WorldWideScience

Sample records for chemical sensors

  1. Chemical sensors

    Science.gov (United States)

    Lowell, J.R. Jr.; Edlund, D.J.; Friesen, D.T.; Rayfield, G.W.

    1991-07-02

    Sensors responsive to small changes in the concentration of chemical species are disclosed. The sensors comprise a mechanochemically responsive polymeric film capable of expansion or contraction in response to a change in its chemical environment. They are operatively coupled to a transducer capable of directly converting the expansion or contraction to a measurable electrical response. 9 figures.

  2. Capacitive chemical sensor

    Science.gov (United States)

    Manginell, Ronald P; Moorman, Matthew W; Wheeler, David R

    2014-05-27

    A microfabricated capacitive chemical sensor can be used as an autonomous chemical sensor or as an analyte-sensitive chemical preconcentrator in a larger microanalytical system. The capacitive chemical sensor detects changes in sensing film dielectric properties, such as the dielectric constant, conductivity, or dimensionality. These changes result from the interaction of a target analyte with the sensing film. This capability provides a low-power, self-heating chemical sensor suitable for remote and unattended sensing applications. The capacitive chemical sensor also enables a smart, analyte-sensitive chemical preconcentrator. After sorption of the sample by the sensing film, the film can be rapidly heated to release the sample for further analysis. Therefore, the capacitive chemical sensor can optimize the sample collection time prior to release to enable the rapid and accurate analysis of analytes by a microanalytical system.

  3. Wearable Optical Chemical Sensors

    Science.gov (United States)

    Lobnik, Aleksandra

    Wearable sensors can be used to provide valuable information about the wearer's health and/or monitor the wearer's surroundings, identify safety concerns and detect threats, during the wearer's daily routine within his or her natural environment. The "sensor on a textile", an integrated sensor capable of analyzing data, would enable early many forms of detection. Moreover, a sensor connected with a smart delivery system could simultaneously provide comfort and monitoring (for safety and/or health), non-invasive measurements, no laboratory sampling, continuous monitoring during the daily activity of the person, and possible multi-parameter analysis and monitoring. However, in order for the technology to be accessible, it must remain innocuous and impose a minimal intrusion on the daily activities of the wearer. Therefore, such wearable technologies should be soft, flexible, and washable in order to meet the expectations of normal clothing. Optical chemical sensors (OCSs) could be used as wearable technology since they can be embedded into textile structures by using conventional dyeing, printing processes and coatings, while fiber-optic chemical sensors (FOCSs) as well as nanofiber sensors (NFSs) can be incorporated by weaving, knitting or laminating. The interest in small, robust and sensitive sensors that can be embedded into textile structures is increasing and the research activity on this topic is an important issue.

  4. Fiber Bragg distributed chemical sensor

    NARCIS (Netherlands)

    Boersma, A.; Cheng, L.K.; Jansen, T.H.

    2010-01-01

    A distributed chemical sensor is developed by coating multiple Bragg gratings in a fibre with chemical selective responsive coatings. The optical response of the coated grating is optimised and the recoat process is very reproducible.

  5. Imprinted photonic crystal chemical sensors

    NARCIS (Netherlands)

    Boersma, A.; Burghoorn, M.M.A.; Saalmink, M.

    2011-01-01

    In this paper we present the use of Photonic Crystals as chemical sensors. These 2D nanostructured sensors were prepared by nano-imprint lithography during which a nanostructure is transferred from a nickel template into a responsive polymer, that is be specifically tuned to interact with the chemic

  6. Errors in Chemical Sensor Measurements

    Directory of Open Access Journals (Sweden)

    Artur Dybko

    2001-06-01

    Full Text Available Various types of errors during the measurements of ion-selective electrodes, ionsensitive field effect transistors, and fibre optic chemical sensors are described. The errors were divided according to their nature and place of origin into chemical, instrumental and non-chemical. The influence of interfering ions, leakage of the membrane components, liquid junction potential as well as sensor wiring, ambient light and temperature is presented.

  7. Fiber Bragg distributed chemical sensor

    NARCIS (Netherlands)

    Boersma, A.; Saalmink, M.; Lucassen, T.; Wiegersma, S.; Jansen, T.H.; Jansen, R.; Cheng, L.K.

    2011-01-01

    A distributed chemical sensor is developed by coating multiple Bragg gratings in a single glass fiber with chemical responsive coatings. The composition of the coating is tuned to the target chemicals to be measured and the optical response of the coated grating is optimized by changing the coating

  8. Graphene Chemical Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The sensor uses graphene based devices to sense the surface potential of a graphene channel exposed to an analyte. When analyte molecules adsorb onto the...

  9. Fiber Optic Chemical Sensors

    Science.gov (United States)

    1993-10-01

    Studies Press Ltd, Book Chapter, AIS, 1-25, 1983. Saarl, Linda A. and Seltz, Rudolf W., "Immobilized Morin as Fluorescence Sensor for Determination...34Thin Films," Photonics Spectra, AVO, AIS, 113-118, 1988. Hanst, Philip L. and Stephens, Edgar R., "Infrared Analysis of Engine Exhausts: Methyl...79-84, 1988. Watson, Jr., Edgar , "On-line Analysis of Trace Contaminants 145 36 in Process Streams," Amarican Laboratory, AVO, AIS, 97-101, 1988

  10. Integrated opto-chemical sensors

    NARCIS (Netherlands)

    Lambeck, Paul V.

    1992-01-01

    Integrated opto-chemical sensors have promising prospects, for example by having the potential to be realized as very sensitive small monolithic smart multisensor systems with a digital signal output. Here the main accent will be laid on the optical principles underlying chemo-optical waveguiding se

  11. Advanced millimeter wave chemical sensor.

    Energy Technology Data Exchange (ETDEWEB)

    Gopalsami, N.

    1999-03-24

    This paper discusses the development of an advanced millimeter-wave (mm-wave) chemical sensor and its applications for environmental monitoring and arms control treaty verification. The purpose of this work is to investigate the use of fingerprint-type molecular rotational signatures in the mm-wave spectrum to sense airborne chemicals. The mm-wave spectrum to sense airborne chemicals. The mm-wave sensor, operating in the frequency range of 220-300 GHz, can work under all weather conditions and in smoky and dusty environments. The basic configuration of the mm-wave sensor is a monostatic swept-frequency radar consisting of a mm-wave sweeper, a hot-electron-bolometer or Schottky barrier detector, and a trihedral reflector. The chemical plume to be detected is situated between the transmitter/detector and the reflector. Millimeter-wave absorption spectra of chemicals in the plume are determined by measuring the swept-frequency radar return signals with and without the plume in the beam path. The problem of pressure broadening, which hampered open-path spectroscopy in the past, has been mitigated in this work by designing a fast sweeping source over a broad frequency range. The heart of the system is a Russian backward-wave oscillator (BWO) tube that can be tuned over 220-350 GHz. Using the Russian BWO tube, a mm-wave radar system was built and field-tested at the DOE Nevada Test Site at a standoff distance of 60 m. The mm-wave system detected chemical plumes very well; the detection sensitivity for polar molecules like methyl chloride was down to a concentration of 12 ppm.

  12. Ubiquitous Sensor Network for Chemical Sensors

    Institute of Scientific and Technical Information of China (English)

    Wan-Young Chung; Risto Myllylae

    2006-01-01

    Wireless sensor networks have been identified as one of the most important technologies for the 21st century. Recent advances in micro sensor fabrication technology and wireless communication technology enable the practical deployment of large-scale, low-power, inexpensive sensor networks. Such an approach offers an advantage over traditional sensing methods in many ways: large-scale, dense deployment not only extends spatial coverage and achieves higher resolution, but also increases the system's fault-tolerance and robustness. Moreover, the ad-hoc nature of wireless sensor networks makes them even more attractive for military and other risk-associated applications, such as environmental observation and habitat monitoring.

  13. Nanotube-Based Chemical and Biomolecular Sensors

    Institute of Scientific and Technical Information of China (English)

    J.Koh; B.Kim; S.Hong; H.Lim; H.C.Choi

    2008-01-01

    We present a brief review about recent results regarding carbon nanotube (CNT)-based chemical and biomolecular sensors. For the fabrication of CNT-based sensors, devices containing CNT channels between two metal electrodes are first fabricated usually via chemical vapor deposition (CVD) process or "surface programmed assembly" method. Then, the CNT surfaces are often functionalized to enhance the selectivity of the sensors. Using this process, highly-sensitive CNT-based sensors can be fabricated for the selective detection of various chemical and biological molecules such as hydrogen, ammonia, carbon monoxide, chlorine gas, DNA, glucose, alcohol, and proteins.

  14. Passive in-situ chemical sensor

    Science.gov (United States)

    Morrell, Jonathan S.; Ripley, Edward B.

    2012-02-14

    A chemical sensor for assessing a chemical of interest. In typical embodiments the chemical sensor includes a first thermocouple and second thermocouple. A reactive component is typically disposed proximal to the second thermal couple, and is selected to react with the chemical of interest and generate a temperature variation that may be detected by a comparison of a temperature sensed by the second thermocouple compared with a concurrent temperature detected by the first thermocouple. Further disclosed is a method for assessing a chemical of interest and a method for identifying a reaction temperature for a chemical of interest in a system.

  15. Polymers for Chemical Sensors Using Hydrosilylation Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Grate, Jay W.; Kaganove, Steven N.; Nelson, David A.

    2001-06-28

    Sorbent and functionalized polymers play a key role in a diverse set of fields, including chemical sensors, separation membranes, solid phase extraction techniques, and chromatography. Sorbent polymers are critical to a number of sensor array or "electronic nose" systems. The responses of the sensors in the array give rise to patterns that can be used to distinguish one compound from another, provided that a sufficiently diverse set of sensing materials is present in the array. Figure 1 illustrates the concept of several sensors, each with a different sensor coating, giving rise to variable responses to an analyte that appear as a pattern in bar graph format. Using hydrosilylation as the bond-forming reaction, we have developed a versatile and efficient approach to developing sorbent polymers with diverse interactive properties for sensor applications. Both the chemical and physical properties of these polymers are predictable and tunable by design.

  16. Microfabricated Chemical Gas Sensors and Sensor Arrays for Aerospace Applications

    Science.gov (United States)

    Hunter, Gary W.

    2005-01-01

    Aerospace applications require the development of chemical sensors with capabilities beyond those of commercially available sensors. In particular, factors such as minimal sensor size, weight, and power consumption are particularly important. Development areas which have potential aerospace applications include launch vehicle leak detection, engine health monitoring, and fire detection. Sensor development for these applications is based on progress in three types of technology: 1) Micromachining and microfabrication (Microsystem) technology to fabricate miniaturized sensors; 2) The use of nanocrystalline materials to develop sensors with improved stability combined with higher sensitivity; 3) The development of high temperature semiconductors, especially silicon carbide. This presentation discusses the needs of space applications as well as the point-contact sensor technology and sensor arrays being developed to address these needs. Sensors to measure hydrogen, hydrocarbons, nitrogen oxides (NO,), carbon monoxide, oxygen, and carbon dioxide are being developed as well as arrays for leak, fire, and emissions detection. Demonstrations of the technology will also be discussed. It is concluded that microfabricated sensor technology has significant potential for use in a range of aerospace applications.

  17. Coordinated sensor cueing for chemical plume detection

    Science.gov (United States)

    Abraham, Nathan J.; Jensenius, Andrea M.; Watkins, Adam S.; Hawthorne, R. Chad; Stepnitz, Brian J.

    2011-05-01

    This paper describes an organic data fusion and sensor cueing approach for Chemical, Biological, Radiological, and Nuclear (CBRN) sensors. The Joint Warning and Reporting Network (JWARN) uses a hardware component referred to as the JWARN Component Interface Device (JCID). The Edgewood Chemical and Biological Center has developed a small footprint and open architecture solution for the JCID capability called JCID-on-a-Chip (JoaC). The JoaC program aims to reduce the cost and complexity of the JCID by shrinking the necessary functionality down to a small single board computer. This effort focused on development of a fusion and cueing algorithm organic to the JoaC hardware. By embedding this capability in the JoaC, sensors have the ability to receive and process cues from other sensors without the use of a complex and costly centralized infrastructure. Additionally, the JoaC software is hardware agnostic, as evidenced by its drop-in inclusion in two different system-on-a-chip platforms including Windows CE and LINUX environments. In this effort, a partnership between JPM-CA, JHU/APL, and the Edgewood Chemical and Biological Center (ECBC), the authors implemented and demonstrated a new algorithm for cooperative detection and localization of a chemical agent plume. This experiment used a pair of mobile Joint Services Lightweight Standoff Chemical Agent Detector (JSLSCAD) units which were controlled by fusion and cueing algorithms hosted on a JoaC. The algorithms embedded in the JoaC enabled the two sensor systems to perform cross cueing and cooperatively form a higher fidelity estimate of chemical releases by combining sensor readings. Additionally, each JSLSCAD had the ability to focus its search on smaller regions than those required by a single sensor system by using the cross cue information from the other sensor.

  18. Graphene chemical sensors for heliophysics applications

    Science.gov (United States)

    Sultana, Mahmooda; Herrero, Fred; Khazanov, George

    2013-10-01

    Graphene is a single layer of carbon atoms that offer a unique set of advantages as a chemical sensor due to a number of its inherent properties. Graphene has been explored as a gas sensor for a variety of gases, and molecular sensitivity has been demonstrated by measuring the change in electrical properties due to the adsorption of target species (Schedin, F.; Geim, A.K.; Morozov, S.V.; Hill, E.W.; Blake, P.; Katsnelson, M.I.; Novoselov, K.S. Nat. Mater 2007, 6, 652-655. doi:10.1038/nmat1967). In this paper, we discuss the development of an array of chemical sensors based on graphene and its relevance to plasma physics due to its sensitivity to radical species such as O+, H+ and the corresponding neutrals. We briefly discuss the great impact such sensors will have on a number of heliophysics applications such as ground-based manifestations of space weather.

  19. Graphene Chemical Sensor for Heliophysics Applications

    Science.gov (United States)

    Sultana, Mahmooda; Herrero, Fred; Khazanov, George

    2013-01-01

    Graphene is a single layer of carbon atoms that offer a unique set of advantages as a chemical sensor due to a number of its inherent properties. Graphene has been explored as a gas sensor for a variety of gases, and molecular sensitivity has been demonstrated by measuring the change in electrical properties due to the adsorption of target species. In this paper, we discuss the development of an array of chemical sensors based on graphene and its relevance to plasma physics due to its sensitivity to radical species such as oxonium, hydron and the corresponding neutrals. We briefly discuss the great impact such sensors will have on a number of heliophysics applications such as ground-based manifestations of space weather.

  20. Micromachined chemical sensor with integrated microelectronics

    Science.gov (United States)

    Smith, J.; Sniegowski, J.; Koehler, D.; Ricco, T.; Martin, S.; McWhorter, P.

    With today's continued emphasis on environmental safety and health issues, a resurgence of interest has developed in the area of chemical sensors. These sensors would typically be used to monitor contamination hazards such as underground storage tanks or to assess previous contamination at waste disposal sites. Human exposure to chemical hazards can also be monitored. Additionally, these sensors can be used as part of a manufacturing process control loop. One type of sensor suitable for gas phase monitoring of chemicals is the quartz resonator or quartz crystal microbalance (QCM) sensor. In this type of sensor, a thickness shear mode (TSM) quartz resonator is coated with a film that interacts with the chemical species of interest. Changes in the mass and elasticity of this film are reflected as changes in the resonant properties of the device. Therefore, the presence of the species of interest can be detected by monitoring the frequency of an oscillator based on the resonance of the quartz. These QCM sensors compete with surface acoustic wave (SAW) devices as a means for monitoring gas phase species. SAW devices are typically more sensitive to small amounts of a species, but the instrumentation associated with a SAW device is an order of magnitude more expensive than the instrumentation associated with a TSM wave resonator since the SAW devices operate in the 100's of MHz frequency regime while quartz resonators operate in the 5-25 MHz regime. We are working to improve the sensitivity of the QCM sensor by increasing the frequency of the device to 25 MHz (compared to the typical 5 MHz crystal) and by increasing the frequency stability of the system to an ultimate goal of 0.1 Hz. The 25 MHz QCM has already been achieved, and once the stability goal is achieved, the QCM will have the same sensitivity as a SAW device.

  1. Uncoated microcantilevers as chemical sensors

    Energy Technology Data Exchange (ETDEWEB)

    Thundat, Thomas G. (Knoxville, TN)

    2001-01-01

    A method and device are provided for chemical sensing using cantilevers that do not use chemically deposited, chemically specific layers. This novel device utilizes the adsorption-induced variation in the surfaces states on a cantilever. The methodology involves exciting charge carriers into or out of the surface states with photons having increasing discrete levels of energy. The excitation energy is provided as discrete levels of photon energy by scanning the wavelength of an exciting source that is illuminating the cantilever surface. When the charge carriers are excited into or out of the surface states, the cantilever bending changes due to changes in surface stress. The amount of cantilever bending with respect to an identical cantilever as a function of excitation energy is used to determine the energy levels associated with adsorbates.

  2. Wide-Area Chemical Sensor

    Science.gov (United States)

    2014-11-01

    2014www.ll.mit.edu The detection and localization of gas releases such as methane from leaking natural gas pipelines or nitrogen oxides from failing electrical...reference gas cells, such as methane buffered by nitro- gen, and a low-concentration gas cell that contains the target species to calibrate the...self-referencing technique employed by WACS is particularly suited to detecting chemical agents composed of primarily small molecules— methane , various

  3. Integrated optical sensors for the chemical domain

    NARCIS (Netherlands)

    Lambeck, Paul V.

    2006-01-01

    During the last decade there has been a rapidly growing interest in integrated optical (IO) sensors, expecially because many of them principally allow for sensitive, real time, label-free-on-site measurements of the concentration of (bio-)chemical species. This review aims at giving an overview of t

  4. Electrostatic thin film chemical and biological sensor

    Science.gov (United States)

    Prelas, Mark A.; Ghosh, Tushar K.; Tompson, Jr., Robert V.; Viswanath, Dabir; Loyalka, Sudarshan K.

    2010-01-19

    A chemical and biological agent sensor includes an electrostatic thin film supported by a substrate. The film includes an electrostatic charged surface to attract predetermined biological and chemical agents of interest. A charge collector associated with said electrostatic thin film collects charge associated with surface defects in the electrostatic film induced by the predetermined biological and chemical agents of interest. A preferred sensing system includes a charge based deep level transient spectroscopy system to read out charges from the film and match responses to data sets regarding the agents of interest. A method for sensing biological and chemical agents includes providing a thin sensing film having a predetermined electrostatic charge. The film is exposed to an environment suspected of containing the biological and chemical agents. Quantum surface effects on the film are measured. Biological and/or chemical agents can be detected, identified and quantified based on the measured quantum surface effects.

  5. Conducting polymers in electronic chemical sensors.

    Science.gov (United States)

    Janata, Jiri; Josowicz, Mira

    2003-01-01

    Conducting organic polymers have found two main kinds of application in electronics so far: as materials for construction of various devices and as selective layers in chemical sensors. In either case, interaction with ambient gases is critical. It may compromise the performance of a device based on conducting polymers, whereas it is beneficial in a sensor. Conductivity has been the primary property of interest. Work function--related to conductivity, but in principle a different property--has received only scant attention. Our aim here is to discuss the usability of conducting polymers in both types of electronic applications in light of these two parameters.

  6. Modeling Microscopic Chemical Sensors in Capillaries

    CERN Document Server

    Hogg, Tad

    2008-01-01

    Nanotechnology-based microscopic robots could provide accurate in vivo measurement of chemicals in the bloodstream for detailed biological research and as an aid to medical treatment. Quantitative performance estimates of such devices require models of how chemicals in the blood diffuse to the devices. This paper models microscopic robots and red blood cells (erythrocytes) in capillaries using realistic distorted cell shapes. The models evaluate two sensing scenarios: robots moving with the cells past a chemical source on the vessel wall, and robots attached to the wall for longer-term chemical monitoring. Using axial symmetric geometry with realistic flow speeds and diffusion coefficients, we compare detection performance with a simpler model that does not include the cells. The average chemical absorption is quantitatively similar in both models, indicating the simpler model is an adequate design guide to sensor performance in capillaries. However, determining the variation in forces and absorption as cells...

  7. Biomimetic chemical sensors using bioengineered olfactory and taste cells

    OpenAIRE

    Du, Liping; Zou, Ling; Zhao, Luhang; Wang, Ping; Wu, Chunsheng

    2014-01-01

    Biological olfactory and taste systems are natural chemical sensing systems with unique performances for the detection of environmental chemical signals. With the advances in olfactory and taste transduction mechanisms, biomimetic chemical sensors have achieved significant progress due to their promising prospects and potential applications. Biomimetic chemical sensors exploit the unique capability of biological functional components for chemical sensing, which are often sourced from sensing ...

  8. Waveguide-based optical chemical sensor

    Science.gov (United States)

    Grace, Karen M.; Swanson, Basil I.; Honkanen, Seppo

    2007-03-13

    The invention provides an apparatus and method for highly selective and sensitive chemical sensing. Two modes of laser light are transmitted through a waveguide, refracted by a thin film host reagent coating on the waveguide, and analyzed in a phase sensitive detector for changes in effective refractive index. Sensor specificity is based on the particular species selective thin films of host reagents which are attached to the surface of the planar optical waveguide. The thin film of host reagents refracts laser light at different refractive indices according to what species are forming inclusion complexes with the host reagents.

  9. Carbon-Nanotube-Based Chemical Gas Sensor

    Science.gov (United States)

    Kaul, Arunpama B.

    2010-01-01

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

  10. Nanoscale chemical sensor based on organic thin-film transistors

    Science.gov (United States)

    Wang, Liang; Fine, Daniel; Dodabalapur, Ananth

    2004-12-01

    Nanoscale organic thin-film transistors were fabricated to investigate their chemical sensing properties. The use of a four-terminal geometry ensures that the sensor active area is truly nanoscale, and eliminates undesirable spreading currents. The sensor response was markedly different in nanoscale sensors compared to large-area sensors for the same analyte-semiconductor combination. The chemical sensing mechanisms in both microscale and nanoscale transistors are briefly discussed.

  11. Development of GaN-based micro chemical sensor nodes

    Science.gov (United States)

    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.

  12. Progress of Mimetic Enzymes and Their Applications in Chemical Sensors.

    Science.gov (United States)

    Yang, Bin; Li, Jianping; Deng, Huan; Zhang, Lianming

    2016-11-01

    The need to develop innovative and reformative approaches to synthesize chemical sensors has increased in recent years because of demands for selectivity, stability, and reproducibility. Mimetic enzymes provide an efficient and convenient method for chemical sensors. This review summarizes the application of mimetic enzymes in chemical sensors. Mimetic enzymes can be classified into five categories: hydrolases, oxidoreductases, transferases, isomerases, and induced enzymes. Potential and recent applications of mimetic enzymes in chemical sensors are reviewed in detail, and the outlook of profound development has been illustrated.

  13. Design Of Piezoelectric Microcantilever Chemical Sensors In COMSOL Multiphysics Area

    OpenAIRE

    Maziar Norouzi; Alireza Kashaninia

    2009-01-01

    This paper offers an analytical modeling ofthin-filmed, multi-layer piezoelectric microcantileversthat are used as MEMS sensors. These sensors arechemical kind and use piezoelectric microcantilever.These types of microcantilevers are covered withvariety of unique probe coating. The sensor has highsensitivity with external voltage measured in mV anduses PSD1 system to indentify chemical ingredients ofmaterials. The identification of the chemical ingredientof materials is based on change in ang...

  14. Evaluating Zeolite-Modified Sensors: towards a faster set of chemical sensors

    Science.gov (United States)

    Berna, A. Z.; Vergara, A.; Trincavelli, M.; Huerta, R.; Afonja, A.; Parkin, I. P.; Binions, R.; Trowell, S.

    2011-09-01

    The responses of zeolite-modified sensors, prepared by screen printing layers of chromium titanium oxide (CTO), were compared to unmodified tin oxide sensors using amplitude and transient responses. For transient responses we used a family of features, derived from the exponential moving average (EMA), to characterize chemo-resistive responses. All sensors were tested simultaneously against 20 individual volatile compounds from four chemical groups. The responses of the two types of sensors showed some independence. The zeolite-modified CTO sensors discriminated compounds better using either amplitude response or EMA features and CTO-modified sensors also responded three times faster.

  15. Nanotechnologv Enabled Biological and Chemical Sensors

    Science.gov (United States)

    Koehne, Jessica; Meyyappan, M.

    2011-01-01

    Nanotechnology is an enabling technology that will impact almost all economic sectors: one of the most important and with great potential is the health/medical sector. - Nanomaterials for drug delivery - Early warning sensors - Implantable devices - Artificial parts with improved characteristics Carbon nanotubes and nanofibers show promise for use in sensor development, electrodes and other biomedical applications.

  16. Non-specific sensor arrays for chemical detection

    Science.gov (United States)

    Johnson, Kevin; Minor, Christian

    2015-05-01

    Non-specific chemical sensor arrays have been the subject of considerable research efforts over the past thirty years with the idea that, by analogy to vertebrate olfaction, they are potentially capable of rendering complex chemical assessments with relatively modest logistical footprints. However, the actual implementation of such devices in challenging "real world" scenarios has arguably continued to fall short of these expectations. This work examines the inherent limitations of such devices for complex chemical sensing scenarios, placing them on a continuum between simple univariate sensors and complex multivariate analytical instrumentation and analyzing their utility in general-purpose chemical detection and accurate chemical sensing in the presence of unknown "unknowns." Results with simulated and acquired data sets are presented with discussion of the implications in development of chemical sensor arrays suitable for complex scenarios.

  17. Zirconia-based solid state chemical gas sensors

    CERN Document Server

    Zhuiykov, S

    2000-01-01

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

  18. Autonomous chemical and biological miniature wireless-sensor

    Science.gov (United States)

    Goldberg, Bar-Giora

    2005-05-01

    The presentation discusses a new concept and a paradigm shift in biological, chemical and explosive sensor system design and deployment. From large, heavy, centralized and expensive systems to distributed wireless sensor networks utilizing miniature platforms (nodes) that are lightweight, low cost and wirelessly connected. These new systems are possible due to the emergence and convergence of new innovative radio, imaging, networking and sensor technologies. Miniature integrated radio-sensor networks, is a technology whose time has come. These network systems are based on large numbers of distributed low cost and short-range wireless platforms that sense and process their environment and communicate data thru a network to a command center. The recent emergence of chemical and explosive sensor technology based on silicon nanostructures, coupled with the fast evolution of low-cost CMOS imagers, low power DSP engines and integrated radio chips, has created an opportunity to realize the vision of autonomous wireless networks. These threat detection networks will perform sophisticated analysis at the sensor node and convey alarm information up the command chain. Sensor networks of this type are expected to revolutionize the ability to detect and locate biological, chemical, or explosive threats. The ability to distribute large numbers of low-cost sensors over large areas enables these devices to be close to the targeted threats and therefore improve detection efficiencies and enable rapid counter responses. These sensor networks will be used for homeland security, shipping container monitoring, and other applications such as laboratory medical analysis, drug discovery, automotive, environmental and/or in-vivo monitoring. Avaak"s system concept is to image a chromatic biological, chemical and/or explosive sensor utilizing a digital imager, analyze the images and distribute alarm or image data wirelessly through the network. All the imaging, processing and communications

  19. Biomimetic chemical sensors using bioengineered olfactory and taste cells

    Science.gov (United States)

    Du, Liping; Zou, Ling; Zhao, Luhang; Wang, Ping; Wu, Chunsheng

    2014-01-01

    Biological olfactory and taste systems are natural chemical sensing systems with unique performances for the detection of environmental chemical signals. With the advances in olfactory and taste transduction mechanisms, biomimetic chemical sensors have achieved significant progress due to their promising prospects and potential applications. Biomimetic chemical sensors exploit the unique capability of biological functional components for chemical sensing, which are often sourced from sensing units of biological olfactory or taste systems at the tissue level, cellular level, or molecular level. Specifically, at the cellular level, there are mainly two categories of cells have been employed for the development of biomimetic chemical sensors, which are natural cells and bioengineered cells, respectively. Natural cells are directly isolated from biological olfactory and taste systems, which are convenient to achieve. However, natural cells often suffer from the undefined sensing properties and limited amount of identical cells. On the other hand, bioengineered cells have shown decisive advantages to be applied in the development of biomimetic chemical sensors due to the powerful biotechnology for the reconstruction of the cell sensing properties. Here, we briefly summarized the most recent advances of biomimetic chemical sensors using bioengineered olfactory and taste cells. The development challenges and future trends are discussed as well. PMID:25482234

  20. Development of Microfabricated Chemical Gas Sensors and Sensor Arrays for Aerospace Applications

    Science.gov (United States)

    Hunter, G. W.; Neudeck, P. G.; Fralick, G.; Thomas, V.; Liu, C. C.; Wu, W. H.; Ward, B.; Makel, D.

    2002-01-01

    Aerospace applications require the development of chemical sensors with capabilities beyond those of commercially available sensors. In particular, factors such as minimal sensor size, weight, and power consumption are particularly important. Development areas which have potential aerospace applications include launch vehicle leak detection, engine health monitoring, fire detection, and environmental monitoring. Sensor development for these applications is based on progress in three types of technology: 1) Micromachining and microfabrication (Microsystem) technology to fabricate miniaturized sensors. 2) The use of nanocrystalline materials to develop sensors with improved stability combined with higher sensitivity. 3) The development of high temperature semiconductors, especially silicon carbide. However, due to issues of selectivity and cross-sensitivity, individual sensors are limited in the amount of information that they can provide in environments that contain multiple chemical species. Thus, sensor arrays are being developed to address detection needs in such multi-species environments. This paper discusses the needs of space applications as well as the point-contact sensor technology and sensor arrays being developed to address these needs. Sensors to measure hydrogen, hydrocarbons, hydrazine, nitrogen oxides (NO,), carbon monoxide, oxygen, and carbon dioxide are being developed as well as arrays for leak, fire, and emissions detection. Demonstrations of the technology will also be discussed. It is concluded that microfabricated sensor technology has significant potential for use in a range of aerospace applications.

  1. Piezoresistive Chemical Sensors Based on Functionalized Hydrogels

    Directory of Open Access Journals (Sweden)

    Margarita Guenther

    2014-06-01

    Full Text Available Thin films of analyte-specific hydrogels were combined with microfabricated piezoresistive pressure transducers to obtain chemomechanical sensors that can serve as selective biochemical sensors for a continuous monitoring of metabolites. The gel swelling pressure has been monitored in simulated physiological solutions by means of the output signal of piezoresistive sensors. The interference by fructose, human serum albumin, pH, and ionic concentration on glucose sensing was studied. With the help of a database containing the calibration curves of the hydrogel-based sensors at different values of pH and ionic strength, the corrected values of pH and glucose concentration were determined using a novel calibration algorithm.

  2. Bragg grating chemical sensor with hydrogel as sensitive element

    Institute of Scientific and Technical Information of China (English)

    Xiaomei Liu(刘小梅); Shilie Zheng(郑史烈); Xianmin Zhang(章献民); Jun Cong(丛军); Kangsheng Chen(陈抗生); Jian Xu(徐坚)

    2004-01-01

    A novel fiber Bragg grating (FBG) based chemical sensor using hydrogel, a swellable polymer, as sensitive element is demonstrated. The sensing mechanism relies on the shift of Bragg wavelength due to the stress resulted from volume change of sensitive swellable hydrogel responding to the change of external environment. A polyacrylamide hydrogel fiber grating chemical sensor is made, and the experiments on its sensitivity to the salinity are performed. The sensitivity is low due to the less stress from the shrinking or swelling of hydrogels. Reducing the cross diameter of the grating through etching with hydrofluoric acid can greatly improve the sensitivity of the sensor.

  3. Utilization of biosensors and chemical sensors for space applications

    Science.gov (United States)

    Bonting, S. L.

    1992-01-01

    There will be a need for a wide array of chemical sensors for biomedical experimentation and for the monitoring of water and air recycling processes on Space Station Freedom. The infrequent logistics flights of the Space Shuttle will necessitate onboard analysis. The advantages of biosensors and chemical sensors over conventional analysis onboard spacecraft are manifold. They require less crew time, space, and power. Sample treatment is not needed. Real time or near-real time monitoring is possible, in some cases on a continuous basis. Sensor signals in digitized form can be transmitted to the ground. Types and requirements for chemical sensors to be used in biomedical experimentation and monitoring of water recycling during long-term space missions are discussed.

  4. Chemical Sensors Based on Piezoresistive Cantilever Array

    Institute of Scientific and Technical Information of China (English)

    于晓梅; 张大成; 王丛舜; 杜先锋; 王小宝; 阮勇

    2003-01-01

    U-shaped and rectangle piezoresistive cantilever arrays have been designed with the analysing results of stress,noise and sensitivity of the cantilevers. Based on silicon micromachining technology, the piezoresistive cantilevers were fabricated by using polysilicon as the piezoresistive materials. With the measurement results of noise and sensitivity, the Hooge factor is calculated to be 3 × 10-3, the gauge factor is 27, and the minimum detectable deflection of piezoresistive cantilevers are calculated to be 1.0nm for rectangle cantilever and 0.5 nm for the Ushaped cantilever at a 6 V bias voltage and a 1000 Hz measurement bandwidth. Using polymer-coated cantilevers as individual sensors, their responses to water vapour and ammonia were tested by measuring their output voltage signals. The measured results show that the sensor sensitivity to ammonia can reach a few ppm and the sensor responses are quick.

  5. Flexible optical chemical sensor platform for BTX

    OpenAIRE

    Arias Espinoza, Juan Diego; Sazhnikov, Viacheslav; Sabik, Sami; Ionov, Dmitriy; Smits, Edsger; Kalathimekkad, Sandeep; Van Steenberge, Geert; Alfimov, Michail; Posniak, Malgorzata; Schoo, Herman

    2012-01-01

    An in-plane flexible sensor platform for BTX detection was developed using low-cost patterning techniques and foil-based optical components. The platform was produced by a combination of laser patterning, inkjet printing and capillary filling. Key optical components such as lightguides, opticalcladding layers and metallic interconnections were realized on low cost substrates such as paper and PET. The sensing mechanism is based on the change in fluorescence spectra of a reporter dye, supporte...

  6. Solution-gated graphene transistors for chemical and biological sensors.

    Science.gov (United States)

    Yan, Feng; Zhang, Meng; Li, Jinhua

    2014-03-01

    Graphene has attracted much attention in biomedical applications for its fascinating properties. Because of the well-known 2D structure, every atom of graphene is exposed to the environment, so the electronic properties of graphene are very sensitive to charged analytes (ions, DNA, cells, etc.) or an electric field around it, which renders graphene an ideal material for high-performance sensors. Solution-gated graphene transistors (SGGTs) can operate in electrolytes and are thus excellent candidates for chemical and biological sensors, which have been extensively studied in the recent 5 years. Here, the device physics, the sensing mechanisms, and the performance of the recently developed SGGT-based chemical and biological sensors, including pH, ion, cell, bacterial, DNA, protein, glucose sensors, etc., are introduced. Their advantages and shortcomings, in comparison with some conventional techniques, are discussed. Conclusions and challenges for the future development of the field are addressed in the end.

  7. Fiber-Optic Chemical Sensors and Fiber-Optic Bio-Sensors

    Directory of Open Access Journals (Sweden)

    Marie Pospíšilová

    2015-09-01

    Full Text Available This review summarizes principles and current stage of development of fiber-optic chemical sensors (FOCS and biosensors (FOBS. Fiber optic sensor (FOS systems use the ability of optical fibers (OF to guide the light in the spectral range from ultraviolet (UV (180 nm up to middle infrared (IR (10 μm and modulation of guided light by the parameters of the surrounding environment of the OF core. The introduction of OF in the sensor systems has brought advantages such as measurement in flammable and explosive environments, immunity to electrical noises, miniaturization, geometrical flexibility, measurement of small sample volumes, remote sensing in inaccessible sites or harsh environments and multi-sensing. The review comprises briefly the theory of OF elaborated for sensors, techniques of fabrications and analytical results reached with fiber-optic chemical and biological sensors.

  8. Molecularly Imprinted Polymer/Metal Organic Framework Based Chemical Sensors

    Directory of Open Access Journals (Sweden)

    Zhenzhong Guo

    2016-10-01

    Full Text Available The present review describes recent advances in the concept of molecular imprinting using metal organic frameworks (MOF for development of chemical sensors. Two main strategies regarding the fabrication, performance and applications of recent sensors based on molecularly imprinted polymers associated with MOF are presented: molecularly imprinted MOF films and molecularly imprinted core-shell nanoparticles using MOF as core. The associated transduction modes are also discussed. A brief conclusion and future expectations are described herein.

  9. Molecularly Imprinted Polymer/Metal Organic Framework Based Chemical Sensors

    OpenAIRE

    Zhenzhong Guo; Anca Florea; Mengjuan Jiang; Yong Mei; Weiying Zhang; Aidong Zhang; Robert Săndulescu; Nicole Jaffrezic-Renault

    2016-01-01

    The present review describes recent advances in the concept of molecular imprinting using metal organic frameworks (MOF) for development of chemical sensors. Two main strategies regarding the fabrication, performance and applications of recent sensors based on molecularly imprinted polymers associated with MOF are presented: molecularly imprinted MOF films and molecularly imprinted core-shell nanoparticles using MOF as core. The associated transduction modes are also discussed. A brief conclu...

  10. Chemical sensor with oscillating cantilevered probe

    Science.gov (United States)

    Adams, Jesse D

    2013-02-05

    The invention provides a method of detecting a chemical species with an oscillating cantilevered probe. A cantilevered beam is driven into oscillation with a drive mechanism coupled to the cantilevered beam. A free end of the oscillating cantilevered beam is tapped against a mechanical stop coupled to a base end of the cantilevered beam. An amplitude of the oscillating cantilevered beam is measured with a sense mechanism coupled to the cantilevered beam. A treated portion of the cantilevered beam is exposed to the chemical species, wherein the cantilevered beam bends when exposed to the chemical species. A second amplitude of the oscillating cantilevered beam is measured, and the chemical species is determined based on the measured amplitudes.

  11. Chemical sensors based on molecularly modified metallic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Haick, Hossam [Department of Chemical Engineering and Russell Berrie Nanotechnology Institute, Technion - Israel Institute of Technology, Haifa 32000 (Israel)

    2007-12-07

    This paper presents a concise, although admittedly non-exhaustive, didactic review of some of the main concepts and approaches related to the use of molecularly modified metal nanoparticles in or as chemical sensors. This paper attempts to pull together different views and terminologies used in sensors based on molecularly modified metal nanoparticles, including those established upon electrochemical, optical, surface Plasmon resonance, piezoelectric and electrical transduction approaches. Finally, this paper discusses briefly the main advantages and disadvantages of each of the presented class of sensors. (review article)

  12. The Application of Metal Oxide Nanomaterials for Chemical Sensor Development

    Science.gov (United States)

    Xu, Jennifer C.; Hunter, Gary W.; Evans, Laura J.; VanderWal, Randy L.; Berger, Gordon M.

    2007-01-01

    NASA Glenn Research Center (GRC) has been developing miniature chemical sensors for a variety of applications including fire detection, emissions monitoring, fuel leak detection, and environmental monitoring. Smart Lick and Stick sensor technology which integrates a sensor array, electronics, telemetry, and power into one microsystem are being developed. These microsystems require low power consumption for long-term aerospace applications. One approach to decreasing power consumption is the use of nanotechnology. Nanocrystalline tin oxide (SnO2) carbon monoxide (CO) sensors developed previously by this group have been successfully used for fire detection and emissions monitoring. This presentation will briefly review the overall NASA GRC chemical sensor program and discuss our further effort in nanotechnology applications. New carbon dioxide (CO2) sensing material using doped nanocrystalline SnO2 will be discussed. Nanocrystalline SnO2 coated solid electrolyte CO2 sensors and SnO2 nanorod and nanofiber hydrogen (H2) sensors operated at reduced or room temperatures will also be discussed.

  13. Proliferation detection using a remote resonance Raman chemical sensor

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacek, A.J.; Chen, C.L.; Dougherty, D.R.

    1993-08-01

    The authors discussed the potential of the resonance Raman chemical sensor as a remote sensor that can be used for gases, liquids or solids. This spectroscopy has the fundamental advantage that it is based on optical fingerprints that are insensitive to environmental perturbations or excitation frequency. By taking advantage of resonance enhancement, the inelastic scattering cross-section can increase anywhere from 4 to 6 orders of magnitude which translates into increased sensing range or lower detection limits. It was also shown that differential cross-sections as small as 10{sup {minus}27} cm{sup 2}/sr do not preclude the use of this technique as being an important component in one`s remote-sensing arsenal. The results obtained in the early 1970s on various pollutants and the more recent work on atmospheric water cast a favorable light on the prospects for the successful development of a resonance Raman remote sensor. Currently, of the 20 CW agent-related {open_quotes}signature{close_quotes} chemicals that the authors have investigated, 18 show enhancements ranging from 3 to 6 orders of magnitude. The absolute magnitudes of the measured resonance enhanced Raman cross-sections for these 18 chemicals suggest that detection and identification of trace quantities of the {open_quotes}signature{close_quotes} chemicals, through a remote resonance Raman chemical sensor, could be achieved.

  14. Silicon nanowire field-effect chemical sensor

    NARCIS (Netherlands)

    Chen, Songyue

    2011-01-01

    This thesis describes the work that has been done on the project “Design and optimization of silicon nanowire for chemical sensing”, including Si-NW fabrication, electrical/electrochemical modeling, the application as ISFET, and the build-up of Si- NW/LOC system for automatic sample delivery. A nove

  15. MEMS device for mass market gas and chemical sensors

    Science.gov (United States)

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

    2000-08-01

    Gas and chemical sensors are used in many applications. Industrial health and safety monitors allow companies to meet OSHA requirements by detecting harmful levels of toxic or combustible gases. Vehicle emissions are tested during annual inspections. Blood alcohol breathalizers are used by law enforcement. Refrigerant leak detection ensures that the Earth's ozone layer is not being compromised. Industrial combustion emissions are also monitored to minimize pollution. Heating and ventilation systems watch for high levels of carbon dioxide (CO2) to trigger an increase in fresh air exchange. Carbon monoxide detectors are used in homes to prevent poisoning from poor combustion ventilation. Anesthesia gases are monitored during a patients operation. The current economic reality is that two groups of gas sensor technologies are competing in two distinct existing market segments - affordable (less reliable) chemical reaction sensors for consumer markets and reliable (expensive) infrared (IR) spectroscopic sensors for industrial, laboratory, and medical instrumentation markets. Presently high volume mass-market applications are limited to CO detectros and on-board automotive emissions sensors. Due to reliability problems with electrochemical sensor-based CO detectors there is a hesitancy to apply these sensors in other high volume applications. Applications such as: natural gas leak detection, non-invasive blood glucose monitoring, home indoor air quality, personal/portable air quality monitors, home fire/burnt cooking detector, and home food spoilage detectors need a sensor that is a small, efficient, accurate, sensitive, reliable, and inexpensive. Connecting an array of these next generation gas sensors to wireless networks that are starting to proliferate today creates many other applications. Asthmatics could preview the air quality of their destinations as they venture out into the day. HVAC systems could determine if fresh air intake was actually better than the air

  16. Graphene-Based Chemical Vapor Sensors for Electronic Nose Applications

    Science.gov (United States)

    Nallon, Eric C.

    An electronic nose (e-nose) is a biologically inspired device designed to mimic the operation of the olfactory system. The e-nose utilizes a chemical sensor array consisting of broadly responsive vapor sensors, whose combined response produces a unique pattern for a given compound or mixture. The sensor array is inspired by the biological function of the receptor neurons found in the human olfactory system, which are inherently cross-reactive and respond to many different compounds. The use of an e-nose is an attractive approach to predict unknown odors and is used in many fields for quantitative and qualitative analysis. If properly designed, an e-nose has the potential to adapt to new odors it was not originally designed for through laboratory training and algorithm updates. This would eliminate the lengthy and costly R&D costs associated with materiel and product development. Although e-nose technology has been around for over two decades, much research is still being undertaken in order to find new and more diverse types of sensors. Graphene is a single-layer, 2D material comprised of carbon atoms arranged in a hexagonal lattice, with extraordinary electrical, mechanical, thermal and optical properties due to its 2D, sp2-bonded structure. Graphene has much potential as a chemical sensing material due to its 2D structure, which provides a surface entirely exposed to its surrounding environment. In this configuration, every carbon atom in graphene is a surface atom, providing the greatest possible surface area per unit volume, so that electron transport is highly sensitive to adsorbed molecular species. Graphene has gained much attention since its discovery in 2004, but has not been realized in many commercial electronics. It has the potential to be a revolutionary material for use in chemical sensors due to its excellent conductivity, large surface area, low noise, and versatile surface for functionalization. In this work, graphene is incorporated into a

  17. Design Of Piezoelectric Microcantilever Chemical Sensors In COMSOL Multiphysics Area

    Directory of Open Access Journals (Sweden)

    Maziar Norouzi

    2009-05-01

    Full Text Available This paper offers an analytical modeling ofthin-filmed, multi-layer piezoelectric microcantileversthat are used as MEMS sensors. These sensors arechemical kind and use piezoelectric microcantilever.These types of microcantilevers are covered withvariety of unique probe coating. The sensor has highsensitivity with external voltage measured in mV anduses PSD1 system to indentify chemical ingredients ofmaterials. The identification of the chemical ingredientof materials is based on change in angle of microcantilever in the liquid or gas environment. Thedeflection of microcantilever results in varying voltagethat can be used to analyze materials. Analyticalsimulation using Cosmol software and theoreticalcomputations using equations will be offered in orderto determine the parameters for optimal design setting.The analytical simulation includes design of mems andCosmol software model development. The analyticalmodel of the cantilever will be analyzed and theprocess of its construction will be discussed.

  18. Chemical Sensors Based on Molecularly Imprinted Sol-Gel Materials

    Directory of Open Access Journals (Sweden)

    Franz L. Dickert

    2010-03-01

    Full Text Available The sol-gel technique is earning the worldwide attention of researchers in the field of material science, due to its versatility in synthesizing inorganic ceramic materials at mild conditions. High purity, homogeneity, controlled porosity, stable temperature and nanoscale structuring are the most remarkable features offered by this method for generating highly sensitive and selective matrices to incorporate analyte molecules. The crafting of sol-gel sensors through molecular imprinting has put great influence on the development of innovative chemical sensors, which can be seen from the growing number of publications in this field. The review provides a brief overview of sol-gel sensor applications, and discusses the contribution of molecular imprinting in exploring the new world of sensors.

  19. Durable chemical sensors based on field-effect transistors

    NARCIS (Netherlands)

    Reinhoudt, D.N.

    1995-01-01

    The design of durable chemical sensors based on field-effect transistors (FETs) is described. After modification of an ion-sensitive FET (ISFET) with a polysiloxane membrane matrix, it is possible to attach all electroactive components covalently. Preliminary results of measurements with a sodium-se

  20. Waveguide Zeeman interferometry for thin-film chemical sensors

    Energy Technology Data Exchange (ETDEWEB)

    Grace, K.M.; Shrouf, K.; Johnston, R.G.; Yang, X.; Swanson, B. [Los Alamos National Lab., NM (United States); Honkanen, S.; Ayras, P.; Peyghambarian, N. [Optical Sciences Center, Univ. of Arizona, Tucson, AZ (United States); Katila, P.; Leppihalme, M. [VTT Electronics (Finland)

    1997-10-01

    A chemical sensor is demonstrated which is based on Si{sub 3}N{sub 4} optical waveguides coated with species-selective thin films and using Zeeman interferometry as the detection technique. Relative phase change between TE and TM modes is measured. Real time and reversible response to toluene is shown with ppm level sensitivity.

  1. TOPICAL REVIEW: Biological and chemical sensors for cancer diagnosis

    Science.gov (United States)

    Simon, Elfriede

    2010-11-01

    The great challenge for sensor systems to be accepted as a relevant diagnostic and therapeutic tool for cancer detection is the ability to determine the presence of relevant biomarkers or biomarker patterns comparably to or even better than the traditional analytical systems. Biosensor and chemical sensor technologies are already used for several clinical applications such as blood glucose or blood gas measurements. However, up to now not many sensors have been developed for cancer-related tests because only a few of the biomarkers have shown clinical relevance and the performance of the sensor systems is not always satisfactory. New genomic and proteomic tools are used to detect new molecular signatures and identify which combinations of biomarkers may detect best the presence or risk of cancer or monitor cancer therapies. These molecular signatures include genetic and epigenetic signatures, changes in gene expressions, protein biomarker profiles and other metabolite profile changes. They provide new changes in using different sensor technologies for cancer detection especially when complex biomarker patterns have to be analyzed. To address requirements for this complex analysis, there have been recent efforts to develop sensor arrays and new solutions (e.g. lab on a chip) in which sampling, preparation, high-throughput analysis and reporting are integrated. The ability of parallelization, miniaturization and the degree of automation are the focus of new developments and will be supported by nanotechnology approaches. This review recaps some scientific considerations about cancer diagnosis and cancer-related biomarkers, relevant biosensor and chemical sensor technologies, their application as cancer sensors and consideration about future challenges.

  2. Odour Detection Methods: Olfactometry and Chemical Sensors

    Directory of Open Access Journals (Sweden)

    Sara Lovascio

    2011-05-01

    Full Text Available The complexity of the odours issue arises from the sensory nature of smell. From the evolutionary point of view olfaction is one of the oldest senses, allowing for seeking food, recognizing danger or communication: human olfaction is a protective sense as it allows the detection of potential illnesses or infections by taking into account the odour pleasantness/unpleasantness. Odours are mixtures of light and small molecules that, coming in contact with various human sensory systems, also at very low concentrations in the inhaled air, are able to stimulate an anatomical response: the experienced perception is the odour. Odour assessment is a key point in some industrial production processes (i.e., food, beverages, etc. and it is acquiring steady importance in unusual technological fields (i.e., indoor air quality; this issue mainly concerns the environmental impact of various industrial activities (i.e., tanneries, refineries, slaughterhouses, distilleries, civil and industrial wastewater treatment plants, landfills and composting plants as sources of olfactory nuisances, the top air pollution complaint. Although the human olfactory system is still regarded as the most important and effective “analytical instrument” for odour evaluation, the demand for more objective analytical methods, along with the discovery of materials with chemo-electronic properties, has boosted the development of sensor-based machine olfaction potentially imitating the biological system. This review examines the state of the art of both human and instrumental sensing currently used for the detection of odours. The olfactometric techniques employing a panel of trained experts are discussed and the strong and weak points of odour assessment through human detection are highlighted. The main features and the working principles of modern electronic noses (E-Noses are then described, focusing on their better performances for environmental analysis. Odour emission monitoring

  3. Carbon Nanotube Based Chemical Sensors for Space and Terrestrial Applications

    Science.gov (United States)

    Li, Jing; Lu, Yijiang

    2009-01-01

    A nanosensor technology has been developed using nanostructures, such as single walled carbon nanotubes (SWNTs), on a pair of interdigitated electrodes (IDE) processed with a silicon-based microfabrication and micromachining technique. The IDE fingers were fabricated using photolithography and thin film metallization techniques. Both in-situ growth of nanostructure materials and casting of the nanostructure dispersions were used to make chemical sensing devices. These sensors have been exposed to nitrogen dioxide, acetone, benzene, nitrotoluene, chlorine, and ammonia in the concentration range of ppm to ppb at room temperature. The electronic molecular sensing of carbon nanotubes in our sensor platform can be understood by intra- and inter-tube electron modulation in terms of charge transfer mechanisms. As a result of the charge transfer, the conductance of p-type or hole-richer SWNTs in air will change. Due to the large surface area, low surface energy barrier and high thermal and mechanical stability, nanostructured chemical sensors potentially can offer higher sensitivity, lower power consumption and better robustness than the state-of-the-art systems, which make them more attractive for defense and space applications. Combined with MEMS technology, light weight and compact size sensors can be made in wafer scale with low cost. Additionally, a wireless capability of such a sensor chip can be used for networked mobile and fixed-site detection and warning systems for military bases, facilities and battlefield areas.

  4. Plasmonics Based Harsh Environment Compatible Chemical Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Michael Carpenter

    2012-01-15

    Au-YSZ, Au-TiO{sub 2} and Au-CeO{sub 2} nanocomposite films have been investigated as a potential sensing element for high-temperature plasmonic sensing of H{sub 2}, CO, and NO{sub 2} in an oxygen containing environment. The Au-YSZ and Au-TiO{sub 2} films were deposited using PVD methods, while the CeO{sub 2} thin film was deposited by molecular beam epitaxy (MBE) and Au was implanted into the as-grown film at an elevated temperature followed by high temperature annealing to form well-defined Au nanoclusters. Each of the films were characterized by x-ray diffraction (XRD) and Rutherford backscattering spectrometry (RBS). For the gas sensing experiments, separate exposures to varying concentrations of H{sub 2}, CO, and NO{sub 2} were performed at a temperature of 500°C in oxygen backgrounds of 5.0, 10, and ~21% O{sub 2}. Changes in the localized surface plasmon resonance (LSPR) absorption peak were monitored during gas exposures and are believed to be the result of oxidation-reduction processes that fill or create oxygen vacancies in the respective metal oxides. This process affects the LSPR peak position either by charge exchange with the Au nanoparticles or by changes in the dielectric constant surrounding the particles. Hyperspectral multivariate analysis was used to gauge the inherent selectivity of the film between the separate analytes. From principal component analysis (PCA), unique and identifiable responses were seen for each of the analytes. Linear discriminant analysis (LDA) was also used on the Au-CeO{sub 2} results and showed separation between analytes as well as trends in gas concentration. Results indicate that each of the films are is selective towards O{sub 2}, H{sub 2}, CO, and NO{sub 2} in separate exposures. However, when the films were analyzed in a sensor array based experiment, ie simultaneous exposures to the target gases, PCA analysis of the combined response showed an even greater selective character towards the target gases. Combined

  5. Microfabricated Chemical Sensors for Aerospace Fire Detection Applications

    Science.gov (United States)

    Hunter, Gary W.; Neudeck, Philip G.; Fralick, Gustave; Thomas, Valarie; Makel, D.; Liu, C. C.; Ward, B.; Wu, Q. H.

    2001-01-01

    The detection of fires on-board commercial aircraft is extremely important for safety reasons. Although dependable fire detection equipment presently exists within the cabin, detection of fire within the cargo hold has been less reliable and susceptible to false alarms. A second, independent method of fire detection to complement the conventional smoke detection techniques, such as the measurement of chemical species indicative of a fire, will help reduce false alarms and improve aircraft safety. Although many chemical species are indicative of a fire, two species of particular interest are CO and CO2. This paper discusses microfabricated chemical sensor development tailored to meet the needs of fire safety applications. This development is based on progress in three types of technology: 1) Micromachining and microfabrication (Microsystem) technology to fabricate miniaturized sensors. 2) The use of nanocrystalline materials to develop sensors with improved stability combined with higher sensitivity. 3) The development of high temperature semiconductors, especially silicon carbide. The individual sensor being developed and their level of maturity will be presented.

  6. Nanostructured conjugated polymers in chemical sensors: synthesis, properties and applications.

    Science.gov (United States)

    Correa, D S; Medeiros, E S; Oliveira, J E; Paterno, L G; Mattoso, Luiz C

    2014-09-01

    Conjugated polymers are organic materials endowed with a π-electron conjugation along the polymer backbone that present appealing electrical and optical properties for technological applications. By using conjugated polymeric materials in the nanoscale, such properties can be further enhanced. In addition, the use of nanostructured materials makes possible miniaturize devices at the micro/nano scale. The applications of conjugated nanostructured polymers include sensors, actuators, flexible displays, discrete electronic devices, and smart fabric, to name a few. In particular, the use of conjugated polymers in chemical and biological sensors is made feasible owning to their sensitivity to the physicochemical conditions of its surrounding environment, such as chemical composition, pH, dielectric constant, humidity or even temperature. Subtle changes in these conditions bring about variations on the electrical (resistivity and capacitance), optical (absorptivity, luminescence, etc.), and mechanical properties of the conjugated polymer, which can be precisely measured by different experimental methods and ultimately associated with a specific analyte and its concentration. The present review article highlights the main features of conjugated polymers that make them suitable for chemical sensors. An especial emphasis is given to nanostructured sensors systems, which present high sensitivity and selectivity, and find application in beverage and food quality control, pharmaceutical industries, medical diagnosis, environmental monitoring, and homeland security, and other applications as discussed throughout this review.

  7. Photonic crystal fiber based chloride chemical sensors for corrosion monitoring

    Science.gov (United States)

    Wei, Heming; Tao, Chuanyi; Krishnaswamy, Sridhar

    2016-04-01

    Corrosion of steel is one of the most important durability issues in reinforced concrete (RC) structures because aggressive ions such as chloride ions permeate concrete and corrode steel, consequently accelerating the destruction of structures, especially in marine environments. There are many practical methods for corrosion monitoring in RC structures, mostly focusing on electrochemical-based sensors for monitoring the chloride ion which is thought as one of the most important factors resulting in steel corrosion. In this work, we report a fiber-optic chloride chemical sensor based on long period gratings inscribed in a photonic crystal fiber (PCF) with a chloride sensitive thin film. Numerical simulation is performed to determine the characteristics and resonance spectral response versus the refractive indices of the analyte solution flowing through into the holes in the PCF. The effective refractive index of the cladding mode of the LPGs changes with variations of the analyte solution concentration, resulting in a shift of the resonance wavelength, hence providing the sensor signal. This fiber-optic chemical sensor has a fast response, is easy to prepare and is not susceptible to electromagnetic environment, and can therefore be of use for structural health monitoring of RC structures subjected to such aggressive environments.

  8. Nanostructure Engineered Chemical Sensors for Hazardous Gas and Vapor Detection

    Science.gov (United States)

    Li, Jing; Lu, Yijiang

    2005-01-01

    A nanosensor technology has been developed using nanostructures, such as single walled carbon nanotubes (SWNTs) and metal oxides nanowires or nanobelts, on a pair of interdigitated electrodes (IDE) processed with a silicon based microfabrication and micromachining technique. The IDE fingers were fabricated using thin film metallization techniques. Both in-situ growth of nanostructure materials and casting of the nanostructure dispersions were used to make chemical sensing devices. These sensors have been exposed to hazardous gases and vapors, such as acetone, benzene, chlorine, and ammonia in the concentration range of ppm to ppb at room temperature. The electronic molecular sensing in our sensor platform can be understood by electron modulation between the nanostructure engineered device and gas molecules. As a result of the electron modulation, the conductance of nanodevice will change. Due to the large surface area, low surface energy barrier and high thermal and mechanical stability, nanostructured chemical sensors potentially can offer higher sensitivity, lower power consumption and better robustness than the state-of-the-art systems, which make them more attractive for defense and space applications. Combined with MEMS technology, light weight and compact size sensors can be made in wafer scale with low cost.

  9. Semiconductor Quantum Dots in Chemical Sensors and Biosensors

    OpenAIRE

    Nikos Chaniotakis; Frasco, Manuela F.

    2009-01-01

    Quantum dots are nanometre-scale semiconductor crystals with unique optical properties that are advantageous for the development of novel chemical sensors and biosensors. The surface chemistry of luminescent quantum dots has encouraged the development of multiple probes based on linked recognition molecules such as peptides, nucleic acids or small-molecule ligands. This review overviews the design of sensitive and selective nanoprobes, ranging from the type of target molecules to the optical ...

  10. Wireless Chemical Sensor and Sensing Method for Use Therewith

    Science.gov (United States)

    Woodard, Stanley E. (Inventor); Oglesby, Donald M. (Inventor); Taylor, Bryant D. (Inventor)

    2016-01-01

    A wireless chemical sensor includes an electrical conductor and a material separated therefrom by an electric insulator. The electrical conductor is an unconnected open-circuit shaped for storage of an electric field and a magnetic field. In the presence of a time-varying magnetic field, the first electrical conductor resonates to generate harmonic electric and magnetic field responses. The material is positioned at a location lying within at least one of the electric and magnetic field responses so-generated. The material changes in electrical conductivity in the presence of a chemical-of-interest.

  11. Supramolecular Derivation of Graphene Nanomaterials for Chemical Sensors

    DEFF Research Database (Denmark)

    Olsen, Gunnar

    , which have long been used for chemical sensing, graphene-like, materials can be endowed with increasing selectivity to form better and cheaper sensing composite materials. In this Ph.D. project, reduced graphene oxide (RGO) has been covalently functionalized with supramolecular moieties to create active...... sensing materials. Two different strategies have been applied to achieve specific functionalization: The first approach consisted of covalently attaching chemically resistant supramolecular moieties, in the present work crown-ethers to graphene oxide (GO); the functionalized GO was then reduced chemically......With properties such as high surface area, high conductivity, and low production cost with easy up-scaling, graphene-like materials provide a promising support for many applications, one of which is for chemical sensors. By functionalization with molecular receptors such as supramolecular moieties...

  12. Chemometrics review for chemical sensor development, task 7 report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-05-01

    This report, the seventh in a series on the evaluation of several chemical sensors for use in the U.S. Department of Energy`s (DOE`s) site characterization and monitoring programs, concentrates on the potential use of chemometrics techniques in analysis of sensor data. Chemometrics is the chemical discipline that uses mathematical, statistical, and other methods that employ formal logic to: design or select optimal measurement procedures and experiments and provide maximum relevant chemical information by analyzing chemical data. The report emphasizes the latter aspect. In a formal sense, two distinct phases are in chemometrics applications to analytical chemistry problems: (1) the exploratory data analysis phase and (2) the calibration and prediction phase. For use in real-world problems, it is wise to add a third aspect - the independent validation and verification phase. In practical applications, such as the ERWM work, and in order of decreasing difficulties, the most difficult tasks in chemometrics are: establishing the necessary infrastructure (to manage sampling records, data handling, and data storage and related aspects), exploring data analysis, and solving calibration problems, especially for nonlinear models. Chemometrics techniques are different for what are called zeroth-, first-, and second-order systems, and the details depend on the form of the assumed functional relationship between the measured response and the concentrations of components in mixtures. In general, linear relationships can be handled relatively easily, but nonlinear relationships can be difficult.

  13. Soil chemical sensor and precision agricultural chemical delivery system and method

    Energy Technology Data Exchange (ETDEWEB)

    Colburn, J.W. Jr.

    1991-07-23

    A real time soil chemical sensor and precision agricultural chemical delivery system includes a plurality of ground-engaging tools in association with individual soil sensors which measure soil chemical levels. The system includes the addition of a solvent which rapidly saturates the soil/tool interface to form a conductive solution of chemicals leached from the soil. A multivalent electrode, positioned within a multivalent frame of the ground-engaging tool, applies a voltage or impresses a current between the electrode and the tool frame. A real-time soil chemical sensor and controller senses the electrochemical reaction resulting from the application of the voltage or current to the leachate, measures it by resistivity methods, and compares it against pre-set resistivity levels for substances leached by the solvent. Still greater precision is obtained by calibrating for the secondary current impressed through solvent-less soil. The appropriate concentration is then found and the servo-controlled delivery system applies the appropriate amount of fertilizer or agricultural chemicals substantially in the location from which the soil measurement was taken. 5 figures.

  14. Pd/CeO2/SiC Chemical Sensors

    Science.gov (United States)

    Lu, Weijie; Collins, W. Eugene

    2005-01-01

    The incorporation of nanostructured interfacial layers of CeO2 has been proposed to enhance the performances of Pd/SiC Schottky diodes used to sense hydrogen and hydrocarbons at high temperatures. If successful, this development could prove beneficial in numerous applications in which there are requirements to sense hydrogen and hydrocarbons at high temperatures: examples include monitoring of exhaust gases from engines and detecting fires. Sensitivity and thermal stability are major considerations affecting the development of high-temperature chemical sensors. In the case of a metal/SiC Schottky diode for a number of metals, the SiC becomes more chemically active in the presence of the thin metal film on the SiC surface at high temperature. This increase in chemical reactivity causes changes in chemical composition and structure of the metal/SiC interface. The practical effect of the changes is to alter the electronic and other properties of the device in such a manner as to degrade its performance as a chemical sensor. To delay or prevent these changes, it is necessary to limit operation to a temperature CeO2 films is based partly on the observation that nanostructured materials in general have potentially useful electrical properties, including an ability to enhance the transfer of electrons. In particular, nanostructured CeO2, that is CeO2 with nanosized grains, has shown promise for incorporation into hightemperature electronic devices. Nanostructured CeO2 films can be formed on SiC and have been shown to exhibit high thermal stability on SiC, characterized by the ability to withstand temperatures somewhat greater than 700 C for limited times. The exchanges of oxygen between CeO2 and SiC prevent the formation of carbon and other chemical species that are unfavorable for operation of a SiC-based Schottky diode as a chemical sensor. Consequently, it is anticipated that in a Pd/CeO2/SiC Schottky diode, the nanostructured interfacial CeO2 layer would contribute to

  15. Feature Selection for Chemical Sensor Arrays Using Mutual Information

    Science.gov (United States)

    Wang, X. Rosalind; Lizier, Joseph T.; Nowotny, Thomas; Berna, Amalia Z.; Prokopenko, Mikhail; Trowell, Stephen C.

    2014-01-01

    We address the problem of feature selection for classifying a diverse set of chemicals using an array of metal oxide sensors. Our aim is to evaluate a filter approach to feature selection with reference to previous work, which used a wrapper approach on the same data set, and established best features and upper bounds on classification performance. We selected feature sets that exhibit the maximal mutual information with the identity of the chemicals. The selected features closely match those found to perform well in the previous study using a wrapper approach to conduct an exhaustive search of all permitted feature combinations. By comparing the classification performance of support vector machines (using features selected by mutual information) with the performance observed in the previous study, we found that while our approach does not always give the maximum possible classification performance, it always selects features that achieve classification performance approaching the optimum obtained by exhaustive search. We performed further classification using the selected feature set with some common classifiers and found that, for the selected features, Bayesian Networks gave the best performance. Finally, we compared the observed classification performances with the performance of classifiers using randomly selected features. We found that the selected features consistently outperformed randomly selected features for all tested classifiers. The mutual information filter approach is therefore a computationally efficient method for selecting near optimal features for chemical sensor arrays. PMID:24595058

  16. Nanowire sensors and arrays for chemical/biomolecule detection

    Science.gov (United States)

    Yun, Minhee; Lee, Choonsup; Vasquez, Richard P.; Ramanathan, K.; Bangar, M. A.; Chen, W.; Mulchandan, A.; Myung, N. V.

    2005-01-01

    We report electrochemical growth of single nanowire based sensors using e-beam patterned electrolyte channels, potentially enabling the controlled fabrication of individually addressable high density arrays. The electrodeposition technique results in nanowires with controlled dimensions, positions, alignments, and chemical compositions. Using this technique, we have fabricated single palladium nanowires with diameters ranging between 75 nm and 300 nm and conducting polymer nanowires (polypyrrole and polyaniline) with diameters between 100 nm and 200 nm. Using these single nanowires, we have successfully demonstrated gas sensing with Pd nanowires and pH sensing with polypirrole nanowires.

  17. Graphene Electronic Device Based Biosensors and Chemical Sensors

    Science.gov (United States)

    Jiang, Shan

    Two-dimensional layered materials, such as graphene and MoS2, are emerging as an exciting material system for a new generation of atomically thin electronic devices. With their ultrahigh surface to volume ratio and excellent electrical properties, 2D-layered materials hold the promise for the construction of a generation of chemical and biological sensors with unprecedented sensitivity. In my PhD thesis, I mainly focus on graphene based electronic biosensors and chemical sensors. In the first part of my thesis, I demonstrated the fabrication of graphene nanomesh (GNM), which is a graphene thin film with a periodic array of holes punctuated in it. The periodic holes introduce long periphery active edges that provide a high density of functional groups (e.g. carboxylic groups) to allow for covalent grafting of specific receptor molecules for chemical and biosensor applications. After covalently functionalizing the GNM with glucose oxidase, I managed to make a novel electronic sensor which can detect glucose as well as pH change. In the following part of my thesis I demonstrate the fabrication of graphene-hemin conjugate for nitric oxide detection. The non-covalent functionalization through pi-pi stacking interaction allows reliable immobilization of hemin molecules on graphene without damaging the graphene lattice to ensure the highly sensitive and specific detection of nitric oxide. The graphene-hemin nitric oxide sensor is capable of real-time monitoring of nitric oxide concentrations, which is of central importance for probing the diverse roles of nitric oxide in neurotransmission, cardiovascular systems, and immune responses. Our studies demonstrate that the graphene-hemin sensors can respond rapidly to nitric oxide in physiological environments with sub-nanomolar sensitivity. Furthermore, in vitro studies show that the graphene-hemin sensors can be used for the detection of nitric oxide released from macrophage cells and endothelial cells, demonstrating their

  18. Development of chemical sensors by using beta emitters

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, H. J; Yu, S. K.; Yoon, M. O.; Park, K. S.; Rhim, G. J. [Kyung Hee University, Seoul (Korea)

    2000-04-01

    The objective of this project is development of core techniques for fabrication of biosensor. This includes a method for immobilization of biologically active molecules, a method for labelling target molecules with beta emitter, and a detection method based on beta counting. A radioimmuno-sensor for detection of DNA antibody, self-assembled monolayers of {omega}-carboxylated thiol molecules such as thioctic acid and 12-mercaptododecanoic acid were used in combination with chemical coupling methods. EDC (1 - ethyl - 3 [3 - (dimethylamino)propyl] carbodiimide) and NHS (N - hydroxy - succinimide) were used as coupling reagents to induce amide bond formation between the COOH group on the sensor surface and the -NH{sub 2} group on the antibody. Various experimental conditions such as COOH concentration, immobilization pH, reaction times etc, have been examined to establish optimum conditions for efficient immobilization of the antibody. Efficient labeling of the target antigen, DNA, with a beta emitter, {sup 35}S, was achieved by using the polymerase chain reaction (PCR) method. Detection of sensing signal from antigens that are selectively bound to the surface of the DNA radioimmuno-sensor has been accomplished by use of the beta counting method. According to the present results, efficient immobilization of the antibody is possible at very low antibody concentration below or equal to 0.1 mg/mL with detection limit reaching as low as 10{sup -11} M bp DNA concentration. 25 refs., 14 figs. (Author)

  19. Solubility properties of siloxane polymers for chemical sensors

    Energy Technology Data Exchange (ETDEWEB)

    Grate, J.W. [Pacific Northwest Lab., Richland, WA (United States); Abraham, M.H. [University College, London (United Kingdom)

    1995-05-01

    This paper discusses the factors governing the sorption of vapors by organic polymers. The principles have been applied in the past for designing and selecting polymers for acoustic wave sensors; however they apply equally well to sorption of vapors by polymers used on optical chemical sensors. A set of solvation parameters (a table is presented for various organic vapors) have been developed that describe the particular solubility properties of individual solute molecules; they are used in linear solvation energy relationships (LSER) that model the sorption process. LSER coefficients are tabulated for five polysiloxanes; so are individual interaction terms for each of the 5 polymers. Dispersion interactions play a major role in determining overall partition coefficients; the log L{sup 16} (gas-liquid partition coefficient of solute on hexadecane) value of vapors are important in determining overall sorption. For the detection of basic vapors such as organophosphates, a hydrogen-bond acidic polymers will be most effective at sorbing them. Currently, fiber optic sensors are being developed where the cladding serves as a sorbent layer to collect and concentrate analyte vapors, which will be detected and identified spectroscopically. These solubility models will be used to design the polymers for the cladding for particular vapors.

  20. Very Large Chemical Sensor Array for Mimicking Biological Olfaction

    Science.gov (United States)

    Beccherelli, R.; Zampetti, E.; Pantalei, S.; Bernabei, M.; Persaud, K. C.

    2009-05-01

    Olfactory receptor neurons (ORN) in the mammalian olfactory system, transduce molecular properties of the odorants into electrical signals and project these into the olfactory bulb (OB). In the biological system several millions of receptor neurons of a few hundred types create redundancy and the massive convergence of the ORNs to the OB, is thought to enhance the sensitivity and selectivity of the system. To explore this concept, the NEUROCHEM project will build a polymeric chemical sensor array consisting of 216 (65536) sensors with tens of different types. To interface such a large sensor array, a topological array configuration with n rows and m columns, has been adopted, to reduce the total wiring connections to n+m. A method of addressing a single element in the array in isolation of the rest of the network has been developed. Over the array ten different conductive polymers with different sensing characteristics will be deposited by means of electrodeposition and inkjet printing. A smaller prototype of 64 elements has been investigated and the results are here reported and discussed.

  1. Single walled carbon nanotubes functionally adsorbed to biopolymers for use as chemical sensors

    Science.gov (United States)

    Johnson, Jr., Alan T.; Gelperin, Alan; Staii, Cristian

    2011-07-12

    Chemical field effect sensors comprising nanotube field effect devices having biopolymers such as single stranded DNA functionally adsorbed to the nanotubes are provided. Also included are arrays comprising the sensors and methods of using the devices to detect volatile compounds.

  2. Organic/Inorganic Hybrid Nanostructures for Chemical Plasmonic Sensors

    Science.gov (United States)

    Chang, Sehoon

    2011-12-01

    The work presented in this dissertation suggests novel design of chemical plasmonic sensors which have been developed based on Localized Surface Plasmon Resonance (LSPR), and Surface-enhanced Raman scattering (SERS) phenomena. The goal of the study is to understand the SERS phenomena for 3D hybrid (organic/inorganic) templates and to design of the templates for trace-level detection of selected chemical analytes relevant to liquid explosives and hazardous chemicals. The key design criteria for the development of the SERS templates are utilizing selective polymeric nanocoatings within cylindrical nanopores for promoting selective adsorption of chemical analyte molecules, maximizing specific surface area, and optimizing concentration of hot spots with efficient light interaction inside nanochannels. The organic/inorganic hybrid templates are optimized through a comprehensive understanding of the LSPR properties of the gold nanoparticles, gold nanorods, interaction of light with highly porous alumina template, and the choice of physical and chemical attributes of the selective coating. Furthermore, novel method to assemble silver nanoparticles in 3D as the active SERS-active substrate has been demonstrated by uniform, in situ growth of silver nanoparticles from electroless deposited silver seeds excluding any adhesive polymer layer on template. This approach can be the optimal for SERS sensing applications because it is not necessary to separate the Raman bands of the polyelectrolyte binding layer from those of the desired analyte. The fabrication method is an efficient, simple and fast way to assemble nanoparticles into 3D nanostructures. Addressable Raman markers from silver nanowire crossbars with silver nanoparticles are also introduced and studied. Assembly of silver nanowire crossbar structure is achieved by simple, double-step capillary transfer lithography. The on/off SERS properties can be observed on silver nanowire crossbars with silver nanoparticles

  3. Fabrication of SAW Sensor for Detecting Chemical Agent

    Institute of Scientific and Technical Information of China (English)

    J H Lee; B S Joo; J S Huh; D D Lee

    2006-01-01

    SAW sensors using five different types of polymer to detect of chemical agents (DMMP, CH3CN, CH2Cl2, DCP)have been fabricated and its gas response characteristics were extensively investigated. The polymers used as the sensing material are polyisobutylene (PIB), polyepichlorohydrin (PECH), polydimethylsiloxane (PDMS), polyisoprene(PIP) and polybutadiene(PBD). Their thin films were coated on quartz substrate by spin coating technique. Three types of simulants gases, dimethylmethylphosphonate(DMMP), acetonitrile (CH3CN) and dichloromethane(CH2Cl2), dichloropentane(DCP) were used as target gases, instead of the real nerve, blood, choking and vesicant agents. After spin coating of PIB and PECH, the substrates were heated to 65℃ with N2 flow for 1 h to remove the cyclohexane and ethylacetate which was used as solvent.PDMS was heated to 75℃ with N2 flow for 2 h to remove the ethylacetate which was used as solvent. PBD and PIP on the substrate were heated to 60℃ with N2 flow for 1 h to remove the benzen which was used as solvent. The sensing characteristics of the SAW sensors were measured by using E-5061A network analyzer.

  4. Chemical gas sensors and the characterization, monitoring and sensor technology needs of the US Department of Energy

    Energy Technology Data Exchange (ETDEWEB)

    Bastiaans, G.J.; Haas, W.J. Jr.; Junk, G.A.

    1993-10-01

    The Office of Technology Development within the Dept. of Energy (DOE) has the responsibility of providing new technologies to aid the environmental restoration and waste management (ER/WM) activities of the DOE. There is a perception that application and judicious development of chemical sensor technologies could result in large cost savings and reduced risk to the health and safety of ER/WM personnel. A number of potential gas sensor applications which exist within DOE ER/WM operations are described. The capabilities of several chemical sensor technologies and their potential to meet the needs of ER/WM applications in the present or near term future are discussed.

  5. Semiconductor device-based sensors for gas, chemical, and biomedical applications

    CERN Document Server

    Ren, Fan

    2011-01-01

    Sales of U.S. chemical sensors represent the largest segment of the multi-billion-dollar global sensor market, which includes instruments for chemical detection in gases and liquids, biosensors, and medical sensors. Although silicon-based devices have dominated the field, they are limited by their general inability to operate in harsh environments faced with factors such as high temperature and pressure. Exploring how and why these instruments have become a major player, Semiconductor Device-Based Sensors for Gas, Chemical, and Biomedical Applications presents the latest research, including or

  6. Feasibility of a Stack Integrated SOFC Optical Chemical Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Michael A. Carpenter

    2007-09-30

    The DOE-NETL Innovative Concepts (IC) phase II program investigated the feasibility of harsh environment compatible chemical sensors based on monitoring the surface plasmon resonance (SPR) bands of metal nanoparticle doped YSZ nano-cermets, as a function of fuel concentrations, impurities e.g. CO and temperature(500-900 C). In particular, Au nanoparticles (AuNPs) exhibit a strong surface plasmon resonance (SPR) band whose shape and spectral position is not only highly dependent on the refractive index of the host medium but also on chemical reactions at the interface between the metal and the surrounding environment. Studies have been completed on the oxygen and temperature dependence of the SPR band of the AuNPs, CO sensing studies, oxygen/hydrogen titration experiments, ethanol sensing studies and finally NO{sub 2} sensing studies. Reversible changes in the SPR band are observed for all chemical exposure studies with the sensing mechanism being determined by the oxidative or reductive properties of the exposure gases. Reactions which remove charge from the AuNPs was observed to cause a redshift in the SPR band, while charge donation to the AuNPs causes a blue shift in the SPR band. CO, hydrogen and ethanol in air mixtures were all reductive in nature as they reacted with the YSZ bound oxygen anions forming CO{sub 2} or H{sub 2}O thus ultimately inducing charge donation to the AuNPs and a blue shift in the SPR band. While NO{sub 2} and oxygen were oxidative and induced the production of YSZ bound oxygen anions, charge removal from the AuNPs and a redshift in the SPR band.

  7. Toward the Realization of a Compact Chemical Sensor Platform using Quantum Cascade Lasers

    Science.gov (United States)

    2015-09-01

    ARL-RP-0550 ● SEP 2015 US Army Research Laboratory Toward the Realization of a Compact Chemical Sensor Platform using Quantum...ARL-RP-0550 ● SEP 2015 US Army Research Laboratory Toward the Realization of a Compact Chemical Sensor Platform using Quantum Cascade...Lasers by Ellen L Holthoff, Logan S Marcus, and Paul M Pellegrino Sensors and Electron Devices Directorate, ARL A reprint from Proc

  8. Wearable chemical sensing – sensor design and sampling techniques for real-time sweat analysis

    OpenAIRE

    2014-01-01

    Wearable chemical sensors have the potential to provide new methods of non-invasive physiological measurement. The nature of chemical sensors involves an active surface where a chemical reaction must occur to elicit a response. This adds complexity to a wearable system which creates challenges in the design of a reliable long-term working system. This work presents the design of a real-time sweat sensing platform to analyse sweat loss and composition. Sampling methods have an impact on...

  9. Tapered optical fiber sensor for chemical pollutants detection in seawater

    Science.gov (United States)

    Irigoyen, Maite; Sánchez-Martin, Jose Antonio; Bernabeu, Eusebio; Zamora, Alba

    2017-04-01

    Three tapered silica optical fibers, uncoated and coated with metallic (Al or Cu) and dielectric layers (TiO2), are employed to determine the presence of oil and Hazardous and Noxious Substances (HNS from now on) in water, by means of the measurement of their spectral transmittance. With our experimental assembly, the presence of oil and HNS spills can be detected employing the three different kinds of tapers, since the complete range of refractive indices of the pollutants (1.329–1.501) is covered with these tapers. The most suitable spectral range to detect the presence of a chemical pollutant in seawater has been identified and a complete spectral characterization of the three types of optical fiber tapers has been carried out. The results obtained show that, in general terms, these devices working together can be employed for the early detection of oil and HNS spills in seawater in a marine industrial environment. These sensors have many advantages, such as its low cost, its simplicity and versatility (with interesting properties as quick response and repeatability), and especially that they can be self-cleaned with seawater in motion.

  10. Development and Application of Microfabricated Chemical Gas Sensors For Aerospace Applications

    Science.gov (United States)

    Hunter, G. W.; Neudeck, P. G.; Fralick, G.; Thomas, V.; Liu, C. C.; Wu, Q. H.; Sawayda, M. S.; Jin, A.; Hammond, J.; Makel, D.; Hall, G.

    1990-01-01

    Aerospace applications require the development of chemical sensors with capabilities beyond those of commercially available sensors. In particular, factors such as minimal sensor size, weight, and power consumption are particularly important. Development areas which have potential aerospace applications include launch vehicle leak detection, engine health monitoring and control, and fire detection. Sensor development for these applications is based on progress in three types of technology: 1) Micromachining and microfabrication (Microsystem) technology to fabricate miniaturized sensors. 2) The use of nanocrystalline materials to develop sensors with improved stability combined with higher sensitivity. 3) The development of high temperature semiconductors, especially silicon carbide. Sensor development for each application involves its own challenges in the fields of materials science and fabrication technology. This paper discusses the needs of space applications and the point-contact sensor technology being developed to address these needs. Sensors to measure hydrogen, hydrocarbons, nitrogen oxides (Nox, carbon monoxide, oxygen, and carbon dioxide are being developed. A description is given of each sensor type and its present stage of development. Demonstration and application these sensor technologies will be described. The demonstrations range from use of a microsystem based hydrogen sensor on the Shuttle to engine demonstration of a nanocrystalline based sensor for NO, detection. It is concluded that microfabricated sensor technology has significant potential for use in a range of aerospace applications.

  11. Field-effect transistor chemical sensors of single nanoribbon of copper phthalocyanine

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Copper phthalocyanine (CuPc) nanoribbon field-effect transistors were implemented as chemical sensors. They showed fast response and high reversibility in the detection of the tetrahydrofuran atmosphere at room temperature. The drain current of the field-effect transistor sensor decreased from 6.7 to 0.2 nA when the transistor was measured under the tetrahydrofuran atmosphere. The sensor was self-refreshable in a few minutes. These results demonstrate that the organic single crystalline nanoribbon transistors could effectively act as chemical sensors.

  12. Development of Low-cost Chemical and Micromechanical Sensors Based on Thick-film,Thin-film and Electroplated Films

    Institute of Scientific and Technical Information of China (English)

    Wenmin Qu; Kurt Drescher

    2000-01-01

    Various films could be used as sensing materials or as constructional materials for the fabrication of chemical and micromechanical sensors. To illustrate this potential, three sensors fabricated by very different film deposition technologies are given as examples. The sensors are a humidity sensor in thickfilm technology, a multi-functional gas sensor in thin-film technology and a three-dimensional acceleration sensor chip manufactured by electroplating techniques. Design, fabrication and characterisation of these sensors are described in this paper.

  13. Synthesis of Metal Oxide Nanomaterials for Chemical Sensors by Molecular Beam Epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Nandasiri, Manjula I.; Kuchibhatla, Satyanarayana V N T; Thevuthasan, Suntharampillai

    2013-12-01

    Since the industrial revolution, detection and monitoring of toxic matter, chemical wastes, and air pollutants has become an important environmental issue. Thus, it leads to the development of chemical sensors for various environmental applications. The recent disastrous oil spills over the near-surface of ocean due to the offshore drilling emphasize the use of chemical sensors for prevention and monitoring of the processes that might lead to these mishaps.1, 2 Chemical sensors operated on a simple principle that the sensing platform undergoes a detectable change when exposed to the target substance to be sensed. Among all the types of chemical sensors, solid state gas sensors have attracted a great deal of attention due to their advantages such as high sensitivity, greater selectivity, portability, high stability and low cost.3, 4 Especially, semiconducting metal oxides such as SnO2, TiO2, and WO3 have been widely used as the active sensing platforms in solid state gas sensors.5 For the enhanced properties of solid state gas sensors, finding new sensing materials or development of existing materials will be needed. Thus, nanostructured materials such as nanotubes,6-8 nanowires,9-11 nanorods,12-15 nanobelts,16, 17 and nano-scale thin films18-23 have been synthesized and studied for chemical sensing applications.

  14. Heat-activated Plasmonic Chemical Sensors for Harsh Environments

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, Michael [SUNY Polytechnic Inst., Albany, NY (United States); Oh, Sang-Hyun [Univ. of Minnesota, Minneapolis, MN (United States)

    2015-12-01

    sensing paradigm with PCA analysis and wavelength down selection offers a novel path towards simplification and integration of plasmonic-based sensing methods using selected wavelengths rather than a full spectral analysis. Integration efforts were designed and modeled for thermal and mass transport considerations by UTAS which led to the 3D printing of scaled models that would serve as the housing for the alternative energy harvesting plasmonic chemical sensor design developed by CNSE.

  15. Application and state of development for remote chemical sensors in environmental monitoring: A literature review

    Energy Technology Data Exchange (ETDEWEB)

    Schabron, J.F.; Niss, N.D.; Hart, B.K.

    1991-09-01

    A study was performed on chemical sensor technology currently available and under development. The information was compiled into a format wherein information on the sensors is listed in a comparable manner. An introductory section is provided to illustrate the regulatory environment in which such sensor technology will be used. This information should allow corporations or federal agencies ready access to useful information for the potential licensing of sensor technology for commercial development or specific environmental monitoring operations. Although every attempt was made to identify as many chemical sensors as possible, we recognize that some may be missed inadvertently. The accuracy of the information provided by the various sources regarding the state of development for the various sensors was not verified. Judgments or opinions regarding the actual state of development or utility of these devices are not included in this report. However, we feel that this report accurately reflects the state of the art at the present time.

  16. Application and state of development for remote chemical sensors in environmental monitoring: A literature review

    Energy Technology Data Exchange (ETDEWEB)

    Schabron, J.F.; Niss, N.D.; Hart, B.K.

    1991-09-01

    A study was performed on chemical sensor technology currently available and under development. The information was compiled into a format wherein information on the sensors is listed in a comparable manner. As introductory section is provided to illustrate the regulatory environment in which such sensor technology will be used. This information should allow corporations or federal agencies ready access to useful information for the potential licensing of sensor technology for commercial development or specific environmental monitoring operations. Although every attempt was made to identify as many chemical sensors as possible, we recognize that some may be missed inadvertently. The accuracy of the information provided by the various sources regarding the state of development for the various sensors was not verified. Judgments or opinions regarding the actual state of development or utility of these devices are not included in this report. However, we feel that this report accurately reflects the state of the art at the present time.

  17. ROC-curve approach for determining the detection limit of a field chemical sensor.

    Science.gov (United States)

    Fraga, Carlos G; Melville, Angela M; Wright, Bob W

    2007-03-01

    The detection limit of a field chemical sensor under realistic operating conditions is determined by receiver operator characteristic (ROC) curves. The chemical sensor is an ion mobility spectrometry (IMS) device used to detect a chemical marker in diesel fuel. The detection limit is the lowest concentration of the marker in diesel fuel that obtains the desired true-positive probability (TPP) and false-positive probability (FPP). A TPP of 0.90 and a FPP of 0.10 were selected as acceptable levels for the field sensor in this study. The detection limit under realistic operating conditions is found to be between 2 to 4 ppm (w/w). The upper value is the detection limit under challenging conditions. The ROC-based detection limit is very reliable because it is determined from multiple and repetitive sensor analyses under realistic circumstances. ROC curves also clearly illustrate and gauge the effects data preprocessing and sampling environments have on the sensor's detection limit.

  18. Nano-based chemical sensor array systems for uninhabited ground and airborne vehicles

    Science.gov (United States)

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

    2009-03-01

    In a time when homemade explosive devices are being used against soldiers and in the homeland security environment, it is becoming increasingly evident that there is an urgent need for high-tech chemical sensor packages to be mounted aboard ground and air vehicles to aid soldiers in determining the location of explosive devices and the origin of bio-chemical warfare agents associated with terrorist activities from a safe distance. Current technologies utilize relatively large handheld detection systems that are housed on sizeable robotic vehicles. Research and development efforts are underway at the Army Aviation & Missile Research, Development, and Engineering Center (AMRDEC) to develop novel and less expensive nano-based chemical sensors for detecting explosives and chemical agents used against the soldier. More specifically, an array of chemical sensors integrated with an electronics control module on a flexible substrate that can conform to and be surface-mounted to manned or unmanned vehicles to detect harmful species from bio-chemical warfare and other explosive devices is being developed. The sensor system under development is a voltammetry-based sensor system capable of aiding in the detection of any chemical agent and in the optimization of sensor microarray geometry to provide nonlinear Fourier algorithms to characterize target area background (e.g., footprint areas). The status of the research project is reviewed in this paper. Critical technical challenges associated with achieving system cost, size, and performance requirements are discussed. The results obtained from field tests using an unmanned remote controlled vehicle that houses a CO2/chemical sensor, which detects harmful chemical agents and wirelessly transmits warning signals back to the warfighter, are presented. Finally, the technical barriers associated with employing the sensor array system aboard small air vehicles will be discussed.

  19. Application of Photocured Polymer Ion Selective Membranes for Solid-State Chemical Sensors

    Directory of Open Access Journals (Sweden)

    Natalia Abramova

    2015-06-01

    Full Text Available Application of conducting polymers with additional functional groups for a solid contact formation and photocurable membranes as sensitive elements of solid-state chemical sensors is discussed. Problems associated with application of UV-curable polymers for sensors are analyzed. A method of sensor fabrication using copolymerized conductive layer and sensitive membrane is presented and the proof of concept is confirmed by two examples of solid-contact electrodes for Ca ions and pH.

  20. Using Fisher Information Criteria for Chemical Sensor Selection via Convex Optimization Methods

    Science.gov (United States)

    2016-11-16

    best sensors after an optimization procedure. Due to the positive definite nature of the Fisher information matrix, convex optimization may be used to...parametrized to select the best sensors after an optimization procedure. Due to the positive definite nature of the Fisher information matrix, convex op...Naval Research Laboratory Washington, DC 20375-5320 NRL/MR/6180--16-9711 Using Fisher Information Criteria for Chemical Sensor Selection via Convex

  1. Designing multifunctional chemical sensors using Ni and Cu doped carbon nanotubes

    DEFF Research Database (Denmark)

    Mowbray, Duncan; García Lastra, Juan Maria; Thygesen, Kristian Sommer;

    2010-01-01

    We demonstrate a “bottom up” approach to the computational design of a multifunctional chemical sensor. General techniques are employed for describing the adsorption coverage and resistance properties of the sensor based on density functional theory and non-equilibrium Green's function methodolog...... methodologies, respectively. Specifically, we show how Ni and Cu doped metallic (6,6) single-walled carbon nanotubes may work as effective multifunctional sensors for both CO and NH3....

  2. Carbon Nanostructure-Based Field-Effect Transistors for Label-Free Chemical/Biological Sensors

    Directory of Open Access Journals (Sweden)

    PingAn Hu

    2010-05-01

    Full Text Available Over the past decade, electrical detection of chemical and biological species using novel nanostructure-based devices has attracted significant attention for chemical, genomics, biomedical diagnostics, and drug discovery applications. The use of nanostructured devices in chemical/biological sensors in place of conventional sensing technologies has advantages of high sensitivity, low decreased energy consumption and potentially highly miniaturized integration. Owing to their particular structure, excellent electrical properties and high chemical stability, carbon nanotube and graphene based electrical devices have been widely developed for high performance label-free chemical/biological sensors. Here, we review the latest developments of carbon nanostructure-based transistor sensors in ultrasensitive detection of chemical/biological entities, such as poisonous gases, nucleic acids, proteins and cells.

  3. IN-LINE CHEMICAL SENSOR DEPLOYMENT IN A TRITIUM PLANT

    Energy Technology Data Exchange (ETDEWEB)

    Tovo, L.; Wright, J.; Torres, R.; Peters, B.

    2013-10-02

    The Savannah River Tritium Plant (TP) relies on well understood but aging sensor technology for process gas analysis. Though new sensor technologies have been brought to various readiness levels, the TP has been reluctant to install technologies that have not been tested in tritium service. This gap between sensor technology development and incorporating new technologies into practical applications demonstrates fundamental challenges that exist when transitioning from status quo to state-of-the-art in an extreme environment such as a tritium plant. These challenges stem from three root obstacles: 1) The need for a comprehensive assessment of process sensing needs and requirements; 2) The lack of a pick-list of process-compatible sensor technologies; and 3) The need to test technologies in a tritium-contaminated process environment without risking production. At Savannah River, these issues are being addressed in a two phase project. In the first phase, TP sensing requirements were determined by a team of process experts. Meanwhile, Savannah River National Laboratory sensor experts identified candidate technologies and related them to the TP processing requirements. The resulting roadmap links the candidate technologies to actual plant needs. To provide accurate assessments of how a candidate sensor technology would perform in a contaminated process environment, an instrument demonstration station was established within a TP glove box. This station was fabricated to TP process requirements and designed to handle high activity samples. The combination of roadmap and demonstration station provides the following assets: Creates a partnership between the process engineers and researchers for sensor selection, maturation, and insertion, Selects the right sensors for process conditions Provides a means for safely inserting new sensor technology into the process without risking production, and Provides a means to evaluate off normal occurrences where and when they occur

  4. X-Ray Photoelectron Spectroscopic Characterization of Chemically Modified Electrodes Used as Chemical Sensors and Biosensors: A Review

    Directory of Open Access Journals (Sweden)

    Elio Desimoni

    2015-04-01

    Full Text Available The characterization of chemically modified sensors and biosensors is commonly performed by cyclic voltammetry and electron microscopies, which allow verifying electrode mechanisms and surface morphologies. Among other techniques, X-ray photoelectron spectroscopy (XPS plays a unique role in giving access to qualitative, quantitative/semi-quantitative and speciation information concerning the sensor surface. Nevertheless, XPS remains rather underused in this field. The aim of this paper is to review selected articles which evidence the useful performances of XPS in characterizing the top surface layers of chemically modified sensors and biosensors. A concise introduction to X-ray Photoelectron Spectroscopy gives to the reader the essential background. The application of XPS for characterizing sensors suitable for food and environmental analysis is highlighted.

  5. Single walled carbon nanotubes with functionally adsorbed biopolymers for use as chemical sensors

    Science.gov (United States)

    Johnson, Jr., Alan T

    2013-12-17

    Chemical field effect sensors comprising nanotube field effect devices having biopolymers such as single stranded DNA or RNA functionally adsorbed to the nanotubes are provided. Also included are arrays comprising the sensors and methods of using the devices to detect volatile compounds.

  6. Piezoelectric microelectromechanical resonant sensors for chemical and biological detection.

    Science.gov (United States)

    Pang, Wei; Zhao, Hongyuan; Kim, Eun Sok; Zhang, Hao; Yu, Hongyu; Hu, Xiaotang

    2012-01-07

    Piezoelectric microelectromechanical systems (MEMS) resonant sensors, known for their excellent mass resolution, have been studied for many applications, including DNA hybridization, protein-ligand interactions, and immunosensor development. They have also been explored for detecting antigens, organic gas, toxic ions, and explosives. Most piezoelectric MEMS resonant sensors are acoustic sensors (with specific coating layers) that enable selective and label-free detection of biological events in real time. These label-free technologies have recently garnered significant attention for their sensitive and quantitative multi-parameter analysis of biological systems. Since piezoelectric MEMS resonant sensors do more than transform analyte mass or thickness into an electrical signal (e.g., frequency and impedance), special attention must be paid to their potential beyond microweighing, such as measuring elastic and viscous properties, and several types of sensors currently under development operate at different resonant modes (i.e., thickness extensional mode, thickness shear mode, lateral extensional mode, flexural mode, etc.). In this review, we provide an overview of recent developments in micromachined resonant sensors and activities relating to biochemical interfaces for acoustic sensors.

  7. Wide Dynamic Range CMOS Potentiostat for Amperometric Chemical Sensor

    OpenAIRE

    Wei-Song Wang; Wei-Ting Kuo; Hong-Yi Huang; Ching-Hsing Luo

    2010-01-01

    Presented is a single-ended potentiostat topology with a new interface connection between sensor electrodes and potentiostat circuit to avoid deviation of cell voltage and linearly convert the cell current into voltage signal. Additionally, due to the increased harmonic distortion quantity when detecting low-level sensor current, the performance of potentiostat linearity which causes the detectable current and dynamic range to be limited is relatively decreased. Thus, to alleviate these irreg...

  8. Direct-Dispense Polymeric Waveguides Platform for Optical Chemical Sensors

    Directory of Open Access Journals (Sweden)

    Mohamad Hajj-Hassan

    2008-12-01

    Full Text Available We describe an automated robotic technique called direct-dispense to fabricate a polymeric platform that supports optical sensor arrays. Direct-dispense, which is a type of the emerging direct-write microfabrication techniques, uses fugitive organic inks in combination with cross-linkable polymers to create microfluidic channels and other microstructures. Specifically, we describe an application of direct-dispensing to develop optical biochemical sensors by fabricating planar ridge waveguides that support sol-gelderived xerogel-based thin films. The xerogel-based sensor materials act as host media to house luminophore biochemical recognition elements. As a prototype implementation, we demonstrate gaseous oxygen (O2 responsive optical sensors that operate on the basis of monitoring luminescence intensity signals. The optical sensor employs a Light Emitting Diode (LED excitation source and a standard silicon photodiode as the detector. The sensor operates over the full scale (0%-100% of O2 concentrations with a response time of less than 1 second. This work has implications for the development of miniaturized multisensor platforms that can be cost-effectively and reliably mass-produced.

  9. Micro- and Nanostructured Metal Oxide Chemical Sensors for Volatile Organic Compounds

    Science.gov (United States)

    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.

  10. Morphology tailoring of nano/micro-structured conductive polymers, composites and their applications in chemical sensors.

    Science.gov (United States)

    Ma, Xingfa; Gao, Mingjun; He, Xiaochun; Li, Guang

    2010-11-01

    Conductive polymer is one of the important multi-functional materials. It has many applications in light-emitting diodes, chemical sensors, biosensors, et al. This paper provides a relatively comprehensive review on the progress of conductive polymer and composite as sensitive film for sensors to chemical vapors including patents, papers and our preliminary research results. Especially, the feature of conjugated polymers, the processing technology, doping characteristics and some factors affecting gas responses are discussed. Otherwise, the developments of nanostructured conductive polymer and organic-inorganic hybrid film sensor with high sensitivity and rapid response to vapors are also described, and some suggestions are proposed.

  11. On the sensitivity, selectivity, sensory information and optimal size of resistive chemical sensors

    CERN Document Server

    Kish, L B; Heszler, P; Smulko, J; Granqvist, Claes-Goran; Heszler, Peter; Kish, Laszlo B.; Smulko, Janusz

    2007-01-01

    Information theoretical tools are applied for the study of the sensitivity and selectivity enhancements of resistive fluctuation-enhanced sensors. General considerations are given for the upper limit of selectivity enhancement. The signal-to-noise ratio and information channel capacity of fluctuation-enhanced chemical sensors is compared to that of classical sensors providing a single output. The considerations are done at the generic level with a few concrete examples and include the estimation of scaling relations between the sensor size, the signal power, the noise power and the speed of measurements versus the size, sampling rate and measurement time.

  12. Chemical Kinetics, Heat Transfer, and Sensor Dynamics Revisited in a Simple Experiment

    Science.gov (United States)

    Sad, Maria E.; Sad, Mario R.; Castro, Alberto A.; Garetto, Teresita F.

    2008-01-01

    A simple experiment about thermal effects in chemical reactors is described, which can be used to illustrate chemical reactor models, the determination and validation of their parameters, and some simple principles of heat transfer and sensor dynamics. It is based in the exothermic reaction between aqueous solutions of sodium thiosulfate and…

  13. Integrated label-free silicon nanowire sensor arrays for (bio)chemical analysis

    NARCIS (Netherlands)

    De, Arpita; Nieuwkasteele, van Jan; Carlen, Edwin T.; Berg, van den Albert

    2013-01-01

    We present a label-free (bio)chemical analysis platform that uses all-electrical silicon nanowire sensor arrays integrated with a small volume microfluidic flow-cell for real-time (bio)chemical analysis and detection. The integrated sensing platform contains an automated multi-sample injection syste

  14. Sensory quality control of alcoholic beverages using fast chemical sensors

    OpenAIRE

    2010-01-01

    Control de calidad sensorial de bebidas alcohólicas utilizando rápidos sensores químicosEn la presente tesis Doctoral, han sido aplicados dos sensores artificiales para el análisis debebidas alcohólicas: la nariz electrónica basada en la espectrometría de masas (MS) y la lenguaelectrónica basada en la espectroscopía infrarroja con transformada de Fourier (FTIR). Elpropósito fue desarrollar nuevas estrategias para analizar la autenticidad de estos productos,desde un punto de vista sensorial, p...

  15. Fusing Sensor Paradigms to Acquire Chemical Information: An Integrative Role for Smart Biopolymeric Hydrogels.

    Science.gov (United States)

    Kim, Eunkyoung; Liu, Yi; Ben-Yoav, Hadar; Winkler, Thomas E; Yan, Kun; Shi, Xiaowen; Shen, Jana; Kelly, Deanna L; Ghodssi, Reza; Bentley, William E; Payne, Gregory F

    2016-10-01

    The Information Age transformed our lives but it has had surprisingly little impact on the way chemical information (e.g., from our biological world) is acquired, analyzed and communicated. Sensor systems are poised to change this situation by providing rapid access to chemical information. This access will be enabled by technological advances from various fields: biology enables the synthesis, design and discovery of molecular recognition elements as well as the generation of cell-based signal processors; physics and chemistry are providing nano-components that facilitate the transmission and transduction of signals rich with chemical information; microfabrication is yielding sensors capable of receiving these signals through various modalities; and signal processing analysis enhances the extraction of chemical information. The authors contend that integral to the development of functional sensor systems will be materials that (i) enable the integrative and hierarchical assembly of various sensing components (for chemical recognition and signal transduction) and (ii) facilitate meaningful communication across modalities. It is suggested that stimuli-responsive self-assembling biopolymers can perform such integrative functions, and redox provides modality-spanning communication capabilities. Recent progress toward the development of electrochemical sensors to manage schizophrenia is used to illustrate the opportunities and challenges for enlisting sensors for chemical information processing.

  16. Improved fiber-optic chemical sensor for penicillin

    Energy Technology Data Exchange (ETDEWEB)

    Healy, B.G.; Walt, D.R. [Tufts Univ., Medford, MA (United States)

    1995-12-15

    An optical penicillin biosensor is described, based on the enzyme penicillinase. The sensor is fabricated by selective photodeposition of analyte-sensitive polymer matrices on optical imaging fibers. The penicillin-sensitive matrices are fabricated by immobilizing the enzyme as micrometer-sized particles in a polymer hydrogel with a covalently bound pH indicator. An array of penicillin-sensitive and pH-sensitive matrices are fabricated on the same fiber. This array allows for the simultaneous, independent measurement of pH and penicillin. Independent measurement of the two analytes allows penicillin to be quantitated in the presence of a concurrent pH change. An analysis was conducted of enzyme kinetic parameters in order to model the penicillin response of the sensor at all pH values. This analysis accounts for the varying activity of the immobilized penicillinase at different pH values. The sensor detects penicillin in the range 0.25-10.0 mM in the pH range 6.2-7.5. The sensor was used to quantify penicillin concentration produced during a Penicillium chrysogenum fermentation. 27 refs., 7 figs., 1 tab.

  17. Development of new sensors for detection of organic chemicals

    DEFF Research Database (Denmark)

    Bache, Michael

    koncentrationer af kemikalier. En cantilever baseret overflade stress sensor er undersøgt som en mulig metode til påvisning af 2,6-dichlorbenzamid (BAM) pesticidrester i vand. Cantilever overflade stress princip blev undersøgt ved hjælp af piezo resistiv system fra Cantion/Nanonord A/S, og en optisk laser...

  18. Dynamic 3-D chemical agent cloud mapping using a sensor constellation deployed on mobile platforms

    Science.gov (United States)

    Cosofret, Bogdan R.; Konno, Daisei; Rossi, David; Marinelli, William J.; Seem, Pete

    2014-05-01

    The need for standoff detection technology to provide early Chem-Bio (CB) threat warning is well documented. Much of the information obtained by a single passive sensor is limited to bearing and angular extent of the threat cloud. In order to obtain absolute geo-location, range to threat, 3-D extent and detailed composition of the chemical threat, fusion of information from multiple passive sensors is needed. A capability that provides on-the-move chemical cloud characterization is key to the development of real-time Battlespace Awareness. We have developed, implemented and tested algorithms and hardware to perform the fusion of information obtained from two mobile LWIR passive hyperspectral sensors. The implementation of the capability is driven by current Nuclear, Biological and Chemical Reconnaissance Vehicle operational tactics and represents a mission focused alternative of the already demonstrated 5-sensor static Range Test Validation System (RTVS).1 The new capability consists of hardware for sensor pointing and attitude information which is made available for streaming and aggregation as part of the data fusion process for threat characterization. Cloud information is generated using 2-sensor data ingested into a suite of triangulation and tomographic reconstruction algorithms. The approaches are amenable to using a limited number of viewing projections and unfavorable sensor geometries resulting from mobile operation. In this paper we describe the system architecture and present an analysis of results obtained during the initial testing of the system at Dugway Proving Ground during BioWeek 2013.

  19. Development of Fabric-Based Chemical Gas Sensors for Use as Wearable Electronic Noses

    Directory of Open Access Journals (Sweden)

    Thara Seesaard

    2015-01-01

    Full Text Available Novel gas sensors embroidered into fabric substrates based on polymers/ SWNT-COOH nanocomposites were proposed in this paper, aiming for their use as a wearable electronic nose (e-nose. The fabric-based chemical gas sensors were fabricated by two main processes: drop coating and embroidery. Four potential polymers (PVC, cumene-PSMA, PSE and PVP/functionalized-SWCNT sensing materials were deposited onto interdigitated electrodes previously prepared by embroidering conductive thread on a fabric substrate to make an optimal set of sensors. After preliminary trials of the obtained sensors, it was found that the sensors yielded a electrical resistance in the region of a few kilo-Ohms. The sensors were tested with various volatile compounds such as ammonium hydroxide, ethanol, pyridine, triethylamine, methanol and acetone, which are commonly found in the wastes released from the human body. These sensors were used to detect and discriminate between the body odors of different regions and exist in various forms such as the urine, armpit and exhaled breath odor. Based on a simple pattern recognition technique, we have shown that the proposed fabric-based chemical gas sensors can discriminate the human body odor from two persons.

  20. Time-resolved fluorescence spectroscopy for chemical sensors

    Science.gov (United States)

    Draxler, Sonja; Lippitsch, Max E.

    1996-07-01

    A family of sensors is presented with fluorescence decay-time measurements used as the sensing technique. The concept is to take a single fluorophore with a suitably long fluorescence decay time as the basic building block for numerous different sensors. Analyte recognition can be performed by different functional groups that are necessary for selective interaction with the analyte. To achieve this, the principle of excited-state electron transfer is applied with pyrene as the fluorophore. Therefore the same instrumentation based on a small, ambient air-nitrogen laser and solid-state electronics can be used to measure different analytes, for example, oxygen, pH, carbon dioxide, potassium, ammonium, lead, cadmium, zinc, and phosphate.

  1. Wide Dynamic Range CMOS Potentiostat for Amperometric Chemical Sensor

    Directory of Open Access Journals (Sweden)

    Wei-Song Wang

    2010-03-01

    Full Text Available Presented is a single-ended potentiostat topology with a new interface connection between sensor electrodes and potentiostat circuit to avoid deviation of cell voltage and linearly convert the cell current into voltage signal. Additionally, due to the increased harmonic distortion quantity when detecting low-level sensor current, the performance of potentiostat linearity which causes the detectable current and dynamic range to be limited is relatively decreased. Thus, to alleviate these irregularities, a fully-differential potentiostat is designed with a wide output voltage swing compared to single-ended potentiostat. Two proposed potentiostats were implemented using TSMC 0.18-μm CMOS process for biomedical application. Measurement results show that the fully differential potentiostat performs relatively better in terms of linearity when measuring current from 500 ºpA to 10 uA. Besides, the dynamic range value can reach a value of 86 dB.

  2. SPE Membrane Electrode and Its Application to Chemical Sensor

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The structure and proton conducting mechanism of solid polymer electrolyte (SPE) are described. Since the conductivity of electrolyte is important in SPE electrochemical cell research and development, we investigate quantitatively the conductivity of Nafion membrane and its dependence on temperature and relative humidity. Ex perimental results show that the conductivity of Nafion membrane increases with temperature and relative humidity. We also reports on the preparation and development of SPE membrane electrode with the emphasis on the mix ture pressing method and impregnation-reduction process to prepare SPE composite electrode assemblies and their application to electrochemical sensors. We also investigate and fabricate a potentiometric electrochemical sensor of hydrogen and ethylene to measure the hydrogen and ethylene partial pressure.

  3. Chemical Sensors Based on Molecularly Imprinted Sol-Gel Materials

    OpenAIRE

    Dickert, Franz L.; Lieberzeit, Peter A.; Adnan Mujahid

    2010-01-01

    The sol-gel technique is earning the worldwide attention of researchers in the field of material science, due to its versatility in synthesizing inorganic ceramic materials at mild conditions. High purity, homogeneity, controlled porosity, stable temperature and nanoscale structuring are the most remarkable features offered by this method for generating highly sensitive and selective matrices to incorporate analyte molecules. The crafting of sol-gel sensors through molecular imprinting has pu...

  4. Fault Diagnosis Based on Chemical Sensor Data with an Active Deep Neural Network.

    Science.gov (United States)

    Jiang, Peng; Hu, Zhixin; Liu, Jun; Yu, Shanen; Wu, Feng

    2016-10-13

    Big sensor data provide significant potential for chemical fault diagnosis, which involves the baseline values of security, stability and reliability in chemical processes. A deep neural network (DNN) with novel active learning for inducing chemical fault diagnosis is presented in this study. It is a method using large amount of chemical sensor data, which is a combination of deep learning and active learning criterion to target the difficulty of consecutive fault diagnosis. DNN with deep architectures, instead of shallow ones, could be developed through deep learning to learn a suitable feature representation from raw sensor data in an unsupervised manner using stacked denoising auto-encoder (SDAE) and work through a layer-by-layer successive learning process. The features are added to the top Softmax regression layer to construct the discriminative fault characteristics for diagnosis in a supervised manner. Considering the expensive and time consuming labeling of sensor data in chemical applications, in contrast to the available methods, we employ a novel active learning criterion for the particularity of chemical processes, which is a combination of Best vs. Second Best criterion (BvSB) and a Lowest False Positive criterion (LFP), for further fine-tuning of diagnosis model in an active manner rather than passive manner. That is, we allow models to rank the most informative sensor data to be labeled for updating the DNN parameters during the interaction phase. The effectiveness of the proposed method is validated in two well-known industrial datasets. Results indicate that the proposed method can obtain superior diagnosis accuracy and provide significant performance improvement in accuracy and false positive rate with less labeled chemical sensor data by further active learning compared with existing methods.

  5. Fault Diagnosis Based on Chemical Sensor Data with an Active Deep Neural Network

    Directory of Open Access Journals (Sweden)

    Peng Jiang

    2016-10-01

    Full Text Available Big sensor data provide significant potential for chemical fault diagnosis, which involves the baseline values of security, stability and reliability in chemical processes. A deep neural network (DNN with novel active learning for inducing chemical fault diagnosis is presented in this study. It is a method using large amount of chemical sensor data, which is a combination of deep learning and active learning criterion to target the difficulty of consecutive fault diagnosis. DNN with deep architectures, instead of shallow ones, could be developed through deep learning to learn a suitable feature representation from raw sensor data in an unsupervised manner using stacked denoising auto-encoder (SDAE and work through a layer-by-layer successive learning process. The features are added to the top Softmax regression layer to construct the discriminative fault characteristics for diagnosis in a supervised manner. Considering the expensive and time consuming labeling of sensor data in chemical applications, in contrast to the available methods, we employ a novel active learning criterion for the particularity of chemical processes, which is a combination of Best vs. Second Best criterion (BvSB and a Lowest False Positive criterion (LFP, for further fine-tuning of diagnosis model in an active manner rather than passive manner. That is, we allow models to rank the most informative sensor data to be labeled for updating the DNN parameters during the interaction phase. The effectiveness of the proposed method is validated in two well-known industrial datasets. Results indicate that the proposed method can obtain superior diagnosis accuracy and provide significant performance improvement in accuracy and false positive rate with less labeled chemical sensor data by further active learning compared with existing methods.

  6. Multi-Sensor Integration to Map Odor Distribution for the Detection of Chemical Sources

    Directory of Open Access Journals (Sweden)

    Xiang Gao

    2016-07-01

    Full Text Available This paper addresses the problem of mapping odor distribution derived from a chemical source using multi-sensor integration and reasoning system design. Odor localization is the problem of finding the source of an odor or other volatile chemical. Most localization methods require a mobile vehicle to follow an odor plume along its entire path, which is time consuming and may be especially difficult in a cluttered environment. To solve both of the above challenges, this paper proposes a novel algorithm that combines data from odor and anemometer sensors, and combine sensors’ data at different positions. Initially, a multi-sensor integration method, together with the path of airflow was used to map the pattern of odor particle movement. Then, more sensors are introduced at specific regions to determine the probable location of the odor source. Finally, the results of odor source location simulation and a real experiment are presented.

  7. Recent Development in Optical Chemical Sensors Coupling with Flow Injection Analysis

    Directory of Open Access Journals (Sweden)

    Fuensanta Sánchez Rojas

    2006-10-01

    Full Text Available Optical techniques for chemical analysis are well established and sensors based on thesetechniques are now attracting considerable attention because of their importance in applications suchas environmental monitoring, biomedical sensing, and industrial process control. On the other hand,flow injection analysis (FIA is advisable for the rapid analysis of microliter volume samples and canbe interfaced directly to the chemical process. The FIA has become a widespread automatic analyticalmethod for more reasons; mainly due to the simplicity and low cost of the setups, their versatility, andease of assembling. In this paper, an overview of flow injection determinations by using opticalchemical sensors is provided, and instrumentation, sensor design, and applications are discussed. Thiswork summarizes the most relevant manuscripts from 1980 to date referred to analysis using opticalchemical sensors in FIA.

  8. A Novel Wearable Electronic Nose for Healthcare Based on Flexible Printed Chemical Sensor Array

    Directory of Open Access Journals (Sweden)

    Panida Lorwongtragool

    2014-10-01

    Full Text Available A novel wearable electronic nose for armpit odor analysis is proposed by using a low-cost chemical sensor array integrated in a ZigBee wireless communication system. We report the development of a carbon nanotubes (CNTs/polymer sensor array based on inkjet printing technology. With this technique both composite-like layer and actual composite film of CNTs/polymer were prepared as sensing layers for the chemical sensor array. The sensor array can response to a variety of complex odors and is installed in a prototype of wearable e-nose for monitoring the axillary odor released from human body. The wearable e-nose allows the classification of different armpit odors and the amount of the volatiles released as a function of level of skin hygiene upon different activities.

  9. A Novel Wearable Electronic Nose for Healthcare Based on Flexible Printed Chemical Sensor Array

    Science.gov (United States)

    Lorwongtragool, Panida; Sowade, Enrico; Watthanawisuth, Natthapol; Baumann, Reinhard R.; Kerdcharoen, Teerakiat

    2014-01-01

    A novel wearable electronic nose for armpit odor analysis is proposed by using a low-cost chemical sensor array integrated in a ZigBee wireless communication system. We report the development of a carbon nanotubes (CNTs)/polymer sensor array based on inkjet printing technology. With this technique both composite-like layer and actual composite film of CNTs/polymer were prepared as sensing layers for the chemical sensor array. The sensor array can response to a variety of complex odors and is installed in a prototype of wearable e-nose for monitoring the axillary odor released from human body. The wearable e-nose allows the classification of different armpit odors and the amount of the volatiles released as a function of level of skin hygiene upon different activities. PMID:25340447

  10. New Hydrodynamic Electrochemical Arrangement for Cadmium Ions Detection Using Thick-Film Chemical Sensor Electrodes

    Directory of Open Access Journals (Sweden)

    Rene Kizek

    2006-11-01

    Full Text Available Miniaturization and integration of chemical devices into modules that aredimensionally comparable with electronic chips (Lab on Chip is nowadays developingworldwide. The aim of our work was to suggest and optimize the best conditions forfabrication of TFT sensor due to its sensitivity and low experimental deviations. Newelectrochemical analytical device was developed to ensure certain known mass transport toelectrodes, which is the most limiting process that influencing the response quality of thesensor. The device consists from rotating conic vessel for measured sample and stick-inthick-film sensor. The sensors responses were tested under trace analysis of cadmium.Measurements were done also with the others electrochemical arrangements to comparewith the new one. The sensor output current response dependence on the liquid velocity andgeometrical arrangement within using standard electrochemical couple of potassiumferrocyanide-ferricyanide is presented. We found out that the new device with controlledflow of electrolyte to sensor worked properly and gave satisfactory results.

  11. A NEW BIOGENIC SULFIDE CHEMICAL SENSOR FOR MARINE ENVIRONMENTAL MONITORING AND SURVEY

    Institute of Scientific and Technical Information of China (English)

    宋金明; 赵卫东

    2001-01-01

    A new convenient sulfide electrochemical sensor for marine environmental insitumonitoring and real time survey was developed. The new sensor based on a solid Ag2 S membrane electrode has outstanding chemical sensitivity and stability. It responds to the activity of sulfide ions according to a Nernsfian slope of - 31mV/decade. The sensor can be used to determine the total concentration of sulfides ( CT ) by calibrating the pH value of the solution to a standard pH. The practical measurement range for total sulfide concentration is 0.1 - 10 mg/L in seawater. The sensor has a very low potential drift ( < 4mV) during two months in 0.1 mg/L sulfide seawater. This paper describes the preparation of the sensitive membrane and some main properties of the sensor.

  12. A NEW BIOGENIC SULFIDE CHEMICAL SENSOR FOR MARINE ENVIRONMENTAL MONITORING AND SURVEY

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new convenient sulfide electrochemical sensor for marine environmental in-situ monitoring and real time survey was developed. The new sensor based on a solid Ag2S membrane electrode has outstanding chemical sensitivity and stability. It responds to the activity of sulfide ions according to a Nernstian slope of -31mV/decade. The sensor can be used to determine the total concentration of sulfides (CT) by calibrating the pH value of the solution to a standard pH. The practical measurement range for total sulfide concentration is 0.1-10 mg/L in seawater. The sensor has a very low potential drift (<4mV) during two months in 0.1 mg/L sulfide seawater. This paper describes the preparation of the sensitive membrane and some main properties of the sensor.

  13. Evaluation of chemical sensors for in situ ground-water monitoring at the Hanford Site

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, E.M.; Hostetler, D.D.

    1989-03-01

    This report documents a preliminary review and evaluation of instrument systems and sensors that may be used to detect ground-water contaminants in situ at the Hanford Site. Three topics are covered in this report: (1) identification of a group of priority contaminants at Hanford that could be monitored in situ, (2) a review of current instrument systems and sensors for environmental monitoring, and (3) an evaluation of instrument systems that could be used to monitor Hanford contaminants. Thirteen priority contaminants were identified in Hanford ground water, including carbon tetrachloride and six related chlorinated hydrocarbons, cyanide, methyl ethyl ketone, chromium (VI), fluoride, nitrate, and uranium. Based on transduction principles, chemical sensors were divided into four classes, ten specific types of instrument systems were considered: fluorescence spectroscopy, surface-enhanced Raman spectroscopy (SERS), spark excitation-fiber optic spectrochemical emission sensor (FOSES), chemical optrodes, stripping voltammetry, catalytic surface-modified ion electrode immunoassay sensors, resistance/capacitance, quartz piezobalance and surface acoustic wave devices. Because the flow of heat is difficult to control, there are currently no environmental chemical sensors based on thermal transduction. The ability of these ten instrument systems to detect the thirteen priority contaminants at the Hanford Site at the required sensitivity was evaluated. In addition, all ten instrument systems were qualitatively evaluated for general selectivity, response time, reliability, and field operability. 45 refs., 23 figs., 7 tabs.

  14. Temperature-Insensitive Chemical Sensor with Twin Bragg Gratings in an Optical Fibre

    Institute of Scientific and Technical Information of China (English)

    SANG Xin-Zhu; YU Chong-Xiu; YAN Bin-Bin; MA Jian-Xin; MENG Zhao-Fang; Mayteevarunyoo T.; LU Nai-Guang

    2006-01-01

    To reduce temperature sensitivity of the fibre Bragg grating (FBG) chemical sensor, a simple method is proposed by measuring the peak wavelength difference between an etched FBG and an un-etched one in an optical fibre.Thermal characteristics and chemical sensitivity of the sensor are experimentally investigated. The experimental results indicate that the etched FBG and the rest one have almost the same thermal response, and concentration changes of the surrounding chemical solutions can be detected by measuring the peak wavelength difference between them. The sensor has been used to measure the concentrations of propylene glycol solutions and sugar solutions, and it could detect 0.7% and 0.45% concentration changes for them with an optical spectrum analyser in resolution of 10pm.

  15. Chemically responsive nanoporous pigments: colorimetric sensor arrays and the identification of aliphatic amines.

    Science.gov (United States)

    Bang, Jin Ho; Lim, Sung H; Park, Erwin; Suslick, Kenneth S

    2008-11-18

    A general method has been developed for the preparation of microspheres of nanoporous pigments, their formulation into chemically responsive pigment inks, and the printing of these inks as colorimetric sensor arrays. Using an ultrasonic-spray aerosol-gel synthesis from chemically responsive dyes and common silica precursors, 16 different nanoporous pigment microspheres have been prepared and characterized. New colorimetric sensor arrays have been created by printing inks of these chemically responsive pigments as primary sensor elements; these arrays have been successfully tested for the detection, identification, and quantitation of toxic aliphatic amines. Among 11 structurally similar amines, complete identification of each analyte without confusion was achieved using hierarchical cluster analysis (HCA). Furthermore, visual identification of ammonia gas was easily made at the IDLH (immediately dangerous to life or health), PEL (permissible exposure limits), and 0.1 PEL concentrations with high reproducibility.

  16. Different sensing mechanisms in single wire and mat carbon nanotubes chemical sensors

    CERN Document Server

    Neumann, P L; Dobrik, G; Kertész, K; Horváth, E; Lukács, I E; Biró, L P; Horváth, Z E

    2014-01-01

    Chemical sensing properties of single wire and mat form sensor structures fabricated from the same carbon nanotube (CNT) materials have been compared. Sensing properties of CNT sensors were evaluated upon electrical response in the presence of five vapours as acetone, acetic acid, ethanol, toluene, and water. Diverse behaviour of single wire CNT sensors was found, while the mat structures showed similar response for all the applied vapours. This indicates that the sensing mechanism of random CNT networks cannot be interpreted as a simple summation of the constituting individual CNT effects, but is associated to another robust phenomenon, localized presumably at CNT-CNT junctions, must be supposed.

  17. New Potentiometric Wireless Chloride Sensors Provide High Resolution Information on Chemical Transport Processes in Streams

    Science.gov (United States)

    Smettem, Keith; Harris, Nick; Cranny, Andy; Klaus, Julian; Pfister, Laurent

    2016-04-01

    Quantifying the travel times, pathways and dispersion of solutes moving through stream environments is critical for understanding the biogeochemical cycling processes that control ecosystem functioning. Validation of stream solute transport and exchange process models requires data obtained from in-stream measurement of chemical concentration changes through time. This can be expensive and time consuming, leading to a need for cheap distributed sensor arrays that respond instantly and record chemical transport at points of interest on timescales of seconds. To meet this need we apply new, low-cost (in the order of a euro per sensor) potentiometric chloride sensors used in a distributed array to obtain data with high spatial and temporal resolution. The application here is to monitoring in-stream hydrodynamic transport and dispersive mixing of an injected chemical, in this case NaCl. We present data obtained from the distributed sensor array under baseflow conditions for three stream reaches in Luxembourg. Sensor results are comparable to data obtained from more expensive electrical conductivity meters and allow spatial resolution of hydrodynamic mixing processes and identification of chemical 'dead zones' in the study reaches.

  18. MEMS Cantilever Sensor for THz Photoacoustic Chemical Sensing and Spectroscopy

    Science.gov (United States)

    2013-12-26

    niobate (LiNbO3), sodium potassium niobate ((K,Na)NbO3), and polyvinylidene fluoride (PVDF). Lead zirconate titanate, commonly referred to as PZT is...The sensor used was a mirrored 25 µm thick Mylar droplet shaped pellicle cantilever which was 13 mm long, 2.5 mm wide at the tip, with a narrower...C2H2) mixture in a helium dilution [84]. The cantilever used was 1 μm thick, 500 μm long, and 100 μm wide, which was positioned over a 1.5 mm

  19. Coagulation sensors based on magnetostrictive delay lines for biomedical and chemical engineering applications

    Energy Technology Data Exchange (ETDEWEB)

    Maliaritsi, E. [Laboratory of Physical Metallurgy, School of Mining and Metallurgy Engineering, National Technical University of Athens, Zografou Campus, Athens 15780 (Greece); Zoumpoulakis, L. [Laboratory of Materials Science and Technology, Inter-disciplinary Postgraduate Programme of NTUA, School of Chemical Engineering, National Technical University of Athens, Zografou Campus, 157 73 Athens (Greece); Simitzis, J. [Laboratory of Materials Science and Technology, Inter-disciplinary Postgraduate Programme of NTUA, School of Chemical Engineering, National Technical University of Athens, Zografou Campus, 157 73 Athens (Greece); Vassiliou, P. [Iaso General Hospital, Athens (Greece); Hristoforou, E. [Laboratory of Physical Metallurgy, School of Mining and Metallurgy Engineering, National Technical University of Athens, Zografou Campus, Athens 15780 (Greece)]. E-mail: eh@metal.ntua.gr

    2006-04-15

    Coagulation sensors based on the magnetostrictive delay line technique are presented in this paper. They are based on magnetostrictive ribbons and are used for measuring the coagulation, curing or solidification time of different liquids. Experimental results indicate that the presented sensing elements can determine the blood coagulation with remarkable repeatability, thus allowing their use as blood coagulation sensors. Additionally, results indicate that they can also measure curing time of resins, solidification of fluids and coagulation of chemical substances, therefore allowing their implementation in chemical engineering applications.

  20. Detection of Landmine Signature using SAW-based Polymer-coated Chemical Sensor

    Directory of Open Access Journals (Sweden)

    O. K. Kannan

    2004-07-01

    Full Text Available The explosive charge within a landmine is the source for a mixture of chemical vapours that form a distinctive chemical signature indicative of a landmine. The concentrations of these compounds in the air over landmines is extremely low (parts-per-trillion or lower, well below the minimum detection limits of most field-portable chemical sensors. This paper describes a portable  surface acoustic wave-based polymer-coated sensor for the detection of hidden explosives. The sensitivity and selectivity of polymer-based sensors depend on several factors including the chemo-selective coating used, the physical properties of the vapour(s of interest, the selected transducers, and the operating conditions. The polymer-based sensor was calibrated in the  laboratory using the explosive vapour generator. The preliminary results indicated that the carbowax 1000 could be a very good chemical interface to sense low levels of chemical signature of explosive material. Response for 50 ppb of TNT vapours was observed to be 400 Hz for an exposure of 2 min.

  1. Ultra-Trace Chemical Sensing with Long-Wave Infrared Cavity-Enhanced Spectroscopic Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Taubman, Matthew S.; Myers, Tanya L.; Cannon, Bret D.; Williams, Richard M.; Schultz, John F.

    2003-02-20

    The infrared sensors task of Pacific Northwest National Laboratory's (PNNL's) Remote Spectroscopy Project (Task B of Project PL211) is focused on the science and technology of remote and in-situ spectroscopic chemical sensors for detecting proliferation and coun-tering terrorism. Missions to be addressed by remote chemical sensor development in-clude detecting proliferation of nuclear or chemical weapons, and providing warning of terrorist use of chemical weapons. Missions to be addressed by in-situ chemical sensor development include countering terrorism by screening luggage, personnel, and shipping containers for explosives, firearms, narcotics, chemical weapons, or chemical weapons residues, and mapping contaminated areas. The science and technology is also relevant to chemical weapons defense, air operations support, monitoring emissions from chemi-cal weapons destruction or industrial activities, law enforcement, medical diagnostics, and other applications. Sensors for most of these missions will require extreme chemical sensitivity and selectiv-ity because the signature chemicals of importance are expected to be present in low con-centrations or have low vapor pressures, and the ambient air is likely to contain pollutants or other chemicals with interfering spectra. Cavity-enhanced chemical sensors (CES) that draw air samples into optical cavities for laser-based interrogation of their chemical content promise real-time, in-situ chemical detection with extreme sensitivity to specified target molecules and superb immunity to spectral interference and other sources of noise. PNNL is developing CES based on quantum cascade (QC) lasers that operate in the mid-wave infrared (MWIR - 3 to 5 microns) and long-wave infrared (LWIR - 8 to 14 mi-crons), and CES based on telecommunications lasers operating in the short-wave infrared (SWIR - 1 to 2 microns). All three spectral regions are promising because smaller mo-lecular absorption cross sections in the SWIR

  2. Paper-based chemical and biological sensors: Engineering aspects.

    Science.gov (United States)

    Ahmed, Snober; Bui, Minh-Phuong Ngoc; Abbas, Abdennour

    2016-03-15

    Remarkable efforts have been dedicated to paper-based chemosensors and biosensors over the last few years, mainly driven by the promise of reaching the best trade-off between performance, affordability and simplicity. Because of the low-cost and rapid prototyping of these sensors, recent research has been focused on providing affordable diagnostic devices to the developing world. The recent progress in sensitivity, multi-functionality and integration of microfluidic paper-based analytical devices (µPADs), increasingly suggests that this technology is not only attractive in resource-limited environments but it also represents a serious challenger to silicon, glass and polymer-based biosensors. This review discusses the design, chemistry and engineering aspects of these developments, with a focus on the past few years.

  3. Online Decorrelation of Humidity and Temperature in Chemical Sensors for Continuous Monitoring

    CERN Document Server

    Huerta, Ramon; Fonollosa, Jordi; Rulkov, Nikolai F; Rodriguez-Lujan, Irene

    2016-01-01

    A method for online decorrelation of chemical sensor readings from the effects of environmental humidity and temperature variations is proposed. The goal is to improve the accuracy of electronic nose measurements for continuous monitoring by processing data from simultaneous readings of environmental humidity and temperature. The electronic nose setup built for this study included eight different metal-oxide sensors, temperature and humidity sensors with a wireless communication link to PC. This wireless electronic nose was used to monitor air for two years in the residence of one of the authors and collected data continuously during 510 full days with a sampling rate of 2 samples per second. To estimate the effects of variations in air humidity and temperature on the chemical sensors readings, we used a standard energy band model for an n-type metal-oxide sensor. The main assumption of the model is that variations in sensor conductivity can be expressed as a nonlinear function of changes in the semiconductor...

  4. Complementary Split-Ring Resonator-Loaded Microfluidic Ethanol Chemical Sensor

    Directory of Open Access Journals (Sweden)

    Ahmed Salim

    2016-10-01

    Full Text Available In this paper, a complementary split-ring resonator (CSRR-loaded patch is proposed as a microfluidic ethanol chemical sensor. The primary objective of this chemical sensor is to detect ethanol’s concentration. First, two tightly coupled concentric CSRRs loaded on a patch are realized on a Rogers RT/Duroid 5870 substrate, and then a microfluidic channel engraved on polydimethylsiloxane (PDMS is integrated for ethanol chemical sensor applications. The resonant frequency of the structure before loading the microfluidic channel is 4.72 GHz. After loading the microfluidic channel, the 550 MHz shift in the resonant frequency is ascribed to the dielectric perturbation phenomenon when the ethanol concentration is varied from 0% to 100%. In order to assess the sensitivity range of our proposed sensor, various concentrations of ethanol are tested and analyzed. Our proposed sensor exhibits repeatability and successfully detects 10% ethanol as verified by the measurement set-up. It has created headway to a miniaturized, non-contact, low-cost, reliable, reusable, and easily fabricated design using extremely small liquid volumes.

  5. B36 borophene as an electronic sensor for formaldehyde: Quantum chemical analysis

    Science.gov (United States)

    Shahbazi Kootenaei, Amirhossein; Ansari, Goodarz

    2016-08-01

    Pristine carbon nanotubes and graphene show great sensitivity toward several lethal gases but cannot identify some extremely toxic chemicals such as formaldehyde (HCOH). Recent successful synthesis of all-boron graphene-like sheets attracted strong interest in exploring their possible applications. Herein, we inspected the potential application of B36 borophene sheet as a sensor for HCOH detection, using density functional theory computations. Different theoretical levels including B97D and Minnesota 06 functionals with different basis sets were employed. It was predicted that the electrical conductivity of B36 borophene significantly increases at the presence of HCOH molecules, thereby generating an electrical signal. The electrical signal is increased by increasing the number of adsorbed HCOH molecules, indicating that this sensor is sensitive to the concentration (or pressure) of HCOH gas. These results suggest that the pristine borophene may be used in the HCOH chemical sensors.

  6. Integrated label-free silicon nanowire sensor arrays for (bio)chemical analysis.

    Science.gov (United States)

    De, Arpita; van Nieuwkasteele, Jan; Carlen, Edwin T; van den Berg, Albert

    2013-06-07

    We present a label-free (bio)chemical analysis platform that uses all-electrical silicon nanowire sensor arrays integrated with a small volume microfluidic flow-cell for real-time (bio)chemical analysis and detection. The integrated sensing platform contains an automated multi-sample injection system that eliminates erroneous sensor responses from sample switching due to flow rate fluctuations and provides precise sample volumes down to 10 nl. Biochemical sensing is demonstrated with real-time 15-mer DNA-PNA (peptide nucleic acid) duplex hybridization measurements from different sample concentrations in a low ionic strength, and the equilibrium dissociation constant KD ≈ 140 nM has been extracted from the experimental data using the first order Langmuir binding model. Chemical sensing is demonstrated with pH measurements from different injected samples in flow that have sensitivities consistent with the gate-oxide materials. A differential sensor measurement configuration results in a 30× reduction in sensor drift. The integrated label-free analysis platform is suitable for a wide range of small volume chemical and biochemical analyses.

  7. Highly sensitive surface plasmon resonance chemical sensor based on Goos-Hanchen effects

    Science.gov (United States)

    Yin, Xiaobo; Hesselink, Lambertus

    2006-08-01

    The resonance enhanced Goos-Hanchen shifts at attenuated total internal reflection enables the possibility for highly sensitive surface plasmon resonance sensor. The observed giant displacements result from the singular phase retardation at the resonance where the phase is continuous but changes dramatically. The phenomenon is proposed for chemical sensing and the superior sensitivity is demonstrated.

  8. Development of High Temperature/High Sensitivity Novel Chemical Resistive Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chonglin; Nash, Patrick; Ma, Chunrui; Enriquez, Erik; Wang, Haibing; Xu, Xing; Bao, Shangyong; Collins, Gregory

    2013-08-13

    The research has been focused to design, fabricate, and develop high temperature/high sensitivity novel multifunctional chemical sensors for the selective detection of fossil energy gases used in power and fuel systems. By systematically studying the physical properties of the LnBaCo{sub 2}O{sub 5+d} (LBCO) [Ln=Pr or La] thin-films, a new concept chemical sensor based high temperature chemical resistant change has been developed for the application for the next generation highly efficient and near zero emission power generation technologies. We also discovered that the superfast chemical dynamic behavior and an ultrafast surface exchange kinetics in the highly epitaxial LBCO thin films. Furthermore, our research indicates that hydrogen can superfast diffuse in the ordered oxygen vacancy structures in the highly epitaxial LBCO thin films, which suggest that the LBCO thin film not only can be an excellent candidate for the fabrication of high temperature ultra sensitive chemical sensors and control systems for power and fuel monitoring systems, but also can be an excellent candidate for the low temperature solid oxide fuel cell anode and cathode materials.

  9. Silicon chip integrated photonic sensors for biological and chemical sensing

    Science.gov (United States)

    Chakravarty, Swapnajit; Zou, Yi; Yan, Hai; Tang, Naimei; Chen, Ray T.

    2016-03-01

    We experimentally demonstrate applications of photonic crystal waveguide based devices for on-chip optical absorption spectroscopy for the detection of chemical warfare simulant, triethylphosphate as well as applications with photonic crystal microcavity devices in the detection of biomarkers for pancreatic cancer in patient serum and cadmium metal ions in heavy metal pollution sensing. At mid-infrared wavelengths, we experimentally demonstrate the higher sensitivity of photonic crystal based structures compared to other nanophotonic devices such as strip and slot waveguides with detection down to 10ppm triethylphosphate. We also detected 5ppb (parts per billion) of cadmium metal ions in water at near-infrared wavelengths using established techniques for the detection of specific probe-target biomarker conjugation chemistries.

  10. Development of a Wireless and Passive SAW-Based Chemical Sensor for Organophosphorous Compound Detection

    Directory of Open Access Journals (Sweden)

    Fang-Qian Xu

    2015-12-01

    Full Text Available A new wireless and passive surface acoustic wave (SAW-based chemical sensor for organophosphorous compound (OC detection is presented. A 434 MHz reflective delay line configuration composed by single phase unidirectional transducers (SPUDTs and three shorted reflectors was fabricated on YZ LiNbO3 piezoelectric substrate as the sensor element. A thin fluoroalcoholpolysiloxane (SXFA film acted as the sensitive interface deposited onto the SAW propagation path between the second and last reflectors of the SAW device. The first reflector was used for the temperature compensation utilizing the difference method. The adsorption between the SXFA and OC molecules modulates the SAW propagation, especially for the time delay of the SAW, hence, the phase shifts of the reflection peaks from the corresponding reflectors can be used to characterize the target OC. Prior to the sensor fabrication, the coupling of modes (COM and perturbation theory were utilized to predict the SAW device performance and the gas adsorption. Referring to a frequency-modulated continuous wave (FMCW-based reader unit, the developed SAW chemical sensor was wirelessly characterized in gas exposure experiments for dimethylmethylphosphonate (DMMP detection. Sensor performance parameters such as phase sensitivity, repeatability, linearity, and temperature compensation were evaluated experimentally.

  11. Miniaturized, biopsy-implantable chemical sensor with wireless, magnetic resonance readout.

    Science.gov (United States)

    Vassiliou, C C; Liu, V H; Cima, M J

    2015-09-07

    Biopsy is an important diagnostic tool for a broad range of conditions. Cancer diagnoses, for example, are confirmed using tissue explanted with biopsy. Here we demonstrate a miniaturized wireless sensor that can be implanted during a biopsy procedure and return chemical information from within the body. Power and readout are wireless via weak magnetic resonant coupling to an external reader. The sensor is filled with responsive nuclear magnetic resonance (NMR) contrast agents for chemical sensitivity, and on-board circuitry constrains the NMR measurement to the contents. This sensor enables longitudinal monitoring of the same location, and its simple readout mechanism is ideal for applications not requiring the spatial information available through imaging techniques. We demonstrated the operation of this sensor by measuring two metabolic markers, both in vitro and in vivo: pH in flowing fluid for over 25 days and in a xenograft tumor model in mice, and oxygen in flowing gas and in a rat hind-limb constriction experiment. The results suggest that this in vivo sensing platform is generalizable to other available NMR contrast agents. These sensors have potential for use in biomedicine, environmental monitoring and quality control applications.

  12. Soft Sensor for Inputs and Parameters Using Nonlinear Singular State Observer in Chemical Processes

    Institute of Scientific and Technical Information of China (English)

    许锋; 汪晔晔; 罗雄麟

    2013-01-01

    Chemical processes are usually nonlinear singular systems. In this study, a soft sensor using nonlinear singular state observer is established for unknown inputs and uncertain model parameters in chemical processes, which are augmented as state variables. Based on the observability of the singular system, this paper presents a simplified observability criterion under certain conditions for unknown inputs and uncertain model parameters. When the observability is satisfied, the unknown inputs and the uncertain model parameters are estimated online by the soft sensor using augmented nonlinear singular state observer. The riser reactor of fluid catalytic cracking unit is used as an example for analysis and simulation. With the catalyst circulation rate as the only unknown input without model error, one temperature sensor at the riser reactor outlet will ensure the correct estimation for the catalyst cir-culation rate. However, when uncertain model parameters also exist, additional temperature sensors must be used to ensure correct estimation for unknown inputs and uncertain model parameters of chemical processes.

  13. B{sub 36} borophene as an electronic sensor for formaldehyde: Quantum chemical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Shahbazi Kootenaei, Amirhossein, E-mail: a.kootenaei@gmail.com [Department of Chemical Engineering, Mahshahr Branch, Islamic Azad University, Mahshahr (Iran, Islamic Republic of); Ansari, Goodarz [Department of Chemistry, Mahshahr Branch, Islamic Azad University, Mahshahr (Iran, Islamic Republic of)

    2016-08-06

    Pristine carbon nanotubes and graphene show great sensitivity toward several lethal gases but cannot identify some extremely toxic chemicals such as formaldehyde (HCOH). Recent successful synthesis of all-boron graphene-like sheets attracted strong interest in exploring their possible applications. Herein, we inspected the potential application of B{sub 36} borophene sheet as a sensor for HCOH detection, using density functional theory computations. Different theoretical levels including B97D and Minnesota 06 functionals with different basis sets were employed. It was predicted that the electrical conductivity of B{sub 36} borophene significantly increases at the presence of HCOH molecules, thereby generating an electrical signal. The electrical signal is increased by increasing the number of adsorbed HCOH molecules, indicating that this sensor is sensitive to the concentration (or pressure) of HCOH gas. These results suggest that the pristine borophene may be used in the HCOH chemical sensors. - Highlights: • B{sub 36} borophene sheet can be used as a chemical sensor for HCOH detection. • The B{sub 36} is sensitive to the concentration of HCOH. • When the B{sub 36} adsorbs HCOH molecules, it is converted to a p-type semiconductor.

  14. Chemical Contamination Sensor for Phosphate Ester Hydraulic Fluids

    Directory of Open Access Journals (Sweden)

    Sumit Paul

    2010-01-01

    Full Text Available The paper deals with chemical contamination monitoring in phosphate-ester-based hydraulic fluids using nondispersive infrared (NDIR optical absorption. Our results show that NDIR monitoring allows detecting the take-up of water into such fluids and their hydrolytic disintegration as these become additionally stressed by Joule heating. Observations on the O–H stretching vibration band (3200–3800 cm−1 are used for determining the free water content (0–1.5% and the Total Acid Number (0–1 mgKOH/g. Both quantities can be assessed by monitoring the strength and the asymmetry of the O–H vibration band with regard to the free water absorption band centred around 3500 cm−1. As such optical parameters can be assessed without taking fluid samples from a pressurised hydraulic system, fluid degradation trends can be established based on regular measurements, before irreversible damage to the fluid has occurred. Therefore maintenance actions can be planned accordingly, which is very important for the airline, as unscheduled maintenance disturbs the flights organisation and often generates money loss.

  15. Carbon Nanotubes as a chemical sensor: Six membered ring molecules

    Science.gov (United States)

    Sumanasekera, G. U.; Adu, C. K. A.; Pradhan, B. K.; Romero, H. E.; Eklund, P. C.

    2002-03-01

    The thermoelectric response of a mat of a carbon nanotubes has been shown to be sensitive to the details of the molecule-SWNT interaction. In this presentation, we consider the effects of the adsorption of the six-membered-ring hydrocarbon molecules with varying π electron population (C_6H_n; n=6,8,10,12), heteroatoms (N), and adducts, etc. A wide variety of the thermoelectric response to these similar molecules is observed. For example, adsorption of Benzene (n=6) induces a giant increase of the thermopower, even reversing the sign. As the π electrons of the molecule are removed (i.e., increasing hydrogenation), the effect disapears. Thus, a selective chemical response is observed. The phenomenon is identied with scattering driven by the coupling of the π electrons in the molecule and the nanotube wall. Pyridine, on the otherhand, drives the thermopower more negative, and decreases the resistivity, suggesting charge transfer between nanotube and adsorbed molecule. Work supported by ONR # N00014-99-1-0619

  16. Gravimetric chemical sensors based on silica-based mesoporous organic-inorganic hybrids.

    Science.gov (United States)

    Xu, Jiaqiang; Zheng, Qi; Zhu, Yongheng; Lou, Huihui; Xiang, Qun; Cheng, Zhixuan

    2014-09-01

    Silica-based mesoporous organic-inorganic hybrid material modified quartz crystal microbalance (QCM) sensors have been examined for their ability to achieve highly sensitive and selective detection. Mesoporous silica SBA-15 serves as an inorganic host with large specific surface area, facilitating gas adsorption, and thus leads to highly sensitive response; while the presence of organic functional groups contributes to the greatly improved specific sensing property. In this work, we summarize our efforts in the rational design and synthesis of novel sensing materials for the detection of hazardous substances, including simulant nerve agent, organic vapor, and heavy metal ion, and develop high-performance QCM-based chemical sensors.

  17. Surface plasmon resonance based fibre optic chemical sensor for the detection of cocaine

    Science.gov (United States)

    Nguyen, T. Hien; Sun, Tong; Grattan, Kenneth T. V.

    2016-05-01

    A surface plasmon based fibre-optic chemical sensor for the detection of cocaine has been developed using a molecularly imprinted polymer (MIP) film with embedded gold nanoparticles as the recognition element. The MIP was formed on the layer of gold thin film which was deposited on the surface of a fibre core. The sensing was based on swelling of the MIP film induced by analyte binding that shifted the resonance spectrum toward a shorter wavelength. The sensor exhibited a response to cocaine in the concentration range of 0 - 400 μM in aqueous acetonitrile mixtures. Selectivity for cocaine over other drugs has also been demonstrated.

  18. Field-effect-based multifunctional hybrid sensor module for the determination of both (bio-)chemical and physical parameters

    Science.gov (United States)

    Schoening, Michael J.; Poghossian, Arshak; Schultze, J. Walter; Lueth, Hans

    2002-02-01

    Sensor systems for multi-parameter detection in fluidics usually combine different sensors, which are designed to detect either a physical or (bio-)chemical parameter. Therefore, such systems include a more complicated fabrication technology and measuring set-up. In this work, an ISFET (ion-sensitive field-effect transistor), which is well known as a (bio-)chemical sensor, is utilized as transducer for the detection of both (bio-)chemical and physical parameters. A multifunctional hybrid module for the determination of two (bio-)chemical parameters (pH, penicillin concentration) and three physical parameters (temperature, flow velocity and flow direction) using only two sensor structures, an ion generator and a reference electrode, is realized and its performance has been investigated. Here, a multifunctionality of the sensor system is achieved by means of different sensor arrangements and/or different operation modes. A Ta2O5-gate ISFET was used as transducer for all sensors. A novel time-of-flight type ISFET-based flow-velocity (flow rate) and flow-direction sensor using in-situ electrochemical generation of chemical tracers is presented. Due to the fast response of the ISFET (usually in the millisecond range), an ISFET-based flow sensor is suitable for the measurement of the flow velocity in a wide range. With regard to practical applications, pH measurements with this ISFET were performed in rain droplets.

  19. Microstructured and Photonic Bandgap Fibers for Applications in the Resonant Bio- and Chemical Sensors

    Directory of Open Access Journals (Sweden)

    Maksim Skorobogatiy

    2009-01-01

    Full Text Available We review application of microstructured and photonic bandgap fibers for designing resonant optical sensors of changes in the value of analyte refractive index. This research subject has recently invoked much attention due to development of novel fiber types, as well as due to development of techniques for the activation of fiber microstructure with functional materials. Particularly, we consider two sensors types. The first sensor type employs hollow core photonic bandgap fibers where core guided mode is confined in the analyte filled core through resonant effect in the surrounding periodic reflector. The second sensor type employs metalized microstructured or photonic bandgap waveguides and fibers, where core guided mode is phase matched with a plasmon propagating at the fiber/analyte interface. In resonant sensors one typically employs fibers with strongly nonuniform spectral transmission characteristics that are sensitive to changes in the real part of the analyte refractive index. Moreover, if narrow absorption lines are present in the analyte transmission spectrum, due to Kramers-Kronig relation this will also result in strong variation in the real part of the refractive index in the vicinity of an absorption line. Therefore, resonant sensors allow detection of minute changes both in the real part of the analyte refractive index (10−6–10−4 RIU, as well as in the imaginary part of the analyte refractive index in the vicinity of absorption lines. In the following we detail various resonant sensor implementations, modes of operation, as well as analysis of sensitivities for some of the common transduction mechanisms for bio- and chemical sensing applications. Sensor designs considered in this review span spectral operation regions from the visible to terahertz.

  20. Recent advances in gas and chemical detection by Vernier effect-based photonic sensors.

    Science.gov (United States)

    La Notte, Mario; Troia, Benedetto; Muciaccia, Tommaso; Campanella, Carlo Edoardo; De Leonardis, Francesco; Passaro, Vittorio M N

    2014-03-10

    Recently, the Vernier effect has been proved to be very efficient for significantly improving the sensitivity and the limit of detection (LOD) of chemical, biochemical and gas photonic sensors. In this paper a review of compact and efficient photonic sensors based on the Vernier effect is presented. The most relevant results of several theoretical and experimental works are reported, and the theoretical model of the typical Vernier effect-based sensor is discussed as well. In particular, sensitivity up to 460 μm/RIU has been experimentally reported, while ultra-high sensitivity of 2,500 μm/RIU and ultra-low LOD of 8.79 × 10(-8) RIU have been theoretically demonstrated, employing a Mach-Zehnder Interferometer (MZI) as sensing device instead of an add drop ring resonator.

  1. Recent Advances in Gas and Chemical Detection by Vernier Effect-Based Photonic Sensors

    Directory of Open Access Journals (Sweden)

    Mario La Notte

    2014-03-01

    Full Text Available Recently, the Vernier effect has been proved to be very efficient for significantly improving the sensitivity and the limit of detection (LOD of chemical, biochemical and gas photonic sensors. In this paper a review of compact and efficient photonic sensors based on the Vernier effect is presented. The most relevant results of several theoretical and experimental works are reported, and the theoretical model of the typical Vernier effect-based sensor is discussed as well. In particular, sensitivity up to 460 μm/RIU has been experimentally reported, while ultra-high sensitivity of 2,500 μm/RIU and ultra-low LOD of 8.79 × 10−8 RIU have been theoretically demonstrated, employing a Mach-Zehnder Interferometer (MZI as sensing device instead of an add drop ring resonator.

  2. Low Pass Filter Model for Chemical Sensors in Response to Gases and Odors

    Directory of Open Access Journals (Sweden)

    Mahmoud Z. Iskandarani

    2012-01-01

    Full Text Available Design and Modeling multi-gap sensing odor system for the objectives of odor recognition, classification and correlation are carried out. The model illustrates the low pass functionality of the multi-gap sensor acting as a filter for odors. Problem statement: Odor filtering is an important issue in today's world. In addition knowing the original material that an odor belongs to even after being mixed with others is also of vital importance. In addition measuring quality of mixed odors in terms of their affinity and belonging to a specific category or is critical. Approach: Mathematical modeling using low pass filter is carried out. Results: Clear evidence of ability to filter components of an odor mixture as the multi-gap sensor is acting as a filter. Conclusion: The ability to custom design chemical sensors to indicate the presence of various odors.

  3. pH-responsive fluorescence chemical sensor constituted by conjugated polymers containing pyridine rings.

    Science.gov (United States)

    Adachi, Naoya; Kaneko, Yuki; Sekiguchi, Kazuki; Sugiyama, Hiroki; Sugeno, Masafumi

    2015-12-01

    Poly(p-pyridinium phenylene ethynylene)s (PPyPE) functionalized with alternating donor-acceptor repeat units were synthesized by a Pd-catalyzed Sonogashira coupling reaction between diethynyl monomer and di-iodopyridine for use as a pH-responsive fluorescence chemical sensor. The synthesized PPyPE, containing pyridine units, was characterized by FT-IR, (1)H and (13)C NMR, UV-visible and fluorescence spectroscopies. We investigated the relationship between changes of optical properties and protonation/deprotonation of PPyPE containing pyridine units in solution. Addition of HCl decreased and red-shifted the fluorescence intensity of the conjugated polymers that contained pyridine rings; fluorescence intensity of the polymers increased upon addition of NaOH solution. The synthesized PPyPE was found to be an effective and reusable chemical sensor for pH sensing.

  4. Chemical sensors for classification of mine-like objects by identification of explosives

    Energy Technology Data Exchange (ETDEWEB)

    Woodfin, R.L.

    1997-10-01

    This paper briefly describes a prototype sensor for detecting land mines placed in shallow water. An automatic system was developed which incorporates chemical concentration technology, an ion mobility spectrometer, and control and fluid movement subsystems. The system design was successfully demonstrated using laboratory instruments and equipment. Components for the portable unit, which will weigh less than 20 pounds, have been fabricated; field demonstrations will be completed by spring 1998. 4 figs.

  5. Chemical Sensor Platform for Non-Invasive Monitoring of Activity and Dehydration

    Directory of Open Access Journals (Sweden)

    Dmitry Solovei

    2015-01-01

    Full Text Available A non-invasive solution for monitoring of the activity and dehydration of organisms is proposed in the work. For this purpose, a wireless standalone chemical sensor platform using two separate measurement techniques has been developed. The first approach for activity monitoring is based on humidity measurement. Our solution uses new humidity sensor based on a nanostructured TiO2 surface for sweat rate monitoring. The second technique is based on monitoring of potassium concentration in urine. High level of potassium concentration denotes clear occurrence of dehydration. Furthermore, a Wireless Body Area Network (WBAN was developed for this sensor platform to manage data transfer among devices and the internet. The WBAN coordinator controls the sensor devices and collects and stores the measured data. The collected data is particular to individuals and can be shared with physicians, emergency systems or athletes’ coaches. Long-time monitoring of activity and potassium concentration in urine can help maintain the appropriate water intake of elderly people or athletes and to send warning signals in the case of near dehydration. The created sensor system was calibrated and tested in laboratory and real conditions as well. The measurement results are discussed.

  6. A Compact, Low-Power Cantilever-Based Sensor Array for Chemical Detection

    Energy Technology Data Exchange (ETDEWEB)

    Loui, A; Ratto, T; Wilson, T; Mukerjee, E; Hu, Z; Sulchek, T; Hart, B

    2007-02-22

    A compact and low-power cantilever-based sensor array has been developed and used to detect various vapor analytes. This device employs sorptive polymers that are deposited onto piezoresistive cantilevers. We have successfully detected several organic vapors, representing a breadth of chemical properties and over a range of concentrations. Comparisons of the polymer/vapor partition coefficient to the cantilever deflection responses show that a simple linear relationship does not exist, emphasizing the need to develop an appropriate functional model to describe the chemical-to-mechanical transduction that is unique to this sensing modality.

  7. Intrinsic Fabry-Perot Interferometeric Sensor Based on Microfiber Created by Chemical Etching

    Directory of Open Access Journals (Sweden)

    Ruohui Wang

    2014-09-01

    Full Text Available An intrinsic Fabry-Perot interferometeric sensor based on a microfiber has been demonstrated. The micro-size suspended core is created by chemical etching a photonics crystal fiber, of which the cladding has a micrometer-spaced, hexagonal array of air holes. The sensing head is fabricated by chemical etching a short section of photonics crystal fiber spliced with a single mode fiber. The temperature sensing characteristic of the interferometer has also been demonstrated and a sensitivity 14.3 pm/°C is obtained.

  8. Biologically inspired large scale chemical sensor arrays and embedded data processing

    Science.gov (United States)

    Marco, S.; Gutiérrez-Gálvez, A.; Lansner, A.; Martinez, D.; Rospars, J. P.; Beccherelli, R.; Perera, A.; Pearce, T.; Vershure, P.; Persaud, K.

    2013-05-01

    Biological olfaction outperforms chemical instrumentation in specificity, response time, detection limit, coding capacity, time stability, robustness, size, power consumption, and portability. This biological function provides outstanding performance due, to a large extent, to the unique architecture of the olfactory pathway, which combines a high degree of redundancy, an efficient combinatorial coding along with unmatched chemical information processing mechanisms. The last decade has witnessed important advances in the understanding of the computational primitives underlying the functioning of the olfactory system. EU Funded Project NEUROCHEM (Bio-ICT-FET- 216916) has developed novel computing paradigms and biologically motivated artefacts for chemical sensing taking inspiration from the biological olfactory pathway. To demonstrate this approach, a biomimetic demonstrator has been built featuring a large scale sensor array (65K elements) in conducting polymer technology mimicking the olfactory receptor neuron layer, and abstracted biomimetic algorithms have been implemented in an embedded system that interfaces the chemical sensors. The embedded system integrates computational models of the main anatomic building blocks in the olfactory pathway: the olfactory bulb, and olfactory cortex in vertebrates (alternatively, antennal lobe and mushroom bodies in the insect). For implementation in the embedded processor an abstraction phase has been carried out in which their processing capabilities are captured by algorithmic solutions. Finally, the algorithmic models are tested with an odour robot with navigation capabilities in mixed chemical plumes

  9. Development of Magnetically Excited Flexural Plate Wave Devices for Implementation as Physical, Chemical, and Acoustic Sensors, and as Integrated Micro-Pumps for Sensored Systems

    Science.gov (United States)

    Schubert, W. K.; Mitchell, M. A.; Graf, D. C.; Shul, R. J.

    2002-05-01

    The magnetically excited flexural plate wave (mag-FPW) device has great promise as a versatile sensor platform. FPW's can have better sensitivity at lower operating frequencies than surface acoustic wave (SAW) devices. Lower operating frequency simplifies the control electronics and makes integration of sensor with electronics easier. Magnetic rather than piezoelectric excitation of the FPW greatly simplifies the device structure and processing by eliminating the need for piezoelectric thin films, also simplifying integration issues. The versatile mag-FPW resonator structure can potentially be configured to fulfill a number of critical functions in an autonomous sensored system. As a physical sensor, the device can be extremely sensitive to temperature, fluid flow, strain, acceleration and vibration. By coating the membrane with self-assembled monolayers (SAMs), or polymer films with selective absorption properties (originally developed for SAW sensors), the mass sensitivity of the FPW allows it to be used as biological or chemical sensors. Yet another critical need in autonomous sensor systems is the ability to pump fluid. FPW structures can be configured as micro-pumps. This report describes work done to develop mag-FPW devices as physical, chemical, and acoustic sensors, and as micro-pumps for both liquid and gas-phase analytes to enable new integrated sensing platform.

  10. High Sensitivity, Low Power Nano Sensors and Devices for Chemical Sensing

    Science.gov (United States)

    Li, Jing; Powell, Dan; Getty, Stephanie; Lu, Yi-Jiang

    2004-01-01

    The chemical sensor market has been projected to grow to better than $40 billion dollars worldwide within the next 10 years. Some of the primary motivations to develop nanostructured chemical sensors are monitoring and control of environmental pollution; improved diagnostics for consumption; improvement in measurement precision and accuracy; and improved detection limits for Homeland security, battlefield environments, and process and quality control of industrial applications. In each of these applications, there is demand for sensitivity, selectivity and stability of environmental and biohazard detection and capture beyond what is currently commercially available. Nanotechnology offers the ability to work at the molecular level, atom by atom, to create large structures with fundamentally new molecular organization. It is essentially concerned with materials, devices, and systems whose structures and components exhibit novel and significantly improved physical, chemical and biological properties, phenomena, and process control due to their nanoscale size. One such nanotechnology-enabled chemical sensor has been developed at NASA Ames leveraging nanostructures, such as single walled carbon nanotubes (SWNTs) and metal oxide nanobelts or nanowires, as a sensing medium bridging a pair of interdigitated electrodes (IDE) realized through a silicon-based microfabrication and micromachining technique. The DE fingers are fabricated on a silicon substrate using standard photolithography and thin film metallization techniques. It is noteworthy that the fabrication techniques employed are not confined to the silicon substrate. Through spin casting and careful substrate selection (i.e. clothing, glass, polymer, etc.), additional degrees of freedom can be exploited to enhance sensitivity or to conform to unique applications. Both in-situ growth of nanostructured materials and casting of nanostructured dispersions were used to produce analogous chemical sensing devices.

  11. Detection of trace elements in DI water and comparison of several water solutions by using EF-FLRD chemical sensors

    Science.gov (United States)

    Kaya, M.; Wang, C.

    2017-02-01

    Detection of trace elements in DI water and comparison of several types of water respons such as DI water, tap water, and ocean water were studied by using EF-FLRD chemical sensors. Solutions of Mg, Fe, P, and Cd elements with a concentration of 1000 µg/ml (1 mg/ml) which corresponds to 1000 ppm by weight were tested. DI water, tap water, and real ocean water were utilized as medium to observe refractive index difference of solutions. The EF sensing technique which is based on the EF scattering effect was employed for the detection of trace chemicals and recording of solution responses. Due to the refractive index differences between solutions, optical loss of the sensor was different when the sensor head was immersed into solutions of approximately 10 ml each. The differences of the refractive indices are presented by recording ringdown times when the sensor head was immersed into the solutions. Fast response (˜1s), high sensitive, and reproducible EF-FLRD chemical sensors were fabricated and tested in laboratory conditions. High sensitivity of the sensors due to being capability of detecting smaller differences between measurands without any additional components or treatment makes the EF-FLRD sensors more attractive. Enhanced sensitivity of the EF-FLRD chemical sensors as a result of the multi-pass nature of the FLRD technique has potential application in detecting of trace elements in monitoring of water quality.

  12. Paper-based capacitive sensors for identification and quantification of chemicals at the point of care.

    Science.gov (United States)

    Hu, Jie; Yew, Chee-Hong Takahiro; Chen, Xiaoshuang; Feng, Shangsheng; Yang, Qu; Wang, Shuqi; Wee, Wei-Hong; Pingguan-Murphy, Belinda; Lu, Tian Jian; Xu, Feng

    2017-04-01

    The identification and quantification of chemicals play a vital role in evaluation and surveillance of environmental health and safety. However, current techniques usually depend on costly equipment, professional staff, and/or essential infrastructure, limiting their accessibility. In this work, we develop paper-based capacitive sensors (PCSs) that allow simple, rapid identification and quantification of various chemicals from microliter size samples with the aid of a handheld multimeter. PCSs are low-cost parallel-plate capacitors (~$0.01 per sensor) assembled from layers of aluminum foil and filter paper via double-sided tape. The developed PCSs can identify different kinds of fluids (e.g., organic chemicals) and quantify diverse concentrations of substances (e.g., heavy metal ions) based on differences in dielectric properties, including capacitance, frequency spectrum, and dielectric loss tangent. The PCS-based method enables chemical identification and quantification to take place much cheaply, simply, and quickly at the point-of-care (POC), holding great promise for environmental monitoring in resource-limited settings.

  13. A molecularly imprinted polymer (MIP)-coated microbeam MEMS sensor for chemical detection

    Science.gov (United States)

    Holthoff, Ellen L.; Li, Lily; Hiller, Tobias; Turner, Kimberly L.

    2015-05-01

    Recently, microcantilever-based technology has emerged as a viable sensing platform due to its many advantages such as small size, high sensitivity, and low cost. However, microcantilevers lack the inherent ability to selectively identify hazardous chemicals (e.g., explosives, chemical warfare agents). The key to overcoming this challenge is to functionalize the top surface of the microcantilever with a receptor material (e.g., a polymer coating) so that selective binding between the cantilever and analyte of interest takes place. Molecularly imprinted polymers (MIPs) can be utilized as artificial recognition elements for target chemical analytes of interest. Molecular imprinting involves arranging polymerizable functional monomers around a template molecule followed by polymerization and template removal. The selectivity for the target analyte is based on the spatial orientation of the binding site and covalent or noncovalent interactions between the functional monomer and the analyte. In this work, thin films of sol-gel-derived xerogels molecularly imprinted for TNT and dimethyl methylphosphonate (DMMP), a chemical warfare agent stimulant, have demonstrated selectivity and stability in combination with a fixed-fixed beam microelectromechanical systems (MEMS)-based gas sensor. The sensor was characterized by parametric bifurcation noise-based tracking.

  14. Chemically robust platform for optical solid-state conducting polymer sensor

    Science.gov (United States)

    Holt, A. L.; Bearinger, J. P.; Carter, S. A.

    2006-10-01

    Conjugated polymers are unique materials for use in the development of chemical and biological sensors because of their widely tunable optical and electrical properties that allow them dual functionality as both the sensing element and the signal transducer. Furthermore, as optical photoluminescence based sensors, electroactive polymers are found to exhibit high sensitivity due to the ability of the analyte of interest to quench the photoluminescence of the entire polymer chain. In order to produce a more chemically robust thin film for use as a "solid-state" optical sensor, we succeeded in grafting various poly (3-alkyl-thiophene)s to optically transparent substrates such as glass, quartz, and ITO coated glass. This was accomplished by first grafting a thiophene monomer to the surface then chemically growing the films via oxidative polymerization. XPS studies indicated that each chemical step was accurately understood. The polythiophene growth, unaltered by sonication and tape peeling tests, was uniform across the substrate and could be directed by selective silanization of the substrate. Film thicknesses range from 20 to 200 nm and exhibit varying degrees of surface roughness, depending on the polymerization process. The reaction times and solvents were varied in order to optimize the desired film properties. The absorption and photoluminescence properties of the thin films compared well with literature on spun-cast polythiophene films, as did the electrical conductivities of the doped and undoped material. The photoluminescence intensities of the films are found to be unaffected by paraquat in water but are sensitive to trace amounts of ferric chloride in acetonitrile with measurable Stern Volmer constants.

  15. Guided shear horizontal surface acoustic wave sensors for chemical and biochemical detection in liquids.

    Science.gov (United States)

    Josse, F; Bender, F; Cernose, R W

    2001-12-15

    The design and performance of guided shear horizontal surface acoustic wave (guided SH-SAW) devices on LiTaO3 substrates are investigated for high-sensitivity chemical and biochemical sensors in liquids. Despite their structural similarity to Rayleigh SAW, SH-SAWs often propagate slightly deeper within the substrate, hence preventing the implementation of high-sensitivity detectors. The device sensitivity to mass and viscoelastic loading is increased using a thin guiding layer on the device surface. Because of their relatively low shear wave velocity, various polymers including poly(methyl methacrylate) (PMMA) and cyanoethyl cellulose (cured or cross-linked) are investigated as the guiding layers to trap the acoustic energy near the sensing surface. The devices have been tested in biosensing and chemical sensing experiments. Suitable design principles for these applications are discussed with regard to wave guidance, electrical passivation of the interdigital transducers from the liquid environments, acoustic loss, and sensor signal distortion. In biosensing experiments, using near-optimal PMMA thickness of approximately 2 microm, mass sensitivity greater than 1500 Hz/(ng/mm2) is demonstrated, resulting in a minimum detection limit less than 20 pg/mm2. For chemical sensor experiments, it is found that optimal waveguide thickness must be modified to account for the chemically sensitive layer which also acts to guide the SH-SAW. A detection limit of 780 (3 x peak-to-peak noise) or 180 ppb (3 x rms noise) is estimated from the present measurements for some organic compounds in water.

  16. Chemical Discrimination in Turbulent Gas Mixtures with MOX Sensors Validated by Gas Chromatography-Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Jordi Fonollosa

    2014-10-01

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

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

    Science.gov (United States)

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

    2014-10-16

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

  18. G3 Assisted Rational Design of Chemical Sensor Array Using Carbonitrile Neutral Receptors

    Directory of Open Access Journals (Sweden)

    Yatimah Alias

    2013-10-01

    Full Text Available Combined computational and experimental strategies for the systematic design of chemical sensor arrays using carbonitrile neutral receptors are presented. Binding energies of acetonitrile, n-pentylcarbonitrile and malononitrile with Ca(II, Mg(II, Be(II and H+ have been investigated with the B3LYP, G3, CBS-QB3, G4 and MQZVP methods, showing a general trend H+ > Be(II > Mg(II > Ca(II. Hydrogen bonding, donor-acceptor and cation-lone pair electron simple models were employed in evaluating the performance of computational methods. Mg(II is bound to acetonitrile in water by 12.5 kcal/mol, and in the gas phase the receptor is more strongly bound by 33.3 kcal/mol to Mg(II compared to Ca(II. Interaction of bound cations with carbonitrile reduces the energies of the MOs involved in the proposed σ-p conjugated network. The planar malononitrile-Be(II complex possibly involves a π-network with a cationic methylene carbon. Fabricated potentiometric chemical sensors show distinct signal patterns that can be exploited in sensor array applications.

  19. Review of sensors for the in situ chemical characterization of the Hanford underground storage tanks

    Energy Technology Data Exchange (ETDEWEB)

    Kyle, K.R.; Mayes, E.L.

    1994-07-29

    Lawrence Livermore National Laboratory (LLNL), in the Technical Task Plan (TTP) SF-2112-03 subtask 2, is responsible for the conceptual design of a Raman probe for inclusion in the in-tank cone penetrometer. As part of this task, LLNL is assigned the further responsibility of generating a report describing a review of sensor technologies other than Raman that can be incorporated in the in-tank cone penetrometer for the chemical analysis of the tank environment. These sensors would complement the capabilities of the Raman probe, and would give information on gaseous, liquid, and solid state species that are insensitive to Raman interrogation. This work is part of a joint effort involving several DOE laboratories for the design and development of in-tank cone penetrometer deployable systems for direct UST waste characterization at Westinghouse Hanford Company (WHC) under the auspices of the U.S. Department of Energy (DOE) Underground Storage Tank Integrated Demonstration (UST-ID).

  20. Oil degradation monitoring with chemical sensors and molecular imprinted polymer; Monitorizacion de la degradacion de aceites con sensores quimicos y polimeros de impronta molecular

    Energy Technology Data Exchange (ETDEWEB)

    Calvo, J.L.; Meizoso, M.C.; Gonzalez Rodriguez, M.V.; Lopez Vilarino, J.M.; Cela, M.C.

    2010-07-01

    The engine operation state can be reported by real-time monitoring programs. Detecting early signs of equipment failure is the aim of these maintenance programs.Chemical sensors are devices that can perform this function in predictive maintenance.The monitoring of the degradation of automotive engine oils has been achieved by chemical sensors coated with synthetic recognition elements. Following, the elements that make up the QCM device, MIPs, organic-inorganic hybrid materials obtained by sol-gel and electronic packaging are described. (Author).

  1. Two-Dimensional Atomic-Layered Alloy Junctions for High-Performance Wearable Chemical Sensor.

    Science.gov (United States)

    Cho, Byungjin; Kim, Ah Ra; Kim, Dong Jae; Chung, Hee-Suk; Choi, Sun Young; Kwon, Jung-Dae; Park, Sang Won; Kim, Yonghun; Lee, Byoung Hun; Lee, Kyu Hwan; Kim, Dong-Ho; Nam, Jaewook; Hahm, Myung Gwan

    2016-08-03

    We first report that two-dimensional (2D) metal (NbSe2)-semiconductor (WSe2)-based flexible, wearable, and launderable gas sensors can be prepared through simple one-step chemical vapor deposition of prepatterned WO3 and Nb2O5. Compared to a control device with a Au/WSe2 junction, gas-sensing performance of the 2D NbSe2/WSe2 device was significantly enhanced, which might have resulted from the formation of a NbxW1-xSe2 transition alloy junction lowering the Schottky barrier height. This would make it easier to collect charges of channels induced by molecule adsorption, improving gas response characteristics toward chemical species including NO2 and NH3. 2D NbSe2/WSe2 devices on a flexible substrate provide gas-sensing properties with excellent durability under harsh bending. Furthermore, the device stitched on a T-shirt still performed well even after conventional cleaning with a laundry machine, enabling wearable and launderable chemical sensors. These results could pave a road toward futuristic gas-sensing platforms based on only 2D materials.

  2. Chemical Sensors Based on IR Spectroscopy and Surface-Modified Waveguides

    Science.gov (United States)

    Lopez, Gabriel P.; Niemczyk, Thomas

    1999-01-01

    Sol-gel processing techniques have been used to apply thin porous films to the surfaces of planar infrared (IR) waveguides to produce widely useful chemical sensors. The thin- film coating serves to diminish the concentration of water and increase the concentration of the analyte in the region probed by the evanescent IR wave. These porous films are composed of silica, and therefore, conventional silica surface modification techniques can be used to give the surface a specific functional character. The sol-gel film was surface-modified to make the film highly hydrophobic. These sensors were shown to be capable of detecting non-polar organic analytes, such as benzonitrile, in aqueous solution with detection limits in the ppb range. Further, these porous sol-gel structures allow the analytes to diffuse into and out of the films rapidly, thus reaching equilibrium in less than ten seconds. These sensors are unique because of the fact that their operation is based on the measurement of an IR absorption spectrum. Thus, these sensors are able to identify the analytes as well as measure concentration with high sensitivity. These developments have been documented in previous reports and publications. Recently, we have also targeted detection of the polar organic molecules acetone and isopropanol in aqueous solution. Polar organics are widely used in industrial and chemical processes, hence it is of interest to monitor their presence in effluents or decontamination process flows. Although large improvements in detection limits were expected with non-polar organic molecules in aqueous solutions using very hydrophobic porous sol-gel films on silicon attenuated total reflectance (Si ATR) waveguides, it was not as clear what the detection enhancements might be for polar organic molecules. This report describes the use of modified sol-gel-coated Si ATR sensors for trace detection and quantitation of small polar organic molecules in aqueous solutions. The detection of both acetone

  3. Electrocatalytic Organic-Inorganic Hybrid Films and Their Applications in Chemical Sensors and Biosensors

    Institute of Scientific and Technical Information of China (English)

    LI; XiaoYuan

    2001-01-01

    In this report, we will present the organic-inorganic hybrid molecular films prepared in our group and their applications in chemical sensors and biosensors.Many types of multi-layered films have been prepared in an alternatively assembled organic-inorganic and layer-by-layer manner. We will focus on the alternatively organized organic surfactant and metal-complex films and their conversion into electrocatalytically active films. Especially, we will demonstrate the preparation of bifunctional films for the detection of two different but correlated species, such as nitric oxide and oxygen, in biomedia.  ……

  4. Electrocatalytic Organic-Inorganic Hybrid Films and Their Applications in Chemical Sensors and Biosensors

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ In this report, we will present the organic-inorganic hybrid molecular films prepared in our group and their applications in chemical sensors and biosensors.Many types of multi-layered films have been prepared in an alternatively assembled organic-inorganic and layer-by-layer manner. We will focus on the alternatively organized organic surfactant and metal-complex films and their conversion into electrocatalytically active films. Especially, we will demonstrate the preparation of bifunctional films for the detection of two different but correlated species, such as nitric oxide and oxygen, in biomedia.

  5. Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, H. [PBI-Dansensor A/S (Denmark); Toft Soerensen, O. [Risoe National Lab., Materials Research Dept. (Denmark)

    1999-10-01

    A new type of ceramic oxygen sensors based on semiconducting oxides was developed in this project. The advantage of these sensors compared to standard ZrO{sub 2} sensors is that they do not require a reference gas and that they can be produced in small sizes. The sensor design and the techniques developed for production of these sensors are judged suitable by the participating industry for a niche production of a new generation of oxygen sensors. Materials research on new oxygen ion conducting conductors both for applications in oxygen sensors and in fuel was also performed in this project and finally a new process was developed for fabrication of ceramic tubes by dip-coating. (EHS)

  6. Sensors

    CERN Document Server

    Pigorsch, Enrico

    1997-01-01

    This is the 5th edition of the Metra Martech Directory "EUROPEAN CENTRES OF EXPERTISE - SENSORS." The entries represent a survey of European sensors development. The new edition contains 425 detailed profiles of companies and research institutions in 22 countries. This is reflected in the diversity of sensors development programmes described, from sensors for physical parameters to biosensors and intelligent sensor systems. We do not claim that all European organisations developing sensors are included, but this is a good cross section from an invited list of participants. If you see gaps or omissions, or would like your organisation to be included, please send details. The data base invites the formation of effective joint ventures by identifying and providing access to specific areas in which organisations offer collaboration. This issue is recognised to be of great importance and most entrants include details of collaboration offered and sought. We hope the directory on Sensors will help you to find the ri...

  7. Synthesis of copper telluride nanowires using template-based electrodeposition method as chemical sensor

    Indian Academy of Sciences (India)

    Sandeep Arya; Saleem Khan; Suresh Kumar; Rajnikant Verma; Parveen Lehana

    2013-08-01

    Copper telluride (CuTe) nanowires were synthesized electrochemically from aqueous acidic solution of copper (II) sulphate (CuSO4.5H2O) and tellurium oxide (TeO2) on a copper substrate by template-assisted electrodeposition method. The electrodeposition was conducted at 30 °C and the length of nanowires was controlled by adjusting deposition time. Structural characteristics were examined using X-ray diffraction and scanning electron microscope which confirm the formation of CuTe nanowires. Investigation for chemical sensing was carried out using air and chloroform, acetone, ethanol, glycerol, distilled water as liquids having dielectric constants 1, 4.81, 8.93, 21, 24.55, 42.5 and 80.1, respectively. The results unequivocally prove that copper telluride nanowires can be fabricated as chemical sensors with enhanced sensitivity and reliability.

  8. Characterization and application of PBA fiber optic chemical film sensor based on fluorescence multiple quenching

    Institute of Scientific and Technical Information of China (English)

    陈坚; 李伟; 阎超; 袁立懋; 郭炬亮; 周新继

    1997-01-01

    The three types of structure of the pyrenebutyric acid of fiber optic chemical film sensor were stud-ied by fluorescence multiple quenching. They are, for different test samples and purposes, respectively general, three-way and combined. A tri-cup method was designed to demonstrate the multiple quenching of response mechanism, and a relationship formula of mathematical approach was established. The response mechanism was shown to include the dynamic quenching , inner-filter effects and/or resonance energy transfer. To show the response characterization in a series of organic and inorganic quenchers, a new concept of apparent quenching coefficient Kq was advanced. This kind of sensor has been used in continuous and in situ monitoring of the dissolution rate of drug tablets, on line and in situ monitoring of some organic therapeutic drugs in biological fluid and Cr( VI ) in industrial waste water. The measured data were examined and compared with HPLC or HPTLCS. Test results show that the sensors and appa

  9. An efficient approach for preprocessing data from a large-scale chemical sensor array.

    Science.gov (United States)

    Leo, Marco; Distante, Cosimo; Bernabei, Mara; Persaud, Krishna

    2014-09-24

    In this paper, an artificial olfactory system (Electronic Nose) that mimics the biological olfactory system is introduced. The device consists of a Large-Scale Chemical Sensor Array (16; 384 sensors, made of 24 different kinds of conducting polymer materials)that supplies data to software modules, which perform advanced data processing. In particular, the paper concentrates on the software components consisting, at first, of a crucial step that normalizes the heterogeneous sensor data and reduces their inherent noise. Cleaned data are then supplied as input to a data reduction procedure that extracts the most informative and discriminant directions in order to get an efficient representation in a lower dimensional space where it is possible to more easily find a robust mapping between the observed outputs and the characteristics of the odors in input to the device. Experimental qualitative proofs of the validity of the procedure are given by analyzing data acquired for two different pure analytes and their binary mixtures. Moreover, a classification task is performed in order to explore the possibility of automatically recognizing pure compounds and to predict binary mixture concentrations.

  10. Mass sensitivity analysis and designing of surface acoustic wave resonators for chemical sensors

    Science.gov (United States)

    Kshetrimayum, Roshan; Yadava, R. D. S.; Tandon, R. P.

    2009-05-01

    The sensitivity of surface acoustic wave (SAW) chemical sensors depends on several factors such as the frequency and phase point of SAW device operation, sensitivity of the SAW velocity to surface mass loading, sensitivity of the SAW oscillator resonance to the loop phase shift, film thickness and oscillator electronics. This paper analyzes the influence of the phase point of operation in SAW oscillator sensors based on two-port resonator devices. It is found that the mass sensitivity will be enhanced if the SAW device has a nonlinear dependence on the frequency (delay ~ frequency-1). This requires the device to generate and operate in a ωτg(ω) = const region in the device passband, where ω denotes the angular frequency of oscillation and τg(ω) denotes the phase slope of the SAW resonator device. A SAW coupled resonator filter (CRF) that take advantage of mode coupling is considered in realizing such a device to help in shaping the phase transfer characteristics of a high mass sensitivity sensor. The device design and simulation results are presented within the coupling-of-modes formalism.

  11. Chalcogenide glass mid-infrared on-chip sensor for chemical sensing

    Science.gov (United States)

    Lin, Hongtao

    Chemical sensing in the mid-infrared (mid-IR) has been considered to be significant for molecular detection for decades, but until recently has mostly relied on benchtop spectroscopic instruments like Fourier transform infrared spectrometers, etc. Recent strides in planar photonic integration envision compact, standalone "sensor-on-a-chip" devices for molecular analysis as a potentially disruptive technology as compared to their conventional bulky counterparts. However, the difficulty of achieving adequate sensitivity in integrated optical sensors is still a key barrier towards their practical application, limited by the weak interactions between photons and molecules over the short optical path length accessible on a chip. To solve the sensitivity challenge, a novel mid-IR photothermal spectroscopic sensing technique was proposed and theoretically examined. Through dramatically amplified photothermal effects in an optical nano-cavity doubly resonant at both mid-IR pump and near infrared probe wavelengths, a device design based on nested 1-D nanobeam photonic crystal cavities is numerically analyzed to demonstrate the technique's potential for single small gas molecule detection without the need for cryogenically cooled mid-IR photo-detectors. Furthermore, since silica becomes opaque at wavelengths beyond 3.5 microm, new material platforms and fabrication techniques are needed for mid-IR on-chip chemical sensors. Chalcogenide glasses (ChG), amorphous compounds containing S, Se and Te, are ideal material choices for mid-IR chemical sensors given their broad mid-IR transparency window, large photothermal figure-of-merit, amorphous structure and low processing temperature. A ChG lift-off process and a nano-fabrication technique using focused ion beam milling have been developed to fabricate mid-IR ChG resonators and photonic crystal waveguide cavities. ChG resonators on CaF2 substrate claimed a high quality factor around 4 x 105. Using these devices, we have also

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

    Science.gov (United States)

    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

  13. Warped C80H30 nanographene as a chemical sensor for CO gas: DFT studies

    Science.gov (United States)

    Jameh-Bozorghi, Saeed; Soleymanabadi, Hamed

    2017-02-01

    In 2013, synthesis of a grossly warped nanographene (C80H30, NG) which was reported in Nature Chemistry opens a new avenue in carbonaceous nanomaterial research. Here we investigated the chemical reactivity and electronic sensitivity of this NG to carbon monoxide (CO) gas, using density functional theory calculations. It was found that the CO molecule prefers to be added to a C-C bond at the center of NG similarly to the [ 2 + 2] addition. The calculated adsorption energy which is about -10.92 kJ/mol is accompanied by a natural bond orbitals (NBO) charge transfer of 0.21 e from the NG to the CO molecule. Unlike the graphene, the electronic properties of NG are significantly affected by the CO adsorption. After the CO adsorption, the electrical conductivity of the NG is considerably increased which can be converted to an electrical signal. Thus, it is concluded that the NG may be a potential compound for the CO chemical sensors for which the pristine graphene is not appropriate. We demonstrated that by increasing the concentration of the CO molecules the electrical conductivity is increased more. Also, a short recovery time of about 83 ps is predicted for NG sensor.

  14. Microfluidic platforms employing integrated fluorescent or luminescent chemical sensors: a review of methods, scope and applications

    Science.gov (United States)

    Pfeiffer, Simon A.; Nagl, Stefan

    2015-09-01

    Herein we critically review microfluidic platforms that contain integrated fluorescent or luminescent chemical sensor assemblies. These were employed in particular for miniaturized oxygen and pH sensing. Microchips with optical temperature sensing capability are also covered since these share many concepts and applications. Other analytes and derived parameters from the above analytes are found in some sensing approaches in microfluidics. After an introduction, the work is structured into three main chapters dealing with the fabrication and microintegration of these sensors, readout and detection strategies, and applications of these microsystems. The fabrication is discussed with a focus on soft lithography-based approaches in polydimethylsiloxane (PDMS) or PDMS and glass hybrid devices that form the majority of work so far. Alternative approaches, particularly using glass or quartz as the main chip material are also covered. Detection techniques employed to date are the subject of the next chapter, where simple intensity as well as lifetime- or wavelength-referenced schemes are presented and the utility of image-based sensing on the microscale is discussed. Lastly, exciting applications of these microfluidic chips are highlighted. Luminescent oxygen and pH sensing has been of particular interest in the field of microbioreactors but other areas are also of interest, particularly chemical reactors and electrophoresis. Optical temperature sensing is discussed and its use in fundamental studies as well as in enzyme reactors. Integrated microsystems with biosensing capabilities and some for monitoring of metal ions and other analytes are also presented.

  15. A portable chemical sensor for histidine based on the strategy of click chemistry.

    Science.gov (United States)

    Zhou, Jin; Xu, Kefeng; Zhou, Ping; Zheng, Ou; Lin, Zhenyu; Guo, Longhua; Qiu, Bin; Chen, Guonan

    2014-01-15

    A novel portable chemical sensor is developed in combination of the personal glucose meters (PGM) with click chemistry for sensitive and selective determination of histidine. Invertase-labeled alkynyl-DNA can be modified onto the surfaces of Streptavidin Magnespheres Paramagnetic Particles (PMPs) through copper(I) catalyzed azide-alkyne cycloaddition (CuAAC) reaction and formed invertase-functionalized PMPs, which can be separated easily. The presence of invertase can convert sucrose to glucose and can be monitored by the PGM easily. The presence of histidine can inhibit the CuAAC, so the read-out signal of PGM decreased. The difference in signals from the PGM before and after addition of histidine has a good linear correlation with the logarithm of the histidine concentrations in the range of 0.01~100 μM with a detection limit of 3.4 nM, which is lower than those of many other chemical sensors. Moreover, the assay of histidine in milk samples is demonstrated with satisfactory results.

  16. Fiber optic chemical sensors: The evolution of high- density fiber-optic DNA microarrays

    Science.gov (United States)

    Ferguson, Jane A.

    2001-06-01

    Sensors were developed for multianalyte monitoring, fermentation monitoring, lactate analysis, remote oxygen detection for use in bioremediation monitoring and in a fuel spill clean-up project, heavy metal analysis, and high density DNA microarrays. The major focus of this thesis involved creating and improving high-density DNA gene arrays. Fiber optic sensors are created using fluorescent indicators, polymeric supports, and optical fiber substrates. The fluorescent indicator is entrapped in a polymer layer and attached to the tip of the optical fiber. The tip of the fiber bearing the sensing layer (the distal end) is placed in the sample of interest while the other end of the fiber (the proximal end) is connected to an analysis system. Any length of fiber can be used without compromising the integrity or sensitivity of the system. A fiber optic oxygen sensor was designed incorporating an oxygen sensitive fluorescent dye and a gas permeable polymer attached to an optical fiber. The construction simplicity and ruggedness of the sensor enabled its deployment for in situ chemical oxidation and bioremediation studies. Optical fibers were also used as the substrate to detect biomolecules in solution. To monitor bioprocesses, the production of the analyte of interest must be coupled with a species that is optically measurable. For example, oxygen is consumed in many metabolic functions. The fiber optic oxygen sensor is equipped with an additional sensing layer. Upon contact with a specific biochemical in the sample, a reaction occurs in the additional sensing layer that either consumes or produces oxygen. This dual layer system was used to monitor the presence of lactate, an important metabolite for clinical and bioprocess analysis. In many biological and environmental systems, the generation of one species occurs coincidentally with the generation or consumption of another species. A multianalyte sensor was prepared that can monitor the simultaneous activity of pH, CO2

  17. Investigation on dielectrophoretic assembly of nanostructures and its application on chemical sensors

    Science.gov (United States)

    Tao, Quan

    Because of their extraordinary characteristics such as quantum confinement and large surface-tovolume ratio, semiconducting nanostructures such as nanowires or nanotubes hold great potential in sensing chemical vapors. Nanowire or nanotube based gas sensors usually possess appealing advantages such as high sensitivity, high stability, fast recovery time, and electrically controllable properties. To better predict the composition and concentration of target gas, nanostructures made from heterogeneous materials are employed to provide more predictors. In recent years, nanowires and nanotubes can be synthesized routinely through different methods. The techniques of fabricating nanowire or nanotube based sensor arrays, however, encounter obstacles and deserve further investigations. Dielectrophoresis (DEP), which refers to the motion of submicron particles inside a non-uniform electric field, has long been recognized as a nondestructive, easily implementable, and efficient approach to manipulate nanostructures onto electronic circuitries. However, due to our limited understandings, devices fabricated through DEP often end up with unpredictable number of arbitrarily aligned nanostructures. In this study, we first optimize the classical DEP formulas such that it can be applied to a more general case that a nanostructure is subjected to a non-uniform electric field with arbitrary orientation. A comprehensive model is then constructed to investigate the trajectory and alignment of DEP assembled nanostructures, which can be verified by experimental observations. The simulation results assist us to fabricate a gas sensor array with zinc oxide (ZnO) nanowires and carbon nanotubes (CNTs). It is then demonstrated that the device can well sense ammonia (NH3) at room temperature, which circumvents the usually required high temperature condition for nanowire based gas sensor application. An effective approach to recover the device using DC biases to locally heat up the

  18. Functionalised zinc oxide nanowire gas sensors: Enhanced NO2 gas sensor response by chemical modification of nanowire surfaces

    Directory of Open Access Journals (Sweden)

    Eric R. Waclawik

    2012-05-01

    Full Text Available Surface coating with an organic self-assembled monolayer (SAM can enhance surface reactions or the absorption of specific gases and hence improve the response of a metal oxide (MOx sensor toward particular target gases in the environment. In this study the effect of an adsorbed organic layer on the dynamic response of zinc oxide nanowire gas sensors was investigated. The effect of ZnO surface functionalisation by two different organic molecules, tris(hydroxymethylaminomethane (THMA and dodecanethiol (DT, was studied. The response towards ammonia, nitrous oxide and nitrogen dioxide was investigated for three sensor configurations, namely pure ZnO nanowires, organic-coated ZnO nanowires and ZnO nanowires covered with a sparse layer of organic-coated ZnO nanoparticles. Exposure of the nanowire sensors to the oxidising gas NO2 produced a significant and reproducible response. ZnO and THMA-coated ZnO nanowire sensors both readily detected NO2 down to a concentration in the very low ppm range. Notably, the THMA-coated nanowires consistently displayed a small, enhanced response to NO2 compared to uncoated ZnO nanowire sensors. At the lower concentration levels tested, ZnO nanowire sensors that were coated with THMA-capped ZnO nanoparticles were found to exhibit the greatest enhanced response. ΔR/R was two times greater than that for the as-prepared ZnO nanowire sensors. It is proposed that the ΔR/R enhancement in this case originates from the changes induced in the depletion-layer width of the ZnO nanoparticles that bridge ZnO nanowires resulting from THMA ligand binding to the surface of the particle coating. The heightened response and selectivity to the NO2 target are positive results arising from the coating of these ZnO nanowire sensors with organic-SAM-functionalised ZnO nanoparticles.

  19. Chemical-Biological Properties of Zinc Sensors TSQ and Zinquin: Formation of Sensor-Zn-Protein Adducts versus Zn(Sensor)2 Complexes.

    Science.gov (United States)

    Nowakowski, Andrew B; Meeusen, Jeffrey W; Menden, Heather; Tomasiewicz, Henry; Petering, David H

    2015-12-21

    Fluorescent zinc sensors are the most commonly used tool to study the intracellular mobile zinc status within cellular systems. Previously, we have shown that the quinoline-based sensors Zinquin and 6-methoxy-8-p-toluenesulfonamido-quinoline (TSQ) predominantly form ternary adducts with members of the Zn-proteome. Here, the chemistries of these sensors are further characterized, including how Zn(sensor)2 complexes may react in an intracellular environment. We demonstrate that these sensors are typically used in higher concentrations than needed to obtain maximum signal. Exposing cells to either Zn(Zinquin)2 or Zn(TSQ)2 resulted in efficient cellular uptake and the formation of sensor-Zn-protein adducts as evidenced by both a fluorescence spectral shift toward that of ternary adducts and the localization of the fluorescence signal within the proteome after gel filtration of cellular lysates. Likewise, reacting Zn(sensor)2 with the Zn-proteome from LLC-PK1 cells resulted in the formation of sensor-Zn-protein ternary adducts that could be inhibited by first saturating the Zn- proteome with excess sensor. Further, a native SDS-PAGE analysis of the Zn-proteome reacted with either the sensor or the Zn(sensor)2 complex revealed that both reactions result in the formation of a similar set of sensor-Zn-protein fluorescent products. The results of this experiment also demonstrated that TSQ and Zinquin react with different members of the Zn-proteome. Reactions with the model apo-Zn-protein bovine serum albumin showed that both Zn(TSQ)2 and Zn(Zinquin)2 reacted to form ternary adducts with its apo-Zn-binding site. Moreover, incubating Zn(sensor)2 complexes with non-zinc binding proteins failed to elicit a spectral shift in the fluorescence spectrum, supporting the premise that blue-shifted emission spectra are due to sensor-Zn-protein ternary adducts. It was concluded that Zn(sensors)2 species do not play a significant role in the overall reaction between these sensors and

  20. Ammonia gas sensors based on chemically reduced graphene oxide sheets self-assembled on Au electrodes.

    Science.gov (United States)

    Wang, Yanyan; Zhang, Liling; Hu, Nantao; Wang, Ying; Zhang, Yafei; Zhou, Zhihua; Liu, Yanhua; Shen, Su; Peng, Changsi

    2014-01-01

    We present a useful ammonia gas sensor based on chemically reduced graphene oxide (rGO) sheets by self-assembly technique to create conductive networks between parallel Au electrodes. Negative graphene oxide (GO) sheets with large sizes (>10 μm) can be easily electrostatically attracted onto positive Au electrodes modified with cysteamine hydrochloride in aqueous solution. The assembled GO sheets on Au electrodes can be directly reduced into rGO sheets by hydrazine or pyrrole vapor and consequently provide the sensing devices based on self-assembled rGO sheets. Preliminary results, which have been presented on the detection of ammonia (NH3) gas using this facile and scalable fabrication method for practical devices, suggest that pyrrole-vapor-reduced rGO exhibits much better (more than 2.7 times with the concentration of NH3 at 50 ppm) response to NH3 than that of rGO reduced from hydrazine vapor. Furthermore, this novel gas sensor based on rGO reduced from pyrrole shows excellent responsive repeatability to NH3. Overall, the facile electrostatic self-assembly technique in aqueous solution facilitates device fabrication, the resultant self-assembled rGO-based sensing devices, with miniature, low-cost portable characteristics and outstanding sensing performances, which can ensure potential application in gas sensing fields.

  1. Bioanalytical and chemical sensors using living taste, olfactory, and neural cells and tissues: a short review.

    Science.gov (United States)

    Wu, Chunsheng; Lillehoj, Peter B; Wang, Ping

    2015-11-01

    Biosensors utilizing living tissues and cells have recently gained significant attention as functional devices for chemical sensing and biochemical analysis. These devices integrate biological components (i.e. single cells, cell networks, tissues) with micro-electro-mechanical systems (MEMS)-based sensors and transducers. Various types of cells and tissues derived from natural and bioengineered sources have been used as recognition and sensing elements, which are generally characterized by high sensitivity and specificity. This review summarizes the state of the art in tissue- and cell-based biosensing platforms with an emphasis on those using taste, olfactory, and neural cells and tissues. Many of these devices employ unique integration strategies and sensing schemes based on sensitive transducers including microelectrode arrays (MEAs), field effect transistors (FETs), and light-addressable potentiometric sensors (LAPSs). Several groups have coupled these hybrid biosensors with microfluidics which offers added benefits of small sample volumes and enhanced automation. While this technology is currently limited to lab settings due to the limited stability of living biological components, further research to enhance their robustness will enable these devices to be employed in field and clinical settings.

  2. Silicon-based optoelectronic integrated circuit for label-free bio/chemical sensor.

    Science.gov (United States)

    Song, Junfeng; Luo, Xianshu; Kee, Jack Sheng; Han, Kyungsup; Li, Chao; Park, Mi Kyoung; Tu, Xiaoguang; Zhang, Huijuan; Fang, Qing; Jia, Lianxi; Yoon, Yong-Jin; Liow, Tsung-Yang; Yu, Mingbin; Lo, Guo-Qiang

    2013-07-29

    We demonstrate a silicon-based optoelectronic integrated circuit (OEIC) for label-free bio/chemical sensing application. Such on-chip OEIC sensor system consists of optical grating couplers for vertical light coupling into silicon waveguides, a thermal-tunable microring as a tunable filter, an exposed microring as an optical label-free sensor, and a Ge photodetector for a direct electrical readout. Different from the conventional wavelength-scanning method, we adopt low-cost broadband ASE light source, together with the on-chip tunable filter to generate sliced light source. The effective refractive index change of the sensing microring induced by the sensing target is traced by scanning the supplied electrical power applied onto the tracing microring, and the detected electrical signal is read out by the Ge photodetector. For bulk refractive index sensing, we demonstrate using such OEIC sensing system with a sensitivity of ~15 mW/RIU and a detection limit of 3.9 μ-RIU, while for surface sensing of biotin-streptavidin, we obtain a surface mass sensitivity of S(m) = ~192 µW/ng·mm(-2) and a surface detection limit of 0.3 pg/mm(2). The presented OEIC sensing system is suitable for point-of-care applications.

  3. Characteristics and Mechanisms in Ion-Conducting Polymer Films as Chemical Sensors

    Energy Technology Data Exchange (ETDEWEB)

    HUGHES,ROBERT C.; YELTON,WILLIAM G.; PFEIFER,KENT B.; PATEL,SANJAY V.

    2000-07-12

    Solid Polymer Electrolytes (SPE) are widely used in batteries and fuel cells because of the high ionic conductivity that can be achieved at room temperature. The ions are usually Li or protons, although other ions can be shown to conduct in these polymer films. There has been very little published work on SPE films used as chemical sensors. The authors have found that thin films of polymers like polyethylene oxide (PEO) are very sensitive to low concentrations of volatile organic compounds (VOCs) such as common solvents. Evidence of a new sensing mechanism involving the percolation of ions through narrow channels of amorphous polymer is presented. They present impedance spectroscopy of PEO films in the frequency range 0.0001 Hz to 1 MHz for different concentrations of VOCs and relative humidity. They find that the measurement frequency is important for distinguishing ionic conductivity from the double layer capacitance and the parasitic capacitance.

  4. Novel semiconductor materials for the development of chemical sensors and biosensors: A review

    Energy Technology Data Exchange (ETDEWEB)

    Chaniotakis, Nikos [Laboratory of Analytical Chemistry, Department of Chemistry, University of Crete, Voutes 71003 Iraklion, Crete (Greece)], E-mail: nchan@chemistry.uoc.gr; Sofikiti, Nikoletta [Laboratory of Analytical Chemistry, Department of Chemistry, University of Crete, Voutes 71003 Iraklion, Crete (Greece)

    2008-05-12

    The aim of this manuscript is to provide a condensed overview of the contribution of certain relatively new semiconductor substrates in the development of chemical and biochemical field effect transistors. The silicon era is initially reviewed providing the background onto which the deployment of the new semiconductor materials for the development of bio-chem-FETs is based on. Subsequently emphasis is given to the selective interaction of novel semiconductor surfaces, including doped conductive diamond, gallium nitride, and indium nitride, with the analyte, and how this interaction can be properly transduced using semiconductor technology. The main advantages and drawbacks of these materials, as well as their future prospects for their applications in the sensor area are also described.

  5. Ionic liquids as green solvents and electrolytes for robust chemical sensor development.

    Science.gov (United States)

    Rehman, Abdul; Zeng, Xiangqun

    2012-10-16

    Ionic liquids (ILs) exhibit complex behavior. Their simultaneous dual nature as solvents and electrolytes supports the existence of structurally tunable cations and anions, which could provide the basis of a novel sensing technology. However, the elucidation of the physiochemical properties of ILs and their connections with the interaction and redox mechanisms of the target analytes requires concerted data acquired from techniques including spectroscopic investigations, thermodynamic and solvation models, and molecular simulations. Our laboratory is using these techniques for the rational design and selection of ILs and their composites that could serve as the recognition elements in various sensing platforms. ILs show equal utility in both piezoelectric and electrochemical formats through functionalized ionics that provide orthogonal chemo- and regioselectivity. In this Account, we summarize recent developments in and applications of task-specific ILs and their surface immobilization on solid supports. Such materials can serve as a replacement for conventional recognition elements and electrolytic media in piezoelectric and electrochemical sensing approaches, and we place a special focus on our contributions to these fields. ILs take advantage of both the physical and chemical forces of interaction and can incorporate various gas analytes. Exploiting these features, we have designed piezoelectric sensors and sensor arrays for high-temperature applications. Vibrational spectroscopy of these ILs reveals that hydrogen bonding and dipole-dipole interactions are typically responsible for the observed sensing profiles, but the polarization and cavity formation effect as an analyte approaches the recognition matrix can also cause selective discrimination. IL piezoelectric sensors can have low sensitivity and reproducibility. To address these issues, we designed IL/conducting polymer host systems that tune existing molecular templates with highly selective structure

  6. COMPARISON OF PERFORMANCE PIEZO RESONATORS BAW-TYPE TO CREATE CHEMICAL SENSOR

    Directory of Open Access Journals (Sweden)

    T. A. Kuchmenko

    2014-01-01

    Full Text Available Summary. Currently creation of small inexpensive analytical devices is very actual. Possibility of miniaturization vibrational gas sensors is associated with the possibility of using resonators smaller than the traditionally used sizes. The study used two types of sensors: sensors based on BAW resonators brand RK 169 with frequency of self-oscillation of 10 MHz and a mini - sensors, resonators based on BAW resonators brand MBC 10000 and MBC 15000 with frequencies of self-oscillation of 10 and 15 MHz respectively. As modifier of electrodes polyethylene glycol PEG 2000 was used. Check of sensitivity of microbalance and evaluation other performance properties of sensors was carried in pairs chloroform, 2-propanol and benzene. Mini -sensor has a smaller surface available sorption, whereby mini-sesors have a smaller analytical signal as compared traditional used resonators. Mass of coating which cause failure of self-oscillation for mini -sensors does not exceed 3 mcg and it is much smaller than for traditionally used sensors. It has been established that the analytical signal of mini-sensors in pairs of test compounds is higher than analytical signal of traditionally used sensors. Analytical signal is more for sensors with higher mass of coating and for sensors with higher selfoscillation frequency. The study found that the mini-sensors can be used for a narrow range of problems in the analysis. the sensitivity of mini-sensors is higher than that traditionally used sensors, but they have significant limitations on weight of coating.

  7. Analysis of viscous losses in the chemical interface layer of Love wave sensors.

    Science.gov (United States)

    Jakoby, B; Vellekoop, M J

    2000-01-01

    Love waves have been introduced as highly effective devices for liquid-sensing applications. For chemical sensors, a microacoustic delay line featuring a multilayered waveguide supporting a generalised Love wave mode can be used in an oscillator setup. The top layer of the waveguide is a chemical interface, which selectively adsorbs certain target molecules in the adjacent liquid. The increase in mass density caused by adsorption can be detected as changes in the oscillation frequency. Commonly used interface materials show viscoelastic losses leading to an unwanted damping of the wave. To keep the signal-to-noise ratio high, the total insertion loss of the delay line should be kept as low as possible. Furthermore, it must not exceed a certain value to allow the electronic circuitry to sustain the oscillation. We analyzed the viscoelastic losses, which strongly depend on the frequency being used. By means of the proposed theoretical approach, the maximum thickness of the interface layer can be determined not to exceed the losses that can be handled by the driving electronics.

  8. Smart chemical sensors using ZnO semiconducting thin films for freshness detection of foods and beverages

    Science.gov (United States)

    Nanto, Hidehito; Kobayashi, Toshiki; Dougami, Naganori; Habara, Masaaki; Yamamoto, Hajime; Kusano, Eiji; Kinbara, Akira; Douguchi, Yoshiteru

    1998-07-01

    The sensitivity of the chemical sensor, based on the resistance change of Al2O3-doped and SnO2-doped ZnO (ZnO:Al and ZnO:SnO2) thin film, is studied for exposure to various gases. It is found that the ZnO:Al and ZnO:Sn thin film chemical sensor has a high sensitivity and excellent selectivity for amine (TMA and DMA) gas and ethanol gas, respectively. The ZnO:Al (5.0 wt%) thin film chemical sensor which exhibit a high sensitivity for exposure to odors from rotten sea foods, such as salmon, sea bream, oyster, squid and sardine, responds to the freshness change of these sea foods. The ZnO:SnO2 (78 wt%) thin film chemical sensor which exhibit a high sensitivity for exposure to aroma from alcohols, such as wine, Japanese sake, and whisky, responds to the freshness change of these alcohols.

  9. Microwave assisted rapid growth of Mg(OH){sub 2} nanosheet networks for ethanol chemical sensor application

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hazmi, Faten [Department of Physics, College of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21569 (Saudi Arabia); Umar, Ahmad, E-mail: ahmadumar786@gmail.com [Promising Centre for Sensors and Electronic Devices (PCSED) and Centre for Advanced Materials and Nano-Research (CAMNR), Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Dar, G.N. [Promising Centre for Sensors and Electronic Devices (PCSED) and Centre for Advanced Materials and Nano-Research (CAMNR), Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Al-Ghamdi, A.A.; Al-Sayari, S.A. [Department of Physics, College of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21569 (Saudi Arabia); Al-Hajry, A. [Promising Centre for Sensors and Electronic Devices (PCSED) and Centre for Advanced Materials and Nano-Research (CAMNR), Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Department of Physics, College of Science and Arts, Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Kim, S.H. [Promising Centre for Sensors and Electronic Devices (PCSED) and Centre for Advanced Materials and Nano-Research (CAMNR), Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Al-Tuwirqi, Reem M. [Department of Physics, College of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21569 (Saudi Arabia); Alnowaiserb, Fowzia [Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); El-Tantawy, Farid [Department of Physics, Faculty of Science, Suez Canal University, Ismailia (Egypt)

    2012-04-05

    Highlights: Black-Right-Pointing-Pointer A facile microwave-assisted synthesis and characterizations of magnesium hydroxide (Mg(OH){sub 2}) nanosheet networks. Black-Right-Pointing-Pointer Fabrication of ethanol sensor based on (Mg(OH){sub 2}) nanosheet networks. Black-Right-Pointing-Pointer Good sensitivity ({approx}3.991 {mu}A cm{sup -2} mM{sup -1}) and lower detection limit (5 {mu}M). Black-Right-Pointing-Pointer This research opens a way to utilize Mg(OH){sub 2} nanostructures for chemical sensors applications. - Abstract: This paper reports a facile microwave-assisted synthesis of magnesium hydroxide (Mg(OH){sub 2}) nanosheet networks and their utilization for the fabrication of efficient ethanol chemical sensor. The synthesized nanosheets networks were characterized in terms of their morphological, structural and optical properties using various analysis techniques such as field emission scanning electron microscopy (FESEM), X-ray diffraction pattern (XRD), Fourier transform infrared (FTIR) and UV-Vis spectroscopy. The detailed morphological and structural investigations reveal that the synthesized (Mg(OH){sub 2}) products are nanosheet networks, grown in high density, and possessing hexagonal crystal structure. The optical band gap of as-synthesized Mg(OH){sub 2} nanosheet networks was examined by UV-Vis absorption spectrum, and found to be 5.76 eV. The synthesized nanosheet networks were used as supporting matrices for the fabrication of I-V technique based efficient ethanol chemical sensor. The fabricated ethanol sensor based on nanosheet networks exhibits good sensitivity ({approx}3.991 {mu}A cm{sup -2} mM{sup -1}) and lower detection limit (5 {mu}M), with linearity (R = 0.9925) in short response time (10.0 s). This work demonstrate that the simply synthesized Mg(OH){sub 2} nanosheet networks can effectively be used for the fabrication of efficient ethanol chemical sensors.

  10. Chemical Sensing Using Infrared Cavity Enhanced Spectroscopy: Short Wave Infrared Cavity Ring Down Spectroscopy (SWIR CRDS) Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Richard M.; Harper, Warren W.; Aker, Pam M.; Thompson, Jason S.; Stewart, Timothy L.

    2003-10-01

    The principal goal of Pacific Northwest National Laboratory's (PNNL's) Remote Spectroscopy Project is to explore and develop the science and technology behind point and stand off infrared (IR) spectroscopic chemical sensors that are needed for detecting weapons proliferation activity and countering terrorism. Missions addressed include detecting chemical, biological, and nuclear weapons and their production; counter terrorism measures that involve screening luggage, personnel, and shipping containers for explosives, firearms, narcotics, chemical weapons and/or their residues; and mapping of contaminated areas. The science and technology developed in this program is dual use in that it additionally supports progress in a diverse set of agendas that include chemical weapons defense programs, air operations activities, emissions monitoring, law enforcement, and medical diagnostics. Sensors for these missions require extremely low limits of detection because many of the targeted signature species are either present in low concentrations or have extremely low vapor pressures. The sensors also need to be highly selective as the environments that they will be operated in will contain a variety of interferent species and false positive detection is not an option. PNNL has been working on developing a class of sensors that draw vapor into optical cavities and use laser-based spectroscopy to identify and quantify the vapor chemical content. The cavity enhanced spectroscopies (CES) afford extreme sensitivity, excellent selectivity, noise immunity, and rapid, real-time, in-situ chemical characterization. PNNL's CES program is currently focused on developing two types of sensors. The first one, which is based on cavity ring down spectroscopy (CRDS), uses short wave infrared (SWIR) lasers to interrogate species. The second sensor, which is based on noise immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE OHMS), uses long wave infrared (LWIR

  11. Development Of Hot Surface Polysilicon-Based Chemical Sensor And Actuator With Integrated Catalytic Micropatterns For Gas Sensing Applications

    Science.gov (United States)

    Vereshchagina, E.; Gardeniers, J. G. E.

    2009-05-01

    Over the last twenty years, we have followed a rapid expansion in the development of chemical sensors and microreactors for detection and analysis of volatile organic compounds. However, for many of the developed gas sensors poor sensitivity and selectivity, and high-power consumption remain among one of the main drawbacks. One promising approach to increase selectivity at lower power consumption is calorimetric sensing, performed in a pulsed regime and using specific catalytic materials. In this work, we study kinetics of various catalytic oxidation reactions using micromachined hot surface polysilicon-based sensor containing sensitive and selective catalysts. The sensor acts as both thermal actuator of chemical and biochemical reactions on hot-surfaces and detector of heats (enthalpies) associated with these reactions. Using novel deposition techniques we integrated selective catalysts in an array of hot plates such that they can be thermally actuated and sensed individually. This allows selective detection and analysis of dangerous gas compounds in a mixture, specifically hydrocarbons at concentrations down to low ppm level. In this contribution we compare various techniques for the local immobilization of catalytic material on hot spots of the sensor in terms of process compatibility, mechanical stress, stability and cost.

  12. Chemical gas sensor application of open-pore mesoporous thin films based on integrated optical polarimetric interferometry.

    Science.gov (United States)

    Qi, Zhi-Mei; Honma, Itaru; Zhou, Haoshen

    2006-02-15

    Chemical gas sensors that employ integrated optical polarimetric interferometry were fabricated by the sol-gel synthesis of transparent mesoporous thin films of TiO2-P2O5 nanocomposite on tapered layers of TiO2 sputtered on tin-diffused glass waveguides. Atomic force microscopy images of the mesoporous thin film clearly show the open pore mouths on the film surface that favor rapid diffusion and adsorption of gas-phase analytes within the entire film. Adsorption of gas and vapor induces changes (Deltan) in the refractive index of the mesoporous thin film that lead to shifts in the phase difference between the fundamental transverse electric and magnetic modes simultaneously excited in the glass waveguide via single-beam incidence. Upon exposure to NH3 gas at concentrations as low as 100 ppb in dry air at room temperature, the sensor exhibits a reversible change in the phase difference with the response and recovery times of less than 60 and 90 s, respectively. It is unexpected that the sensor is unresponsive to either NO2 or C6H6 vapor, leading to a somewhat selective sensitivity to NH3. Determination of Deltan was carried out with a combination of the experimental results and the theoretical calculations. The sensor design represents a novel, effective, and easily accessible approach to mesoporous thin-film-based integrated optical chemical sensors.

  13. Fabrication of smart chemical sensors based on transition-doped-semiconductor nanostructure materials with µ-chips.

    Science.gov (United States)

    Rahman, Mohammed M; Khan, Sher Bahadar; Asiri, Abdullah M

    2014-01-01

    Transition metal doped semiconductor nanostructure materials (Sb2O3 doped ZnO microflowers, MFs) are deposited onto tiny µ-chip (surface area, ∼0.02217 cm(2)) to fabricate a smart chemical sensor for toxic ethanol in phosphate buffer solution (0.1 M PBS). The fabricated chemi-sensor is also exhibited higher sensitivity, large-dynamic concentration ranges, long-term stability, and improved electrochemical performances towards ethanol. The calibration plot is linear (r(2) = 0.9989) over the large ethanol concentration ranges (0.17 mM to 0.85 M). The sensitivity and detection limit is ∼5.845 µAcm(-2)mM(-1) and ∼0.11±0.02 mM (signal-to-noise ratio, at a SNR of 3) respectively. Here, doped MFs are prepared by a wet-chemical process using reducing agents in alkaline medium, which characterized by UV/vis., FT-IR, Raman, X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), and field-emission scanning electron microscopy (FE-SEM) etc. The fabricated ethanol chemical sensor using Sb2O3-ZnO MFs is simple, reliable, low-sample volume (<70.0 µL), easy of integration, high sensitivity, and excellent stability for the fabrication of efficient I-V sensors on μ-chips.

  14. Handheld multi-channel LAPS device as a transducer platform for possible biological and chemical multi-sensor applications

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Torsten [Aachen University of Applied Sciences, Juelich Campus, Institute of Nano- and Biotechnologies, Ginsterweg 1, 52428 Juelich (Germany); Institute of Bio- and Nanosystems (IBN-2), Research Centre Juelich GmbH, 52425 Juelich (Germany); Molina, Roberto [Aachen University of Applied Sciences, Juelich Campus, Institute of Nano- and Biotechnologies, Ginsterweg 1, 52428 Juelich (Germany); Yoshinobu, Tatsuo [Tohoku University, Department of Electronic Engineering, 6-6-05 Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Kloock, Joachim P. [Aachen University of Applied Sciences, Juelich Campus, Institute of Nano- and Biotechnologies, Ginsterweg 1, 52428 Juelich (Germany); Institute of Bio- and Nanosystems (IBN-2), Research Centre Juelich GmbH, 52425 Juelich (Germany); Biselli, Manfred; Canzoneri, Michelangelo; Schnitzler, Thomas [Aachen University of Applied Sciences, Juelich Campus, Institute of Nano- and Biotechnologies, Ginsterweg 1, 52428 Juelich (Germany); Schoening, Michael J. [Aachen University of Applied Sciences, Juelich Campus, Institute of Nano- and Biotechnologies, Ginsterweg 1, 52428 Juelich (Germany); Institute of Bio- and Nanosystems (IBN-2), Research Centre Juelich GmbH, 52425 Juelich (Germany)], E-mail: m.j.schoening@fz-juelich.de

    2007-12-01

    The light-addressable potentiometric sensor is a promising technology platform for multi-sensor applications and lab-on-chip devices. However, many prior LAPS developments suffer from their lack in terms of non-portability, insufficient robustness, complicate handling, etc. Hence, portable and robust LAPS-based measurement devices have been investigated by the authors recently. In this work, a 'chip card'-based light-addressable potentiometric sensor system is presented. The utilisation of ordinary 'chip cards' allows an easy handling of different sensor chips for a wide range of possible applications. The integration of the electronic and the mechanical set-up into a single reader unit results in a compact design with the benefits of portability and low required space. In addition, the presented work includes a new multi-frequency measurement procedure, based on an FFT algorithm, which enables the simultaneous real-time measurement of up to 16 sensor spots. The comparison between the former batch-LAPS and the new FFT-based LAPS set-up will be presented. The immobilisation of biological cells (CHO: Chinese hamster ovary) demonstrates the possibility to record their metabolic activity with 16 measurement spots on the same chip. Furthermore, a Cd{sup 2+}-selective chalcogenide-glass layer together with a pH-sensitive Ta{sub 2}O{sub 5} layer validates the use of the LAPS for chemical multi-sensor applications.

  15. Thin film chemical sensors based on chalcogenide glasses for ''electronic tongue'' application

    Energy Technology Data Exchange (ETDEWEB)

    Mourzina, Yu.; Legin, A.V.; Vlasov, Yu.G. [Sankt-Peterburgskij Univ., St. Petersburg (Russian Federation). Kafedra Khimii; Schoening, M.J. [Forschungszentrum Juelich GmbH (Germany). Abt. Sicherheit und Strahlenschutz]|[Univ. of Applied Sciences Aachen, Juelich (Germany); Schubert, J.; Zander, W.; Lueth, H. [Forschungszentrum Juelich GmbH (Germany). Abt. Sicherheit und Strahlenschutz

    2001-07-01

    A novel thin film preparation method, a pulsed laser deposition (PLD) technique, has been used in the present investigation to realise thin film chalcogenide layers for chemical sensor membranes. This technique is compatible with silicon technology and was aimed at fabrication of primary devices for analytical microsystems for the needs of fast analysis and in-situ measurements. The combination of the new type of the potentiometric thin film sensor array based on chalcogenide glass materials and artificial neural network for the experimental data processing is also presented. (orig.)

  16. Research on the Interaction of Hydrogen-Bond Acidic Polymer Sensitive Sensor Materials with Chemical Warfare Agents Simulants by Inverse Gas Chromatography

    OpenAIRE

    Liu Yang; Qiang Han; Shuya Cao; Feng Huang; Molin Qin; Chenghai Guo; Mingyu Ding

    2015-01-01

    Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant) and 2-CEES (a blister agent simulant) were used as probes. Chemical an...

  17. Surface properties of solids and surface acoustic waves: Application to chemical sensors and layer characterization

    Science.gov (United States)

    Krylov, V. V.

    1995-09-01

    A general phenomenological approach is given for the description of mechanical surface properties of solids and their influence on surface acoustic wave propogation. Surface properties under consideration may be changes of the stress distribution in subsurface atomic layers, the presence of adsorbed gas molecules, surface degradation as a result of impacts from an aggressive environment, damage due to mechanical manufacturing or polishing, deposition of thin films or liquid layers, surface corrugations, etc. If the characteristic thickness of the affected layers is much less than the wavelengths of the propagating surface waves, then the effects of all these irregularities can be described by means of non-classical boundary conditions incorporating the integral surface parameters such as surface tension, surface moduli of elasticity and surface mass density. The effect of surface properties on the propagation of Rayleigh surface waves is analysed in comparison with the results of traditional approaches, in particular with Auld's energy perturbation method. One of the important implications of the above-mentioned boudnary conditions is that they are adequate for the description of the effect of rarely distributed adsorbed atoms or molecules. This allows, in particular, to obtain a rigorous theoretical description of chemical sensors using surface acoustic waves and to derive analytical expressions for their sensitivity.

  18. Life cycle impacts and benefits of a carbon nanotube-enabled chemical gas sensor.

    Science.gov (United States)

    Gilbertson, Leanne M; Busnaina, Ahmed A; Isaacs, Jacqueline A; Zimmerman, Julie B; Eckelman, Matthew J

    2014-10-07

    As for any emerging technology, it is critical to assess potential life cycle impacts prior to widespread adoption to prevent future unintended consequences. The subject of this life cycle study is a carbon nanotube-enabled chemical gas sensor, which is a highly complex, low nanomaterial-concentration application with the potential to impart significant human health benefits upon implementation. Thus, the net lifecycle trade-offs are quantified using an impact-benefit ratio (IBR) approach proposed herein, where an IBR < 1 indicates that the downstream benefits outweigh the upstream impacts. The cradle-to-gate assessment results indicate that the midpoint impacts associated with producing CNTs are marginal compared with those associated with the other manufacturing stages. The cumulative upstream impacts are further aggregated to units of disability-adjusted life years (DALYs) using ReCiPe end point analysis method and quantitatively compared with the potential downstream DALY benefits, as lives saved, during the use phase. The approach presented in this study provides a guiding framework and quantitative method intended to encourage the development of nanoenabled products that have the potential to realize a net environmental, health, or societal benefit.

  19. Integrated optic chemical sensor for the simultaneous detection and quantification of multiple ions. Final report, March--September 1995

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza, E.

    1995-09-01

    This final report summarizes the work performed by Physical Optics Corporation (POC) on the DOE contract entitled {open_quotes}Integrated Optic Chemical Sensor for the Simultaneous Detection and Quantification of Multiple Metal Ions{close_quotes}. This project successfully demonstrated a multi-element integrated optic chemical sensor (IOCS) system capable of simultaneous detection and quantification of metal ions in a water flow stream. POC`s innovative integrated optic chemical sensor technology uses an array of chemically active optical waveguides integrated in parallel in a single small IOCS chip. The IOCS technique uses commonly available materials and straightforward processing to produce channel waveguides in porous glass, each channel treated with a chemical indicator that responds optically to heavy metal ions in a water flow stream. The porosity of the glass allows metal ions present in the water to diffuse into the glass and interact with the immobilized indicators, producing a measurable optical chance. For the {open_quotes}proof-of-concept{close_quotes} demonstration, POC designed and fabricated two types of IOCS chips. Type I uses an array of four straight channel waveguides, three of which are doped with a metal sensitive indicator, an ionophore. The undoped fourth channel is used as the reference channel. Type II uses a 1 x 4 star coupler structure with three sensing channels and a reference channel. Successful implementation of the IOCS technology is expected to have a broad impact on water quality control as well as in the commercial environmental monitoring market. Because of the self-referenced, multidetection capability of the IOCS technique, POC`s water quality sensors are expected to find markets in environmental monitoring and protection, ground water monitoring, and in-line process control. Specific applications include monitoring of chromium, copper, and iron ions in water discharged by the metal plating industry.

  20. Nanostructured Fiber Optic Cantilever Arrays and Hybrid MEMS Sensors for Chemical and Biological Detection Project

    Data.gov (United States)

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

  1. Metal oxide nanostructures synthesized on flexible and solid substrates and used for catalysts, UV detectors, and chemical sensors

    Science.gov (United States)

    Willander, Magnus; Sadollahkhani, Azar; Echresh, Ahmad; Nur, Omer

    2014-03-01

    In this paper we demonstrate the visibility of the low temperature chemical synthesis for developing device quality material grown on flexible and solid substrates. Both colorimetric sensors and UV photodetectors will be presented. The colorimetric sensors developed on paper were demonstrated for heavy metal detection, in particular for detecting copper ions in aqueous solutions. The demonstrated colorimetric copper ion sensors developed here are based on ZnO@ZnS core-shell nanoparticles (CSNPs). These sensors demonstrated an excellent low detection limit of less than 1 ppm of copper ions. Further the colorimetric sensors operate efficiently in a wide pH range between 4 and 11, and even in turbulent water. The CSNPs were additionally used as efficient photocatalytic degradation element and were found to be more efficient than pure ZnO nanoparticles (NPs). Also p-NiO/n-ZnO thin film/nanorods pn junctions were synthesized by a two-step synthesis process and were found to act as efficient UV photodetectors. Additionally we show the effect of the morphology of different CuO nanostructures on the efficiency of photo catalytic degradation of Congo red organic dye.

  2. Path to Impact for Autonomous Field Deployable Chemical Sensors: A Case Study of in Situ Nitrite Sensors.

    Science.gov (United States)

    Schierenbeck, Tim M; Smith, Matthew C

    2017-04-11

    Natural freshwater systems have been severely affected by excess loading of macronutrients (e.g., nitrogen and phosphorus) from fertilizers, fossil fuels, and human and livestock waste. In the USA, impacts to drinking water quality, biogeochemical cycles, and aquatic ecosystems are estimated to cost US$210 billion annually. Field-deployable nutrient sensors (FDS) offer potential to support research and resource management efforts by acquiring higher resolution data than are currently supported by expensive conventional sampling methods. Following nearly 40 years of research and development, FDS instruments are now starting to penetrate commercial markets. However, instrument uncertainty factors (high cost, reliability, accuracy, and precision) are key drivers impeding the uptake of FDS by the majority of users. Using nitrite sensors as a case study, we review the trends, opportunities, and challenges in producing and implementing FDS from a perspective of innovation and impact. We characterize the user community and consumer needs, identify trends in research approaches, tabulate state-of-the-art examples and specifications, and discuss data life cycle considerations. With further development of FDS through prototyping and testing in real-world applications, these tools can deliver information for protecting and restoring natural waters, enhancing process control for industrial operations and water treatment, and providing novel research insights.

  3. Cantilever-based bio-chemical sensor integrated in a microliquid handling system

    DEFF Research Database (Denmark)

    Thaysen, Jacob; Marie, Rodolphe; Boisen, Anja

    2001-01-01

    The cantilevers have integrated piezoresistive readout which, compared to optical readout, enables simple measurements on even non-transparent liquids, such as blood. First, we introduce a simple theory for using piezoresistive cantilevers as surface stress sensors. Then, the sensor fabrication b...

  4. Low power silicon-based thermal sensors and actuators for chemical applications

    NARCIS (Netherlands)

    Vereshchagina, Elizaveta

    2011-01-01

    In the Hot Silicon project low and ultra-low-power Si-based hot surface devices have been developed, i.e. thermal sensors and actuators, for application in catalytic gas micro sensors, micro- and nano- calorimeters. This work include several scientific and technological aspects: • Design and fabrica

  5. Theoretical investigation of conductivity sensitivities of SiC-based bio-chemical acoustic wave sensors

    Science.gov (United States)

    Fan, Li; Chen, Zhe; Zhang, Shu-yi; Zhang, Hui

    2014-02-01

    The phase velocities, electromechanical coupling coefficients, conductivity sensitivities, insert losses, and minimum detectable masses of Rayleigh and Lamb waves sensors based on silicon carbide (SiC) substrates are theoretically studied. The results are compared with the performances of the sensors based on conventional silicon substrates. It is found that the sensors using SiC substrates have higher electromechanical coupling coefficients and conductivity sensitivities than the conventional silicon-based sensors in virtue of piezoelectricity of the SiC. Moreover, higher phase velocities in SiC substrates can reduce the insert losses and minimum detectable masses of the sensors. In this case, in the detection of the gas with the tiny mass as the hydrogen, in which the conductivity sensitivity is more important than the mass sensitivity, the sensor based on the SiC substrate has a higher sensitivity and exhibits the potential to detect the gas with the concentration below the ppm level. According to the results, the performances of the sensors based on the Rayleigh and Lamb waves using the SiC substrates can be optimized by properly selecting piezoelectric films, structural parameters, and operating wavelengths.

  6. Opto-chemical sensors based on integrated ring-shaped organic photodiodes: progress and applications

    Science.gov (United States)

    Mayr, Torsten; Abel, Tobias; Ungerböck, Birgit; Sagmeister, Martin; Charwat, Verena; Ertl, Peter; Kraker, Elke; Köstler, Stefan; Tschepp, Andreas; Lamprecht, Bernhard

    2012-10-01

    The recent advances on a monolithically integrated sensor platform based on ring-shaped organic photo detectors are presented. Various sensing chemistries based on luminescence for the detection of a number of parameters such as oxygen, carbon dioxide, humidity and pH in gaseous and/or liquid phase were investigated and optimized to the requirements of the sensor platform. Aiming on practical application, the need and methods to reference luminescence signals are evaluated including two wavelength rationing and lifetime measurements. Finally, we will discuss potential applications of the platform and present a micro-fluidic chip containing an array of integrated sensor spots and organic photodiodes.

  7. Sol-gels with fiber-optic chemical sensor potential: Effects of preparation, aging, and long-term storage

    Science.gov (United States)

    Badini, G. E.; Grattan, K. T. V.; Tseung, A. C. C.

    1995-08-01

    The features of sol-gels, incorporating pH-sensitive dyes, designed as potential substrates for fiber-optic chemical sensors, have been investigated in terms of a variety of characteristics resulting from the preparation methods used and following the storage of samples for a period of several years. These materials, organically doped sol-gels, have been used as the heart of a number of prototype chemical sensing instruments, and a key issue in their effective use in instrumentation is their long-term durability and stability. In this work, it has been shown that such aged gel substrates can withstand immersion in water, drying, and reimmersion without fragmenting. Such impregnated gels were shown to still exhibit strong fluorescence, although some changes to the gel structure, determined from microhardness measurements, were observed and reported, reflecting their potential for use in chemically sensitive fiber optic-based instruments.

  8. A Molecularly Imprinted Polymer (MIP)-Coated Microbeam MEMS Sensor for Chemical Detection

    Science.gov (United States)

    2015-09-01

    microelectromechanical systems (MEMS)- based gas sensor. The sensor was characterized by parametric bifurcation noise- based tracking. 15. SUBJECT TERMS Molecular ...template molecule in size, shape, and functionality. Essentially, one creates a molecular “ memory ” within the imprinted polymer matrix. This allows...SUPPLEMENTARY NOTES A reprint from Proc. of SPIE Vol. 9455 94550W-1. 14. ABSTRACT Recently, microcantilever- based technology has emerged as a viable sensing

  9. Intrinsic Fiber Optic Chemical Sensors for Subsurface Detection of CO2

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, Jesus [Intelligent Optical Systems, Inc., Torrance, CA (United States)

    2016-01-01

    Intelligent Optical Systems, Inc. has developed distributed intrinsic fiber optic sensors to directly quantify the concentration of dissolved or gas-phase CO2 for leak detection or plume migration in carbon capture and sequestration (CCS). The capability of the sensor for highly sensitive detection of CO2 in the pressure and temperature range of 15 to 2,000 psi and 25°C to 175°C was demonstrated, as was the capability of operating in highly corrosive and contaminated environments such as those often found in CO2 injection sites. The novel sensor system was for the first time demonstrated deployed in a deep well, detecting multiple CO2 releases, in real time, at varying depths. Early CO2 release detection, by means of a sensor cable integrating multiple sensor segments, was demonstrated, as was the capability of quantifying the leak. The novel fiber optic sensor system exhibits capabilities not achieved by any other monitoring technology. This project represents a breakthrough in monitoring capabilities for CCS applications.

  10. Optical fiber chemical sensors with sol-gel derived nanomaterials for monitoring high temperature/high pressure reactions in clean energy technologies

    Science.gov (United States)

    Tao, Shiquan

    2010-04-01

    The development of sensor technologies for in situ, real time monitoring the high temperature/high pressure (HTP) chemical processes used in clean energy technologies is a tough challenge, due to the HTP, high dust and corrosive chemical environment of the reaction systems. A silica optical fiber is corrosive resistance, and can work in HTP conditions. This paper presents our effort in developing fiber optic sensors for in situ, real time monitoring the concentration of trace ammonia and hydrogen in high temperature gas samples. Preliminary test results illustrate the feasibility of using fiber optic sensor technologies for monitoring HTP processes for next generation energy industry.

  11. Identifying Rhodamine Dye Plume Sources in Near-Shore Oceanic Environments by Integration of Chemical and Visual Sensors

    Directory of Open Access Journals (Sweden)

    Jiangchen Yu

    2013-03-01

    Full Text Available This article presents a strategy for identifying the source location of a chemical plume in near-shore oceanic environments where the plume is developed under the influence of turbulence, tides and waves. This strategy includes two modules: source declaration (or identification and source verification embedded in a subsumption architecture. Algorithms for source identification are derived from the moth-inspired plume tracing strategies based on a chemical sensor. The in-water test missions, conducted in November 2002 at San Clemente Island (California, USA in June 2003 in Duck (North Carolina, USA and in October 2010 at Dalian Bay (China, successfully identified the source locations after autonomous underwater vehicles tracked the rhodamine dye plumes with a significant meander over 100 meters. The objective of the verification module is to verify the declared plume source using a visual sensor. Because images taken in near shore oceanic environments are very vague and colors in the images are not well-defined, we adopt a fuzzy color extractor to segment the color components and recognize the chemical plume and its source by measuring color similarity. The source verification module is tested by images taken during the CPT missions.

  12. Handheld and mobile hyperspectral imaging sensors for wide-area standoff detection of explosives and chemical warfare agents

    Science.gov (United States)

    Gomer, Nathaniel R.; Gardner, Charles W.; Nelson, Matthew P.

    2016-05-01

    Hyperspectral imaging (HSI) is a valuable tool for the investigation and analysis of targets in complex background with a high degree of autonomy. HSI is beneficial for the detection of threat materials on environmental surfaces, where the concentration of the target of interest is often very low and is typically found within complex scenery. Two HSI techniques that have proven to be valuable are Raman and shortwave infrared (SWIR) HSI. Unfortunately, current generation HSI systems have numerous size, weight, and power (SWaP) limitations that make their potential integration onto a handheld or field portable platform difficult. The systems that are field-portable do so by sacrificing system performance, typically by providing an inefficient area search rate, requiring close proximity to the target for screening, and/or eliminating the potential to conduct real-time measurements. To address these shortcomings, ChemImage Sensor Systems (CISS) is developing a variety of wide-field hyperspectral imaging systems. Raman HSI sensors are being developed to overcome two obstacles present in standard Raman detection systems: slow area search rate (due to small laser spot sizes) and lack of eye-safety. SWIR HSI sensors have been integrated into mobile, robot based platforms and handheld variants for the detection of explosives and chemical warfare agents (CWAs). In addition, the fusion of these two technologies into a single system has shown the feasibility of using both techniques concurrently to provide higher probability of detection and lower false alarm rates. This paper will provide background on Raman and SWIR HSI, discuss the applications for these techniques, and provide an overview of novel CISS HSI sensors focused on sensor design and detection results.

  13. Nanowire Chemical/Biological Sensors: Status and a Roadmap for the Future.

    Science.gov (United States)

    Fennell, John F; Liu, Sophie F; Azzarelli, Joseph M; Weis, Jonathan G; Rochat, Sébastien; Mirica, Katherine A; Ravnsbæk, Jens B; Swager, Timothy M

    2016-01-22

    Chemiresistive sensors are becoming increasingly important as they offer an inexpensive option to conventional analytical instrumentation, they can be readily integrated into electronic devices, and they have low power requirements. Nanowires (NWs) are a major theme in chemosensor development. High surface area, interwire junctions, and restricted conduction pathways give intrinsically high sensitivity and new mechanisms to transduce the binding or action of analytes. This Review details the status of NW chemosensors with selected examples from the literature. We begin by proposing a principle for understanding electrical transport and transduction mechanisms in NW sensors. Next, we offer the reader a review of device performance parameters. Then, we consider the different NW types followed by a summary of NW assembly and different device platform architectures. Subsequently, we discuss NW functionalization strategies. Finally, we propose future developments in NW sensing to address selectivity, sensor drift, sensitivity, response analysis, and emerging applications.

  14. Ram-air sample collection device for a chemical warfare agent sensor

    Science.gov (United States)

    Megerle, Clifford A.; Adkins, Douglas R.; Frye-Mason, Gregory C.

    2002-01-01

    In a surface acoustic wave sensor mounted within a body, the sensor having a surface acoustic wave array detector and a micro-fabricated sample preconcentrator exposed on a surface of the body, an apparatus for collecting air for the sensor, comprising a housing operatively arranged to mount atop the body, the housing including a multi-stage channel having an inlet and an outlet, the channel having a first stage having a first height and width proximate the inlet, a second stage having a second lower height and width proximate the micro-fabricated sample preconcentrator, a third stage having a still lower third height and width proximate the surface acoustic wave array detector, and a fourth stage having a fourth height and width proximate the outlet, where the fourth height and width are substantially the same as the first height and width.

  15. Research on the Interaction of Hydrogen-Bond Acidic Polymer Sensitive Sensor Materials with Chemical Warfare Agents Simulants by Inverse Gas Chromatography

    Directory of Open Access Journals (Sweden)

    Liu Yang

    2015-06-01

    Full Text Available Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant and 2-CEES (a blister agent simulant were used as probes. Chemical and physical parameters such as heats of absorption and Henry constants of the polymers to DMMP and 2-CEES were determined by inverse gas chromatography. Details concerning absorption performance are also discussed in this paper.

  16. Research on the interaction of hydrogen-bond acidic polymer sensitive sensor materials with chemical warfare agents simulants by inverse gas chromatography.

    Science.gov (United States)

    Yang, Liu; Han, Qiang; Cao, Shuya; Huang, Feng; Qin, Molin; Guo, Chenghai; Ding, Mingyu

    2015-06-02

    Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant) and 2-CEES (a blister agent simulant) were used as probes. Chemical and physical parameters such as heats of absorption and Henry constants of the polymers to DMMP and 2-CEES were determined by inverse gas chromatography. Details concerning absorption performance are also discussed in this paper.

  17. Low-Power, Antifuse-Based Silicon Chemical Sensor on a Suspended Membrane

    NARCIS (Netherlands)

    Kovalgin, A.Y.; Holleman, J.; Iordache, G.; Jenneboer, T.; Falke, F.; Zieren, V.; Goossens, M.J.

    2006-01-01

    In this paper we describe a new, simple, and cheap silicon sensor operating at a high temperature of about 1000 K and consuming a very low power of a few milliwatts. We developed a silicon-processing compatible, simple, and low-cost method for processing thermally isolated suspended membranes. This

  18. Development and characterization of electrochemical cantilever sensor for bio/chemical sensing applications

    DEFF Research Database (Denmark)

    Quan, Xueling; Fischer, Lee MacKenzie; Boisen, Anja

    2011-01-01

    We report the improvements made to our previously developed electrochemical cantilever (EC) sensor, where nanoporous gold material is employed as working electrodes in microcantilever arrays, while combined counter-reference electrodes are integrated on the chip. For a surface stress change of 1m...

  19. CRIM-TRACK: Sensor System for Detection of Criminal Chemical Substances

    DEFF Research Database (Denmark)

    Munk, Jens Kristian; Buus, Ole Thomsen; Larsen, Jan;

    2015-01-01

    and precursors thereof in laboratory settings. Using colorimetric technology we have developed prototypes that employ disposable sensing chips. Ease of operation and intuitive sensor response are highly prioritized features that we implement as we gather data to feed into machine learning. With machine learning...

  20. Bendable Electro-chemical Lactate Sensor Printed with Silver Nano-particles

    Science.gov (United States)

    Abrar, Md Abu; Dong, Yue; Lee, Paul Kyuheon; Kim, Woo Soo

    2016-07-01

    Here we report a flexible amperometric lactate biosensor using silver nanoparticle based conductive electrode. Mechanically bendable cross-serpentine-shaped silver electrode is generated on flexible substrate for the mechanical durability such as bending. The biosensor is designed and fabricated by modifying silver electrode with lactate oxidase immobilized by bovine serum albumin. The in-sensor pseudo Ag/AgCl reference electrode is fabricated by chloridization of silver electrode, which evinced its long-term potential stability against a standard commercial Ag/AgCl reference electrode. The amperometric response of the sensor shows linear dependence with lactate concentration of 1~25 mM/L. Anionic selectivity is achieved by using drop-casted Nafion coated on silver electrode against anionic interferences such as ascorbate. This non-invasive electrochemical lactate sensor also demonstrates excellent resiliency against mechanical deformation and temperature fluctuation which leads the possibility of using it on human epidermis for continuous measurement of lactate from sweat. Near field communication based wireless data transmission is demonstrated to reflect a practical approach of the sensor to measure lactate concentration portably using human perspiration.

  1. Fiber Optic-Fluorescence Sensors for Remote Detection of Chemical Species in Seawater

    Science.gov (United States)

    1989-09-01

    from the viewing volume by diffusive/convective mass transport processes and replaced by uncomplexed indicator from the reservoir. Because the flow...Morin as Fluorescence sensor for Determination of Aluminum(III) ." Anal. Chem., 1983, 55, 667-670. (10) Urbano , E., H. Offenbacher, and O.S. Wolfbeis

  2. Combining Non Selective Gas Sensors on a Mobile Robot for Identification and Mapping of Multiple Chemical Compounds

    Directory of Open Access Journals (Sweden)

    Victor Hernandez Bennetts

    2014-09-01

    Full Text Available In this paper, we address the task of gas distribution modeling in scenarios where multiple heterogeneous compounds are present. Gas distribution modeling is particularly useful in emission monitoring applications where spatial representations of the gaseous patches can be used to identify emission hot spots. In realistic environments, the presence of multiple chemicals is expected and therefore, gas discrimination has to be incorporated in the modeling process. The approach presented in this work addresses the task of gas distribution modeling by combining different non selective gas sensors. Gas discrimination is addressed with an open sampling system, composed by an array of metal oxide sensors and a probabilistic algorithm tailored to uncontrolled environments. For each of the identified compounds, the mapping algorithm generates a calibrated gas distribution model using the classification uncertainty and the concentration readings acquired with a photo ionization detector. The meta parameters of the proposed modeling algorithm are automatically learned from the data. The approach was validated with a gas sensitive robot patrolling outdoor and indoor scenarios, where two different chemicals were released simultaneously. The experimental results show that the generated multi compound maps can be used to accurately predict the location of emitting gas sources.

  3. Combining non selective gas sensors on a mobile robot for identification and mapping of multiple chemical compounds.

    Science.gov (United States)

    Bennetts, Victor Hernandez; Schaffernicht, Erik; Pomareda, Victor; Lilienthal, Achim J; Marco, Santiago; Trincavelli, Marco

    2014-09-17

    In this paper, we address the task of gas distribution modeling in scenarios where multiple heterogeneous compounds are present. Gas distribution modeling is particularly useful in emission monitoring applications where spatial representations of the gaseous patches can be used to identify emission hot spots. In realistic environments, the presence of multiple chemicals is expected and therefore, gas discrimination has to be incorporated in the modeling process. The approach presented in this work addresses the task of gas distribution modeling by combining different non selective gas sensors. Gas discrimination is addressed with an open sampling system, composed by an array of metal oxide sensors and a probabilistic algorithm tailored to uncontrolled environments. For each of the identified compounds, the mapping algorithm generates a calibrated gas distribution model using the classification uncertainty and the concentration readings acquired with a photo ionization detector. The meta parameters of the proposed modeling algorithm are automatically learned from the data. The approach was validated with a gas sensitive robot patrolling outdoor and indoor scenarios, where two different chemicals were released simultaneously. The experimental results show that the generated multi compound maps can be used to accurately predict the location of emitting gas sources.

  4. Rhythmic chemical reaction of CO on the surface of a SnO 2 gas sensor

    Science.gov (United States)

    Nakata, S.; Kato, Y.; Kaneda, Y.; Yoshikawa, K.

    1996-12-01

    The oscillatory phenomenon of the oxidative reaction of CO on an n-type semiconductor surface is reported. As a semiconductor, we used a SnO 2 gas sensor, which is widely used for practical application. Various characteristics in the time series of the conductance were observed and analyzed with next amplitude mapping and Fourier power spectra. The simultaneous measurement of the temperature on the semiconductor surface and the conductance suggested that the temperature change was a key variable in the oscillatory phenomenon. As a preliminary theoretical model, a simulation was performed using the surface concentration of CO and the temperature as two independent variables. The present study is part of our attempt to use a time-dependent nonlinear response for the development of an intelligent sensor which mimics sensory mechanisms in living organisms.

  5. The Present State of Amperometric Nanowire Sensors for Chemical and Biological Detection

    Science.gov (United States)

    2006-10-01

    can also be used to reset the sensor by desorbing the bound species and releasing charge trapped at the interfaces which causes hysteresis (5, 17...susceptible to surface chemistry and can result in long term stability issues. Trapped charges may produce hysteresis effects. Adsorbed...Functional Materials 2004, 14 (10), 943–956. 9. Wang, X. D.; Summers, C. J.; Wang, Z. L. Mesoporous single-crystal ZnO nanowires epitaxially sheathed with

  6. Literature search, review, and compilation of data for chemical and radiochemical sensors: Task 1 report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-01-01

    During the next several decades, the US Department of Energy is expected to spend tens of billions of dollars in the characterization, cleanup, and monitoring of DOE`s current and former installations that have various degrees of soil and groundwater contamination made up of both hazardous and mixed wastes. Each of these phases will require site surveys to determine type and quantity of hazardous and mixed wastes. It is generally recognized that these required survey and monitoring efforts cannot be performed using traditional chemistry methods based on laboratory evaluation of samples from the field. For that reason, a tremendous push during the past decade or so has been made on research and development of sensors. This report contains the results of an extensive literature search on sensors that are used or have applicability in environmental and waste management. While restricting the search to a relatively small part of the total chemistry spectrum, a sizable body of reference material is included. Results are presented in tabular form for general references obtained from data base searches, as narrative reviews of relevant chapters from proceedings, as book reviews, and as reviews of journal articles with particular relevance to the review. Four broad sensor types are covered: electrochemical processes, piezoelectric devices, fiber optics, and radiochemical processes. The topics of surface chemistry processes and biosensors are not treated separately because they often are an adjunct to one of the four sensors listed. About 1,000 tabular entries are listed, including selected journal articles, reviews of conference/meeting proceedings, and books. Literature to about mid-1992 is covered.

  7. Fabrication of optical chemical ammonia sensors using anodized alumina supports and sol-gel method.

    Science.gov (United States)

    Markovics, Akos; Kovács, Barna

    2013-05-15

    In this comparative study, the fabrication and the sensing properties of various reflectometric optical ammonia gas sensors are described. In the first set of experiments the role of the support material was investigated on four different sensor membranes. Two of them were prepared by the adsorption of bromocresol green indicator on anodized aluminum plates. The applied anodizing voltages were 12 V and 24 V, which resulted in different dynamic ranges and response times for gaseous ammonia. The sol-gel method was used for the preparation of the other batch of sensors. These layers were coated on anodized aluminum plates (24 V) and on standard microscope cover glasses. In spite of the identical sensing chemistry, slightly different response times were measured merely because of the aluminum surface porosity. Gas molecules can remain entrapped in the pores, which results in delayed recovery time. On the other hand, the porous oxide film provides excellent adhesion, making the anodized aluminum an attractive support for the sol-gel layer.

  8. Preparation,inentification and application of pyrenebutyric acid-silica and diphenylanthracene-silica reagent on fiber-optic chemical sensor

    Institute of Scientific and Technical Information of China (English)

    LI Xin-xia; CHEN Jian

    2003-01-01

    @@ 1 Introduction Two new fiber-optic chemical sensor based on multiple fluorescence quenching is described. The reagent phases of the sensors are stable in organic solvent. The first reagent phase was constructed by covalent bonding pyrenebutyric acid (PBA) to the surface of glass (PBA-SiO2). It was identified by IR spectrum, fluorescence spectra and TGA analysis. And it can determine Rutin in ethanol.

  9. A Method for Integrating ZnO Coated Nanosprings into a Low Cost Redox-Based Chemical Sensor and Catalytic Tool for Determining Gas Phase Reaction Kinetics

    Directory of Open Access Journals (Sweden)

    Pavel V. Bakharev

    2014-01-01

    Full Text Available A chemical sensor (chemiresistor was constructed from a xenon light bulb by coating it with a 3-D zinc oxide coated silica nanospring mat, where the xenon light bulb serves as the sensor heater. The sensor response to toluene as a function of xenon light bulb sensor temperature (TLB and vapor temperature (TV was observed and analyzed. The optimum operational parameters in terms of TLB and TV were determined to be 435 °C and 250 °C, respectively. The activation energy of toluene oxidation (Ed on the ZnO surface was determined to be 87 kJ·mol−1, while the activation energy of oxidation (Ea of the depleted ZnO surface was determined to be 83 kJ·mol−1. This study serves as proof of principle for integrating nanomaterials into an inexpensive sensor platform, which can also be used to characterize gas-solid, or vapor-solid, redox processes.

  10. Design, Fabrication, Processing, and Testing of Micro-Electro-Mechanical Chemical Sensors

    Science.gov (United States)

    1995-12-01

    3.2.2 Electrostatic Theory. .. .. .. .. ... ... ... .... .. 48 3.2.3 Capacitance . .. .. .. .. ... ... .... ... ... .... 50 3.3 Chemical Transport Theory...available to heat the thin film coating, effecting both an intrinsic conductivity change due to the semiconducting material and an extrinsic change due to...other surface-fabricated MOSFET device, except that the metal gate is replaced by an external reference electrode and is coated with a chemically

  11. CRIM-TRACK: sensor system for detection of criminal chemical substances

    Science.gov (United States)

    Munk, Jens K.; Buus, Ole T.; Larsen, Jan; Dossi, Eleftheria; Tatlow, Sol; Lässig, Lina; Sandström, Lars; Jakobsen, Mogens H.

    2015-10-01

    Detection of illegal compounds requires a reliable, selective and sensitive detection device. The successful device features automated target acquisition, identification and signal processing. It is portable, fast, user friendly, sensitive, specific, and cost efficient. LEAs are in need of such technology. CRIM-TRACK is developing a sensing device based on these requirements. We engage highly skilled specialists from research institutions, industry, SMEs and LEAs and rely on a team of end users to benefit maximally from our prototypes. Currently we can detect minute quantities of drugs, explosives and precursors thereof in laboratory settings. Using colorimetric technology we have developed prototypes that employ disposable sensing chips. Ease of operation and intuitive sensor response are highly prioritized features that we implement as we gather data to feed into machine learning. With machine learning our ability to detect threat compounds amidst harmless substances improves. Different end users prefer their equipment optimized for their specific field. In an explosives-detecting scenario, the end user may prefer false positives over false negatives, while the opposite may be true in a drug-detecting scenario. Such decisions will be programmed to match user preference. Sensor output can be as detailed as the sensor allows. The user can be informed of the statistics behind the detection, identities of all detected substances, and quantities thereof. The response can also be simplified to "yes" vs. "no". The technology under development in CRIM-TRACK will provide custom officers, police and other authorities with an effective tool to control trafficking of illegal drugs and drug precursors.

  12. Chemical detection in liquid media with a refractometric sensor based on a multimode optical fibre

    OpenAIRE

    V. Matejec; Jaffrezic-Renault, N.; Abdelghani, A.; S. Hleli; Cherif, K

    2002-01-01

    In this paper the physical basis for the design of an optical fibre sensor suited for aqueous medium and gas phase based on the excitation of an evanescent wave at the core/cladding interface is developed. The detection based on the refractive index changes (between 1.41 and 1.45) of the infinite dielectric medium which can be an electrolyte or a sol-gel polymer deposited on the uncladed part of the fibre. Refractive indices of absorbent and volatile compounds such as fuel and unleaded gas we...

  13. IN-SITU IONIC CHEMICAL ANALYSIS OF FRESH WATER VIA A NOVEL COMBINED MULTI-SENSOR / SIGNAL PROCESSING ARCHITECTURE

    Science.gov (United States)

    Mueller, A. V.; Hemond, H.

    2009-12-01

    The capability for comprehensive, real-time, in-situ characterization of the chemical constituents of natural waters is a powerful tool for the advancement of the ecological and geochemical sciences, e.g. by facilitating rapid high-resolution adaptive sampling campaigns and avoiding the potential errors and high costs related to traditional grab sample collection, transportation and analysis. Portable field-ready instrumentation also promotes the goals of large-scale monitoring networks, such as CUASHI and WATERS, without the financial and human resources overhead required for traditional sampling at this scale. Problems of environmental remediation and monitoring of industrial waste waters would additionally benefit from such instrumental capacity. In-situ measurement of all major ions contributing to the charge makeup of natural fresh water is thus pursued via a combined multi-sensor/multivariate signal processing architecture. The instrument is based primarily on commercial electrochemical sensors, e.g. ion selective electrodes (ISEs) and ion selective field-effect transistors (ISFETs), to promote low cost as well as easy maintenance and reproduction,. The system employs a novel architecture of multivariate signal processing to extract accurate information from in-situ data streams via an "unmixing" process that accounts for sensor non-linearities at low concentrations, as well as sensor cross-reactivities. Conductivity, charge neutrality and temperature are applied as additional mathematical constraints on the chemical state of the system. Including such non-ionic information assists in obtaining accurate and useful calibrations even in the non-linear portion of the sensor response curves, and measurements can be made without the traditionally-required standard additions or ionic strength adjustment. Initial work demonstrates the effectiveness of this methodology at predicting inorganic cations (Na+, NH4+, H+, Ca2+, and K+) in a simplified system containing

  14. An optical chemical sensor for thorium (IV) determination based on thorin.

    Science.gov (United States)

    Rastegarzadeh, S; Pourreza, N; Saeedi, I

    2010-01-15

    A selective method for the determination of thorium (IV) using an optical sensor is described. The sensing membrane is prepared by immobilization of thorin-methyltrioctylammonium ion pair on triacetylcellulose polymer. The sensor produced a linear response for thorium (IV) concentration in the range of 6.46 x 10(-6) to 9.91 x 10(-5)mol L(-1) with detection limit of 1.85 x 10(-6)mol L(-1). The regeneration of optode was accomplished completely at a short time (less than 20s) with 0.1 mol L(-1) of oxalate ion solution. The relative standard deviation for ten replicate measurements of 2.15 x 10(-5) and 8.62 x 10(-5)mol L(-1) of thorium was 2.71 and 1.65%, respectively. The optode membrane exhibits good selectivity for thorium (IV) over several other ionic species and are comparable to those obtained in case of spectrophotometric determination of thorium using thorin in solution. A good agreement with the ICP-MS and spiked method was achieved when the proposed optode was applied to the determination of thorium (IV) in dust and water samples.

  15. Chemically synthesized PbS Nano particulate thin films for a rapid NO2 gas sensor

    Directory of Open Access Journals (Sweden)

    Burungale Vishal V.

    2016-03-01

    Full Text Available Rapid NO2 gas sensor has been developed based on PbS nanoparticulate thin films synthesized by Successive Ionic Layer Adsorption and Reaction (SILAR method at different precursor concentrations. The structural and morphological properties were investigated by means of X-ray diffraction and field emission scanning electron microscope. NO2 gas sensing properties of PbS thin films deposited at different concentrations were tested. PbS film with 0.25 M precursor concentration showed the highest sensitivity. In order to optimize the operating temperature, the sensitivity of the sensor to 50 ppm NO2 gas was measured at different operating temperatures, from 50 to 200 °C. The gas sensitivity increased with an increase in operating temperature and achieved the maximum value at 150 °C, followed by a decrease in sensitivity with further increase of the operating temperature. The sensitivity was about 35 % for 50 ppm NO2 at 150 °C with rapid response time of 6 s. T90 and T10 recovery time was 97 s at this gas concentration.

  16. A miniature photoelectrochemical sensor based on organic electrochemical transistor for sensitive determination of chemical oxygen demand in wastewaters.

    Science.gov (United States)

    Liao, Jianjun; Lin, Shiwei; Zeng, Min; Yang, Yue

    2016-05-01

    A three-electrode configuration is often required in the conventional photoelectrochemical measurements. Nevertheless, one common drawback is the reference electrode and the counter electrode used in the measurements, which has been proved to be an impediment for the miniaturization. In this study, a simple, cost-effective and miniature photoelectrochemical sensor based on high sensitive organic electrochemical transistor (OECT) is developed and used for the determination of chemical oxygen demand (COD) in wastewaters. The devices show detection limit down to 0.01 mg/L COD, which is two orders of magnitude better than that of the conventional photoelectrochemical method. The excellent sensing performance can be contributed to the novel sensing mechanism of OECT devices. That is, the devices are sensitive to the potential changes induced by the photoelectrochemical reaction on TiO2 nanotube arrays gate electrodes. Real sample analyses are also carried out. The results demonstrate that the measured COD values using the OECT devices and the standard dichromate methods are in a good agreement. Since the proposed sensor is constructed on a miniature transistor, it is expected that the device shows a promising application on the integrated COD monitoring platform.

  17. Sensitive and fast response ethanol chemical sensor based on as-grown Gd2O3 nanostructures

    Institute of Scientific and Technical Information of China (English)

    MM Abdullah; Mohammed M Rahman; Houcine Bouzid; M Faisal; Sher Bahadar Khan; SA Al-Sayari; Adel A Ismail

    2015-01-01

    Well crystalline gadolinium oxide (Gd2O3) nanostructures were grown by annealing the hydrothermally as-prepared nanostructures without using any template. Microscopic studies of Gd2O3 nanostructures were recorded along the [111] direction due to the clearly resolved interplanar distance d(222)~0.31 nm of the cubic crystal structure Gd2O3. Sensing mechanism of Gd2O3 as efficient electron mediator for the detection of ethanol was explored. As-fabricated sensor demonstrated the high-sensitivity of~0.266 µAm/M/cm2 with low detection limit (~52.2 µmol/L) and correlation coefficient (r2, 0.618). To the best of our knowledge, this was the first report for the detection of ethanol using as-grown (at 1000 ºC) Gd2O3 nanostructures by simple and reliable I-V technique and rapid assessment of the reaction kinetics (in the order of seconds). The low cost of the starting reagents and the simplicity of the synthetic route made it a promising chemical sensor for the detection of various toxic analytes, which are not en-vironmentally safe.

  18. Chemical etching of Tungsten thin films for high-temperature surface acoustic wave-based sensor devices

    Energy Technology Data Exchange (ETDEWEB)

    Spindler, M., E-mail: m.spindler@ifw-dresden.de [IFW Dresden, SAWLab Saxony, P.O. Box 270116, D-01171 Dresden (Germany); Herold, S.; Acker, J. [BTU Cottbus – Senftenberg, Faculty of Sciences, P.O. Box 101548, 01968 Senftenberg (Germany); Brachmann, E.; Oswald, S.; Menzel, S.; Rane, G. [IFW Dresden, SAWLab Saxony, P.O. Box 270116, D-01171 Dresden (Germany)

    2016-08-01

    Surface acoustic wave devices are widely used as wireless sensors in different application fields. Recent developments aimed to utilize those devices as temperature sensors even in the high temperature range (T > 300 °C) and in harsh environmental conditions. Therefore, conventional materials, which are used for the substrate and for the interdigital transducer finger electrodes such as multilayers or alloys based on Al or Cu have to be exchanged by materials, which fulfill some important criteria regarding temperature related effects. Electron beam evaporation as a standard fabrication method is not well applicable for depositing high temperature stable electrode materials because of their very high melting points. Magnetron sputtering is an alternative deposition process but is also not applicable for lift-off structuring without any further improvement of the structuring process. Due to a relatively high Ar gas pressure of about 10{sup −1} Pa, the sidewalls of the photoresist line structures are also covered by the metallization, which subsequently prevents a successful lift-off process. In this study, we investigate the chemical etching of thin tungsten films as an intermediate step between magnetron sputtering deposition of thin tungsten finger electrodes and the lift-off process to remove sidewall covering for a successful patterning process of interdigital transducers. - Highlights: • We fabricated Tungsten SAW Electrodes by magnetron sputtering technology. • An etching process removes sidewall covering of photoresist, which allows lift-off. • Tungsten etching rates based on a hydrogen peroxide solutions were determined.

  19. Coupled determination of gravimetric and elastic effects on two resonant chemical sensors: love wave and microcantilever platforms.

    Science.gov (United States)

    Fadel, Ludivine; Zimmermann, Céline; Dufour, Isabelle; Déjous, Corinne; Rebière, Dominique; Pistré, Jacques

    2005-02-01

    The objective of this paper is to couple theoretical and experimental results from microcantilevers and Love-wave acoustic devices in order to identify and separate mass loading effects from elastic effects. This is important in the perspective of sensing applications. For that, a thin-film polymer is deposited on both resonant platforms. It is demonstrated that microcantilevers are essentially mass sensitive. They allow one to determine the polymer layer thickness, which is validated by optical profilometry measurements. Then, taking into account this thickness, theoretical modeling and experimental measurements with Love-wave devices permit one to estimate an equivalent elastic shear modulus of the thin-film polymer at high frequency. Results are interesting if one is to fully understand and optimize (bio)chemical sensor responses.

  20. Submicrometer fiber-optic chemical sensors: Measuring pH inside single cells. Progress report, October 1990--August 1993

    Energy Technology Data Exchange (ETDEWEB)

    Kopelman, R.

    1993-12-01

    Starting from scratch, we went in two and a half years to 0.04 micron optical microscopy resolution. We have demonstrated the application of near-field scanning optical microscopy to DNA samples and opened the new fields of near-field scanning spectroscopy and submicron opto- chemical sensors. All of these developments have been important steps towards in-situ DNA imaging and characterization on the nanoscale. Our first goal was to make NSOM (near-field scanning optical microscopy) a working enterprise, capable of ``zooming-in`` towards a sample and imaging with a resolution exceeding that of traditional microscopy by a factor of ten. This has been achieved. Not only do we have a resolution of about 40 nm but we can image a 1 {times} 1 micron object in less than 10 seconds. Furthermore, the NSOM is a practical instrument. The tips survive for days or weeks of scanning and new methods of force feedback will soon protect the most fragile samples. Reproducible images of metal gratings, gold particles, dye balls (for calibration) and of several DNA samples have been made, proving the practicality of our approach. We also give highly resolved Force/NSOM images of human blood cells. Our second goal has been to form molecular optics (e.g., exciton donor) tips with a resolution of 2--10 nm for molecular excitation microscopy (MEM). We have produced such tips, and scanned with them, but only with a resolution comparable to that of our standard NSOM tips. However, we have demonstrated their potential for high resolution imaging capabilities: (1) An energy transfer (tip to sample) based feedback capability. (2) A Kasha (external heavy atom) effect based feedback. In addition, a novel and practical opto-chemical sensor that is a billion times smaller than the best ones available has been developed as well. Finally, we have also performed spatially resolved fluorescence spectroscopy.

  1. 高灵敏共轭聚合物化学传感器%Conjugated Polymers for Sensitive Chemical Sensors

    Institute of Scientific and Technical Information of China (English)

    朱春雷; 杨琼; 刘礼兵; 王树

    2011-01-01

    The detections of metal ion and chemical small molecule are of great importance in view of their influences on human health,environment pollution,and food safety.Thus,considerable researches have been conducted toward designing and developing highly sensitive chemical sensors.In the past few decades,due to the superior electrical properties,conjugated polymers (CPs) have aroused great attentions and numerous revolutionary advances have emerged.More recently,facilitated by their signalamplifying response to sensing events,the possibility of CPs to be used as fluorescent probes toward designing novel chemical and biological sensors have been exploited.This mini account highlights the recent progress of CPs in our group for the detection of metal ion and chemical small molecule based on fluorescence technique.Three different signal transduction mechanisms,including electron transfer,fluorescence resonance energy transfer(FRET) and analyteinduced aggregation or conformational change,are involved in this account and concretely elaborated with corresponding examples.Finally,challenges confronted by CPs and their future directions are discussed.%金属离子和化学小分子的检测在人类健康、环境污染以及食品安全等领域具有重要意义,科学工作者们已经在设计、发展高灵敏化学传感器方面进行了大量研究。在过去的几十年里,共轭聚合物由于其卓越的光电性质,引起了人们极大的关注,并取得了众多革命性科技进展。最近,利用共轭聚合物的荧光信号放大机制,人们设计、发展了一系列新型的化学和生物传感体系。共轭聚合物的信号传感机制包括电子转移,荧光共振能量转移以及共轭聚合物聚集或构象改变。本文主要介绍我们实验室在利用共轭聚合物实现金属离子和化学小分子荧光检测方面取得的进展,并对未来发展方向与面临的挑战进行了讨论。

  2. Chemical detection in liquid media with a refractometric sensor based on a multimode optical fibre

    Directory of Open Access Journals (Sweden)

    V. Matejec

    2002-06-01

    Full Text Available In this paper the physical basis for the design of an optical fibre sensor suited for aqueous medium and gas phase based on the excitation of an evanescent wave at the core/cladding interface is developed. The detection based on the refractive index changes (between 1.41 and 1.45 of the infinite dielectric medium which can be an electrolyte or a sol-gel polymer deposited on the uncladed part of the fibre. Refractive indices of absorbent and volatile compounds such as fuel and unleaded gas were determined. Using a xerogel sensing layer as optical cladding, toluene detection in water was performed. The observed sensitivity is linear and the detection limit is 1% (in volume toluene in water.

  3. Experimental Artifacts for Morphological Tweaking of Chemical Sensor Materials: Studies on ZnO

    Directory of Open Access Journals (Sweden)

    Ikram Ul Haq

    2012-06-01

    Full Text Available Sensing mechanisms of gases on solid structures are predominantly surface-dominated. Benign surface features in terms of small grain size, high aspect ratio, large surface area and open and connected porosity, are required to realize a successful sensor material. Such morphological artifacts are a function of the fabrication and processing techniques employed. In this paper, we describe the fabrication of monoshaped and monosized zinc oxide (ZnO particles by a homogeneous precipitation method, using urea and/or hexmethyltetraamine as the reductant. The effect of operating conditions and experimental variables, such as the relative concentration of the precursors, temperature, and the aging time on the morphology of the resulting particles was studied systematically. These experimental parameters were optimized in order to achieve particles of uniform morphology and of narrow size distribution. Some of these particles were employed for the detection of ammonia gas at room temperature.

  4. Development of a new chemical sensor based on plasma polymerized polypyrrole films

    OpenAIRE

    2010-01-01

    La present tesis contribueix a donar una nova visió dins de l'àrea de modificació de superfícies, la qual implica la nanoestructuració de substrats fent servir la tècnica d'auto-assemblatge per a dipositar sobre aquests un polímer conductor mitjançant deposició química en fase vapor per plasma. L'ús de polímers conductors ha despertat un creixent interès en el desenvolupament de sensors químics per a l'anàlisi de gasos en aplicacions d'enginyeria electrònica. La contínua reducció de mida en a...

  5. Dual-mode bioenabled nano-plasmonic sensors for biological and chemical detection

    Science.gov (United States)

    Kong, Xianming; Squire, Kenny; Xi, Yuting; LeDuff, Paul; Rorrer, Gregory L.; Wang, Alan X.

    2016-03-01

    Plasmonic biosensors have greatly overcome the limitations of conventional optical sensors in terms of sensitivity, tunability, photo-stability, and in vivo applicability. In this paper, we present plasmonic biosensors using bioenabled nanomaterials diatom biosilica, with active surface functionalities as affordable and eco-friendly integration platforms of Ag nanoparticles for label-free detection of biomolecules. Dual-mode plasmon sensing mechanisms, including surface-enhanced Raman scattering (SERS) and refractive-index (RI) sensing will be simultaneously implemented on the plasmonic-biosilica nanostructures to obtain quantitative biosensing with structural resolution of the biomolecules. We have achieved ultra-sensitive detection of Rhodamine 6G (R6G) at concentrations as low as 10-10 M. Furthermore, this substrate was used to detect TNT, illustrating the potential application as viable substrates for monitoring pollutant and toxics in environment.

  6. Beyond potentiometry: robust electrochemical ion sensor concepts in view of remote chemical sensing.

    Science.gov (United States)

    Bakker, Eric; Bhakthavatsalam, Vishnupriya; Gemene, Kebede L

    2008-05-15

    For about 100 years, potentiometry with ion-selective electrodes has been one of the dominating electroanalytical techniques. While great advances in terms of selective chemistries and materials have been achieved in recent years, the basic manner in which ion-selective membranes are used has not fundamentally changed. The potential readings are directly co-dependent on the potential at the reference electrode, which requires maintenance and for which very few accepted alternatives have been proposed. Fouling or clogging of the exposed electrode surfaces will lead to changes in the observed potential. At the same time, the Nernst equation predicts quite small potential changes, on the order of millivolts for concentration changes on the order of a factor two, making frequent recalibration, accurate temperature control and electrode maintenance key requirements of routine analytical measurements. While the relatively advanced selective materials developed for ion-selective sensors would be highly attractive for low power remote sensing application, one should consider solutions beyond classical potentiometry to make this technology practically feasible. This paper evaluates some recent examples that may be attractive solutions to the stated problems that face potentiometric measurements. These include high-amplitude sensing approaches, with sensitivities that are an order of magnitude larger than predicted by the Nernst equation; backside calibration potentiometry, where knowledge of the magnitude of the potential is irrelevant and the system is evaluated from the backside of the membrane; controlled current coulometry with ion-selective membranes, an attractive technique for calibration-free reagent delivery without the need for standards or volumetry; localized electrochemical titrations at ion-selective membranes, making it possible to design sensors that directly monitor parameters such as total acidity for which volumetric techniques were traditionally used

  7. A facile synthesis of mesoporous Pdsbnd ZnO nanocomposites as efficient chemical sensor

    Science.gov (United States)

    Ismail, Adel A.; Harraz, Farid A.; Faisal, M.; El-Toni, Ahmed Mohamed; Al-Hajry, A.; Al-Assiri, M. S.

    2016-07-01

    Mesoporous ZnO was synthesized through the sol-gel method in the presence of triblock co-polymer Pluronic (F-127) template as the structure directing agent. Palladium nanoparticles were photochemically reduced and deposited onto mesoporous ZnO to obtain 1 wt.% Pd/ZnO nanocomposite. Structural and morphological analysis revealed high homogeneity and monodispersity of Pd nanoclusters with small particle sizes ∼ 2-5 nm onto mesoporous ZnO. The electrochemical detection of ethanol in aqueous solutions was conducted at the newly developed Pd/ZnO modified glassy carbon electrode (GCE) by the current-potential (IV) and cyclic voltammetry (CV) techniques and compared with bare GCE or pure ZnO. The presence of Pd dopant greatly enhances the sensitivity of ZnO, and the obtained mesoporous Pd/ZnO sensor has an excellent performance for precision detection of ethanol in aqueous solution with low concentration. The sensitivity was found to be 33.08 μAcm-2 mM-1 at lower concentration zone (0.05-0.8 mM) and 2.13 μAcm-2 mM-1 at higher concentration zone (0.8-12 mM), with a limit of detection (LOD) 19.2 μM. The kinetics study of ethanol oxidation revealed a characteristic feature for a mixed surface and diffusion-controlled process. These excellent sensing characteristics make the mesoporous Pd/ZnO nanocomposite a good candidate for the production of high-performance electrochemical sensors at low ethanol concentration in aqueous solution.

  8. Concept Studies of Micro-Pump for Chemical Concentration in Handheld Micro Sensors

    Science.gov (United States)

    2007-11-02

    This report summarizes the preliminary results of a short-term innovative research project on the concept study of micro pumps for chemical...main objective of the work is to study the feasibility of certain micro pumping concepts and their potential integration with the sensing material and... micro pumps is demonstrated, although the quantitative assessment of the pumping system is still elusive, partly because of lack of specifications. The

  9. Assessment of diffusion parameters of new passive samplers using optical chemical sensor for on-site measuring formaldehyde in indoor air: experimental and numerical studies.

    Science.gov (United States)

    Vignau-Laulhere, Jane; Mocho, Pierre; Plaisance, Hervé; Raulin, Katarzyna; Desauziers, Valérie

    2016-03-01

    New passive samplers using a sensor consisting of a sol-gel matrix entrapping Fluoral-P as sampling media were developed for the determination of formaldehyde in indoor air. The reaction between Fluoral-P and formaldehyde produces a colored compound which is quantified on-site by means of a simple optical reading module. The advantages of this sensor are selectivity, low cost, ppb level limit of detection, and on-site direct measurement. In the development process, it is necessary to determine the sampling rate, a key parameter that cannot be directly assessed in the case of diffusive samplers using optical chemical sensor. In this study, a methodology combining experimental tests and numerical modeling is proposed and applied at five different radial diffusive samplers equipped with the same optical chemical sensor to assess the sampled material flows and sampling rates. These radial diffusive samplers differ in the internal volume of the sampler (18.97 and 6.14 cm(3)), the position of sensor inside the sampler (in front and offset of 1.2 cm above the membrane) and the width of the diffusion slot (1.4 and 5.9 mm). The influences of these three parameters (internal volume, position of sensor inside the sampler, and width of the diffusion slot) were assessed and discussed with regard to the formaldehyde sampling rate and water uptake by sensor (potential interference of measure). Numerical simulations based on Fick's laws are in agreement with the experimental results and provide to estimate the effective diffusion coefficient of formaldehyde through the membrane (3.50 × 10(-6) m(2) s(-1)). Conversion factors between the sensor response, sampled formaldehyde mass and sampling rate were also assessed.

  10. Selectivity of Chemoresistive Sensors Made of Chemically Functionalized Carbon Nanotube Random Networks for Volatile Organic Compounds (VOC

    Directory of Open Access Journals (Sweden)

    Jean-François Feller

    2014-01-01

    Full Text Available Different grades of chemically functionalized carbon nanotubes (CNT have been processed by spraying layer-by-layer (sLbL to obtain an array of chemoresistive transducers for volatile organic compound (VOC detection. The sLbL process led to random networks of CNT less conductive, but more sensitive to vapors than filtration under vacuum (bucky papers. Shorter CNT were also found to be more sensitive due to the less entangled and more easily disconnectable conducting networks they are making. Chemical functionalization of the CNT’ surface is changing their selectivity towards VOC, which makes it possible to easily discriminate methanol, chloroform and tetrahydrofuran (THF from toluene vapors after the assembly of CNT transducers into an array to make an e-nose. Interestingly, the amplitude of the CNT transducers’ responses can be enhanced by a factor of five (methanol to 100 (chloroform by dispersing them into a polymer matrix, such as poly(styrene (PS, poly(carbonate (PC or poly(methyl methacrylate (PMMA. COOH functionalization of CNT was found to penalize their dispersion in polymers and to decrease the sensors’ sensitivity. The resulting conductive polymer nanocomposites (CPCs not only allow for a more easy tuning of the sensors’ selectivity by changing the chemical nature of the matrix, but they also allow them to adjust their sensitivity by changing the average gap between CNT (acting on quantum tunneling in the CNT network. Quantum resistive sensors (QRSs appear promising for environmental monitoring and anticipated disease diagnostics that are both based on VOC analysis.

  11. Chemically Driven Printed Textile Sensors Based on Graphene and Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Ewa Skrzetuska

    2014-09-01

    Full Text Available The unique properties of graphene, such as the high elasticity, mechanical strength, thermal conductivity, very high electrical conductivity and transparency, make them it an interesting material for stretchable electronic applications. In the work presented herein, the authors used graphene and carbon nanotubes to introduce chemical sensing properties into textile materials by means of a screen printing method. Carbon nanotubes and graphene pellets were dispersed in water and used as a printing paste in the screen printing process. Three printing paste compositions were prepared—0%, 1% and 3% graphene pellet content with a constant 3% carbon nanotube mass content. Commercially available materials were used in this process. As a substrate, a twill woven cotton fabric was utilized. It has been found that the addition of graphene to printing paste that contains carbon nanotubes significantly enhances the electrical conductivity and sensing properties of the final product.

  12. A progress report on the LDRD project entitled {open_quotes}Microelectronic silicon-based chemical sensors: Ultradetection of high value molecules{close_quotes}

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, R.C.

    1996-09-01

    This work addresses a new kind of silicon based chemical sensor that combines the reliability and stability of silicon microelectronic field effect devices with the highly selective and sensitive immunoassay. The sensor works on the principle that thin SiN layers on lightly doped Si can detect pH changes rapidly and reversibly. The pH changes affect the surface potential, and that can be quickly determined by pulsed photovoltage measurements. To detect other species, chemically sensitive films were deposited on the SiN where the presence of the chosen analyte results in pH changes through chemical reactions. A invention of a cell sorting device based on these principles is also described. A new method of immobilizing enzymes using Sandia`s sol-gel glasses is documented and biosensors based on the silicon wafer and an amperometric technique are detailed.

  13. Chemical Gated Field Effect Transistor by Hybrid Integration of One-Dimensional Silicon Nanowire and Two-Dimensional Tin Oxide Thin Film for Low Power Gas Sensor.

    Science.gov (United States)

    Han, Jin-Woo; Rim, Taiuk; Baek, Chang-Ki; Meyyappan, M

    2015-09-30

    Gas sensors based on metal-oxide-semiconductor transistor with the polysilicon gate replaced by a gas sensitive thin film have been around for over 50 years. These are not suitable for the emerging mobile and wearable sensor platforms due to operating voltages and powers far exceeding the supply capability of batteries. Here we present a novel approach to decouple the chemically sensitive region from the conducting channel for reducing the drive voltage and increasing reliability. This chemically gated field effect transistor uses silicon nanowire for the current conduction channel with a tin oxide film on top of the nanowire serving as the gas sensitive medium. The potential change induced by the molecular adsorption and desorption allows the electrically floating tin oxide film to gate the silicon channel. As the device is designed to be normally off, the power is consumed only during the gas sensing event. This feature is attractive for the battery operated sensor and wearable electronics. In addition, the decoupling of the chemical reaction and the current conduction regions allows the gas sensitive material to be free from electrical stress, thus increasing reliability. The device shows excellent gas sensitivity to the tested analytes relative to conventional metal oxide transistors and resistive sensors.

  14. Synthesis and Characterization of Vanadium Doped Zinc Oxide Thick Film for Chemical Sensor Application

    Directory of Open Access Journals (Sweden)

    Rayees Ahmad Zargar

    2015-01-01

    Full Text Available Zinc oxide and vanadium pentoxide nanoparticles derived by chemical coprecipitation route were used to cast Zn0.96V0.04O thick film by screen printing method. The structural, morphological, optical, and electrical properties of the film were characterized by powder XRD, SEM, Raman, UV-VIS, and DC conductivity techniques. XRD pattern, SEM image, and Raman spectrum of the film confirm the single phase formation of Wurtzite structure with preferential orientation along [101] plane, minor variation in lattice parameters, and vanadium ions substitution at zinc sites. Zn0.96V0.04O pellet has been used for sensing ammonia vapor concentrations in 20–50°C temperature range which exhibits maximum responsiveness and sensitivity at 30°C. The minor variations in resistance are observed with ammonia vapor concentration. The adsorption of ammonia vapors through weak hydrogen bonding and its insertion into lattice by nitrogen lone pairs donation at vacant/defect sites in lattice caused by vanadium doping are considered to explain gas sensing mechanism.

  15. Synthesis of ZnO nanopencils using wet chemical method and its investigation as LPG sensor

    Science.gov (United States)

    Shimpi, Navinchandra G.; Jain, Shilpa; Karmakar, Narayan; Shah, Akshara; Kothari, D. C.; Mishra, Satyendra

    2016-12-01

    ZnO nanopencils (NPCs) were prepared by a novel wet chemical process, using triethanolamine (TEA) as a mild base, which is relatively simple and cost effective method as compared to hydrothermal method. ZnO NPCs were characterized using powder X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy in mid-IR and far-IR regions, X-ray Photoelectron Spectroscopy (XPS), UV-vis (UV-vis) absorption spectroscopy, room temperature Photoluminescence (PL) spectroscopy and Field Emission Scanning Electron Microscopy (FESEM). ZnO NPCs obtained, were highly pure, uniform and monodispersed.XRD pattern indicated hexagonal unit cell structure with preferred orientation along the c-axis. Sensing behaviour of ZnO NPCs was studied towards Liquefied Petroleum Gas (LPG) at different operating temperatures. The study shows that ZnO NPCs were most sensitive and promising candidate for detection of LPG at 250 °C with gas sensitivity > 60%. The high response towards LPG is due to high surface area of ZnO NPCs and their parallel alignment.

  16. Computational understanding and experimental characterization of twice-as-smart quadruplex ligands as chemical sensors of bacterial nucleotide second messengers

    Science.gov (United States)

    Zhou, Jie; Roembke, Benjamin T.; Paragi, Gabor; Laguerre, Aurélien; Sintim, Herman O.; Fonseca Guerra, Célia; Monchaud, David

    2016-01-01

    A twice-as-smart ligand is a small molecule that experiences a structural switch upon interaction with its target (i.e., smart ligand) that concomitantly triggers its fluorescence (i.e., smart probe). Prototypes of twice-as-smart ligands were recently developed to track and label G-quadruplexes: these higher-order nucleic acid structures originate in the assembly of four guanine(G)-rich DNA or RNA strands, whose stability is imparted by the formation and the self-assembly of G-quartets. The first prototypes of twice-as-smart quadruplex ligands were designed to exploit the self-association of quartets, being themselves synthetic G-quartets. While their quadruplex recognition capability has been thoroughly documented, some doubts remain about the precise photophysical mechanism that underlies their peculiar spectroscopic properties. Here, we uncovered this mechanism via complete theoretical calculations. Collected information was then used to develop a novel application of twice-as-smart ligands, as efficient chemical sensors of bacterial signaling pathways via the fluorescent detection of naturally occurring extracellular quadruplexes formed by cyclic dimeric guanosine monophosphate (c-di-GMP). PMID:27667717

  17. Soft sensor of chemical processes with large numbers of input parameters using auto-associative hierarchical neural network

    Institute of Scientific and Technical Information of China (English)

    Yanlin He; Yuan Xu; Zhiqiang Geng; Qunxiong Zhu

    2015-01-01

    To explore the problems of monitoring chemical processes with large numbers of input parameters, a method based on Auto-associative Hierarchical Neural Network (AHNN) is proposed. AHNN focuses on dealing with datasets in high-dimension. AHNNs consist of two parts:groups of subnets based on well trained Auto-associative Neural Networks (AANNs) and a main net. The subnets play an important role on the performance of AHNN. A simple but effective method of designing the subnets is developed in this paper. In this method, the subnets are designed according to the classification of the data attributes. For getting the classification, an effective method called Extension Data Attributes Classification (EDAC) is adopted. Soft sensor using AHNN based on EDAC (EDAC-AHNN) is introduced. As a case study, the production data of Purified Terephthalic Acid (PTA) solvent system are selected to examine the proposed model. The results of the EDAC-AHNN model are compared with the experimental data extracted from the literature, which shows the efficiency of the proposed model.

  18. Chemical-Assisted Femtosecond Laser Writing of Lab-in-Fiber Sensors

    Science.gov (United States)

    Haque, Moez

    fringe contrast and peak resolution beyond that available with FPIs and offer a significant theoretical improvement in refractometer sensitivity. The advanced laser processes optimized here may provide a new base for photonics, microfluidics, and optofluidics fabrication in a LIF platform with multiplexed functionality and rapid prototyping capabilities of fully integrable 3D optofluidic systems. The proposed LIF devices define new micro-systems for temperature, strain, pressure, refractive index, and bend strain sensing that may find application in the acoustic, aerospace, automotive, biological, chemical, civil, or medical fields.

  19. Development of Zr/ZrO2 high temperature and high pressure sensors for in-situ measuring chemical parameters of deep-sea water

    Institute of Scientific and Technical Information of China (English)

    ZHANG XueTong; ZHANG RongHua; HU ShuMin; WANG Yong

    2009-01-01

    In order to in situ measure chemical parameters of deep-sea water and hydrothermal fluids at midocean ridge(MOR),it is necessary to use high temperature and high pressure chemical sensors.Developing new sensors is essential to measure in-situ pH and other chemical parameters(dissolved H2,dissolved H2S)of deep-sea water and hydrothermal fluids in a wide temperature range(2℃-400℃)at MOR vents.The YSZ(Yttria Stabilized Zirconia,9%Y2O3)ceramic-based(HgO/Hg)chemical sensors possess excellent electrochemical properties at high temperatures,which have been used to measure chemical parameters of hydrothermsl fluids above 200℃.A novel Zr/ZrO2 oxidation/reduction electrode was constructed by oxidation of Zr wire in Na2CO3 melt.This Zr/ZrO2 electrode has good chemical stability while measuring pH of high-temperature aqueous solutions,combined with a Ag/AgCl reference electrode.Potentials of the Zr/ZrO2 sensor in association with a Ag/AgCl reference electrode vary linearly with pH over a wide pH range,as tested by various NaCI-HCI-H2O solutions(NaOH-NaCI-H2O for basic solutions),at temperatures in the range of 20℃-200℃.Thus,the Zr/ZrO2 sensors can be utilized in monitoring the fluids over the temperature range of 2℃-200℃.The Zr/ZrO2 electrode combined with Ag/AgCI,Ag/Ag2S,and Au electrodes has been used to measure pH and other chemical parameters (dissolved H2,dissolved H2S)of aqueous fluids from low to high temperatures and high pressures in the laboratory and to monitor those parameters of deep-sea water in South China Sea.

  20. Development of Zr/ZrO2 high temperature and high pressure sensors for in-situ measuring chemical parameters of deep-sea water

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In order to in situ measure chemical parameters of deep-sea water and hydrothermal fluids at midocean ridge(MOR), it is necessary to use high temperature and high pressure chemical sensors.Developing new sensors is essential to measure in-situ pH and other chemical parameters(dissolved H2, dissolved H2S) of deep-sea water and hydrothermal fluids in a wide temperature range(2℃―400℃) at MOR vents.The YSZ(Yttria Stabilized Zirconia, 9%Y2O3) ceramic-based(HgO/Hg) chemical sensors possess excellent electrochemical properties at high temperatures, which have been used to measure chemical parameters of hydrothermal fluids above 200℃.A novel Zr/ZrO2 oxidation/reduction electrode was constructed by oxidation of Zr wire in Na2CO3 melt.This Zr/ZrO2 electrode has good chemical stability while measuring pH of high-temperature aqueous solutions, combined with a Ag/AgCl reference electrode.Potentials of the Zr/ZrO2 sensor in association with a Ag/AgCl reference electrode vary linearly with pH over a wide pH range, as tested by various NaCl-HCl-H2O solutions(NaOH-NaCl-H2O for basic solutions), at temperatures in the range of 20℃―200℃.Thus, the Zr/ZrO2 sensors can be utilized in monitoring the fluids over the temperature range of 2℃―200℃.The Zr/ZrO2 electrode combined with Ag/AgCl, Ag/Ag2S, and Au electrodes has been used to measure pH and other chemical parameters(dissolved H2, dissolved H2S) of aqueous fluids from low to high temperatures and high pressures in the laboratory and to monitor those parameters of deep-sea water in South China Sea.

  1. Highly-Sensitive Surface-Enhanced Raman Spectroscopy (SERS)-based Chemical Sensor using 3D Graphene Foam Decorated with Silver Nanoparticles as SERS substrate

    Science.gov (United States)

    Srichan, Chavis; Ekpanyapong, Mongkol; Horprathum, Mati; Eiamchai, Pitak; Nuntawong, Noppadon; Phokharatkul, Ditsayut; Danvirutai, Pobporn; Bohez, Erik; Wisitsoraat, Anurat; Tuantranont, Adisorn

    2016-03-01

    In this work, a novel platform for surface-enhanced Raman spectroscopy (SERS)-based chemical sensors utilizing three-dimensional microporous graphene foam (GF) decorated with silver nanoparticles (AgNPs) is developed and applied for methylene blue (MB) detection. The results demonstrate that silver nanoparticles significantly enhance cascaded amplification of SERS effect on multilayer graphene foam (GF). The enhancement factor of AgNPs/GF sensor is found to be four orders of magnitude larger than that of AgNPs/Si substrate. In addition, the sensitivity of the sensor could be tuned by controlling the size of silver nanoparticles. The highest SERS enhancement factor of ∼5 × 104 is achieved at the optimal nanoparticle size of 50 nm. Moreover, the sensor is capable of detecting MB over broad concentration ranges from 1 nM to 100 μM. Therefore, AgNPs/GF is a highly promising SERS substrate for detection of chemical substances with ultra-low concentrations.

  2. A SAW-Based Chemical Sensor for Detecting Sulfur-Containing Organophosphorus Compounds Using a Two-Step Self-Assembly and Molecular Imprinting Technology

    Directory of Open Access Journals (Sweden)

    Yong Pan

    2014-05-01

    Full Text Available This paper presents a new effective approach for the sensitive film deposition of surface acoustic wave (SAW chemical sensors for detecting organophosphorus compounds such as O-ethyl-S-2-diisopropylaminoethyl methylphosphonothiolate (VX containing sulfur at extremely low concentrations. To improve the adsorptive efficiency, a two-step technology is proposed for the sensitive film preparation on the SAW delay line utilizing gold electrodes. First, mono[6-deoxy-6-[(mercaptodecamethylenethio

  3. The Different Sensitive Behaviors of a Hydrogen-Bond Acidic Polymer-Coated SAW Sensor for Chemical Warfare Agents and Their Simulants

    Directory of Open Access Journals (Sweden)

    Yin Long

    2015-07-01

    Full Text Available A linear hydrogen-bond acidic (HBA linear functionalized polymer (PLF, was deposited onto a bare surface acoustic wave (SAW device to fabricate a chemical sensor. Real-time responses of the sensor to a series of compounds including sarin (GB, dimethyl methylphosphonate (DMMP, mustard gas (HD, chloroethyl ethyl sulphide (2-CEES, 1,5-dichloropentane (DCP and some organic solvents were studied. The results show that the sensor is highly sensitive to GB and DMMP, and has low sensitivity to HD and DCP, as expected. However, the sensor possesses an unexpected high sensitivity toward 2-CEES. This good sensing performance can’t be solely or mainly attributed to the dipole-dipole interaction since the sensor is not sensitive to some high polarity solvents. We believe the lone pair electrons around the sulphur atom of 2-CEES provide an electron-rich site, which facilitates the formation of hydrogen bonding between PLF and 2-CEES. On the contrary, the electron cloud on the sulphur atom of the HD molecule is offset or depleted by its two neighbouring strong electron-withdrawing groups, hence, hydrogen bonding can hardly be formed.

  4. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  5. Chemically modified carbon paste and membrane sensors for the determination of benzethonium chloride and some anionic surfactants (SLES, SDS, and LABSA): Characterization using SEM and AFM.

    Science.gov (United States)

    Issa, Yousry M; Mohamed, Sabrein H; Baset, Mohamed Abd-El

    2016-08-01

    Chemically modified carbon-paste (CMCP) and membrane- sensors based on incorporating benzothonium-tetraphenylborate (BT-TPB) were constructed for the analysis of benzethonium chloride, and some other surfactants such as sodium lauryl ether sulphate (SLES), sodium dodecyl sulphate (SDS), and linear alkylbenzene sulphonic acid (LABSA). All sensors showed good sensitivity and reverse wide linearity over a concentration range of 5.97×10(-7) to 1.00×10(-3) and 5.96×10(-7) to 3.03×10(-3)molL(-1) with limit of detection of 3.92×10(-7)and 3.40×10(-7)molL(-1) for membrane and chemically modified carbon paste sensors, respectively, with respect to benzethonium chloride (BT.Cl). They could be used over a wide pH range of 2.0-10.0. The thermal coefficients of membrane and CMCP sensors are 5.40×10(-4), 1.17×10(-4)V/°C, respectively. The sensors indicated a wide selectivity over different inorganic cations. The effect of soaking on the surface morphology of the membrane sensor was studied using EDX-SEM and AFM techniques. The response time was <10s The freshly prepared, exhausted membrane, and CMCP sensors were successfully applied for the potentiometric determination of the pure BT.Cl solution. They were also used for the determination of its pharmaceutical formulation Dermoplast(®) antibacterial spray (20% benzocaine+0.2% benzethonium chloride) with recovery values ranging from 97.54±1.70 to 101.25±1.12 and from 96.32±2.49 to 101.23±2.15%. The second goal of these sensors is the potentiometric determination of different surfactants such as SLES, SDS, and LABSA with good recovery values using BT.Cl as a titrant in their pure forms, and in samples containing one of them (shampoo, Touri(®) dishwashing liquid, and waste water). The statistical analysis of the obtained data was studied.

  6. Chemical, physical, and other data collected using meteorological sensors, secchi disk, and bottle casts from the NEW HORIZON as part of the California Cooperative Fisheries Investigation (CALCOFI) project, for 1980-11-12 (NODC Accession 8900096)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chemical, physical, and other data were collected from the NEW HORIZON from November 12, 1980 to November 12, 1980. Data were collected using meteorological sensors,...

  7. Research on Acetylene Sensing Properties and Mechanism of SnO2 Based Chemical Gas Sensor Decorated with Sm2O3

    Directory of Open Access Journals (Sweden)

    Qu Zhou

    2015-01-01

    Full Text Available Acetylene C2H2 gas is one of the most important fault characteristic hydrocarbon gases dissolved in oil immersed power transformer oil. This paper reports the successful preparation and characterization of samarium oxide Sm2O3 decorated tin oxide SnO2 based sensors with hierarchical rod structure for C2H2 gas detection. Pure and Sm2O3 decorated SnO2 sensing structures were synthesized by a facile hydrothermal method and characterized by XRD, FESEM, TEM, EDS, and XPS measurements, respectively. Planar chemical gas sensors with the synthesis samples were fabricated, and their sensing performances to C2H2 gas were systematically performed and automatically recorded by a CGS-1 TP intelligent gas sensing analysis system. The optimum operating temperature of the Sm2O3 decorated SnO2 based sensor towards 50 μL/L of C2H2 is 260°C, and its corresponding response value is 38.12, which is 6 times larger than the pure one. Its response time is about 8–10 s and 10–13 s for recovery time. Meanwhile good stability and reproducibility of the decorated sensor to C2H2 gas are also obtained. Furthermore, the proposed sensor exhibits excellent C2H2 selectivity among some potential interface gases, like H2 and CO gas. All sensing results indicate the sensor fabricated with oxide Sm2O3 decorated SnO2 nanorods might be a promising candidate for C2H2 detection in practice.

  8. Submersible optical sensors exposed to chemically dispersed crude oil: wave tank simulations for improved oil spill monitoring.

    Science.gov (United States)

    Conmy, Robyn N; Coble, Paula G; Farr, James; Wood, A Michelle; Lee, Kenneth; Pegau, W Scott; Walsh, Ian D; Koch, Corey R; Abercrombie, Mary I; Miles, M Scott; Lewis, Marlon R; Ryan, Scott A; Robinson, Brian J; King, Thomas L; Kelble, Christopher R; Lacoste, Jordanna

    2014-01-01

    In situ fluorometers were deployed during the Deepwater Horizon (DWH) Gulf of Mexico oil spill to track the subsea oil plume. Uncertainties regarding instrument specifications and capabilities necessitated performance testing of sensors exposed to simulated, dispersed oil plumes. Dynamic ranges of the Chelsea Technologies Group AQUAtracka, Turner Designs Cyclops, Satlantic SUNA and WET Labs, Inc. ECO, exposed to fresh and artificially weathered crude oil, were determined. Sensors were standardized against known oil volumes and total petroleum hydrocarbons and benzene-toluene-ethylbenzene-xylene measurements-both collected during spills, providing oil estimates during wave tank dilution experiments. All sensors estimated oil concentrations down to 300 ppb oil, refuting previous reports. Sensor performance results assist interpretation of DWH oil spill data and formulating future protocols.

  9. Eu(III) complexes as anion-responsive luminescent sensors and paramagnetic chemical exchange saturation transfer agents.

    Science.gov (United States)

    Hammell, Jacob; Buttarazzi, Leandro; Huang, Ching-Hui; Morrow, Janet R

    2011-06-06

    The Eu(III) complex of (1S,4S,7S,10S)-1,4,7,10-tetrakis(2-hydroxypropyl)-1,4,7,10-tetraazacyclododecane (S-THP) is studied as a sensor for biologically relevant anions. Anion interactions produce changes in the luminescence emission spectrum of the Eu(III) complex, in the (1)H NMR spectrum, and correspondingly, in the PARACEST spectrum of the complex (PARACEST = paramagnetic chemical exchange saturation transfer). Direct excitation spectroscopy and luminescence lifetime studies of Eu(S-THP) give information about the speciation and nature of anion interactions including carbonate, acetate, lactate, citrate, phosphate, and methylphosphate at pH 7.2. Data is consistent with the formation of both innersphere and outersphere complexes of Eu(S-THP) with acetate, lactate, and carbonate. These anions have weak dissociation constants that range from 19 to 38 mM. Citrate binding to Eu(S-THP) is predominantly innersphere with a dissociation constant of 17 μM. Luminescence emission peak changes upon addition of anion to Eu(S-THP) show that there are two distinct binding events for phosphate and methylphosphate with dissociation constants of 0.3 mM and 3.0 mM for phosphate and 0.6 mM and 9.8 mM for methyl phosphate. Eu(THPC) contains an appended carbostyril derivative as an antenna to sensitize Eu(III) luminescence. Eu(THPC) binds phosphate and citrate with dissociation constants that are 10-fold less than that of the Eu(S-THP) parent, suggesting that functionalization through a pendent group disrupts the anion binding site. Eu(S-THP) functions as an anion responsive PARACEST agent through exchange of the alcohol protons with bulk water. The alcohol proton resonances of Eu(S-THP) shift downfield in the presence of acetate, lactate, citrate, and methylphosphate, giving rise to distinct PARACEST peaks. In contrast, phosphate binds to Eu(S-THP) to suppress the PARACEST alcohol OH peak and carbonate does not markedly change the alcohol peak at 5 mM Eu(S-THP), 15 mM carbonate at p

  10. Response Behaviour of a Hydrogen Sensor Based on IonicConducting Polymer-metal Interfaces Prepared by the ChemicalReduction Method

    Directory of Open Access Journals (Sweden)

    Werner Weppner

    2006-04-01

    Full Text Available A solid-state amperometric hydrogen sensor based on a protonated Nafionmembrane and catalytic active electrode operating at room temperature was fabricated andtested. Ionic conducting polymer-metal electrode interfaces were prepared chemically byusing the impregnation-reduction method. The polymer membrane was impregnated withtetra-ammine platinum chloride hydrate and the metal ions were subsequently reduced byusing either sodium tetrahydroborate or potassium tetrahydroborate. The hydrogen sensingcharacteristics with air as reference gas is reported. The sensors were capable of detectinghydrogen concentrations from 10 ppm to 10% in nitrogen. The response time was in therange of 10-30 s and a stable linear current output was observed. The thin Pt films werecharacterized by XRD, Infrared Spectroscopy, Optical Microscopy, Atomic ForceMicroscopy, Scanning Electron Microscopy and EDAX.

  11. Graphene oxide as sensitive layer in Love-wave surface acoustic wave sensors for the detection of chemical warfare agent simulants.

    Science.gov (United States)

    Sayago, Isabel; Matatagui, Daniel; Fernández, María Jesús; Fontecha, José Luis; Jurewicz, Izabela; Garriga, Rosa; Muñoz, Edgar

    2016-02-01

    A Love-wave device with graphene oxide (GO) as sensitive layer has been developed for the detection of chemical warfare agent (CWA) simulants. Sensitive films were fabricated by airbrushing GO dispersions onto Love-wave devices. The resulting Love-wave sensors detected very low CWA simulant concentrations in synthetic air at room temperature (as low as 0.2 ppm for dimethyl-methylphosphonate, DMMP, a simulant of sarin nerve gas, and 0.75 ppm for dipropylene glycol monomethyl ether, DPGME, a simulant of nitrogen mustard). High responses to DMMP and DPGME were obtained with sensitivities of 3087 and 760 Hz/ppm respectively. Very low limit of detection (LOD) values (9 and 40 ppb for DMMP and DPGME, respectively) were calculated from the achieved experimental data. The sensor exhibited outstanding sensitivity, good linearity and repeatability to all simulants tested. The detection mechanism is here explained in terms of hydrogen bonding formation between the tested CWA simulants and GO.

  12. Highly sensitive sensing of zinc(II) by development and characterization of a PVC-based fluorescent chemical sensor

    Science.gov (United States)

    Aksuner, Nur; Henden, Emur; Yenigul, Berrin; Yilmaz, Ibrahim; Cukurovali, Alaaddin

    2011-03-01

    A sensor membrane with excellent performance based on 1-methyl-1-phenyl-3-[1-hydroxyimino-2-(succinimido)ethyl]cyclobutane has been developed for the determination of zinc(II) ions. The sensing membrane is capable of determining zinc(II) with an outstanding high selectivity over a dynamic range between 8.0 × 10 -8 and 1.6 × 10 -4 mol L -1 with a limit of detection of 2.5 × 10 -8 mol L -1 (1.6 μg L -1). It can be easily and completely regenerated by using 0.1 mol L -1 EDTA solution. The optical sensor developed here was found to be stable, cost effective, easy to prepare, and has unique selectivity towards Zn 2+ ion with respect to common metal ions. The proposed sensor was then applied for the determination of zinc in tap water and hair samples with satisfactory results.

  13. Triboelectric nanogenerators as new energy technology for self-powered systems and as active mechanical and chemical sensors.

    Science.gov (United States)

    Wang, Zhong Lin

    2013-11-26

    Triboelectrification is an effect that is known to each and every one probably since ancient Greek time, but it is usually taken as a negative effect and is avoided in many technologies. We have recently invented a triboelectric nanogenerator (TENG) that is used to convert mechanical energy into electricity by a conjunction of triboelectrification and electrostatic induction. As for this power generation unit, in the inner circuit, a potential is created by the triboelectric effect due to the charge transfer between two thin organic/inorganic films that exhibit opposite tribo-polarity; in the outer circuit, electrons are driven to flow between two electrodes attached on the back sides of the films in order to balance the potential. Since the most useful materials for TENG are organic, it is also named organic nanogenerator, which is the first using organic materials for harvesting mechanical energy. In this paper, we review the fundamentals of the TENG in the three basic operation modes: vertical contact-separation mode, in-plane sliding mode, and single-electrode mode. Ever since the first report of the TENG in January 2012, the output power density of TENG has been improved 5 orders of magnitude within 12 months. The area power density reaches 313 W/m(2), volume density reaches 490 kW/m(3), and a conversion efficiency of ∼60% has been demonstrated. The TENG can be applied to harvest all kinds of mechanical energy that is available but wasted in our daily life, such as human motion, walking, vibration, mechanical triggering, rotating tire, wind, flowing water, and more. Alternatively, TENG can also be used as a self-powered sensor for actively detecting the static and dynamic processes arising from mechanical agitation using the voltage and current output signals of the TENG, respectively, with potential applications for touch pad and smart skin technologies. To enhance the performance of the TENG, besides the vast choices of materials in the triboelectric

  14. Influence of the physical–chemical properties of polyaniline thin films on the final sensitivity of varied field effect sensors

    Energy Technology Data Exchange (ETDEWEB)

    Mello, Hugo José Nogueira Pedroza Dias, E-mail: hugodiasmello@usp.br; Heimfarth, Tobias; Mulato, Marcelo

    2015-06-15

    We investigated the use of electrodeposited polyaniline (PANI) thin sensing films in pH sensors. Two configurations of the Extended Gate Field Effect Transistor (EGFET) sensor were studied: the Single EGFET (S-EGFET) and the Instrumental Amplifier EGFET (IA-EGFET) setups. The films were analyzed in both systems and the sensitivity and linearity of each sensor were compared. Initial sensitivities (70–80 mV/pH) measured in the IA-EGFET were reduced due to polymer bulk protonation after a prior measurement in the S-EGFET system. Films with high amount of deposited polymer had their sensitivities least reduced. Bulk protonation occurred due to the step potential applied to the reference electrode in the S-EGFET system. These changes were also analyzed by scanning electron microscopy (SEM), visible reflectance spectroscopy and evaluation of CIE L*a*b* color scale. PANI pH EGFET sensors exhibited good linearity and stability that along with their high sensitivity, easy processing and low cost film production have large potential applications. - Highlights: • Electrodeposited polyaniline thin films were analyzed in two EGFET setups. • Polymer protonation provided changeable sensitivities. • Color and morphological variation confirm polymer aggregation and electrical changes.

  15. Onsite-detection of barium and nickel from river, pond and tap water samples using gold nanoparticles as a chemical sensor

    Science.gov (United States)

    Shrivas, Kamlesh; Maji, Pathik; Dewangan, Khemchand

    2017-02-01

    We report a simple, selective and sensitive colorimetric assay for onsite determination of Ni(II) and Ba(II) from river, pond and tap water samples using the localized surface plasmon resonance (LSPR) of malonate capped gold nanoparticles (AuNPs) as a chemical sensor. The method is based on the color change and red shift of LSPR absorption band in visible region that caused by the aggregation of NPs because of the coordination complex between Ba(II) and Ni(II) with carboxylate ions of malonate capped AuNPs. The determination of Ba(II) and NI(II) in a same sample was performed by masking one of the analyte at a time, EDTA was used to mask Ni(II) for detection of Ba(II) and dilute H2SO4 was used to mask the Ba(II) for detection of Ni(II). The linear range for quantitative determination of Ba(II) and NI(II) were found in the range of 15-500 and 10-500 ng mL- 1 with a limit of detection of 5 and 3 ng mL- 1, respectively. The advantages of the AuNPs based chemical sensor is found to be simple, rapid and sensitive as well as it can be applied at the sample source for trace detection of Ba(II) and Ni(II) in various environmental samples.

  16. The Construct of A Neutral Medium Applicable Electrochemiluminescent Sensor Based on the Chemical Modification of Cysteine and Luminol

    Institute of Scientific and Technical Information of China (English)

    Tu Yifeng; Chu Haihong; Guo Wenying; Di Junwei

    2006-01-01

    In the phosphate buffer solution of pH>7, the cysteine sensitized the electrochemiluminescence (ECL) of luminol. It could be modified on the surface of platinum electrode and furthermore adsorbing the luminol on its exterior to construct an ECL sensor. The ECL intensity of this sensor was strong enough and very stable. There wasn't obvious decrease of ECL intensity for thirty times of using in 48 hours with the relative standard deviation (RSD) of 0.98%. It could be used to determine some quenching effective molecules such as superoxide dismutase (SOD) with negative response upon the concentration range from 4.8 IU/ml to 57.6 IU/ml.

  17. Optical Fiber Chemical Sensor with Sol-Gel Derived Refractive Material as Transducer for High Temperature Gas Sensing in Clean Coal Technology

    Energy Technology Data Exchange (ETDEWEB)

    Shiquan Tao

    2006-12-31

    The chemistry of sol-gel derived silica and refractive metal oxide has been systematically studied. Sol-gel processes have been developed for preparing porous silica and semiconductor metal oxide materials. Micelle/reversed micelle techniques have been developed for preparing nanometer sized semiconductor metal oxides and noble metal particles. Techniques for doping metal ions, metal oxides and nanosized metal particles into porous sol-gel material have also been developed. Optical properties of sol-gel derived materials in ambient and high temperature gases have been studied by using fiber optic spectroscopic techniques, such as fiber optic ultraviolet/visible absorption spectrometry, fiber optic near infrared absorption spectrometry and fiber optic fluorescence spectrometry. Fiber optic spectrometric techniques have been developed for investigating the optical properties of these sol-gel derived materials prepared as porous optical fibers or as coatings on the surface of silica optical fibers. Optical and electron microscopic techniques have been used to observe the microstructure, such as pore size, pore shape, sensing agent distribution, of sol-gel derived material, as well as the size and morphology of nanometer metal particle doped in sol-gel derived porous silica, the nature of coating of sol-gel derived materials on silica optical fiber surface. In addition, the chemical reactions of metal ion, nanostructured semiconductor metal oxides and nanometer sized metal particles with gas components at room temperature and high temperatures have also been investigated with fiber optic spectrometric methods. Three classes of fiber optic sensors have been developed based on the thorough investigation of sol-gel chemistry and sol-gel derived materials. The first group of fiber optic sensors uses porous silica optical fibers doped with metal ions or metal oxide as transducers for sensing trace NH{sub 3} and H{sub 2}S in high temperature gas samples. The second group of

  18. On-line sensor monitoring for chemical contaminant attenuation during UV/H2O2 advanced oxidation process.

    Science.gov (United States)

    Yu, Hye-Weon; Anumol, Tarun; Park, Minkyu; Pepper, Ian; Scheideler, Jens; Snyder, Shane A

    2015-09-15

    A combination of surrogate parameters and indicator compounds were measured to predict the removal efficiency of trace organic compounds (TOrCs) using low pressure (LP)-UV/H2O2 advanced oxidation process (AOP), engaged with online sensor-based monitoring system. Thirty-nine TOrCs were evaluated in two distinct secondary wastewater effluents in terms of estimated photochemical reactivity, as a function of the rate constants of UV direct photolysis (kUV) and hydroxyl radical (OH) oxidation (kOH). The selected eighteen TOrCs were classified into three groups that served as indicator compounds: Group 1 for photo-susceptible TOrCs but with minor degradation by OH oxidation (diclofenac, fluoxetine, iohexol, iopamidol, iopromide, simazine and sulfamethoxazole); Group 2 for TOrCs susceptible to both direct photolysis and OH oxidation (benzotriazole, diphenhydramine, ibuprofen, naproxen and sucralose); and Group 3 for photo-resistant TOrCs showing dominant degradation by OH oxidation (atenolol, carbamazepine, DEET, gemfibrozil, primidone and trimethoprim). The results indicate that TOC (optical-based measurement), UVA254 or UVT254 (UV absorbance or transmittance at 254 nm), and total fluorescence can all be used as suitable on-line organic surrogate parameters to predict the attenuation of TOrCs. Furthermore, the automated real-time monitoring via on-line surrogate sensors and equipped with the developed degradation profiles between sensor response and a group of TOrCs removal can provide a diagnostic tool for process control during advanced treatment of reclaimed waters.

  19. The role of boron nitride nanotube as a new chemical sensor and potential reservoir for hydrogen halides environmental pollutants

    Science.gov (United States)

    Yoosefian, Mehdi; Etminan, Nazanin; Moghani, Maryam Zeraati; Mirzaei, Samaneh; Abbasi, Shima

    2016-10-01

    Density functional theory (DFT) studies on the interaction of hydrogen halides (HX) environmental pollutants and the boron nitride nanotubes (BNNTs) have been reported. To exploit the possibility of BNNTs as gas sensors, the adsorption of hydrogen fluoride (HF), hydrogen chloride (HCl) and hydrogen bromide (HBr) on the side wall of armchair (5,5) boron nitride nanotubes have been investigated. B3LYP/6-31G (d) level were used to analyze the structural and electronic properties of investigate sensor. The adsorption process were interpreted by highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO), quantum theory of atoms in molecules (QTAIM), natural bond orbital (NBO) and molecular electrostatic potential (MEP) analysis. Topological parameters of bond critical points have been used to calculate as measure of hydrogen bond (HB) strength. Stronger binding energy, larger charge transfer and charge density illustrate that HF gas possesses chemisorbed adsorption process. The obtained results also show the strongest HB in HF/BNNT complex. We expect that results could provide helpful information for the design of new BNNTs based sensing devices.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-06-01

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

  1. Plasma-enhanced chemical vapor deposited silicon oxynitride films for optical waveguide bridges for use in mechanical sensors

    DEFF Research Database (Denmark)

    Storgaard-Larsen, Torben; Leistiko, Otto

    1997-01-01

    In this paper the influence of RF power, ammonia flow, annealing temperature, and annealing time on the optical and mechanical properties of plasma-enhanced chemically vapor deposited silicon oxynitride films, is presented. A low refractive index (1.47 to 1.48) film having tensile stress has been...

  2. Microcantilever sensor

    Science.gov (United States)

    Thundat, T.G.; Wachter, E.A.

    1998-02-17

    An improved microcantilever sensor is fabricated with at least one microcantilever attached to a piezoelectric transducer. The microcantilever is partially surface treated with a compound selective substance having substantially exclusive affinity for a targeted compound in a monitored atmosphere. The microcantilever sensor is also provided with a frequency detection means and a bending detection means. The frequency detection means is capable of detecting changes in the resonance frequency of the vibrated microcantilever in the monitored atmosphere. The bending detection means is capable of detecting changes in the bending of the vibrated microcantilever in the monitored atmosphere coactively with the frequency detection means. The piezoelectric transducer is excited by an oscillator means which provides a signal driving the transducer at a resonance frequency inducing a predetermined order of resonance on the partially treated microcantilever. Upon insertion into a monitored atmosphere, molecules of the targeted chemical attach to the treated regions of the microcantilever resulting in a change in oscillating mass as well as a change in microcantilever spring constant thereby influencing the resonant frequency of the microcantilever oscillation. Furthermore, the molecular attachment of the target chemical to the treated regions induce areas of mechanical strain in the microcantilever consistent with the treated regions thereby influencing microcantilever bending. The rate at which the treated microcantilever accumulates the target chemical is a function of the target chemical concentration. Consequently, the extent of microcantilever oscillation frequency change and bending is related to the concentration of target chemical within the monitored atmosphere. 16 figs.

  3. Electrochemical evaluation of chemical selectivity of glutamate receptor ion channel proteins with a multi-channel sensor.

    Science.gov (United States)

    Sugawara, M; Hirano, A; Rehák, M; Nakanishi, J; Kawai, K; Sato, H; Umezawa, Y

    1997-01-01

    A new method for evaluating chemical selectivity of agonists towards receptor ion channel proteins is proposed by using glutamate receptor (GluR) ion channel proteins and their agonists N-methyl-D-aspartic acid (NMDA), L-glutamate, and (2S, 3R, 4S) isomer of 2-(carboxycyclopropyl)glycine (L-CCG-IV). Integrated multi-channel currents, corresponding to the sum of total amount of ions passed through the multiple open channels, were used as a measure of agonists' selectivity to recognize ion channel proteins and induce channel currents. GluRs isolated from rat synaptic plasma membranes were incorporated into planar bilayer lipid membranes (BLMs) formed by the folding method. The empirical factors that affect the selectivity were demonstrated: (i) the number of GluRs incorporated into BLMs varied from one membrane to another; (ii) each BLM contained different subtypes of GluRs (NMDA and/or non-NMDA subtypes); and (iii) the magnitude of multi-channel responses induced by L-glutamate at negative applied potentials was larger than at positive potentials, while those by NMDA and L-CCG-IV were linearly related to applied potentials. The chemical selectivity among NMDA, L-glutamate and L-CCG-IV for NMDA subtype of GluRs was determined with each single BLM in which only NMDA subtype of GluRs was designed to be active by inhibiting the non-NMDA subtypes using a specific antagonist DNQX. The order of selectivity among the relevant agonists for the NMDA receptor subtype was found to be L-CCG-IV > L-glutamate > NMDA, which is consistent with the order of binding affinity of these agonists towards the same NMDA subtypes. The potential use of this approach for evaluating chemical selectivity towards non-NMDA receptor subtypes of GluRs and other receptor ion channel proteins is discussed.

  4. Immobilization of redox mediators on functionalized carbon nanotube: A material for chemical sensor fabrication and amperometric determination of hydrogen peroxide

    Indian Academy of Sciences (India)

    D R Shobha Jeykumari; S Senthil Kumar; S Sriman Narayanan

    2005-10-01

    Chemical functionalization of single-walled carbon nanotubes with redox mediators, namely, toluidine blue and thionin have been carried out and the performance of graphite electrode modified with functionalized carbon nanotubes is described. Mechanical immobilization of functionalized single-walled nanotube (SWNT) on graphite electrode was achieved by gently rubbing the electrode surface on carbon nanotubes supported on a glass slide. The electrochemical behaviour of the modified electrodes was investigated by cyclic voltammetry. The SWNT-modified electrodes showed excellent electrocatalytic effect for the reduction of hydrogen peroxide. A decrease in overvoltage was observed as well as an enhanced peak current compared to a bare graphite electrode for the reduction of hydrogen peroxide. The catalytic current was found to be directly proportional to the amount of hydrogen peroxide taken.

  5. Miniature sensor suitable for electronic nose applications

    DEFF Research Database (Denmark)

    Pinnaduwage, L. A.; Gehl, A. C.; Allman, S. L.;

    2007-01-01

    A major research effort has been devoted over the years for the development of chemical sensors for the detection of chemical and explosive vapors. However, the deployment of such chemical sensors will require the use of multiple sensors probably tens of sensors in a sensor package to achieve sel...... microcantilevers. The sensor can detect parts-per-trillion concentrations of DMMP within 10 s exposure times. The small size of the sensor makes it ideally suited for electronic nose applications. © 2007 American Institute of Physics....

  6. Smart sensors and systems

    CERN Document Server

    Kyung, Chong-Min; Yasuura, Hiroto; Liu, Yongpan

    2015-01-01

     This book describes for readers technology used for effective sensing of our physical world and intelligent processing techniques for sensed information, which are essential to the success of Internet of Things (IoTs).  The authors provide a multidisciplinary view of sensor technology from MEMS, biological, chemical, and electrical domains and showcase smart sensor systems in real applications including smart home, transportation, medical, environmental, agricultural, etc.  Unlike earlier books on sensors, this book will provide a “global” view on smart sensors covering abstraction levels from device, circuit, systems, and algorithms.  .

  7. Process monitoring with disposable chemical sensors fit in the framework of process analysis technology (PAT) for innovative pharmaceutical development and quality assurance.

    Science.gov (United States)

    Spichiger, Stefan; Spichiger-Keller, Ursula E

    2010-01-01

    The innovative principle of enzymatic sensors applied to monitor the feeding process in disposable bioreactors is described. Innovative is the type of enzyme immobilized within the 'paste' to monitor L-glutamate. Innovative is the application of the miniaturized disposable sensor developed at C-CIT AG for continuous monitoring. The sensor allows the amount of the digested nutrient to be estimated from the amperometric signal. Innovative is the wireless signal transduction between the sensor mounted to the bioreactor and the signal receiver. An example of a process control run is given and, also, the biocompatibility and the specifications of the biosensors. The comparison of results evaluated by different analytical methods is discussed.

  8. Sensor technology foresight

    DEFF Research Database (Denmark)

    Andersen, Per Dannemand; Jørgensen, Birte Holst; Rasmussen, Birgitte

    2001-01-01

    heavily impacted by new sensor technology. It also appears that new sensor technology will affect food processing and the environment sector. Some impact is made on sectors such as agriculture, chemical engineering, domestic and otherappliances, security and defence, transport, and energy. Less impact...... is made in sectors such as construction/housing, wood/textile, IT/communication, and metal and plastic processing. The survey does not challenge the generally accepted perception thatthe transport sector also in a 10 year future will be a driving force in developing new sensor technology.......The Sensor Technology Center A/S (STC) in co-operation with Risoe National Laboratory has carried out a sensor technology foresight in order to strengthen a strategic outlook on sensor technology. The technology foresight (with a timeframe of 2000 to2015) has been performed in the period October...

  9. Modeling of soft sensor for chemical process%化工过程软测量建模方法研究进展

    Institute of Scientific and Technical Information of China (English)

    曹鹏飞; 罗雄麟

    2013-01-01

    软测量仪表是解决化工过程中质量变量难以实时测量的重要手段.软测量仪表的核心问题是软测量建模.阐述了软测量建模与辨识和非线性建模的关系;质量变量和易测变量的动态关系存在于增量之间,辨识模型依赖于增量数据,软测量建模则是依赖于实测变量数据来获取这个动态关系;非线性建模建立了变量间的静态关系,忽略了对象动态特性,而软测量建模要兼顾对动态特性的表征.随着人们对过程特性的认识加深,软测量建模方法不断发展,经历了从机理建模到数据驱动建模,从线性建模到非线性建模,从静态建模到动态建模的过程.详细讨论了软测量建模的发展过程,众多建模方法的优缺点及适用情况和现在建模的热点,最后对软测量建模方法进行了总体展望.%In the commercial chemical process, many primary product variables cannot be measured online, and soft sensor is an important means to solve this problem. Soft sensing modeling is the core issue of soft sensor. The relationship between soft sensing modeling and identification and nonlinear modeling is presented. The dynamic relationship between quality variables and variables that are easy to measure exists between the increments, and identification depends on incremental data, while soft sensing modeling depends on the measured data to get the relationship. Nonlinear modeling establishes the static relationship between these variables, ignoring the dynamic characteristics, which soft sensing modeling should take into account. With deeper understanding of the chemical process properties, the types and structures of soft sensing model have undergone a great change in the last decades, and soft sensing modeling method evolves from mechanism modeling to data-driven modeling, from linear modeling to nonlinear modeling, and from static modeling to dynamic modeling. The development of the soft sensing modeling method is

  10. Sensors and low power signal processing

    CERN Document Server

    Islam, Syed Kamrul

    2010-01-01

    Offers a general overview of a sensor's working principle and a discussion of various sensor technologies including chemical, electro-chemical and MEMS based sensors. This book includes a discussion on design challenges associated with low-power analog circuits and the schemes to overcome them.

  11. Ammonia sensors and their applications - a review

    NARCIS (Netherlands)

    Timmer, Björn; Olthuis, Wouter; Berg, van den Albert

    2005-01-01

    Many scientific papers have been written concerning gas sensors for different sensor applications using several sensing principles. This review focuses on sensors and sensor systems for gaseous ammonia. Apart from its natural origin, there are many sources of ammonia, like the chemical industry or i

  12. 低沸点化学物质在无源轿车轮胎温度传感器中的应用%Application of Low-boiling Point Chemicals in Car Tire's Passive Temperature Sensor

    Institute of Scientific and Technical Information of China (English)

    张健伟; 赫广田; 董群; 王鉴; 胡林杰

    2012-01-01

    利用低沸点化学物质具有较高的饱和蒸汽压的特性,设计了一种无源轿车轮胎温度监测系统.系统中的温度传感器是将温度变化通过低沸点化学物质的饱和蒸汽压信号转变为磁铁的位移信号,再利用线性霍尔传感器检测位移信号,实现对轮胎内温度的实时监测.低沸点化学物质是温度传感器的核心之一,结合轮胎温度报警的实际条件,通过考察不同低沸点物质的饱和蒸汽压随温度和压力的变化规律,并考虑化学物质使用的安全性,最终确定了该温度传感器中所适用的感温物质.%Considering the fact that low-boiling point chemical substance has higher saturated steam pressure, a car tire' s temperature monitoring system was designed to have tire' s temperature change translated to the magnet displacement signals through saturated steam pressure change of low-boiling point chemical substance in temperature sensor, and then to have the displacement signals detected with liner Hall element and the tire temperature monitored in real time. The low-boiling point chemical substance means important to the temperature sensor, having the rules that saturated steam pressure of different low-boiling point chemicals varies with temperature and pressure studied, and the conditions of tire temperature alarm and chemical substance security considered, the best temperature sensitive substance for passive temperature sensor was determined.

  13. Chemical, physical, and other data collected using bottle, BT, current meter, MBT, meteorological sensors, and secchi disk casts in the North Pacific Ocean as part of the California Cooperative Fisheries Investigation (CALCOFI) project, from 01 January to 04 December 1968 (NODC Accession 7100603)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chemical, physical, and other data were collected using bottle, BT, current meter, MBT, meteorological sensors, and secchi disk casts from January 1, 1968 to...

  14. A (Bio-Chemical Field-Effect Sensor with Macroporous Si as Substrate Material and a SiO2 / LPCVD-Si3N4 Double Layer as pH Transducer

    Directory of Open Access Journals (Sweden)

    Hans Lüth

    2002-01-01

    Full Text Available Macroporous silicon has been etched from n-type Si, using a vertical etching cell where no rear side contact on the silicon wafer is necessary. The resulting macropores have been characterised by means of Scanning Electron Microscopy (SEM. After etching, SiO2 was thermally grown on the top of the porous silicon as an insulating layer and Si3N4 was deposited by means of Low Pressure Chemical Vapour Deposition (LPCVD as transducer material to fabricate a capacitive pH sensor. In order to prepare porous biosensors, the enzyme penicillinase has been additionally immobilised inside the porous structure. Electrochemical measurements of the pH sensor and the biosensor with an Electrolyte/Insulator/Semiconductor (EIS structure have been performed in the Capacitance/Voltage (C/V and Constant capacitance (ConCap mode.

  15. Multilayer fiber optic chemical sensors employing organically modified SiO2 and mixed TiO2/SiO2 sol gel membranes

    Science.gov (United States)

    Nivens, Delana A.; Schiza, Maria V.; Angel, S. M.

    1997-05-01

    Fiber-optic sensors have been developed that incorporate multi-layer organically modified silica sol-gel membranes. pH sensors use a single layer hydrophilic organo-silica sol-gel membrane with a covalently attached pH sensitive dye, hydroxypyrene trisulfonic acid. The hydrophilic coating is made by copolymerizing silanol-terminated polydimethylsiloxane and tetraethylorthosilicate with 3-aminopropyltriethoxysilane. Unlike previous methods, which use acid as a catalyst, we have found that a base catalyst produces optically transparent gels. The sol-gel coated sensors are simple to make and require drying and aging times of as little as one day. Sensors made using these gels exhibit very good long-term stability, fast response times and no dye leaching. pCO2 sensors were fabricated using the same pH sensitive sol-gel layer overcoated with a hydrophobic high organic content sol- gel membrane. The response of the pH and pCO2 sensors is very fast due to the high porosity of the sol-gel membranes. Although in-situ sensors have been described for a number of organic and inorganic species, many volatile organochloride compounds (VOCs), such as perchloroethylene (PCE) and trichloroethylene (TCE), have been difficult to measure using current fiber-optic sensor transduction schemes. One of the optical sensors described here is a multilayer (3-4) sol-gel system that incorporates a TiO2/SiO2 membrane to degrade VOCs into smaller, detectable products. Upon exposure to UV light, TiO2, a semiconductor with a bandgap of 3.2 eV, produces highly reactive electron-hole pairs that are capable of photodegrading most organic compounds. The VOCs mentioned above are sensitive to degradative oxidation on TiO2 surfaces. During photodegradation of VOCs a number of products are formed including H+, HCl, CO2 and a number of smaller hydrocarbons. These products are produced in the TiO2 membrane and on TiO2 surfaces and the products diffuse into the nearby indicator membrane where they are

  16. Organic semiconductors in sensor applications

    CERN Document Server

    Malliaras, George; Owens, Róisín

    2008-01-01

    Organic semiconductors offer unique characteristics such as tunability of electronic properties via chemical synthesis, compatibility with mechanically flexible substrates, low-cost manufacturing, and facile integration with chemical and biological functionalities. These characteristics have prompted the application of organic semiconductors and their devices in physical, chemical, and biological sensors. This book covers this rapidly emerging field by discussing both optical and electrical sensor concepts. Novel transducers based on organic light-emitting diodes and organic thin-film transistors, as well as systems-on-a-chip architectures are presented. Functionalization techniques to enhance specificity are outlined, and models for the sensor response are described.

  17. Reversible NO2 Optical Fiber Chemical Sensor Based on LuPc2 Using Simultaneous Transmission of UV and Visible Light.

    Science.gov (United States)

    Bueno, Antonio; Lahem, Driss; Caucheteur, Christophe; Debliquy, Marc

    2015-04-27

    In this paper, an NO2 optical fiber sensor is presented for pollution monitoring in road traffic applications. This sensor exploits the simultaneous transmission of visible light, as a measurement signal, and UV light, for the recovery of the NO2 sensitive materials. The sensor is based on a multimode fiber tip coated with a thin film of lutetium bisphthalocyanine (LuPc2). The simultaneous injection of UV light through the fiber is an improvement on the previously developed NO2 sensors and allows the simplification of the sensor head, rendering the external UV illumination of the film unnecessary. Coatings of different thicknesses were deposited on the optical fiber tips and the best performance was obtained for a 15 nm deposited thickness, with a sensitivity of 5.02 mV/ppm and a resolution of 0.2 ppb in the range 0-5 ppm. The response and recovery times are not dependent on thickness, meaning that NO2 does not diffuse completely in the films.

  18. Ambient Sensors

    NARCIS (Netherlands)

    Börner, Dirk; Specht, Marcus

    2014-01-01

    This software sketches comprise two custom-built ambient sensors, i.e. a noise and a movement sensor. Both sensors measure an ambient value and process the values to a color gradient (green > yellow > red). The sensors were built using the Processing 1.5.1 development environment. Available under th

  19. Particulate matter sensor with a heater

    Science.gov (United States)

    Hall, Matthew

    2011-08-16

    An apparatus to detect particulate matter. The apparatus includes a sensor electrode, a shroud, and a heater. The electrode measures a chemical composition within an exhaust stream. The shroud surrounds at least a portion of the sensor electrode, exclusive of a distal end of the sensor electrode exposed to the exhaust stream. The shroud defines an air gap between the sensor electrode and the shroud and an opening toward the distal end of the sensor electrode. The heater is mounted relative to the sensor electrode. The heater burns off particulate matter in the air gap between the sensor electrode and the shroud.

  20. Electrochemical Sensors for Clinic Analysis

    OpenAIRE

    Guang Li; Jianming Zhang; Hui Xu; You Wang

    2008-01-01

    Demanded by modern medical diagnosis, advances in microfabrication technology have led to the development of fast, sensitive and selective electrochemical sensors for clinic analysis. This review addresses the principles behind electrochemical sensor design and fabrication, and introduces recent progress in the application of electrochemical sensors to analysis of clinical chemicals such as blood gases, electrolytes, metabolites, DNA and antibodies, including basic and applied research. Minia...

  1. Sensor Technologies on Flexible Substrates

    Science.gov (United States)

    Koehne, Jessica

    2016-01-01

    NASA Ames has developed sensor technologies on flexible substrates integrated into textiles for personalized environment monitoring and human performance evaluation. Current technologies include chemical sensing for gas leak and event monitoring and biological sensors for human health and performance monitoring. Targeted integration include next generation EVA suits and flexible habitats.

  2. Large pressure range hydrogen sensor

    NARCIS (Netherlands)

    Boelsma, C.; Dam, B.

    2015-01-01

    The present invention relates to a thin-film sensor, to a method for producing a thin-film device, to an alloy for use in an optical sensing layer, to use of an alloy for sensing a chemical species such as hydrogen, to a sensor, to an apparatus for detecting hydrogen, to an electro-magnetic transfor

  3. Graphene based piezoresistive pressure sensor

    NARCIS (Netherlands)

    Zhu, S.E.; Ghatkesar, M.K.; Zhang, C.; Janssen, G.C.A.M.

    2013-01-01

    We present a pressure sensor based on the piezoresistive effect of graphene. The sensor is a 100 nm thick, 280 μm wide square silicon nitride membrane with graphene meander patterns located on the maximum strain area. The multilayer, polycrystalline graphene was obtained by chemical vapor deposition

  4. Extended range chemical sensing apparatus

    Science.gov (United States)

    Hughes, Robert C.; Schubert, W. Kent

    1994-01-01

    An apparatus for sensing chemicals over extended range of concentrations. In particular, first and second sensors each having separate, but overlapping ranges for sensing concentrations of hydrogen are provided. Preferably, the first sensor is a MOS solid state device wherein the metal electrode or gate is a nickel alloy. The second sensor is a chemiresistor comprising a nickel alloy.

  5. Time-domain fiber loop ringdown sensor and sensor network

    Science.gov (United States)

    Kaya, Malik

    Optical fibers have been mostly used in fiber optic communications, imaging optics, sensing technology, etc. Fiber optic sensors have gained increasing attention for scientific and structural health monitoring (SHM) applications. In this study, fiber loop ringdown (FLRD) sensors were fabricated for scientific, SHM, and sensor networking applications. FLRD biosensors were fabricated for both bulk refractive index (RI)- and surface RI-based DNA sensing and one type of bacteria sensing. Furthermore, the effect of glucose oxidase (GOD) immobilization at the sensor head on sensor performance was evaluated for both glucose and synthetic urine solutions with glucose concentration between 0.1% and 10%. Detection sensitivities of the glucose sensors were achieved as low as 0.05%. For chemical sensing, heavy water, ranging from 97% to 10%, and several elemental solutions were monitored by using the FLRD chemical sensors. Bulk index-based FLRD sensing showed that trace elements can be detected in deionized water. For physical sensing, water and cracking sensors were fabricated and embedded into concrete. A partially-etched single-mode fiber (SMF) was embedded into a concrete bar for water monitoring while a bare SMF without any treatment was directly embedded into another concrete bar for monitoring cracks. Furthermore, detection sensitivities of water and crack sensors were investigated as 10 ml water and 0.5 mm surface crack width, respectively. Additionally fiber loop ringdown-fiber Bragg grating temperature sensors were developed in the laboratory; two sensor units for water, crack, and temperature sensing were deployed into a concrete cube in a US Department of Energy test bed (Miami, FL). Multi-sensor applications in a real concrete structure were accomplished by testing the six FLRD sensors. As a final stage, a sensor network was assembled by multiplexing two or three FLRD sensors in series and parallel. Additionally, two FLRD sensors were combined in series and

  6. Magnetic Resonance Sensors

    Directory of Open Access Journals (Sweden)

    Robert H. Morris

    2014-11-01

    Full Text Available Magnetic Resonance finds countless applications, from spectroscopy to imaging, routinely in almost all research and medical institutions across the globe. It is also becoming more frequently used for specific applications in which the whole instrument and system is designed for a dedicated application. With beginnings in borehole logging for the petro-chemical industry Magnetic Resonance sensors have been applied to fields as varied as online process monitoring for food manufacture and medical point of care diagnostics. This great diversity is seeing exciting developments in magnetic resonance sensing technology published in application specific journals where they are often not seen by the wider sensor community. It is clear that there is enormous interest in magnetic resonance sensors which represents a significant growth area. The aim of this special edition of Sensors was to address the wide distribution of relevant articles by providing a forum to disseminate cutting edge research in this field in a single open source publication.[...

  7. Using optoelectronic sensors in the system PROTEUS

    Science.gov (United States)

    Zyczkowski, M.; Szustakowski, M.; Ciurapinski, W.; Piszczek, M.

    2010-10-01

    The paper presents the concept of optoelectronic devices for human protection in rescue activity. The system consists of an ground robots with predicted sensor. The multisensor construction of the system ensures significant improvement of security of using on-situ like chemical or explosive sensors. The article show a various scenario of use for individual sensor in system PROTEUS.

  8. Metamaterial Sensors

    Directory of Open Access Journals (Sweden)

    Jing Jing Yang

    2013-01-01

    Full Text Available Metamaterials have attracted a great deal of attention due to their intriguing properties, as well as the large potential applications for designing functional devices. In this paper, we review the current status of metamaterial sensors, with an emphasis on the evanescent wave amplification and the accompanying local field enhancement characteristics. Examples of the sensors are given to illustrate the principle and the performance of the metamaterial sensor. The paper concludes with an optimistic outlook regarding the future of metamaterial sensor.

  9. Attention Sensor

    NARCIS (Netherlands)

    Börner, Dirk; Kalz, Marco; Specht, Marcus

    2014-01-01

    This software sketch was used in the context of an experiment for the PhD project “Ambient Learning Displays”. The sketch comprises a custom-built attention sensor. The sensor measured (during the experiment) whether a participant looked at and thus attended a public display. The sensor was built us

  10. 海洋环境监测中的光纤化学/生物传感技术%Study on the Fiber Optic Chemical Sensors and Biosensors Applied to Monitoring for Environmental Contaminants in Seawater

    Institute of Scientific and Technical Information of China (English)

    庄峙厦; 李伟; 陈曦; 孙大海; 王小如

    2001-01-01

    Rapid and continuous detection of environmental contaminants in effluents and waterways is important for protecting natural environments and public health, and for managing waster treatment systems. Some novel circulatory system for on-line monitoring of dissolved oxygen, pH, humidity and pollutants that make use of fiber-optic chemical sensors and biosensors are presented. Some useful approach have been employing chemical and bioluminescent reporter systems that involve whole molecular probes and bioluminescent microbes which provide rapid and visible responses to dissolved oxygen, pH, humidity and the presence of harmful chemicals, including heavy metal ions and petrochemical industry waters. Coupling such chemical and biological detection systems with fiber-optic chemical sensors and biosensors for environmental monitoring combines rapid response times, low costs and improved reproducibility.%通过光纤溶解氧、pH、湿度等化学传感探头及发光菌水质毒性监测生物传感探头的研制,开发出了一类能用于环境监测的新型传感器.其创新之处在于传感探头的设计与包装,以及数种可逆性、选择性、稳定性、使用寿命、响应时间、灵敏度等响应特性具佳的化学及生物传感膜的配方和制作技术.利用这些技术,通过对光纤探头的设计与包装,可以实现在现场及实验室模拟条件下对样品的选择性检测.研制的传感器能广泛应用于海洋污染调查、内河水质评价、水产养殖、工矿企业水气排污自检等诸多方面.

  11. Chemical sensor and field screening technology development: Downhole photoionization detection of volatile organic compounds. Topical report, March 1, 1995--March 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Schabron, J.F.; Rovani, J.F. Jr.; Moore, D.F.

    1998-12-31

    Western Research Institute conducted a study to define the various parameters that need to be considered in the design and use of a downhole submersible photoionization detector (PID) probe to measure volatile organic compounds (VOCs). Detector response under various conditions, including saturated humidity environments, temperature, and analyte concentration was studied. The relative responses for several VOC analytes were measured. The partitioning of VOCs between water and air was studied as a function of analyte concentration and temperature. The Henry`s law constant governing this partitioning represents an ideal condition at infinite dilution for a particular temperature. The results show that this partitioning is not ideal. Conditions resulting in apparent, practical deviations from Henry`s law include temperature and VOC concentration. Studies with membranes show that membranes that allow passage of VOCs also allow some passage of water vapor. A membrane could play a useful role in protecting the sensor from direct contact with liquid water down hole. A porous poly(tetrafluoroethylene) (PTFE) membrane allows for a rapid passage of VOCs. The rate of diffusion to the sensor with or without a membrane might be a limiting factor for rapid measurements. Various means of mixing may need to be considered.

  12. A high-sensitivity chemical sensor based on titania coated optical-fiber long period grating for ammonia sensing in water

    Science.gov (United States)

    Tiwari, D.; James, S. W.; Tatam, R. P.; Korposh, S.; Lee, S. W.

    2015-07-01

    Two highly sensitive ammonia sensors, formed by depositing coatings composed of titanium dioxide (TiO2) onto the cladding of an optical fibre sensing platform, are evaluated. A long period grating (LPG) of period 111 μm was fabricated in the core of an optical fibre so that the LPG operates at or near the phase matching turning point (PMTP). The first coating that was investigated was composed of TiO2 nanoparticles deposited by liquid phase deposition. The sensor showed high sensitivity and allowed low concentrations of ammonia in water (0.01 ppm) to be detected with a response time of less than 60 sec. The second coating was composed of TiO2 with subsequent layers of poly (allyamine hydrochloride) (PAH), and SiO2 nanospheres infused with a sensitive element composed of porphine. The ammonia adsorption to the porphine compound led to the changes in the LPG's transmission spectrum and allowed 0.1 ppm of ammonia in water to be detected with a response time of less than 60 sec.

  13. Catalytic Membrane Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Boyle, T.J.; Brinker, C.J.; Gardner, T.J.; Hughes, R.C.; Sault, A.G.

    1998-12-01

    The proposed "catalytic membrane sensor" (CMS) was developed to generate a device which would selectively identify a specific reagent in a complex mixture of gases. This was to be accomplished by modifying an existing Hz sensor with a series of thin films. Through selectively sieving the desired component from a complex mixture and identifying it by decomposing it into Hz (and other by-products), a Hz sensor could then be used to detect the presence of the select component. The proposed "sandwich-type" modifications involved the deposition of a catalyst layered between two size selective sol-gel layers on a Pd/Ni resistive Hz sensor. The role of the catalyst was to convert organic materials to Hz and organic by-products. The role of the membraneo was to impart both chemical specificity by molecukir sieving of the analyte and converted product streams, as well as controlling access to the underlying Pd/Ni sensor. Ultimately, an array of these CMS elements encompassing different catalysts and membranes were to be developed which would enable improved selectivity and specificity from a compiex mixture of organic gases via pattern recognition methodologies. We have successfully generated a CMS device by a series of spin-coat deposited methods; however, it was determined that the high temperature required to activate the catalyst, destroys the sensor.

  14. Sensor web

    Science.gov (United States)

    Delin, Kevin A. (Inventor); Jackson, Shannon P. (Inventor)

    2011-01-01

    A Sensor Web formed of a number of different sensor pods. Each of the sensor pods include a clock which is synchronized with a master clock so that all of the sensor pods in the Web have a synchronized clock. The synchronization is carried out by first using a coarse synchronization which takes less power, and subsequently carrying out a fine synchronization to make a fine sync of all the pods on the Web. After the synchronization, the pods ping their neighbors to determine which pods are listening and responded, and then only listen during time slots corresponding to those pods which respond.

  15. Gas Sensor

    KAUST Repository

    Luebke, Ryan

    2015-01-22

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

  16. Sensores ópticos com detecção no infravermelho próximo e médio Near and mid infrared optical sensors

    Directory of Open Access Journals (Sweden)

    Kássio M. G. Lima

    2009-01-01

    Full Text Available Optical chemical sensors with detection in the near and mid infrared region are reviewed. Fundamental concepts of infrared spectroscopy and optical chemical sensors are briefly described, before presenting some aspects on optical chemical sensors, such as synthesis of NIR and IR reagents, preparation of new materials as well as application in determinations of species of biological, industrial and environmental importance.

  17. Smart Sensors

    Science.gov (United States)

    Corsi, C.

    2007-01-01

    The term "Smart Sensors" refers to sensors which contain both sensing and signal processing capabilities with objectives ranging from simple viewing to sophisticated remote sensing, surveillance, search/track, weapon guidance, robotics, perceptronics and intelligence applications. Recently this approach is achieving higher goals by a new and revolutionary sensors concept which introduced inside the sensor some of the basic functions of living eyes, such as dynamic stare, non-uniformity compensation, spatial and temporal filtering. New objectives and requirements are presented for this type of new infrared smart sensor systems. This paper is concerned with the front end of FPA microbolometers processing, namely, the enhancement of target-to-noise ratio by background clutter suppression and the improvement in target detection by "smart" and pattern correlation thresholding.

  18. Pathogen Sensors

    Directory of Open Access Journals (Sweden)

    Joseph Irudayaraj

    2009-10-01

    Full Text Available The development of sensors for detecting foodborne pathogens has been motivated by the need to produce safe foods and to provide better healthcare. However, in the more recent times, these needs have been expanded to encompass issues relating to biosecurity, detection of plant and soil pathogens, microbial communities, and the environment. The range of technologies that currently flood the sensor market encompass PCR and microarray-based methods, an assortment of optical sensors (including bioluminescence and fluorescence, in addition to biosensor-based approaches that include piezoelectric, potentiometric, amperometric, and conductometric sensors to name a few. More recently, nanosensors have come into limelight, as a more sensitive and portable alternative, with some commercial success. However, key issues affecting the sensor community is the lack of standardization of the testing protocols and portability, among other desirable elements, which include timeliness, cost-effectiveness, user-friendliness, sensitivity and specificity. [...

  19. Sensor yarns for real-time in situ detection of damage behavior for the purpose of structural health monitoring of textile-reinforced thermoset composites: development of a continuous wet-chemical silvering process for high-performance filament yarn

    Science.gov (United States)

    Onggar, T.; Häntzsche, E.; Nocke, A.; Hund, R. D.; Cherif, Ch

    2017-04-01

    High-performance textile yarns such as glass filament (GF) yarn will be used as the base material for the development of sensor yarns because glass filament yarns offer both high tensile strengths and moduli of elasticity, as well as high melting temperatures and elongation. A new continuous wet-chemical metallization process has been developed for GF yarns on a laboratory scale to achieve special properties such as electrical conductivity. The aim of the work is to develop a continuous wet-chemical silver plating process for the GF-filament yarn in order to achieve electrical conductivity on the GF-surface. The process was carried out continuously in order to metallize the GF, which is sensitive to the shear force. A homogeneous, completely covered and adhered silver layer on the GF yarn surfaces was obtained by the application of this technology. The surface morphology was been determined by light and scanning electron microscopy to assess the silver layer properties such as structure, homogeneity, and cracking. The chemical structure of the surfaces was analyzed by means of energy dispersive x-ray spectroscopy. For structural analysis, GF yarns were investigated using a Fourier transform infrared spectrometer. The dispersive and polar component of the surface energy of the sized and silvered GF yarn was measured by using a single fiber Tensiometer K100. The silver layer thickness and the silver content were determined after the metallization. Textile physical tests of the tensile strength, elasticity modulus, elongation at break, and yarn fineness of the single GF yarns as well as GF bundle were carried out.

  20. Metaniche session 2016: Tailor-made sensors for rapid Therapeutic Drug Monitoring –Interactions between Biomaterial Physicists, Chemical Engineers and Clinicians for successful translation of technologies in Healthcare

    Directory of Open Access Journals (Sweden)

    Yoshimi Y

    2016-11-01

    Full Text Available The Metaniche session is an academic session conducted as a part of Nichi-In Centre for Regenerative Medicine (NCRM’s novel Initiatives' Conclave in Healthcare Every year (NICHE, the ‘NCRM NICHE’ organized every year in the month of October by Nichi-In Centre for Regenerative Medicine (NCRM, an Indo-Japan academic Institute based at Chennai, India. The Metaniche session aims to bring together the realms of Physics, Chemistry and Biology by portraying inventions or discoveries in physical and chemical sciences which are in the pipeline with high application potential in biology and healthcare. The Metaniche session-2016, held on 22nd October, 2016 in Chennai, India was on the application of biomaterial-based sensors for application in rapid therapeutic drug monitoring (TDM systems. The session focussed on the role of biomaterials in medicine giving an overview and history of the evolution of biomaterials to suit the growing needs in medicine, followed by emphasizing the need for rapid TDM systems. The final part portrayed the development of tailor-made sensors for rapid TDM using molecularly imprinted polymers as given below. Biomaterials and Medicine It has been always medical practitioners coming first to identify the need to lead themselves and others towards the best therapy. When patient services emerged, the clinicians themselves were everybody. Dr Gibbon, when he did his first open heart case in 1950’s, he was the perfusionist and perhaps anaesthetist too. To get into its (bio materials, through a case study, let us take a review of a simple clinical procedure. Wound closure through suturing. Its tribology matrix highlighted below (Figure 1, sketches its journey, clinical demands, scientific solutions and biomaterials thereof. The bottom line, best is still (researched.

  1. Vacuum-deposited wave-guiding layers on STW resonators based on LiTaO(3) substrate as love wave sensors for chemical and biochemical sensing in liquids.

    Science.gov (United States)

    Barié, Nicole; Stahl, Ullrich; Rapp, Michael

    2010-05-01

    A promising approach to apply the Love wave concept to commercially available low-loss surface acoustic wave (SAW) devices of the type Murata SAF 380 is presented. Thin wave-guiding layers of variable thickness are coated on the piezoelectric substrate of the devices. Two different layer materials were used: sputtered SiO(2) and a new polymer in this field, paryleneC (poly-[2-chloro-p-xylylene]). Insertion loss, resonance frequency, frequency changes during protein precipitation and noise of the devices are discussed as a function of the thickness of the wave-guiding layer. It is demonstrated that the application of an optimized wave-guiding layer increases the sensitivity. When using SiO(2) as wave-guiding layer, an optimum layer thickness of 4 microm leads to a detection limit of 1.7 pg/mm(2). Therefore, the detection limit is improved by factor 7.7 as compared to uncoated SAW devices. Parylene-coated devices reach a detection limit of 2.9 pg/mm(2) at an optimum layer thickness of 0.5 microm. This corresponds to an improvement by factor 4.3. As the SAW devices used in this study are commercially available at low costs, applying appropriate wave-guiding layers permits an application as chemical or biochemical sensors with excellent sensitivities. Moreover, parylene-coated devices combine the sensitivity increase by excitation of Love waves with an excellent protective effect against corrosive attacks by the surrounding medium. Therefore, these sensors are most suitable for biosensing in conducting buffer solutions.

  2. Automotive sensors

    Science.gov (United States)

    Marek, Jiri; Illing, Matthias

    2003-01-01

    Sensors are an essential component of most electronic systems in the car. They deliver input parameters for comfort features, engine and emission control as well as for the active and passive safety systems. New technologies such as silicon micromachining play an important role for the introduction of these sensors in all vehicle classes. The importance and use of these sensor technologies in today"s automotive applications will be shown in this article. Finally an outlook on important current developments and new functions in the car will be given.

  3. Piezoceramic Sensors

    CERN Document Server

    Sharapov, Valeriy

    2011-01-01

    This book presents the latest and complete information about various types of piezosensors. A sensor is a converter of the measured physical size to an electric signal. Piezoelectric transducers and sensors are based on piezoelectric effects. They have proven to be versatile tools for the measurement of various processes. They are used for quality assurance, process control and for research and development in many different industries. In each area of application specific requirements to the parameters of transducers and sensors are developed. This book presents the fundamentals, technical des

  4. [A Fluorescent Chemical Sensor Based on MgAl-8-HQ LDH Composite Particle for the Selective Detection of Fe3+].

    Science.gov (United States)

    Yang, Lei; Yao, Qi; Yuan, Xue-hua; Yang, Yan-ling

    2015-03-01

    completely quenched, when [Fe3+] was 10(-3) mol x L(-1). When -log[Fe3+] was in 3 to 6, negative correlation function appeared between -log[Fe3+] and its fluorescence intensity, so it could implement fluorescence sensing detection for Fe3+ with high selectivity and sensitivity. According to the above research results, a new method of fluorescent and colorimetric dual sensor detection of Fe3+ by Mg4Al-8-HQ LDH particle was successfully established.

  5. Development Of Porous Glass Fiber Optic Sensors

    Science.gov (United States)

    Macedo, P. B.; Barkatt, Aa.; Feng, X.; Finger, S. M.; Hojaji, H.; Laberge, N.; Mohr, R.; Penafiel, M.; Saad, E.

    A method for producing rugged, continuous porous glass fiber optic sensors was developed. pH and temperature sensors based on this technology have been successfully produced. The sensor portion of the fiber is made porous by selective leaching of a specially formulated borosilicate glass fiber. This results in a strong, monolithic structure where the sensor portion of the fiber remains integrally attached to the rest of the fiber (which acts as a light pipe), essentially eliminating losses at the sensor-light pipe interface. Pore size in the sensor can be controllably varied by modifying heat treatment conditions, making these sensors suitable for chemical concentration measurements in liquids and gases. Appropriate dyes were chemically bonded by silanization to the large interior surface area of the porous sensors to produce the pH and temperature sensors. Cresol red and phenol red were used for pH and pinacyanol chloride was used for temperature sensing. The sensitivity of these devices can be controlled by varying the concentration of the chemically bonded dye and the length of the porous region. Optical absorbance measurements were made in the visible range. The tip of the sensors was coated with a thin, porous layer of gold to reflect the incident light, resulting in a double pass across the porous sensor. Experimental measurements were made over a pH range of 3 to 8 and a temperature range of 28-70 C. These porous glass fiber optic sensors were found to be rugged and reliable due to their monolithic structure and large interior surface area for attachment of active species. A broad range of sensors based on this technology could be developed by using different active species, such as enzymes and other biochemicals, which could be bonded to the interior surface of the porous glass sensor.

  6. Towards outperforming conventional sensor arrays with fabricated individual photonic vapour sensors inspired by Morpho butterflies

    Science.gov (United States)

    Potyrailo, Radislav A.; Bonam, Ravi K.; Hartley, John G.; Starkey, Timothy A.; Vukusic, Peter; Vasudev, Milana; Bunning, Timothy; Naik, Rajesh R.; Tang, Zhexiong; Palacios, Manuel A.; Larsen, Michael; Le Tarte, Laurie A.; Grande, James C.; Zhong, Sheng; Deng, Tao

    2015-09-01

    Combining vapour sensors into arrays is an accepted compromise to mitigate poor selectivity of conventional sensors. Here we show individual nanofabricated sensors that not only selectively detect separate vapours in pristine conditions but also quantify these vapours in mixtures, and when blended with a variable moisture background. Our sensor design is inspired by the iridescent nanostructure and gradient surface chemistry of Morpho butterflies and involves physical and chemical design criteria. The physical design involves optical interference and diffraction on the fabricated periodic nanostructures and uses optical loss in the nanostructure to enhance the spectral diversity of reflectance. The chemical design uses spatially controlled nanostructure functionalization. Thus, while quantitation of analytes in the presence of variable backgrounds is challenging for most sensor arrays, we achieve this goal using individual multivariable sensors. These colorimetric sensors can be tuned for numerous vapour sensing scenarios in confined areas or as individual nodes for distributed monitoring.

  7. Vibration sensors

    Science.gov (United States)

    Gupta, Amita; Singh, Ranvir; Ahmad, Amir; Kumar, Mahesh

    2003-10-01

    Today, vibration sensors with low and medium sensitivities are in great demand. Their applications include robotics, navigation, machine vibration monitoring, isolation of precision equipment & activation of safety systems e.g. airbags in automobiles. Vibration sensors have been developed at SSPL, using silicon micromachining to sense vibrations in a system in the 30 - 200 Hz frequency band. The sensing element in the silicon vibration sensor is a seismic mass suspended by thin silicon hinges mounted on a metallized glass plate forming a parallel plate capacitor. The movement of the seismic mass along the vertical axis is monitored to sense vibrations. This is obtained by measuring the change in capacitance. The movable plate of the parallel plate capacitor is formed by a block connected to a surrounding frame by four cantilever beams located on sides or corners of the seismic mass. This element is fabricated by silicon micromachining. Several sensors in the chip sizes 1.6 cm x 1.6 cm, 1 cm x 1 cm and 0.7 cm x 0.7 cm have been fabricated. Work done on these sensors, techniques used in processing and silicon to glass bonding are presented in the paper. Performance evaluation of these sensors is also discussed.

  8. Cooperative use of standoff and UAV sensors for CBRNE detection

    Science.gov (United States)

    Marinelli, William J.; Schmit, Thomas; Rentz Dupuis, Julia; Mulhall, Phil; Croteau, Philly; Manegold, David; Beshay, Manal; Lav, Marvin

    2015-05-01

    The defense of the US armed forces against chemical and biological (CB) attack is transitioning from a focus on standoff detection of these threats to the concept of Early Warning (EW). In this approach an array of dual-use and low-burden dedicated use sensor capabilities are used to replace longer-range single use sensors to detect a CB attack. In this paper we discuss the use of passive broadband thermal imaging to detect chemical vapor clouds as well as a developing suite of compact UAV-borne chemical and radiological sensors for the investigation of threats detected by these indirect approaches. The sensors include a colorimetric ammonia sensor, a chemical sensor based on ion mobility spectrometry, and a radiation detector based on gamma ray scintillation. The implementation and initial field tests of each of these sensor modalities is discussed and future plans for the further development of the capability is presented.

  9. Fibre-optic sensors in health care

    Science.gov (United States)

    Grazia Mignani, Anna; Baldini, Francesco

    1997-05-01

    Biomedical fibre-optic sensors are attractive for the measurement of physical, chemical and biochemical parameters and for spectral measurements directly performed on the patient. An overview of fibre-optic sensors for in vivo monitoring is given, with particular attention paid to the advantages that these sensors are able to offer in different application fields such as cardiovascular and intensive care, angiology, gastroenterology, ophthalmology, oncology, neurology, dermatology and dentistry.

  10. MEMS sensor technology

    Institute of Scientific and Technical Information of China (English)

    Jiang Zhuangde

    2012-01-01

    Since 1992 the author has led research group in Xi'an Jiaotong University to investigate and develop microelectro mechanical systems (MEMS) sensors, including pressure sensor, acceleration sensor, gas sensor, viscosity & density sensor, polymerase chain reaction (PCR) chip and integrated sensor etc. This paper introduces the technologies and research results related to MEMS sensors we achieved in the last 20 years.

  11. Graphene as a sensor material

    OpenAIRE

    Kochmann, Sven

    2014-01-01

    This thesis is concerned with the synthesis, characterization and utilization of (reduced) graphene oxide (chemically derived graphene) for sensor applications. The first chapter describes the history of graphene, classifies all members of the graphene family by convenient definitions, and outlines the motivation and aim of this work. Chapter 2 discusses several proof of principle and analytical concepts based on different graphene materials. These concepts point out the chemically deriv...

  12. Nanotechnological Basis for Advanced Sensors

    CERN Document Server

    Reithmaier, Johann Peter; Kulisch, Wilhelm; Popov, Cyril; Petkov, Plamen

    2011-01-01

    Bringing together experts from 15 countries, this book is based on the lectures and contributions of the NATO Advanced Study Institute on “Nanotechnological Basis for Advanced Sensors” held in Sozopol, Bulgaria, 30 May - 11 June, 2010. It gives a broad overview on this topic, and includes articles on: techniques for preparation and characterization of sensor materials; different types of nanoscaled materials for sensor applications, addressing both their structure (nanoparticles, nanocomposites, nanostructured films, etc.) and chemical nature (carbon-based, oxides, glasses, etc.); and on advanced sensors that exploit nanoscience and nanotechnology. In addition, the volume represents an interdisciplinary approach with authors coming from diverse fields such as physics, chemistry, engineering, materials science and biology. A particular strength of the book is its combination of longer papers, introducing the basic knowledge on a certain topic, and brief contributions highlighting special types of sensors a...

  13. Nanoparticle-based Sensors

    Directory of Open Access Journals (Sweden)

    V.K. Khanna

    2008-09-01

    Full Text Available Nanoparticles exhibit several unique properties that can be applied to develop chemical and biosensorspossessing desirable features like enhanced sensitivity and lower detection limits. Gold nanoparticles arecoated with sugars tailored to recognise different biological substances. When mixed with a weak solution ofthe sugar-coated nanoparticles, the target substance, e.g., ricin or E.coli, attaches to the sugar, thereby alteringits properties and changing the colour. Spores of bacterium labeled with carbon dots have been found to glowupon illumination when viewed with a confocal microscope. Enzyme/nanoparticle-based optical sensors forthe detection of organophosphate (OP compounds employ nanoparticle-modified fluorescence of an inhibitorof the enzyme to generate the signal for the OP compound detection. Nanoparticles shaped as nanoprisms,built of silver atoms, appear red on exposure to light. These nanoparticles are used as diagnostic labels thatglow when target DNA, e.g., those of anthrax or HIV, are present. Of great importance are tools like goldnanoparticle-enhanced surface-plasmon resonance sensor and silver nanoparticle surface-enhanced portableRaman integrated tunable sensor. Nanoparticle metal oxide chemiresistors using micro electro mechanical systemhotplate are very promising devices for toxic gas sensing. Chemiresistors comprising thin films of nanogoldparticles, encapsulated in monomolecular layers of functionalised alkanethiols, deposited on interdigitatedmicroelectrodes, show resistance changes through reversible absorption of vapours of harmful gases. Thispaper reviews the state-of-the-art sensors for chemical and biological terror agents, indicates their capabilitiesand applications, and presents the future scope of these devices.Defence Science Journal, 2008, 58(5, pp.608-616, DOI:http://dx.doi.org/10.14429/dsj.58.1683

  14. Chemical Sensing with Nanowires

    Science.gov (United States)

    Penner, Reginald M.

    2012-07-01

    Transformational advances in the performance of nanowire-based chemical sensors and biosensors have been achieved over the past two to three years. These advances have arisen from a better understanding of the mechanisms of transduction operating in these devices, innovations in nanowire fabrication, and improved methods for incorporating receptors into or onto nanowires. Nanowire-based biosensors have detected DNA in undiluted physiological saline. For silicon nanowire nucleic acid sensors, higher sensitivities have been obtained by eliminating the passivating oxide layer on the nanowire surface and by substituting uncharged protein nucleic acids for DNA as the capture strands. Biosensors for peptide and protein cancer markers, based on both semiconductor nanowires and nanowires of conductive polymers, have detected these targets at physiologically relevant concentrations in both blood plasma and whole blood. Nanowire chemical sensors have also detected several gases at the parts-per-million level. This review discusses these and other recent advances, concentrating on work published in the past three years.

  15. Medical preparation container comprising microwave powered sensor assembly

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention relates to a medical preparation container which comprises a microwave powered sensor assembly. The microwave powered sensor assembly comprises a sensor configured to measure a physical property or chemical property of a medical preparation during its heating in a microwave...

  16. Electronic Tongue Containing Redox and Conductivity Sensors

    Science.gov (United States)

    Buehler, Martin

    2007-01-01

    The Electronic Tongue (E-tongue 2) is an assembly of sensors for measuring concentrations of metal ions and possibly other contaminants in water. Potential uses for electronic tongues include monitoring the chemical quality of water in a variety of natural, industrial, and laboratory settings, and detecting micro-organisms indirectly by measuring microbially influenced corrosion. The device includes a heater, a temperature sensor, an oxidation/reduction (redox) sensor pair, an electrical sensor, an array of eight galvanic cells, and eight ion-specific electrodes.

  17. A highly selective fluorescent sensor for glucosamine.

    Science.gov (United States)

    Tran, Tam Minh; Alan, Yuksel; Glass, Timothy Edward

    2015-05-07

    A new fluorescent chemical sensor for glucosamine is reported. The sensor is based on a boronic acid-containing coumarin aldehyde and shows excellent selectivity for glucosamine by forming a boronic ester with the sugar diol as well as an iminium ion with the amine group of glucosamine. The sensor successfully discriminates glucosamine over other similar biomolecules in terms of both fluorescence intensity and binding affinity. This method provides a new concept for the design and synthesis of very selective turn-on optical sensors for selective detection of multi-functional biomolecules.

  18. Preparation and analysis of zirconia oxygen sensors

    Institute of Scientific and Technical Information of China (English)

    LUO Zhi-an; XIAO Jian-zhong; XIA Feng

    2006-01-01

    Thimble zirconia oxygen sensors were prepared with yttria stabilized zirconia(YSZ). The surfaces of the electrode,electrolyte and their interface were observed by scanning electron microscope(SEM). The sensor was examined with engine bench test to evaluate the essential performance. The results show that the oxygen sensor has good performance,which can meet the demand of practical applications. Chemical equilibrium theory was introduced to explain electromotive force of the sensors and the influence of temperature on the signals. The educed theoretical model of electromotive force agrees well with testing results.

  19. Microbar sensor

    Science.gov (United States)

    Wachter, Eric A.; Thundat, Thomas G.

    1995-01-01

    A mass microsensor is fabricated with a microcantilever oscillated by a piezoelectric transducer. A chemical coating having absorptive or adsorptive affinity for a specifically targeted chemical or compound is applied to the microcantilever for oscillation in the monitored atmosphere. Molecules of the targeted chemical attach to the microcantilever coating resulting in an oscillating mass increase which influences the resonant frequency of the microcantilever oscillation. The rate at which the coated microcantilever accumulates the target chemical is functional of the target chemical concentration. Consequently, the extent of microcantilever oscillation frequency change is related to the concentration of the target chemical within the monitored atmosphere. Such oscillation frequency changes are detected by a center-crossing photodiode which responds to a laser diode beam reflected from the microcantilever surface resulting in an output frequency from the photodiode that is synchronous with the microcantilever frequency.

  20. Gas sensor

    Science.gov (United States)

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

    2014-09-09

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

  1. Load sensor

    NARCIS (Netherlands)

    Van den Ende, D.; Almeida, P.M.R.; Dingemans, T.J.; Van der Zwaag, S.

    2007-01-01

    The invention relates to a load sensor comprising a polymer matrix and a piezo-ceramic material such as PZT, em not bedded in the polymer matrix, which together form a compos not ite, wherein the polymer matrix is a liquid crystalline resin, and wherein the piezo-ceramic material is a PZT powder for

  2. Biomimetic Receptors and Sensors

    Directory of Open Access Journals (Sweden)

    Franz L. Dickert

    2014-11-01

    Full Text Available In biomimetics, living systems are imitated to develop receptors for ions, molecules and bioparticles. The most pertinent idea is self-organization in analogy to evolution in nature, which created the key-lock principle. Today, modern science has been developing host-guest chemistry, a strategy of supramolecular chemistry for designing interactions of analytes with synthetic receptors. This can be realized, e.g., by self-assembled monolayers (SAMs or molecular imprinting. The strategies are used for solid phase extraction (SPE, but preferably in developing recognition layers of chemical sensors.

  3. Process monitoring using ultrasonic sensor systems.

    Science.gov (United States)

    Henning, Bernd; Rautenberg, Jens

    2006-12-22

    Continuous in-line measurement of substance concentration in liquid mixtures is valuable in improving industrial processes in terms of material properties, energy efficiency and process safety. Ultrasonic sensor systems meet the practical requirements of a chemical sensor quite well. Currently ultrasonic sensor systems are widely used as acoustic chemical sensors to measure concentration of selected substances or to monitor the course of polymerisation, crystallisation or fermentation processes. Useable acoustic properties for the characterisation of liquid mixtures are sound velocity, sound absorption and acoustic impedance. This contribution will give a short overview of the state of the art and several trends for the use of ultrasonic sensor systems in process applications. Novel investigations show the very promising possibility to analyse liquid multi-phase mixtures like suspensions, emulsions and dispersions.

  4. Emissive sensors and devices incorporating these sensors

    Science.gov (United States)

    Swager, Timothy M; Zhang, Shi-Wei

    2013-02-05

    The present invention generally relates to luminescent and/or optically absorbing compositions and/or precursors to those compositions, including solid films incorporating these compositions/precursors, exhibiting increased luminescent lifetimes, quantum yields, enhanced stabilities and/or amplified emissions. The present invention also relates to sensors and methods for sensing analytes through luminescent and/or optically absorbing properties of these compositions and/or precursors. Examples of analytes detectable by the invention include electrophiles, alkylating agents, thionyl halides, and phosphate ester groups including phosphoryl halides, cyanides and thioates such as those found in certain chemical warfare agents. The present invention additionally relates to devices and methods for amplifying emissions, such as those produced using the above-described compositions and/or precursors, by incorporating the composition and/or precursor within a polymer having an energy migration pathway. In some cases, the compositions and/or precursors thereof include a compound capable of undergoing a cyclization reaction.

  5. Biomimetic virus-based colourimetric sensors

    Science.gov (United States)

    Oh, Jin-Woo; Chung, Woo-Jae; Heo, Kwang; Jin, Hyo-Eon; Lee, Byung Yang; Wang, Eddie; Zueger, Chris; Wong, Winnie; Meyer, Joel; Kim, Chuntae; Lee, So-Young; Kim, Won-Geun; Zemla, Marcin; Auer, Manfred; Hexemer, Alexander; Lee, Seung-Wuk

    2014-01-01

    Many materials in nature change colours in response to stimuli, making them attractive for use as sensor platform. However, both natural materials and their synthetic analogues lack selectivity towards specific chemicals, and introducing such selectivity remains a challenge. Here we report the self-assembly of genetically engineered viruses (M13 phage) into target-specific, colourimetric biosensors. The sensors are composed of phage-bundle nanostructures and exhibit viewing-angle independent colour, similar to collagen structures in turkey skin. On exposure to various volatile organic chemicals, the structures rapidly swell and undergo distinct colour changes. Furthermore, sensors composed of phage displaying trinitrotoluene (TNT)-binding peptide motifs identified from a phage display selectively distinguish TNT down to 300 p.p.b. over similarly structured chemicals. Our tunable, colourimetric sensors can be useful for the detection of a variety of harmful toxicants and pathogens to protect human health and national security.

  6. NANOSCALE SCIENCE AND TECHNOLOGY FOR THE DEVELOPMENT OF ENVIRONMENTAL SENSORS

    Energy Technology Data Exchange (ETDEWEB)

    Ronald Andres, School of Chemical Engineering, Purdue University

    2007-01-03

    Under this funding, we proposed to: i) develop a ChemFET sensor platform, ii) develop a ChemDiode sensor platform, iii) synthesize receptor molecules suitable for chemical sensing, iv) study the electrostatic potential changes induced by receptor/target binding on surfaces and v) develop VLSI fabrication approaches for micron-scale chemical sensor devices. The accomplishments under these various thrusts are summarized in this section.

  7. Application of Ionic Liquids in Amperometric Gas Sensors.

    Science.gov (United States)

    Gębicki, Jacek; Kloskowski, Adam; Chrzanowski, Wojciech; Stepnowski, Piotr; Namiesnik, Jacek

    2016-01-01

    This article presents an analysis of available literature data on metrological parameters of the amperometric gas sensors containing ionic liquids as an electrolyte. Four mechanism types of signal generation in amperometric sensors with ionic liquid are described. Moreover, this article describes the influence of selected physico-chemical properties of the ionic liquids on the metrological parameters of these sensors. Some metrological parameters are also compared for amperometric sensors with GDE and SPE electrodes and with ionic liquids for selected analytes.

  8. Mission-Adaptable Chemical Sensor (MACS)

    Science.gov (United States)

    2009-03-27

    CKD GFVB55 & CKD GFVB25)......................................................... 129 Heaters...chassis, a required sensitivity of better than 100 PPT, and an 18 month development cycle. These somewhat mutually exclusive requirements caused the team...transfer valve is opened. Heat is applied to the sorbent to cause trapped analytes to be released into the sample cell. 5. Pressure in the sample

  9. Piezoelectric cantilever sensors

    Science.gov (United States)

    Shih, Wan Y. (Inventor); Shih, Wei-Heng (Inventor); Shen, Zuyan (Inventor)

    2008-01-01

    A piezoelectric cantilever with a non-piezoelectric, or piezoelectric tip useful as mass and viscosity sensors. The change in the cantilever mass can be accurately quantified by monitoring a resonance frequency shift of the cantilever. For bio-detection, antibodies or other specific receptors of target antigens may be immobilized on the cantilever surface, preferably on the non-piezoelectric tip. For chemical detection, high surface-area selective absorbent materials are coated on the cantilever tip. Binding of the target antigens or analytes to the cantilever surface increases the cantilever mass. Detection of target antigens or analytes is achieved by monitoring the cantilever's resonance frequency and determining the resonance frequency shift that is due to the mass of the adsorbed target antigens on the cantilever surface. The use of a piezoelectric unimorph cantilever allows both electrical actuation and electrical sensing. Incorporating a non-piezoelectric tip (14) enhances the sensitivity of the sensor. In addition, the piezoelectric cantilever can withstand damping in highly viscous liquids and can be used as a viscosity sensor in wide viscosity range.

  10. Semiconductor sensors

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, Frank, E-mail: frank.hartmann@cern.c [Institut fuer Experimentelle Kernphysik, KIT, Wolfgang-Gaede-Str. 1, Karlsruhe 76131 (Germany)

    2011-02-01

    Semiconductor sensors have been around since the 1950s and today, every high energy physics experiment has one in its repertoire. In Lepton as well as Hadron colliders, silicon vertex and tracking detectors led to the most amazing physics and will continue doing so in the future. This contribution tries to depict the history of these devices exemplarily without being able to honor all important developments and installations. The current understanding of radiation damage mechanisms and recent R and D topics demonstrating the future challenges and possible technical solutions for the SLHC detectors are presented. Consequently semiconductor sensor candidates for an LHC upgrade and a future linear collider are also briefly introduced. The work presented here is a collage of the work of many individual silicon experts spread over several collaborations across the world.

  11. Corrosion sensor

    Science.gov (United States)

    Glass, Robert S.; Clarke, Jr., Willis L.; Ciarlo, Dino R.

    1994-01-01

    A corrosion sensor array incorporating individual elements for measuring various elements and ions, such as chloride, sulfide, copper, hydrogen (pH), etc. and elements for evaluating the instantaneous corrosion properties of structural materials. The exact combination and number of elements measured or monitored would depend upon the environmental conditions and materials used which are subject to corrosive effects. Such a corrosion monitoring system embedded in or mounted on a structure exposed to the environment would serve as an early warning system for the onset of severe corrosion problems for the structure, thus providing a safety factor as well as economic factors. The sensor array is accessed to an electronics/computational system, which provides a means for data collection and analysis.

  12. Handbook of modern sensors physics, designs, and applications

    CERN Document Server

    Fraden, Jacob

    2016-01-01

    This book presents a comprehensive and up-to-date account of the theory (physical principles), design, and practical implementations of various sensors for scientific, industrial, and consumer applications. This latest edition focuses on the sensing technologies driven by the expanding use of sensors in mobile devices. These new miniature sensors will be described, with an emphasis on smart sensors which have embedded processing systems. The chapter on chemical sensors has also been expanded to present the latest developments. Digital systems, however complex and intelligent they may be, must receive information from the outside world that is generally analog and not electrical. Sensors are interface devices between various physical values and the electronic circuits that "understand" only a language of moving electrical charges. In other words, sensors are the eyes, ears, and noses of silicon chips. Unlike other books on sensors, the Handbook of Modern Sensors is organized according to the measured variables...

  13. Thermal flow micro sensors

    OpenAIRE

    Elwenspoek, M.

    1999-01-01

    A review is given on sensors fabricated by silicon micromachining technology using the thermal domain for the measurement of fluid flow. Attention is paid especially to performance and geometry of the sensors. Three basic types of thermal flow sensors are discussed: anemometers, calorimetric flow sensors and time of flight flow sensors. Anemometers may comprise several heaters and temperature sensors and from a geometric point of view are similar sometimes for calorimetric flow sensors. We fi...

  14. Aircraft Cabin Environmental Quality Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Gundel, Lara; Kirchstetter, Thomas; Spears, Michael; Sullivan, Douglas

    2010-05-06

    The Indoor Environment Department at Lawrence Berkeley National Laboratory (LBNL) teamed with seven universities to participate in a Federal Aviation Administration (FAA) Center of Excellence (COE) for research on environmental quality in aircraft. This report describes research performed at LBNL on selecting and evaluating sensors for monitoring environmental quality in aircraft cabins, as part of Project 7 of the FAA's COE for Airliner Cabin Environmental Research (ACER)1 effort. This part of Project 7 links to the ozone, pesticide, and incident projects for data collection and monitoring and is a component of a broader research effort on sensors by ACER. Results from UCB and LBNL's concurrent research on ozone (ACER Project 1) are found in Weschler et al., 2007; Bhangar et al. 2008; Coleman et al., 2008 and Strom-Tejsen et al., 2008. LBNL's research on pesticides (ACER Project 2) in airliner cabins is described in Maddalena and McKone (2008). This report focused on the sensors needed for normal contaminants and conditions in aircraft. The results are intended to complement and coordinate with results from other ACER members who concentrated primarily on (a) sensors for chemical and biological pollutants that might be released intentionally in aircraft; (b) integration of sensor systems; and (c) optimal location of sensors within aircraft. The parameters and sensors were selected primarily to satisfy routine monitoring needs for contaminants and conditions that commonly occur in aircraft. However, such sensor systems can also be incorporated into research programs on environmental quality in aircraft cabins.

  15. Optical Fiber Grating based Sensors

    DEFF Research Database (Denmark)

    Michelsen, Susanne

    2003-01-01

    In this thesis differenct optical fiber gratings are used for sensor purposes. If a fiber with a core concentricity error (CCE) is used, a directional dependent bend sensor can be produced. The CCE direction can be determined by means of diffraction. This makes it possible to produce long......-period gratings in a fiber with a CCE direction parallel or perpendicular to the writing direction. The maximal bending sensitivity is independent on the writing direction, but the detailed bending response is different in the two cases. A temperature and strain sensor, based on a long-period grating and two...... wavelength. It is shown that it is possible to tune and modulate a DFB fiber laser with both strain from a piezoelectric transducer and by temperature through resistive heating of a methal film. Both a chemical deposited silver layer and an electron-beam evaporation technique has been investigated, to find...

  16. Hydrogen sensor

    Science.gov (United States)

    Duan, Yixiang; Jia, Quanxi; Cao, Wenqing

    2010-11-23

    A hydrogen sensor for detecting/quantitating hydrogen and hydrogen isotopes includes a sampling line and a microplasma generator that excites hydrogen from a gas sample and produces light emission from excited hydrogen. A power supply provides power to the microplasma generator, and a spectrometer generates an emission spectrum from the light emission. A programmable computer is adapted for determining whether or not the gas sample includes hydrogen, and for quantitating the amount of hydrogen and/or hydrogen isotopes are present in the gas sample.

  17. Sensor-Web Operations Explorer

    Science.gov (United States)

    Meemong, Lee; Miller, Charles; Bowman, Kevin; Weidner, Richard

    2008-01-01

    Understanding the atmospheric state and its impact on air quality requires observations of trace gases, aerosols, clouds, and physical parameters across temporal and spatial scales that range from minutes to days and from meters to more than 10,000 kilometers. Observations include continuous local monitoring for particle formation; field campaigns for emissions, local transport, and chemistry; and periodic global measurements for continental transport and chemistry. Understanding includes global data assimilation framework capable of hierarchical coupling, dynamic integration of chemical data and atmospheric models, and feedback loops between models and observations. The objective of the sensor-web system is to observe trace gases, aerosols, clouds, and physical parameters, an integrated observation infrastructure composed of space-borne, air-borne, and in-situ sensors will be simulated based on their measurement physics properties. The objective of the sensor-web operation is to optimally plan for heterogeneous multiple sensors, the sampling strategies will be explored and science impact will be analyzed based on comprehensive modeling of atmospheric phenomena including convection, transport, and chemical process. Topics include system architecture, software architecture, hardware architecture, process flow, technology infusion, challenges, and future direction.

  18. Chemical Emergencies

    Science.gov (United States)

    When a hazardous chemical has been released, it may harm people's health. Chemical releases can be unintentional, as in the case of an ... the case of a terrorist attack with a chemical weapon. Some hazardous chemicals have been developed by ...

  19. DNA and RNA sensor

    Institute of Scientific and Technical Information of China (English)

    LIU; Tao; LIN; Lin; ZHAO; Hong; JIANG; Long

    2005-01-01

    This review summarizes recent advances in DNA sensor. Major areas of DNA sensor covered in this review include immobilization methods of DNA, general techniques of DNA detection and application of nanoparticles in DNA sensor.

  20. Sensors for Entertainment.

    Science.gov (United States)

    Lamberti, Fabrizio; Sanna, Andrea; Rokne, Jon

    2016-07-15

    Sensors are becoming ubiquitous in all areas of science, technology, and society. In this Special Issue on "Sensors for Entertainment", developments in progress and the current state of application scenarios for sensors in the field of entertainment is explored.

  1. Resistive flex sensors: a survey

    Science.gov (United States)

    Saggio, Giovanni; Riillo, Francesco; Sbernini, Laura; Quitadamo, Lucia Rita

    2016-01-01

    Resistive flex sensors can be used to measure bending or flexing with relatively little effort and a relatively low budget. Their lightness, compactness, robustness, measurement effectiveness and low power consumption make these sensors useful for manifold applications in diverse fields. Here, we provide a comprehensive survey of resistive flex sensors, taking into account their working principles, manufacturing aspects, electrical characteristics and equivalent models, useful front-end conditioning circuitry, and physic-bio-chemical aspects. Particular effort is devoted to reporting on and analyzing several applications of resistive flex sensors, related to the measurement of body position and motion, and to the implementation of artificial devices. In relation to the human body, we consider the utilization of resistive flex sensors for the measurement of physical activity and for the development of interaction/interface devices driven by human gestures. Concerning artificial devices, we deal with applications related to the automotive field, robots, orthosis and prosthesis, musical instruments and measuring tools. The presented literature is collected from different sources, including bibliographic databases, company press releases, patents, master’s theses and PhD theses.

  2. High-Temperature Optical Sensor

    Science.gov (United States)

    Adamovsky, Grigory; Juergens, Jeffrey R.; Varga, Donald J.; Floyd, Bertram M.

    2010-01-01

    A high-temperature optical sensor (see Figure 1) has been developed that can operate at temperatures up to 1,000 C. The sensor development process consists of two parts: packaging of a fiber Bragg grating into a housing that allows a more sturdy thermally stable device, and a technological process to which the device is subjected to in order to meet environmental requirements of several hundred C. This technology uses a newly discovered phenomenon of the formation of thermally stable secondary Bragg gratings in communication-grade fibers at high temperatures to construct robust, optical, high-temperature sensors. Testing and performance evaluation (see Figure 2) of packaged sensors demonstrated operability of the devices at 1,000 C for several hundred hours, and during numerous thermal cycling from 400 to 800 C with different heating rates. The technology significantly extends applicability of optical sensors to high-temperature environments including ground testing of engines, flight propulsion control, thermal protection monitoring of launch vehicles, etc. It may also find applications in such non-aerospace arenas as monitoring of nuclear reactors, furnaces, chemical processes, and other hightemperature environments where other measurement techniques are either unreliable, dangerous, undesirable, or unavailable.

  3. Battery-free Wireless Sensor Network For Advanced Fossil-Fuel Based Power Generation

    Energy Technology Data Exchange (ETDEWEB)

    Yi Jia

    2011-02-28

    This report summarizes technical progress achieved during the project supported by the Department of Energy under Award Number DE-FG26-07NT4306. The aim of the project was to conduct basic research into battery-free wireless sensing mechanism in order to develop novel wireless sensors and sensor network for physical and chemical parameter monitoring in a harsh environment. Passive wireless sensing platform and five wireless sensors including temperature sensor, pressure sensor, humidity sensor, crack sensor and networked sensors developed and demonstrated in our laboratory setup have achieved the objective for the monitoring of various physical and chemical parameters in a harsh environment through remote power and wireless sensor communication, which is critical to intelligent control of advanced power generation system. This report is organized by the sensors developed as detailed in each progress report.

  4. A bionics chemical synapse.

    Science.gov (United States)

    Thanapitak, Surachoke; Toumazou, Christofer

    2013-06-01

    Implementation of the current mode CMOS circuit for chemical synapses (AMPA and NMDA receptors) with dynamic change of glutamate as the neurotransmitter input is presented in this paper. Additionally, circuit realisation for receptor GABA(A) and GABA(B) with an electrical signal which symbolises γ-Aminobutyric Acid (GABA) perturbation is introduced. The chemical sensor for glutamate sensing is the modified ISFET with enzyme (glutamate oxidase) immobilisation. The measured results from these biomimetics chemical synapse circuits closely match with the simulation result from the mathematical model. The total power consumption of the whole chip (four chemical synapse circuits and all auxiliary circuits) is 168.3 μW. The total chip area is 3 mm(2) in 0.35-μm AMS CMOS technology.

  5. Fiber optic liquid refractive index sensor

    Science.gov (United States)

    Bhardwaj, Vanita; Gangwar, Rahul Kumar; Singh, Vinod Kumar

    2015-08-01

    In this present work we report fabrication of fiber optic liquid refractive index (RI) measurement sensor based on Michelson Interferometer method. This sensor was assembled by using graded index multimode (MM) fiber with core diameter 50 µm and the cladding of fiber was removed by simple chemical method. To perform this experiment a 2×2 3dB coupler is used. The fiber ends are then immersed in solvent and solution to provide reference and refractive index measurements, respectively. This method was successfully used to measure refractive index of Sodium Chloride (NaCl)-Water solution at different concentrations. The fringe contrast sensitivity of device is 92.90 dB/RIU measured in the RI range from 1.34 to 1.42 which is better than Mach-Zehnder Interferometer sensor [1] and Fabry perot based sensor [2]. The fabrication of sensor is simple, low cost and highly sensitive.

  6. Challenges in the development of sensors for monitoring automobile emissions

    Energy Technology Data Exchange (ETDEWEB)

    Glass, R.S.; Pham, A.Q.

    1997-02-20

    A new generation of on-board automotive sensors are needed for diagnosis and control of engines and catalytic converters. With regard to catalytic converters, the intent of these regulations is to ensure that the vehicle operator is informed when emission control system are no longer performing adequately. In order to be commercialized, sensors for emission control must meet certain criteria, including low cost, reliability, and manufacturability. We have been developing solid state electrochemical sensors for emission control. Most recently, our work has focused on the development of hydrocarbon sensors for monitoring catalytic converter performance. Previous work was concerned with the development of an oxygen sensor having appropriate sensitivity for lean-burn engines. Operational limits for oxygen sensors have been defined and new materials have been developed for hydrocarbon sensors. Technical results are presented here as well as challenges to be met in the development of materials and designs for new chemical sensors for monitoring automotive emissions.

  7. EDITORIAL: Humidity sensors Humidity sensors

    Science.gov (United States)

    Regtien, Paul P. L.

    2012-01-01

    produced at relatively low cost. Therefore, they find wide use in lots of applications. However, the method requires a material that possesses some conflicting properties: stable and reproducible relations between air humidity, moisture uptake and a specific property (for instance the length of a hair, the electrical impedance of the material), fast absorption and desorption of the water vapour (to obtain a short response time), small hysteresis, wide range of relative humidity (RH) and temperature-independent output (only responsive to RH). For these reasons, much research is done and is still going on to find suitable materials that combine high performance and low price. In this special feature, three of the four papers report on absorption sensors, all with different focus. Aziz et al describe experiments with newly developed materials. The surface structure is extensively studied, in view of its ability to rapidly absorb water vapour and exhibit a reproducible change in the resistance and capacitance of the device. Sanchez et al employ optical fibres coated with a thin moisture-absorbing layer as a sensitive humidity sensor. They have studied various coating materials and investigated the possibility of using changes in optical properties of the fibre (here the lossy mode resonance) due to a change in humidity of the surrounding air. The third paper, by Weremczuk et al, focuses on a cheap fabrication method for absorption-based humidity sensors. The inkjet technology appears to be suitable for mass fabrication of such sensors, which is demonstrated by extensive measurements of the electrical properties (resistance and capacitance) of the absorbing layers. Moreover, they have developed a model that describes the relation between humidity and the electrical parameters of the moisture-sensitive layer. Despite intensive research, absorption sensors still do not meet the requirements for high accuracy applications. The dew-point temperature method is more appropriate

  8. Odor identification sensor system; Nioi shikibetsu sensa shisutemu

    Energy Technology Data Exchange (ETDEWEB)

    Takada, Tadashi.; Suzuki, Kendo

    1999-09-01

    The development of the device human five senses substitution is being asked. In this, though the nose of the living body is imitated and it proceeds with the development, as for a sense, it is still far beyond the performance of the human nose to smell bad by the various chemical sensors and the information processing technology. It smells by using the metal oxide semiconductor ceremony sensor it has the sex that various smells is chosen, and we develop a sensor, and proceed with the realization of the questionable distinction sensor system, which used these sensors. (NEDO)

  9. Gas Sensors Based on Electrodeposited Polymers

    Directory of Open Access Journals (Sweden)

    Boris Lakard

    2015-07-01

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

  10. Nanoscale Electrocatlyst for Chemicalnd Biolgical Sensor

    DEFF Research Database (Denmark)

    Zhu, Nan

    interests in understanding of fundamental electronic properties of hybrid nanomaterials and their potential applications in next generation ultra-sensitive chemical sensors and biosensors. As the first man-made coordination compound, Prussian Blue (PB) has a long history dating back over 300 years ago (the...... first synthesis in 1704). This interesting material has recently been used broadly as an electron transfer (ET) catalyst for new chemical and biological sensors. We have initiated efforts in synthesis, functional characterization and applications of PB in novel nanostructured forms focused on controlled......-standing graphene papers. PBNPs doped graphene paper shows highly efficient electrocatalysis towards reduction of hydrogen peroxide and can be used as flexible chemical sensors for potential applications in detection of hydrogen peroxide or/and other organic peroxides. The as-prepared PBNPs-RGO paper is further...

  11. Long Wave Infrared Cavity Enhanced Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Taubman, Matthew S.; Scott, David C.; Cannon, Bret D.; Myers, Tanya L.; Munley, John T.; Nguyen, Vinh T.; Schultz, John F.

    2005-12-01

    The principal goal of Pacific Northwest National Laboratory's (PNNL's) long wave infrared (LWIR) cavity enhanced sensor (CES) task is to explore ultra-sensitive spectroscopic chemical sensing techniques and apply them to detecting proliferation of weapons of mass destruction (WMD). Our primary application is detecting signatures of WMD production, but LWIR CES techniques are also capable of detecting chemical weapons. The LWIR CES task is concerned exclusively with developing novel point sensors; stand-off detection is addressed by other PNNL tasks and projects. PNNL's LWIR CES research is distinguished from that done by others by the use quantum cascade lasers (QCLs) as the light source. QCLs are novel devices, and a significant fraction of our research has been devoted to developing the procedures and hardware required to implement them most effectively for chemical sensing. This report details the progress we have made on LWIR CES sensor development.

  12. Trends in Robotic Sensor Technologies for Fruit Harvesting: 2010-2015

    DEFF Research Database (Denmark)

    Zujevs, Andrejs; Osadcuks, Vitalijs; Ahrendt, Peter

    2015-01-01

    complex. Precision Agriculture provides the possibility to use soil more intelligently and effectively. Precision Agriculture includes sensor technologies for yield mapping and measuring, soil sensing, nutrient and pesticide application, irrigation control, robotic harvesting, etc. With the increase...... classified in the following categories: computer vision, chemical sensors, tactile sensors and proximity sensors. The main trends in the future of robotic harvesting will involve usage of combinations of different sensor systems that provide accuracy and reliability....

  13. Detection of Electrophilic and Nucleophilic Chemical Agents

    Energy Technology Data Exchange (ETDEWEB)

    McElhanon, James R. (Manteca, CA); Shepodd, Timothy J. (Livermore, CA)

    2008-11-11

    A "real time" method for detecting electrophilic and nucleophilic species generally by employing tunable, precursor sensor materials that mimic the physiological interaction of these agents to form highly florescent berberine-type alkaloids that can be easily and rapidly detected. These novel precursor sensor materials can be tuned for reaction with both electrophilic (chemical species, toxins) and nucleophilic (proteins and other biological molecules) species.

  14. Woven electrochemical fabric-based test sensors (WEFTS): a new class of multiplexed electrochemical sensors.

    Science.gov (United States)

    Choudhary, Tripurari; Rajamanickam, G P; Dendukuri, Dhananjaya

    2015-05-07

    We present textile weaving as a new technique for the manufacture of miniature electrochemical sensors with significant advantages over current fabrication techniques. Biocompatible silk yarn is used as the material for fabrication instead of plastics and ceramics used in commercial sensors. Silk yarns are coated with conducting inks and reagents before being handloom-woven as electrodes into patches of fabric to create arrays of sensors, which are then laminated, cut and packaged into individual sensors. Unlike the conventionally used screen-printing, which results in wastage of reagents, yarn coating uses only as much reagent and ink as required. Hydrophilic and hydrophobic yarns are used for patterning so that sample flow is restricted to a small area of the sensor. This simple fluidic control is achieved with readily available materials. We have fabricated and validated individual sensors for glucose and hemoglobin and a multiplexed sensor, which can detect both analytes. Chronoamperometry and differential pulse voltammetry (DPV) were used to detect glucose and hemoglobin, respectively. Industrial quantities of these sensors can be fabricated at distributed locations in the developing world using existing skills and manufacturing facilities. We believe such sensors could find applications in the emerging area of wearable sensors for chemical testing.

  15. Mictrostructured sensor systems for chemical gas analysis - 'MISCHGAS'. Vol. 1: Reports 1 - 6. Final report; Mikrostrukturierte Sensorsysteme fuer die chemische Gasanalyse - 'MISCHGAS'. Bd. 1: Teilberichte 1 - 6. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-07-01

    The project MISCHGAS was aimed at low-power microstructured multisensor systems for analyses of complex gas mixtures. This comprised 1. the development of the sensor chip (sensor layout, sandwich sensor systems, ultrathin carrier materials, and sol-gel technologies), 2. investigation of atomistic and electrical sensor mechanism, 3. design and construction (glues, materials, noble metal free contact systems), 4. generation and reading of the sensor signal, 5. investigation of the analytical properties of the sensors, 6. user-oriented specialised gas analysis systems. [German] Ziel des Projektes MISCHGAS sind leistungsarme, mikrostrukturierte, multisensor-geeignete Systeme fuer die Analyse sowohl einzelner als auch mehrerer Kompoenten komplexer Gasgemische. Dazu wurden die notwendigen Teilbereiche: technologische Entwicklungen des Sensorchips, Klaerung atomistischer sowie elektrischer Sensormechanismen, Aufbau und Verbindungstechnik, Generierung und Auslesung des Sensorsignals, Ermittlung der analytischen Eigenschaften der Sensoren, anwenderorientierte spezialisierte Gasmesssysteme von den Verbundpartnern bearbeitet. Hauptpunkte neuer technologischer Entwicklungen waren Sensorlayout, Sensorschichtsysteme sowie ultraduenne Traegermaterialien ueber die 'porous silicon sacrificial layer'-Technik sowie Sol-Gel-Technologien. Damit konnten leistungsarme Traeger hergestellt werden. Materialien waren SnO{sub 2} und V{sub 2}O{sub 5}. Der Einfluss von Pt auf die Sensorreaktion konnte beschrieben werden. Das Verstaendnis phaenomenologischer Zusammenhaenge von Sensormechanismen und deren physikalisch-chemisch-analytischer Erfassung sowie der festkoerperphysikalischen Beschreibung wurde deutlich verbessert. Technologie und Prozesstechnik wurden auf Gesichtspunkte wie Qualitaetssicherung, und Transferierbarkeit ausgerichtet. Weitere Arbeitsbereiche sind die Gehaeuseentwicklung und Fixierung im Gehaeuse. In der AVT gab es Fortschritte bei Kleber und Aufbauhilfsstoffen

  16. High-Temperature Gas Sensor Array (Electronic Nose) Demonstrated

    Science.gov (United States)

    Hunter, Gary W.

    2002-01-01

    The ability to measure emissions from aeronautic engines and in commercial applications such as automotive emission control and chemical process monitoring is a necessary first step if one is going to actively control those emissions. One single sensor will not give all the information necessary to determine the chemical composition of a high-temperature, harsh environment. Rather, an array of gas sensor arrays--in effect, a high-temperature electronic "nose"--is necessary to characterize the chemical constituents of a diverse, high-temperature environment, such as an emissions stream. The signals produced by this nose could be analyzed to determine the constituents of the emission stream. Although commercial electronic noses for near-room temperature applications exist, they often depend significantly on lower temperature materials or only one sensor type. A separate development effort necessary for a high-temperature electronic nose is being undertaken by the NASA Glenn Research Center, Case Western Reserve University, Ohio State University, and Makel Engineering, Inc. The sensors are specially designed for hightemperature environments. A first-generation high-temperature electronic nose has been demonstrated on a modified automotive engine. This nose sensor array was composed of sensors designed for hightemperature environments fabricated using microelectromechanical-systems- (MEMS-) based technology. The array included a tin-oxide-based sensor doped for nitrogen oxide (NOx) sensitivity, a SiC-based hydrocarbon (CxHy) sensor, and an oxygen sensor (O2). These sensors operate on different principles--resistor, diode, and electrochemical cell, respectively--and each sensor has very different responses to the individual gases in the environment. A picture showing the sensor head for the array is shown in the photograph on the left and the sensors installed in the engine are shown in the photograph on the right. Electronics are interfaced with the sensors for

  17. Integrated Optical Sensors

    NARCIS (Netherlands)

    Lambeck, Paul V.; Hoekstra, Hugo

    2003-01-01

    The optical (tele-) communication is the main driving force for the worldwide R&D on integrated optical devices and microsystems. lO-sensors have to compete with many other sensor types both within the optical domain (fiber sensors) and outside that domain, where sensors based on measurand induced c

  18. Wireless ferroelectric resonating sensor.

    Science.gov (United States)

    Viikari, Ville; Seppa, Heikki; Mattila, Tomi; Alastalo, Ari

    2010-04-01

    This paper presents a passive wireless resonating sensor that is based on a ferroelectric varactor. The sensor replies with its data at an intermodulation frequency when a reader device illuminates it at 2 closely located frequencies. The paper derives a theoretical equation for the response of such a sensor, verifies the theory by simulations, and demonstrates a temperature sensor based on a ferroelectric varactor.

  19. Sensor sentinel computing device

    Science.gov (United States)

    Damico, Joseph P.

    2016-08-02

    Technologies pertaining to authenticating data output by sensors in an industrial environment are described herein. A sensor sentinel computing device receives time-series data from a sensor by way of a wireline connection. The sensor sentinel computing device generates a validation signal that is a function of the time-series signal. The sensor sentinel computing device then transmits the validation signal to a programmable logic controller in the industrial environment.

  20. Advances in fiber optic sensors for in-vivo monitoring

    Science.gov (United States)

    Baldini, Francesco; Mignani, Anna G.

    1995-09-01

    Biomedical fiber-optic sensors are attractive for the measurement of both physical and chemical parameters as well as for spectral measurements directly performed on the patient. An overview of fiber-optic sensors for in vivo monitoring is given, with particular attention to the advantages that these sensors are able to offer in different fields of application such as cardiovascular and intensive care, angiology, gastroenterology, ophthalmology, oncology, neurology, dermatology, and dentistry.

  1. Sol-gel process preparation and evaluation of the analytical performances of an hydrazine specific chemical sensor; Preparation par procede sol-gel et evaluation des performances analytiques d`un capteur chimique specifique de l`hydrazine

    Energy Technology Data Exchange (ETDEWEB)

    Gojon, C

    1996-12-01

    The realisation of optical fibers active chemical collector to analyze hydrazine in line, in the spent fuel reprocessing process is the subject of this work. The p.dimethyl-amino-benzaldehyde has been chosen as reagent for its chemical and optical properties. 186 refs.

  2. Porous glasses for optical sensors

    Science.gov (United States)

    Dorosz, Dominik; Procyk, Bernadeta

    2006-03-01

    Microporous glasses from the Na II0-B II0 3-Si0 II system can be obtained by appropriate thermal and chemical treatment. During the thermal treatment the separation of the borate phase from the silicon skeleton has been occurred. The borates are in the form small drops joined to each other. In the course of chemical treatment the borates become leached in water, water solutions of acids or basis and the glass becomes porous. Microporous glasses may find application in many branches of science and engineering. The applications depend on the internal arrangement, size and shape of pores. These parameters may be in a wide range modified by a change of the chemical composition. The received porous glass was used as an element in optical fibre NO II sensor. The specific coloration reaction between organic reagents and NO II in the pores was occurred. It is possible to detection of 10-50 ppm NO II level.

  3. Haussdorff and hellinger for colorimetric sensor array classification

    DEFF Research Database (Denmark)

    Alstrøm, Tommy Sonne; Jensen, Bjørn Sand; Schmidt, Mikkel Nørgaard;

    2012-01-01

    Development of sensors and systems for detection of chemical compounds is an important challenge with applications in areas such as anti-terrorism, demining, and environmental monitoring. A newly developed colorimetric sensor array is able to detect explosives and volatile organic compounds...

  4. Solvatochromic sensor array for the identification of common organic solvents.

    Science.gov (United States)

    Rankin, Jacqueline M; Zhang, Qifan; LaGasse, Maria K; Zhang, Yinan; Askim, Jon R; Suslick, Kenneth S

    2015-04-21

    A cross-reactive colorimetric sensor array composed of solvatochromic dyes in semi-liquid matrices was used to successfully discriminate among eleven common solvents. The multidimensional array response is attributed to both chemical (i.e., analyte-dye interactions) and physical (i.e., spot blooming and refractive index alteration) changes in the sensor spot.

  5. Managed traffic evacuation using distributed sensor processing

    Science.gov (United States)

    Ramuhalli, Pradeep; Biswas, Subir

    2005-05-01

    This paper presents an integrated sensor network and distributed event processing architecture for managed in-building traffic evacuation during natural and human-caused disasters, including earthquakes, fire and biological/chemical terrorist attacks. The proposed wireless sensor network protocols and distributed event processing mechanisms offer a new distributed paradigm for improving reliability in building evacuation and disaster management. The networking component of the system is constructed using distributed wireless sensors for measuring environmental parameters such as temperature, humidity, and detecting unusual events such as smoke, structural failures, vibration, biological/chemical or nuclear agents. Distributed event processing algorithms will be executed by these sensor nodes to detect the propagation pattern of the disaster and to measure the concentration and activity of human traffic in different parts of the building. Based on this information, dynamic evacuation decisions are taken for maximizing the evacuation speed and minimizing unwanted incidents such as human exposure to harmful agents and stampedes near exits. A set of audio-visual indicators and actuators are used for aiding the automated evacuation process. In this paper we develop integrated protocols, algorithms and their simulation models for the proposed sensor networking and the distributed event processing framework. Also, efficient harnessing of the individually low, but collectively massive, processing abilities of the sensor nodes is a powerful concept behind our proposed distributed event processing algorithms. Results obtained through simulation in this paper are used for a detailed characterization of the proposed evacuation management system and its associated algorithmic components.

  6. Sensors an introductory course

    CERN Document Server

    Kalantar-zadeh, Kourosh

    2013-01-01

    Sensors: An Introductory Course provides an essential reference on the fundamentals of sensors. The book is designed to help readers in developing skills and the understanding required in order to implement a wide range of sensors that are commonly used in our daily lives. This book covers the basic concepts in the sensors field, including definitions and terminologies. The physical sensing effects are described, and devices which utilize these effects are presented. The most frequently used organic and inorganic sensors are introduced and the techniques for implementing them are discussed. This book: Provides a comprehensive representation of the most common sensors and can be used as a reference in relevant fields Presents learning materials in a concise and easy to understand manner Includes examples of how sensors are incorporated in real life measurements Contains detailed figures and schematics to assist in understanding the sensor performance Sensors: An Introductory Course is ideal for university stu...

  7. Smart Sensor Systems

    Science.gov (United States)

    Hunter, G. W.; Stetter, J. R.; Hesketh, P. J.; Liu, C. C.

    Sensors and sensor systems are vital to our awareness of our surroundings and provide safety, security, and surveillance, as well as enable monitoring of our health and environment. A transformative advance in the field of sensor technology has been the development of "Smart Sensor Systems". The definition of a Smart Sensor may vary, but typically at a minimum a Smart Sensor is the combination of a sensing element with processing capabilities provided by a microprocessor. That is, Smart Sensors are basic sensing elements with embedded intelligence. The sensor signal is fed to the microprocessor, which processes the data and provides an informative output to an external user. A more expansive view of a Smart Sensor System, which is used in this article, is illustrated in Fig. 19.1: a complete self-contained sensor system that includes the capabilities for logging, processing with a model of sensor response and other data, self-contained power, and an ability to transmit or display informative data to an outside user. The fundamental idea of a smart sensor is that the integration of silicon microprocessors with sensor technology cannot only provide interpretive power and customized outputs, but also significantly improve sensor system performance and capabilities.

  8. GLIMPS sensor and taggant delivery systems

    Science.gov (United States)

    Nunan, Scott C.; Coakley, Peter G.; Niederhaus, Gregory A.; Lum, Chris

    2001-02-01

    A system has been developed for delivering and attaching a sensor payload to a target using a standard 40-mm grenade launcher. The GLIMPS projectile is intended to be a general purpose delivery system for a variety of sensor payloads including visual, acoustic, and chemical sensors. The GLIMPS projectile flight characteristics are similar to existing 40-mm rounds, with a useful range of up to 300 m. The projectile incorporates an attachment mechanism, a shock mitigation system, a power source, and a telemetry system for transmission of sensor data at up to 1/4 mile range. A second design is also being considered. It is a small taggant projectile that uses an adhesive to attach a tracking transmitter or other small payload to a vehicle at up to 50 m range. While initially developed as a military system, both projectiles can be used to enhance law enforcement operations.

  9. Advanced Sensors for Safety and Security

    CERN Document Server

    Khudaverdyan, Surik

    2013-01-01

    This book results from a NATO Advanced Research Workshop titled “Technological Innovations in CBRNE Sensing and Detection for Safety, Security, and Sustainability” held in Yerevan, Armenia in 2012. The objective was to discuss and exchange views as to how fusion of advanced technologies can lead to improved sensors/detectors in support of defense, security, and situational awareness. The chapters range from policy and implementation, advanced sensor platforms using stand-off (THz and optical) and point-contact methods for detection of chemical, nuclear, biological, nuclear and explosive agents and contaminants in water, to synthesis methods for several materials used for sensors.  In view of asymmetric, kinetic, and distributed nature of threat vectors, an emphasis is placed to examine new generation of sensors/detectors that utilize an ecosystems of innovation and advanced sciences convergence in support of effective counter-measures against  CBRNE threats. The book will be of considerable interest and...

  10. Autonomous Robot System for Sensor Characterization

    Energy Technology Data Exchange (ETDEWEB)

    David Bruemmer; Douglas Few; Frank Carney; Miles Walton; Heather Hunting; Ron Lujan

    2004-03-01

    This paper discusses an innovative application of new Markov localization techniques that combat the problem of odometry drift, allowing a novel control architecture developed at the Idaho National Engineering and Environmental Laboratory (INEEL) to be utilized within a sensor characterization facility developed at the Remote Sensing Laboratory (RSL) in Nevada. The new robotic capability provided by the INEEL will allow RSL to test and evaluate a wide variety of sensors including radiation detection systems, machine vision systems, and sensors that can detect and track heat sources (e.g. human bodies, machines, chemical plumes). By accurately moving a target at varying speeds along designated paths, the robotic solution allows the detection abilities of a wide variety of sensors to be recorded and analyzed.

  11. The impact of MOSFET-based sensors

    NARCIS (Netherlands)

    Bergveld, P.

    1985-01-01

    The basic structure as well as the physical existence of the MOS field-effect transistor is without doubt of great importance for the development of a whole series of sensors for the measurement of physical and chemical environmental parameters. The equation for the MOSFET drain current already sho

  12. Recent Advances in Paper-Based Sensors

    Directory of Open Access Journals (Sweden)

    Edith Chow

    2012-08-01

    Full Text Available Paper-based sensors are a new alternative technology for fabricating simple, low-cost, portable and disposable analytical devices for many application areas including clinical diagnosis, food quality control and environmental monitoring. The unique properties of paper which allow passive liquid transport and compatibility with chemicals/biochemicals are the main advantages of using paper as a sensing platform. Depending on the main goal to be achieved in paper-based sensors, the fabrication methods and the analysis techniques can be tuned to fulfill the needs of the end-user. Current paper-based sensors are focused on microfluidic delivery of solution to the detection site whereas more advanced designs involve complex 3-D geometries based on the same microfluidic principles. Although paper-based sensors are very promising, they still suffer from certain limitations such as accuracy and sensitivity. However, it is anticipated that in the future, with advances in fabrication and analytical techniques, that there will be more new and innovative developments in paper-based sensors. These sensors could better meet the current objectives of a viable low-cost and portable device in addition to offering high sensitivity and selectivity, and multiple analyte discrimination. This paper is a review of recent advances in paper-based sensors and covers the following topics: existing fabrication techniques, analytical methods and application areas. Finally, the present challenges and future outlooks are discussed.

  13. Color Changing Hydrogen Sensors

    Science.gov (United States)

    Roberson, Luke B.; Williams, Martha; Captain, Janine E.; Mohajeri, Nahid; Raissi, Ali

    2015-01-01

    During the Space Shuttle Program, one of the most hazardous operation that occurred was the loading of liquid hydrogen (LH2) during fueling operations of the spacecraft. Due to hydrogen's low explosive limit, any amount leaked could lead to catastrophic event. Hydrogen's chemical properties make it ideal as a rocket fuel; however, the fuel is deemed unsafe for most commercial use because of the inability to easily detect the gas leaking. The increased use of hydrogen over traditional fossil fuels would reduce greenhouse gases and America's dependency on foreign oil. Therefore a technology that would improve safety at NASA and in the commercial sector while creating a new economic sector would have a huge impact to NASA's mission. The Chemochromic Detector for sensing hydrogen gas leakage is a color-changing detector that is useful in any application where it is important to know not only the presence but also the location of the hydrogen gas leak. This technology utilizes a chemochromicpigment and polymer matrix that can be molded or spun into rigid or pliable shapes useable in variable temperature environments including atmospheres of inert gas, hydrogen gas, or mixtures of gases. A change in color of the detector material indicates where gaseous hydrogen leaks are occurring. The irreversible sensor has a dramatic color change from beige to dark grey and remains dark grey after exposure. A reversible pigment changes from white to blue in the presence of hydrogen and reverts back to white in the presence of oxygen. Both versions of the sensor's pigments were comprised of a mixture of a metal oxide substrate and a hydro-chromic compound (i.e., the compound that changed color in the presence of hydrogen) and immediately notified the operator of the presence of low levels of hydrogen. The detector can be used in a variety of formats including paint, tape, caulking, injection molded parts, textiles and fabrics, composites, and films. This technology brings numerous

  14. Sensors for Screening and Surveillance

    Energy Technology Data Exchange (ETDEWEB)

    Dye, D.H.

    2002-03-05

    Much attention, in fact an entire session at this conference, is being devoted to protecting the United States against human threats--individuals who may pose a danger by their mere presence on US soil. However, tomorrow's terrorists will employ weapons in their attacks, and we must also be diligent in preventing these weapons from reaching their targets. Sensors can play an important role in detecting these weapons before they achieve their desired effects. A sensor system can best be understood as a way of automating search techniques that would normally be carried out by a human's touch and vision senses, or by a dog's sniffing capabilities. The list of potential threats is long, including nuclear, biological, chemical and radiological weapons, and each presents its own challenges. However, any effective system must meet the following requirements: (1) Sensor systems must be operationally practical. Delays must be kept to a minimum. The systems must be safe to operate. Individual privacy and corporate proprietary information must be protected. The systems must be part of a viable concept of operations; i.e., they must provide information that can enable effective, preemptive actions to be taken. (2) Sensors systems must be highly sensitive, providing a low probability of missed detections (false negatives). Our adversaries will conceal their device from detection, and they will likely probe our defenses for any weaknesses. Our systems must be robust against these techniques. (3) Sensor systems must give a low probability of false alarms (false positives). Our response to the detection of such a weapon will marshal substantial resources and, in many scenarios, be highly disruptive to the general population. Thus a system that gives frequent false alarms will soon be ignored.

  15. Amorphous Diamond MEMS and Sensors

    Energy Technology Data Exchange (ETDEWEB)

    SULLIVAN, JOHN P.; FRIEDMANN, THOMAS A.; ASHBY, CAROL I.; DE BOER, MAARTEN P.; SCHUBERT, W. KENT; SHUL, RANDY J.; HOHLFELDER, ROBERT J.; LAVAN, D.A.

    2002-06-01

    This report describes a new microsystems technology for the creation of microsensors and microelectromechanical systems (MEMS) using stress-free amorphous diamond (aD) films. Stress-free aD is a new material that has mechanical properties close to that of crystalline diamond, and the material is particularly promising for the development of high sensitivity microsensors and rugged and reliable MEMS. Some of the unique properties of aD include the ability to easily tailor film stress from compressive to slightly tensile, hardness and stiffness 80-90% that of crystalline diamond, very high wear resistance, a hydrophobic surface, extreme chemical inertness, chemical compatibility with silicon, controllable electrical conductivity from insulating to conducting, and biocompatibility. A variety of MEMS structures were fabricated from this material and evaluated. These structures included electrostatically-actuated comb drives, micro-tensile test structures, singly- and doubly-clamped beams, and friction and wear test structures. It was found that surface micromachined MEMS could be fabricated in this material easily and that the hydrophobic surface of the film enabled the release of structures without the need for special drying procedures or the use of applied hydrophobic coatings. Measurements using these structures revealed that aD has a Young's modulus of {approx}650 GPa, a tensile fracture strength of 8 GPa, and a fracture toughness of 8 MPa{center_dot}m {sup 1/2}. These results suggest that this material may be suitable in applications where stiction or wear is an issue. Flexural plate wave (FPW) microsensors were also fabricated from aD. These devices use membranes of aD as thin as {approx}100 nm. The performance of the aD FPW sensors was evaluated for the detection of volatile organic compounds using ethyl cellulose as the sensor coating. For comparable membrane thicknesses, the aD sensors showed better performance than silicon nitride based sensors. Greater

  16. Air Sensor Toolbox

    Science.gov (United States)

    Air Sensor Toolbox provides information to citizen scientists, researchers and developers interested in learning more about new lower-cost compact air sensor technologies and tools for measuring air quality.

  17. Towards Sensor Database Systems

    DEFF Research Database (Denmark)

    Bonnet, Philippe; Gehrke, Johannes; Seshadri, Praveen

    2001-01-01

    Sensor networks are being widely deployed for measurement, detection and surveillance applications. In these new applications, users issue long-running queries over a combination of stored data and sensor data. Most existing applications rely on a centralized system for collecting sensor data....... These systems lack flexibility because data is extracted in a predefined way; also, they do not scale to a large number of devices because large volumes of raw data are transferred regardless of the queries that are submitted. In our new concept of sensor database system, queries dictate which data is extracted...... from the sensors. In this paper, we define the concept of sensor databases mixing stored data represented as relations and sensor data represented as time series. Each long-running query formulated over a sensor database defines a persistent view, which is maintained during a given time interval. We...

  18. Embedded sensor systems

    CERN Document Server

    Agrawal, Dharma Prakash

    2017-01-01

    This inspiring textbook provides an introduction to wireless technologies for sensors, explores potential use of sensors for numerous applications, and utilizes probability theory and mathematical methods as a means of embedding sensors in system design. It discusses the need for synchronization and underlying limitations, inter-relation between given coverage and connectivity to number of sensors needed, and the use of geometrical distance to determine location of the base station for data collection and explore use of anchor nodes for relative position determination of sensors. The book explores energy conservation, communication using TCP, the need for clustering and data aggregation, and residual energy determination and energy harvesting. It covers key topics of sensor communication like mobile base stations and relay nodes, delay-tolerant sensor networks, and remote sensing and possible applications. The book defines routing methods and do performance evaluation for random and regular sensor topology an...

  19. EDITORIAL: Nanotechnology impact on sensors Nanotechnology impact on sensors

    Science.gov (United States)

    Brugger, Jürgen

    2009-10-01

    A sensor is a device that responds to a stimulus by generating a functional output induced by a change in some intrinsic properties. We are surrounded by sensors and sensing networks that monitor a multitude of parameters in view of enhancing our safety and quality of life. Sensors assist us in health care and diagnostics, they monitor our environment, our aeroplanes and automobiles, our mobile phones, game consoles and watches, and last but not least, many of our human body functions. Modern sensing systems have greatly benefited in recent decades from advances in microelectronics and microengineering, mainly in view of making sensors smaller, cheaper, more sensitive, more selective, and with a better signal-to-noise ratio, following classical scaling rules. So how about nanotechnology-enabled sensing? Nanoscale features have a great impact on many (though not all) sensing systems, in particular where the surface-to-volume ratio plays a fundamental role, such as in certain chemical and gas sensors. The high surface-to-volume ratios of nanoporous and nanostructured materials have led to their implementation in sensing systems since sensing research first began to engage with the nanotechnology. The surface plasmon resonances of nanostructures have also enriched the scope for developing novel sensing devices. On the other hand, sensors where bulk properties dominate, such as inertial sensors, are less likely to benefit from extreme scaling. Advances in thin film techniques and chemical synthesis have allowed material properties to be tailored to sensing requirements for enhanced performance. These bottom-up fabrication techniques enable parallel fabrication of ordered nanostructures, often in domain-like areas with molecular precision. At the same time the progress in top-down methods such as scanning probe lithography, nanoimprint lithography, soft-lithography and stencil lithography have also facilitated research into sensing and actuating nanotechnology. Although

  20. Digital Sensor Technology

    Energy Technology Data Exchange (ETDEWEB)

    Ted Quinn; Jerry Mauck; Richard Bockhorst; Ken Thomas

    2013-07-01

    The nuclear industry has been slow to incorporate digital sensor technology into nuclear plant designs due to concerns with digital qualification issues. However, the benefits of digital sensor technology for nuclear plant instrumentation are substantial in terms of accuracy, reliability, availability, and maintainability. This report demonstrates these benefits in direct comparisons of digital and analog sensor applications. It also addresses the qualification issues that must be addressed in the application of digital sensor technology.

  1. Fiber optic geophysical sensors

    Science.gov (United States)

    Homuth, Emil F.

    1991-01-01

    A fiber optic geophysical sensor in which laser light is passed through a sensor interferometer in contact with a geophysical event, and a reference interferometer not in contact with the geophysical event but in the same general environment as the sensor interferometer. In one embodiment, a single tunable laser provides the laser light. In another embodiment, separate tunable lasers are used for the sensor and reference interferometers. The invention can find such uses as monitoring for earthquakes, and the weighing of objects.

  2. Sensors for Entertainment

    Science.gov (United States)

    Lamberti, Fabrizio; Sanna, Andrea; Rokne, Jon

    2016-01-01

    Sensors are becoming ubiquitous in all areas of science, technology, and society. In this Special Issue on “Sensors for Entertainment”, developments in progress and the current state of application scenarios for sensors in the field of entertainment is explored. PMID:27428981

  3. Optical waveguide sensors

    NARCIS (Netherlands)

    Fluitman, J.; Popma, Th.

    1986-01-01

    An overview of the field of optical waveguide sensors is presented. Some emphasis is laid on the development of a single scheme under which the diversity of sensor principles can be arranged. First three types of sensors are distinguished: intrinsic, extrinsic and active. Next, two steps are disting

  4. Environmental Sensor Networks

    OpenAIRE

    Martinez, Kirk; Hart, Jane; Ong, Royan

    2004-01-01

    Sensor networks for the natural environment require an understanding of earth science, combined with sensor, communications and computer technology. We discuss the evolution from data logging to sensor networks, describe our research from a glacial environment and highlight future challenges in this field.

  5. Automotive vehicle sensors

    Energy Technology Data Exchange (ETDEWEB)

    Sheen, S.H.; Raptis, A.C.; Moscynski, M.J.

    1995-09-01

    This report is an introduction to the field of automotive vehicle sensors. It contains a prototype data base for companies working in automotive vehicle sensors, as well as a prototype data base for automotive vehicle sensors. A market analysis is also included.

  6. Thermal flow micro sensors

    NARCIS (Netherlands)

    Elwenspoek, M.

    1999-01-01

    A review is given on sensors fabricated by silicon micromachining technology using the thermal domain for the measurement of fluid flow. Attention is paid especially to performance and geometry of the sensors. Three basic types of thermal flow sensors are discussed: anemometers, calorimetric flow se

  7. Sensors and actuators, Twente

    NARCIS (Netherlands)

    Bergveld, P.

    1989-01-01

    This paper describes the organization and the research programme of the Sensor and Actuator (S&A) Research Unit of the University of Twente, Enschede, the Netherlands. It includes short descriptions of all present projects concerning: micromachined mechanical sensors and actuators, optical sensors,

  8. Sensors for Entertainment

    Directory of Open Access Journals (Sweden)

    Fabrizio Lamberti

    2016-07-01

    Full Text Available Sensors are becoming ubiquitous in all areas of science, technology, and society. In this Special Issue on “Sensors for Entertainment”, developments in progress and the current state of application scenarios for sensors in the field of entertainment is explored.

  9. Nanomaterial Based Sensors for NASA Missions

    Science.gov (United States)

    Koehne, Jessica E.

    2016-01-01

    Nanomaterials such as carbon nanotubes (CNTs), carbon nanofibers (CNFs), graphene and metal nanowires have shown interesting electronic properties and therefore have been pursued for a variety of space applications requiring ultrasensitive and light-weight sensor and electronic devices. We have been pursuing development of chemical and biosensors using carbon nanotubes and carbon nanofibers for the last several years and this talk will present the benefits of nanomaterials these applications. More recently, printing approaches to manufacturing these devices have been explored as a strategy that is compatible to a microgravity environment. Nanomaterials are either grown in house or purchased and processed as electrical inks. Chemical modification or coatings are added to the nanomaterials to tailor the nanomaterial to the exact application. The development of printed chemical sensors and biosensors will be discussed for applications ranging from crew life support to exploration missions.

  10. Virtual Sensor Test Instrumentation

    Science.gov (United States)

    Wang, Roy

    2011-01-01

    Virtual Sensor Test Instrumentation is based on the concept of smart sensor technology for testing with intelligence needed to perform sell-diagnosis of health, and to participate in a hierarchy of health determination at sensor, process, and system levels. A virtual sensor test instrumentation consists of five elements: (1) a common sensor interface, (2) microprocessor, (3) wireless interface, (4) signal conditioning and ADC/DAC (analog-to-digital conversion/ digital-to-analog conversion), and (5) onboard EEPROM (electrically erasable programmable read-only memory) for metadata storage and executable software to create powerful, scalable, reconfigurable, and reliable embedded and distributed test instruments. In order to maximize the efficient data conversion through the smart sensor node, plug-and-play functionality is required to interface with traditional sensors to enhance their identity and capabilities for data processing and communications. Virtual sensor test instrumentation can be accessible wirelessly via a Network Capable Application Processor (NCAP) or a Smart Transducer Interlace Module (STIM) that may be managed under real-time rule engines for mission-critical applications. The transducer senses the physical quantity being measured and converts it into an electrical signal. The signal is fed to an A/D converter, and is ready for use by the processor to execute functional transformation based on the sensor characteristics stored in a Transducer Electronic Data Sheet (TEDS). Virtual sensor test instrumentation is built upon an open-system architecture with standardized protocol modules/stacks to interface with industry standards and commonly used software. One major benefit for deploying the virtual sensor test instrumentation is the ability, through a plug-and-play common interface, to convert raw sensor data in either analog or digital form, to an IEEE 1451 standard-based smart sensor, which has instructions to program sensors for a wide variety of

  11. Chemical use

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a summary of research and activities related to chemical use on Neal Smith National Wildlife Refuge between 1992 and 2009. The chemicals used on the Refuge...

  12. Chemical Reactors.

    Science.gov (United States)

    Kenney, C. N.

    1980-01-01

    Describes a course, including content, reading list, and presentation on chemical reactors at Cambridge University, England. A brief comparison of chemical engineering education between the United States and England is also given. (JN)

  13. Multifuctional integrated sensors (MFISES).

    Energy Technology Data Exchange (ETDEWEB)

    Homeijer, Brian D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Roozeboom, Clifton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-10-01

    Many emerging IoT applications require sensing of multiple physical and environmental parameters for: completeness of information, measurement validation, unexpected demands, improved performance. For example, a typical outdoor weather station measures temperature, humidity, barometric pressure, light intensity, rainfall, wind speed and direction. Existing sensor technologies do not directly address the demand for cost, size, and power reduction in multi-paramater sensing applications. Industry sensor manufacturers have developed integrated sensor systems for inertial measurements that combine accelerometers, gyroscopes, and magnetometers, but do not address environmental sensing functionality. In existing research literature, a technology gap exists between the functionality of MEMS sensors and the real world applications of the sensors systems.

  14. Long Wave Infrared Cavity Enhanced Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Taubman, Matthew S.; Scott, David C.; Cannon, Bret D.; Myers, Tanya L.; Bonebrake, Christopher A.; Aker, Pam M.; Wojcik, Michael D.; Munley, John T.; Nguyen, Vinh T.; Schultz, John F.

    2004-10-01

    The principal goal of Pacific Northwest National Laboratory's (PNNL's) long wave infrared (LWIR) cavity enhanced sensor (CES) project is to explore ultra-sensitive spectroscopic techniques and apply them to the development of LWIR chemical sensors needed for detecting weapons proliferation. This includes detecting not only the weapons of mass destruction (WMDs) themselves, but also signatures of their production and/or detonation. The LWIR CES project is concerned exclusively with developing point sensors; other portions of PNNL's IR Sensors program address stand off detection. PNNL's LWIR CES research is distinguished from that done by others by the use quantum cascade lasers (QCLs) as the light source. QCLs are novel devices, and a significant fraction of our research has been devoted to developing the procedures and hardware required to implement them most effectively for chemical sensing. This report details the progress we have made on our LWIR CES sensor development. During FY02, PNNL investigated three LWIR CES implementations beginning with the easiest to implement, direct cavity-enhanced detection (simple CES), including a technique of intermediate difficulty, cavity-dithered phase-sensitive detection (FM recovery CES) through to the most complex technique, that of resonant sideband cavity-enhanced detection also known as noise-immune cavity-enhanced optical heterodyne molecular spectroscopy, or NICE-OHMS.

  15. Sensor mount assemblies and sensor assemblies

    Science.gov (United States)

    Miller, David H [Redondo Beach, CA

    2012-04-10

    Sensor mount assemblies and sensor assemblies are provided. In an embodiment, by way of example only, a sensor mount assembly includes a busbar, a main body, a backing surface, and a first finger. The busbar has a first end and a second end. The main body is overmolded onto the busbar. The backing surface extends radially outwardly relative to the main body. The first finger extends axially from the backing surface, and the first finger has a first end, a second end, and a tooth. The first end of the first finger is disposed on the backing surface, and the tooth is formed on the second end of the first finger.

  16. MEMS optical sensor

    DEFF Research Database (Denmark)

    2013-01-01

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

  17. Silicon force sensor

    Science.gov (United States)

    Galambos, Paul C.; Crenshaw, Thomas B.; Nishida, Erik E.; Burnett, Damon J.; Lantz, Jeffrey W.

    2016-07-05

    The various technologies presented herein relate to a sensor for measurement of high forces and/or high load shock rate(s), whereby the sensor utilizes silicon as the sensing element. A plate of Si can have a thinned region formed therein on which can be formed a number of traces operating as a Wheatstone bridge. The brittle Si can be incorporated into a layered structure comprising ductile and/or compliant materials. The sensor can have a washer-like configuration which can be incorporated into a nut and bolt configuration, whereby tightening of the nut and bolt can facilitate application of a compressive preload upon the sensor. Upon application of an impact load on the bolt, the compressive load on the sensor can be reduced (e.g., moves towards zero-load), however the magnitude of the preload can be such that the load on the sensor does not translate to tensile stress being applied to the sensor.

  18. Online Distributed Sensor Selection

    CERN Document Server

    Golovin, Daniel; Krause, Andreas

    2010-01-01

    A key problem in sensor networks is to decide which sensors to query when, in order to obtain the most useful information (e.g., for performing accurate prediction), subject to constraints (e.g., on power and bandwidth). In many applications the utility function is not known a priori, must be learned from data, and can even change over time. Furthermore for large sensor networks solving a centralized optimization problem to select sensors is not feasible, and thus we seek a fully distributed solution. In this paper, we present Distributed Online Greedy (DOG), an efficient, distributed algorithm for repeatedly selecting sensors online, only receiving feedback about the utility of the selected sensors. We prove very strong theoretical no-regret guarantees that apply whenever the (unknown) utility function satisfies a natural diminishing returns property called submodularity. Our algorithm has extremely low communication requirements, and scales well to large sensor deployments. We extend DOG to allow observatio...

  19. Fabrication of High Sensitivity Carbon Microcoil Pressure Sensors

    Directory of Open Access Journals (Sweden)

    Shuo-Hung Chang

    2012-07-01

    Full Text Available This work demonstrates a highly sensitive pressure sensor that was fabricated using carbon microcoils (CMCs and polydimethylsiloxane (PDMS. CMCs were grown by chemical vapor deposition using various ratios of Fe-Sn catalytic solution. The pressure sensor has a sandwiched structure, in which the as-grown CMCs were inserted between two PDMS layers. The pressure sensor exhibits piezo-resistivity changes in response to mechanical loading using a load cell system. The yields of the growth of CMCs at a catalyst proportion of Fe:Sn = 95:5 reach 95%. Experimental results show that the sensor achieves a high sensitivity of 0.93%/kPa from the CMC yield of 95%. The sensitivity of the pressure sensor increases with increasing yield of CMCs. The demonstrated pressure sensor shows the advantage of high sensitivity and is suitable for mass production.

  20. Integrated chemiresistor array for small sensor platforms

    Energy Technology Data Exchange (ETDEWEB)

    HUGHES,ROBERT C.; CASALNUOVO,STEPHEN A.; WESSENDORF,KURT O.; SAVIGNON,DANIEL J.; HIETALA,SUSAN LESLIE; PATEL,SANJAY V.

    2000-04-13

    Chemiresistors are fabricated from materials that change their electrical resistance when exposed to certain chemical species. Composites of soluble polymers with metallic particles have shown remarkable sensitivity to many volatile organic chemicals, depending on the ability of the analyte molecules to swell the polymer matrix. These sensors can be made extremely small (< 100 square microns), operate at ambient temperatures, and require almost no power to read-out. However, the chemiresistor itself is only a part of a more complex sensor system that delivers chemical information to a user who can act on the information. The authors present the design, fabrication and performance of a chemiresistor array chip with four different chemiresistor materials, heaters and a temperature sensor. They also show the design and fabrication of an integrated chemiresistor array, where the electronics to read-out the chemiresistors is on the same chip with the electrodes for the chemiresistors. The circuit was designed to perform several functions to make the sensor data more useful. This low-power, integrated chemiresistor array is small enough to be deployed on a Sandia-developed microrobot platform.

  1. Mitochondrially targeted fluorescent redox sensors.

    Science.gov (United States)

    Yang, Kylie; Kolanowski, Jacek L; New, Elizabeth J

    2017-04-06

    The balance of oxidants and antioxidants within the cell is crucial for maintaining health, and regulating physiological processes such as signalling. Consequently, imbalances between oxidants and antioxidants are now understood to lead to oxidative stress, a physiological feature that underlies many diseases. These processes have spurred the field of chemical biology to develop a plethora of sensors, both small-molecule and fluorescent protein-based, for the detection of specific oxidizing species and general redox balances within cells. The mitochondrion, in particular, is the site of many vital redox reactions. There is therefore a need to target redox sensors to this particular organelle. It has been well established that targeting mitochondria can be achieved by the use of a lipophilic cation-targeting group, or by utilizing natural peptidic mitochondrial localization sequences. Here, we review how these two approaches have been used by a number of researchers to develop mitochondrially localized fluorescent redox sensors that are already proving useful in providing insights into the roles of reactive oxygen species in the mitochondria.

  2. Photonics crystal fiber Raman sensors

    Science.gov (United States)

    Yang, Xuan; Bond, Tiziana C.; Zhang, Jin Z.; Li, Yat; Gu, Claire

    2012-11-01

    Hollow core photonic crystal fiber (HCPCF) employs a guiding mechanism fundamentally different from that in conventional index guiding fibers. In an HCPCF, periodic air channels in a glass matrix act as reflectors to confine light in an empty core. As a result, the interaction between light and glass can be very small. Therefore, HCPCF has been used in applications that require extremely low non-linearity, high breakdown threshold, and zero dispersion. However, their applications in optical sensing, especially in chemical and biological sensing, have only been extensively explored recently. Besides their well-recognized optical properties the hollow cores of the fibers can be easily filled with liquid or gas, providing an ideal sampling mechanism in sensors. Recently, we have demonstrated that by filling up a HCPCF with gas or liquid samples, it is possible to significantly increase the sensitivity of the sensors in either regular Raman or surface enhanced Raman scattering (SERS) applications. This is because the confinement of both light and sample inside the hollow core enables direct interaction between the propagating wave and the analyte. In this paper, we report our recent work on using HCPCF as a platform for Raman or SERS in the detection of low concentration greenhouse gas (ambient CO2), biomedically significant molecules (e.g., glucose), and bacteria. We have demonstrated that by filling up a HCPCF with gas or liquid samples, it is possible to significantly increase the sensitivity of the sensors in either regular Raman or SERS applications.

  3. Digital Sensor Technology

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Ken D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Quinn, Edward L. [Technology Resources, Dana Point, CA (United States); Mauck, Jerry L. [Technology Resources, Dana Point, CA (United States); Bockhorst, Richard M. [Technology Resources, Dana Point, CA (United States)

    2015-02-01

    The nuclear industry has been slow to incorporate digital sensor technology into nuclear plant designs due to concerns with digital qualification issues. However, the benefits of digital sensor technology for nuclear plant instrumentation are substantial in terms of accuracy and reliability. This paper, which refers to a final report issued in 2013, demonstrates these benefits in direct comparisons of digital and analog sensor applications. Improved accuracy results from the superior operating characteristics of digital sensors. These include improvements in sensor accuracy and drift and other related parameters which reduce total loop uncertainty and thereby increase safety and operating margins. An example instrument loop uncertainty calculation for a pressure sensor application is presented to illustrate these improvements. This is a side-by-side comparison of the instrument loop uncertainty for both an analog and a digital sensor in the same pressure measurement application. Similarly, improved sensor reliability is illustrated with a sample calculation for determining the probability of failure on demand, an industry standard reliability measure. This looks at equivalent analog and digital temperature sensors to draw the comparison. The results confirm substantial reliability improvement with the digital sensor, due in large part to ability to continuously monitor the health of a digital sensor such that problems can be immediately identified and corrected. This greatly reduces the likelihood of a latent failure condition of the sensor at the time of a design basis event. Notwithstanding the benefits of digital sensors, there are certain qualification issues that are inherent with digital technology and these are described in the report. One major qualification impediment for digital sensor implementation is software common cause failure (SCCF).

  4. Advances in miniature spectrometer and sensor development

    Science.gov (United States)

    Malinen, Jouko; Rissanen, Anna; Saari, Heikki; Karioja, Pentti; Karppinen, Mikko; Aalto, Timo; Tukkiniemi, Kari

    2014-05-01

    Miniaturization and cost reduction of spectrometer and sensor technologies has great potential to open up new applications areas and business opportunities for analytical technology in hand held, mobile and on-line applications. Advances in microfabrication have resulted in high-performance MEMS and MOEMS devices for spectrometer applications. Many other enabling technologies are useful for miniature analytical solutions, such as silicon photonics, nanoimprint lithography (NIL), system-on-chip, system-on-package techniques for integration of electronics and photonics, 3D printing, powerful embedded computing platforms, networked solutions as well as advances in chemometrics modeling. This paper will summarize recent work on spectrometer and sensor miniaturization at VTT Technical Research Centre of Finland. Fabry-Perot interferometer (FPI) tunable filter technology has been developed in two technical versions: Piezoactuated FPIs have been applied in miniature hyperspectral imaging needs in light weight UAV and nanosatellite applications, chemical imaging as well as medical applications. Microfabricated MOEMS FPIs have been developed as cost-effective sensor platforms for visible, NIR and IR applications. Further examples of sensor miniaturization will be discussed, including system-on-package sensor head for mid-IR gas analyzer, roll-to-roll printed Surface Enhanced Raman Scattering (SERS) technology as well as UV imprinted waveguide sensor for formaldehyde detection.

  5. Pristine carbon nanotubes based resistive temperature sensor

    Science.gov (United States)

    Alam, Md Bayazeed; Saini, Sudhir Kumar; Sharma, Daya Shankar; Agarwal, Pankaj B.

    2016-04-01

    A good sensor must be highly sensitive, faster in response, of low cost cum easily producible, and highly reliable. Incorporation of nano-dimensional particles/ wires makes conventional sensors more effective in terms of fulfilling the above requirements. For example, Carbon Nanotubes (CNTs) are promising sensing element because of its large aspect ratio, unique electronic and thermal properties. In addition to their use for widely reported chemical sensing, it has also been explored for temperature sensing. This paper presents the fabrication of CNTs based temperature sensor, prepared on silicon substrate using low cost spray coating method, which is reliable and reproducible method to prepare uniform CNTs thin films on any substrate. Besides this, simple and inexpensive method of preparation of dispersion of single walled CNTs (SWNTs) in 1,2 dichlorobenzene by using probe type ultrasonicator for debundling the CNTs for improving sensor response were used. The electrical contacts over the dispersed SWNTs were taken using silver paste electrodes. Fabricated sensors clearly show immediate change in resistance as a response to change in temperature of SWNTs. The measured sensitivity (change in resistance with temperature) of the sensor was found ˜ 0.29%/°C in the 25°C to 60°C temperature range.

  6. Bimodular high temperature planar oxygen gas sensor

    Directory of Open Access Journals (Sweden)

    Xiangcheng eSun

    2014-08-01

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

  7. Fiber Bragg grating sensors: a market overview

    Science.gov (United States)

    Méndez, A.

    2007-07-01

    Over the last few years, optical fiber sensors have seen increased acceptance and widespread use. Among the multitude of sensor types, FBG based sensors, more than any other particular sensor type, have become widely known and popular. Given their intrinsic capability to measure a multitude of parameters such as strain, temperature, pressure, chemical and biological agents - and many others - coupled with their flexibility of design to be used as single point or multi-point sensing arrays and their relative low cost, make of FBGs ideal devices to be adopted for a multitude of different sensing applications and implemented in different fields and industries. However, some technical hurdles and market barriers need to be overcome in order for this technology - and fiber sensors in general - to gain more commercial momentum and achieve faster market growth such as the need for industry standards on FBGs and FBG-based sensors, adequate packaging designs, as well as training and education of prospective customers and end-users.

  8. Testing integrated sensors for cooperative remote monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Filby, E.E.; Smith, T.E.; Albano, R.K.; Andersen, M.K. [Idaho National Engineering Lab., Idaho Falls, ID (United States); Lucero, R.L.; Tolk, K.M.; Andrews, N.S. [Sandia National Lab., Albuquerque, NM (United States)

    1996-12-31

    The Modular Integrated Monitoring System (MIMS) program, with Sandia National Laboratory (SNL) as the lead lab, was devised to furnish sensors and integrated multi-sensor systems for cooperative remote monitoring. The Idaho National Engineering Laboratory (INEL), via the Center for Integrated Monitoring and Control (CIMC), provides realistic field tests of the sensors and sensor-integration approach for the MIMS, and for other similar programs. This has two important goals: it helps insure that these systems are truly read for use, and provides a platform so they can be demonstrated for potential users. A remote monitoring test/demonstration has been initiated at the Idaho Chemical Processing Plant (ICPP) to track the movement of spent nuclear fuel from one storage location to another, using a straddle carrier and shielded cask combination. Radiation monitors, motion sensors, videocameras, and other devices from several US Department of Energy (DOE) labs and commercial vendors were linked on the network. Currently, project personnel are collecting raw data from this large array of sensors, without trying to program any special network activities or other responses. These data will be used to determine which devices can actually provide useful information for a cooperative monitoring situation, versus those that may be redundant.

  9. Wearable electrochemical sensors for monitoring performance athletes

    Science.gov (United States)

    Fraser, Kevin J.; Curto, Vincenzo F.; Coyle, Shirley; Schazmann, Benjamin; Byrne, Robert; Benito-Lopez, Fernando; Owens, Róisín M.; Malliaras, George G.; Diamond, Dermot

    2011-10-01

    Nowadays, wearable sensors such as heart rate monitors and pedometers are in common use. The use of wearable systems such as these for personalized exercise regimes for health and rehabilitation is particularly interesting. In particular, the true potential of wearable chemical sensors, which for the real-time ambulatory monitoring of bodily fluids such as tears, sweat, urine and blood has not been realized. Here we present a brief introduction into the fields of ionogels and organic electrochemical transistors, and in particular, the concept of an OECT transistor incorporated into a sticking-plaster, along with a printable "ionogel" to provide a wearable biosensor platform.

  10. Integrated Microfluidic Sensor System with Magnetostrictive Resonators

    KAUST Repository

    Liang, Cai

    2011-12-08

    The present embodiments describe a method that integrates a magnetostrictive sensor with driving and detecting elements into a microfluidic chip to detect a chemical, biochemical or biomedical species. These embodiments may also measure the properties of a fluid such as viscosity, pH values. The whole system can be referred to lab-on-a-chip (LOC) or micro-total-analysis-systems (.mu.TAS). In particular, this present embodiments include three units, including a microfluidics unit, a magnetostrictive sensor, and driving/detecting elements. An analyzer may also be provided to analyze an electrical signal associated with a feature of a target specimen.

  11. Wireless Sensor Applications in Extreme Aeronautical Environments

    Science.gov (United States)

    Wilson, William C.; Atkinson, Gary M.

    2013-01-01

    NASA aeronautical programs require rigorous ground and flight testing. Many of the testing environments can be extremely harsh. These environments include cryogenic temperatures and high temperatures (greater than 1500 C). Temperature, pressure, vibration, ionizing radiation, and chemical exposure may all be part of the harsh environment found in testing. This paper presents a survey of research opportunities for universities and industry to develop new wireless sensors that address anticipated structural health monitoring (SHM) and testing needs for aeronautical vehicles. Potential applications of passive wireless sensors for ground testing and high altitude aircraft operations are presented. Some of the challenges and issues of the technology are also presented.

  12. Fluorescence Resonance Energy Transfer (FRET) sensor

    CERN Document Server

    Hussain, Syed Arshad; Chakraborty, Sekhar; Saha, Jaba; Roy, Arpan Datta; Chakraborty, Santanu; Debnath, Pintu; Bhattacharjee, D

    2014-01-01

    The applications of Fluorescence resonance energy transfer (FRET) have expanded tremendously in the last 25 years, and the technique has become a staple technique in many biological and biophysical fields. FRET can be used as spectroscopic ruler in various areas such as structural elucidation of biological molecules and their interactions, in vitro assays, in vivo monitoring in cellular research, nucleic acid analysis, signal transduction, light harvesting, and metallic nanomaterials etc. Based on the mechanism of FRET a variety of novel chemical sensors and Biosensors have been developed. This review highlights the recent applications of sensitive and selective ratiometric FRET based sensors.

  13. HEAT Sensor: Harsh Environment Adaptable Thermionic Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Limb, Scott J. [Palo Alto Research Center, Palo Alto, CA (United States)

    2016-05-31

    This document is the final report for the “HARSH ENVIRONMENT ADAPTABLE THERMIONIC SENSOR” project under NETL’s Crosscutting contract DE-FE0013062. This report addresses sensors that can be made with thermionic thin films along with the required high temperature hermetic packaging process. These sensors can be placed in harsh high temperature environments and potentially be wireless and self-powered.

  14. Sensor Management for Tracking in Sensor Networks

    CERN Document Server

    Fuemmeler, Jason A; Veeravalli, Venugopal V

    2010-01-01

    We study the problem of tracking an object moving through a network of wireless sensors. In order to conserve energy, the sensors may be put into a sleep mode with a timer that determines their sleep duration. It is assumed that an asleep sensor cannot be communicated with or woken up, and hence the sleep duration needs to be determined at the time the sensor goes to sleep based on all the information available to the sensor. Having sleeping sensors in the network could result in degraded tracking performance, therefore, there is a tradeoff between energy usage and tracking performance. We design sleeping policies that attempt to optimize this tradeoff and characterize their performance. As an extension to our previous work in this area [1], we consider generalized models for object movement, object sensing, and tracking cost. For discrete state spaces and continuous Gaussian observations, we derive a lower bound on the optimal energy-tracking tradeoff. It is shown that in the low tracking error regime, the g...

  15. Sensor for metal detection

    KAUST Repository

    Kodzius, Rimantas

    2014-06-26

    NOVELTY - The sensor has a microfluidic flow channel that is provided with an inlet port, an outlet port, and a detection chamber. The detection chamber is provided with a group of sensing electrodes (4) having a working electrode (8), a counter electrode (9), and a reference electrode (10). A flow sensor is configured to measure flow in the channel. A temperature sensor (6) is configured to measure temperature in the channel (3). An electrical connection is configured to connect the sensor to a sensing device. USE - Sensor for detecting metal such as toxic metal in sample such as clinical sample such as stool, saliva, sputum, bronchial lavage, urine, vaginal swab, nasal swab, biopsy, tissue, tears, breath, blood, serum, plasma, cerebrospinal fluid, peritoneal fluid, pleural fluid, pericardial fluid, joint fluid, and amniotic fluid, water sample, food sample, air sample, and soil sample (all claimed). ADVANTAGE - The sensor for use with the portable analytical instrument is configured for detection of metalsin samples. The sensor can provide the excellent solution for on-site metal detection, including heavy metal detection. The sensors can provide significant advantages in higher throughput, lower cost, at the same time being less labor intensive and less dependent on individual skills. The disposable design of the sensor, the enhanced reliability and repeatability of measurements can be obtained. The sensors can be widely applied in various industries. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a system for detecting metal in sample; and (2) a method for using sensor for detecting metal in sample. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the sensor prototype. Channel (3) Sensing electrodes (4) Temperature sensor (6) Working electrode (8) Counter electrode (9) Reference electrode (10)

  16. MITRE sensor layer prototype

    Science.gov (United States)

    Duff, Francis; McGarry, Donald; Zasada, David; Foote, Scott

    2009-05-01

    The MITRE Sensor Layer Prototype is an initial design effort to enable every sensor to help create new capabilities through collaborative data sharing. By making both upstream (raw) and downstream (processed) sensor data visible, users can access the specific level, type, and quantities of data needed to create new data products that were never anticipated by the original designers of the individual sensors. The major characteristic that sets sensor data services apart from typical enterprise services is the volume (on the order of multiple terabytes) of raw data that can be generated by most sensors. Traditional tightly coupled processing approaches extract pre-determined information from the incoming raw sensor data, format it, and send it to predetermined users. The community is rapidly reaching the conclusion that tightly coupled sensor processing loses too much potentially critical information.1 Hence upstream (raw and partially processed) data must be extracted, rapidly archived, and advertised to the enterprise for unanticipated uses. The authors believe layered sensing net-centric integration can be achieved through a standardize-encapsulate-syndicateaggregate- manipulate-process paradigm. The Sensor Layer Prototype's technical approach focuses on implementing this proof of concept framework to make sensor data visible, accessible and useful to the enterprise. To achieve this, a "raw" data tap between physical transducers associated with sensor arrays and the embedded sensor signal processing hardware and software has been exploited. Second, we encapsulate and expose both raw and partially processed data to the enterprise within the context of a service-oriented architecture. Third, we advertise the presence of multiple types, and multiple layers of data through geographic-enabled Really Simple Syndication (GeoRSS) services. These GeoRSS feeds are aggregated, manipulated, and filtered by a feed aggregator. After filtering these feeds to bring just the type

  17. The Ringcore Fluxgate Sensor

    DEFF Research Database (Denmark)

    Brauer, Peter

    1997-01-01

    A model describing the fundamental working principle of the "ringcore fluxgate sensor" is derived. The model is solely based on geometrical and measurable magnetic properties of the sensor and from this a number of fluxgate phenomenon can be described and estimated. The sensitivity of ringcore...... fluxgate sensors is measured for a large variety of geometries and is for all measurements found to fall between two limits obtained by the fluxgate model. The model is used to explain the zero field odd harmonic output of the fluxgate sensor, called the "feedthrough". By assuming a non ideal sensor...... with spatially distributed magnetization, the model predicts feedthrough signals which exactly reflects the measured signals. The non-linearities in a feedback compensated ringcore fluxgate sensors, called the "transverse field effect", can also be explained by the model. Measurements on stress annealed...

  18. Flexible magnetoimpedance sensor

    KAUST Repository

    Li, Bodong

    2015-03-01

    Flexible magnetoimpedance (MI) sensors fabricated using a NiFe/Cu/NiFe tri-layer on Kapton substrate have been studied. A customized flexible microstrip transmission line was employed to investigate the MI sensors\\'s magnetic field and frequency responses and their dependence on the sensors\\'s deflection. For the first time, the impedance characteristic is obtained through reflection coefficient analysis over a wide range of frequencies from 0.1 MHz to 3 GHz and for deflections ranging from zero curvature to a radius of 7.2 cm. The sensor element maintains a high MI ratio of up to 90% and magnetic sensitivity of up to 9.2%/Oe over different bending curvatures. The relationship between the curvature and material composition is discussed based on the magnetostriction effect and stress simulations. The sensor\\'s large frequency range, simple fabrication process and high sensitivity provide a great potential for flexible electronics and wireless applications.

  19. Working Group Report: Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Artuso, M.; et al.,

    2013-10-18

    Sensors play a key role in detecting both charged particles and photons for all three frontiers in Particle Physics. The signals from an individual sensor that can be used include ionization deposited, phonons created, or light emitted from excitations of the material. The individual sensors are then typically arrayed for detection of individual particles or groups of particles. Mounting of new, ever higher performance experiments, often depend on advances in sensors in a range of performance characteristics. These performance metrics can include position resolution for passing particles, time resolution on particles impacting the sensor, and overall rate capabilities. In addition the feasible detector area and cost frequently provides a limit to what can be built and therefore is often another area where improvements are important. Finally, radiation tolerance is becoming a requirement in a broad array of devices. We present a status report on a broad category of sensors, including challenges for the future and work in progress to solve those challenges.

  20. Magnetic current sensor

    Science.gov (United States)

    Black, Jr., William C. (Inventor); Hermann, Theodore M. (Inventor)

    1998-01-01

    A current determiner having an output at which representations of input currents are provided having an input conductor for the input current and a current sensor supported on a substrate electrically isolated from one another but with the sensor positioned in the magnetic fields arising about the input conductor due to any input currents. The sensor extends along the substrate in a direction primarily perpendicular to the extent of the input conductor and is formed of at least a pair of thin-film ferromagnetic layers separated by a non-magnetic conductive layer. The sensor can be electrically connected to a electronic circuitry formed in the substrate including a nonlinearity adaptation circuit to provide representations of the input currents of increased accuracy despite nonlinearities in the current sensor, and can include further current sensors in bridge circuits.

  1. Clementine sensor suite

    Energy Technology Data Exchange (ETDEWEB)

    Ledebuhr, A.G. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    LLNL designed and built the suite of six miniaturized light-weight space-qualified sensors utilized in the Clementine mission. A major goal of the Clementine program was to demonstrate technologies originally developed for Ballistic Missile Defense Organization Programs. These sensors were modified to gather data from the moon. This overview presents each of these sensors and some preliminary on-orbit performance estimates. The basic subsystems of these sensors include optical baffles to reject off-axis stray light, light-weight ruggedized optical systems, filter wheel assemblies, radiation tolerant focal plane arrays, radiation hardened control and readout electronics and low mass and power mechanical cryogenic coolers for the infrared sensors. Descriptions of each sensor type are given along with design specifications, photographs and on-orbit data collected.

  2. Intelligent Sensors Security

    Directory of Open Access Journals (Sweden)

    Andrzej Bialas

    2010-01-01

    Full Text Available The paper is focused on the security issues of sensors provided with processors and software and used for high-risk applications. Common IT related threats may cause serious consequences for sensor system users. To improve their robustness, sensor systems should be developed in a restricted way that would provide them with assurance. One assurance creation methodology is Common Criteria (ISO/IEC 15408 used for IT products and systems. The paper begins with a primer on the Common Criteria, and then a general security model of the intelligent sensor as an IT product is discussed. The paper presents how the security problem of the intelligent sensor is defined and solved. The contribution of the paper is to provide Common Criteria (CC related security design patterns and to improve the effectiveness of the sensor development process.

  3. Autonomous Chemical Vapour Detection by Micro UAV

    Directory of Open Access Journals (Sweden)

    Kent Rosser

    2015-12-01

    Full Text Available The ability to remotely detect and map chemical vapour clouds in open air environments is a topic of significant interest to both defence and civilian communities. In this study, we integrate a prototype miniature colorimetric chemical sensor developed for methyl salicylate (MeS, as a model chemical vapour, into a micro unmanned aerial vehicle (UAV, and perform flights through a raised MeS vapour cloud. Our results show that that the system is capable of detecting MeS vapours at low ppm concentration in real-time flight and rapidly sending this information to users by on-board telemetry. Further, the results also indicate that the sensor is capable of distinguishing “clean” air from “dirty”, multiple times per flight, allowing us to look towards autonomous cloud mapping and source localization applications. Further development will focus on a broader range of integrated sensors, increased autonomy of detection and improved engineering of the system.

  4. Vehicle Based Vector Sensor

    Science.gov (United States)

    2015-09-28

    300001 1 of 16 VEHICLE-BASED VECTOR SENSOR STATEMENT OF GOVERNMENT INTEREST [0001] The invention described herein may be manufactured and...unmanned underwater vehicle that can function as an acoustic vector sensor . (2) Description of the Prior Art [0004] It is known that a propagating...mechanics. An acoustic vector sensor measures the particle motion via an accelerometer and combines Attorney Docket No. 300001 2 of 16 the

  5. Air Conditioning Overflow Sensor

    Science.gov (United States)

    1996-01-01

    The Technology Transfer Office at Stennis Space Center helped a local inventor develop a prototype of an attachment for central air conditioners and heat pumps that helps monitor water levels to prevent condensation overflow. The sensor will indicate a need for drain line maintenance and prevent possible damage caused by drain pan water spillover. An engineer in the Stennis Space Center prototype Development Laboratory used SSC sensor technology in the development of the sensor.

  6. Contact stress sensor

    Science.gov (United States)

    Kotovsky, Jack

    2012-02-07

    A contact stress sensor includes one or more MEMS fabricated sensor elements, where each sensor element of includes a thin non-recessed portion, a recessed portion and a pressure sensitive element adjacent to the recessed portion. An electric circuit is connected to the pressure sensitive element. The circuit includes a thermal compensator and a pressure signal circuit element configured to provide a signal upon movement of the pressure sensitive element.

  7. Transient multivariable sensor evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Vilim, Richard B.; Heifetz, Alexander

    2017-02-21

    A method and system for performing transient multivariable sensor evaluation. The method and system includes a computer system for identifying a model form, providing training measurement data, generating a basis vector, monitoring system data from sensor, loading the system data in a non-transient memory, performing an estimation to provide desired data and comparing the system data to the desired data and outputting an alarm for a defective sensor.

  8. Magnetic actuators and sensors

    CERN Document Server

    Brauer, John R

    2014-01-01

    An accessible, comprehensive guide on magnetic actuators and sensors, this fully updated second edition of Magnetic Actuators and Sensors includes the latest advances, numerous worked calculations, illustrations, and real-life applications. Covering magnetics, actuators, sensors, and systems, with updates of new technologies and techniques, this exemplary learning tool emphasizes computer-aided design techniques, especially magnetic finite element analysis, commonly used by today's engineers. Detailed calculations, numerous illustrations, and discussions of discrepancies make this text an inva

  9. Beam imaging sensor

    Energy Technology Data Exchange (ETDEWEB)

    McAninch, Michael D.; Root, Jeffrey J.

    2016-07-05

    The present invention relates generally to the field of sensors for beam imaging and, in particular, to a new and useful beam imaging sensor for use in determining, for example, the power density distribution of a beam including, but not limited to, an electron beam or an ion beam. In one embodiment, the beam imaging sensor of the present invention comprises, among other items, a circumferential slit that is either circular, elliptical or polygonal in nature.

  10. Contact stress sensor

    Science.gov (United States)

    Kotovsky, Jack

    2014-02-11

    A method for producing a contact stress sensor that includes one or more MEMS fabricated sensor elements, where each sensor element of includes a thin non-recessed portion, a recessed portion and a pressure sensitive element adjacent to the recessed portion. An electric circuit is connected to the pressure sensitive element. The circuit includes a pressure signal circuit element configured to provide a signal upon movement of the pressure sensitive element.

  11. Acondicionamiento de sensores capacitivos

    OpenAIRE

    Campos López, Pedro

    2010-01-01

    Los sensores son componentes de instrumentación cuyo objetivo principal es detectar una magnitud física del entorno y transforarla en una magnitud eléctrica. El posterior tratamiento de esta señal permite valorar la magnitud física en su unidad característica. Actualmente en el mercado se encuentra una gran variedad de sensores y la tendencia destaca su aumento año tras año. Un tipo de sensor es clasificado como sensor capacitivo, cuya característica eléctrica es el valor de...

  12. Biomedical Sensors and Instruments

    CERN Document Server

    Tagawa, Tatsuo

    2011-01-01

    The living body is a difficult object to measure: accurate measurements of physiological signals require sensors and instruments capable of high specificity and selectivity that do not interfere with the systems under study. As a result, detailed knowledge of sensor and instrument properties is required to be able to select the "best" sensor from one of the many designed to meet these challenges. From the underlying principles to practical applications, this updated edition of Biomedical Sensors and Instruments provides an easy-to-understand introduction to the various kinds of biome

  13. Microfabricated Formaldehyde Gas Sensors

    Directory of Open Access Journals (Sweden)

    Karen C. Cheung

    2009-11-01

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

  14. Electrochemical Sensors Based on Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Md. Aminur Rahman

    2009-03-01

    Full Text Available This review focuses on recent contributions in the development of the electrochemical sensors based on carbon nanotubes (CNTs. CNTs have unique mechanical and electronic properties, combined with chemical stability, and behave electrically as a metal or semiconductor, depending on their structure. For sensing applications, CNTs have many advantages such as small size with larger surface area, excellent electron transfer promoting ability when used as electrodes modifier in electrochemical reactions, and easy protein immobilization with retention of its activity for potential biosensors. CNTs play an important role in the performance of electrochemical biosensors, immunosensors, and DNA biosensors. Various methods have been developed for the design of sensors using CNTs in recent years. Herein we summarize the applications of CNTs in the construction of electrochemical sensors and biosensors along with other nanomaterials and conducting polymers.

  15. Diamond sensors for future high energy experiments

    Energy Technology Data Exchange (ETDEWEB)

    Bachmair, Felix, E-mail: bachmair@phys.ethz.ch

    2016-09-21

    With the planned upgrade of the LHC to High-Luminosity-LHC [1], the general purpose experiments ATLAS and CMS are planning to upgrade their innermost tracking layers with more radiation tolerant technologies. Chemical Vapor Deposition CVD diamond is one such technology. CVD diamond sensors are an established technology as beam condition monitors in the highest radiation areas of all LHC experiments. The RD42-collaboration at CERN is leading the effort to use CVD diamond as a material for tracking detectors operating in extreme radiation environments. An overview of the latest developments from RD42 is presented including the present status of diamond sensor production, a study of pulse height dependencies on incident particle flux and the development of 3D diamond sensors.

  16. Smart Sensor Network System For Environment Monitoring

    Directory of Open Access Journals (Sweden)

    Javed Ali Baloch

    2012-07-01

    Full Text Available SSN (Smart Sensor Network systems could be used to monitor buildings with modern infrastructure, plant sites with chemical pollution, horticulture, natural habitat, wastewater management and modern transport system. To sense attributes of phenomena and make decisions on the basis of the sensed value is the primary goal of such systems. In this paper a Smart Spatially aware sensor system is presented. A smart system, which could continuously monitor the network to observe the functionality and trigger, alerts to the base station if a change in the system occurs and provide feedback periodically, on demand or even continuously depending on the nature of the application. The results of the simulation trials presented in this paper exhibit the performance of a Smart Spatially Aware Sensor Networks.

  17. Development of SERS active fibre sensors

    CERN Document Server

    Polwart, E

    2002-01-01

    Surface-enhanced Raman scattering (SERS) is sensitive and selective and when coupled with fibre-optics could potentially produce an effective chemical sensing system. This thesis concerns the development of a single-fibre-based sensor, with an integral SERS-active substrate. A number of different methods for the manufacture of SERS-active surfaces on glass substrates were investigated and compared. The immobilisation of metal nanoparticles on glass functionalised with (3-aminopropyl)trimethoxysilane emerged as a suitable approach for the production of sensors. Substrates prepared by this approach were characterised using UV-visible spectroscopy, electron microscopy and Raman mapping. It was found that exposure of substrates to laser radiation led to a decrease in the signal recorded from adsorbed analytes. This speed of the decrease was shown to depend on the analyte, and the exciting wavelength and power. SERS-active fibre sensors were produced by immobilisation of silver nanoparticles at the distal end of a...

  18. Optical fibre cantilever sensor for biological application

    Science.gov (United States)

    Li, J.; Zhou, Y. X.; Patterson, G.; Shu, W. M.; Maier, R. R. J.; Fowler, R.; Hand, D. P.; MacPherson, W. N.

    2014-05-01

    Micro-cantilever sensors have shown great promise in a wide range of application are as including chemical and biological sensing. However, many of these devices are based upon a sensor `chip' that requires careful alignment between the cantilever and the read-out system, which can be challenging. Furthermore, optical interrogation typically involves a bulky free-space system. Optical fibre addressed cantilevers have been reported previously in the literature and in this paper we propose techniques to design and fabricate polymer micro-cantilevers for attachment onto the end of standard single mode fibres using laser machining. Low-cost optical sources and a fibre coupled spectrometer are employed to monitor the cantilever deflection and therefore observe biological binding between a species of interest and an activated cantilever. Proof-of-concept experiments show that the sensor is capable of detecting pathogen concentration with down to a level of 105cfu/ml.

  19. Diamond sensors for future high energy experiments

    Science.gov (United States)

    Bachmair, Felix

    2016-09-01

    With the planned upgrade of the LHC to High-Luminosity-LHC [1], the general purpose experiments ATLAS and CMS are planning to upgrade their innermost tracking layers with more radiation tolerant technologies. Chemical Vapor Deposition CVD diamond is one such technology. CVD diamond sensors are an established technology as beam condition monitors in the highest radiation areas of all LHC experiments. The RD42-collaboration at CERN is leading the effort to use CVD diamond as a material for tracking detectors operating in extreme radiation environments. An overview of the latest developments from RD42 is presented including the present status of diamond sensor production, a study of pulse height dependencies on incident particle flux and the development of 3D diamond sensors.

  20. LONG-TERM MONITORING SENSOR NETWORK

    Energy Technology Data Exchange (ETDEWEB)

    Stephen P. Farrington; John W. Haas; Neal Van Wyck

    2003-10-16

    Long-term monitoring (LTM) associated with subsurface contamination sites is a key element of Long Term Stewardship and Legacy Management across the Department of Energy (DOE) complex. However, both within the DOE and elsewhere, LTM is an expensive endeavor, often exceeding the costs of the remediation phase of a clean-up project. The primary contributors to LTM costs are associated with labor. Sample collection, storage, preparation, analysis, and reporting can add a significant financial burden to project expense when extended over many years. Development of unattended, in situ monitoring networks capable of providing quantitative data satisfactory to regulatory concerns has the potential to significantly reduce LTM costs. But survival and dependable operation in a difficult environment is a common obstacle to widespread use across the DOE complex or elsewhere. Deploying almost any sensor in the subsurface for extended periods of time will expose it to chemical and microbial degradation. Over the time-scales required for in situ LTM, even the most advanced sensor systems may be rendered useless. Frequent replacement or servicing (cleaning) of sensors is expensive and labor intensive, offsetting most, if not all, of the cost savings realized with unattended, in situ sensors. To enable facile, remote monitoring of contaminants and other subsurface parameters over prolonged periods, Applied Research Associates, Inc has been working to develop an advanced LTM sensor network consisting of three key elements: (1) an anti-fouling sensor chamber that can accommodate a variety of chemical and physical measurement devices based on electrochemical, optical and other techniques; (2) two rapid, cost effective, and gentle means of emplacing sensor packages either at precise locations directly in the subsurface or in pre-existing monitoring wells; and (3) a web browser-based data acquisition and control system (WebDACS) utilizing field-networked microprocessor-controlled smart

  1. Semantic Sensor Web

    Science.gov (United States)

    Sheth, A.; Henson, C.; Thirunarayan, K.

    2008-12-01

    Sensors are distributed across the globe leading to an avalanche of data about our environment. It is possible today to utilize networks of sensors to detect and identify a multitude of observations, from simple phenomena to complex events and situations. The lack of integration and communication between these networks, however, often isolates important data streams and intensifies the existing problem of too much data and not enough knowledge. With a view to addressing this problem, the Semantic Sensor Web (SSW) [1] proposes that sensor data be annotated with semantic metadata that will both increase interoperability and provide contextual information essential for situational knowledge. Kno.e.sis Center's approach to SSW is an evolutionary one. It adds semantic annotations to the existing standard sensor languages of the Sensor Web Enablement (SWE) defined by OGC. These annotations enhance primarily syntactic XML-based descriptions in OGC's SWE languages with microformats, and W3C's Semantic Web languages- RDF and OWL. In association with semantic annotation and semantic web capabilities including ontologies and rules, SSW supports interoperability, analysis and reasoning over heterogeneous multi-modal sensor data. In this presentation, we will also demonstrate a mashup with support for complex spatio-temporal-thematic queries [2] and semantic analysis that utilize semantic annotations, multiple ontologies and rules. It uses existing services (e.g., GoogleMap) and semantics enhanced SWE's Sensor Observation Service (SOS) over weather and road condition data from various sensors that are part of Ohio's transportation network. Our upcoming plans are to demonstrate end to end (heterogeneous sensor to application) semantics support and study scalability of SSW involving thousands of sensors to about a billion triples. Keywords: Semantic Sensor Web, Spatiotemporal thematic queries, Semantic Web Enablement, Sensor Observation Service [1] Amit Sheth, Cory Henson, Satya

  2. Detection of electrophilic and nucleophilic chemical agents

    Energy Technology Data Exchange (ETDEWEB)

    McElhanon, James R.; Shepodd, Timothy J.

    2014-08-12

    A "real time" method for detecting chemical agents generally and particularly electrophilic and nucleophilic species by employing tunable, precursor sensor materials that mimic the physiological interaction of these agents to form highly florescent berberine-type alkaloids that can be easily and rapidly detected. These novel precursor sensor materials can be tuned for reaction with both electrophilic (chemical species, toxins) and nucleophilic (proteins and other biological molecules) species. By bonding or otherwise attaching these precursor molecules to a surface or substrate they can be used in numerous applications.

  3. Mm-Wave Spectroscopic Sensors, Catalogs, and Uncatalogued Lines

    Science.gov (United States)

    Medvedev, Ivan; Neese, Christopher F.; De Lucia, Frank C.

    2014-06-01

    Analytical chemical sensing based on high resolution rotational molecular spectra has been recognized as a viable technique for decades. We recently demonstrated a compact implementation of such a sensor. Future generations of these sensors will rely on automated algorithms for quantification of chemical dilutions based on their spectral libraries, as well as identification of spectral features not present in spectral catalogs. Here we present an algorithm aimed at detection of unidentified lines in complex molecular species based on spectroscopic libraries developed in our previous projects. We will discuss the approaches suitable for data mining in feature-rich rotational molecular spectra. Neese, C.F., I.R. Medvedev, G.M. Plummer, A.J. Frank, C.D. Ball, and F.C. De Lucia, "A Compact Submillimeter/Terahertz Gas Sensor with Efficient Gas Collection, Preconcentration, and ppt Sensitivity." Sensors Journal, IEEE, 2012. 12(8): p. 2565-2574

  4. Integrated cantilever-based flow sensors with tunable sensitivity for in-line monitoring of flow fluctuations in microfluidic systems

    DEFF Research Database (Denmark)

    Noeth, Nadine-Nicole; Keller, Stephan Sylvest; Boisen, Anja

    2014-01-01

    For devices such as bio-/chemical sensors in microfluidic systems, flow fluctuations result in noise in the sensor output. Here, we demonstrate in-line monitoring of flow fluctuations with a cantilever-like sensor integrated in a microfluidic channel. The cantilevers are fabricated in different m...... pumps connected to the microfluidic system. © 2013 by the authors; licensee MDPI, Basel, Switzerland....

  5. Nanophotonic Image Sensors.

    Science.gov (United States)

    Chen, Qin; Hu, Xin; Wen, Long; Yu, Yan; Cumming, David R S

    2016-09-01

    The increasing miniaturization and resolution of image sensors bring challenges to conventional optical elements such as spectral filters and polarizers, the properties of which are determined mainly by the materials used, including dye polymers. Recent developments in spectral filtering and optical manipulating techniques based on nanophotonics have opened up the possibility of an alternative method to control light spectrally and spatially. By integrating these technologies into image sensors, it will become possible to achieve high compactness, improved process compatibility, robust stability and tunable functionality. In this Review, recent representative achievements on nanophotonic image sensors are presented and analyzed including image sensors with nanophotonic color filters and polarizers, metamaterial-based THz image sensors, filter-free nanowire image sensors and nanostructured-based multispectral image sensors. This novel combination of cutting edge photonics research and well-developed commercial products may not only lead to an important application of nanophotonics but also offer great potential for next generation image sensors beyond Moore's Law expectations.

  6. Steerable Capacitive Proximity Sensor

    Science.gov (United States)

    Jenstrom, Del T.; Mcconnell, Robert L.

    1994-01-01

    Steerable capacitive proximity sensor of "capaciflector" type based partly on sensing units described in GSC-13377 and GSC-13475. Position of maximum sensitivity adjusted without moving sensor. Voltage of each driven shield adjusted separately to concentrate sensing electric field more toward one side or other.

  7. Chalcogenide Fibre Displacement Sensor

    Science.gov (United States)

    2001-06-01

    Fibre optic technology offers the possibility for developing of a variety of physical sensors for a wide range of physical parameters. The main...integrating sphere. The use of chalcogenide rather quartz fibre optic highly increases the Sensitivity of the sensor. Experimental set-up, transmission characteristics and technical parameters are presented.

  8. Sensor Data Integrity

    Science.gov (United States)

    2008-12-01

    Alempijevic, S.R. Kodagoda, J.P. Underwood, S. Kumar, and G. Dissanayake. Mutual information based sensor registration and calibration. In Procedings of...Steven Scheding. Calibration of range sensor pose on mobile platforms. In Procedings of the 2007 IEEE/RSJ Int. Conf. on Intelligent Robots and Systems

  9. Potentiometric anion selective sensors

    NARCIS (Netherlands)

    Antonisse, Martijn M.G.; Reinhoudt, David N.

    1999-01-01

    In comparison with selective receptors (and sensors) for cationic species, work on the selective complexation and detection of anions is of more recent date. There are three important components for a sensor, a transducer element, a membrane material that separates the transducer element and the aqu

  10. Sensors in Education

    NARCIS (Netherlands)

    Van Rosmalen, Peter; Schneider, Jan; Börner, Dirk

    2014-01-01

    Sensors rapidly become available both for personal as well as scientific use. A wide range of applications exists for personal use e.g. safety in and around the house, sport, fitness and health. In this workshop we will explore how sensors are (can be) used in education. We start with an introducti

  11. Wireless Sensors Network (Sensornet)

    Science.gov (United States)

    Perotti, J.

    2003-01-01

    The Wireless Sensor Network System presented in this paper provides a flexible reconfigurable architecture that could be used in a broad range of applications. It also provides a sensor network with increased reliability; decreased maintainability costs, and assured data availability by autonomously and automatically reconfiguring to overcome communication interferences.

  12. Optical networks for wideband sensor array

    Science.gov (United States)

    Sheng, Lin Horng

    2011-12-01

    This thesis presents the realization of novel systems for optical sensing networks with an array of long-period grating (LPG) sensors. As a launching point of the thesis, the motivation to implement optical sensing network in precisely catering LPG sensors is presented. It highlights the flexibility of the sensing network to act as the foundation in order to boost the application of the various LPG sensor design in biological and chemical sensing. After the thorough study on the various optical sensing networks, sub-carrier multiplexing (SCM) and optical time division multiplexing (OTDM) schemes are adopted in conjunction with tunable laser source (TLS) to facilitate simultaneous interrogation of the LPG sensors array. In fact, these systems are distinct to have the capability to accommodate wideband optical sensors. Specifically, the LPG sensors which is in 20nm bandwidth are identified to operate in these systems. The working principles of the systems are comprehensively elucidated in this thesis. It highlights the mathematical approach to quantify the experimental setup of the optical sensing network. Additionally, the system components of the designs are identified and methodically characterized so that the components well operate in the designed environment. A mockup has been setup to demonstrate the application in sensing of various liquid indices and analyse the response of the LPG sensors in order to evaluate the performance of the systems. Eventually, the resemblance of the demultiplexed spectral response to the pristine spectral response are quantified to have excellent agreement. Finally, the promising result consistency of the systems is verified through repeatability test.

  13. Sensor Network Motes:

    DEFF Research Database (Denmark)

    Leopold, Martin

    This dissertation describes our efforts to improve sensor network performance evaluation and portability, within the context of the sensor network project Hogthrob. In Hogthrob, we faced the challenge of building an sensor network architecture for sow monitoring. This application has hard...... requirements on price and performance, and shows great potential for using sensor networks. Throughout the project we let the application requirements guide our design choices, leading us to push the technologies further to meet the specific goal of the application. In this dissertation, we attack two key...... to investigate these challenges and apart from developing the methodologies, we also present the results of our experiments. In particular, we present a new vector based methodology for performance evaluation of sensor network devices (motes) and applications, based on application specific benchmarking...

  14. Sensor Data Fusion

    DEFF Research Database (Denmark)

    Plascencia, Alfredo; Stepán, Petr

    2006-01-01

    The main contribution of this paper is to present a sensor fusion approach to scene environment mapping as part of a Sensor Data Fusion (SDF) architecture. This approach involves combined sonar array with stereo vision readings.  Sonar readings are interpreted using probability density functions...... to the occupied and empty regions. Scale Invariant Feature Transform (SIFT) feature descriptors are interpreted using gaussian probabilistic error models. The use of occupancy grids is proposed for representing the sensor readings. The Bayesian estimation approach is applied to update the sonar array......  and the SIFT descriptors' uncertainty grids. The sensor fusion yields a significant reduction in the uncertainty of the occupancy grid compared to the individual sensor readings....

  15. Magnetic Particle-Based Hybrid Platforms for Bioanalytical Sensors

    Directory of Open Access Journals (Sweden)

    Silvana Andreescu

    2009-04-01

    Full Text Available Biomagnetic nano and microparticles platforms have attracted considerable interest in the field of biological sensors due to their interesting physico-chemical properties, high specific surface area, good mechanical stability and opportunities for generating magneto-switchable devices. This review discusses recent advances in the development and characterization of active biomagnetic nanoassemblies, their interaction with biological molecules and their use in bioanalytical sensors.

  16. Volatile organic compound optical fiber sensors: a review

    OpenAIRE

    Arregui, Francisco J.; Candido Bariain; Matias, Ignacio R; Cesar Elosua

    2006-01-01

    Volatile organic compound (VOC) detection is a topic of growing interest with applications in diverse fields, ranging from environmental uses to the food or chemical industries. Optical fiber VOC sensors offering new and interesting properties which overcame some of the inconveniences found on traditional gas sensors appeared over two decades ago. Thanks to its minimum invasive nature and the advantages that optical fiber offers such as light weight, passive nature, low attenuation and the...

  17. Adaptive inferential sensors based on evolving fuzzy models.

    Science.gov (United States)

    Angelov, Plamen; Kordon, Arthur

    2010-04-01

    A new technique to the design and use of inferential sensors in the process industry is proposed in this paper, which is based on the recently introduced concept of evolving fuzzy models (EFMs). They address the challenge that the modern process industry faces today, namely, to develop such adaptive and self-calibrating online inferential sensors that reduce the maintenance costs while keeping the high precision and interpretability/transparency. The proposed new methodology makes possible inferential sensors to recalibrate automatically, which reduces significantly the life-cycle efforts for their maintenance. This is achieved by the adaptive and flexible open-structure EFM used. The novelty of this paper lies in the following: (1) the overall concept of inferential sensors with evolving and self-developing structure from the data streams; (2) the new methodology for online automatic selection of input variables that are most relevant for the prediction; (3) the technique to detect automatically a shift in the data pattern using the age of the clusters (and fuzzy rules); (4) the online standardization technique used by the learning procedure of the evolving model; and (5) the application of this innovative approach to several real-life industrial processes from the chemical industry (evolving inferential sensors, namely, eSensors, were used for predicting the chemical properties of different products in The Dow Chemical Company, Freeport, TX). It should be noted, however, that the methodology and conclusions of this paper are valid for the broader area of chemical and process industries in general. The results demonstrate that well-interpretable and with-simple-structure inferential sensors can automatically be designed from the data stream in real time, which predict various process variables of interest. The proposed approach can be used as a basis for the development of a new generation of adaptive and evolving inferential sensors that can address the

  18. Chemical intolerance

    DEFF Research Database (Denmark)

    Dantoft, Thomas Meinertz; Andersson, Linus; Nordin, Steven;

    2015-01-01

    Chemical intolerance (CI) is a term used to describe a condition in which the sufferer experiences a complex array of recurrent unspecific symptoms attributed to low-level chemical exposure that most people regard as unproblematic. Severe CI constitutes the distinguishing feature of multiple...... chemical sensitivity (MCS). The symptoms reported by CI subjects are manifold, involving symptoms from multiple organs systems. In severe cases of CI, the condition can cause considerable life-style limitations with severe social, occupational and economic consequences. As no diagnostic tools for CI...

  19. Hazardous Chemicals

    Centers for Disease Control (CDC) Podcasts

    2007-04-10

    Chemicals are a part of our daily lives, providing many products and modern conveniences. With more than three decades of experience, The Centers for Disease Control and Prevention (CDC) has been in the forefront of efforts to protect and assess people's exposure to environmental and hazardous chemicals. This report provides information about hazardous chemicals and useful tips on how to protect you and your family from harmful exposure.  Created: 4/10/2007 by CDC National Center for Environmental Health.   Date Released: 4/13/2007.

  20. A Novel Interdigital Capacitor Pressure Sensor Based on LTCC Technology

    Directory of Open Access Journals (Sweden)

    Qiulin Tan

    2014-01-01

    Full Text Available A novel passive wireless pressure sensor is proposed based on LTCC (low temperature cofired ceramic technology. The sensor employs a passive LC circuit, which is composed of a variable interdigital capacitor and a constant inductor. The inductor and capacitor were fabricated by screen-printing. Pressure measurement is tested using a wireless mutual inductance coupling method. The experimental sensitivity of the sensor is about 273.95 kHz/bar below 2 bar. Experimental results show that the sensor can be read out wirelessly by external antenna at 600°C. The max readout distance is 3 cm at room temperature. The sensors described can be applied for monitoring of gas pressure in harsh environments, such as environment with high temperature and chemical corrosion.