. Microwave-assisted heating provides faster, localized heating at the molecular level with near instantaneous control over reaction parameters. In this work, microwave-assisted heating has been applied for the synthesis of II-VI semiconductor nanocrystals namely, ZnO nanopods and CdX (X = Se, Te) quantum dots (QDs). Based on factors such as size, surface functionality and charge, optical properties of such nanomaterials can be tuned for application as sensors. ZnO is a direct bandgap semiconductor (3.37 eV) with a large exciton binding energy (60 meV) leading to photoluminescence (PL) at room temperature. A microwave-assisted hydrothermal approach allows the use of sub-5 nm ZnO zero-dimensional nanoparticles as seeds for generation of multi-legged quasi one-dimensional nanopods via heterogeneous nucleation. ZnO nanopods, having individual leg diameters of 13-15 nm and growing along the [0001] direction, can be synthesized in as little as 20 minutes. ZnO nanopods exhibit a broad defect-related PL spanning the visible range with a peak at ~615 nm. Optical sensing based on changes in intensity of the defect PL in response to external environment (e.g., humidity) is demonstrated in this work. Microwave-assisted synthesis was also used for organometallic synthesis of CdX(ZnS) (X = Se, Te) core(shell) QDs. Optical emission of these QDs can be altered based on their size and can be tailored to specific wavelengths. Further, QDs were incorporated in Enhanced Green-Fluorescent Protein -- Ultrabithorax (EGFP-Ubx) fusion protein for the generation of macroscale composite protein fibers via hierarchal self-assembly. Variations in EGFP- Ubx˙QD composite

  2. RNA Secondary Structure Modulates FMRP's Bi-Functional Role in the MicroRNA Pathway.

    PubMed

    Kenny, Phillip; Ceman, Stephanie

    2016-01-01

    MicroRNAs act by post-transcriptionally regulating the gene expression of 30%-60% of mammalian genomes. MicroRNAs are key regulators in all cellular processes, though the mechanism by which the cell activates or represses microRNA-mediated translational regulation is poorly understood. In this review, we discuss the RNA binding protein Fragile X Mental Retardation Protein (FMRP) and its role in microRNA-mediated translational regulation. Historically, FMRP is known to function as a translational suppressor. However, emerging data suggests that FMRP has both an agonistic and antagonistic role in regulating microRNA-mediated translational suppression. This bi-functional role is dependent on FMRP's interaction with the RNA helicase Moloney leukemia virus 10 (MOV10), which modifies the structural landscape of bound mRNA, therefore facilitating or inhibiting its association with the RNA-Induced Silencing Complex. PMID:27338369

  3. Replicating micro-optical structures using soft embossing technique

    NASA Astrophysics Data System (ADS)

    Shang, Xiaobing; Tan, Jin-Yi; De Smet, Jelle; Joshi, Pankaj; Islamaj, Esma; Cuypers, Dieter; Vervaeke, Michael; Van Erps, Jürgen; Thienpont, Hugo; De Smet, Herbert

    2014-10-01

    In this article we report the fabrication of large arrays of micro-optical gratings using soft embossing with elastic Polydimethylsiloxane (PDMS) molds and ultra-violet (UV) curable resins. Three different kinds of resins are used to replicate the master gratings in a process akin to a roll to roll process. The optical surface profiling measurements show that the dimensions of the replicated gratings closely approximate those of the master gratings. Optical diffractions of these gratings are also measured and analyzed.

  4. 2D tilting MEMS micro mirror integrating a piezoresistive sensor position feedback

    NASA Astrophysics Data System (ADS)

    Lani, S.; Bayat, D.; Despont, M.

    2015-02-01

    An integrated position sensor for a dual-axis electromagnetic tilting mirror is presented. This tilting mirror is composed of a silicon based mirror directly assembled on a silicon membrane supported by flexible beams. The position sensors are constituted by 4 Wheatstone bridges of piezoresistors which are fabricated by doping locally the flexible beams. A permanent magnet is attached to the membrane and the scanner is mounted above planar coils deposited on a ceramic substrate to achieve electromagnetic actuation. The performances of the piezoresistive sensors are evaluated by measuring the output signal of the piezoresistors as a function of the tilt of the mirror and the temperature. White light interferometry was performed for all measurement to measure the exact tilt angle. The minimum detectable angle with such sensors was 30µrad (around 13bits) in the range of the minimum resolution of the interferometer. The tilt reproducibility was 0.0186%, obtained by measuring the tilt after repeated actuations with a coil current of 50mA during 30 min and the stability over time was 0.05% in 1h without actuation. The maximum measured tilt angle was 6° (mechanical) limited by nonlinearity of the MEMS system.

  5. Visualization and Analysis of Wireless Sensor Network Data for Smart Civil Structure Applications Based On Spatial Correlation Technique

    NASA Astrophysics Data System (ADS)

    Chowdhry, Bhawani Shankar; White, Neil M.; Jeswani, Jai Kumar; Dayo, Khalil; Rathi, Manorma

    2009-07-01

    Disasters affecting infrastructure, such as the 2001 earthquakes in India, 2005 in Pakistan, 2008 in China and the 2004 tsunami in Asia, provide a common need for intelligent buildings and smart civil structures. Now, imagine massive reductions in time to get the infrastructure working again, realtime information on damage to buildings, massive reductions in cost and time to certify that structures are undamaged and can still be operated, reductions in the number of structures to be rebuilt (if they are known not to be damaged). Achieving these ideas would lead to huge, quantifiable, long-term savings to government and industry. Wireless sensor networks (WSNs) can be deployed in buildings to make any civil structure both smart and intelligent. WSNs have recently gained much attention in both public and research communities because they are expected to bring a new paradigm to the interaction between humans, environment, and machines. This paper presents the deployment of WSN nodes in the Top Quality Centralized Instrumentation Centre (TQCIC). We created an ad hoc networking application to collect real-time data sensed from the nodes that were randomly distributed throughout the building. If the sensors are relocated, then the application automatically reconfigures itself in the light of the new routing topology. WSNs are event-based systems that rely on the collective effort of several micro-sensor nodes, which are continuously observing a physical phenomenon. WSN applications require spatially dense sensor deployment in order to achieve satisfactory coverage. The degree of spatial correlation increases with the decreasing inter-node separation. Energy consumption is reduced dramatically by having only those sensor nodes with unique readings transmit their data. We report on an algorithm based on a spatial correlation technique that assures high QoS (in terms of SNR) of the network as well as proper utilization of energy, by suppressing redundant data transmission

  6. Vibration sensing in flexible structures using a distributed-effect modal domain optical fiber sensor

    NASA Technical Reports Server (NTRS)

    Reichard, Karl M.; Lindner, Douglas K.; Claus, Richard O.

    1991-01-01

    Modal domain optical fiber sensors have recently been employed in the implementation of system identification algorithms and the closed-loop control of vibrations in flexible structures. The mathematical model of the modal domain optical fiber sensor used in these applications, however, only accounted for the effects of strain in the direction of the fiber's longitudinal axis. In this paper, we extend this model to include the effects of arbitrary stress. Using this sensor model, we characterize the sensor's sensitivity and dynamic range.

  7. Phase structure development as preheating UHMWPE powder temperature changes in the micro-UPM process

    NASA Astrophysics Data System (ADS)

    Liang, Xiong; Wu, Xiaoyu; Xu, Bin; Ma, Jiang; Liu, Zhiyuan; Peng, Taijiang; Fu, Lianyu

    2016-01-01

    In this study, using high-speed mechanical drilling on printed circuit boards (PCBs) with two micro carbide drill bits with diameters of 0.15 mm and 0.20 mm, two different PCB micro-cylinder array inserts are fabricated using the micro-ultrasonic powder moulding (micro-UPM) process. According to the temperature curves recorded by a measurement module, when viscoelastic heating dominated, the temperature increasing rate was about three times the rate when interfacial friction heating dominated. From the differential scanning calorimetry and nanoindentation test results, if the ultra-high molecule weight polyethylene (UHMWPE) powder was not preheated, then the micro-cylinder array polymer parts generally consisted of nascent and melt-recrystallised phases as a whole. However, when the micro-cavity and compressed UHMWPE powder grew from room temperature of 28 °C to 85 °C, the two-phase structure gradually developed into a single melt-recrystallised phase. According to single-crystal x-ray diffraction test results, the crystallinity of the base region of the micro-UPM cylinder array part is higher than that of the micro-cylinder region, whereas the grain size of the (1 1 0) crystal surface is larger than that of the (2 0 0) crystal surface.

  8. Fabrication of micro/nano hierarchical structures with analysis on the surface mechanics

    NASA Astrophysics Data System (ADS)

    Jheng, Yu-Sheng; Lee, Yeeu-Chang

    2016-10-01

    Biomimicry refers to the imitation of mechanisms and features found in living creatures using artificial methods. This study used optical lithography, colloidal lithography, and dry etching to mimic the micro/nano hierarchical structures covering the soles of gecko feet. We measured the static contact angle and contact angle hysteresis to reveal the behavior of liquid drops on the hierarchical structures. Pulling tests were also performed to measure the resistance of movement between the hierarchical structures and a testing plate. Our results reveal that hierarchical structures at the micro-/nano-scale are considerably hydrophobic, they provide good flow characteristics, and they generate more contact force than do surfaces with micro-scale cylindrical structures.

  9. Fiber optic sensors for process monitoring of composite aerospace structures

    NASA Astrophysics Data System (ADS)

    Menendez Martin, Jose M.; Munoz-Esquer, Pedro; Rodriguez-Lence, Fernando; Guemes, J. Alfredo

    2002-07-01

    There are currently available many software tools for modeling the processing of composite materials, that help designers to evaluate the process constraints and the feasibility of different concepts. Nevertheless, several manufacturing tests are still required for adjustment of the control parameters before production may start. Real time monitoring is the only way to validate the numerical results and to get a deeper knowledge on the process evolution. Final objective would be a closed loop known as 'Intelligent Material Processing'.: process model - in situ sensors - predictive control, able to react on real time to small disturbances, adapting the process parameters for optimal results. This paper concentrates on the sensor development for two aerospace processes, autoclave curing and RTM, and it present the results obtained on a real aircraft structural part, a five meter diameter frame for the fuselage of Airbus A380 . An optical fiber system has been implemented to monitor the movement of the resin flow front during the injection and the internal residual strains. The procedure has the advantage of being very robust, and it may be used for complex geometry of the part. It has been demonstrated the feasibility of the procedure to work at an industrial environment; the results are being used to refine the data on the material properties, as the preform permeability, and to improve the process control.

  10. Optical fiber Fabry-Perot sensors for smart structures

    NASA Astrophysics Data System (ADS)

    Lee, C. E.; Alcoz, J. J.; Yeh, Y.; Gibler, W. N.; Atkins, R. A.; Taylor, H. F.

    1992-06-01

    The paper describes the operation principles and the construction, performance, and application of optical fiber Fabry-Perot interferometers (FFPIs) utilizing internal mirrors, developed for sensing temperature, strain, acoustic waves, and other physical perturbations in structural materials. It is shown that the internal-mirror FFPI sensors have a good mechanical strength which make it possible for the sensors to endure mechanical stresses experienced during the embedding process, and provide high sensitivity and point-sensing and ultrasound pressure. A digital signal processor is described. the 29th International Conference on the Applications of the Mössbauer Effect (ICAME 2007) held in Kanpur, India, 14-19 October 2007, PART IV/VII 30 2008 11 19 2008 11 18 2008 7 2008 Springer Science+Business Media B.V. 2008 9819 10.1007/s10751-008-9819-1 17 57Fe-Mössbauer study of electrically conducting barium iron vanadate glass after heat treatment 115 121 2008 9 17 2008 10 9 Spr

  11. Pore- and micro-structural characterization of a novel structural binder based on iron carbonation

    SciTech Connect

    Das, Sumanta; Stone, David; Convey, Diana; Neithalath, Narayanan

    2014-12-15

    The pore- and micro-structural features of a novel binding material based on the carbonation of waste metallic iron powder are reported in this paper. The binder contains metallic iron powder as the major ingredient, followed by additives containing silica and alumina to facilitate favorable reaction product formation. Compressive strengths sufficient for a majority of concrete applications are attained. The material pore structure is investigated primarily through mercury intrusion porosimetry whereas electron microscopy is used for microstructural characterization. Reduction in the overall porosity and the average pore size with an increase in carbonation duration from 1 day to 4 days is noticed. The pore structure features are used in predictive models for gas and moisture transport (water vapor diffusivity and moisture permeability) through the porous medium which dictates its long-term durability when used in structural applications. Comparisons of the pore structure with those of a Portland cement paste are also provided. The morphology of the reaction products in the iron-based binder, and the distribution of constituent elements in the microstructure are also reported. - Highlights: • Carbonation of iron produces a dense microstructure. • Pore volume in iron carbonate lower, critical size higher than those in OPC pastes • Reaction product contains iron, carbon, silicon, aluminum and calcium. • Power-law for porosity-moisture permeability relationship was established.

  12. Piezo impedance sensors to monitor degradation of biological structure

    NASA Astrophysics Data System (ADS)

    Annamdas, Kiran Kishore Kumar; Annamdas, Venu Gopal Madhav

    2010-04-01

    In some countries it is common to have wooden structures in their homes, especially Japan. However, metals and its alloys are the most widely used engineering materials in construction of any military or civil structure. Re-visiting natural disasters like the recent Haiti earthquake (12 Jan 2010) or Katrina (cyclones) reminds the necessity to have better housing infrastructure with robust monitoring systems. Traditionally wood (green material) was accepted as excellent rehabilitation material, after any disaster. In recent times, the recycling materials extracted from inorganic, biodegradable wastes are converted into blocks or sheets, and are also used to assist public in rehabilitation camps. The key issue which decreases the life of these rehabilitated structure including green materials (like wood) is unnecessary degradation or deterioration over time due to insect or acid attack or rain/ice fall. The recycling material also needs monitoring to protect them against acid or rain/ice attacks. Thus, a few health monitoring techniques have emerged in the recent past. Electromechanical Impedance technique is one such technique, which is simple but robust to detect variations in the integrity of structures. In this paper, impedance based piezoceramic sensor was bonded on wooden sample, which was subjected to degradation in presence of acids. Variations in mass of plank are studied.

  13. Impedance based sensor technology to monitor stiffness of biological structures

    NASA Astrophysics Data System (ADS)

    Annamdas, Venu Gopal Madhav; Annamdas, Kiran Kishore Kumar

    2010-04-01

    In countries like USA or Japan it is not so uncommon to have wooden structures in their homes. However, metals and its alloys are the most widely used engineering materials in construction of any military or civil structure. Revisiting natural disasters like the recent Haiti earthquake (12 Jan 2010) or Katrina (cyclones) reminds the necessity to have better housing infrastructure with robust monitoring systems. Traditionally wood is accepted as excellent rehabilitation material, after any disaster. The recycling materials extracted from in-organic, biodegradable wastes, also can be used for rehabilitation. The key issue which dampens the life of these rehabilitated structure including green materials (like wood) is unnecessary deposits (nails, screws, bolts etc)/damages due to insect attack. Thus, a few health monitoring techniques have emerged in the recent past. Electromechanical Impedance technique is one such technique, which is simple but robust to detect variations in the integrity of structures. In this paper, impedance based piezoceramic sensor was bonded on wooden sample, which was used to study changes due to metallic (steel nails) deposits at various locations. A study of weight deposits on aluminum plate was used for comparisons.

  14. Monolithic carbon structures including suspended single nanowires and nanomeshes as a sensor platform

    NASA Astrophysics Data System (ADS)

    Lim, Yeongjin; Heo, Jeong-Il; Madou, Marc; Shin, Heungjoo

    2013-11-01

    With the development of nanomaterial-based nanodevices, it became inevitable to develop cost-effective and simple nanofabrication technologies enabling the formation of nanomaterial assembly in a controllable manner. Herein, we present suspended monolithic carbon single nanowires and nanomeshes bridging two bulk carbon posts, fabricated in a designed manner using two successive UV exposure steps and a single pyrolysis step. The pyrolysis step is accompanied with a significant volume reduction, resulting in the shrinkage of micro-sized photoresist structures into nanoscale carbon structures. Even with the significant elongation of the suspended carbon nanowire induced by the volume reduction of the bulk carbon posts, the resultant tensional stress along the nanowire is not significant but grows along the wire thickness; this tensional stress gradient and the bent supports of the bridge-like carbon nanowire enhance structural robustness and alleviate the stiction problem that suspended nanostructures frequently experience. The feasibility of the suspended carbon nanostructures as a sensor platform was demonstrated by testing its electrochemical behavior, conductivity-temperature relationship, and hydrogen gas sensing capability.

  15. Digital laser printing of aluminum micro-structure on thermally sensitive substrates

    NASA Astrophysics Data System (ADS)

    Zenou, Michael; Sa'ar, Amir; Kotler, Zvi

    2015-05-01

    Aluminum metal is of particular interest for use in printed electronics due to its low cost, high conductivity and low migration rate in electrically driven organic-based devices. However, the high reactivity of Al particles at the nano-scale is a major obstacle in preparing stable inks from this metal. We describe digital printing of aluminum micro-structures by laser-induced forward transfer in a sub-nanosecond pulse regime. We manage to jet highly stable molten aluminum micro-droplets with very low divergence, less than 2 mrad, from 500 nm thin metal donor layers. We analyze the micro-structural properties of the print geometry and their dependence on droplet volume, print gap and spreading. High quality printing of aluminum micro-patterns on plastic and paper is demonstrated.

  16. Micro-manufacturing of micro-scale porous surface structures for enhanced heat transfer applications: an experimental process optimization study

    NASA Astrophysics Data System (ADS)

    Cora, Ömer N.; Usta, Yusuf; Koç, Muammer

    2009-04-01

    Integrated and compact products necessitate the use of advanced thermal management systems with reduced footprint and cost as well as increased efficiency. Micro-scale, porous and modulated (i.e. channels, pyramids, etc) surfaces offer increased surface area for a given volume and lead to two-phase heat transfer conditions with efficiency enhancements up to 300%. Such surfaces made of copper powders were demonstrated to be quite effective by several researchers after they were produced in controlled lab environments. Similar surfaces made of high temperature resistant materials such as stainless steel, nickel and titanium can also be used in fuel processor, SOFC and PEM fuel cell applications as bipolar/interconnect plates. However, their fabrication under mass-production conditions for marketable and cost-effective products requires well-established process parameters. In this study, warm compaction of copper powders onto thin copper solid substrates was experimented with under different compaction pressure (15-50 MPa), temperature (350-500 °C) and surface geometry (flat, large and small channeled) parameters using a design of experiment (DOE) approach to determine the proper process conditions. Porosity and bonding strength of compacted samples were measured to characterize their feasibility for compact and/or micro-scale heat/mass transfer applications. Results showed that a minimum 350 °C temperature and 15 MPa pressure level is necessary to obtain sound porous and micro-channeled surface layers. It was also found that at higher pressure levels (50 MPa), fabrication of micro-scale surface structures is highly repeatable with enhanced bonding strength characteristics. DOE findings will be used to establish proper process conditions to produce such porous surfaces using a continuous roll compaction process in the future.

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

    NASA Astrophysics Data System (ADS)

    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

  18. Design of a High-Performance Micro Integrated Surface Plasmon Resonance Sensor Based on Silicon-On-Insulator Rib Waveguide Array.

    PubMed

    Yuan, Dengpeng; Dong, Ying; Liu, Yujin; Li, Tianjian

    2015-07-16

    Based on silicon-on-insulator (SOI) rib waveguide with large cross-section, a micro integrated surface plasmon resonance (SPR) biochemical sensor platform is proposed. SPR is excited at the deeply etched facet of the bend waveguide by the guiding mode and a bimetallic configuration is employed. With the advantages of SOI rib waveguide and the silicon microfabrication technology, an array of the SPR sensors can be composed to implement wavelength interrogation of the sensors' output signal, so the spectrometer or other bulky and expensive equipment are not necessary, which enables the SPR sensor to realize the miniaturization and integration of the entire sensing system. The performances of the SPR sensor element are verified by using the two-dimensional finite-different time-domain method. The parameters of the sensor element and the array are optimized for the achievement of high performance for biochemical sensing application. As a typical example, a single bimetallic SPR sensor with 3 nm Au over 32 nm Al possesses a high sensitivity of 3.968 × 104 nm/RIU, a detection-accuracy of 14.7 μm(-1). For a uniparted SPR sensor, it can achieve a detection limit of 5.04 × 10(-7) RIU. With the relative power measurement accuracy of 0.01 dB, the refractive index variation of 1.14 × 10(-5) RIU can be detected by the SPR sensor array.

  19. Design and Analysis of a Single-Camera Omnistereo Sensor for Quadrotor Micro Aerial Vehicles (MAVs) †

    PubMed Central

    Jaramillo, Carlos; Valenti, Roberto G.; Guo, Ling; Xiao, Jizhong

    2016-01-01

    We describe the design and 3D sensing performance of an omnidirectional stereo (omnistereo) vision system applied to Micro Aerial Vehicles (MAVs). The proposed omnistereo sensor employs a monocular camera that is co-axially aligned with a pair of hyperboloidal mirrors (a vertically-folded catadioptric configuration). We show that this arrangement provides a compact solution for omnidirectional 3D perception while mounted on top of propeller-based MAVs (not capable of large payloads). The theoretical single viewpoint (SVP) constraint helps us derive analytical solutions for the sensor’s projective geometry and generate SVP-compliant panoramic images to compute 3D information from stereo correspondences (in a truly synchronous fashion). We perform an extensive analysis on various system characteristics such as its size, catadioptric spatial resolution, field-of-view. In addition, we pose a probabilistic model for the uncertainty estimation of 3D information from triangulation of back-projected rays. We validate the projection error of the design using both synthetic and real-life images against ground-truth data. Qualitatively, we show 3D point clouds (dense and sparse) resulting out of a single image captured from a real-life experiment. We expect the reproducibility of our sensor as its model parameters can be optimized to satisfy other catadioptric-based omnistereo vision under different circumstances. PMID:26861351

  20. Thin films of tetrafluorosubstituted cobalt phthalocyanine: Structure and sensor properties

    NASA Astrophysics Data System (ADS)

    Klyamer, Darya D.; Sukhikh, Aleksandr S.; Krasnov, Pavel O.; Gromilov, Sergey A.; Morozova, Natalya B.; Basova, Tamara V.

    2016-05-01

    In this work, thin films of tetrafluorosubstituted cobalt phthalocyanine (CoPcF4) were prepared by organic molecular beam deposition and their structure was studied using UV-vis, polarization dependent Raman spectroscopy, XRD and atomic force microscopy. Quantum chemical calculations (DFT) have been employed in order to determine the detailed assignment of the bands in the CoPcF4 IR and Raman spectra. The electrical sensor response of CoPcF4 films to ammonia vapours was investigated and compared with that of unsubstituted cobalt phthalocyanine films. In order to explain the difference in sensitivity of the unsubstituted and fluorinated phthalocyanines to ammonia, the nature and properties of chemical binding between CoPc derivatives and NH3 were described by quantum-chemical calculations utilizing DFT method. The effect of post-deposition annealing on surface morphology and gas sensing properties of CoPcF4 films was also studied.

  1. FEM Modeling of a Magnetoelectric Transducer for Autonomous Micro Sensors in Medical Application

    NASA Astrophysics Data System (ADS)

    Yang, Gang; Talleb, Hakeim; Gensbittel, Aurélie; Ren, Zhuoxiang

    2015-11-01

    In the context of wireless and autonomous sensors, this paper presents the multiphysics modeling of an energy transducer based on magnetoelectric (ME) composite for biomedical applications. The study considers the power requirement of an implanted sensor, the communication distance, the size limit of the device for minimal invasive insertion as well as the electromagnetic exposure restriction of the human body. To minimize the electromagnetic absorption by the human body, the energy source is provided by an external reader emitting low frequency magnetic field. The modeling is carried out with the finite element method by solving simultaneously the multiple physics problems including the electric load of the conditioning circuit. The simulation results show that with the T-L mode of a trilayer laminated ME composite, the transducer can deliver the required energy in respecting different constraints.

  2. Micro-encapsulated sensors for in vivo assessment of the oxidative stress in aquatic organisms

    NASA Astrophysics Data System (ADS)

    Sadovoy, Anton; Teh, Cathleen; Escobar, Marco; Meglinski, Igor; Korzh, Vladimir

    2011-10-01

    Oxidative stress results from an imbalance between the production and detoxification of reactive oxygen spices (ROS). ROS are natural byproducts of normal metabolism of oxygen and have important roles in cell signaling and homeostasis. Many heart related diseases like heart failure and myocardial infarction develop as a result of oxidative stress. Current treatment cannot improve the progressive decline in heart function experienced by all patients. Therefore heart failure is the cause of around 25% of all deaths in the Asia Pacific region. Thus any step taken to address the oxidative stress problem is essential for enhancing human health and improve their quality of life. Current approach is dedicated to develop micron-size oxidation stress-sensor for in-vivo measuring level of ROS in KillerRed expressing transgenic zebrafish larvae. Central to our investigation is the light-inducible heart failure animal model we developed in zebrafish that expressed KillerRed in the heart. By utilizing the photosensitizer properties of KillerRed to produce ROS upon green light illumination, heart failure can be repeatedly induced in a non-invasive manner. Importantly, the use of this biological platform permits the development of physiologically sensitive ROS sensor and identifies efficient antioxidants that improve heart contractility. The biosensor approach is based on utilizing biocompatible polyelectrolyte microcapsules as a carry of fluorescent dyes sensitive to amount of reactive oxygen spices. Microcapsule prevents dye diffusion in tissue that makes use toxic dyes possible. Microcapsule's wall is permeable for environment with size less than 500 Da. The oxidation stress-sensors are injected directly in zebrafish pericardium with further circulation along blood system. Detecting of ROS is obtained by using laser scanning microscopy by illuminating oxidation stress-sensors and detecting changing excitation signal from the fluorescent dye.

  3. Micro-encapsulated sensors for in vivo assessment of the oxidative stress in aquatic organisms

    NASA Astrophysics Data System (ADS)

    Sadovoy, Anton; Teh, Cathleen; Escobar, Marco; Meglinski, Igor; Korzh, Vladimir

    2012-03-01

    Oxidative stress results from an imbalance between the production and detoxification of reactive oxygen spices (ROS). ROS are natural byproducts of normal metabolism of oxygen and have important roles in cell signaling and homeostasis. Many heart related diseases like heart failure and myocardial infarction develop as a result of oxidative stress. Current treatment cannot improve the progressive decline in heart function experienced by all patients. Therefore heart failure is the cause of around 25% of all deaths in the Asia Pacific region. Thus any step taken to address the oxidative stress problem is essential for enhancing human health and improve their quality of life. Current approach is dedicated to develop micron-size oxidation stress-sensor for in-vivo measuring level of ROS in KillerRed expressing transgenic zebrafish larvae. Central to our investigation is the light-inducible heart failure animal model we developed in zebrafish that expressed KillerRed in the heart. By utilizing the photosensitizer properties of KillerRed to produce ROS upon green light illumination, heart failure can be repeatedly induced in a non-invasive manner. Importantly, the use of this biological platform permits the development of physiologically sensitive ROS sensor and identifies efficient antioxidants that improve heart contractility. The biosensor approach is based on utilizing biocompatible polyelectrolyte microcapsules as a carry of fluorescent dyes sensitive to amount of reactive oxygen spices. Microcapsule prevents dye diffusion in tissue that makes use toxic dyes possible. Microcapsule's wall is permeable for environment with size less than 500 Da. The oxidation stress-sensors are injected directly in zebrafish pericardium with further circulation along blood system. Detecting of ROS is obtained by using laser scanning microscopy by illuminating oxidation stress-sensors and detecting changing excitation signal from the fluorescent dye.

  4. Propulsion of micro-structures in Oscillatory Stokes Flow

    NASA Astrophysics Data System (ADS)

    Jo, Ikhee; Huang, Yangyang; Zimmerman, Walter; Kanso, Eva

    2015-11-01

    Drug delivery often necessitates specific site-targeting within the human body. The use of micro and/or nano devices swimming through the bloodstream provides an attractive mechanism for targeted drug targeting, however the design and practical implementation of such devices remain very challenging. Inspired by flapping wings, we construct a two-dimensional wedge-like device, consisting of two links connected by a linear torsional spring and released in an oscillatory Stokes flow. We vary the stiffness and rest angle of the linear spring and the oscillation amplitude and frequency of the background flow to explore the behavior of the device. We find that the device achieves a net displacement, or propulsion, in oscillatory flows even when no elastic energy is stored initially, thus breaking Purcell's scallop's theorem. More importantly, the vehicle tends to align with the background flow under perturbations. We conclude by commenting on how to control the parameters of the device and the fluid to achieve desired behavior of the device. These findings may have significant implications on the design of micro devices in viscous fluids.

  5. Development of embedded sensor models in composite laminates for structural health monitoring

    NASA Astrophysics Data System (ADS)

    Kim, Heung S.; Ghoshal, Anindya; Chattopadhyay, Aditi; Prosser, William H.

    2003-08-01

    A new improved nonlinear transient generalized layerwise theory for modeling embedded discrete and continuous sensor(s) outputs in laminated composite plates with acoustic emission from cracks and embedded delaminations is developed. The computational modeling involves development of a finite element scheme using an improved layerwise laminate theory for a composite laminate plate with embedded discrete and continuous sensors and embedded discrete delaminations. The simulated cases studied included cantilever plates with embedded sensors and embedded delamination under low frequency vibration and square plates with discrete embedded sensors and continuous embedded sensor architecture and embedded discrete delaminations under high frequency acoustic emission. The effect on sensor outputs due to scattering of the acoustic emission due to the presence of delamination is also investigated. It is expected that this analytical model would be a useful tool for numerical simulation of composite laminated structures with embedded delaminations and embedded sensor architecture, particularly since experimental investigation could often be prohibitive to simulate different conditions.

  6. Ultraprecision machining of micro-structured functional surfaces on brittle materials

    NASA Astrophysics Data System (ADS)

    Yu, D. P.; Wong, Y. S.; Hong, G. S.

    2011-09-01

    Ultraprecision micro-structured functional surfaces on hard and brittle materials, e.g. ceramic and glass, are gaining increasing application in a range of areas such as engineering optics and semiconductor and biomedical products. However, due to their tendency of being damaged in brittle fracture in machining, it is challenging to achieve both a high surface finish and complex surface shapes. In this paper, ultraprecision machining of micro-structured functional surfaces on brittle materials by fast tool servo diamond turning is studied. A machining model has been developed to ensure ductile regime machining of the brittle material, in which the material is removed by both plastic deformation and brittle fracture, but the cracks produced are prevented from being extended into the finished surface. Based on the model, an iterative numerical method has been proposed to predict the maximum feed rate for producing crack-free micro-structured surfaces. Machining experiments on typical micro-structured functional surfaces have been carried out to validate the effectiveness of the proposed method for producing ultraprecision micro-structured functional surfaces.

  7. Replication of polyethylene nano-micro hierarchical structures using ultrasonic forming

    NASA Astrophysics Data System (ADS)

    Lee, Chi Hoon; Jung, Phill Gu; Lee, Sang Min; Park, Sang Hu; Shin, Bo Sung; Kim, Joon-Ho; Hwang, Kyu-Youn; Kim, Kyoung Min; Ko, Jong Soo

    2010-03-01

    We present the replication of polyethylene (PE) nano-micro hierarchical structures and their application for superhydrophobic surfaces. A commercial ultrasonic welding system was used to apply ultrasonic vibration energy to the forming of nano-micro hierarchical structures. To evaluate ultrasonic formability, Ni nanomold and nano-micro hierarchical mold were designed and fabricated. The optimal weld times were 1.5 s and 3.0 s for PE nanoprotrusions and nano-micro hierarchical structures, respectively. The forming process was conducted at atmospheric pressure. The PE structures were well replicated without a vacuum. The trapped air in the microcavity of the nano-micromold was dispersed and absorbed into the molten PE. Ultrasonic nano-microreplication technology showed an extremely short processing time and did not require a vacuum environment. To investigate the applicability of ultrasonic forming, the fabricated nanoprotrusions and nano-micro hierarchical structures were coated with plasma polymerized fluorocarbon (PPFC) of a hydrophobic nature and were applied to modify superhydrophobic surfaces. The contact angle was increased from 106° (smooth surface) to 125° (nanostructured surface) and finally to 160° (nano-microstructured surface) so that the surface became superhydrophobic.

  8. Structural health monitoring system of soccer arena based on optical sensors

    NASA Astrophysics Data System (ADS)

    Shishkin, Victor V.; Churin, Alexey E.; Kharenko, Denis S.; Zheleznova, Maria A.; Shelemba, Ivan S.

    2014-05-01

    A structural health monitoring system based on optical sensors has been developed and installed on the indoor soccer arena "Zarya" in Novosibirsk. The system integrates 119 fiber optic sensors: 85 strain, 32 temperature and 2 displacement sensors. In addition, total station is used for measuring displacement in 45 control points. All of the constituents of the supporting structure are subjects for monitoring: long-span frames with under floor ties, connections, purlins and foundation.

  9. Suppression of secondary electron yield by micro-porous array structure

    NASA Astrophysics Data System (ADS)

    Ye, M.; He, Y. N.; Hu, S. G.; Wang, R.; Hu, T. C.; Yang, J.; Cui, W. Z.

    2013-02-01

    We study secondary electron yield (SEY) suppression for metal materials using a roughened surface with a micro-porous array. First, we perform a Monte Carlo simulation of the electron trajectory in a single cylindrical well using a phenomenological model of secondary electron emission and the SEY suppression efficiency of a micro-porous array. The simulation results show that the SEY of a roughened surface is affected significantly by the aspect ratio of the micro-pores and the surface porosity of the metal plate. Then, to verify the simulation results, we produce a micro-porous array on metal plates using photolithography and measure their SEYs. We show that the micro-porous array structure can efficiently suppress the SEY of metal materials, and the measurements agree quantitatively with the corresponding simulation results. Finally, we derive an analytical formula to evaluate easily the SEY suppression efficiency of the Ag micro-porous array. In total, the micro-porous array proposed in this paper offers an alternative to SEY suppression in related areas such as multipactor effects in satellite payloads or electron cloud effects in accelerators.

  10. Suppression of secondary electron yield by micro-porous array structure

    SciTech Connect

    Ye, M.; He, Y. N.; Hu, S. G.; Wang, R.; Hu, T. C.; Yang, J.; Cui, W. Z.

    2013-02-21

    We study secondary electron yield (SEY) suppression for metal materials using a roughened surface with a micro-porous array. First, we perform a Monte Carlo simulation of the electron trajectory in a single cylindrical well using a phenomenological model of secondary electron emission and the SEY suppression efficiency of a micro-porous array. The simulation results show that the SEY of a roughened surface is affected significantly by the aspect ratio of the micro-pores and the surface porosity of the metal plate. Then, to verify the simulation results, we produce a micro-porous array on metal plates using photolithography and measure their SEYs. We show that the micro-porous array structure can efficiently suppress the SEY of metal materials, and the measurements agree quantitatively with the corresponding simulation results. Finally, we derive an analytical formula to evaluate easily the SEY suppression efficiency of the Ag micro-porous array. In total, the micro-porous array proposed in this paper offers an alternative to SEY suppression in related areas such as multipactor effects in satellite payloads or electron cloud effects in accelerators.

  11. JPL control-structure interaction technology: Micro-precision CSI

    NASA Technical Reports Server (NTRS)

    Laskin, Robert A.

    1991-01-01

    The NASA Control-Structure Interaction (CSI) Program is described in outline and graphic form. Particular emphasis is given to the activities of the Jet Propulsion Lab. The goals of the program are (1) controlled structure performance enhancement, (2) controlled structure unified methods for design/analysis, and (3) ground validation methods for CSI flight systems.

  12. Monitoring of Structural Integrity of Composite Structures by Embedded Optical Fiber Sensors

    NASA Technical Reports Server (NTRS)

    Osei, Albert J.

    2002-01-01

    Real time monitoring of the mechanical integrity and stresses on key aerospace composite structures like aircraft wings, walls of pressure vessels and fuel tanks or any other structurally extended components and panels as in space telescopes is very important to NASA. Future military and commercial aircraft as well as NASA space systems such as Space Based Radar and International Space Station will incorporate a monitoring system to sense any degradation to the structure. In the extreme flight conditions of an aerospace vehicle it might be desirable to measure the strain every ten centimeters and thus fully map out the strain field of a composite component. A series of missions and vehicle health management requirements call for these measurements. At the moment thousands of people support a few vehicle launches per year. This number can be significantly reduced by implementing intelligent vehicles with integral nervous systems (smart structures). This would require maintenance to be performed only as needed. Military and commercial aircrafts have an equally compelling case. Maintenance yearly costs are currently reaching astronomical heights. Monitoring techniques are therefore required that allow for maintenance to be performed only when needed. This would allow improved safety by insuring that necessary tasks are performed while reducing costs by eliminating procedures that are costly and not needed. The advantages fiber optical sensors have over conventional electro-mechanical systems like strain gauges have been widely extolled in the research literature. These advantages include their small size, low weight, immunity to electrical resistance, corrosion resistance, compatibility with composite materials and process conditions, and multiplexing capabilities. One fiber optic device which is suitable for distributed sensing is the fiber Bragg grating (FBG). Researchers at NASA MSFC are currently developing techniques for using FBGs for monitoring the integrity of

  13. Evaluating distributed fibre optic sensors integrated into thermoplastic composites for structural health monitoring

    NASA Astrophysics Data System (ADS)

    Schilder, Constanze; Schukar, Marcus; Steffen, Milan; Krebber, Katerina

    2014-05-01

    Strain sensors used for structural health monitoring (SHM) must provide reliable measurement data during their entire service lifetime. To achieve this for fibre optic sensors integrated into composites, the integration of the sensor has to be adapted according to the process conditions. This paper describes the fabrication of thermoplastic composite samples with integrated distributed fibre optic sensors (DFOS) based on copper-nickel and polyimide coated silica optical fibres. The performance of these DFOS as SHM sensors is evaluated in terms of reliability by measurements derived from comparative measurements with resistance strain gauges and from fatigue tests with 10 million load cycles.

  14. Light diffusing effects of nano and micro-structures on OLED with microcavity.

    PubMed

    Cho, Doo-Hee; Shin, Jin-Wook; Joo, Chul Woong; Lee, Jonghee; Park, Seung Koo; Moon, Jaehyun; Cho, Nam Sung; Chu, Hye Yong; Lee, Jeong-Ik

    2014-10-20

    We examined the light diffusing effects of nano and micro-structures on microcavity designed OLEDs. The results of FDTD simulations and experiments showed that the pillar shaped nano-structure was more effective than the concave micro-structure for light diffusing of microcavity OLEDs. The sharp luminance distribution of the microcavity OLED was changed to near Lambertian luminance distribution by the nano-structure, and light diffusing effects increased with the height of the nano-structure. Furthermore, the nano-structure has advantages including light extraction of the substrate mode, reproducibility of manufacturing process, and minimizing pixel blur problems in an OLED display panel. The nano-structure is a promising candidate for a light diffuser, resolving the viewing angle problems in microcavity OLEDs.

  15. Effects of Micro-structure and Micro-parameters on Brazilian Tensile Strength Using Flat-Joint Model

    NASA Astrophysics Data System (ADS)

    Xu, Xueliang; Wu, Shunchuan; Gao, Yongtao; Xu, Miaofei

    2016-09-01

    It has been widely accepted that tensile strength plays a dominant role in the failure mechanism of rock or rock-like material. Tensile strength is determined mainly via two methods: the direct tension test and Brazilian test. Due to the strictness of preparing the specimen and difficulty of conducting the direct tension test, Brazilian test has been widely applied to determine the tensile strength of geo-materials. However, there is no exact standard for Brazilian test specimen. Moreover, Brazilian tensile strength (BTS) is affected by many factors, such as loading rate, loading platen width, model size. So far, most parametric studies of geo-materials have involved compression tests, but few studies have systematically focused on Brazilian test. The continuum methods have difficulty reproducing the failure process of Brazilian test, and 2D discrete element methods can not reflect the real mechanical behavior of a 3D cylindrical disk specimen. Moreover, the standard bonded-particle model has intrinsic problems in simulating geo-materials. This paper, using a 3D flat-joint model (FJM3D), investigates the effects of micro-structure and micro-parameters on BTS. The micro-structure consists of model size, model resolution, and degree of heterogeneity. The micro-parameters include the average coordination number, crack density, and bond strength. The effects on BTS are summarized, and this summary will be useful for guiding future Brazilian tests. Finally, FJM3D is used to calibrate Brisbane tuff by Brazilian test and the uniaxial compression test. The simulation results are in good agreement with those measured from experiments, and the failure process of Brazilian test is analyzed in detail at the microscale. Because of the heterogeneity of rock, cracks initiate near the loading platen instead of the center of the specimen. Even so, BTS can be an useful tensile index for geo-materials in a triaxial stress state, which is similar to the physical situations, and

  16. Micro-structural integrity of dental enamel subjected to two tooth whitening regimes.

    PubMed

    Tanaka, Reina; Shibata, Yo; Manabe, Atsufumi; Miyazaki, Takashi

    2010-04-01

    Colour modification of tooth enamel has proven successful, but it is unclear how various bleaching applications affect micro-structural integrity of the whitened enamel. To investigate the internal structural integrity of human intact tooth enamel with the application of two commonly used whitening regimes (in-office power bleaching with 35% hydrogen peroxide and home bleaching with 10% carbamide peroxide), evaluations were performed on teeth of identical colour classification. After the bleaching applications, the enamel mineral density was quantified and visualised with micro-computed tomography. The micro-structural differences between the whitened tooth enamel samples were distinctive, though the colour parameter changes within the samples were equivalent. Home bleaching achieved colour modification by demineralisation, whereas in-office bleaching depended on redistribution of the minerals after treatment and subsequent enhanced mineralisation.

  17. Preparation of disk-like particles with micro/nano hierarchical structures.

    PubMed

    Meng, Zhen; Yang, Wenbo; Chen, Pengpeng; Wang, Weina; Jia, Xudong; Xi, Kai

    2013-10-15

    A facile, reproductive method has been successfully developed to produce disk-like microparticles self-assembled from monodispersed hybrid silica nanoparticles under certain circumstance. The disk-like microparticles with micro/nano hierarchical structures could be obtained in large amount under a mild condition and further used to biomimetic design of the superhydrophobic surface of lotus leaf. After traditional surface modification with dodecyltrichlorosiliane, the static contact angle of water on the surface with micro/nano hierarchical structure could reach 168.8°. The method of surface modification could be further simplified by click reaction with the introduction of thiol groups under mild condition. The present strategy for constructing the surface with micro/nano hierarchical structures offers the advantage of simple and large area fabrication, which enables a variety of superhydrophobic applications.

  18. Reading from Scratch - A Vision-System for Reading Data on Micro-structured Surfaces

    NASA Astrophysics Data System (ADS)

    Dragon, Ralf; Becker, Christian; Rosenhahn, Bodo; Ostermann, Jörn

    Labeling and marking industrial manufactured objects gets increasingly important nowadays because of novel material properties and plagiarism. As part of the Collaborative Research Center 653 which investigates micro-structured metallic surfaces for inherent mechanical data storage, we research into a stable and reliable optical readout of the written data. Since this comprises a qualitative surface reconstruction, we use directed illumination to make the micro structures visible. Then we apply a spectral analysis to obtain image partitioning and perform signal tracking enhanced by a customized Hidden Markov Model. In this paper, we derive the algorithms used and demonstrate reading data from a surface with 1.6kbit/cm2 from a micro-structured groove which varies by only 3μ m in depth (thus a “scratch”). We demonstrate the system’s robustness with experiments with real and artificially-rendered surfaces.

  19. Near infrared imaging of micro-structured polymer-metal surface pattern

    NASA Astrophysics Data System (ADS)

    Han, J.; Lee, J.; Lee, T.; Kang, J. U.

    2010-06-01

    Two-dimensional infrared scanning microscopy images of micro-structured surface patterns in an organic transistor device with metal electrode stripes on a polymer channel layer have been demonstrated. A compact single mode optical fiber scanning probe which has a micro dome-shape lens at the tip end was used for the scanning in which reflected beam intensities are coupled back to the optical fiber transceiver depending on the returned power of the sample material. Based on the experiment, the obtained structural dimensions of the micro structure specimen were well matched to the designed ones. These images were compared to the digital microscopy photos for a potential usage to conduct not only the in situ microscopic electrode pattern monitoring of the device but also to non-destructively investigate any surface reflecting material in micrometer scales.

  20. Proton currents constrain structural models of voltage sensor activation

    PubMed Central

    Randolph, Aaron L; Mokrab, Younes; Bennett, Ashley L; Sansom, Mark SP; Ramsey, Ian Scott

    2016-01-01

    The Hv1 proton channel is evidently unique among voltage sensor domain proteins in mediating an intrinsic ‘aqueous’ H+ conductance (GAQ). Mutation of a highly conserved ‘gating charge’ residue in the S4 helix (R1H) confers a resting-state H+ ‘shuttle’ conductance (GSH) in VGCs and Ci VSP, and we now report that R1H is sufficient to reconstitute GSH in Hv1 without abrogating GAQ. Second-site mutations in S3 (D185A/H) and S4 (N4R) experimentally separate GSH and GAQ gating, which report thermodynamically distinct initial and final steps, respectively, in the Hv1 activation pathway. The effects of Hv1 mutations on GSH and GAQ are used to constrain the positions of key side chains in resting- and activated-state VS model structures, providing new insights into the structural basis of VS activation and H+ transfer mechanisms in Hv1. DOI: http://dx.doi.org/10.7554/eLife.18017.001 PMID:27572256

  1. A nanoporous interferometric micro-sensor for biomedical detection of volatile sulphur compounds

    NASA Astrophysics Data System (ADS)

    Kumeria, Tushar; Parkinson, Luke; Losic, Dusan

    2011-12-01

    This work presents the use of nanoporous anodic aluminium oxide [AAO] for reflective interferometric sensing of volatile sulphur compounds and hydrogen sulphide [H2S] gas. Detection is based on changes of the interference signal from AAO porous layer as a result of specific adsorption of gas molecules with sulphur functional groups on a gold-coated surface. A nanoporous AAO sensing platform with optimised pore diameters (30 nm) and length (4 µm) was fabricated using a two-step anodization process in 0.3 M oxalic, followed by coating with a thin gold film (8 nm). The AAO is assembled in a specially designed microfluidic chip supported with a miniature fibre optic system that is able to measure changes of reflective interference signal (Fabry-Perrot fringes). When the sensor is exposed to a small concentration of H2S gas, the interference signal showed a concentration-dependent wavelength shifting of the Fabry-Perot interference fringe spectrum, as a result of the adsorption of H2S molecules on the Au surface and changes in the refractive index of the AAO. A practical biomedical application of reflectometric interference spectroscopy [RIfS] Au-AAO sensor for malodour measurement was successfully shown. The RIfS method based on a nanoporous AAO platform is simple, easy to miniaturise, inexpensive and has great potential for development of gas sensing devices for a range of medical and environmental applications.

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

    NASA Astrophysics Data System (ADS)

    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.

  3. Ultra-low sensitivity to temperature low-cost optical fiber Fabry-Perot micro pressure sensor with a chitosan diaphragm

    NASA Astrophysics Data System (ADS)

    Wang, Wenhua; Li, Sidong; Wen, Lili

    2013-11-01

    In this paper, a low-cost CDEFPI (chitosan diaphragm-based extrinsic Fabry-Perot interferometer) micro pressure sensor with high sensitivity and ultra-low temperature dependence is proposed. The chitosan diaphragm is achieved through crosslinking method via glutaraldehyde which reduces extremely the water swelling property of chitosan and improves greatly the performance of sensor. A vent hole leaving during laser heating fusion bonding process guarantees the ultra-low temperature sensitivity of the sensor. The CDEFPI pressure sensor with a sensitivity of 25.65 nm/kPa (176.86 nm/psi), a resolution of 7.8 Pa (0.001 psi), temperature sensitivity of 0.015 nm/°C, and a thermal induced pressure measurement error limited within 0.0005 kPa/°C (0.00007 psi/°C) has been demonstrated.

  4. A new approach for structural health monitoring by applying anomaly detection on strain sensor data

    NASA Astrophysics Data System (ADS)

    Trichias, Konstantinos; Pijpers, Richard; Meeuwissen, Erik

    2014-03-01

    Structural Health Monitoring (SHM) systems help to monitor critical infrastructures (bridges, tunnels, etc.) remotely and provide up-to-date information about their physical condition. In addition, it helps to predict the structure's life and required maintenance in a cost-efficient way. Typically, inspection data gives insight in the structural health. The global structural behavior, and predominantly the structural loading, is generally measured with vibration and strain sensors. Acoustic emission sensors are more and more used for measuring global crack activity near critical locations. In this paper, we present a procedure for local structural health monitoring by applying Anomaly Detection (AD) on strain sensor data for sensors that are applied in expected crack path. Sensor data is analyzed by automatic anomaly detection in order to find crack activity at an early stage. This approach targets the monitoring of critical structural locations, such as welds, near which strain sensors can be applied during construction and/or locations with limited inspection possibilities during structural operation. We investigate several anomaly detection techniques to detect changes in statistical properties, indicating structural degradation. The most effective one is a novel polynomial fitting technique, which tracks slow changes in sensor data. Our approach has been tested on a representative test structure (bridge deck) in a lab environment, under constant and variable amplitude fatigue loading. In both cases, the evolving cracks at the monitored locations were successfully detected, autonomously, by our AD monitoring tool.

  5. Evaluation and improvement in sensor performance and durability for structural health monitoring systems

    NASA Astrophysics Data System (ADS)

    Blackshire, James L.; Cooney, Adam

    2006-03-01

    For aerospace applications, the successful transition and use of integrated structural health monitoring systems will require durable sensors that can perform in their intended environment for many years. For legacy aircraft the primary means of implementing a sensor system will be through surface mounting or bonding of the sensors to the structure. Previous work has shown that the performance of surface-bonded piezo sensors can degrade due to environmental effects such as vibrations, temperature fluctuations, and substrate flexure motions. This performance degradation included sensor cracking, disbonding, and general loss of efficiency over time. In this activity, the bond and piezo material characteristics of a typical surface-bonded piezo sensor system were studied to understand and improve the long-term durability and survivability of the sensor system. Analytic and computational models were developed and used to understand stress-strain relationships for the bonded sensor system, with a special emphasis being place on coefficient of thermal expansion issues. Accelerated environmental testing was accomplished for simple bonded piezo sensor systems, where a displacement-field imaging technique was used to understand the piezo sensor performance. Future activities will focus on identifying the optimal bond conditions and piezo material type, with the ultimate goal of improving the robustness of health monitoring systems through improved sensor system design and packaging.

  6. Hierarchical periodic micro/nano-structures on nitinol and their influence on oriented endothelialization and anti-thrombosis.

    PubMed

    Nozaki, Kosuke; Shinonaga, Togo; Ebe, Noriko; Horiuchi, Naohiro; Nakamura, Miho; Tsutsumi, Yusuke; Hanawa, Takao; Tsukamoto, Masahiro; Yamashita, Kimihiro; Nagai, Akiko

    2015-12-01

    The applications of hierarchical micro/nano-structures, which possess properties of two-scale roughness, have been studied in various fields. In this study, hierarchical periodic micro/nano-structures were fabricated on nitinol, an equiatomic Ni-Ti alloy, using a femtosecond laser for the surface modification of intravascular stents. By controlling the laser fluence, two types of surfaces were developed: periodic nano- and micro/nano-structures. Evaluation of water contact angles indicated that the nano-surface was hydrophilic and the micro/nano-surface was hydrophobic. Endothelial cells aligned along the nano-structures on both surfaces, whereas platelets failed to adhere to the micro/nano-surface. Decorrelation between the responses of the two cell types and the results of water contact angle analysis were a result of the pinning effect. This is the first study to show the applicability of hierarchical periodic micro/nano-structures for surface modification of nitinol.

  7. Acoustic emission-based sensor analysis and damage classification for structural health monitoring of composite structures

    NASA Astrophysics Data System (ADS)

    Uprety, Bibhisha

    Within the aerospace industry the need to detect and locate impact events, even when no visible damage is present, is important both from the maintenance and design perspectives. This research focused on the use of Acoustic Emission (AE) based sensing technologies to identify impact events and characterize damage modes in composite structures for structural health monitoring. Six commercially available piezoelectric AE sensors were evaluated for use with impact location estimation algorithms under development at the University of Utah. Both active and passive testing were performed to estimate the time of arrival and plate wave mode velocities for impact location estimation. Four sensors were recommended for further comparative investigations. Furthermore, instrumented low-velocity impact experiments were conducted on quasi-isotropic carbon/epoxy composite laminates to initiate specific types of damage: matrix cracking, delamination and fiber breakage. AE signal responses were collected during impacting and the test panels were ultrasonically C-scanned after impact to identify the internal damage corresponding to the AE signals. Matrix cracking and delamination damage produced using more compliant test panels and larger diameter impactor were characterized by lower frequency signals while fiber breakage produced higher frequency responses. The results obtained suggest that selected characteristics of sensor response signals can be used both to determine whether damage is produced during impacting and to characterize the types of damage produced in an impacted composite structure.

  8. Precise rainbow trapping for low-frequency acoustic waves with micro Mie resonance-based structures

    NASA Astrophysics Data System (ADS)

    Zhou, Chen; Yuan, Baoguo; Cheng, Ying; Liu, Xiaojun

    2016-02-01

    We have realized the acoustic rainbow trapping in the low frequency region (200-500 Hz) through micro Mie resonance-based structures. The structure has eight channels with a high refractive index obtained by coiling space, that can excite strong interactions with incident waves and support various orders of multipoles due to the Mie resonances of the microstructure. By utilizing the structure, the precise spatial modulation of the acoustic wave is demonstrated both theoretically and experimentally. The effect of trapping broadband acoustic waves and spatially separating different frequency components are ascribed to the monopolar Mie resonances of the structures. The trapping frequency is derived and the trapping positions can be tuned arbitrarily. With enhanced wave-structure interactions and tailored frequency responses, such micro structures show precise spectral-spatial control of acoustic waves and open a diverse venue for high performance acoustic wave detection, sensing, filtering, and a nondestructive test.

  9. Optical fiber load sensor based on a semi-auxetic structure: a proof of concept

    NASA Astrophysics Data System (ADS)

    Schenato, Luca; Pasuto, Alessandro; Galtarossa, Andrea; Palmieri, Luca

    2016-05-01

    In this work a quasi-distributed optical fiber load sensor based on a semi-auxetic structure is presented. By concatenating sections with positive Poisson's ratio to sections with negative one it is possible to precisely encode the distributed load into a strain exerted on a fiber. The sensor is described and a simple proof of concept is built and tested. The fiber is interrogated by means of optical frequency domain reflectometry. The proposed sensor represents just one example of the potential applications of auxetic and semi-auxetic structures and materials in optical fiber sensors development.

  10. Non-contact passive temperature measuring system and method of operation using micro-mechanical sensors

    SciTech Connect

    2000-04-18

    A non-contact infrared thermometer measures target temperatures remotely without requiring the ratio of the target size to the target distance to the thermometer. A collection means collects and focuses target IR radiation on an IR detector. The detector measures thermal energy of the target over a spectrum using micromechanical sensors. A processor means calculates the collected thermal energy in at least two different spectral regions using a first algorithm in program form and further calculates the ratio of the thermal energy in the at least two different spectral regions to obtain the target temperature independent of the target size, distance to the target and emissivity using a second algorithm in program form.

  11. Non-contact passive temperature measuring system and method of operation using micro-mechanical sensors

    DOEpatents

    Thundat, Thomas G.; Oden, Patrick I.; Datskos, Panagiotis G.

    2000-01-01

    A non-contact infrared thermometer measures target temperatures remotely without requiring the ratio of the target size to the target distance to the thermometer. A collection means collects and focusses target IR radiation on an IR detector. The detector measures thermal energy of the target over a spectrum using micromechanical sensors. A processor means calculates the collected thermal energy in at least two different spectral regions using a first algorithm in program form and further calculates the ratio of the thermal energy in the at least two different spectral regions to obtain the target temperature independent of the target size, distance to the target and emissivity using a second algorithm in program form.

  12. Formation of Micro and Nano Structures Using VUV 157 nm Laser Radiation

    SciTech Connect

    Walton, C. D.; Cockcroft, S.

    2010-10-08

    We report on laser ablation experiments on micro and nano size composite structures. The surface of CR-39 and polycarbonate has been intentionally seeded with silicon carbide and silver nanowires and subsequently laser irradiated at a wavelength of 157 nm. We show scanning electron micrograph images of prismatic and conical structures produced by laser ablation and discuss a shape transformation from a prismatic to a conical structure.

  13. A new method to integrate ZnO nano-tetrapods on MEMS micro-hotplates for large scale gas sensor production

    NASA Astrophysics Data System (ADS)

    Marasso, S. L.; Tommasi, A.; Perrone, D.; Cocuzza, M.; Mosca, R.; Villani, M.; Zappettini, A.; Calestani, D.

    2016-09-01

    A new method, which is easily scalable to large scale production, has been developed to obtain gas sensor devices based on zinc oxide (ZnO) nanostructures with a ‘tetrapod’ shape. The method can be easily extended to other kinds of nanostructures and is based on the deposition of ZnO nanostructures through polymeric masks by centrifugation, directly onto properly designed MEMS micro-hotplates. The micromachined devices, after the mask is peeled off, are ready for electrical bonding and sensing test. Sensor response has been successfully measured for some gases and volatile organic compounds with different chemical properties (ethanol, methane, nitrogen dioxide, hydrogen sulfide).

  14. A new method to integrate ZnO nano-tetrapods on MEMS micro-hotplates for large scale gas sensor production.

    PubMed

    Marasso, S L; Tommasi, A; Perrone, D; Cocuzza, M; Mosca, R; Villani, M; Zappettini, A; Calestani, D

    2016-09-23

    A new method, which is easily scalable to large scale production, has been developed to obtain gas sensor devices based on zinc oxide (ZnO) nanostructures with a 'tetrapod' shape. The method can be easily extended to other kinds of nanostructures and is based on the deposition of ZnO nanostructures through polymeric masks by centrifugation, directly onto properly designed MEMS micro-hotplates. The micromachined devices, after the mask is peeled off, are ready for electrical bonding and sensing test. Sensor response has been successfully measured for some gases and volatile organic compounds with different chemical properties (ethanol, methane, nitrogen dioxide, hydrogen sulfide). PMID:27532770

  15. A new method to integrate ZnO nano-tetrapods on MEMS micro-hotplates for large scale gas sensor production.

    PubMed

    Marasso, S L; Tommasi, A; Perrone, D; Cocuzza, M; Mosca, R; Villani, M; Zappettini, A; Calestani, D

    2016-09-23

    A new method, which is easily scalable to large scale production, has been developed to obtain gas sensor devices based on zinc oxide (ZnO) nanostructures with a 'tetrapod' shape. The method can be easily extended to other kinds of nanostructures and is based on the deposition of ZnO nanostructures through polymeric masks by centrifugation, directly onto properly designed MEMS micro-hotplates. The micromachined devices, after the mask is peeled off, are ready for electrical bonding and sensing test. Sensor response has been successfully measured for some gases and volatile organic compounds with different chemical properties (ethanol, methane, nitrogen dioxide, hydrogen sulfide).

  16. Structural vibration control of micro/macro-manipulator using feedforward and feedback approaches

    SciTech Connect

    Lew, J.Y.; Cannon, D.W.; Magee, D.P.; Book, W.J.

    1995-09-01

    Pacific Northwest Laboratory (PDL) researchers investigated the combined use of two control approaches to minimize micro/macro-manipulator structural vibration: (1) modified input shaping and (2) inertial force active damping control. Modified input shaping (MIS) is used as a feedforward controller to modify reference input by canceling the vibratory motion. Inertial force active damping (IFAD) is applied as a feedback controller to increase the system damping and robustness to unexpected disturbances. Researchers implemented both control schemes in the PNL micro/macro flexible-link manipulator testbed collaborating with Georgia Institute of Technology. The experiments successfully demonstrated the effectiveness of two control approaches in reducing structural vibration. Based on the results of the experiments, the combined use of two controllers is recommended for a micro/macro manipulator to achieve the fastest response to commands while canceling disturbances from unexpected forces.

  17. Micro-wrinkling and delamination-induced buckling of stretchable electronic structures

    SciTech Connect

    Oyewole, O. K.; Yu, D.; Du, J.; Asare, J.; Fashina, A.; Oyewole, D. O.; Anye, V. C.; Zebaze Kana, M. G.; and others

    2015-06-21

    This paper presents the results of experimental and theoretical/computational micro-wrinkles and buckling on the surfaces of stretchable poly-dimethylsiloxane (PDMS) coated with nano-scale Gold (Au) layers. The wrinkles and buckles are formed by the unloading of pre-stretched PDMS/Au structure after the evaporation of nano-scale Au layers. They are then characterized using atomic force microscopy and scanning electron microscopy. The critical stresses required for wrinkling and buckling are analyzed using analytical models. The possible interfacial cracking that can occur along with film buckling is also studied using finite element simulations of the interfacial crack growth. The implications of the results are discussed for potential applications of micro-wrinkles and micro-buckles in stretchable electronic structures and biomedical devices.

  18. Micro-Structures of Hard Coatings Deposited on Titanium Alloys by Laser Alloying Technique

    NASA Astrophysics Data System (ADS)

    Li, Wei; Yu, Huijun; Chen, Chuanzhong; Wang, Diangang; Weng, Fei

    2013-02-01

    This work is based on micro-structural performance of the Ti-B4C-C laser alloying coatings on Ti-6Al-4V titanium alloy. The test results indicated that laser alloying of the Ti-B4C-C pre-placed powders on the Ti-6Al-4V alloy substrate can form the ceramics reinforced hard alloying coatings, which increased the micro-hardness and wear resistance of substrate. The test result also indicated that the TiB phase was produced in alloying coating, which corresponded to its (101) crystal plane. In addition, yttria has a refining effect on micro-structures of the laser alloying coating, and its refinement mechanism was analyzed. This research provided essential experimental and theoretical basis to promote the applications of the laser alloying technique in manufacturing and repairing of the aerospace parts.

  19. Micro-wrinkling and delamination-induced buckling of stretchable electronic structures

    NASA Astrophysics Data System (ADS)

    Oyewole, O. K.; Yu, D.; Du, J.; Asare, J.; Oyewole, D. O.; Anye, V. C.; Fashina, A.; Zebaze Kana, M. G.; Soboyejo, W. O.

    2015-06-01

    This paper presents the results of experimental and theoretical/computational micro-wrinkles and buckling on the surfaces of stretchable poly-dimethylsiloxane (PDMS) coated with nano-scale Gold (Au) layers. The wrinkles and buckles are formed by the unloading of pre-stretched PDMS/Au structure after the evaporation of nano-scale Au layers. They are then characterized using atomic force microscopy and scanning electron microscopy. The critical stresses required for wrinkling and buckling are analyzed using analytical models. The possible interfacial cracking that can occur along with film buckling is also studied using finite element simulations of the interfacial crack growth. The implications of the results are discussed for potential applications of micro-wrinkles and micro-buckles in stretchable electronic structures and biomedical devices.

  20. Real-Time Visualization of Platelet Interaction With Micro Structured Surfaces.

    PubMed

    Gester, Kathrin; Birtel, Stephan; Clauser, Johanna; Steinseifer, Ulrich; Sonntag, Simon Johannes

    2016-02-01

    Improving the hemocompatibility of artificial implants by micro structuring their surfaces has shown promising results, but the mechanisms which lead to this improvement are not yet understood. Therefore, we built a test setup for real-time visualization of platelet interaction with a plain and two micro structured surfaces. The micro structures, defined by the distance of the plain surface area between the structures, were chosen to be 3 and 30 μm, representing a positive and a negative effect on the hemocompatibility. The main part of the test setup was a flow chamber containing films of low density polyethylene (LDPE) with the differently structured surfaces. For different wall shear stresses, no considerable differences were observed in the platelet-surface interaction for all surface types. Whereas, major differences in flow behavior were observed when comparing the surfaces to each other. The platelets "rolled" along the smooth surface, being in constant contact with the surface material. Although the platelets "rolled" over the surface with small structures as well, they were only in contact with the tips of the structure and therefore had less surface contact with the foreign material. The increased distance and height of the structures of the last surface led to a trapping of platelets between the structures. This resulted in a longer contact time with the foreign material as well as a larger contact area, which both increase the risk of platelet activation, adhesion, and finally clotting. Our results showed the mechanisms which lead to these effects and thus revealed why micro structuring of surfaces impacts the hemocompatibility. Furthermore, we established a test setup which can be used for future investigations on the platelet-structure interactions.