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Sample records for alcohol sensor based

  1. Free-standing gallium nitride membrane-based sensor for the impedimetric detection of alcohols

    NASA Astrophysics Data System (ADS)

    Alifragis, Y.; Roussos, G.; Pantazis, A. K.; Konstantinidis, G.; Chaniotakis, N.

    2016-02-01

    We report on the fabrication and characterization of single-crystal Gallium Nitride (GaN) membrane organic gas sensor. The sensing device is based on the highly stable free-standing III-nitride membrane, and it is probed using non-destructive impedance spectroscopy. Monitoring the effect of a series of polar organic molecules on the electrochemical impedance spectrum of the sensing membrane in the frequency range of 1 mHz to 0.1 MHz at room temperature, we concluded that the sensor is highly sensitive to alcohols, in the gas phase, with selectivity that depends on the molecular weight and vapor pressure of the molecules. The highly robust and stable GaN crystalline membrane and the ability to test these sensors using impedance spectroscopy and electrochemical probing techniques suggest that single crystal GaN-based sensors can find a wide range of applications in harsh and extreme environments.

  2. Highly sensitive alcohol sensor based on a single Er-doped In2O3 nanoribbon

    NASA Astrophysics Data System (ADS)

    Qin, Zhaojun; Liu, Yingkai; Chen, Weiwu; Ai, Peng; Wu, Yuemei; Li, Shuanghui; Yu, Dapeng

    2016-02-01

    Pure In2O3 NBs and Er-In2O3 NBs have been successfully synthesized by carbon thermal reduction. The doping of Er leads the optimal temperature of the In2O3 to decrease. The response of the Er-In2O3 sensor to 100 ppm of alcohol is 4.8 at 220 °C, which is twice larger than that of the pure In2O3 sensor. It is also found that the doping of Er has increased the performance of the sensors. Moreover, Er-In2O3 sensor has a fast response (recovery) time to different concentration of alcohol at 220 °C. In addition, the mechanism of pure In2O3 sensor and Er-In2O3 sensor are discussed.

  3. Alcohol vapor sensing by cadmium-doped zinc oxide thick films based chemical sensor

    NASA Astrophysics Data System (ADS)

    Zargar, R. A.; Arora, M.; Chackrabarti, S.; Ahmad, S.; Kumar, J.; Hafiz, A. K.

    2016-04-01

    Cadmium-doped zinc oxide nanoparticles were derived by simple chemical co-precipitation route using zinc acetate dihydrate and cadmium acetate dihydrate as precursor materials. The thick films were casted from chemical co-precipitation route prepared nanoparticles by economic facile screen printing method. The structural, morphological, optical and electrical properties of the film were characterized relevant to alcohol vapor sensing application by powder XRD, SEM, UV-VIS and DC conductivity techniques. The response and sensitivity of alcohol (ethanol) vapor sensor are obtained from the recovery curves at optimum working temperature range from 20∘C to 50∘C. The result shows that maximum sensitivity of the sensor is observed at 25∘C operating temperature. On varying alcohol vapor concentration, minor variation in resistance has been observed. The sensing mechanism of sensor has been described in terms of physical adsorption and chemical absorption of alcohol vapors on cadmium-doped zinc oxide film surface and inside film lattice network through weak hydrogen bonding, respectively.

  4. A novel method to quantify the activity of alcohol acetyltransferase Using a SnO2-based sensor of electronic nose.

    PubMed

    Hu, Zhongqiu; Li, Xiaojing; Wang, Huxuan; Niu, Chen; Yuan, Yahong; Yue, Tianli

    2016-07-15

    Alcohol acetyltransferase (AATFase) extensively catalyzes the reactions of alcohols to acetic esters in microorganisms and plants. In this work, a novel method has been proposed to quantify the activity of AATFase using a SnO2-based sensor of electronic nose, which was determined on the basis of its higher sensitivity to the reducing alcohol than the oxidizing ester. The maximum value of the first-derivative of the signals from the SnO2-based sensor was therein found to be an eigenvalue of isoamyl alcohol concentration. Quadratic polynomial regression perfectly fitted the correlation between the eigenvalue and the isoamyl alcohol concentration. The method was used to determine the AATFase activity in this type of reaction by calculating the conversion rate of isoamyl alcohol. The proposed method has been successfully applied to determine the AATFase activity of a cider yeast strain. Compared with GC-MS, the method shows promises with ideal recovery and low cost. PMID:26948643

  5. Development of polymer optical waveguide-type alcohol sensor

    NASA Astrophysics Data System (ADS)

    Nagata, Junichi; Honma, Satoshi; Morisawa, Masayuki; Muto, Shinzo

    2008-03-01

    Recently, alcohols such as methanol and ethanol have a wide attention as important fuel in next generation. However, As is known, many alcohols have a toxic and explosive nature. To prevent accidents caused by alcohol, development of a safety and highly sensitive sensor is required strongly. In addition, it is desired to be simple and low-cost. So, in this paper, polymer waveguide-type optical alcohol sensors such as fiber-type and channel waveguide-type have been studied. In these sensor head, refractive index n II of cladding layer was set at slightly larger value than that of core (n I). Therefore, in the state without alcohol, the sensor head operate as a leaky waveguide. On the other hand in the state with alcohol, cladding polymer causes swelling and its refractive index becomes lower than n I in core. Based on this principle, large change in output light intensity occurs and detection of alcohol concentration becomes possible even for vapor phase alcohol. In the experiment using a fiber-type sensor with a core size of 0.25 mm, detection of 1% methanol vapor could easily be obtained. Furthermore, using a channel waveguide-type sensor head with a core size of about 50μm×40μm, large increase in sensitivity was observed.

  6. A new selective fluorene-based fluorescent internal charge transfer (ICT) sensor for sugar alcohols in aqueous solution.

    PubMed

    Hosseinzadeh, Rahman; Mohadjerani, Maryam; Pooryousef, Mona

    2016-03-01

    Sugar alcohols, such as sorbitol, are commonly used as a replacement for sucrose in the food industry, applied as starting material for vitamin C synthesis, and involved as one of the causative factors in diabetic complications. Therefore, their detection and quantification in aqueous solution are necessary. The reversible covalent interactions between boronic acids and diols are the basis of efficient methods for the detection of saccharides. Herein, we report a new internal charge transfer (ICT) fluorene-based fluorescent boronic acid sensor (1) 2-[(9,9-dimethyl-9H-fluoren-2-yl-amino)methyl] phenyl boronic acid that shows significant fluorescence changes upon addition of saccharides. The boronic acid has high affinity (K a = 1107.9 M(-1)) and selectivity for sorbitol at pH = 8.31. It showed a linear response toward sorbitol in the concentration range from 1.0 × 10(-5) to 6.0 × 10(-4) mol L(-1) with the detection limit of 7.04 × 10(-6) mol L(-1). Sensor 1 was used to detect sorbitol in real samples with good recovery. PMID:26758597

  7. Photonic crystal fiber interferometric pH sensor based on polyvinyl alcohol/polyacrylic acid hydrogel coating.

    PubMed

    Hu, Pengbing; Dong, Xinyong; Wong, Wei Chang; Chen, Li Han; Ni, Kai; Chan, Chi Chiu

    2015-04-01

    We present a simple photonic crystal fiber interferometer (PCFI) that operates in reflection mode for pH measurement. The sensor is made by coating polyvinyl alcohol/polyacrylic acid (PVA/PAA) hydrogel onto the surface of the PCFI, constructed by splicing a stub of PCF at the distal end of a single-mode fiber with its free end airhole collapsed. The experimental results demonstrate a high average sensitivity of 0.9 nm/pH unit for the 11 wt.% PVA/PAA coated sensor in the pH range from 2.5 to 6.5. The sensor also displays high repeatability and stability and low cross-sensitivity to temperature. Fast, reversible rise and fall times of 12 s and 18 s, respectively, are achieved for the sensor time response. PMID:25967171

  8. Predictors of Detection of Alcohol Use Episodes Using a Transdermal Alcohol Sensor

    PubMed Central

    Barnett, Nancy P.; Meade, E.B.; Glynn, Tiffany R.

    2014-01-01

    The objective of this investigation was to establish the ability of the Secure Continuous Remote Alcohol Monitoring (SCRAM) alcohol sensor to detect different levels of self-reported alcohol consumption, and to determine whether gender and body mass index, alcohol dependence, bracelet version, and age of bracelet influenced detection of alcohol use. Method Heavy drinking adults (N = 66; 46% female) wore the SCRAM for 1–28 days and reported their alcohol use in daily web-based surveys. Participant reports of alcohol use were matched with drinking episodes identified from bracelet readings. Results On days when bracelets were functional, 690 drinking episodes were reported and 502 of those episodes (72.8%) were detected using sensor data. Using Generalized Estimating Equations, we found no gender differences in detection of reported drinking episodes (77% for women, 69% for men). In univariate analyses, at the level of fewer than five drinks, women’s episodes were more likely to be detected, likely due to the significantly higher TAC levels of these episodes, whereas at the level of five or more drinks, there was no gender difference in detection (92.6% for women, 93.4% of men’s). In multivariable analyses, no variables other than number of drinks significantly predicted alcohol detection. Conclusion The SCRAM sensor is very good at detecting five or more drinks; performance of the monitor below this level was better among women due to their higher TAC levels. Individual person characteristics and bracelet features were not related to detection after number of drinks was included. Minimal bracelet malfunctions were noted. PMID:24490713

  9. Design and fabrication of optical chemical sensor for detection of nitroaromatic explosives based on fluorescence quenching of phenol red immobilized poly(vinyl alcohol) membrane.

    PubMed

    Zarei, Ali Reza; Ghazanchayi, Behnam

    2016-04-01

    The present study developed a new optical chemical sensor for detection of nitroaromatic explosives in liquid phase. The method is based on the fluorescence quenching of phenol red as fluorophore in a poly(vinyl alcohol) (PVA) membrane in the presence of nitroaromatic explosives as quenchers, e.g., 2,4,6-trinitrotoluene (TNT), 2,4-dinitrotoluene (2,4-DNT), 4-nitrotoluene (4-NT), 2,4,6-trinitrobenzene (TNB), and nitrobenzene (NB). For chemical immobilization of phenol red in PVA, phenol red reacted with formaldehyde to produce hydroxymethyl groups and then attached to PVA membrane through the hydroxymethyl groups. The optical sensor showed strong quenching of nitroaromatic explosives. A Stern-Volmer graph for each explosive was constructed and showed that the range of concentration from 5.0 × 10(-6) to 2.5 × 10(-4) mol L(-1) was linear for each explosive and sensitivity varied as TNB >TNT>2,4-DNT>NB>4-NT. The response time of the sensor was within 1 min. The proposed sensor showed good reversibility and reproducibility. PMID:26838395

  10. A novel nonenzymatic amperometric hydrogen peroxide sensor based on CuO@Cu2O nanowires embedded into poly(vinyl alcohol).

    PubMed

    Chirizzi, Daniela; Guascito, Maria Rachele; Filippo, Emanuela; Tepore, Antonio

    2016-01-15

    A new, very simple, rapid and inexpensive nonenzymatic amperometric sensor for hydrogen peroxide (H2O2) detection is proposed. It is based on the immobilization of cupric/cuprous oxide core shell nanowires (CuO@Cu2O-NWs) in a poly(vinyl alcohol) (PVA) matrix directly drop casted on a glassy carbon electrode surface to make a CuO@Cu2O core shell like NWs PVA embedded (CuO@Cu2O-NWs/PVA) sensor. CuO nanowires with mean diameters of 120-170nm and length in the range 2-5μm were grown by a simple catalyst-free thermal oxidation process based on resistive heating of pure copper wires at ambient conditions. The oxidation process of the copper wire surface led to the formation of a three layered structure: a thick Cu2O bottom layer, a CuO thin intermediate layer and CuO nanowires. CuO nanowires were carefully scratched from Cu2O layer with a sharp knife, dispersed into ethanol and sonicated. Then, the NWs were embedded in PVA matrix. The morphological and spectroscopic characterization of synthesized CuO-NWs and CuO@Cu2O-NWs/PVA were performed by transmission electron microscopy (TEM), selected area diffraction pattern (SAD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analysis. Moreover a complete electrochemical characterization of these new CuO@Cu2O-NWs/PVA modified glassy carbon electrodes was performed by Cyclic Voltammetry (CV) and Cronoamperometry (CA) in phosphate buffer (pH=7; I=0.2) to investigate the sensing properties of this material against H2O2. The electrochemical performances of proposed sensors as high sensitivity, fast response, reproducibility and selectivity make them suitable for the quantitative determination of hydrogen peroxide substrate in batch analysis. PMID:26592586

  11. Design and modeling of quartz crystal microbalance-based ion sensors and aging of cryotropically gelled poly (vinyl alcohol)

    NASA Astrophysics Data System (ADS)

    Howie, Douglas W., Jr.

    Potential uses for hydrogels span the full range of science, technology, and medicine. In this work two different hydrogel matrices were studied in the context of ion sensing and drug transport. In chapter one the fundamentals of sensing using a shear-mode acoustic device are described. In chapters two and three the experimental and theoretical work to understand sensor behavior are described. Chapter four treats the diffusion of a model drug through aged, physically gelled PVOH. In chapter five the change of gel structure with time is investigated and the relationship between aging and gel preparation is discussed.

  12. NEUROBIOLOGICAL BASES OF ALCOHOL ADDICTION.

    PubMed

    Matošić, Ana; Marušić, Srđan; Vidrih, Branka; Kovak-Mufić, Ana; Cicin-Šain, Lipa

    2016-03-01

    Alcohol addiction is a heterogeneous psychiatric disorder according to both phenotype and etiology. Difference in phenotype characteristics manifests in the manner the addiction arises, history of the alcoholic and history of drinking, comorbid disorders, and the phenomenon of abstinence difficulties. Concerning the etiology of alcoholism, the disease itself is considered to be a consequence of an interactive influence of the environment and genetic factors. Numerous researches conducted in the last decades discovered many aspects of the biochemical, cell and molecular bases of alcohol addiction, leading to a conclusion that alcoholism is, like many other addictions, a brain disease. By recognizing alcoholism as a disease which basically implies changes of the neurobiological mechanisms, as well as a clear genetic basis, it was supposed that the disease, having its basis solely in the symptomatology, is essentially heterogeneous. By trying to solve the problem of a clinically heterogeneous nature of the disease during the last fifty years, various sub-classifications of such patients have been suggested. According to Cloninger, subtypes of alcoholism differ also according to changes in the brain neurotransmission systems, i.e. it is supposed that patients suffering from alcoholism type 1 have a more pronounced dopaminergic transmission deficit, while dopaminergic transmission is not disturbed significantly in patients diagnosed with alcoholism type 2, who, however, have a significant lack of serotonergic transmission. In such a way, Cloninger actually presented the basis of the so-called neurobiological alcoholism model. Since he has connected differences in neurotransmission with differences in personality characteristics, this model is also known as the psychobiological model of alcoholism. The characteristic of alcoholism type 1 is avoiding damage (Harm Avoidance, HA) decreased dopamine transmission and increased serotonin transmission, while the significant

  13. UV-Assisted Alcohol Sensors using Gallium Nitride Nanowires Functionalized with Zinc Oxide and Tin Dioxide Nanoparticles

    NASA Astrophysics Data System (ADS)

    Bajpai, Ritu

    The motivation behind this work has been to address two of the most challenging issues posed to semiconductor gas sensors--- tuning the device selectivity and sensitivity to a wide variety of gases. In a chemiresistor type nanowire sensor, the sensitivity and selectivity depend on the interaction of different chemical analytes with the nanowire surface. Constrained by the surface properties of the nanowire material, most nanowire sensors can detect only specific type of analytes. In order to make a nano-sensor array for a wide range of analytes, there is a need to tune the device sensitivity and selectivity towards different chemicals. Employing the inherent advantages of nanostructure based sensing such as large surface area, miniature size, low power consumption, and nmol/mol (ppb) sensitivity, an attempt has been made to propose a device with tunable selectivity and sensitivity. The idea proposed in this work is to functionalize GaN nanowires which have relatively inactive surface properties (i.e., with no chemiresistive sensitivity to different classes of organic vapors), with analyte dependent active metal oxides. The selectivity of the sensor devices is controlled independent of the surface properties of the nanowire itself. It is the surface properties of the functionalizing metal oxides which determine the selectivity of these sensors. Further facilitated by the proposed fabrication technique, these sensors can be easily tuned to detect different gases. The prototype developed in this work is that of a UV assisted alcohol sensor using GaN nanowires functionalized with ZnO and SnO2 nanoparticles. As opposed to the widely demonstrated metal oxide based sensors assisted by elevated temperature, the operation of photoconductive semiconductor sensor devices such as those fabricated in this work, can also be assisted by UV illumination at room temperature. Temperature assisted sensing requires an integrated on-chip heater, which could impose constraints on the

  14. Supramolecular Based Membrane Sensors

    PubMed Central

    Ganjali, Mohammad Reza; Norouzi, Parviz; Rezapour, Morteza; Faridbod, Farnoush; Pourjavid, Mohammad Reza

    2006-01-01

    Supramolecular chemistry can be defined as a field of chemistry, which studies the complex multi-molecular species formed from molecular components that have relatively simpler structures. This field has been subject to extensive research over the past four decades. This review discusses classification of supramolecules and their application in design and construction of ion selective sensors.

  15. Graphene based multifunctional flame sensor.

    PubMed

    Ferry, Darim B; Pavan Kumar, R; Reddy, Siva K; Mukherjee, Anwesha; Misra, Abha

    2015-05-15

    Recently, graphene has attracted much attention due to its unique electrical and thermal properties along with its high surface area, and hence presents an ideal sensing material. We report a novel configuration of a graphene based flame sensor by exploiting the response of few layer graphene to a flame along two different directions, where flame detection results from a difference in heat transfer mechanisms. A complete sensor module was developed with a signal conditioning circuit that compensates for any drift in the baseline of the sensor, along with a flame detection algorithm implemented in a microcontroller to detect the flame. A pre-defined threshold for either of the sensors is tunable, which can be varied based on the nature of the flame, hence presenting a system that can be used for detection of any kind of flame. This finding also presents a scalable method that opens avenues to modify complicated sensing schemes. PMID:25900408

  16. Graphene based multifunctional flame sensor

    NASA Astrophysics Data System (ADS)

    Ferry, Darim B.; Pavan Kumar, R.; Reddy, Siva K.; Mukherjee, Anwesha; Misra, Abha

    2015-05-01

    Recently, graphene has attracted much attention due to its unique electrical and thermal properties along with its high surface area, and hence presents an ideal sensing material. We report a novel configuration of a graphene based flame sensor by exploiting the response of few layer graphene to a flame along two different directions, where flame detection results from a difference in heat transfer mechanisms. A complete sensor module was developed with a signal conditioning circuit that compensates for any drift in the baseline of the sensor, along with a flame detection algorithm implemented in a microcontroller to detect the flame. A pre-defined threshold for either of the sensors is tunable, which can be varied based on the nature of the flame, hence presenting a system that can be used for detection of any kind of flame. This finding also presents a scalable method that opens avenues to modify complicated sensing schemes.

  17. A wearable biochemical sensor for monitoring alcohol consumption lifestyle through Ethyl glucuronide (EtG) detection in human sweat.

    PubMed

    Selvam, Anjan Panneer; Muthukumar, Sriram; Kamakoti, Vikramshankar; Prasad, Shalini

    2016-01-01

    We demonstrate for the first time a wearable biochemical sensor for monitoring alcohol consumption through the detection and quantification of a metabolite of ethanol, ethyl glucuronide (EtG). We designed and fabricated two co-planar sensors with gold and zinc oxide as sensing electrodes. We also designed a LED based reporting for the presence of EtG in the human sweat samples. The sensor functions on affinity based immunoassay principles whereby monoclonal antibodies for EtG were immobilized on the electrodes using thiol based chemistry. Detection of EtG from human sweat was achieved through chemiresistive sensing mechanism. In this method, an AC voltage was applied across the two coplanar electrodes and the impedance across the sensor electrodes was measured and calibrated for physiologically relevant doses of EtG in human sweat. EtG detection over a dose concentration of 0.001-100 μg/L was demonstrated on both glass and polyimide substrates. Detection sensitivity was lower at 1 μg/L with gold electrodes as compared to ZnO, which had detection sensitivity of 0.001 μg/L. Based on the detection range the wearable sensor has the ability to detect alcohol consumption of up to 11 standard drinks in the US over a period of 4 to 9 hours. PMID:26996103

  18. A wearable biochemical sensor for monitoring alcohol consumption lifestyle through Ethyl glucuronide (EtG) detection in human sweat

    PubMed Central

    Panneer Selvam, Anjan; Muthukumar, Sriram; Kamakoti, Vikramshankar; Prasad, Shalini

    2016-01-01

    We demonstrate for the first time a wearable biochemical sensor for monitoring alcohol consumption through the detection and quantification of a metabolite of ethanol, ethyl glucuronide (EtG). We designed and fabricated two co-planar sensors with gold and zinc oxide as sensing electrodes. We also designed a LED based reporting for the presence of EtG in the human sweat samples. The sensor functions on affinity based immunoassay principles whereby monoclonal antibodies for EtG were immobilized on the electrodes using thiol based chemistry. Detection of EtG from human sweat was achieved through chemiresistive sensing mechanism. In this method, an AC voltage was applied across the two coplanar electrodes and the impedance across the sensor electrodes was measured and calibrated for physiologically relevant doses of EtG in human sweat. EtG detection over a dose concentration of 0.001–100 μg/L was demonstrated on both glass and polyimide substrates. Detection sensitivity was lower at 1 μg/L with gold electrodes as compared to ZnO, which had detection sensitivity of 0.001 μg/L. Based on the detection range the wearable sensor has the ability to detect alcohol consumption of up to 11 standard drinks in the US over a period of 4 to 9 hours. PMID:26996103

  19. Graphene Based Flexible Gas Sensors

    NASA Astrophysics Data System (ADS)

    Yi, Congwen

    Graphene is a novel carbon material with great promise for a range of applications due to its electronic and mechanical properties. Its two-dimensional nature translates to a high sensitivity to surface chemical interactions thereby making it an ideal platform for sensors. Graphene's electronic properties are not degraded due to mechanical flexing or strain (Kim, K. S., et al. nature 07719, 2009) offering another advantage for flexible sensors integrated into numerous systems including fabrics, etc. We have demonstrated a graphene NO2 sensor on a solid substrate (100nm SiO2/heavily doped silicon). Three different methods were used to synthesize graphene and the sensor fabrication process was optimized accordingly. Water is used as a controllable p-type dopant in graphene to study the relationship between doping and graphene's response to NO2 . Experimental results show that interface water between graphene and the supporting SiO2 substrate induces higher p-doping in graphene, leading to a higher sensitivity to NO2, consistent with theoretical predications (Zhang, Y. et al., Nanotechnology 20(2009) 185504). We have also demonstrated a flexible and stretchable graphene-based sensor. Few layer graphene, grown on a Ni substrate, is etched and transferred to a highly stretchable polymer substrate (VHB from 3M) with preloaded stress, followed by metal contact formation to construct a flexible, stretchable sensor. With up to 500% deformation caused by compressive stress, graphene still shows stable electrical response to NO2. Our results suggest that higher compressive stress results in smaller sheet resistance and higher sensitivity to NO2. A possible molecular detection sensor utilizing Surface Enhanced Raman Spectrum (SERS) based on a graphene/gallium nanoparticles platform is also studied. By correlating the enhancement of the graphene Raman modes with metal coverage, we propose that the Ga transfers electrons to the graphene creating local regions of enhanced

  20. Sensor for measuring alcohol content of alcohol/gasoline fuel mixtures

    SciTech Connect

    Harris, S.J.; Swarin, S.J.; Sultan, M.F.; Lambert, D.K.; Jack, M.D.

    1993-08-31

    A sensing device is described for determining the alcohol content of an alcohol/gasoline mixture comprising: a light source emitting a light beam containing at least a first and a second wavelengths within the near-infrared spectrum, said light beam being transmitted through the alcohol/gasoline fuel mixture; means for switching the current through said light source between at least two fixed values, so as to correspondingly switch the light intensity at said first and second wavelengths which is emitted by said light source; first and second detectors which are disposed so as to receive said emitted light beam after its transmission through the alcohol/gasoline fuel mixture, said first detector determines a first amount of absorption by the alcohol/gasoline fuel mixture at said first wavelength for each of said fixed values of current, and said second detector determines a second amount of absorption by the alcohol/gasoline fuel mixture at said second wavelength for each of said fixed values of current; means for separately measuring the output voltage from said first and second detectors for each of said power settings; and computational means for determining, from said output voltages, the ratio of said first and second absorbances by the alcohol/gasoline fuel mixture at said first and said second wavelengths for each of said fixed values of current such that said ratio of absorbances provide an output indicative of the alcohol content within the alcohol/gasoline mixture.

  1. Ionophore-Based Optical Sensors

    NASA Astrophysics Data System (ADS)

    Mistlberger, Günter; Crespo, Gastón A.; Bakker, Eric

    2014-06-01

    This review provides an overview of the key aspects of designing ionophore-based optical sensors (IBOS). Exact response functions are developed and compared with a simplified, generalized equation. We also provide a brief introduction into less established but promising working principles, namely dynamic response and exhaustive exchange. Absorbance and fluorescence are the main optical readout strategies used in the evaluation of a sensor response, but they usually require a robust referencing technique for real-world applications. Established referencing schemes using IBOS as well as those from other optical sensors are also discussed. Finally, the power of recently developed photoresponsive ion extraction/release systems is outlined and discussed in view of dynamically switchable IBOS or regenerative exhaustive exchange IBOS.

  2. Polymer based tunneling sensor

    NASA Technical Reports Server (NTRS)

    Cui, Tianhong (Inventor); Wang, Jing (Inventor); Zhao, Yongjun (Inventor)

    2006-01-01

    A process for fabricating a polymer based circuit by the following steps. A mold of a design is formed through a lithography process. The design is transferred to a polymer substrate through a hot embossing process. A metal layer is then deposited over at least part of said design and at least one electrical lead is connected to said metal layer.

  3. EDITORIAL: Sensors based on interfaces

    NASA Astrophysics Data System (ADS)

    Camassel, Jean; Soukiassian, Patrick G.

    2007-12-01

    of Physics D: Applied Physics describe some recent advances in this field and the very different approaches and/or techniques that can be used for the sensors' implementation. They include the use of molecularly modified metal nanoparticles in or as chemical sensors, especially for high sensitivity hydrogen sensors. Hydrogen sensing can also be achieved by performing galvanic measurements on a thin layer of perovskite oxide covered with platinum. In this case, one mixes an ionic (proton) transport in the oxide with an electronic one in the metal. Another focus is on optical and electrical read-out techniques, like surface-plasmon resonance (SPR), such as for immuno-sensor applications or piezo-electrical and electro-chemical detection. Toward this end, the preparation, structure and application of functional interfacial surfaces are described and discussed. A totally different approach based on the use of Hall effect measurements performed on a granular metal-oxide-semiconductor layer and different experimental solutions is also presented. Finally, optical sensors are addressed through the photonic modulation of surface properties or transmission interferometric absorption sensors. Mixed electrical and optical chemical sensors are also examined.

  4. Fluorographene based Ultrasensitive Ammonia Sensor

    PubMed Central

    Tadi, Kiran Kumar; Pal, Shubhadeep; Narayanan, Tharangattu N.

    2016-01-01

    Single molecule detection using graphene can be brought by tuning the interactions via specific dopants. Electrostatic interaction between the most electronegative element fluorine (F) and hydrogen (H) is one of the strong interactions in hydrogen bonding, and here we report the selective binding of ammonia/ammonium with F in fluorographene (FG) resulting to a change in the impedance of the system. Very low limit of detection value of ~0.44 pM with linearity over wide range of concentrations (1 pM–0.1 μM) is achieved using the FG based impedance sensor, andthisscreen printed FG sensor works in both ionized (ammonium) and un-ionized ammonia sensing platforms. The interaction energies of FG and NH3/NH4+ are evaluated using density functional theory calculations and the interactions are mapped. Here FGs with two different amounts of fluorinecontents −~5 atomic% (C39H16F2) and ~24 atomic% (C39H16F12) - are theoretically and experimentally studied for selective, high sensitive and ultra-low level detection of ammonia. Fast responding, high sensitive, large area patternable FG based sensor platform demonstrated here can open new avenues for the development of point-of-care devices and clinical sensors. PMID:27142522

  5. Fluorographene based Ultrasensitive Ammonia Sensor

    NASA Astrophysics Data System (ADS)

    Tadi, Kiran Kumar; Pal, Shubhadeep; Narayanan, Tharangattu N.

    2016-05-01

    Single molecule detection using graphene can be brought by tuning the interactions via specific dopants. Electrostatic interaction between the most electronegative element fluorine (F) and hydrogen (H) is one of the strong interactions in hydrogen bonding, and here we report the selective binding of ammonia/ammonium with F in fluorographene (FG) resulting to a change in the impedance of the system. Very low limit of detection value of ~0.44 pM with linearity over wide range of concentrations (1 pM–0.1 μM) is achieved using the FG based impedance sensor, andthisscreen printed FG sensor works in both ionized (ammonium) and un-ionized ammonia sensing platforms. The interaction energies of FG and NH3/NH4+ are evaluated using density functional theory calculations and the interactions are mapped. Here FGs with two different amounts of fluorinecontents ‑~5 atomic% (C39H16F2) and ~24 atomic% (C39H16F12) - are theoretically and experimentally studied for selective, high sensitive and ultra-low level detection of ammonia. Fast responding, high sensitive, large area patternable FG based sensor platform demonstrated here can open new avenues for the development of point-of-care devices and clinical sensors.

  6. Fluorographene based Ultrasensitive Ammonia Sensor.

    PubMed

    Tadi, Kiran Kumar; Pal, Shubhadeep; Narayanan, Tharangattu N

    2016-01-01

    Single molecule detection using graphene can be brought by tuning the interactions via specific dopants. Electrostatic interaction between the most electronegative element fluorine (F) and hydrogen (H) is one of the strong interactions in hydrogen bonding, and here we report the selective binding of ammonia/ammonium with F in fluorographene (FG) resulting to a change in the impedance of the system. Very low limit of detection value of ~0.44 pM with linearity over wide range of concentrations (1 pM-0.1 μM) is achieved using the FG based impedance sensor, andthisscreen printed FG sensor works in both ionized (ammonium) and un-ionized ammonia sensing platforms. The interaction energies of FG and NH3/NH4(+) are evaluated using density functional theory calculations and the interactions are mapped. Here FGs with two different amounts of fluorinecontents -~5 atomic% (C39H16F2) and ~24 atomic% (C39H16F12) - are theoretically and experimentally studied for selective, high sensitive and ultra-low level detection of ammonia. Fast responding, high sensitive, large area patternable FG based sensor platform demonstrated here can open new avenues for the development of point-of-care devices and clinical sensors. PMID:27142522

  7. Reputation-Based Secure Sensor Localization in Wireless Sensor Networks

    PubMed Central

    He, Jingsha; Xu, Jing; Zhu, Xingye; Zhang, Yuqiang; Zhang, Ting; Fu, Wanqing

    2014-01-01

    Location information of sensor nodes in wireless sensor networks (WSNs) is very important, for it makes information that is collected and reported by the sensor nodes spatially meaningful for applications. Since most current sensor localization schemes rely on location information that is provided by beacon nodes for the regular sensor nodes to locate themselves, the accuracy of localization depends on the accuracy of location information from the beacon nodes. Therefore, the security and reliability of the beacon nodes become critical in the localization of regular sensor nodes. In this paper, we propose a reputation-based security scheme for sensor localization to improve the security and the accuracy of sensor localization in hostile or untrusted environments. In our proposed scheme, the reputation of each beacon node is evaluated based on a reputation evaluation model so that regular sensor nodes can get credible location information from highly reputable beacon nodes to accomplish localization. We also perform a set of simulation experiments to demonstrate the effectiveness of the proposed reputation-based security scheme. And our simulation results show that the proposed security scheme can enhance the security and, hence, improve the accuracy of sensor localization in hostile or untrusted environments. PMID:24982940

  8. Carbon Nanotube Based Light Sensor

    NASA Technical Reports Server (NTRS)

    Wincheski, russell A. (Inventor); Smits, Jan M. (Inventor); Jordan, Jeffrey D. (Inventor); Watkins, Anthony Neal (Inventor); Ingram, JoAnne L. (Inventor)

    2006-01-01

    A light sensor substrate comprises a base made from a semi-conductive material and topped with a layer of an electrically non-conductive material. A first electrode and a plurality of carbon nanotube (CNT)-based conductors are positioned on the layer of electrically non-conductive material with the CNT-based conductors being distributed in a spaced apart fashion about a periphery of the first electrode. Each CNT-based conductor is coupled on one end thereof to the first electrode and extends away from the first electrode to terminate at a second free end. A second or gate electrode is positioned on the non-conductive material layer and is spaced apart from the second free end of each CNT-based conductor. Coupled to the first and second electrode is a device for detecting electron transfer along the CNT-based conductors resulting from light impinging on the CNT-based conductors.

  9. Image-based occupancy sensor

    SciTech Connect

    Polese, Luigi Gentile; Brackney, Larry

    2015-05-19

    An image-based occupancy sensor includes a motion detection module that receives and processes an image signal to generate a motion detection signal, a people detection module that receives the image signal and processes the image signal to generate a people detection signal, a face detection module that receives the image signal and processes the image signal to generate a face detection signal, and a sensor integration module that receives the motion detection signal from the motion detection module, receives the people detection signal from the people detection module, receives the face detection signal from the face detection module, and generates an occupancy signal using the motion detection signal, the people detection signal, and the face detection signal, with the occupancy signal indicating vacancy or occupancy, with an occupancy indication specifying that one or more people are detected within the monitored volume.

  10. Alcohol

    MedlinePlus

    ... How Can I Help a Friend Who Cuts? Alcohol KidsHealth > For Teens > Alcohol Print A A A ... you can make an educated choice. What Is Alcohol? Alcohol is created when grains, fruits, or vegetables ...

  11. Force-compensated hydrogel-based pH sensor

    NASA Astrophysics Data System (ADS)

    Deng, Kangfa; Gerlach, Gerald; Guenther, Margarita

    2015-04-01

    This paper presents the design, simulation, assembly and testing of a force-compensated hydrogel-based pH sensor. In the conventional deflection method, a piezoresistive pressure sensor is used as a chemical-mechanical-electronic transducer to measure the volume change of a pH-sensitive hydrogel. In this compensation method, the pH-sensitive hydrogel keeps its volume constant during the whole measuring process, independent of applied pH value. In order to maintain a balanced state, an additional thermal actuator is integrated into the close-loop sensor system with higher precision and faster dynamic response. Poly (N-isopropylacrylamide) (PNIPAAm) with 5 mol% monomer 3-acrylamido propionic acid (AAmPA) is used as the temperature-sensitive hydrogel, while poly (vinyl alcohol) with poly (acrylic acid) (PAA) serves as the pH-sensitive hydrogel. A thermal simulation is introduced to assess the temperature distribution of the whole microsystem, especially the temperature influence on both hydrogels. Following tests are detailed to verify the working functions of a sensor based on pH-sensitive hydrogel and an actuator based on temperature-sensitive hydrogel. A miniaturized prototype is assembled and investigated in deionized water: the response time amounts to about 25 min, just half of that one of a sensor based on the conventional deflection method. The results confirm the applicability of t he compensation method to the hydrogel-based sensors.

  12. Indium oxide based fiber optic SPR sensor

    NASA Astrophysics Data System (ADS)

    Shukla, Sarika; Sharma, Navneet K.

    2016-05-01

    Surface plasmon resonance based fiber optic sensor using indium oxide layer is presented and theoretically studied. It has been found that with increase in thickness of indium oxide layer beyond 170 nm, the sensitivity of SPR sensor decreases. 170 nm thick indium oxide layer based SPR sensor holds maximum sensitivity.

  13. UV-Assisted Alcohol Sensors using Gallium Nitride Nanowires Functionalized with Zinc Oxide and Tin Dioxide Nanoparticles

    NASA Astrophysics Data System (ADS)

    Bajpai, Ritu

    The motivation behind this work has been to address two of the most challenging issues posed to semiconductor gas sensors--- tuning the device selectivity and sensitivity to a wide variety of gases. In a chemiresistor type nanowire sensor, the sensitivity and selectivity depend on the interaction of different chemical analytes with the nanowire surface. Constrained by the surface properties of the nanowire material, most nanowire sensors can detect only specific type of analytes. In order to make a nano-sensor array for a wide range of analytes, there is a need to tune the device sensitivity and selectivity towards different chemicals. Employing the inherent advantages of nanostructure based sensing such as large surface area, miniature size, low power consumption, and nmol/mol (ppb) sensitivity, an attempt has been made to propose a device with tunable selectivity and sensitivity. The idea proposed in this work is to functionalize GaN nanowires which have relatively inactive surface properties (i.e., with no chemiresistive sensitivity to different classes of organic vapors), with analyte dependent active metal oxides. The selectivity of the sensor devices is controlled independent of the surface properties of the nanowire itself. It is the surface properties of the functionalizing metal oxides which determine the selectivity of these sensors. Further facilitated by the proposed fabrication technique, these sensors can be easily tuned to detect different gases. The prototype developed in this work is that of a UV assisted alcohol sensor using GaN nanowires functionalized with ZnO and SnO2 nanoparticles. As opposed to the widely demonstrated metal oxide based sensors assisted by elevated temperature, the operation of photoconductive semiconductor sensor devices such as those fabricated in this work, can also be assisted by UV illumination at room temperature. Temperature assisted sensing requires an integrated on-chip heater, which could impose constraints on the

  14. A relative humidity sensing probe based on etched thin-core fiber coated with polyvinyl alcohol

    NASA Astrophysics Data System (ADS)

    Sun, Hao; Yang, Zaihang; Zhou, Libin; Liu, Nan; Gang, Tingting; Qiao, Xueguang; Hu, Manli

    2015-12-01

    A relative humidity (RH) sensing probe based on etched thin-core fiber (TCF) coated with polyvinyl alcohol (PVA) is proposed and experimentally demonstrated.This sensor is constructed by splicing a section of TCF with a single mode fiber (SMF), then part of the TCF's cladding is etched by hydrofluoric acid solution and finally the tip of TCF is coated with PVA. Experimental results demonstrate that this sensor can measure the ambient RH by demodulating the power variation of reflection spectrum. The power demodulation method make this sensor can ignore the temperature cross-sensitivity and have an extensive application prospect.

  15. Secured network sensor-based defense system

    NASA Astrophysics Data System (ADS)

    Wei, Sixiao; Shen, Dan; Ge, Linqiang; Yu, Wei; Blasch, Erik P.; Pham, Khanh D.; Chen, Genshe

    2015-05-01

    Network sensor-based defense (NSD) systems have been widely used to defend against cyber threats. Nonetheless, if the adversary finds ways to identify the location of monitor sensors, the effectiveness of NSD systems can be reduced. In this paper, we propose both temporal and spatial perturbation based defense mechanisms to secure NSD systems and make the monitor sensor invisible to the adversary. The temporal-perturbation based defense manipulates the timing information of published data so that the probability of successfully recognizing monitor sensors can be reduced. The spatial-perturbation based defense dynamically redeploys monitor sensors in the network so that the adversary cannot obtain the complete information to recognize all of the monitor sensors. We carried out experiments using real-world traffic traces to evaluate the effectiveness of our proposed defense mechanisms. Our data shows that our proposed defense mechanisms can reduce the attack accuracy of recognizing detection sensors.

  16. Electrochemical Sensors Based on Organic Conjugated Polymers

    PubMed Central

    Rahman, Md. Aminur; Kumar, Pankaj; Park, Deog-Su; Shim, Yoon-Bo

    2008-01-01

    Organic conjugated polymers (conducting polymers) have emerged as potential candidates for electrochemical sensors. Due to their straightforward preparation methods, unique properties, and stability in air, conducting polymers have been applied to energy storage, electrochemical devices, memory devices, chemical sensors, and electrocatalysts. Conducting polymers are also known to be compatible with biological molecules in a neutral aqueous solution. Thus, these are extensively used in the fabrication of accurate, fast, and inexpensive devices, such as biosensors and chemical sensors in the medical diagnostic laboratories. Conducting polymer-based electrochemical sensors and biosensors play an important role in the improvement of public health and environment because rapid detection, high sensitivity, small size, and specificity are achievable for environmental monitoring and clinical diagnostics. In this review, we summarized the recent advances in conducting polymer-based electrochemical sensors, which covers chemical sensors (potentiometric, voltammetric, amperometric) and biosensors (enzyme based biosensors, immunosensors, DNA sensors).

  17. Alcohol

    MedlinePlus

    ... Text Size: A A A Listen En Español Alcohol Wondering if alcohol is off limits with diabetes? Most people with diabetes can have a moderate amount of alcohol. Research has shown that there can be some ...

  18. Alcohol

    MedlinePlus

    If you are like many Americans, you drink alcohol at least occasionally. For many people, moderate drinking ... risky. Heavy drinking can lead to alcoholism and alcohol abuse, as well as injuries, liver disease, heart ...

  19. Gas Sensors Based on Electrospun Nanofibers

    PubMed Central

    Ding, Bin; Wang, Moran; Yu, Jianyong; Sun, Gang

    2009-01-01

    Nanofibers fabricated via electrospinning have specific surface approximately one to two orders of the magnitude larger than flat films, making them excellent candidates for potential applications in sensors. This review is an attempt to give an overview on gas sensors using electrospun nanofibers comprising polyelectrolytes, conducting polymer composites, and semiconductors based on various sensing techniques such as acoustic wave, resistive, photoelectric, and optical techniques. The results of sensing experiments indicate that the nanofiber-based sensors showed much higher sensitivity and quicker responses to target gases, compared with sensors based on flat films. PMID:22573976

  20. Gas sensors based on electrospun nanofibers.

    PubMed

    Ding, Bin; Wang, Moran; Yu, Jianyong; Sun, Gang

    2009-01-01

    Nanofibers fabricated via electrospinning have specific surface approximately one to two orders of the magnitude larger than flat films, making them excellent candidates for potential applications in sensors. This review is an attempt to give an overview on gas sensors using electrospun nanofibers comprising polyelectrolytes, conducting polymer composites, and semiconductors based on various sensing techniques such as acoustic wave, resistive, photoelectric, and optical techniques. The results of sensing experiments indicate that the nanofiber-based sensors showed much higher sensitivity and quicker responses to target gases, compared with sensors based on flat films. PMID:22573976

  1. Can intensive use of alcohol-based hand rubs lead to passive alcoholization?

    PubMed

    Bessonneau, Vincent; Clément, Michel; Thomas, Olivier

    2010-08-01

    Hand disinfection with alcohols-based hand rubs (ABHRs) are known to be the most effective measure to prevent nosocomial infections in healthcare. ABHRs contain on average 70% by weight of one or more alcohols. During the hand rubbing procedure, users are exposed to these alcohols not only through dermal contact, but also via inhalation, due to the physical and chemical properties of alcohols volatilizing from alcoholic solutions or gels into the air. Ethanol ingestion is well known to increase risks of several diseases (affecting the pancreas, liver, cardiovascular system…), but there is a lack of knowledge about the effects of exposure to other alcohols (including n- or isopropanol) via inhalation and dermal contact, despite the worldwide use of ABHRs. This work aims at discussing possible health effects related to unintentional alcoholization (via inhalation and dermal contact) from professional ABHR usage to suggest the need for more research in this area (but not to question the value of ABHRs). Based upon an average of 30 hand rubbings per healthcare professional per day, it can be assumed that a healthcare worker may be exposed to a maximum 5,500 mg/m(3) per work shift, five times above the recommended occupational time weighted average limit. Thus, in order to answer the question posed in the title, studies on spatial and temporal variability of alcohol emission from ABHRs in real world situations and studies on certain high risk individuals are needed. PMID:20948945

  2. Can Intensive Use of Alcohol-Based Hand Rubs Lead to Passive Alcoholization?

    PubMed Central

    Bessonneau, Vincent; Clément, Michel; Thomas, Olivier

    2010-01-01

    Hand disinfection with alcohols-based hand rubs (ABHRs) are known to be the most effective measure to prevent nosocomial infections in healthcare. ABHRs contain on average 70% by weight of one or more alcohols. During the hand rubbing procedure, users are exposed to these alcohols not only through dermal contact, but also via inhalation, due to the physical and chemical properties of alcohols volatilizing from alcoholic solutions or gels into the air. Ethanol ingestion is well known to increase risks of several diseases (affecting the pancreas, liver, cardiovascular system…), but there is a lack of knowledge about the effects of exposure to other alcohols (including n- or isopropanol) via inhalation and dermal contact, despite the worldwide use of ABHRs. This work aims at discussing possible health effects related to unintentional alcoholization (via inhalation and dermal contact) from professional ABHR usage to suggest the need for more research in this area (but not to question the value of ABHRs). Based upon an average of 30 hand rubbings per healthcare professional per day, it can be assumed that a healthcare worker may be exposed to a maximum 5,500 mg/m3 per work shift, five times above the recommended occupational time weighted average limit. Thus, in order to answer the question posed in the title, studies on spatial and temporal variability of alcohol emission from ABHRs in real world situations and studies on certain high risk individuals are needed. PMID:20948945

  3. Alcohol

    MedlinePlus

    ... Got Homework? Here's Help White House Lunch Recipes Alcohol KidsHealth > For Kids > Alcohol Print A A A Text Size What's in ... What Is Alcoholism? Say No en español El alcohol Getting the Right Message "Hey, who wants a ...

  4. Displays, Memories, and Sensors Based on Organic Transistors

    NASA Astrophysics Data System (ADS)

    Katz, Howard

    2002-03-01

    For many applications of organic transistor-based electronics, properties other than mobility may be determining factors. In this work, we consider four "higher order" applications: an electrophoretic pixel switch, a complementary voltage inverter, a simple nonvolatile memory element, and a chemical sensor array, and discuss the particular device and material properties that need to be optimized for each one. The pixel switch requires minimal off current, the inverter depends on an ambipolar (hole carrying and electron carrying) transistor pair, the memory depends on a dielectric-semiconductor pairing in which both charge storage and threshold voltage adjustment occur, and the sensor is based on reversible and selective chemical interaction between an analyte and the semiconductor. Achievements reported here include a dynamic range >10 for the inverter and memory element, and sensory discrimination between organic functional groups such as alcohols and ketones. Solution-based processes will also be emphasized.

  5. Tactile sensors based on conductive polymers

    NASA Astrophysics Data System (ADS)

    Castellanos-Ramos, Julian; Navas-Gonzalez, Rafael; Macicior, Haritz; Ochoteco, Estibalitz; Vidal-Verdú, Fernando

    2009-05-01

    This paper presents results from a few tactile sensors we have designed and fabricated. These sensors are based on a common approach that consists of placing a sheet of piezoresistive material on the top of a set of electrodes. If a force is exerted against the surface of the so obtained sensor, the contact area between the electrodes and the piezoresistive material changes. Therefore, the resistance at the interface changes. This is exploited as transconduction principle to measure forces and build advanced tactile sensors. For this purpose, we use a thin film of conductive polymers as the piezoresistive material. Specifically, a conductive water-based ink of these polymers is deposited by spin coating on a flexible plastic sheet, giving as a result a smooth, homogeneous and conducting thin film on it. The main interest in this procedure is it is cheap and it allows the fabrication of flexible and low cost tactile sensors. In this work we present results from sensors made with two technologies. First, we have used a Printed Circuit Board technology to fabricate the set of electrodes and addressing tracks. Then we have placed the flexible plastic sheet with the conductive polymer film on them to obtain the sensor. The result is a simple, flexible tactile sensor. In addition to these sensors on PCB, we have proposed, designed and fabricated sensors with a screen printing technology. In this case, the set of electrodes and addressing tracks are made by printing an ink based on silver nanoparticles. There is a very interesting difference with the other sensors, that consists of the use of an elastomer as insulation material between conductive layers. Besides of its role as insulator, this elastomer allows the modification of the force versus resistance relationship. It also improves the dynamic response of the sensor because it implements a restoration force that helps the sensor to relax quicker when the force is taken off.

  6. Flexible Hall sensors based on graphene.

    PubMed

    Wang, Zhenxing; Shaygan, Mehrdad; Otto, Martin; Schall, Daniel; Neumaier, Daniel

    2016-04-14

    The excellent electronic and mechanical properties of graphene provide a perfect basis for high performance flexible electronic and sensor devices. Here, we present the fabrication and characterization of flexible graphene based Hall sensors. The Hall sensors are fabricated on 50 μm thick flexible Kapton foil using large scale graphene grown by chemical vapor deposition technique on copper foil. Voltage and current normalized sensitivities of up to 0.096 V VT(-1) and 79 V AT(-1) were measured, respectively. These values are comparable to the sensitivity of rigid silicon based Hall sensors and are the highest values reported so far for any flexible Hall sensor devices. The sensitivity of the Hall sensor shows no degradation after being bent to a minimum radius of 4 mm, which corresponds to a tensile strain of 0.6%, and after 1000 bending cycles to a radius of 5 mm. PMID:26997245

  7. Flexible Hall sensors based on graphene

    NASA Astrophysics Data System (ADS)

    Wang, Zhenxing; Shaygan, Mehrdad; Otto, Martin; Schall, Daniel; Neumaier, Daniel

    2016-03-01

    The excellent electronic and mechanical properties of graphene provide a perfect basis for high performance flexible electronic and sensor devices. Here, we present the fabrication and characterization of flexible graphene based Hall sensors. The Hall sensors are fabricated on 50 μm thick flexible Kapton foil using large scale graphene grown by chemical vapor deposition technique on copper foil. Voltage and current normalized sensitivities of up to 0.096 V VT-1 and 79 V AT-1 were measured, respectively. These values are comparable to the sensitivity of rigid silicon based Hall sensors and are the highest values reported so far for any flexible Hall sensor devices. The sensitivity of the Hall sensor shows no degradation after being bent to a minimum radius of 4 mm, which corresponds to a tensile strain of 0.6%, and after 1000 bending cycles to a radius of 5 mm.

  8. Polymer-Based Carbon Monoxide Sensors

    NASA Technical Reports Server (NTRS)

    Homer, M. L.; Shevade, A. V.; Zhou, H.; Kisor, A. K.; Lara, L. M.; Yen, S.-P. S.; Ryan, M. A.

    2010-01-01

    Polymer-based sensors have been used primarily to detect volatile organics and inorganics; they are not usually used for smaller, gas phase molecules. We report the development and use of two types of polymer-based sensors for the detection of carbon monoxide. Further understanding of the experimental results is also obtained by performing molecular modeling studies to investigate the polymer-carbon monoxide interactions. The first type is a carbon-black-polymer composite that is comprised of a non-conducting polymer base that has been impregnated with carbon black to make it conducting. These chemiresistor sensors show good response to carbon monoxide but do not have a long lifetime. The second type of sensor has a non-conducting polymer base but includes both a porphyrin-functionalized polypyrrole and carbon black. These sensors show good, repeatable and reversible response to carbon monoxide at room temperature.

  9. Graphene-based charge sensors

    NASA Astrophysics Data System (ADS)

    Neumann, C.; Volk, C.; Engels, S.; Stampfer, C.

    2013-11-01

    We discuss graphene nanoribbon-based charge sensors and focus on their functionality in the presence of external magnetic fields and high frequency pulses applied to a nearby gate electrode. The charge detectors work well with in-plane magnetic fields of up to 7 T and pulse frequencies of up to 20 MHz. By analyzing the step height in the charge detector’s current at individual charging events in a nearby quantum dot, we determine the ideal operation conditions with respect to the applied charge detector bias. Average charge sensitivities of 1.3 × 10-3e Hz-1/2 can be achieved. Additionally, we investigate the back action of the charge detector current on the quantum transport through a nearby quantum dot. By varying the charge detector bias from 0 to 4.5 mV, we can increase the Coulomb peak currents measured at the quantum dot by a factor of around 400. Furthermore, we can completely lift the Coulomb blockade in the quantum dot.

  10. SiC-Based Gas Sensors

    NASA Technical Reports Server (NTRS)

    Chen, Liang-Yu; Hunter, Gary W.; Neudeck, Philip G.; Knight, Dak; Liu, C. C.; Wu, Q. H.

    1997-01-01

    Electronic grade Silicon Carbide (SiC) is a ceramic material which can operate as a semiconductor at temperatures above 600 C. Recently, SiC semiconductors have been used in Schottky diode gas sensor structures. These sensors have been shown to be functional at temperatures significantly above the normal operating range of Si-based devices. SiC sensor operation at these higher temperatures allows detection of gases such as hydrocarbons which are not detectable at lower temperatures. This paper discusses the development of SiC-based Schottky diode gas sensors for the detection of hydrogen, hydrocarbons, and nitrogen oxides (NO(x)). Sensor designs for these applications are discussed. High sensitivity is observed for the hydrogen and hydrocarbon sensors using Pd on SiC Schottky diodes while the NO(x) sensors are still under development. A prototype sensor package has been fabricated which allows high temperature operation in a room temperature ambient by minimizing heat loss to that ambient. It is concluded that SiC-based gas sensors have considerable potential in a variety of gas sensing applications.

  11. SiC-Based Gas Sensor Development

    NASA Technical Reports Server (NTRS)

    Hunter, G. W.; Neudeck, P. G.; Gray, M.; Androjna, D.; Chen, L.-Y.; Hoffman, R. W., Jr.; Liu, C. C.; Wu, Q. H.

    2000-01-01

    Silicon carbide based Schottky diode gas sensors are being developed for applications such as emission measurements and leak detection. The effects of the geometry of the tin oxide film in a Pd/SnO2/SiC structure will be discussed as well as improvements in packaging SiC-based sensors. It is concluded that there is considerable versatility in the formation of SiC-based Schottky diode gas sensing structures which will potentially allow the fabrication of a SiC-based gas sensor array for a variety of gases and temperatures.

  12. [A USB-Based Digital ECG Sensor].

    PubMed

    Shi Bol; Kong, Xiangyong; Ma, Xiaozhi; Zhang, Genxuan

    2016-01-01

    Based on the ECG-specific BMD 101 integrated circun chip, this study designed a digital ECG sensor. In practical application, users just need to connect the ECG sensor 'o upper computer (such as PC or mobile phone) through USB interface, to realize the functions including display, alarm, saving, transfer etc. After tests, They demonstrate that the sensor can be applied to the detection of arrhythmia, such as bigeminy coupled rhythm, proiosystole etc. Besides, the sensor has various advantages in monitoring an managing the heart health of people out of hospital, including low cost, small volume, usableness, simplicity of operation etc. PMID:27197497

  13. Few-mode fiber based optical sensors.

    PubMed

    Li, An; Wang, Yifei; Hu, Qian; Shieh, William

    2015-01-26

    Few-mode fibers (FMFs) have found applications in optical communications and sensors with attractive features that standard single mode fiber (SSMF) do not possess. We report our recent progress on FMF based optical sensors, and show the potential of utilizing the spatial dimension for multi-parameter sensing with discrimination capability. We first show a discrete type FMF sensor based on interferometer structure with a short FMF, utilizing the modal interference between either the polarizations (x and y) or the spatial modes (LP(01) and LP(11)). We then show a distributed type FMF sensor by generating the stimulated Brillouin scattering (SBS) in a long FMF. We characterize the Brillouin gain spectrum (BGS) with a pump-probe configuration, and measure the temperature and strain coefficients for LP(01) and LP(11) modes. The proposed FMF based optical sensor can be applied to sensing a wide range of parameters. PMID:25835874

  14. Alcohol

    MedlinePlus

    ... as well as injuries, liver disease, heart disease, cancer, and other health problems. It can also cause problems at home, at work, and with friends. NIH: National Institute on Alcohol Abuse and Alcoholism

  15. Model-Based Method for Sensor Validation

    NASA Technical Reports Server (NTRS)

    Vatan, Farrokh

    2012-01-01

    Fault detection, diagnosis, and prognosis are essential tasks in the operation of autonomous spacecraft, instruments, and in situ platforms. One of NASA s key mission requirements is robust state estimation. Sensing, using a wide range of sensors and sensor fusion approaches, plays a central role in robust state estimation, and there is a need to diagnose sensor failure as well as component failure. Sensor validation can be considered to be part of the larger effort of improving reliability and safety. The standard methods for solving the sensor validation problem are based on probabilistic analysis of the system, from which the method based on Bayesian networks is most popular. Therefore, these methods can only predict the most probable faulty sensors, which are subject to the initial probabilities defined for the failures. The method developed in this work is based on a model-based approach and provides the faulty sensors (if any), which can be logically inferred from the model of the system and the sensor readings (observations). The method is also more suitable for the systems when it is hard, or even impossible, to find the probability functions of the system. The method starts by a new mathematical description of the problem and develops a very efficient and systematic algorithm for its solution. The method builds on the concepts of analytical redundant relations (ARRs).

  16. Recent Advances in Paper-Based Sensors

    PubMed Central

    Liana, Devi D.; Raguse, Burkhard; Gooding, J. Justin; Chow, Edith

    2012-01-01

    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. PMID:23112667

  17. Alcoholism.

    ERIC Educational Resources Information Center

    Caliguri, Joseph P., Ed.

    This extensive annotated bibliography provides a compilation of documents retreived from a computerized search of the ERIC, Social Science Citation Index, and Med-Line databases on the topic of alcoholism. The materials address the following areas of concern: (1) attitudes toward alcohol users and abusers; (2) characteristics of alcoholics and…

  18. Chemical Sensors Based on Metal Oxide Nanostructures

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W.; Xu, Jennifer C.; Evans, Laura J.; VanderWal, Randy L.; Berger, Gordon M.; Kulis, Mike J.; Liu, Chung-Chiun

    2006-01-01

    This paper is an overview of sensor development based on metal oxide nanostructures. While nanostructures such as nanorods show significan t potential as enabling materials for chemical sensors, a number of s ignificant technical challenges remain. The major issues addressed in this work revolve around the ability to make workable sensors. This paper discusses efforts to address three technical barriers related t o the application of nanostructures into sensor systems: 1) Improving contact of the nanostructured materials with electrodes in a microse nsor structure; 2) Controling nanostructure crystallinity to allow co ntrol of the detection mechanism; and 3) Widening the range of gases that can be detected by using different nanostructured materials. It is concluded that while this work demonstrates useful tools for furt her development, these are just the beginning steps towards realizati on of repeatable, controlled sensor systems using oxide based nanostr uctures.

  19. Use of Novel Technology-Based Techniques to Improve Alcohol-Related Outcomes in Clinical Trials

    PubMed Central

    Gurvich, Eugenia M.; Kenna, George A.; Leggio, Lorenzo

    2013-01-01

    With a better understanding of the biologic basis of alcohol dependence and the considerable financial burden of alcohol abuse and dependence, the number of alcohol-related clinical pharmacotherapy trials has been on the rise. Subsequently, the potential to find efficacious treatments is more promising. Unfortunately, alcohol-related trials face a number of challenges, as a result of the difficulties that arise from traditional and outdated methods to collect data and ensure medication adherence. Novel technology-based assessments, such as ecological momentary assessment, interactive voice response, transdermal sensor and medication-event monitoring system provide a prospective solution—albeit not without possible concerns—to the difficulties faced in alcohol-related clinical trials. Clinical trials are meant to define the efficacy of the treatment and to determine an effective and safe dosage. However, due to lack of adherence a drug could inappropriately or mistakenly be judged as ineffective for treating a specific disorder. The described technologies may be important tools to prevent false negatives in validating drug efficacy, to provide consistency in clinical trials and to improve available data regarding the study of pharmacotherapies for alcohol dependence. PMID:23955872

  20. Information-based self-organization of sensor nodes of a sensor network

    DOEpatents

    Ko, Teresa H.; Berry, Nina M.

    2011-09-20

    A sensor node detects a plurality of information-based events. The sensor node determines whether at least one other sensor node is an information neighbor of the sensor node based on at least a portion of the plurality of information-based events. The information neighbor has an overlapping field of view with the sensor node. The sensor node sends at least one communication to the at least one other sensor node that is an information neighbor of the sensor node in response to at least one information-based event of the plurality of information-based events.

  1. Effects of alcohol intake on time-based event expectations.

    PubMed

    Kunchulia, Marina; Thomaschke, Roland

    2016-04-01

    Previous evidence suggests that alcohol affects various forms of temporal cognition. However, there are presently no studies investigating whether and how alcohol affects on time-based event expectations. Here, we investigated the effects of alcohol on time-based event expectations. Seventeen healthy volunteers, aged between 19 and 36 years, participated. We employed a variable foreperiod paradigm with temporally predictable events, mimicking a computer game. Error rate and reaction time were analyzed in placebo (0 g/kg), low dose (0.2 g/kg) and high dose (0.6 g/kg) conditions. We found that alcohol intake did not eliminate, but substantially reduced, the formation of time-based expectancy. This effect was stronger for high doses, than for low doses, of alcohol. As a result of our studies, we have evidence that alcohol intake impairs time-based event expectations. The mechanism by which the level of alcohol impairs time-based event expectations needs to be clarified by future research. PMID:26680768

  2. Telemedicine-Based Alcohol Services for Rural Offenders

    PubMed Central

    Staton-Tindall, Michele; Wahler, Elizabeth; Webster, J. Matthew; Godlaski, Theodore; Freeman, Rebecca; Leukefeld, Carl

    2016-01-01

    Research has consistently shown that alcohol use is a problem in rural communities and access to substance abuse treatment, particularly evidence-based treatment is limited. Because telemedicine has been shown to be effective in delivering services, this article presents a novel and innovative way of using telemedicine technology in the form of videoconferencing to deliver an evidence-based alcohol intervention (motivational enhancement therapy) with at-risk alcohol users in real-world settings (rural probation and parole offices). This article focuses on: (a) creating a profile of an at-risk group of rural alcohol users; (b) describing the evidence-based intervention; and (c) describing the innovative telemedicine-based service delivery approach. PMID:22867122

  3. Carbon nanotube array based sensor

    DOEpatents

    Lee, Christopher L.; Noy, Aleksandr; Swierkowski, Stephan P.; Fisher, Karl A.; Woods, Bruce W.

    2005-09-20

    A sensor system comprising a first electrode with an array of carbon nanotubes and a second electrode. The first electrode with an array of carbon nanotubes and the second electrode are positioned to produce an air gap between the first electrode with an array of carbon nanotubes and the second electrode. A measuring device is provided for sensing changes in electrical capacitance between the first electrode with an array of carbon nanotubes and the second electrode.

  4. Alcohol based fuels for automotive engines

    SciTech Connect

    Menrad, H.K.

    1980-02-01

    The effects of methanol and/or ethanol additions on various properties of gasolines are discussed. Both advantages and disadvantages of such mixtures are set forth. The necessary changes in engine design to accommodate such fuel mixtures are described. Successful use of blended fuels in diesel engines is described. The current status of alcohol fuels in actual use is also reported. (BLM)

  5. Supersensitive graphene-based gas sensor

    NASA Astrophysics Data System (ADS)

    Lebedev, A. A.; Lebedev, S. P.; Novikov, S. N.; Davydov, V. Yu.; Smirnov, A. N.; Litvin, D. P.; Makarov, Yu. N.; Levitskii, V. S.

    2016-03-01

    Epitaxial graphene layers are produced with the aid of thermal destruction of the surface of a semi-insulating SiC substrate. Raman spectroscopy and atomic-force microscopy are employed in the study of the film homogeneity. A prototype of the gas sensor based on the films is fabricated. The device is sensitive to the NO2 molecules at a level of 5 ppb (five particles per billion). A possibility of the industrial application of the sensor is discussed.

  6. A Raspberry Pi-Based Attitude Sensor

    NASA Astrophysics Data System (ADS)

    Sreejith, A. G.; Mathew, Joice; Sarpotdar, Mayuresh; Mohan, Rekhesh; Nayak, Akshata; Safonova, Margarita; Murthy, Jayant

    We have developed a lightweight low-cost attitude sensor, based on a Raspberry Pi, built with readily available commercial components. It can be used in experiments where weight and power are constrained, such as in high-altitude lightweight balloon flights. This attitude sensor will be used as a major building block in a closed-loop control system with driver motors to stabilize and point cameras and telescopes for astronomical observations from a balloon-borne payload.

  7. Reflection-based fiber specklegram sensor

    NASA Astrophysics Data System (ADS)

    Rodriguez-Cobo, L.; Lomer, M.; Ruiz-Lombera, R.; Cobo, A.; Lopez-Higuera, J. M.

    2016-05-01

    In this paper, a Fiber Specklegram Sensor (FSS) based on Plastic Optical Fiber (POF) has been proposed with a reflection-based configuration. A HeNe laser is launched through a coupler, reflected by a mirrored fiber end and detect the specklegram sequence using a commercial camera. Different sensor performance metrics have been analyzed in terms of final sensitivity to external vibration applied to the fiber. The results confirm the performance reduction of the reflection-based scheme in comparison with the transmission-based approach but it can be also employed as sensing system where only a single fiber end is available.

  8. Monitoring and Evaluation of Alcoholic Fermentation Processes Using a Chemocapacitor Sensor Array

    PubMed Central

    Oikonomou, Petros; Raptis, Ioannis; Sanopoulou, Merope

    2014-01-01

    The alcoholic fermentation of Savatiano must variety was initiated under laboratory conditions and monitored daily with a gas sensor array without any pre-treatment steps. The sensor array consisted of eight interdigitated chemocapacitors (IDCs) coated with specific polymers. Two batches of fermented must were tested and also subjected daily to standard chemical analysis. The chemical composition of the two fermenting musts differed from day one of laboratory monitoring (due to different storage conditions of the musts) and due to a deliberate increase of the acetic acid content of one of the musts, during the course of the process, in an effort to spoil the fermenting medium. Sensor array responses to the headspace of the fermenting medium were compared with those obtained either for pure or contaminated samples with controlled concentrations of standard ethanol solutions of impurities. Results of data processing with Principal Component Analysis (PCA), demonstrate that this sensing system could discriminate between a normal and a potential spoiled grape must fermentation process, so this gas sensing system could be potentially applied during wine production as an auxiliary qualitative control instrument. PMID:25184490

  9. Graphene oxide - Polyvinyl alcohol nanocomposite based electrode material for supercapacitors

    NASA Astrophysics Data System (ADS)

    Pawar, Pranav Bhagwan; Shukla, Shobha; Saxena, Sumit

    2016-07-01

    Supercapacitors are high capacitive energy storage devices and find applications where rapid bursts of power are required. Thus materials offering high specific capacitance are of fundamental interest in development of these electrochemical devices. Graphene oxide based nanocomposites are mechanically robust and have interesting electronic properties. These form potential electrode materials efficient for charge storage in supercapacitors. In this perspective, we investigate low cost graphene oxide based nanocomposites as electrode material for supercapacitor. Nanocomposites of graphene oxide and polyvinyl alcohol were synthesized in solution phase by integrating graphene oxide as filler in polyvinyl alcohol matrix. Structural and optical characterizations suggest the formation of graphene oxide and polyvinyl alcohol nanocomposites. These nanocomposites were found to have high specific capacitance, were cyclable, ecofriendly and economical. Our studies suggest that nanocomposites prepared by adding 0.5% wt/wt of graphene oxide in polyvinyl alcohol can be used an efficient electrode material for supercapacitors.

  10. Recent developments in OLED-based chemical and biological sensors

    NASA Astrophysics Data System (ADS)

    Shinar, Joseph; Zhou, Zhaoqun; Cai, Yuankun; Shinar, Ruth

    2007-09-01

    Recent developments in the structurally integrated OLED-based platform of luminescent chemical and biological sensors are reviewed. In this platform, an array of OLED pixels, which is structurally integrated with the sensing elements, is used as the photoluminescence (PL) excitation source. The structural integration is achieved by fabricating the OLED array and the sensing element on opposite sides of a common glass substrate or on two glass substrates that are attached back-to-back. As it does not require optical fibers, lens, or mirrors, it results in a uniquely simple, low-cost, and potentially rugged geometry. The recent developments on this platform include the following: (1) Enhancing the performance of gas-phase and dissolved oxygen sensors. This is achieved by (a) incorporating high-dielectric TiO II nanoparticles in the oxygen-sensitive Pt and Pd octaethylporphyrin (PtOEP and PdOEP, respectively)- doped polystyrene (PS) sensor films, and (b) embedding the oxygen-sensitive dyes in a matrix of polymer blends such as PS:polydimethylsiloxane (PDMS). (2) Developing sensor arrays for simultaneous detection of multiple serum analytes, including oxygen, glucose, lactate, and alcohol. The sensing element for each analyte consists of a PtOEP-doped PS oxygen sensor, and a solution containing the oxidase enzyme specific to the analyte. Each sensing element is coupled to two individually addressable OLED pixels and a Si photodiode photodetector (PD). (3) Enhancing the integration of the platform, whereby a PD array is also structurally integrated with the OLED array and sensing elements. This enhanced integration is achieved by fabricating an array of amorphous or nanocrystalline Si-based PDs, followed by fabrication of the OLED pixels in the gaps between these Si PDs.

  11. Bioinspired design of tactile sensors based on Flemion

    NASA Astrophysics Data System (ADS)

    Wang, Jin; Sato, Hiroshi; Xu, Chunye; Taya, Minoru

    2009-04-01

    In this work, we studied experimentally the sensing behavior of ionic membrane-based tactile sensors (Nafion and Flemion). We found from the experimental results that Flemion-based sensor exhibits clearer sensing signals than Nafion-based sensor and signals from Flemion-based sensor are robust under repeated loading. We also found that dome-shaped Flemion sensor can detect three-dimensional forces. We attempted to design an arrayed Flemion sensor system by bioinspiration from the tactile sensor cells on the skin of a cucumber tendril where numbers of the dome-shaped Flemion sensor units are arrayed periodically.

  12. A ferrofluid-based wireless pressure sensor

    NASA Astrophysics Data System (ADS)

    Chitnis, Girish; Ziaie, Babak

    2013-12-01

    This paper presents a wireless pressure sensor design based on magnetic fluid displacement over a planar coil and its corresponding inductance change. The design of the pressure sensor is presented followed by its fabrication and characterization. Experimental results show a good correlation with a nonlinear model relating the applied pressure to the change in coil self-resonant frequency. A prototype sensor (radius = 6 mm, thickness = 2 mm) based on the above principal using an oil-based ferrofluid (50 µl, ferrite concentration 2%), a polyimide-embedded planar coil (L = 1 µH), and a 25 µm thick polyimide membrane shows a sensitivity of 3 KHz mmHg-1 with a base-line resonant frequency of f0 = 109 MHz.

  13. A portable gas sensor based on cataluminescence.

    PubMed

    Kang, C; Tang, F; Liu, Y; Wu, Y; Wang, X

    2013-01-01

    We describe a portable gas sensor based on cataluminescence. Miniaturization of the gas sensor was achieved by using a miniature photomultiplier tube, a miniature gas pump and a simple light seal. The signal to noise ratio (SNR) was considered as the evaluation criteria for the design and testing of the sensor. The main source of noise was from thermal background. Optimal working temperature and flow rate were determined experimentally from the viewpoint of improvement in SNR. A series of parameters related to analytical performance was estimated. The limitation of detection of the sensor was 7 ppm (SNR = 3) for ethanol and 10 ppm (SNR = 3) for hydrogen sulphide. Zirconia and barium carbonate were respectively selected as nano-sized catalysts for ethanol and hydrogen sulphide. PMID:22736626

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

    PubMed

    Hakovirta, M; Aksoy, B; Hakovirta, J

    2015-08-01

    Natural self-assembled microstructured particles (diatomaceous earth) were used to develop a gas sensor paper with detection mechanism based on visible and distinct color changes of the sensor paper when exposed to volatile basic nitrogen compounds. The coating formulation for paper was prepared by applying diatomites, polyvinyl alcohol (PVOH), and pH sensitive dyes on acidic paper substrate. The surface coating was designed to allow a maximum gas flow through the diatomite sensors. The produced sensor paper was tested for sensitivity using different ammonia concentrations and we observed a sensitivity lower limit at 63 ppm. As a comparison, the results show comparable sensitivity levels to carbon nanotube based sensor technologies reported in literature. PMID:26042721

  15. Optical fiber sensor for pressure measurement based on elastomeric membrane and macrobending loss

    NASA Astrophysics Data System (ADS)

    Ribeiro, Livia A.; Rosolem, Joao B.; Dini, Danilo C.; Floridia, Claudio; Bezerra, Edson W.; Cezar, Fabio A.; Loichate, Marcelo D.; Durelli, Anderson S.

    2012-04-01

    We propose a fiber optic sensor array based on bend loss assessed by optical time domain reflectometry (OTDR). The sensor mechanism is based on optical fiber bending loss compressed by external pressure. An elastomeric surface is applied to the sensor in order to communicate external pressure to the fiber coil and also, this make sensor able to deal with degradation coming from aggressive environments. The sensing system proposed is able to monitor liquid or gas pressure in different environments, such as water, oil, alcohols, some diluted acids and others, depending only of elastomeric membrane choice. In order to protect the sensor stage against environmental degradation a plastic packaging was chosen. Bend loss measurements is taken concerning the number of fiber loops involved in the sensor, pump signal wavelength and temporal width. This long for the best parameters in the sensor construction. The specific case of the sensor applied to water percolation monitoring from embankment damns is detailed in this paper; for this application the sensor array have a number of at least six stages totally independent each other, in such a way that each stage can be developed to monitor a specific environment. Sensors have shown good performance in field tests, reaching work range from 0.1 to 0.6 atm with 0.05 atm of precision.

  16. Temperature sensor based on dielectric optical microresonator

    NASA Astrophysics Data System (ADS)

    Rahman, Anisur

    2011-12-01

    An optical temperature sensor has been presented based on Whispering Gallery Mode (WGM) dielectric microresonator. The effect of Transverse Electric (TE) wave propagation in dielectric micro-spheres presented has been for optical resonances based on WGM. TE waves are characterized both theoretically and experimentally for large size parameter of the micro-spheres. A theoretical model has been developed based on asymptotic approach. The theoretical development is mathematically robust and significantly less complicated than existing approaches presented in the literature. The quality factor of experimental resonance spectra observed in the laboratory is calculated approximately in the order of 10 4 which is sensitive enough to detect micro or nano level temperature changes in the surrounding medium. The sensitivity of the Morphology Dependent Resonance (MDR) temperature sensor is wavelength change of 10 -9 m for one degree centigrade change in temperature. This sensor could potentially be used for nano technology, Micro-Electro-Mechanical Systems (MEMS) devices, and biomedical applications.

  17. Alcohol.

    ERIC Educational Resources Information Center

    Schibeci, Renato

    1996-01-01

    Describes the manufacturing of ethanol, the effects of ethanol on the body, the composition of alcoholic drinks, and some properties of ethanol. Presents some classroom experiments using ethanol. (JRH)

  18. Pristine carbon nanotubes based resistive temperature sensor

    NASA Astrophysics Data System (ADS)

    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.

  19. Wearable tactile sensor based on flexible microfluidics.

    PubMed

    Yeo, Joo Chuan; Yu, Jiahao; Koh, Zhao Ming; Wang, Zhiping; Lim, Chwee Teck

    2016-08-16

    In this work, we develop a liquid-based thin film microfluidic tactile sensor of high flexibility, robustness and sensitivity. The microfluidic elastomeric structure comprises a pressure sensitive region and parallel arcs that interface with screen-printed electrodes. The microfluidic sensor is functionalized with a highly conductive metallic liquid, eutectic gallium indium (eGaIn). Microdeformation on the pressure sensor results in fluid displacement which corresponds to a change in electrical resistance. By emulating parallel electrical circuitry in our microchannel design, we reduced the overall electrical resistance of the sensor, therefore enhancing its device sensitivity. Correspondingly, we report a device workable within a range of 4 to 100 kPa and sensitivity of up to 0.05 kPa(-1). We further demonstrate its robustness in withstanding >2500 repeated loading and unloading cycles. Finally, as a proof of concept, we demonstrate that the sensors may be multiplexed to detect forces at multiple regions of the hand. In particular, our sensors registered unique electronic signatures in object grasping, which could provide better assessment of finger dexterity. PMID:27438370

  20. Renewable Reagent Fiber Optic Based Ammonia Sensor

    NASA Astrophysics Data System (ADS)

    Berman, Richard J.; Burgess, Lloyd W.

    1990-02-01

    Many fiber optic based chemical sensors have been described which rely on a reagent chemistry fixed at the fiber endface to provide analyte specificity. In such systems, problems involving probe-to-probe reproducibility, reagent photolability and reagent leaching are frequently encountered. As a result, calibration and standardization of these sensors becomes difficult or impossible and thus inhibits their application for long term in situ chemical monitoring. Many of these problems can be addressed and several additional advantages gained by continuously renewing the reagent chemistry. To illustrate this concept, a fiber optic ammonia sensor is described in which the reagent is delivered under direct control to a sensing volume of approximately 400 nanoliters located at the probe tip. Using an acid-base indicator (bromothymol blue) as the reagent, the sample ammonia concentrations are related to modulations in light intensity with a lower limit of detection of 10 ppb. The sensor performance was studied with respect to reagent pH, concentration and reagent delivery rate. Compared with previous fiber optic ammonia sensors, the ability to reproducibly renew the reagent has resulted in improvements with respect to response and return times, probe-to-probe reproducibility, probe lifetime and flexibility of use.

  1. Sensitivity and Response of Polyvinyl Alcohol/Tin Oxide Nanocomposite Multilayer Thin Film Sensors.

    PubMed

    Sriram, G; Dhineshbabu, N R; Nithyavathy, N; Saminathan, K; Kaler, K V I S; Rajendran, V

    2016-01-01

    Nanocrystalline Tin Oxide (SnO₂) is Non-Stoichiometric in Nature with Functional Properties Suitable for gas sensing. In this study, SnO₂nanoparticles were prepared by the sol-gel technique, which were then characterised using X-ray diffraction. The nanoparticles showed tetragonal structure with an average crystallite size of 18 nm. The stretching and vibration modes of SnO₂were confirmed using Fourier transform infrared spectroscopy. The size of SnO₂ nanoparticles was determined using particle size analyser, which was found be 60 ± 10 nm on average. The surface morphology of the nanoparticles was investigated using scanning electron microscope, which showed irregular-sized agglomerated SnO₂nanostructures. In addition, primary particle size was evaluated using high-resolution transmission electron microscopy, which was found to be 50 nm on average. The polyvinyl alcohol/SnO₂ composite thin film was prepared on a glass substrate using spin-coating method. The values of band gap energy and electrical conductance of 13-layer thin film were found to be 2.96 eV and 0.0505 mho, respectively. Sulfur dioxide (SO₂) was suitably tailored to verify the sensor response over a concentration range of 10-70 ppm at room temperature. The performance, response, and recovery time of sensors were increased by increasing the layers of the thin film. PMID:27398561

  2. Preparation and characterisation of ZnFe 2O 4/ZnO polymer nanocomposite sensors for the detection of alcohol vapours

    NASA Astrophysics Data System (ADS)

    Arshak, K.; Moore, E.; Cunniffe, C.; Nicholson, M.; Arshak, A.

    2007-07-01

    During the last 10 years, a large interest has developed in the preparation of nanocomposite structures by embedding inorganic nanoparticles into polymeric materials. These materials combine the properties of the inorganic fillers with the processability and flexibility of polymers. The versatility of polymer nanocomposite systems is of special interest to the gas sensor industry where arrays of polymer/carbon black composites have been used to identify gases and odours. These polymer gas sensors provide selectivity based on their chemical structures and operate at room temperature, which provide advantages over thick-film metal oxide gas sensors. ZnFe 2O 4 and ZnO have excellent stability, high sensitivity, low fabrication complexity and moderate operating temperatures, which are ideal properties for a gas sensing material. In this work, the development of a thick-film ZnFe 2O 4/ZnO sensor, which operates at room temperature and a drop-coated conducting polymer composite sensor containing 30 w/w% ZnFe 2O 4/ZnO nanoparticles is discussed. The sensors were tested in a fully automated test rig and showed promising results for the detection of alcohol vapours.

  3. Optical Sensor Based Corn Algorithm Evaluation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Optical sensor based algorithms for corn fertilization have developed by researchers in several states. The goal of this international research project was to evaluate these different algorithms and determine their robustness over a large geographic area. Concurrently the goal of this project was to...

  4. Portable nanoparticle based sensors for antioxidant analysis.

    PubMed

    Sharpe, Erica; Andreescu, Silvana

    2015-01-01

    Interest in portable sensing devices has increased throughout the past decade. Portable sensors are convenient for use in remote locations and in places with limited resources for advanced instrumentation. Often such devices utilize advanced technology that allows the final user to simply deposit the sample onto the sensing platform without preparation of multiple reagents. Herein, we describe preparation and characterization of a colorimetric paper-based metal oxide sensing array designed for the field detection of polyphenolic antioxidants. This sensor is a good candidate for use in analysis of the antioxidant character of food, drink, botanical medicines, physiological fluids, and more. PMID:25323510

  5. Biomaterial based sulphur di oxide gas sensor

    NASA Astrophysics Data System (ADS)

    Ghosh, P. K.; Sarkar, A.

    2013-06-01

    Biomaterials are getting importance in the present research field of sensors. In this present paper performance of biomaterial based gas sensor made of gum Arabica and garlic extract had been studied. Extract of garlic clove with multiple medicinal and chemical utility can be proved to be useful in sensing Sulphur di Oxide gas. On exposure to Sulphur di Oxide gas the material under observation suffers some temporary structural change, which can be observed in form of amplified potentiometric change through simple electronic circuitry. Exploiting this very property a potentiometric gas sensor of faster response and recovery time can be designed. In this work sensing property of the said material has been studied through DC conductance, FTIR spectrum etc.

  6. Physiological roles of acid-base sensors.

    PubMed

    Levin, Lonny R; Buck, Jochen

    2015-01-01

    Acid-base homeostasis is essential for life. The macromolecules upon which living organisms depend are sensitive to pH changes, and physiological systems use the equilibrium between carbon dioxide, bicarbonate, and protons to buffer their pH. Biological processes and environmental insults are constantly challenging an organism's pH; therefore, to maintain a consistent and proper pH, organisms need sensors that measure pH and that elicit appropriate responses. Mammals use multiple sensors for measuring both intracellular and extracellular pH, and although some mammalian pH sensors directly measure protons, it has recently become apparent that many pH-sensing systems measure pH via bicarbonate-sensing soluble adenylyl cyclase. PMID:25340964

  7. Diaphragm based high sensitive FBG pressure sensor

    NASA Astrophysics Data System (ADS)

    Vengal Rao, P.; Srimannarayana, K.; Sai Shankar, M.; Kishore, P.

    2013-06-01

    A high sensitive pressure sensor based on Fiber Bragg grating (FBG) integrated with a thin metal diaphragm was designed and demonstrated. To enhance the pressure sensitivity FBG is firmly glued across the diameter of the diaphragm. Under pressure, the diaphragm deforms and produces an induced strain along the length of the fiber causes shift in Bragg wavelength of the FBG. Pressure measurement is made by measuring the Bragg wavelength shift against change in pressure. The sensor was tested up to the maximum pressure of 140 psi and the corresponding pressure sensitivity was found to be 0.0204 nm/psi, which is approximately 970 times higher than that can be achieved with a bare FBG. The experimental results show good agreement with the theoretical results and possess good linearity and repeatability. This sensor can be used for the measurement of medium pressure, liquid level and depth of underwater.

  8. Paper-Based Electrical Respiration Sensor.

    PubMed

    Güder, Firat; Ainla, Alar; Redston, Julia; Mosadegh, Bobak; Glavan, Ana; Martin, T J; Whitesides, George M

    2016-05-01

    Current methods of monitoring breathing require cumbersome, inconvenient, and often expensive devices; this requirement sets practical limitations on the frequency and duration of measurements. This article describes a paper-based moisture sensor that uses the hygroscopic character of paper (i.e. the ability of paper to adsorb water reversibly from the surrounding environment) to measure patterns and rate of respiration by converting the changes in humidity caused by cycles of inhalation and exhalation to electrical signals. The changing level of humidity that occurs in a cycle causes a corresponding change in the ionic conductivity of the sensor, which can be measured electrically. By combining the paper sensor with conventional electronics, data concerning respiration can be transmitted to a nearby smartphone or tablet computer for post-processing, and subsequently to a cloud server. This means of sensing provides a new, practical method of recording and analyzing patterns of breathing. PMID:27059088

  9. Electrochemical Sensors Based on Carbon Nanotubes

    PubMed Central

    Saleh Ahammad, A. J.; Lee, Jae-Joon; Rahman, Md. Aminur

    2009-01-01

    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. PMID:22574013

  10. Fluorescent sensors based on boronic acids

    NASA Astrophysics Data System (ADS)

    Cooper, Christopher R.; James, Tony D.

    1999-05-01

    Sensor systems have long been needed for detecting the presence in solution of certain chemically or biologically important species. Sensors are used in a wide range of applications from simple litmus paper that shows a single color change in acidic or basic environments to complex biological assays that use enzymes, antibodies and antigens to display binding events. With this work the use of boronic acids in the design and synthesis of sensors for saccharides (diols) will be presented. The fluorescent sensory systems rely on photoinduced electron transfer (PET) to modulate the observed fluorescence. When saccharides form cyclic boronate esters with boronic acids, the Lewis acidity of the boronic acid is enhanced and therefore the Lewis acid-base interaction between the boronic acid and a neighboring amine is strengthened. The strength of this acid-base interaction modulates the PET from the amine (acting as a quencher) to anthracene (acting as a fluorophore). These compounds show increased fluorescence at neutral pH through suppression of the PET from nitrogen to anthracene on saccharide binding. The general strategy for the development of saccharide selective systems will be discussed. The potential of the boronic acid based systems will be illustrated using the development of glucose and glucosamine selective fluorescent sensors as examples.

  11. Fetal alcohol syndrome prevention using community-based narrowcasting campaigns.

    PubMed

    Glik, Deborah; Prelip, Michael; Myerson, Amy; Eilers, Katie

    2008-01-01

    Preventing fetal alcohol syndrome (FAS) by encouraging pregnant women to abstain from drinking alcohol competes with commercial alcohol marketing. Two FAS-prevention campaigns using a narrowcast approach among young women of childbearing age in two disadvantaged Southern California communities are compared. The design, implementation process, and degree to which campaigns reached the priority populations are the focus of this article. Formative research shows that young women in disadvantaged communities receive mixed messages about dangers of drinking during pregnancy. A social norms approach using positive role models was the most acceptable message strategy based on materials pretesting. Differences in campaign implementation and distribution strategies between communities were documented through program monitoring. Survey research indicated the more viable messaging and implementation strategies. Findings show that low-cost community campaigns are feasible; however, variations in messaging, distribution strategies, and saturation levels determine whether such campaigns succeed or fail to reach priority populations. PMID:18166669

  12. Sensor-based interior modeling

    SciTech Connect

    Herbert, M.; Hoffman, R.; Johnson, A.; Osborn, J.

    1995-02-01

    Robots and remote systems will play crucial roles in future decontamination and decommissioning (D&D) of nuclear facilities. Many of these facilities, such as uranium enrichment plants, weapons assembly plants, research and production reactors, and fuel recycling facilities, are dormant; there is also an increasing number of commercial reactors whose useful lifetime is nearly over. To reduce worker exposure to radiation, occupational and other hazards associated with D&D tasks, robots will execute much of the work agenda. Traditional teleoperated systems rely on human understanding (based on information gathered by remote viewing cameras) of the work environment to safely control the remote equipment. However, removing the operator from the work site substantially reduces his efficiency and effectiveness. To approach the productivity of a human worker, tasks will be performed telerobotically, in which many aspects of task execution are delegated to robot controllers and other software. This paper describes a system that semi-automatically builds a virtual world for remote D&D operations by constructing 3-D models of a robot`s work environment. Planar and quadric surface representations of objects typically found in nuclear facilities are generated from laser rangefinder data with a minimum of human interaction. The surface representations are then incorporated into a task space model that can be viewed and analyzed by the operator, accessed by motion planning and robot safeguarding algorithms, and ultimately used by the operator to instruct the robot at a level much higher than teleoperation.

  13. Alcohol Use Problem Severity and Problem Behavior Engagement among School-Based Youths in Minnesota

    ERIC Educational Resources Information Center

    Mancha, Brent E.; Rojas-Neese, Vanessa C.; Latimer, William W.

    2010-01-01

    This study created an alcohol use problem severity taxonomy and examined its association to engagement in other problem behaviors. Minnesota youths were categorized based on their frequency of alcohol use and DSM-IV alcohol abuse and dependence criteria. Greater alcohol use problem severity was generally associated with higher prevalence of…

  14. The Employee Stress and Alcohol Project: the development of a computer-based alcohol abuse prevention program for employees.

    PubMed

    Matano, R A; Futa, K T; Wanat, S F; Mussman, L M; Leung, C W

    2000-05-01

    The Employee Stress and Alcohol Project (ESAP) developed an interactive computer-based alcohol abuse prevention and early intervention program accessible to employees over the Internet. Behavioral health research recommends that specialists develop and provide comprehensive yet cost-effective approaches to alcohol abuse prevention, early intervention, and treatment within the context of workplace managed care. ESAP is implementing this web site for a diverse 8,567-employee work site. ESAP's web site enables employees to self-assess their stress levels, coping styles, and risk for alcohol-related problems. It provides personalized feedback, recommendations, mini-workshops, a drinking journal, links to other online resources, and an interactive forum for direct participant-to-participant communication. ESAP's web site provides resources for employees who are concerned about another individual's drinking as well as information about adolescent alcohol use. This article discusses the implications of incorporating the ESAP web site into worksite alcohol abuse prevention and early intervention programming. PMID:10795126

  15. Voucher-Based Reinforcement for Alcohol Abstinence Using the Ethyl-Glucuronide Alcohol Biomarker

    ERIC Educational Resources Information Center

    McDonell, Michael G.; Howell, Donelle N,; McPherson, Sterling; Cameron, Jennifer M.; Srebnik, Debra; Roll, John M.; Ries, Richard K.

    2012-01-01

    This study assessed the effects of a contingency management (CM) intervention for alcohol consumption in 10 alcohol-dependent participants. An ABCA design was used. Vouchers were provided contingent on results of ethyl glucuronide (EtG) urine tests (an alcohol biomarker with a 2-day detection period) and alcohol breath tests during the C phase.…

  16. Carbon nanotube based NEMS actuators and sensors

    NASA Astrophysics Data System (ADS)

    Forney, Michael; Poler, Jordan

    2011-03-01

    Single-walled carbon nanotubes (SWNTs) have been widely studied due to superior mechanical and electrical properties. We have grown vertically aligned SWNTs (VA-SWNTs) onto microcantilever (MC) arrays, which provides an architecture for novel actuators and sensors. Raman spectroscopy confirms that the CVD-grown nanotubes are SWNTs and SEM confirms aligned growth. As an actuator, this hybrid MC/VA-SWNT system can be electrostatically modulated. SWNTs are excellent electron acceptors, so we can charge up the VA-SWNT array by applying a voltage. The electrostatic repulsion among the charged SWNTs provides a surface stress that induces MC deflection. Simulation results show that a few electrons per SWNT are needed for measureable deflections, and experimental actuators are being characterized by SEM, Raman, and an AFM optical lever system. The applied voltage is sinusoidally modulated, and deflection is measured with a lock-in amplifier. These actuators could be used for nano-manipulation, release of drugs from a capsule, or nano-valves. As a sensor, this MC/VA-SWNT system offers an improved sensitivity for chemical and bio-sensing compared to surface functionalized MC-based sensors. Those sensors only have a 2D sensing surface, but a MC/VA-SWNT system has significantly more sensing surface because the VA-SWNTs extend microns off the MC surface.

  17. Wavefront reconstruction using smartphone based wavefront sensors

    NASA Astrophysics Data System (ADS)

    Yang, Zhenyu; Zhan, Qiwen

    2015-11-01

    Smartphone camera system has the capability of being integrated into powerful field-sensing tools, capturing data and sharing these data with computing servers or cloud experts. The purpose of this work is to implement a wavefront sensor based on the smartphone platform, which has many potential applications in thin-films and bio-related sensing areas. To overcome problems caused by traditional wavefront curvature sensing setups, distorted micro-gratings are designed and introduced into the system in the dual role of both beam splitter and defocuser. The new design is capable of capturing two images of different levels of defocus in a single shot, which are then used as the input data to reconstruct the wavefront. Through testing with generated known spherical wavefronts, the smartphone based wavefront sensor has demonstrated decent system resolution and wavefront sensing accuracy.

  18. Magnetocardiography with sensors based on giant magnetoresistance

    NASA Astrophysics Data System (ADS)

    Pannetier-Lecoeur, M.; Parkkonen, L.; Sergeeva-Chollet, N.; Polovy, H.; Fermon, C.; Fowley, C.

    2011-04-01

    Biomagnetic signals, mostly due to the electrical activity in the body, are very weak and they can only be detected by the most sensitive magnetometers, such as Superconducting Quantum Interference Devices (SQUIDs). We report here biomagnetic recordings with hybrid sensors based on Giant MagnetoResistance (GMR). We recorded magnetic signatures of the electric activity of the human heart (magnetocardiography) in healthy volunteers. The P-wave and QRS complex, known from the corresponding electric recordings, are clearly visible in the recordings after an averaging time of about 1 min. Multiple recordings at different locations over the chest yielded a dipolar magnetic field map and allowed localizing the underlying current sources. The sensitivity of the GMR-based sensors is now approaching that of SQUIDs and paves way for spin electronics devices for functional imaging of the body.

  19. Temperature Sensors Based on WGM Optical Resonators

    NASA Technical Reports Server (NTRS)

    Savchenkov, Anatoliy; Yu, Nan; Maleki, Lute; Itchenko, Vladimir; Matsko, Andrey; Strekalov, Dmitry

    2008-01-01

    A proposed technique for measuring temperature would exploit differences between the temperature dependences of the frequencies of two different electromagnetic modes of a whispering gallery-mode (WGM) optical resonator. An apparatus based on this technique was originally intended to be part of a control system for stabilizing a laser frequency in the face of temperature fluctuations. When suitably calibrated, apparatuses based on this technique could also serve as precise temperature sensors for purposes other than stabilization of lasers. A sensor according to the proposal would include (1) a transparent WGM dielectric resonator having at least two different sets of modes characterized by different thermo-optical constants and (2) optoelectronic instrumentation for measuring the difference between the temperature-dependent shifts of the resonance frequencies of the two sets of modes.

  20. Monitoring of Temperature Fatigue Failure Mechanism for Polyvinyl Alcohol Fiber Concrete Using Acoustic Emission Sensors

    PubMed Central

    Li, Dongsheng; Cao, Hai

    2012-01-01

    The applicability of acoustic emission (AE) techniques to monitor the mechanism of evolution of polyvinyl alcohol (PVA) fiber concrete damage under temperature fatigue loading is investigated. Using the temperature fatigue test, real-time AE monitoring data of PVA fiber concrete is achieved. Based on the AE signal characteristics of the whole test process and comparison of AE signals of PVA fiber concretes with different fiber contents, the damage evolution process of PVA fiber concrete is analyzed. Finally, a qualitative evaluation of the damage degree is obtained using the kurtosis index and b-value of AE characteristic parameters. The results obtained using both methods are discussed. PMID:23012555

  1. Literacy-Based Supports for Young Adults with FAS/FAE [Fetal Alcohol Syndrome/Fetal Alcohol Effects].

    ERIC Educational Resources Information Center

    Raymond, Margaret; Belanger, Joe

    During a 1-year period, a study investigated the contributions made by 3 literacy-based supports (support circles, cognitive compensatory tools, and cognitive enhancement tools) to the lives of 5 young adults, aged 16-34, with FAS/FAE (Fetal Alcohol Syndrome/Fetal Alcohol Effects). Four of the five subjects had IQs (intelligence quotients) above…

  2. Web-based treatment of alcohol problems among rural women.

    PubMed

    Finfgeld-Connett, Deborah; Madsen, Richard

    2008-09-01

    It is estimated that 6 million women in the United States misuse alcohol. Of that number, many live in rural areas and face numerous barriers to treatment. The World Wide Web has the potential to help such individuals overcome these barriers. In light of emergent findings supporting the effectiveness of online alcohol treatment services for women, a randomized pilot study was conducted to evaluate a Web-based, self-guided alcohol treatment program. Eligible women were randomized to standard care or an online treatment program. Web-based treatment components included gender-specific reference modules and decision making modules, an asynchronous bulletin board, and a synchronous chat feature. The average age of the participants (N = 44) was 50 (SD = 11 years), and their baseline Alcohol Use Disorders Identification Test score was 18 (SD = 6), with 8 being the cut-off score for problem drinking. At 3-month follow up, both treatment groups decreased their drinking; however, no significant differences were found between them. PMID:18823000

  3. Nanomaterial-based robust oxygen sensor

    NASA Astrophysics Data System (ADS)

    Goswami, Kisholoy; Sampathkumaran, Uma; Alam, Maksudul; Tseng, Derek; Majumdar, Arun K.; Kazemi, Alex A.

    2007-09-01

    Since the TWA flight 800 accident in July 1996, significant emphasis has been placed on fuel tank safety. The Federal Aviation Administration (FAA) has focused research to support two primary methods of fuel tank protection - ground-based and on-board - both involving fuel tank inerting. Ground-based fuel tank inerting involves some combination of fuel scrubbing and ullage washing with Nitrogen Enriched Air (NEA) while the airplane is on the ground (applicable to all or most operating transport airplanes). On-board fuel tank inerting involves ullage washing with OBIGGS (on-board inert gas generating system), a system that generates NEA during aircraft operations. An OBIGGS generally encompasses an air separation module (ASM) to generate NEA, a compressor, storage tanks, and a distribution system. Essential to the utilization of OBIGGS is an oxygen sensor that can operate inside the aircraft's ullage and assess the effectiveness of the inerting systems. OBIGGS can function economically by precisely knowing when to start and when to stop. Toward achieving these goals, InnoSense LLC is developing an all-optical fuel tank ullage sensor (FTUS) prototype for detecting oxygen in the ullage of an aircraft fuel tank in flight conditions. Data would be presented to show response time and wide dynamic range of the sensor in simulated flight conditions and fuel tank environment.

  4. Sensor-based material tagging system

    SciTech Connect

    Vercellotti, L.C.; Cox, R.W.; Ravas, R.J.; Schlotterer, J.C. . Science and Technology Center)

    1991-01-01

    Electronic identification tags are being developed for tracking material and personnel. In applying electronic identification tags to radioactive materials safeguards, it is important to measure attributes of the material to ensure that the tag remains with the material. The addition of a microcontroller with an on-board analog-to-digital converter to an electronic identification tag application-specific integrated-circuit has been demonstrated as means to provide the tag with sensor data. Each tag is assembled into a housing, which serves as a scale for measuring the weight of a paint-can-sized container and its contents. Temperature rise of the can above ambient is also measured, and a piezoelectric detector detects disturbances and immediately puts the tag into its alarm and beacon mode. Radiation measurement was also considered, but the background from nearby containers was found to be excessive. The sensor-based tagging system allows tracking of the material in cans as it is stored in vaults or is moved through the manufacturing process. The paper presents details of the sensor-based material tagging system and describes a demonstration system.

  5. Sensor-based material tagging system

    SciTech Connect

    Vercellotti, L.C.; Cox, R.W.; Ravas, R.J.; Schlotterer, J.C.

    1991-12-31

    Electronic identification tags are being developed for tracking material and personnel. In applying electronic identification tags to radioactive materials safeguards, it is important to measure attributes of the material to ensure that the tag remains with the material. The addition of a microcontroller with an on-board analog-to-digital converter to an electronic identification tag application-specific integrated-circuit has been demonstrated as means to provide the tag with sensor data. Each tag is assembled into a housing, which serves as a scale for measuring the weight of a paint-can-sized container and its contents. Temperature rise of the can above ambient is also measured, and a piezoelectric detector detects disturbances and immediately puts the tag into its alarm and beacon mode. Radiation measurement was also considered, but the background from nearby containers was found to be excessive. The sensor-based tagging system allows tracking of the material in cans as it is stored in vaults or is moved through the manufacturing process. The paper presents details of the sensor-based material tagging system and describes a demonstration system.

  6. Carbon Nanotube-Based Chemical Sensors.

    PubMed

    Meyyappan, M

    2016-04-01

    The need to sense gases and vapors arises in numerous scenarios in industrial, environmental, security and medical applications. Traditionally, this activity has utilized bulky instruments to obtain both qualitative and quantitative information on the constituents of the gas mixture. It is ideal to use sensors for this purpose since they are smaller in size and less expensive; however, their performance in the field must match that of established analytical instruments in order to gain acceptance. In this regard, nanomaterials as sensing media offer advantages in sensitivity, preparation of chip-based sensors and construction of electronic nose for selective detection of analytes of interest. This article provides a review of the use of carbon nanotubes in gas and vapor sensing. PMID:26959284

  7. Optical fiber-based fluorescent viscosity sensor

    NASA Astrophysics Data System (ADS)

    Haidekker, Mark A.; Akers, Walter J.; Fischer, Derek; Theodorakis, Emmanuel A.

    2006-09-01

    Molecular rotors are a unique group of viscosity-sensitive fluorescent probes. Several recent studies have shown their applicability as nonmechanical fluid viscosity sensors, particularly in biofluids containing proteins. To date, molecular rotors have had to be dissolved in the fluid for the measurement to be taken. We now show that molecular rotors may be covalently bound to a fiber-optic tip without loss of viscosity sensitivity. The optical fiber itself may be used as a light guide for emission light (external illumination of the tip) as well as for both emission and excitation light. Covalently bound molecular rotors exhibit a viscosity-dependent intensity increase similar to molecular rotors in solution. An optical fiber-based fluorescent viscosity sensor may be used in real-time measurement applications ranging from biomedical applications to the food industry.

  8. Dielectric sensors based on electromagnetic energy tunneling.

    PubMed

    Siddiqui, Omar; Kashanianfard, Mani; Ramahi, Omar

    2015-01-01

    We show that metallic wires embedded in narrow waveguide bends and channels demonstrate resonance behavior at specific frequencies. The electromagnetic energy at these resonances tunnels through the narrow waveguide channels with almost no propagation losses. Under the tunneling behavior, high-intensity electromagnetic fields are produced in the vicinity of the metallic wires. These intense field resonances can be exploited to build highly sensitive dielectric sensors. The sensor operation is explained with the help of full-wave simulations. A practical setup consisting of a 3D waveguide bend is presented to experimentally observe the tunneling phenomenon. The tunneling frequency is predicted by determining the input impedance minima through a variational formula based on the Green function of a probe-excited parallel plate waveguide. PMID:25835188

  9. Dielectric Sensors Based on Electromagnetic Energy Tunneling

    PubMed Central

    Siddiqui, Omar; Kashanianfard, Mani; Ramahi, Omar

    2015-01-01

    We show that metallic wires embedded in narrow waveguide bends and channels demonstrate resonance behavior at specific frequencies. The electromagnetic energy at these resonances tunnels through the narrow waveguide channels with almost no propagation losses. Under the tunneling behavior, high-intensity electromagnetic fields are produced in the vicinity of the metallic wires. These intense field resonances can be exploited to build highly sensitive dielectric sensors. The sensor operation is explained with the help of full-wave simulations. A practical setup consisting of a 3D waveguide bend is presented to experimentally observe the tunneling phenomenon. The tunneling frequency is predicted by determining the input impedance minima through a variational formula based on the Green function of a probe-excited parallel plate waveguide. PMID:25835188

  10. Virucidal activity of alcohol-based hand rub disinfectants.

    PubMed

    Iwasawa, Atsuo; Niwano, Yoshimi; Kohno, Masahiro; Ayaki, Masahiko

    2012-03-01

    We investigated the virucidal activity of commercially available alcohol-based hand rub products against coxsackievirus A7, B5, feline calicivirus F9, and human adenovirus type 3, type 7, type 8 using susceptible cell lines, Vero cells, CRFK cells, and A549 cells. Fifteen tested hand rub products were ethanol (EtOH) for disinfection (Japanese Pharmacopoeia Grade), two EtOH-based products, one povidone iode-containing product, one alkyldiaminoethylglycine hydrochloride-containing product, six benzalkonium chloride (BAK)-containing products, and four chlorohexidine gluconate (CHG)-containing products. Some active ingredients (BAK, benzetonium chloride, and CHG) were diluted with EtOH to make 0.5% and 0.2% solutions. Virus inactivation rates were calculated after contact with each hand rub product for 10 or 60 seconds. Of the hand rub products tested, only the povidone iode-based product showed antiviral activity superior to that of EtOH against all the strains. EtOH solutions of active ingredients (0.2% and 0.5%) also showed decreased antiviral activity. In conclusion, antiviral activity of all the commercially available alcohol-based hand rub products except that containing povidone idode was dependent on their active ingredients. The povidone idode-containing hand rub product kept its effectiveness even after the dilution with EtOH. Although alcohol-based hand rub products are convenient and suitable for the control of some microbes, they are not generally recommended for the control of viral infections. PMID:22451431

  11. Neural network based analysis for chemical sensor arrays

    SciTech Connect

    Hashem, S.; Keller, P.E.; Kouzes, R.T.; Kangas, L.J.

    1995-04-01

    Compact, portable systems capable of quickly identifying contaminants in the field are of great importance when monitoring the environment. In this paper, we examine the effectiveness of using artificial neural networks for real-time data analysis of a sensor array. Analyzing the sensor data in parallel may allow for rapid identification of contaminants in the field without requiring highly selective individual sensors. We use a prototype sensor array which consists of nine tin-oxide Taguchi-type sensors, a temperature sensor, and a humidity sensor. We illustrate that by using neural network based analysis of the sensor data, the selectivity of the sensor array may be significantly improved, especially when some (or all) the sensors are not highly selective.

  12. Microbiota-based treatments in alcoholic liver disease

    PubMed Central

    Sung, Hotaik; Kim, Seung Woo; Hong, Meegun; Suk, Ki Tae

    2016-01-01

    Gut microbiota plays a key role in the pathogenesis of alcoholic liver disease (ALD). Consumption of alcohol leads to increased gut permeability, small intestinal bacterial overgrowth, and enteric dysbiosis. These factors contribute to the increased translocation of microbial products to the liver via the portal tract. Subsequently, bacterial endotoxins such as lipopolysaccharide, in association with the Toll-like receptor 4 signaling pathway, induce a gamut of damaging immune responses in the hepatic milieu. Because of the close association between deleterious inflammation and ALD-induced microbiota imbalance, therapeutic approaches that seek to reestablish gut homeostasis should be considered in the treatment of alcoholic patients. To this end, a number of preliminary studies on probiotics have confirmed their effectiveness in suppressing proinflammatory cytokines and improving liver function in the context of ALD. In addition, there have been few studies linking the administration of prebiotics and antibiotics with reduction of alcohol-induced liver damage. Because these preliminary results are promising, large-scale randomized studies are warranted to elucidate the impact of these microbiota-based treatments on the gut flora and associated immune responses, in addition to exploring questions about optimal delivery. Finally, fecal microbiota transplant has been shown to be an effective method of modulating gut microbiota and deserve further investigation as a potential therapeutic option for ALD. PMID:27547010

  13. Microbiota-based treatments in alcoholic liver disease.

    PubMed

    Sung, Hotaik; Kim, Seung Woo; Hong, Meegun; Suk, Ki Tae

    2016-08-01

    Gut microbiota plays a key role in the pathogenesis of alcoholic liver disease (ALD). Consumption of alcohol leads to increased gut permeability, small intestinal bacterial overgrowth, and enteric dysbiosis. These factors contribute to the increased translocation of microbial products to the liver via the portal tract. Subsequently, bacterial endotoxins such as lipopolysaccharide, in association with the Toll-like receptor 4 signaling pathway, induce a gamut of damaging immune responses in the hepatic milieu. Because of the close association between deleterious inflammation and ALD-induced microbiota imbalance, therapeutic approaches that seek to reestablish gut homeostasis should be considered in the treatment of alcoholic patients. To this end, a number of preliminary studies on probiotics have confirmed their effectiveness in suppressing proinflammatory cytokines and improving liver function in the context of ALD. In addition, there have been few studies linking the administration of prebiotics and antibiotics with reduction of alcohol-induced liver damage. Because these preliminary results are promising, large-scale randomized studies are warranted to elucidate the impact of these microbiota-based treatments on the gut flora and associated immune responses, in addition to exploring questions about optimal delivery. Finally, fecal microbiota transplant has been shown to be an effective method of modulating gut microbiota and deserve further investigation as a potential therapeutic option for ALD. PMID:27547010

  14. Gait recognition based on Kinect sensor

    NASA Astrophysics Data System (ADS)

    Ahmed, Mohammed; Al-Jawad, Naseer; Sabir, Azhin T.

    2014-05-01

    This paper presents gait recognition based on human skeleton and trajectory of joint points captured by Microsoft Kinect sensor. In this paper Two sets of dynamic features are extracted during one gait cycle: the first is Horizontal Distance Features (HDF) that is based on the distances between (Ankles, knees, hands, shoulders), the second set is the Vertical Distance Features (VDF) that provide significant information of human gait extracted from the height to the ground of (hand, shoulder, and ankles) during one gait cycle. Extracting these two sets of feature are difficult and not accurate based on using traditional camera, therefore the Kinect sensor is used in this paper to determine the precise measurements. The two sets of feature are separately tested and then fused to create one feature vector. A database has been created in house to perform our experiments. This database consists of sixteen males and four females. For each individual, 10 videos have been recorded, each record includes in average two gait cycles. The Kinect sensor is used here to extract all the skeleton points, and these points are used to build up the feature vectors mentioned above. K-nearest neighbor is used as the classification method based on Cityblock distance function. Based on the experimental result the proposed method provides 56% as a recognition rate using HDF, while VDF provided 83.5% recognition accuracy. When fusing both of the HDF and VDF as one feature vector, the recognition rate increased to 92%, the experimental result shows that our method provides significant result compared to the existence methods.

  15. Adaptive sensing based on profiles for sensor systems.

    PubMed

    Ishida, Yoshiteru; Tokumitsu, Masahiro

    2009-01-01

    This paper proposes a profile-based sensing framework for adaptive sensor systems based on models that relate possibly heterogeneous sensor data and profiles generated by the models to detect events. With these concepts, three phases for building the sensor systems are extracted from two examples: a combustion control sensor system for an automobile engine, and a sensor system for home security. The three phases are: modeling, profiling, and managing trade-offs. Designing and building a sensor system involves mapping the signals to a model to achieve a given mission. PMID:22291516

  16. Rapid and mobile determination of alcoholic strength in wine, beer and spirits using a flow-through infrared sensor

    PubMed Central

    2010-01-01

    Background Ever since Gay-Lussac's time, the alcoholic strength by volume (% vol) has been determined by using densimetric measurements. The typical reference procedure involves distillation followed by pycnometry, which is comparably labour-intensive and therefore expensive. At present, infrared (IR) spectroscopy in combination with multivariate regression is widely applied as a screening procedure, which allows one to determine alcoholic strength in less than 2 min without any sample preparation. The disadvantage is the relatively large investment for Fourier transform (FT) IR or near-IR instruments, and the need for matrix-dependent calibration. In this study, we apply a much simpler device consisting of a patented multiple-beam infrared sensor in combination with a flow-through cell for automated alcohol analysis, which is available in a portable version that allows for on-site measurements. Results During method validation, the precision of the infrared sensor was found to be equal to or better than densimetric or FTIR methods. For example, the average repeatability, as determined in 6 different wine samples, was 0.05% vol and the relative standard deviation was below 0.2%. Accuracy was ensured by analyzing 260 different alcoholic beverages in comparison to densimetric or FTIR results. The correlation was linear over the entire range from alcohol-free beers up to high-proof spirits, and the results were in substantial agreement (R = 0.99981, p < 0.0001, RMSE = 0.279% vol). The applicability of the device was further proven for the analysis of wines during fermentation, and for the determination of unrecorded alcohol (i.e. non-commercial or illicit products). Conclusions The flow-through infrared device is much easier to handle than typical reference procedures, while time-consuming sample preparation steps such as distillation are not necessary. Therefore, the alcoholic strength can be economically and quickly controlled (requiring less than 60 s per sample

  17. Nanofiber Based Optical Sensors for Oxygen Determination

    NASA Astrophysics Data System (ADS)

    Xue, Ruipeng

    Oxygen sensors based on luminescent quenching of nanofibers were developed for measurement of both gaseous and dissolved oxygen concentrations. Electrospinning was used to fabricate "core-shell" fiber configurations in which oxygen-sensitive transition metal complexes are embedded into a polymer 'core' while a synthetic biocompatible polymer provides a protective 'shell.' Various matrix polymers and luminescent probes were studied in terms of their sensitivity, linear calibration, reversibility, response time, stability and probe-matrix interactions. Due to the small size and high surface area of these nanofibers, all samples showed rapid response and a highly linear response to oxygen. The sensitivity and photostability of the sensors were controlled by the identity of both the probe molecule and the polymer matrix. Such nanofiber sensor forms are particularly suitable in biological applications due to the fact that they do not consume oxygen, are biocompatible and biomimetic and can be easily incorporated into cell culture. Applications of these fibers in cancer cell research, wound healing, breath analysis and waste water treatment were explored.

  18. Photonic Crystal Sensors Based on Porous Silicon

    PubMed Central

    Pacholski, Claudia

    2013-01-01

    Porous silicon has been established as an excellent sensing platform for the optical detection of hazardous chemicals and biomolecular interactions such as DNA hybridization, antigen/antibody binding, and enzymatic reactions. Its porous nature provides a high surface area within a small volume, which can be easily controlled by changing the pore sizes. As the porosity and consequently the refractive index of an etched porous silicon layer depends on the electrochemial etching conditions photonic crystals composed of multilayered porous silicon films with well-resolved and narrow optical reflectivity features can easily be obtained. The prominent optical response of the photonic crystal decreases the detection limit and therefore increases the sensitivity of porous silicon sensors in comparison to sensors utilizing Fabry-Pérot based optical transduction. Development of porous silicon photonic crystal sensors which allow for the detection of analytes by the naked eye using a simple color change or the fabrication of stacked porous silicon photonic crystals showing two distinct optical features which can be utilized for the discrimination of analytes emphasize its high application potential. PMID:23571671

  19. Biomimetic, polymer-based microcantilever infrared sensors

    NASA Astrophysics Data System (ADS)

    Mueller, Michael Thomas

    This dissertation describes the initial development of a polymer-based, microcantilever infrared sensor. The development of the sensor is bio-inspired and based upon the long-range infrared sensor found in the pyrophilous jewel beetle Melanophila acuminata, which is able to seek out forest fires from more than 50 km away. Based on several proposed models of the infrared detector found in Melanophila acuminata, as well as published in vivo experiments, the feasibility of polymer-based infrared thermal sensors was explored and developed. Polymer materials were chosen due to their high absorptivity in the infrared range due to vibrational resonance modes characteristic of their organic bonds. Polymeric materials investigated in the course of this work include the polysaccharide and biomaterial chitin, its deacetylated derivative, chitosan, and the work-horse polymer of the semiconductor industry, novolak-resin-based photoresist. Chitin and chitosan are particularly noteworthy polymers for exploration in infrared detection due to their natural absorbance of infrared radiation near the 3 mum and 10 mum bands, which are important for the detection of the temperatures of warm engines and human body temperature, respectively. Because only limited work (primarily focused on electrodeposition) has been focused on the microscale patterning of chitosan, a photolithography process for chitosan and chitin was developed to allow the integration of the material into a variety of microelectromechanical systems processes. In addition to optical/infrared sensing, this process has a variety of potential applications in tissue engineering, protein engineering, and lab-on-a-chip devices. To demonstrate these areas of use, surface functionalization was demonstrated using bioconjugation to attach a protein to a patterned chitosan surface. Thin films of chitosan and chitin were characterized using laser profilometry to identify the effect of temperature on the film stress, and contact

  20. SAW ethanol gas sensors based on cryptophane-A sensitive film

    NASA Astrophysics Data System (ADS)

    Sun, Ping; Jiang, Yadong; Xie, Guangzhong; Du, Xiaosong

    2010-10-01

    Surface acoustic wave (SAW) devices have been widely used for various chemical sensing applications because the sensor signal can be detected by simple and inexpensive electronics. The interactions between target analyte and the sensor surface cause changes in the mechanical, electrical, dielectric properties of the sensing coating deposited onto acoustic transducer. The changes in these properties will lead to changes in the velocity and amplitude of wave modes, which can be measured by frequency and insertion loss (IL) changes when the acoustic element is realized as a delay line or resonator. Among the different sensing coatings, the supermolecules are of considerable interest because the host molecules can be thought as original receptors allowing a specific recognition of guest molecules based on "key-lock" system. In this paper, SAW ethanol gas sensors that utilize the supermolecule of cryptophane-A as sensitive layer have been studied. We synthesized cryptophane-A from vanillyl alcohol using a double trimerisation method and deposited it on the SAW devices to fabricate cryptophane-A based SAW gas sensors. The SAW frequency and insertion loss (IL) were measured using a network analyzer. The frequency shift as the response of the cryptophane-A based SAW sensors to different concentration ethanol was measured at room temperature. It is found that the cryptophane-A based SAW sensor has high sensitivity and good reproductivity to ethanol. The frequency response increased linearly with the concentration of the ethanol.

  1. Advances and trends in ionophore-based chemical sensors

    NASA Astrophysics Data System (ADS)

    Mikhelson, K. N.; Peshkova, M. A.

    2015-06-01

    The recent advances in the theory and practice of potentiometric, conductometric and optical sensors based on ionophores are critically reviewed. The role of the heterogeneity of the sensor/sample systems is emphasized, and it is shown that due to this heterogeneity such sensors respond to the analyte activities rather than to concentrations. The basics of the origin of the response of all three kinds of ionophore-based sensors are briefly described. The use of novel sensor materials, new preparation and application techniques of the sensors as well as advances in theoretical treatment of the sensor response are analyzed using literature sources published mainly from 2012 to 2014. The basic achievements made in the past are also addressed when necessary for better understanding of the trends in the field of ionophore-based sensors. The bibliography includes 295 references.

  2. A large area tactile sensor patch based on commercial force sensors.

    PubMed

    Vidal-Verdú, Fernando; Barquero, Maria Jose; Castellanos-Ramos, Julián; Navas-González, Rafael; Sánchez, Jose Antonio; Serón, Javier; García-Cerezo, Alfonso

    2011-01-01

    This paper reports the design of a tactile sensor patch to cover large areas of robots and machines that interact with human beings. Many devices have been proposed to meet such a demand. These realizations are mostly custom-built or developed in the lab. The sensor of this paper is implemented with commercial force sensors. This has the benefit of a more foreseeable response of the sensor if its behavior is understood as the aggregation of readings from all the individual force sensors in the array. A few reported large area tactile sensors are also based on commercial sensors. However, the one in this paper is the first of this kind based on the use of polymeric commercial force sensing resistors (FSR) as unit elements of the array or tactels, which results in a robust sensor. The paper discusses design issues related to some necessary modifications of the force sensor, its assembly in an array, and the signal conditioning. The patch has 16 × 9 force sensors mounted on a flexible printed circuit board with a spatial resolution of 18.5 mm. The force range of a tactel is 6 N and its sensitivity is 0.6 V/N. The array is read at a rate of 78 frames per second. Finally, two simple application examples are also carried out with the sensor mounted on the forearm of a rescue robot that communicates with the sensor through a CAN bus. PMID:22163910

  3. A Large Area Tactile Sensor Patch Based on Commercial Force Sensors

    PubMed Central

    Vidal-Verdú, Fernando; Barquero, Maria Jose; Castellanos-Ramos, Julián; Navas-González, Rafael; Sánchez, Jose Antonio; Serón, Javier; García-Cerezo, Alfonso

    2011-01-01

    This paper reports the design of a tactile sensor patch to cover large areas of robots and machines that interact with human beings. Many devices have been proposed to meet such a demand. These realizations are mostly custom-built or developed in the lab. The sensor of this paper is implemented with commercial force sensors. This has the benefit of a more foreseeable response of the sensor if its behavior is understood as the aggregation of readings from all the individual force sensors in the array. A few reported large area tactile sensors are also based on commercial sensors. However, the one in this paper is the first of this kind based on the use of polymeric commercial force sensing resistors (FSR) as unit elements of the array or tactels, which results in a robust sensor. The paper discusses design issues related to some necessary modifications of the force sensor, its assembly in an array, and the signal conditioning. The patch has 16 × 9 force sensors mounted on a flexible printed circuit board with a spatial resolution of 18.5 mm. The force range of a tactel is 6 N and its sensitivity is 0.6 V/N. The array is read at a rate of 78 frames per second. Finally, two simple application examples are also carried out with the sensor mounted on the forearm of a rescue robot that communicates with the sensor through a CAN bus. PMID:22163910

  4. Research of marine sensor web based on SOA and EDA

    NASA Astrophysics Data System (ADS)

    Jiang, Yongguo; Dou, Jinfeng; Guo, Zhongwen; Hu, Keyong

    2015-04-01

    A great deal of ocean sensor observation data exists, for a wide range of marine disciplines, derived from in situ and remote observing platforms, in real-time, near-real-time and delayed mode. Ocean monitoring is routinely completed using sensors and instruments. Standardization is the key requirement for exchanging information about ocean sensors and sensor data and for comparing and combining information from different sensor networks. One or more sensors are often physically integrated into a single ocean `instrument' device, which often brings in many challenges related to diverse sensor data formats, parameters units, different spatiotemporal resolution, application domains, data quality and sensors protocols. To face these challenges requires the standardization efforts aiming at facilitating the so-called Sensor Web, which making it easy to provide public access to sensor data and metadata information. In this paper, a Marine Sensor Web, based on SOA and EDA and integrating the MBARI's PUCK protocol, IEEE 1451 and OGC SWE 2.0, is illustrated with a five-layer architecture. The Web Service layer and Event Process layer are illustrated in detail with an actual example. The demo study has demonstrated that a standard-based system can be built to access sensors and marine instruments distributed globally using common Web browsers for monitoring the environment and oceanic conditions besides marine sensor data on the Web, this framework of Marine Sensor Web can also play an important role in many other domains' information integration.

  5. Nanowire-based electromechanical biomimetic sensor

    NASA Astrophysics Data System (ADS)

    Tonisch, K.; Cimalla, V.; Will, F.; Weise, F.; Stubenrauch, M.; Albrecht, A.; Hoffmann, M.; Ambacher, O.

    2007-03-01

    We propose the development of a basic module for a novel nanowire-based nanoelectromechanical device, which will require the mechanical coupling of nanowires to an AlGaN/GaN heterostructure containing a polarization-induced 2D electron gas. The deflection of freestanding nanowires in a streaming liquid causes an additional strain in the AlGaN barrier which leads to a change in the resistance of the 2D electron gas. The basic structure, underlying theoretical considerations and first steps towards the realization of this new sensor concept are presented.

  6. Waveguide-based optical chemical sensor

    DOEpatents

    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.

  7. Nanotechnology-based Sensors for Environmental Monitoring

    NASA Astrophysics Data System (ADS)

    Mickelson, Willi

    2010-03-01

    COINS mission is to inspire and realize applications directed towards sensing of environmental conditions using nano-mechanical technology, integrated with suitable societal implications studies and educational, outreach, and knowledge transfer programs. Specifically, the technical focus of COINS is to develop the means for realizing its two major technology applications -- personal and community-based environmental monitoring (PACMON) and tagging tracking and locating (TTL). These platforms combine technologies of molecular recognition and signal transduction, energy harvesting and conversion, efficient signal processing and wireless communications, and mobility. In this talk, I will give an overview of some of the recent advances in our environmental monitoring sensor development.

  8. UV sensors based on liquid crystals mixtures

    NASA Astrophysics Data System (ADS)

    Chanishvili, Andro; Petriashvili, Gia; Chilaya, Guram; Barberi, Riccardo; De Santo, Maria P.; Matranga, Mario A.; Ciuchi, F.

    2006-04-01

    The Erythemal Response Spectrum is a scientific expression that describes the sensitivity of the skin to the ultraviolet radiation. The skin sensitivity strongly depends on the UV wavelength: a long exposition to UV radiation causes erythema once a threshold dose has been exceeded. In the past years several devices have been developed in order to monitor the UV exposure, most of them are based on inorganic materials that are able to mimic the human skin behaviour under UV radiation. We present a new device based on liquid crystals technology. The sensor is based on a liquid crystalline mixture that absorbs photons at UV wavelength and emits them at a longer one. This system presents several innovative features: the absorption range of the mixture can be varied to be sensitive to different wavelengths, the luminescence intensity can be tuned, the system can be implemented on flexible devices.

  9. Sensor Saturation Compensated Smoothing Algorithm for Inertial Sensor Based Motion Tracking

    PubMed Central

    Dang, Quoc Khanh; Suh, Young Soo

    2014-01-01

    In this paper, a smoothing algorithm for compensating inertial sensor saturation is proposed. The sensor saturation happens when a sensor measures a value that is larger than its dynamic range. This can lead to a considerable accumulated error. To compensate the lost information in saturated sensor data, we propose a smoothing algorithm in which the saturation compensation is formulated as an optimization problem. Based on a standard smoothing algorithm with zero velocity intervals, two saturation estimation methods were proposed. Simulation and experiments prove that the proposed methods are effective in compensating the sensor saturation. PMID:24806740

  10. Gene-based and pathway-based genome-wide association study of alcohol dependence

    PubMed Central

    ZUO, Lingjun; ZHANG, Clarence K.; SAYWARD, Frederick G.; CHEUNG, Kei-Hoi; WANG, Kesheng; KRYSTAL, John H.; ZHAO, Hongyu; LUO, Xingguang

    2015-01-01

    Background The organization of risk genes within signaling pathways may provide clues about the converging neurobiological effects of risk genes for alcohol dependence. Aim Identify risk genes and risk gene pathways for alcohol dependence. Methods We conducted a pathway-based genome-wide association study (GWAS) of alcohol dependence using a gene-set-rich analytic approach. Approximately one million genetic markers were tested in the discovery sample which included 1409 European-American (EA) alcohol dependent individuals and 1518 EA healthy comparison subjects. An additional 681 African-American (AA) cases and 508 AA healthy subjects served as the replication sample. Results We identified several genome-wide replicable risk genes and risk pathways that were significantly associated with alcohol dependence. After applying the Bonferroni correction for multiple testing, the ‘cellextracellular matrix interactions’ pathway (p<2.0E-4 in EAs) and the PXN gene (which encodes paxillin) (p=3.9E-7 in EAs) within this pathway were the most promising risk factors for alcohol dependence. There were also two nominally replicable pathways enriched in alcohol dependence-related genes in both EAs (0.015≤p≤0.035) and AAs (0.025≤p≤0.050): the ‘Na+/Cl- dependent neurotransmitter transporters’ pathway and the ‘other glycan degradation’ pathway. Conclusion These findings provide new evidence highlighting several genes and biological signaling processes that may be related to the risk for alcohol dependence. PMID:26120261

  11. Gas Sensors Based on Conducting Polymers

    PubMed Central

    Bai, Hua; Shi, Gaoquan

    2007-01-01

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

  12. Sensors Based on Spectroscopy of Guided Waves

    NASA Astrophysics Data System (ADS)

    Homola, Jiří

    The last two decades have witnessed remarkable progress in the develpment of affinity biosensors and their applications in areas such as environmental protection, biotechnology, medical diagnostics, drug screening, food safety, and security. An affinity biosensor consists of a transducer and a biological recognition element which is able to interact with a selected analyte. Various optical methods have been exploited in biosensors including fluorescence spectroscopy, interferometry (reflectometric white light interferometry, modal interferometry in optical waveguide structures), and spectroscopy of guided modes of optical waveguides. Optical biosensors based on spectroscopy of guided modes of optical waveguides - grating coupler, resonant mirror, and surface plasmon resonance (SPR) - rely on the measurement of binding-induced refractive index changes and thus are label-free technologies. This paper reviews fundamentals of optical sensors based on spectroscopy of guided modes of optical waveguides and their applications.

  13. Highly selective gas sensor arrays based on thermally reduced graphene oxide

    NASA Astrophysics Data System (ADS)

    Lipatov, Alexey; Varezhnikov, Alexey; Wilson, Peter; Sysoev, Victor; Kolmakov, Andrei; Sinitskii, Alexander

    2013-05-01

    The electrical properties of reduced graphene oxide (rGO) have been previously shown to be very sensitive to surface adsorbates, thus making rGO a very promising platform for highly sensitive gas sensors. However, poor selectivity of rGO-based gas sensors remains a major problem for their practical use. In this paper, we address the selectivity problem by employing an array of rGO-based integrated sensors instead of focusing on the performance of a single sensing element. Each rGO-based device in such an array has a unique sensor response due to the irregular structure of rGO films at different levels of organization, ranging from nanoscale to macroscale. The resulting rGO-based gas sensing system could reliably recognize analytes of nearly the same chemical nature. In our experiments rGO-based sensor arrays demonstrated a high selectivity that was sufficient to discriminate between different alcohols, such as methanol, ethanol and isopropanol, at a 100% success rate. We also discuss a possible sensing mechanism that provides the basis for analyte differentiation.

  14. Single conducting polymer nanowire based conductometric sensors

    NASA Astrophysics Data System (ADS)

    Bangar, Mangesh Ashok

    The detection of toxic chemicals, gases or biological agents at very low concentrations with high sensitivity and selectivity has been subject of immense interest. Sensors employing electrical signal readout as transduction mechanism offer easy, label-free detection of target analyte in real-time. Traditional thin film sensors inherently suffered through loss of sensitivity due to current shunting across the charge depleted/added region upon analyte binding to the sensor surface, due to their large cross sectional area. This limitation was overcome by use of nanostructure such as nanowire/tube as transducer where current shunting during sensing was almost eliminated. Due to their benign chemical/electrochemical fabrication route along with excellent electrical properties and biocompatibility, conducting polymers offer cost-effective alternative over other nanostructures. Biggest obstacle in using these nanostructures is lack of easy, scalable and cost-effective way of assembling these nanostructures on prefabricated micropatterns for device fabrication. In this dissertation, three different approaches have been taken to fabricate individual or array of single conducting polymer (and metal) nanowire based devices and using polymer by itself or after functionalization with appropriate recognition molecule they have been applied for gas and biochemical detection. In the first approach electrochemical fabrication of multisegmented nanowires with middle functional Ppy segment along with ferromagnetic nickel (Ni) and end gold segments for better electrical contact was studied. This multi-layered nanowires were used along with ferromagnetic contact electrode for controlled magnetic assembly of nanowires into devices and were used for ammonia gas sensing. The second approach uses conducting polymer, polypyrrole (Ppy) nanowires using simple electrophoretic alignment and maskless electrodeposition to anchor nanowire which were further functionalized with antibodies against

  15. Effects of a Stage-based Alcohol Preventive Intervention for Inner-City Youth.

    ERIC Educational Resources Information Center

    Werch, Chudley E.; Carlson, Joan M.; Owen, Deborah M.; DiClemente, Carlo C.; Carbonari, Joseph P.

    2001-01-01

    Examines first year outcomes of an alcohol preventive intervention within inner-city middle schools. Results reveal that significantly fewer neighborhood intervention students initiated alcohol use compared to control students. Suggests that a brief, stage-based preventive intervention may result in significant reductions in alcohol initiation and…

  16. Evaluation of an Elementary School-Based Alcohol Misuse Prevention Program.

    ERIC Educational Resources Information Center

    Shope, Jean T.; And Others

    The Alcohol Misuse Prevention Study (AMPS) presented an alcohol education program to fifth and sixth grade students based on social learning theory. The AMPS program introduced students to the concept of social pressure (especially peer pressure) to misuse alcohol and to strategies to effectively counter such pressure. The program was evaluated in…

  17. Habitual Alcohol Seeking: Neural Bases and Possible Relations to Alcohol Use Disorders.

    PubMed

    Corbit, Laura H; Janak, Patricia H

    2016-07-01

    Loss of flexible control over alcohol use may contribute to the development of alcohol use disorders. An increased contribution of response habits to alcohol-related behaviors may help explain this loss of control. Focusing on data from outcome devaluation and Pavlovian-instrumental transfer procedures, we review evidence for loss of goal-directed control over alcohol seeking and consumption drawing from both preclinical findings and clinical data where they exist. Over the course of extended alcohol self-administration and exposure, the performance of alcohol-seeking responses becomes less sensitive to reduction in the value of alcohol and more vulnerable to the influences of alcohol-predictive stimuli. These behavioral changes are accompanied by a shift in the corticostriatal circuits that control responding from circuits centered on the dorsomedial to those centered on the dorsolateral striatum. These changes in behavioral and neural control could help explain failures to abstain from alcohol despite intention to do so. Understanding and ultimately ameliorating these changes will aid development of more effective treatment interventions. PMID:27223341

  18. Optical Sensors Based on Plastic Fibers

    PubMed Central

    Bilro, Lúcia; Alberto, Nélia; Pinto, João L.; Nogueira, Rogério

    2012-01-01

    The recent advances of polymer technology allowed the introduction of plastic optical fiber in sensor design. The advantages of optical metrology with plastic optical fiber have attracted the attention of the scientific community, as they allow the development of low-cost or cost competitive systems compared with conventional technologies. In this paper, the current state of the art of plastic optical fiber technology will be reviewed, namely its main characteristics and sensing advantages. Several measurement techniques will be described, with a strong focus on interrogation approaches based on intensity variation in transmission and reflection. The potential applications involving structural health monitoring, medicine, environment and the biological and chemical area are also presented. PMID:23112707

  19. Carbon-Nanotube-Based Chemical Gas Sensor

    NASA Technical Reports Server (NTRS)

    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.

  20. Protein Sensors Based on Optical Ring Resonators

    NASA Technical Reports Server (NTRS)

    Lin, Ying; Ksendzov, Alexander

    2006-01-01

    Prototype transducers based on integrated optical ring resonators have been demonstrated to be useful for detecting the protein avidin in extremely dilute solutions. In an experiment, one of the transducers proved to be capable of indicating the presence of avidin at a concentration of as little as 300 pM in a buffer solution a detection sensitivity comparable to that achievable by previously reported protein-detection techniques. These transducers are serving as models for the further development of integrated-optics sensors for detecting small quantities of other proteins and protein-like substances. The basic principle of these transducers was described in Chemical Sensors Based on Optical Ring Resonators (NPO-40601), NASA Tech Briefs, Vol. 29, No. 10 (October 2005), page 32. The differences between the present transducers and the ones described in the cited prior article lie in details of implementation of the basic principle. As before, the resonator in a transducer of the present type is a closed-circuit dielectric optical waveguide. The outermost layer of this waveguide, analogous to the optical cladding layer on an optical fiber, consists of a layer comprising sublayers having indices of refraction lower than that of the waveguide core. The outermost sublayer absorbs the chemical of interest (in this case, avidin). The index of refraction of the outermost sublayer changes with the concentration of absorbed avidin. The resonator is designed to operate with relatively strong evanescent-wave coupling between the outer sublayer and the electromagnetic field propagating along the waveguide core. By virtue of this coupling, the chemically induced change in the index of refraction of the outermost sublayer causes a measurable change in the spectrum of the resonator output.

  1. Sensor-based demand controlled ventilation

    SciTech Connect

    De Almeida, A.T.; Fisk, W.J.

    1997-07-01

    In most buildings, occupancy and indoor pollutant emission rates vary with time. With sensor-based demand-controlled ventilation (SBDCV), the rate of ventilation (i.e., rate of outside air supply) also varies with time to compensate for the changes in pollutant generation. In other words, SBDCV involves the application of sensing, feedback and control to modulate ventilation. Compared to ventilation without feedback, SBDCV offers two potential advantages: (1) better control of indoor pollutant concentrations; and (2) lower energy use and peak energy demand. SBDCV has the potential to improve indoor air quality by increasing the rate of ventilation when indoor pollutant generation rates are high and occupants are present. SBDCV can also save energy by decreasing the rate of ventilation when indoor pollutant generation rates are low or occupants are absent. After providing background information on indoor air quality and ventilation, this report provides a relatively comprehensive discussion of SBDCV. Topics covered in the report include basic principles of SBDCV, sensor technologies, technologies for controlling air flow rates, case studies of SBDCV, application of SBDCV to laboratory buildings, and research needs. SBDCV appears to be an increasingly attractive technology option. Based on the review of literature and theoretical considerations, the application of SBDCV has the potential to be cost-effective in applications with the following characteristics: (a) a single or small number of dominant pollutants, so that ventilation sufficient to control the concentration of the dominant pollutants provides effective control of all other pollutants; (b) large buildings or rooms with unpredictable temporally variable occupancy or pollutant emission; and (c) climates with high heating or cooling loads or locations with expensive energy.

  2. Vehicle Fault Diagnose Based on Smart Sensor

    NASA Astrophysics Data System (ADS)

    Zhining, Li; Peng, Wang; Jianmin, Mei; Jianwei, Li; Fei, Teng

    In the vehicle's traditional fault diagnose system, we usually use a computer system with a A/D card and with many sensors connected to it. The disadvantage of this system is that these sensor can hardly be shared with control system and other systems, there are too many connect lines and the electro magnetic compatibility(EMC) will be affected. In this paper, smart speed sensor, smart acoustic press sensor, smart oil press sensor, smart acceleration sensor and smart order tracking sensor were designed to solve this problem. With the CAN BUS these smart sensors, fault diagnose computer and other computer could be connected together to establish a network system which can monitor and control the vehicle's diesel and other system without any duplicate sensor. The hard and soft ware of the smart sensor system was introduced, the oil press, vibration and acoustic signal are resampled by constant angle increment to eliminate the influence of the rotate speed. After the resample, the signal in every working cycle could be averaged in angle domain and do other analysis like order spectrum.

  3. Neural network-based sensor signal accelerator.

    SciTech Connect

    Vogt, M. C.

    2000-10-16

    A strategy has been developed to computationally accelerate the response time of a generic electronic sensor. The strategy can be deployed as an algorithm in a control system or as a physical interface (on an embedded microcontroller) between a slower responding external sensor and a higher-speed control system. Optional code implementations are available to adjust algorithm performance when computational capability is limited. In one option, the actual sensor signal can be sampled at the slower rate with adaptive linear neural networks predicting the sensor's future output and interpolating intermediate synthetic output values. In another option, a synchronized collection of predictors sequentially controls the corresponding synthetic output voltage. Error is adaptively corrected in both options. The core strategy has been demonstrated with automotive oxygen sensor data. A prototype interface device is under construction. The response speed increase afforded by this strategy could greatly offset the cost of developing a replacement sensor with a faster physical response time.

  4. Do flexible alcohol trading hours reduce violence? A theory-based natural experiment in alcohol policy.

    PubMed

    Humphreys, David K; Eisner, Manuel P

    2014-02-01

    Alcohol-related violence is a pressing public health concern. In 2005, the government of England and Wales took a controversial approach to preventing violence by removing restrictions on opening hours for alcohol outlets, thus increasing the availability of alcohol. The policy aimed to remove fixed closing times, which it claimed was contributing to urban violence occurring at peak closing times. It proposed to reduce violence and disorder by installing systems of 'staggered closing times'. This policy was criticised for overlooking established public health principles prioritising the control of alcohol availability in the prevention of alcohol-related harm. In this study, we treated the removal of trading hour restrictions as a natural experiment to test competing theoretical principles about the relationship between alcohol availability and violence. Our study took place in the City of Manchester over a four-year period 2004-2008. Detailed trading records for over 600 alcohol outlets were obtained, as were police records for all violent incidents. We found considerable variation in the implementation of extended trading hours across the city, which affected area-level exposure of changes in alcohol availability and staggered closing times. To isolate the effect of these changes on violence, we performed a dose-response analysis to examine whether improved staggering of closing hours (or increased alcohol availability) was associated with decreases in violence. We found no evidence to support the government-proposed hypothesis that staggered closing reduces violence. We also found no support for the alternative hypothesis; that increase alcohol availability would result in increased violence. This study provides an example of how better evidence can be generated from natural experiments by placing added emphasis on theory, causal mechanisms and implementation science. PMID:24565135

  5. Smart pavement sensor based on thermoelectricity power

    NASA Astrophysics Data System (ADS)

    Yu, Xiong; Zhang, Bin; Tao, Junliang; Liu, Zhen

    2010-04-01

    The aging infrastructure requires a proactive strategy to ensure their functionality and performance. Innovative sensors are needed to develop infrastructures that are intelligent and adaptive. A power supply strategy is among the crucial components to reduce the instrument cost and to ensure the long term function of these embedded sensors. This paper introduces the results of a preliminary study on using thermo-electricity generation to power sensors. This presents an innovative strategy for long term monitoring of pavement performance.

  6. Development of GaN-based micro chemical sensor nodes

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

  7. Chemical Sensors Based on Optical Ring Resonators

    NASA Technical Reports Server (NTRS)

    Homer, Margie; Manfreda, Allison; Mansour, Kamjou; Lin, Ying; Ksendzov, Alexander

    2005-01-01

    Chemical sensors based on optical ring resonators are undergoing development. A ring resonator according to this concept is a closed-circuit dielectric optical waveguide. The outermost layer of this waveguide, analogous to the optical cladding layer on an optical fiber, is a made of a polymer that (1) has an index of refraction lower than that of the waveguide core and (2) absorbs chemicals from the surrounding air. The index of refraction of the polymer changes with the concentration of absorbed chemical( s). The resonator is designed to operate with relatively strong evanescent-wave coupling between the outer polymer layer and the electromagnetic field propagating along the waveguide core. By virtue of this coupling, the chemically induced change in index of refraction of the polymer causes a measurable shift in the resonance peaks of the ring. In a prototype that has been used to demonstrate the feasibility of this sensor concept, the ring resonator is a dielectric optical waveguide laid out along a closed path resembling a racetrack (see Figure 1). The prototype was fabricated on a silicon substrate by use of standard techniques of thermal oxidation, chemical vapor deposition, photolithography, etching, and spin coating. The prototype resonator waveguide features an inner cladding of SiO2, a core of SixNy, and a chemical-sensing outer cladding of ethyl cellulose. In addition to the ring Chemical sensors based on optical ring resonators are undergoing development. A ring resonator according to this concept is a closed-circuit dielectric optical waveguide. The outermost layer of this waveguide, analogous to the optical cladding layer on an optical fiber, is a made of a polymer that (1) has an index of refraction lower than that of the waveguide core and (2) absorbs chemicals from the surrounding air. The index of refraction of the polymer changes with the concentration of absorbed chemical( s). The resonator is designed to operate with relatively strong

  8. Biotoxin detection using cell-based sensors.

    PubMed

    Banerjee, Pratik; Kintzios, Spyridon; Prabhakarpandian, Balabhaskar

    2013-12-01

    Cell-based biosensors (CBBs) utilize the principles of cell-based assays (CBAs) by employing living cells for detection of different analytes from environment, food, clinical, or other sources. For toxin detection, CBBs are emerging as unique alternatives to other analytical methods. The main advantage of using CBBs for probing biotoxins and toxic agents is that CBBs respond to the toxic exposures in the manner related to actual physiologic responses of the vulnerable subjects. The results obtained from CBBs are based on the toxin-cell interactions, and therefore, reveal functional information (such as mode of action, toxic potency, bioavailability, target tissue or organ, etc.) about the toxin. CBBs incorporate both prokaryotic (bacteria) and eukaryotic (yeast, invertebrate and vertebrate) cells. To create CBB devices, living cells are directly integrated onto the biosensor platform. The sensors report the cellular responses upon exposures to toxins and the resulting cellular signals are transduced by secondary transducers generating optical or electrical signals outputs followed by appropriate read-outs. Examples of the layout and operation of cellular biosensors for detection of selected biotoxins are summarized. PMID:24335754

  9. Mammalian Cell-Based Sensor System

    NASA Astrophysics Data System (ADS)

    Banerjee, Pratik; Franz, Briana; Bhunia, Arun K.

    Use of living cells or cellular components in biosensors is receiving increased attention and opens a whole new area of functional diagnostics. The term "mammalian cell-based biosensor" is designated to biosensors utilizing mammalian cells as the biorecognition element. Cell-based assays, such as high-throughput screening (HTS) or cytotoxicity testing, have already emerged as dependable and promising approaches to measure the functionality or toxicity of a compound (in case of HTS); or to probe the presence of pathogenic or toxigenic entities in clinical, environmental, or food samples. External stimuli or changes in cellular microenvironment sometimes perturb the "normal" physiological activities of mammalian cells, thus allowing CBBs to screen, monitor, and measure the analyte-induced changes. The advantage of CBBs is that they can report the presence or absence of active components, such as live pathogens or active toxins. In some cases, mammalian cells or plasma membranes are used as electrical capacitors and cell-cell and cell-substrate contact is measured via conductivity or electrical impedance. In addition, cytopathogenicity or cytotoxicity induced by pathogens or toxins resulting in apoptosis or necrosis could be measured via optical devices using fluorescence or luminescence. This chapter focuses mainly on the type and applications of different mammalian cell-based sensor systems.

  10. Biotoxin Detection Using Cell-Based Sensors

    PubMed Central

    Banerjee, Pratik; Kintzios, Spyridon; Prabhakarpandian, Balabhaskar

    2013-01-01

    Cell-based biosensors (CBBs) utilize the principles of cell-based assays (CBAs) by employing living cells for detection of different analytes from environment, food, clinical, or other sources. For toxin detection, CBBs are emerging as unique alternatives to other analytical methods. The main advantage of using CBBs for probing biotoxins and toxic agents is that CBBs respond to the toxic exposures in the manner related to actual physiologic responses of the vulnerable subjects. The results obtained from CBBs are based on the toxin-cell interactions, and therefore, reveal functional information (such as mode of action, toxic potency, bioavailability, target tissue or organ, etc.) about the toxin. CBBs incorporate both prokaryotic (bacteria) and eukaryotic (yeast, invertebrate and vertebrate) cells. To create CBB devices, living cells are directly integrated onto the biosensor platform. The sensors report the cellular responses upon exposures to toxins and the resulting cellular signals are transduced by secondary transducers generating optical or electrical signals outputs followed by appropriate read-outs. Examples of the layout and operation of cellular biosensors for detection of selected biotoxins are summarized. PMID:24335754

  11. Polygenic risk for alcohol dependence associates with alcohol consumption, cognitive function and social deprivation in a population-based cohort.

    PubMed

    Clarke, Toni-Kim; Smith, Andrew H; Gelernter, Joel; Kranzler, Henry R; Farrer, Lindsay A; Hall, Lynsey S; Fernandez-Pujals, Ana M; MacIntyre, Donald J; Smith, Blair H; Hocking, Lynne J; Padmanabhan, Sandosh; Hayward, Caroline; Thomson, Pippa A; Porteous, David J; Deary, Ian J; McIntosh, Andrew M

    2016-03-01

    Alcohol dependence is frequently co-morbid with cognitive impairment. The relationship between these traits is complex as cognitive dysfunction may arise as a consequence of heavy drinking or exist prior to the onset of dependence. In the present study, we tested the genetic overlap between cognitive abilities and alcohol dependence using polygenic risk scores (PGRS). We created two independent PGRS derived from two recent genome-wide association studies (GWAS) of alcohol dependence (SAGE GWAS: n = 2750; Yale-Penn GWAS: n = 2377) in a population-based cohort, Generation Scotland: Scottish Family Health Study (GS:SFHS) (n = 9863). Data on alcohol consumption and four tests of cognitive function [Mill Hill Vocabulary (MHV), digit symbol coding, phonemic verbal fluency (VF) and logical memory] were available. PGRS for alcohol dependence were negatively associated with two measures of cognitive function: MHV (SAGE: P = 0.009, β = -0.027; Yale-Penn: P = 0.001, β = -0.034) and VF (SAGE: P = 0.0008, β = -0.036; Yale-Penn: P = 0.00005, β = -0.044). VF remained robustly associated after adjustment for education and social deprivation; however, the association with MHV was substantially attenuated. Shared genetic variants may account for some of the phenotypic association between cognitive ability and alcohol dependence. A significant negative association between PGRS and social deprivation was found (SAGE: P = 5.2 × 10(-7) , β = -0.054; Yale-Penn: P = 0.000012, β = -0.047). Individuals living in socially deprived regions were found to carry more alcohol dependence risk alleles which may contribute to the increased prevalence of problem drinking in regions of deprivation. Future work to identify genes which affect both cognitive impairment and alcohol dependence will help elucidate biological processes common to both disorders. PMID:25865819

  12. Force/torque and tactile sensors for sensor-based manipulator control

    NASA Technical Reports Server (NTRS)

    Vanbrussel, H.; Belieen, H.; Bao, Chao-Ying

    1989-01-01

    The autonomy of manipulators, in space and in industrial environments, can be dramatically enhanced by the use of force/torque and tactile sensors. The development and future use of a six-component force/torque sensor for the Hermes Robot Arm (HERA) Basic End-Effector (BEE) is discussed. Then a multifunctional gripper system based on tactile sensors is described. The basic transducing element of the sensor is a sheet of pressure-sensitive polymer. Tactile image processing algorithms for slip detection, object position estimation, and object recognition are described.

  13. Metal Ion Sensors Based on DNAzymes and Related DNA Molecules

    NASA Astrophysics Data System (ADS)

    Zhang, Xiao-Bing; Kong, Rong-Mei; Lu, Yi

    2011-07-01

    Metal ion sensors are an important yet challenging field in analytical chemistry. Despite much effort, only a limited number of metal ion sensors are available for practical use because sensor design is often a trial-and-error-dependent process. DNAzyme-based sensors, in contrast, can be developed through a systematic selection that is generalizable for a wide range of metal ions. Here, we summarize recent progress in the design of DNAzyme-based fluorescent, colorimetric, and electrochemical sensors for metal ions, such as Pb2+, Cu2+, Hg2+, and UO22+. In addition, we also describe metal ion sensors based on related DNA molecules, including T-T or C-C mismatches and G-quadruplexes.

  14. Metal Ion Sensors Based on DNAzymes and Related DNA Molecules

    PubMed Central

    Kong, Rong-Mei

    2011-01-01

    Metal ion sensors are an important yet challenging field in analytical chemistry. Despite much effort, only a limited number of metal ion sensors are available for practical use because sensor design is often a trial-and-error-dependent process. DNAzyme-based sensors, in contrast, can be developed through a systematic selection that is generalizable for a wide range of metal ions. Here, we summarize recent progress in the design of DNAzyme-based fluorescent, colorimetric, and electrochemical sensors for metal ions, such as Pb2+, Cu2+, Hg2+, and UO22+ In addition, we also describe metal ion sensors based on related DNA molecules, including T-T or C-C mismatches and G-quadruplexes. PMID:21370984

  15. Neural Network-Based Sensor Validation for Turboshaft Engines

    NASA Technical Reports Server (NTRS)

    Moller, James C.; Litt, Jonathan S.; Guo, Ten-Huei

    1998-01-01

    Sensor failure detection, isolation, and accommodation using a neural network approach is described. An auto-associative neural network is configured to perform dimensionality reduction on the sensor measurement vector and provide estimated sensor values. The sensor validation scheme is applied in a simulation of the T700 turboshaft engine in closed loop operation. Performance is evaluated based on the ability to detect faults correctly and maintain stable and responsive engine operation. The set of sensor outputs used for engine control forms the network input vector. Analytical redundancy is verified by training networks of successively smaller bottleneck layer sizes. Training data generation and strategy are discussed. The engine maintained stable behavior in the presence of sensor hard failures. With proper selection of fault determination thresholds, stability was maintained in the presence of sensor soft failures.

  16. Production of Mixed Alcohols from Bio-syngas over Mo-based Catalyst

    NASA Astrophysics Data System (ADS)

    Qiu, Song-bai; Huang, Wei-wei; Xu, Yong; Liu, Lu; Li, Quan-xin

    2011-02-01

    A series of Mo-based catalysts prepared by sol-gel method using citric acid as complexant were successfully applied in the high efficient production of mixed alcohols from bio-syngas, derived from the biomass gasification. The Cu1Co1Fe1Mo1Zn0.5-6%K catalyst exhibited a higher activity on the space-time yield of mixed alcohols, compared with the other Mo-based catalysts. The carbon conversion significantly increases with rising temperature below 340 °C, but the alcohol selectivity has an opposite trend. The maximum mixed alcohols yield derived from biomass gasification is 494.8 g/(kgcatal·h) with the C2+ (C2—C6 higher alcohols) alcohols of 80.4% under the tested conditions. The alcohol distributions are consistent with the Schulz-Flory plots, except methanol. In the alcohols products, the C2+ alcohols (higher alcohols) dominate with a weight ratio of 70%-85%. The Mo-based catalysts have been characterized by X-ray diffraction and N2 adsorption/desorption. The clean bio-fules of mixed alcohols derived from bio-syngas with higher octane values could be used as transportation fuels or petrol additives.

  17. Cooperative UAV-Based Communications Backbone for Sensor Networks

    SciTech Connect

    Roberts, R S

    2001-10-07

    The objective of this project is to investigate the use of unmanned air vehicles (UAVs) as mobile, adaptive communications backbones for ground-based sensor networks. In this type of network, the UAVs provide communication connectivity to sensors that cannot communicate with each other because of terrain, distance, or other geographical constraints. In these situations, UAVs provide a vertical communication path for the sensors, thereby mitigating geographic obstacles often imposed on networks. With the proper use of UAVs, connectivity to a widely disbursed sensor network in rugged terrain is readily achieved. Our investigation has focused on networks where multiple cooperating UAVs are used to form a network backbone. The advantage of using multiple UAVs to form the network backbone is parallelization of sensor connectivity. Many widely spaced or isolated sensors can be connected to the network at once using this approach. In these networks, the UAVs logically partition the sensor network into sub-networks (subnets), with one UAV assigned per subnet. Partitioning the network into subnets allows the UAVs to service sensors in parallel thereby decreasing the sensor-to-network connectivity. A UAV services sensors in its subnet by flying a route (path) through the subnet, uplinking data collected by the sensors, and forwarding the data to a ground station. An additional advantage of using multiple UAVs in the network is that they provide redundancy in the communications backbone, so that the failure of a single UAV does not necessarily imply the loss of the network.

  18. Tactile MEMS-based sensor for delicate microsurgery

    NASA Astrophysics Data System (ADS)

    Park, Young Soo; Lee, Wooho; Gopalsami, Nachappa; Gundeti, Mohan

    2014-06-01

    This paper presents development of a new MEMS-based tactile microsensor to replicate the delicate sense of touch in robotic surgery. Using an epoxy-based photoresist, SU-8, as substrate, the piezoresistive type sensor is flexible, robust, and easy to fabricate in mass. Sensor characteristic tests indicate adequate sensitivity and linearity, and the multiple sensor elements can match full range of surgical tissue stiffness. Such characteristic nearly match the most delicate sense of touch at the human fingertip. It is expected such a sensor is essential for delicate surgeries, such as handling delicate tissues and microsurgery.

  19. Distributed model-based nonlinear sensor fault diagnosis in wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Lo, Chun; Lynch, Jerome P.; Liu, Mingyan

    2016-01-01

    Wireless sensors operating in harsh environments have the potential to be error-prone. This paper presents a distributive model-based diagnosis algorithm that identifies nonlinear sensor faults. The diagnosis algorithm has advantages over existing fault diagnosis methods such as centralized model-based and distributive model-free methods. An algorithm is presented for detecting common non-linearity faults without using reference sensors. The study introduces a model-based fault diagnosis framework that is implemented within a pair of wireless sensors. The detection of sensor nonlinearities is shown to be equivalent to solving the largest empty rectangle (LER) problem, given a set of features extracted from an analysis of sensor outputs. A low-complexity algorithm that gives an approximate solution to the LER problem is proposed for embedment in resource constrained wireless sensors. By solving the LER problem, sensors corrupted by non-linearity faults can be isolated and identified. Extensive analysis evaluates the performance of the proposed algorithm through simulation.

  20. Severity of alcohol use and problem behaviors among school-based youths in Puerto Rico

    PubMed Central

    Latimer, William W.; Rojas, Vanessa Cecilia; Mancha, Brent Edward

    2009-01-01

    Objectives The present study sought to: (a) categorize youths into groups based on their level of alcohol use and number of symptoms of alcohol abuse and dependence defined in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), and (b) examine whether these categories were associated with other problem behaviors in which youths engage (marijuana use, sexual intercourse, and having been arrested or having trouble with the law). Methods The study is based on a cross-sectional survey administered to 972 school-based youths from one middle school and one high school in San Juan, Puerto Rico. Youths were categorized based on their alcohol use and alcohol problems. These categories were then examined for associations with lifetime marijuana use, lifetime sexual intercourse, and having been arrested or having had trouble with the law in the past year. The original eight categories of alcohol use were collapsed into six categories based on the results. Results For virtually every group characterized by higher severity of alcohol use and alcohol problems, researchers found an increasing prevalence of marijuana use in their lifetimes, increasing odds of sexual intercourse in their lifetimes, and having had trouble with the law in the past year. Conclusions Knowing about variations in alcohol use and alcohol problems may be instrumental in measuring the degree to which youths may also be engaging in a range of other elevated risk behaviors and a progression to more serious forms of alcohol and drug use. PMID:18510792

  1. Efficient implementation of a projection-based wavefront sensor

    NASA Astrophysics Data System (ADS)

    Holder, John; Cain, Stephen C.; Mantica, Peter

    2002-12-01

    In this paper, a new wave front sensor design that utilizes the benefits of image projections is described and analyzed. The projection-based wave front sensor is similar to a Shack-Hartman type wave front sensor, but uses a correlation algorithm as opposed to a centroiding algorithm to estimate optical tilt. This allows the projection-based wave front sensor to estimate optical tilt parameters while guiding off of point sources and extended objects at very low signal to noise ratios. The implementation of the projection-based wave front sensor is described in detail showing important signal processing steps on and off of the focal plane array of the sensor. In this paper the design is tested in simulation for speed and accuracy by processing simulated astronomical data. These simulations demonstrate the accuracy of the projection-based wave front sensor and its superior performance to that of the traditional Shack-Hartman wave front sensor. Timing analysis is presented which shows how the collection and processing of image projections is computationally efficient and lends itself to a wave front sensor design that can produce adaptive optical control signals at speeds of up to 500 hz.

  2. Micro biochemical sensor based on SOI planar optical waveguide

    NASA Astrophysics Data System (ADS)

    Du, Yang; Dong, Ying

    2014-02-01

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

  3. Partner Violence Before and After Couples-Based Alcoholism Treatment for Female Alcoholic Patients

    PubMed Central

    Schumm, Jeremiah A.; O'Farrell, Timothy J.; Murphy, Christopher M.; Fals-Stewart, William

    2010-01-01

    This study examined partner violence before and in the first and second year after behavioral couples therapy (BCT) for 103 married or cohabiting women seeking alcohol dependence treatment and their male partners, and used a demographically matched non-alcoholic comparison sample. The treatment sample received M = 16.7 BCT sessions over 5-6 months. Follow-up rates for the treatment sample at years 1 and 2 were 88% and 83%, respectively. In the year before BCT, 68% of female alcoholic patients had been violent toward their male partner, nearly five times the comparison sample rate of 15%. In the year after BCT, violence prevalence decreased significantly to 31% of the treatment sample. Women were classified as remitted after treatment if they demonstrated abstinence or minimal substance use and no serious consequences related to substance use. In year 1 following BCT, 45% were classified as remitted, and 49% were classified as remitted in year 2. Among remitted patients in the year after BCT, violence prevalence of 22% did not differ from the comparison sample and was significantly lower than the rate among relapsed patients (38%). Results for male-perpetrated violence and for the second year after BCT were similar to the first year. Results supported predictions that partner violence would decrease after BCT, and that clinically significant violence reductions to the level of a non-alcoholic comparison sample would occur for patients whose alcoholism was remitted after BCT. These findings replicate previous research among men with alcoholism. PMID:19968389

  4. Pt/Ceria-based Catalysts for Small Alcohol Electrooxidation

    NASA Astrophysics Data System (ADS)

    Menendez-Mora, Christian L.

    High emissions of fossil-based energy sources have led to scientists around the world to develop new alternatives for the future. In this sense, fuel cells are a remarkable and promising energy option with less environmental impact. The most used fuels for this technology are hydrogen and small chain alcohols, which can be oxidized to transform their chemical energy into electrical power. To do this, fuel cells need catalysts that will act as an active surface where the oxidation can take place. The problem with platinum catalysts is its possible CO poisoning with intermediates that are produced before the complete oxidation of alcohol to CO2. Different approaches have been taken to try to resolve this issue. In this case, cerium oxide (ceria) was selected as a co-catalyst to mitigate the effect of CO poisoning of platinum. Ceria is a compound that has the ability to work as an "oxygen tank" and can donate oxygen to carbon monoxide that is strongly adsorbed at platinum surface to produce CO2 (carbon dioxide), regenerating the Pt surface for further alcohol oxidation. Therefore, enhancing the current density as well as the power output of a fuel cell. First, an occlusion deposition technique was used to prepare platinum/ceria composite electrodes and tested them towards small chain alcohol oxidation such as methanol oxidation reaction in acidic and alkaline media. The preliminary results demonstrated that the Pt/ceria electrodes were more efficient towards methanol electrooxidation when compared to Pt electrodes. This enhancement was attributed to the presence of ceria. A second preparation method was selected for the synthesis of ceria/Pt catalysts. In this case, a hydrothermal method was used and the catalysis were studied for the effect of MeOH, EtOH and n-BuOH oxidation. The observed effect was that electrodes made of Pt/Pt:CeO2-x showed better catalytic effect than Pt/ceria and platinum electrodes. Moreover, a comparison between ceria nanorods versus

  5. sensor for mainstream capnography based on TDLAS

    NASA Astrophysics Data System (ADS)

    Hartmann, A.; Strzoda, R.; Schrobenhauser, R.; Weigel, R.

    2014-09-01

    The setup and signal processing for a mainstream capnography sensor is presented in this paper. The probe exhibits an optical path length of 2.5 cm and is equipped with a vertical-cavity surface-emitting laser at 2 μm. The sensor does not need any calibration, since the CO2 absorption line as well as the laser background is measured using direct tunable diode laser absorption spectroscopy. Unavoidable optical fringes are reduced with a self-developed fringe rejection method. The sensor achieves a concentration resolution <300 ppmv at 4 vol% and a measurement rate >30 Hz.

  6. Liquid density analysis of sucrose and alcoholic beverages using polyimide guided Love-mode acoustic wave sensors

    NASA Astrophysics Data System (ADS)

    Turton, Andrew; Bhattacharyya, Debabrata; Wood, David

    2006-02-01

    A liquid density sensor using Love-mode acoustic waves has been developed which is suitable for use in the food and drinks industries. The sensor has an open flat surface allowing immersion into a sample and simple cleaning. A polyimide waveguide layer allows cheap and simple fabrication combined with a robust chemically resistant surface. The low shear modulus of polyimide allows thin guiding layers giving a high sensitivity. A dual structure with a smooth reference device exhibiting viscous coupling with the wave, and a patterned sense area to trap the liquid causing mass loading, allows discrimination of the liquid density from the square root of the density-viscosity product (ρη)0.5. Frequency shift and insertion loss change were proportional to (ρη)0.5 with a non-linear response due to the non-Newtonian nature of viscous liquids at high frequencies. Measurements were made with sucrose solutions up to 50% and different alcoholic drinks. A maximum sensitivity of 0.13 µg cm-3 Hz-1 was achieved, with a linear frequency response to density. This is the highest liquid density sensitivity obtained for acoustic mode sensors to the best of our knowledge.

  7. Fluorescent sensors based on bacterial fusion proteins

    NASA Astrophysics Data System (ADS)

    Prats Mateu, Batirtze; Kainz, Birgit; Pum, Dietmar; Sleytr, Uwe B.; Toca-Herrera, José L.

    2014-06-01

    Fluorescence proteins are widely used as markers for biomedical and technological purposes. Therefore, the aim of this project was to create a fluorescent sensor, based in the green and cyan fluorescent protein, using bacterial S-layers proteins as scaffold for the fluorescent tag. We report the cloning, expression and purification of three S-layer fluorescent proteins: SgsE-EGFP, SgsE-ECFP and SgsE-13aa-ECFP, this last containing a 13-amino acid rigid linker. The pH dependence of the fluorescence intensity of the S-layer fusion proteins, monitored by fluorescence spectroscopy, showed that the ECFP tag was more stable than EGFP. Furthermore, the fluorescent fusion proteins were reassembled on silica particles modified with cationic and anionic polyelectrolytes. Zeta potential measurements confirmed the particle coatings and indicated their colloidal stability. Flow cytometry and fluorescence microscopy showed that the fluorescence of the fusion proteins was pH dependent and sensitive to the underlying polyelectrolyte coating. This might suggest that the fluorescent tag is not completely exposed to the bulk media as an independent moiety. Finally, it was found out that viscosity enhanced the fluorescence intensity of the three fluorescent S-layer proteins.

  8. A wearable sensor based on CLYC scintillators

    NASA Astrophysics Data System (ADS)

    McDonald, Benjamin S.; Myjak, Mitchell J.; Zalavadia, Mital A.; Smart, John E.; Willett, Jesse A.; Landgren, Peter C.; Greulich, Christopher R.

    2016-06-01

    We have developed a wearable radiation sensor using Cs2LiYCl6:Ce (CLYC) for simultaneous gamma-ray and neutron detection. The system includes two ∅ 2.5 × 2.5cm3 crystals coupled to small, metal-body photomultiplier tubes. A custom, low-power electronics base digitizes the output signal at three time points and enables both pulse height and pulse shape discrimination of gamma rays and neutrons. The total counts, anomaly detection metrics, and identified isotopes are displayed on a small screen. Users may leave the device in unattended mode to collect long-dwell energy spectra. The system stores up to 18 h of one-second data, including energy spectra, and may transfer the data to a remote computer via a wired or wireless connection. The prototype is 18 × 13 × 7.5cm3, weighs 1.3 kg, not including the protective pouch, and runs on six AA alkaline batteries for 29 h with the wireless link active, or 41 h with the wireless link disabled. In this paper, we summarize the system design and present characterization results from the detector modules. The energy resolution is about 6.5% full width at half maximum at 662 keV due to the small photomultiplier tube selected, and the linearity and pulse shape discrimination performance are very good.

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

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

    PubMed

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

    2016-06-12

    The development of structure-switching, electrochemical, aptamer-based sensors over the past ∼10 years has led to a variety of reagentless sensors capable of analytical detection in a range of sample matrices. The crux of this methodology is the coupling of target-induced conformation changes of a redox-labeled aptamer with electrochemical detection of the resulting altered charge transfer rate between the redox molecule and electrode surface. Using aptamer recognition expands the highly sensitive detection ability of electrochemistry to a range of previously inaccessible analytes. In this review, we focus on the methods of sensor fabrication and how sensor signaling is affected by fabrication parameters. We then discuss recent studies addressing the fundamentals of sensor signaling as well as quantitative characterization of the analytical performance of electrochemical aptamer-based sensors. Although the limits of detection of reported electrochemical aptamer-based sensors do not often reach that of gold-standard methods such as enzyme-linked immunosorbent assays, the operational convenience of the sensor platform enables exciting analytical applications that we address. Using illustrative examples, we highlight recent advances in the field that impact important areas of analytical chemistry. Finally, we discuss the challenges and prospects for this class of sensors. PMID:27070185

  11. Selective sensing of alcohols in water influenced by chemically Zeolite coatings on optical fiber sensors

    NASA Astrophysics Data System (ADS)

    Nazari, Marziyeh; Hill, Matthew R.; Duke, Mikel; Sidiroglou, Fotios; Collins, Stephen F.

    2014-05-01

    The application of a MFI type zeolite coating on the end of an optical fiber is presented. Zeolite coatings were directly grown on the freshly cleaved endface of optical fibers. It was found that the produced integrated zeolite-fiber sensors exhibit specific chemical sensitivity towards certain chemicals. The molecular adsorption induced change of zeolite refractive index was studied to understand the sensing mechanisms of the developed sensor system. This work can lead to a new class of portable zeolite thin film enabled miniaturized fiber optic sensors.

  12. Biomimetic virus-based colourimetric sensors

    NASA Astrophysics Data System (ADS)

    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.

  13. Calibration of AVHRR sensors using the reflectance-based method

    NASA Astrophysics Data System (ADS)

    Czapla-Myers, Jeffrey S.; Thome, Kurtis J.; Leisso, Nathan P.

    2007-09-01

    The Remote Sensing Group at the University of Arizona has been active in the vicarious calibration of numerous sensors through the use of ground-based test sites. Recent efforts have included work to develop cross-calibration information between these sensors using the results from the reflectance-based approach. The current work extends the cross-calibration to the AVHRR series of sensors, specifically NOAA-17, and NOAA-18. The results include work done based on data collected by ground-based personnel nearly coincident with the sensor overpasses. The available number of calibrations for the AVHRR series is increased through a set of ground-based radiometers that are deployed without the need for on-site personnel and have been operating for more than three years at Railroad Valley Playa. The spectral, spatial, and temporal characteristics of the 1-km2 large-footprint site at Railroad Valley are well understood. It is therefore well suited for the radiometric calibration of AVHRR, which has a nadir-viewing footprint of 1.1 x 1.1 km. The at-sensor radiance is predicted via a radiative transfer code using atmospheric data from a fully-automated solar radiometer. The results for AVHRR show that errors are currently larger for the automated data sets, but results indicate that the AVHRR sensors studied in this work are consistent with the Aqua and Terra MODIS sensors to within the uncertainties of each sensor.

  14. Amino alcohol-based degradable poly(ester amide) elastomers

    PubMed Central

    Bettinger, Christopher J.; Bruggeman, Joost P.; Borenstein, Jeffrey T.; Langer, Robert S.

    2009-01-01

    Currently available synthetic biodegradable elastomers are primarily composed of crosslinked aliphatic polyesters, which suffer from deficiencies including (1) high crosslink densities, which results in exceedingly high stiffness, (2) rapid degradation upon implantation, or (3) limited chemical moieties for chemical modification. Herein, we have developed poly(1,3-diamino-2-hydroxypropane-co-polyol sebacate)s, a new class of synthetic, biodegradable elastomeric poly(ester amide)s composed of crosslinked networks based on an amino alcohol. These crosslinked networks feature tensile Young’s modulus on the order of 1 MPa and reversable elongations up to 92%. These polymers exhibit in vitro and in vivo biocompatibility. These polymers have projected degradation half-lives up to 20 months in vivo. PMID:18295329

  15. Chip-Based Sensors for Disease Diagnosis

    NASA Astrophysics Data System (ADS)

    Fang, Zhichao

    Nucleic acid analysis is one of the most important disease diagnostic approaches in medical practice, and has been commonly used in cancer biomarker detection, bacterial speciation and many other fields in laboratory. Currently, the application of powerful research methods for genetic analysis, including the polymerase chain reaction (PCR), DNA sequencing, and gene expression profiling using fluorescence microarrays, are not widely used in hospitals and extended-care units due to high-cost, long detection times, and extensive sample preparation. Bioassays, especially chip-based electrochemical sensors, may be suitable for the next generation of rapid, sensitive, and multiplexed detection tools. Herein, we report three different microelectrode platforms with capabilities enabled by nano- and microtechnology: nanoelectrode ensembles (NEEs), nanostructured microelectrodes (NMEs), and hierarchical nanostructured microelectrodes (HNMEs), all of which are able to directly detect unpurified RNA in clinical samples without enzymatic amplification. Biomarkers that are cancer and infectious disease relevant to clinical medicine were chosen to be the targets. Markers were successfully detected with clinically-relevant sensitivity. Using peptide nucleic acids (PNAs) as probes and an electrocatalytic reporter system, NEEs were able to detect prostate cancer-related gene fusions in tumor tissue samples with 100 ng of RNA. The development of NMEs improved the sensitivity of the assay further to 10 aM of DNA target, and multiplexed detection of RNA sequences of different prostate cancer-related gene fusion types was achieved on the chip-based NMEs platform. An HNMEs chip integrated with a bacterial lysis device was able to detect as few as 25 cfu bacteria in 30 minutes and monitor the detection in real time. Bacterial detection could also be performed in neat urine samples. The development of these versatile clinical diagnostic tools could be extended to the detection of various

  16. Recent trends in carbon nanomaterial-based electrochemical sensors for biomolecules: A review.

    PubMed

    Yang, Cheng; Denno, Madelaine E; Pyakurel, Poojan; Venton, B Jill

    2015-08-01

    Carbon nanomaterials are advantageous for electrochemical sensors because they increase the electroactive surface area, enhance electron transfer, and promote adsorption of molecules. Carbon nanotubes (CNTs) have been incorporated into electrochemical sensors for biomolecules and strategies have included the traditional dip coating and drop casting methods, direct growth of CNTs on electrodes and the use of CNT fibers and yarns made exclusively of CNTs. Recent research has also focused on utilizing many new types of carbon nanomaterials beyond CNTs. Forms of graphene are now increasingly popular for sensors including reduced graphene oxide, carbon nanohorns, graphene nanofoams, graphene nanorods, and graphene nanoflowers. In this review, we compare different carbon nanomaterial strategies for creating electrochemical sensors for biomolecules. Analytes covered include neurotransmitters and neurochemicals, such as dopamine, ascorbic acid, and serotonin; hydrogen peroxide; proteins, such as biomarkers; and DNA. The review also addresses enzyme-based electrodes that are used to detect non-electroactive species such as glucose, alcohols, and proteins. Finally, we analyze some of the future directions for the field, pointing out gaps in fundamental understanding of electron transfer to carbon nanomaterials and the need for more practical implementation of sensors. PMID:26320782

  17. Self-cleaning organic vapor sensor based on a nanoporous TiO₂ interferometer.

    PubMed

    Liang, Fengxia; Kelly, Timothy L; Luo, Lin-Bao; Li, Hui; Sailor, Michael J; Li, Yang Yang

    2012-08-01

    Porous thin films of TiO(2) are prepared and their use as chemical sensors for organic vapor analytes is investigated. Thin-film optical interference (Fabry-Perot) fringes in the reflectance spectrum are monitored using Reflectometric Interference Fourier Transform Spectroscopy (RIFTS). Three analytes are employed to probe the sensitivity of the porous TiO(2)-based sensors as a function of analyte vapor pressure: dodecane, isopropyl alcohol (IPA), and pentane. Measured lower limits of detection (3, 30, and 11, 000 ppmv for dodecane, IPA, and pentane, respectively) track the saturation vapor pressures (P(sat)) of the analytes (0.134, 45, and 513 Torr at 25°C for dodecane, IPA, and pentane, respectively); the analyte with the lowest value of P(sat) shows the lowest LLOD. Recovery of the sensor after a saturation dose of analyte is also dependent on P(sat): the sensor displays good recovery from pentane and IPA, and sluggish and incomplete recovery from dodecane. However, irradiation of the porous TiO(2) sensor with UV light in the presence of air accelerates recovery, and this process is attributed to photo-catalyzed oxidation of the analyte at the TiO(2) surface. PMID:22809059

  18. Recent trends in carbon nanomaterial-based electrochemical sensors for biomolecules: A review

    PubMed Central

    Yang, Cheng; Denno, Madelaine E.; Pyakurel, Poojan; Venton, B. Jill

    2015-01-01

    Carbon nanomaterials are advantageous for electrochemical sensors because they increase the electroactive surface area, enhance electron transfer, and promote adsorption of molecules. Carbon nanotubes (CNTs) have been incorporated into electrochemical sensors for biomolecules and strategies have included the traditional dip coating and drop casting methods, direct growth of CNTs on electrodes and the use of CNT fibers and yarns made exclusively of CNTs. Recent research has also focused on utilizing many new types of carbon nanomaterials beyond CNTs. Forms of graphene are now increasingly popular for sensors including reduced graphene oxide, carbon nanohorns, graphene nanofoams, graphene nanorods, and graphene nanoflowers. In this review, we compare different carbon nanomaterial strategies for creating electrochemical sensors for biomolecules. Analytes covered include neurotransmitters and neurochemicals, such as dopamine, ascorbic acid, and serotonin; hydrogen peroxide; proteins, such as biomarkers; and DNA. The review also addresses enzyme-based electrodes that are used to detect non-electroactive species such as glucose, alcohols, and proteins. Finally, we analyze some of the future directions for the field, pointing out gaps in fundamental understanding of electron transfer to carbon nanomaterials and the need for more practical implementation of sensors. PMID:26320782

  19. Polarization-based optical fiber sensor of steel corrosion

    NASA Astrophysics Data System (ADS)

    Hu, Wenbin; Zhu, Cheng; Zheng, Xing; Gao, Min; Guo, Donglai; Chen, Wei

    2015-08-01

    Metal-coated D-shape optical fiber is serving as a polarizer by using its attenuation difference for two orthogonal fundamental modes. This paper presents a novel corrosion sensor, based on an iron-coated optical fiber polarizer. The sensor is fabricated by sputtering a Fe-C film on a side-polished single mode fiber. The extinction ratio and the optical power loss are varying during the corrosion process when the iron-coated sensor is exposed to a corrosive environment. The proposed sensor provides a new approach for monitoring the early-age corrosion of steel structures by tracing the variation of polarization characteristics.

  20. Few-mode fiber based sensor in biomedical application

    NASA Astrophysics Data System (ADS)

    Zhang, Jing

    2015-05-01

    A novel few-mode fiber based sensor for monitoring the vital signs of pulse (heart rate), and breathing rate (respiratory rate) was developed. The sensor was applied in non-invasive measurement of pulse and breathing rates. The pulse, breathing and even body movement affected the sensor's output as the strain on the few-mode fiber changed with these activities. This sensor has simple structure and easy to fabricate. Its signal is easy to monitor. It can be used in the medical equipment in what situation non-invasive realtime monitoring and measurement of pulse rate, and respiratory/body movement pattern of healthy subjects are required.

  1. A carbon nanotube based ammonia sensor on cotton textile

    NASA Astrophysics Data System (ADS)

    Han, Jin-Woo; Kim, Beomseok; Li, Jing; Meyyappan, M.

    2013-05-01

    A single-wall carbon nanotube (CNT) based ammonia (NH3) sensor was implemented on a cotton yarn. Two types of sensors were fabricated: Au/sensing CNT/Au and conducting/sensing/conducting all CNT structures. Two perpendicular Au wires were designed to contact CNT-cotton yarn for metal-CNT sensor, whereas nanotubes were used for the electrode as well as sensing material for the all CNT sensor. The resistance shift of the CNT network upon NH3 was monitored in a chemiresistor approach. The CNT-cotton yarn sensors exhibited uniformity and repeatability. Furthermore, the sensors displayed good mechanical robustness against bending. The present approach can be utilized for low-cost smart textile applications.

  2. Optimization of surface acoustic wave-based rate sensors.

    PubMed

    Xu, Fangqian; Wang, Wen; Shao, Xiuting; Liu, Xinlu; Liang, Yong

    2015-01-01

    The optimization of an surface acoustic wave (SAW)-based rate sensor incorporating metallic dot arrays was performed by using the approach of partial-wave analysis in layered media. The optimal sensor chip designs, including the material choice of piezoelectric crystals and metallic dots, dot thickness, and sensor operation frequency were determined theoretically. The theoretical predictions were confirmed experimentally by using the developed SAW sensor composed of differential delay line-oscillators and a metallic dot array deposited along the acoustic wave propagation path of the SAW delay lines. A significant improvement in sensor sensitivity was achieved in the case of 128° YX LiNbO₃, and a thicker Au dot array, and low operation frequency were used to structure the sensor. PMID:26473865

  3. Optimization of Surface Acoustic Wave-Based Rate Sensors

    PubMed Central

    Xu, Fangqian; Wang, Wen; Shao, Xiuting; Liu, Xinlu; Liang, Yong

    2015-01-01

    The optimization of an surface acoustic wave (SAW)-based rate sensor incorporating metallic dot arrays was performed by using the approach of partial-wave analysis in layered media. The optimal sensor chip designs, including the material choice of piezoelectric crystals and metallic dots, dot thickness, and sensor operation frequency were determined theoretically. The theoretical predictions were confirmed experimentally by using the developed SAW sensor composed of differential delay line-oscillators and a metallic dot array deposited along the acoustic wave propagation path of the SAW delay lines. A significant improvement in sensor sensitivity was achieved in the case of 128° YX LiNbO3, and a thicker Au dot array, and low operation frequency were used to structure the sensor. PMID:26473865

  4. Parallel Microcracks-based Ultrasensitive and Highly Stretchable Strain Sensors.

    PubMed

    Amjadi, Morteza; Turan, Mehmet; Clementson, Cameron P; Sitti, Metin

    2016-03-01

    There is an increasing demand for flexible, skin-attachable, and wearable strain sensors due to their various potential applications. However, achieving strain sensors with both high sensitivity and high stretchability is still a grand challenge. Here, we propose highly sensitive and stretchable strain sensors based on the reversible microcrack formation in composite thin films. Controllable parallel microcracks are generated in graphite thin films coated on elastomer films. Sensors made of graphite thin films with short microcracks possess high gauge factors (maximum value of 522.6) and stretchability (ε ≥ 50%), whereas sensors with long microcracks show ultrahigh sensitivity (maximum value of 11,344) with limited stretchability (ε ≤ 50%). We demonstrate the high performance strain sensing of our sensors in both small and large strain sensing applications such as human physiological activity recognition, human body large motion capturing, vibration detection, pressure sensing, and soft robotics. PMID:26842553

  5. Combine harvester monitor system based on wireless sensor network

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A measurement method based on Wireless Sensor Network (WSN) was developed to monitor the working condition of combine harvester for remote application. Three JN5139 modules were chosen for sensor data acquisition and another two as a router and a coordinator, which could create a tree topology netwo...

  6. Economic and environmental implications of sensor-based N management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Active-light reflectance sensors are currently being studied as a tool to guide inseason “reactive” N application. A recent study evaluated the potential economic benefit and environmental implications for sensor-based N application in corn. Economic benefits and N savings were found for most fields...

  7. An anion sensor based on an organic field effect transistor.

    PubMed

    Minami, Tsuyoshi; Minamiki, Tsukuru; Tokito, Shizuo

    2015-06-11

    We propose an organic field effect transistor (OFET)-based sensor design as a new and innovative platform for anion detection. OFETs could be fabricated on low-cost plastic film substrates using printing technologies, suggesting that OFETs can potentially be applied to practical supramolecular anion sensor devices in the near future. PMID:25966040

  8. A Textile-Based Stretchable Multi-Ion Potentiometric Sensor.

    PubMed

    Parrilla, Marc; Cánovas, Rocío; Jeerapan, Itthipon; Andrade, Francisco J; Wang, Joseph

    2016-05-01

    A textile-based wearable multi-ion potentiometric sensor array is described. The printed flexible sensors operate favorably under extreme mechanical strains (that reflect daily activity) while offering attractive real-time noninvasive monitoring of electrolytes such as sodium and potassium. PMID:26959998

  9. Recent development and application of cataluminescence-based sensors.

    PubMed

    Long, Zi; Ren, Hong; Yang, Yuhan; Ouyang, Jin; Na, Na

    2016-04-01

    A cataluminescence (CTL)-based sensor is fabricated based on the CTL signals generated from catalytic reaction on the surface of solid catalytic materials. CTL-based sensors have been developed since the 1990s and have attracted extensive attention due to long-term stability, linear concentration dependence, good reproducibility and fast response. In recent years, CTL-based sensors and sensor arrays have played important roles in chemical analysis, and were applied to determine the presence of organic gas, inorganic gas, or biological molecules, or to evaluate catalysts. However, due to the relatively low catalytic ability of catalysts or low reactivity of some analytes, high working temperature was normally adopted, which limited the applications. Recently, more advanced techniques were introduced into the fabrication of CTL-based sensors to increase the range of applications, such as advanced enrichment techniques, advanced sampling methods, advanced assisted devices, or multiple detections in array or tandem forms. This review summarizes the recent advancements of CTL-based sensors on development of advanced equipment, advanced sensing materials, new working principles examination, and new applications. Finally, we discuss some critical challenges and prospects in this field. Graphical Abstract The development of cataluminescence-based sensor. PMID:26715246

  10. Gum Sensor: A Stretchable, Wearable, and Foldable Sensor Based on Carbon Nanotube/Chewing Gum Membrane.

    PubMed

    Darabi, Mohammad Ali; Khosrozadeh, Ali; Wang, Quan; Xing, Malcolm

    2015-12-01

    Presented in this work is a novel and facile approach to fabricate an elastic, attachable, and cost-efficient carbon nanotube (CNT)-based strain gauge which can be efficiently used as bodily motion sensors. An innovative and unique method is introduced to align CNTs without external excitations or any complicated procedure. In this design, CNTs are aligned and distributed uniformly on the entire chewing gum by multiple stretching and folding technique. The current sensor is demonstrated to be a linear strain sensor for at least strains up to 200% and can detect strains as high as 530% with a high sensitivity ranging from 12 to 25 and high durability. The gum sensor has been used as bodily motion sensors, and outstanding results are achieved; the sensitivity is quite high, capable of tracing slow breathing. Since the gum sensor can be patterned into various forms, it has wide applications in miniaturized sensors and biochips. Interestingly, we revealed that our gum sensor has the ability to monitor humidity changes with high sensitivity and fast resistance response capable of monitoring human breathing. PMID:26524110

  11. A composite hydrogels-based photonic crystal multi-sensor

    NASA Astrophysics Data System (ADS)

    Chen, Cheng; Zhu, Zhigang; Zhu, Xiangrong; Yu, Wei; Liu, Mingju; Ge, Qiaoqiao; Shih, Wei-Heng

    2015-04-01

    A facile route to prepare stimuli-sensitive poly(vinyl alcohol)/poly(acrylic acid) (PVA/PAA) gelated crystalline colloidal array photonic crystal material was developed. PVA was physically gelated by utilizing an ethanol-assisted method, the resulting hydrogel/crystal composite film was then functionalized with PAA to form an interpenetrating hydrogel film. This sensor film is able to efficiently diffract the visible light and rapidly respond to various environmental stimuli such as solvent, pH and strain, and the accompanying structural color shift can be repeatedly changed and easily distinguished by naked eye.

  12. M13 Bacteriophage Based Protein Sensors

    NASA Astrophysics Data System (ADS)

    Lee, Ju Hun

    Despite significant progress in biotechnology and biosensing, early detection and disease diagnosis remains a critical issue for improving patient survival rates and well-being. Many of the typical detection schemes currently used possess issues such as low sensitivity and accuracy and are also time consuming to run and expensive. In addition, multiplexed detection remains difficult to achieve. Therefore, developing advanced approaches for reliable, simple, quantitative analysis of multiple markers in solution that also are highly sensitive are still in demand. In recent years, much of the research has primarily focused on improving two key components of biosensors: the bio-recognition agent (bio-receptor) and the transducer. Particular bio-receptors that have been used include antibodies, aptamers, molecular imprinted polymers, and small affinity peptides. In terms of transducing agents, nanomaterials have been considered as attractive candidates due to their inherent nanoscale size, durability and unique chemical and physical properties. The key focus of this thesis is the design of a protein detection and identification system that is based on chemically engineered M13 bacteriophage coupled with nanomaterials. The first chapter provides an introduction of biosensors and M13 bacteriophage in general, where the advantages of each are provided. In chapter 2, an efficient and enzyme-free sensor is demonstrated from modified M13 bacteriophage to generate highly sensitive colorimetric signals from gold nanocrystals. In chapter 3, DNA conjugated M13 were used to enable facile and rapid detection of antigens in solution that also provides modalities for identification. Lastly, high DNA loadings per phage was achieved via hydrozone chemistry and these were applied in conjunction with Raman active DNA-gold/silver core/shell nanoparticles toward highly sensitive SERS sensing.

  13. A Risk-Based Sensor Placement Methodology

    SciTech Connect

    Lee, Ronald W; Kulesz, James J

    2006-08-01

    A sensor placement methodology is proposed to solve the problem of optimal location of sensors or detectors to protect population against the exposure to and effects of known and/or postulated chemical, biological, and/or radiological threats. Historical meteorological data are used to characterize weather conditions as wind speed and direction pairs with the percentage of occurrence of the pairs over the historical period. The meteorological data drive atmospheric transport and dispersion modeling of the threats, the results of which are used to calculate population at risk against standard exposure levels. Sensor locations are determined via a dynamic programming algorithm where threats captured or detected by sensors placed in prior stages are removed from consideration in subsequent stages. Moreover, the proposed methodology provides a quantification of the marginal utility of each additional sensor or detector. Thus, the criterion for halting the iterative process can be the number of detectors available, a threshold marginal utility value, or the cumulative detection of a minimum factor of the total risk value represented by all threats.

  14. Multipoint sensor based on fiber Bragg gratings

    NASA Astrophysics Data System (ADS)

    Méndez-Zepeda, O.; Muñoz-Aguirre, S.; Beltrán-Pérez, G.; Castillo-Mixcóatl, J.

    2011-01-01

    In some control and industrial measurement systems of physical variables (pressure, temperature, flow, etc) it is necessary one system and one sensor to control each process. On the other hand, there are systems such as PLC (Programmable Logic Control), which can process several signals simultaneously. However it is still necessary to use one sensor for each variable. Therefore, in the present work the use of a multipoint sensor to solve such problem has been proposed. The sensor consists of an optical fiber laser with two Fabry-Perot cavities constructed using fiber Bragg gratings (FBG). In the same system is possible to measure changes in two variables by detecting the intermodal separation frequency of each cavity and evaluate their amplitudes. The intermodal separation frequency depends on each cavity length. The sensor signals are monitored through an oscilloscope or a PCI card and after that acquired by PC, where they are analyzed and displayed. Results of the evaluation of the intermodal frequency separation peak amplitude behavior with FBG stretching are presented.

  15. Ethanol sensor based on nanocrystallite cadmium ferrite

    SciTech Connect

    Gadkari, Ashok B.; Shinde, Tukaram J.; Vasambekar, Pramod N.

    2015-06-24

    The cadmium ferrite was synthesized by oxalate co-precipitation method. The crystal structure and surface morphology were examined by X-ray diffraction and SEM techniques, respectively. The nanocrystallite CdFe{sub 2}O{sub 4} sensor was tested for LPG, Cl{sub 2} and C{sub 2}H{sub 5}OH. The sensitivity was measured at various operating temperatures in the range of 100-400°C. The sensor shows highest sensitivity and selectivity to C{sub 2}H{sub 5}OH at 350°C. The response and recovery time was measured at operating temperature of 350°C. The sensor exhibits a lower response and recovery time for LPG and Cl{sub 2} as compared to ethanol.

  16. Nanoarchitectonics for carbon-material-based sensors.

    PubMed

    Ariga, Katsuhiko; Minami, Kosuke; Shrestha, Lok Kumar

    2016-04-25

    Recently, the nanoarchitectonics concept has been proposed to fabricate functional materials on the basis of concerted harmonization actions to control materials organization. In this review, we introduce recent several sensor designs from viewpoints of nanoarchitectonics that are classified into three categories: (i) inside nanoarchitectonics, (ii) outside nanoarchitectonics, and (iii) hierarchic nanoarchitectonics. In addition, various nanocarbons, such as carbon nanotubes, graphene derivatives, fullerene assemblies and nanoporous carbons, are selected as standard materials. In the first section, design and fabrication of mesoporous or nanoporous materials for enhanced sensing are especially exemplified as inside nanoarchitectonics. In the next section, recent examples of layer-by-layer nanoarchitectures for sensor fabrications are explained for outside nanoarchitectonics. Finally, their combined strategies for hierarchic carbon nanoarchitectonics are introduced as advanced sensor materials designs. PMID:26876528

  17. Electrostatic Limit of Detection of Nanowire-Based Sensors.

    PubMed

    Henning, Alex; Molotskii, Michel; Swaminathan, Nandhini; Vaknin, Yonathan; Godkin, Andrey; Shalev, Gil; Rosenwaks, Yossi

    2015-10-01

    Scanning gate microscopy is used to determine the electrostatic limit of detection (LOD) of a nanowire (NW) based chemical sensor with a precision of sub-elementary charge. The presented method is validated with an electrostatically formed NW whose active area and shape are tunable by biasing a multiple gate field-effect transistor (FET). By using the tip of an atomic force microscope (AFM) as a local top gate, the field effect of adsorbed molecules is emulated. The tip induced charge is quantified with an analytical electrostatic model and it is shown that the NW sensor is sensitive to about an elementary charge and that the measurements with the AFM tip are in agreement with sensing of ethanol vapor. This method is applicable to any FET-based chemical and biological sensor, provides a means to predict the absolute sensor performance limit, and suggests a standardized way to compare LODs and sensitivities of various sensors. PMID:26173993

  18. Standards-Based Wireless Sensor Networking Protocols for Spaceflight Applications

    NASA Technical Reports Server (NTRS)

    Wagner, Raymond S.

    2010-01-01

    Wireless sensor networks (WSNs) have the capacity to revolutionize data gathering in both spaceflight and terrestrial applications. WSNs provide a huge advantage over traditional, wired instrumentation since they do not require wiring trunks to connect sensors to a central hub. This allows for easy sensor installation in hard to reach locations, easy expansion of the number of sensors or sensing modalities, and reduction in both system cost and weight. While this technology offers unprecedented flexibility and adaptability, implementing it in practice is not without its difficulties. Recent advances in standards-based WSN protocols for industrial control applications have come a long way to solving many of the challenges facing practical WSN deployments. In this paper, we will overview two of the more promising candidates - WirelessHART from the HART Communication Foundation and ISA100.11a from the International Society of Automation - and present the architecture for a new standards-based sensor node for networking and applications research.

  19. Study of radiation characteristic of airborne sensor based on tarps

    NASA Astrophysics Data System (ADS)

    Yu, Xiujuan; Qi, Weijun; Fang, Aiping

    2014-07-01

    The radiation characteristic of aerial sensor directly affects the quantitative application level of sensor data. In order to study the radiation characteristic, we carried out the radiation characteristic test based on ground tarps laid onto the calibration field of image quality in Anyang, Henan. The airborne sensor was calibrated adopting reflectance-based method. 8 gray-scale tarps and 4 tarps of high reflectance were laid onto the calibration field and they were all with better Lambert radiation characteristic and spectral performance uniformity. Preliminary results show that the bias is larger and the effective dynamic range is smaller and the SNR is lower but the linearity and repeatability are better which can be used to test the response performance of the sensor. Overall, the radiation characteristic tarps laid on the calibration field are suitable for the study of in-flight radiation characteristic of the aerial digital sensor.

  20. Calibration of a HTS Based LOX 400 mm Level Sensor

    NASA Astrophysics Data System (ADS)

    Karunanithi, R.; Jacob, S.; Nadig, D. S.; Prasad, M. V. N.; Gour, Abhay S.; Pankaj, S.; Gowthaman, M.; Sudharshan, H.

    The measurement of the cryogen level in a cryostage of space crafts is crucial. At the same time the weight of the sensor should be small as it affects the payload fraction of the space craft. An attempt to develop a HTS based level sensor of 400 mm for Liquid Oxygen (LOX) measurement was made. In the initial phase of testing, loss of superconductivity of HTS wire in LOX inside a cryostat was noticed. Thus, a new four wall cryostat was designed to have a stable LOX level to provide thermal stability to the HTS based LOX sensor. The calibration of the developed sensor was carried out against capacitance level sensor which was pre calibrated using diode array to verify its linearity and performance for different current excitation levels. The calibrations were carried out without heater wires. The automatic data logging was accomplished using a program developed in LabVIEW 11.0.

  1. Partner Violence before and after Couples-Based Alcoholism Treatment for Female Alcoholic Patients

    ERIC Educational Resources Information Center

    Schumm, Jeremiah A.; O'Farrell, Timothy J.; Murphy, Christopher M.; Fals-Stewart, William

    2009-01-01

    This study examined partner violence before and in the 1st and 2nd year after behavioral couples therapy (BCT) for 103 married or cohabiting women seeking alcohol dependence treatment and their male partners; it used a demographically matched nonalcoholic comparison sample. The treatment sample received M = 16.7 BCT sessions over 5-6 months.…

  2. Textile-Based Weft Knitted Strain Sensors: Effect of Fabric Parameters on Sensor Properties

    PubMed Central

    Atalay, Ozgur; Kennon, William Richard; Husain, Muhammad Dawood

    2013-01-01

    The design and development of textile-based strain sensors has been a focus of research and many investigators have studied this subject. This paper presents a new textile-based strain sensor design and shows the effect of base fabric parameters on its sensing properties. Sensing fabric could be used to measure articulations of the human body in the real environment. The strain sensing fabric was produced by using electronic flat-bed knitting technology; the base fabric was produced with elastomeric yarns in an interlock arrangement and a conductive yarn was embedded in this substrate to create a series of single loop structures. Experimental results show that there is a strong relationship between base fabric parameters and sensor properties. PMID:23966199

  3. Sensor Fusion Based Model for Collision Free Mobile Robot Navigation.

    PubMed

    Almasri, Marwah; Elleithy, Khaled; Alajlan, Abrar

    2015-01-01

    Autonomous mobile robots have become a very popular and interesting topic in the last decade. Each of them are equipped with various types of sensors such as GPS, camera, infrared and ultrasonic sensors. These sensors are used to observe the surrounding environment. However, these sensors sometimes fail and have inaccurate readings. Therefore, the integration of sensor fusion will help to solve this dilemma and enhance the overall performance. This paper presents a collision free mobile robot navigation based on the fuzzy logic fusion model. Eight distance sensors and a range finder camera are used for the collision avoidance approach where three ground sensors are used for the line or path following approach. The fuzzy system is composed of nine inputs which are the eight distance sensors and the camera, two outputs which are the left and right velocities of the mobile robot's wheels, and 24 fuzzy rules for the robot's movement. Webots Pro simulator is used for modeling the environment and the robot. The proposed methodology, which includes the collision avoidance based on fuzzy logic fusion model and line following robot, has been implemented and tested through simulation and real time experiments. Various scenarios have been presented with static and dynamic obstacles using one robot and two robots while avoiding obstacles in different shapes and sizes. PMID:26712766

  4. Elaboration, activity and stability of silica-based nitroaromatic sensors.

    PubMed

    Mercier, Dimitri; Pereira, Franck; Méthivier, Christophe; Montméat, Pierre; Hairault, Lionel; Pradier, Claire-Marie

    2013-08-21

    Functionalized silica-based thin films, modified with hydrophobic groups, were synthesized and used as sensors for nitroaromatic compound (NAC) specific detection. Their performance and behavior, in terms of stability, ageing and regeneration, have been fully characterized by combining chemical characterization techniques and electron microscopy. NAC was efficiently and specifically detected using these silica-based sensors, but showed a great degradation in the presence of humidity. Moreover, the sensor sensitivity seriously decreases with storage time. Methyl- and phenyl-functionalization helped to overcome this humidity sensitivity. Surface characterization enabled us to establish a direct correlation between the appearance, and increasing amount, of adsorbed carbonyl-containing species, and sensor efficiency. This contamination, appearing after only one month, was particularly important when sensors were stored in plastic containers. Rinsing with cyclohexane enables us to recover part of the sensor performance but does not yield a complete regeneration of the sensors. This work led us to the definition of optimized elaboration and storage conditions for nitroaromatic sensors. PMID:23812282

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

    PubMed Central

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

    2014-01-01

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

  6. Sensor Fusion Based Model for Collision Free Mobile Robot Navigation

    PubMed Central

    Almasri, Marwah; Elleithy, Khaled; Alajlan, Abrar

    2015-01-01

    Autonomous mobile robots have become a very popular and interesting topic in the last decade. Each of them are equipped with various types of sensors such as GPS, camera, infrared and ultrasonic sensors. These sensors are used to observe the surrounding environment. However, these sensors sometimes fail and have inaccurate readings. Therefore, the integration of sensor fusion will help to solve this dilemma and enhance the overall performance. This paper presents a collision free mobile robot navigation based on the fuzzy logic fusion model. Eight distance sensors and a range finder camera are used for the collision avoidance approach where three ground sensors are used for the line or path following approach. The fuzzy system is composed of nine inputs which are the eight distance sensors and the camera, two outputs which are the left and right velocities of the mobile robot’s wheels, and 24 fuzzy rules for the robot’s movement. Webots Pro simulator is used for modeling the environment and the robot. The proposed methodology, which includes the collision avoidance based on fuzzy logic fusion model and line following robot, has been implemented and tested through simulation and real time experiments. Various scenarios have been presented with static and dynamic obstacles using one robot and two robots while avoiding obstacles in different shapes and sizes. PMID:26712766

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

    PubMed

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

    2014-01-01

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

  8. MIS-based sensors with hydrogen selectivity

    DOEpatents

    Li; ,Dongmei; Medlin, J. William; McDaniel, Anthony H.; Bastasz, Robert J.

    2008-03-11

    The invention provides hydrogen selective metal-insulator-semiconductor sensors which include a layer of hydrogen selective material. The hydrogen selective material can be polyimide layer having a thickness between 200 and 800 nm. Suitable polyimide materials include reaction products of benzophenone tetracarboxylic dianhydride 4,4-oxydianiline m-phenylene diamine and other structurally similar materials.

  9. Performance Analysis of a Convection-Based Tilt Sensor

    NASA Astrophysics Data System (ADS)

    Ju Chan Choi,; Seong Ho Kong,

    2010-06-01

    This paper presents fabrication sequence and performance improving methods for convection-based tilt sensor. Also a packaging method to minimize the effect of environmental temperature fluctuation is proposed. Both electrolytic solution-based and air convection-based tilt sensors realized using micro-electro-mechanical-system (MEMS) technology have been previously reported by our research group. Although the MEMS-based electrolytic tilt sensor shows merited characteristics, such as wider operating tilt range, lower cost and compactness, compared to commercialized conventional electrolytic tilt sensors, it still suffers from metal electrode corrosion, electrolyte deterioration, surface tension of the electrolyte, and difficulty in packaging. In order to avoid those demerits, convective tilt sensor using air medium instead of electrolytic solution has been proposed and its fundamental performances has also been demonstrated in the previous works. In this paper, the effect of air medium condition on sensitivity of proposed convective tilt sensor has been investigated. In addition, a packaging method utilizing the Peltier device is presented to minimize environmental thermal effect without additional temperature compensation circuit. It is expected that this technique can be similarly applied to improve the performance and reliability of other sensors using gas media.

  10. Standards-based sensor interoperability and networking SensorWeb: an overview

    NASA Astrophysics Data System (ADS)

    Bolling, Sam

    2012-06-01

    The War fighter lacks a unified Intelligence, Surveillance, and Reconnaissance (ISR) environment to conduct mission planning, command and control (C2), tasking, collection, exploitation, processing, and data discovery of disparate sensor data across the ISR Enterprise. Legacy sensors and applications are not standardized or integrated for assured, universal access. Existing tasking and collection capabilities are not unified across the enterprise, inhibiting robust C2 of ISR including near-real time, cross-cueing operations. To address these critical needs, the National Measurement and Signature Intelligence (MASINT) Office (NMO), and partnering Combatant Commands and Intelligence Agencies are developing SensorWeb, an architecture that harmonizes heterogeneous sensor data to a common standard for users to discover, access, observe, subscribe to and task sensors. The SensorWeb initiative long term goal is to establish an open commercial standards-based, service-oriented framework to facilitate plug and play sensors. The current development effort will produce non-proprietary deliverables, intended as a Government off the Shelf (GOTS) solution to address the U.S. and Coalition nations' inability to quickly and reliably detect, identify, map, track, and fully understand security threats and operational activities.

  11. Portable Nanoparticle-Based Sensors for Food Safety Assessment

    PubMed Central

    Bülbül, Gonca; Hayat, Akhtar; Andreescu, Silvana

    2015-01-01

    The use of nanotechnology-derived products in the development of sensors and analytical measurement methodologies has increased significantly over the past decade. Nano-based sensing approaches include the use of nanoparticles (NPs) and nanostructures to enhance sensitivity and selectivity, design new detection schemes, improve sample preparation and increase portability. This review summarizes recent advancements in the design and development of NP-based sensors for assessing food safety. The most common types of NPs used to fabricate sensors for detection of food contaminants are discussed. Selected examples of NP-based detection schemes with colorimetric and electrochemical detection are provided with focus on sensors for the detection of chemical and biological contaminants including pesticides, heavy metals, bacterial pathogens and natural toxins. Current trends in the development of low-cost portable NP-based technology for rapid assessment of food safety as well as challenges for practical implementation and future research directions are discussed. PMID:26690169

  12. Chemical sensors based on the modification of a resonator cavity

    NASA Astrophysics Data System (ADS)

    Hennig, Oliver; Mendes, Sergio B.; Fallahi, Mahmoud; Peyghambarian, Nasser

    1999-02-01

    In this paper, we present a chemical sensor based on the modification of an optical resonator: the optical path length of the resonant cavity is changed by the chemical in question, thus shifting its resonant frequency.

  13. Semiconducting Metal Oxide Based Sensors for Selective Gas Pollutant Detection

    PubMed Central

    Kanan, Sofian M.; El-Kadri, Oussama M.; Abu-Yousef, Imad A.; Kanan, Marsha C.

    2009-01-01

    A review of some papers published in the last fifty years that focus on the semiconducting metal oxide (SMO) based sensors for the selective and sensitive detection of various environmental pollutants is presented. PMID:22408500

  14. Portable Nanoparticle-Based Sensors for Food Safety Assessment.

    PubMed

    Bülbül, Gonca; Hayat, Akhtar; Andreescu, Silvana

    2015-01-01

    The use of nanotechnology-derived products in the development of sensors and analytical measurement methodologies has increased significantly over the past decade. Nano-based sensing approaches include the use of nanoparticles (NPs) and nanostructures to enhance sensitivity and selectivity, design new detection schemes, improve sample preparation and increase portability. This review summarizes recent advancements in the design and development of NP-based sensors for assessing food safety. The most common types of NPs used to fabricate sensors for detection of food contaminants are discussed. Selected examples of NP-based detection schemes with colorimetric and electrochemical detection are provided with focus on sensors for the detection of chemical and biological contaminants including pesticides, heavy metals, bacterial pathogens and natural toxins. Current trends in the development of low-cost portable NP-based technology for rapid assessment of food safety as well as challenges for practical implementation and future research directions are discussed. PMID:26690169

  15. Planar Laser-Based QEPAS Trace Gas Sensor

    PubMed Central

    Ma, Yufei; He, Ying; Chen, Cheng; Yu, Xin; Zhang, Jingbo; Peng, Jiangbo; Sun, Rui; Tittel, Frank K.

    2016-01-01

    A novel quartz enhanced photoacoustic spectroscopy (QEPAS) trace gas detection scheme is reported in this paper. A cylindrical lens was employed for near-infrared laser focusing. The laser beam was shaped as a planar line laser between the gap of the quartz tuning fork (QTF) prongs. Compared with a spherical lens-based QEPAS sensor, the cylindrical lens-based QEPAS sensor has the advantages of easier laser beam alignment and a reduction of stringent stability requirements. Therefore, the reported approach is useful in long-term and continuous sensor operation. PMID:27367686

  16. Planar Laser-Based QEPAS Trace Gas Sensor.

    PubMed

    Ma, Yufei; He, Ying; Chen, Cheng; Yu, Xin; Zhang, Jingbo; Peng, Jiangbo; Sun, Rui; Tittel, Frank K

    2016-01-01

    A novel quartz enhanced photoacoustic spectroscopy (QEPAS) trace gas detection scheme is reported in this paper. A cylindrical lens was employed for near-infrared laser focusing. The laser beam was shaped as a planar line laser between the gap of the quartz tuning fork (QTF) prongs. Compared with a spherical lens-based QEPAS sensor, the cylindrical lens-based QEPAS sensor has the advantages of easier laser beam alignment and a reduction of stringent stability requirements. Therefore, the reported approach is useful in long-term and continuous sensor operation. PMID:27367686

  17. Plasmonics Based Harsh Environment Compatible Chemical Sensors

    SciTech Connect

    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

  18. Tensile stress distribution sensors based on amorphous alloys

    NASA Astrophysics Data System (ADS)

    Hristoforou, E.; Reilly, R. E.

    1993-02-01

    In this paper, we report experimental results on the response of tensile stress sensors based on the magnetostrictive delay line technique, operating under pulsed field excitation. Their operation is based on the change of the magnetic circuit due to the change of the relative permeability of an amorphous ribbon when tensile stress is applied on it. They are low compliance sensors and can be used in cases where large displacement of the active core is not desirable.

  19. Elastomeric Polymer Resonant Waveguide Grating based Pressure Sensor

    PubMed Central

    Song, Fuchuan; Xie, Antonio Jou; Seo, Sang-Woo

    2014-01-01

    In this paper, we demonstrate an elastomeric polymer resonant waveguide grating structure to be used as a pressure sensor. The applied pressure is measured by optical resonance spectrum peak shift. The sensitivity - as high as 86.74pm/psi or 12.58pm/kPa - has been experimentally obtained from a fabricated sensor. Potentially, the sensitivity of the demonstrated sensor can be tuned to different pressure ranges by the choices of elastic properties and layer thicknesses of the waveguide and cladding layers. The simulation results agree well with experimental results and indicate that the dominant effect on the sensor is the change of grating period when external pressure is applied. Based on the two-dimensional planar structure, the demonstrated sensor can be used to measure applied surface pressure optically, which has potential applications for optical ultrasound imaging and pressure wave detection/mapping. PMID:25419447

  20. Glucose sensors based on electrospun nanofibers: a review.

    PubMed

    Senthamizhan, Anitha; Balusamy, Brabu; Uyar, Tamer

    2016-02-01

    The worldwide increase in the number of people suffering from diabetes has been the driving force for the development of glucose sensors. The recent past has devised various approaches to formulate glucose sensors using various nanostructure materials. This review presents a combined survey of these various approaches, with emphasis on the current progress in the use of electrospun nanofibers and their composites. Outstanding characteristics of electrospun nanofibers, including high surface area, porosity, flexibility, cost effectiveness, and portable nature, make them a good choice for sensor applications. Particularly, their nature of possessing a high surface area makes them the right fit for large immobilization sites, resulting in increased interaction with analytes. Thus, these electrospun nanofiber-based glucose sensors present a number of advantages, including increased life time, which is greatly needed for practical applications. Taking all these facts into consideration, we have highlighted the latest significant developments in the field of glucose sensors across diverse approaches. PMID:26573168

  1. Sensor network based vehicle classification and license plate identification system

    SciTech Connect

    Frigo, Janette Rose; Brennan, Sean M; Rosten, Edward J; Raby, Eric Y; Kulathumani, Vinod K

    2009-01-01

    Typically, for energy efficiency and scalability purposes, sensor networks have been used in the context of environmental and traffic monitoring applications in which operations at the sensor level are not computationally intensive. But increasingly, sensor network applications require data and compute intensive sensors such video cameras and microphones. In this paper, we describe the design and implementation of two such systems: a vehicle classifier based on acoustic signals and a license plate identification system using a camera. The systems are implemented in an energy-efficient manner to the extent possible using commercially available hardware, the Mica motes and the Stargate platform. Our experience in designing these systems leads us to consider an alternate more flexible, modular, low-power mote architecture that uses a combination of FPGAs, specialized embedded processing units and sensor data acquisition systems.

  2. Metamaterial-based sensor for skin disease diagnostics

    NASA Astrophysics Data System (ADS)

    La Spada, L.; Iovine, R.; Tarparelli, R.; Vegni, L.

    2013-05-01

    Skin absorption properties, under diseases conditions, are modified due to the structural variations of chromophores and pigments. The measurement of such different absorptions can be a useful tool for the recognition of different skin diseases. In this study the design of a multi-resonant metamaterial-based sensor operating in the optical frequency range is presented. The sensor has been designed, in order to have multiple specific resonant frequencies, tuned to the skin components spectral characteristics. A change in the frequency amplitude of the sensor response is related to the different absorption rate of skin chromophores and pigments. A new analytical model, describing the multi-resonant sensor behaviour, is developed. Good agreement among analytical and numerical results was achieved. Full-wave simulations have validated the capability of the proposed sensor to identify different skin diseases.

  3. Novel localized surface plasmon resonance based optical fiber sensor

    NASA Astrophysics Data System (ADS)

    Muri, Harald Ian D. I.; Hjelme, Dag R.

    2016-03-01

    Over the last decade various optical fiber sensing schemes have been proposed based on local surface plasmon resonance (LSPR). LSPR are interacting with the evanescent field from light propagating in the fiber core or by interacting with the light at the fiber end face. Sensor designs utilizing the fiber end face is strongly preferred from a manufacturing point of view. However, the different techniques available to immobilize metallic nanostructures on the fiber end face for LSPR sensing is limited to essentially a monolayer, either by photolithographic structuring of metal film, thermal nucleation of metal film, or by random immobilization of nanoparticles (NP). In this paper, we report on a novel LSPR based optical fiber sensor architecture. The sensor is prepared by immobilizing gold NP's in a hydrogel droplet polymerized on the fiber end face. This design has several advantages over earlier designs. It dramatically increase the number of NP's available for sensing, it offers precise control over the NP density, and the NPs are position in a true 3D aqueous environment. The sensor design is also compatible with low cost manufacturing. The sensor design can measure volumetric changes in a stimuli-responsive hydrogel or measure binding to receptors on the NP surface. It can also be used as a two-parameter sensor by utilizing both effects. We present results from proof-of-concept experiments demonstrating a pH sensor based on LSPR sensing in a poly(acrylamide-co-acrylic acid) hydrogel embedding gold nanoparticles.

  4. Haem-based sensors: a still growing old superfamily.

    PubMed

    Germani, Francesca; Moens, Luc; Dewilde, Sylvia

    2013-01-01

    The haem-based sensors are chimeric multi-domain proteins responsible for the cellular adaptive responses to environmental changes. The signal transduction is mediated by the sensing capability of the haem-binding domain, which transmits a usable signal to the cognate transmitter domain, responsible for providing the adequate answer. Four major families of haem-based sensors can be recognized, depending on the nature of the haem-binding domain: (i) the haem-binding PAS domain, (ii) the CO-sensitive carbon monoxide oxidation activator, (iii) the haem NO-binding domain, and (iv) the globin-coupled sensors. The functional classification of the haem-binding sensors is based on the activity of the transmitter domain and, traditionally, comprises: (i) sensors with aerotactic function; (ii) sensors with gene-regulating function; and (iii) sensors with unknown function. We have implemented this classification with newly identified proteins, that is, the Streptomyces avermitilis and Frankia sp. that present a C-terminal-truncated globin fused to an N-terminal cofactor-free monooxygenase, the structural-related class of non-haem globins in Bacillus subtilis, Moorella thermoacetica, and Bacillus anthracis, and a haemerythrin-coupled diguanylate cyclase in Vibrio cholerae. This review summarizes the structures, the functions, and the structure-function relationships known to date on this broad protein family. We also propose unresolved questions and new possible research approaches. PMID:24054793

  5. Electrochemical Sensors and Biosensors Based on Nanomaterials and Nanostructures

    SciTech Connect

    Zhu, Chengzhou; Yang, Guohai; Li, He; Du, Dan; Lin, Yuehe

    2014-10-29

    We report that considerable attention has been devoted to the integration of recognition elements with electronic elements to develop electrochemical sensors and biosensors.Various electrochemical devices, such as amperometric sensors, electrochemical impedance sensors, and electrochemical luminescence sensors as well as photoelectrochemical sensors, provide wide applications in the detection of chemical and biological targets in terms of electrochemical change of electrode interfaces. Here, this review focuses on recent advances in electrochemical sensors and biosensors based on nanomaterials and nanostructures during 2013 to 2014. The aim of this effort is to provide the reader with a clear and concise view of new advances in areas ranging from electrode engineering, strategies for electrochemical signal amplification, and novel electroanalytical techniques used in the miniaturization and integration of the sensors. Moreover, the authors have attempted to highlight areas of the latest and significant development of enhanced electrochemical nanosensors and nanobiosensors that inspire broader interests across various disciplines. Electrochemical sensors for small molecules, enzyme-based biosensors, genosensors, immunosensors, and cytosensors are reviewed herein (Figure 1). Such novel advances are important for the development of electrochemical sensors that open up new avenues and methods for future research. In conclusion, we recommend readers interested in the general principles of electrochemical sensors and electrochemical methods to refer to other excellent literature for a broad scope in this area.(3, 4) However, due to the explosion of publications in this active field, we do not claim that this Review includes all of the published works in the past two years and we apologize to the authors of excellent work, which is unintentionally left out.

  6. Optical hydrogen sensors based on metal-hydrides

    NASA Astrophysics Data System (ADS)

    Slaman, M.; Westerwaal, R.; Schreuders, H.; Dam, B.

    2012-06-01

    For many hydrogen related applications it is preferred to use optical hydrogen sensors above electrical systems. Optical sensors reduce the risk of ignition by spark formation and are less sensitive to electrical interference. Currently palladium and palladium alloys are used for most hydrogen sensors since they are well known for their hydrogen dissociation and absorption properties at relatively low temperatures. The disadvantages of palladium in sensors are the low optical response upon hydrogen loading, the cross sensitivity for oxygen and carbon, the limited detection range and the formation of micro-cracks after some hydrogen absorption/desorption cycles. In contrast to Pd, we find that the use of magnesium or rear earth bases metal-hydrides in optical hydrogen sensors allow tuning of the detection levels over a broad pressure range, while maintaining a high optical response. We demonstrate a stable detection layer for detecting hydrogen below 10% of the lower explosion limit in an oxygen rich environment. This detection layer is deposited at the bare end of a glass fiber as a micro-mirror and is covered with a thin layer of palladium. The palladium layer promotes the hydrogen uptake at room temperature and acts as a hydrogen selective membrane. To protect the sensor for a long time in air a final layer of a hydrophobic fluorine based coating is applied. Such a sensor can be used for example as safety detector in automotive applications. We find that this type of fiber optic hydrogen sensor is also suitable for hydrogen detection in liquids. As example we demonstrate a sensor for detecting a broad range of concentrations in transformer oil. Such a sensor can signal a warning when sparks inside a high voltage power transformer decompose the transformer oil over a long period.

  7. Electrochemical Sensors and Biosensors Based on Nanomaterials and Nanostructures

    DOE PAGESBeta

    Zhu, Chengzhou; Yang, Guohai; Li, He; Du, Dan; Lin, Yuehe

    2014-10-29

    We report that considerable attention has been devoted to the integration of recognition elements with electronic elements to develop electrochemical sensors and biosensors.Various electrochemical devices, such as amperometric sensors, electrochemical impedance sensors, and electrochemical luminescence sensors as well as photoelectrochemical sensors, provide wide applications in the detection of chemical and biological targets in terms of electrochemical change of electrode interfaces. Here, this review focuses on recent advances in electrochemical sensors and biosensors based on nanomaterials and nanostructures during 2013 to 2014. The aim of this effort is to provide the reader with a clear and concise view of new advancesmore » in areas ranging from electrode engineering, strategies for electrochemical signal amplification, and novel electroanalytical techniques used in the miniaturization and integration of the sensors. Moreover, the authors have attempted to highlight areas of the latest and significant development of enhanced electrochemical nanosensors and nanobiosensors that inspire broader interests across various disciplines. Electrochemical sensors for small molecules, enzyme-based biosensors, genosensors, immunosensors, and cytosensors are reviewed herein (Figure 1). Such novel advances are important for the development of electrochemical sensors that open up new avenues and methods for future research. In conclusion, we recommend readers interested in the general principles of electrochemical sensors and electrochemical methods to refer to other excellent literature for a broad scope in this area.(3, 4) However, due to the explosion of publications in this active field, we do not claim that this Review includes all of the published works in the past two years and we apologize to the authors of excellent work, which is unintentionally left out.« less

  8. Modeling Sensor Reliability in Fault Diagnosis Based on Evidence Theory

    PubMed Central

    Yuan, Kaijuan; Xiao, Fuyuan; Fei, Liguo; Kang, Bingyi; Deng, Yong

    2016-01-01

    Sensor data fusion plays an important role in fault diagnosis. Dempster–Shafer (D-R) evidence theory is widely used in fault diagnosis, since it is efficient to combine evidence from different sensors. However, under the situation where the evidence highly conflicts, it may obtain a counterintuitive result. To address the issue, a new method is proposed in this paper. Not only the statistic sensor reliability, but also the dynamic sensor reliability are taken into consideration. The evidence distance function and the belief entropy are combined to obtain the dynamic reliability of each sensor report. A weighted averaging method is adopted to modify the conflict evidence by assigning different weights to evidence according to sensor reliability. The proposed method has better performance in conflict management and fault diagnosis due to the fact that the information volume of each sensor report is taken into consideration. An application in fault diagnosis based on sensor fusion is illustrated to show the efficiency of the proposed method. The results show that the proposed method improves the accuracy of fault diagnosis from 81.19% to 89.48% compared to the existing methods. PMID:26797611

  9. Modeling Sensor Reliability in Fault Diagnosis Based on Evidence Theory.

    PubMed

    Yuan, Kaijuan; Xiao, Fuyuan; Fei, Liguo; Kang, Bingyi; Deng, Yong

    2016-01-01

    Sensor data fusion plays an important role in fault diagnosis. Dempster-Shafer (D-R) evidence theory is widely used in fault diagnosis, since it is efficient to combine evidence from different sensors. However, under the situation where the evidence highly conflicts, it may obtain a counterintuitive result. To address the issue, a new method is proposed in this paper. Not only the statistic sensor reliability, but also the dynamic sensor reliability are taken into consideration. The evidence distance function and the belief entropy are combined to obtain the dynamic reliability of each sensor report. A weighted averaging method is adopted to modify the conflict evidence by assigning different weights to evidence according to sensor reliability. The proposed method has better performance in conflict management and fault diagnosis due to the fact that the information volume of each sensor report is taken into consideration. An application in fault diagnosis based on sensor fusion is illustrated to show the efficiency of the proposed method. The results show that the proposed method improves the accuracy of fault diagnosis from 81.19% to 89.48% compared to the existing methods. PMID:26797611

  10. Gas sensor array based on metal-decorated carbon nanotubes.

    PubMed

    Star, Alexander; Joshi, Vikram; Skarupo, Sergei; Thomas, David; Gabriel, Jean-Christophe P

    2006-10-26

    Here we demonstrate design, fabrication, and testing of electronic sensor array based on single-walled carbon nanotubes (SWNTs). Multiple sensor elements consisting of isolated networks of SWNTs were integrated into Si chips by chemical vapor deposition (CVD) and photolithography processes. For chemical selectivity, SWNTs were decorated with metal nanoparticles. The differences in catalytic activity of 18 catalytic metals for detection of H(2), CH(4), CO, and H(2)S gases were observed. Furthermore, a sensor array was fabricated by site-selective electroplating of Pd, Pt, Rh, and Au metals on isolated SWNT networks located on a single chip. The resulting electronic sensor array, which was comprised of several functional SWNT network sensors, was exposed to a randomized series of toxic/combustible gases. Electronic responses of all sensor elements were recorded and the sensor array data was analyzed using pattern-recognition analysis tools. Applications of these small-size, low-power, electronic sensor arrays are in the detection and identification of toxic/combustible gases for personal safety and air pollution monitoring. PMID:17048920

  11. Long-term monitoring FBG-based cable load sensor

    NASA Astrophysics Data System (ADS)

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

    2006-03-01

    Stay cables are the main load-bearing components of stayed-cable bridges. The cables stress status is an important factor to the stayed-cable bridge structure safety evaluation. So it's very important not only to the bridge construction, but also to the long-term safety evaluation for the bridge structure in-service. The accurate measurement for cable load depends on an effective sensor, especially to meet the long time durability and measurement demand. FBG, for its great advantage of corrosion resistance, absolute measurement, high accuracy, electro-magnetic resistance, quasi-distribution sensing, absolute measurement and so on, is the most promising sensor, which can cater for the cable force monitoring. In this paper, a load sensor has been developed, which is made up of a bushing elastic supporting body, 4 FBGs uniformly-spaced attached outside of the bushing supporting body, and a temperature compensation FBG for other four FBGs, moreover a cover for protection of FBGs. Firstly, the sensor measuring principle is analyzed, and relationship equation of FBG wavelength shifts and extrinsic load has also been gotten. And then the sensor calibration experiments of a steel cable stretching test with the FBG load sensor and a reference electric pressure sensor is finished, and the results shows excellent linearity of extrinsic load and FBG wavelength shifts, and good repeatability, which indicates that such kind of FBG-based load sensor is suitable for load measurement, especially for long-term, real time monitoring of stay-cables.

  12. Rational Design of QCM-D Virtual Sensor Arrays Based on Film Thickness, Viscoelasticity, and Harmonics for Vapor Discrimination.

    PubMed

    Speller, Nicholas C; Siraj, Noureen; Regmi, Bishnu P; Marzoughi, Hassan; Neal, Courtney; Warner, Isiah M

    2015-01-01

    Herein, we demonstrate an alternative strategy for creating QCM-based sensor arrays by use of a single sensor to provide multiple responses per analyte. The sensor, which simulates a virtual sensor array (VSA), was developed by depositing a thin film of ionic liquid, either 1-octyl-3-methylimidazolium bromide ([OMIm][Br]) or 1-octyl-3-methylimidazolium thiocyanate ([OMIm][SCN]), onto the surface of a QCM-D transducer. The sensor was exposed to 18 different organic vapors (alcohols, hydrocarbons, chlorohydrocarbons, nitriles) belonging to the same or different homologous series. The resulting frequency shifts (Δf) were measured at multiple harmonics and evaluated using principal component analysis (PCA) and discriminant analysis (DA) which revealed that analytes can be classified with extremely high accuracy. In almost all cases, the accuracy for identification of a member of the same class, that is, intraclass discrimination, was 100% as determined by use of quadratic discriminant analysis (QDA). Impressively, some VSAs allowed classification of all 18 analytes tested with nearly 100% accuracy. Such results underscore the importance of utilizing lesser exploited properties that influence signal transduction. Overall, these results demonstrate excellent potential of the virtual sensor array strategy for detection and discrimination of vapor phase analytes utilizing the QCM. To the best of our knowledge, this is the first report on QCM VSAs, as well as an experimental sensor array, that is based primarily on viscoelasticity, film thickness, and harmonics. PMID:25913394

  13. Analysis of Vehicle Detection with WSN-Based Ultrasonic Sensors

    PubMed Central

    Jo, Youngtae.; Jung, Inbum.

    2014-01-01

    Existing traffic information acquisition systems suffer from high cost and low scalability. To address these problems, the application of wireless sensor networks (WSNs) has been studied, as WSN-based systems are highly scalable and have a low cost of installing and replacing the systems. Magnetic, acoustic and accelerometer sensors have been considered for WSN-based traffic surveillance, but the use of ultrasonic sensors has not been studied. The limitations of WSN-based systems make it necessary to employ power saving methods and vehicle detection algorithms with low computational complexity. In this paper, we model and analyze optimal power saving methodologies for an ultrasonic sensor and present a computationally-efficient vehicle detection algorithm using ultrasonic data. The proposed methodologies are implemented and evaluated with a tiny microprocessor on real roads. The evaluation results show that the low computational complexity of our algorithm does not compromise the accuracy of vehicle detection. PMID:25093342

  14. Assessment of Exposure to Alcohol Vapor from Alcohol-Based Hand Rubs

    PubMed Central

    Bessonneau, Vincent; Thomas, Olivier

    2012-01-01

    This study assessed the inhaled dose of alcohol during hand disinfection. Experiments were conducted with two types of hand rub using two hand disinfection procedures. Air samples were collected every 10 s from the breathing zone, by bubbling through a mixture of K2Cr2O7 and H2SO4. The reduction of dichromate ions in the presence of alcohols was followed by UV-vis spectrophotometry. The difference in intensity of the dichromate absorption peak was used to quantify the alcohol concentration expressed in ethanol equivalent. During hygienic hand disinfection, the mean ethanol equivalent concentrations peaked at around 20–30 s for both hand rubs (14.3 ± 1.4 mg/L for hand rub 1 and 13.2 ± 0.7 mg/L for hand rub 2). During surgical hand disinfection, two peaks were found at the same time (40 and 80 s) for both hand rubs. The highest mean concentrations were 20.2 ± 0.9 mg/L for hand rub 1 and 18.1 ± 0.9 mg/L for hand rub 2. For hand rub 1, the total absorbed doses, calculated from ethanol with an inhalation flow of 24 L/min and an absorption rate of 62%, were 46.5 mg after one hygienic hand disinfection and 203.9 mg after one surgical hand disinfection. Although the use of ABHRs leads to the absorption of very low doses, sudden, repeated inhalation of high alcohol concentrations raises the question of possible adverse health effects. PMID:22690169

  15. Nanomaterial Based Sensors for NASA Missions

    NASA Technical Reports Server (NTRS)

    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.

  16. Enzyme-Based Fiber Optic Sensors

    NASA Astrophysics Data System (ADS)

    Kulp, Thomas J.; Camins, Irene; Angel, Stanley M.

    1988-06-01

    Fiber optic chemical sensors capable of detecting glucose and penicillin were developed. Each consists of a polymer membrane that is covalently attached to the tip of a glass optical fiber. The membrane contains the enzyme and a pH-sensitive fluorescent dye (fluorescein). A signal is produced when the enzyme catalyzes the conversion of the analyte (glucose or penicillin) into a product (gluconic or penicilloic acid, respectively) that lowers the microenvironmental pH of the membrane and, consequently, lowers the fluorescence intensity of the dye. Each sensor is capable of responding to analyte concentrations in the range of ~0.1 to 100 mM. The penicillin optrode response time is 40 to 60 s while that for glucose is ~5 to 12 min.

  17. Enzyme-based fiber optic sensors

    SciTech Connect

    Kulp, T.J.; Camins, I.; Angel, S.M.

    1987-12-01

    Fiber optic chemical sensors capable of detecting glucose and penicillin were developed. Each consists of a polymer membrane that is covalently attached to the tip of a glass optical fiber. The membrane contains the enzyme and a pH-sensitive fluorescent dye (fluorescein). A signal is produced when the enzyme catalyzes the conversion of the analyte (glucose or penicillin) into a product (gluconic or penicilloic acid, respectively) that lowers the microenvironmental pH of the membrane and consequently, lowers the fluorescence intensity of the dye. Each sensor is capable of responding to analyte concentrations in the range of approx.0.1 to 100 mM. The penicillin optrode response time is 40 to 60 s while that for glucose is approx.5 to 12 min. 7 figs.

  18. Sensor-fusion-based biometric identity verification

    SciTech Connect

    Carlson, J.J.; Bouchard, A.M.; Osbourn, G.C.; Martinez, R.F.; Bartholomew, J.W.; Jordan, J.B.; Flachs, G.M.; Bao, Z.; Zhu, L.

    1998-02-01

    Future generation automated human biometric identification and verification will require multiple features/sensors together with internal and external information sources to achieve high performance, accuracy, and reliability in uncontrolled environments. The primary objective of the proposed research is to develop a theoretical and practical basis for identifying and verifying people using standoff biometric features that can be obtained with minimal inconvenience during the verification process. The basic problem involves selecting sensors and discovering features that provide sufficient information to reliably verify a person`s identity under the uncertainties caused by measurement errors and tactics of uncooperative subjects. A system was developed for discovering hand, face, ear, and voice features and fusing them to verify the identity of people. The system obtains its robustness and reliability by fusing many coarse and easily measured features into a near minimal probability of error decision algorithm.

  19. Evaluating Community Readiness to Implement Environmental and Policy-Based Alcohol Abuse Prevention Strategies in Wisconsin

    ERIC Educational Resources Information Center

    Paltzer, Jason; Black, Penny; Moberg, D. Paul

    2013-01-01

    Background: Matching evidence-based alcohol prevention strat- egies with a community's readiness to support those strategies is the basis for the Tri-Ethnic Community Readiness Model (CRM). The purpose of this evaluation was to assess the association of a community's readiness to address alcohol abuse in their community with the…

  20. Influencing Adolescent Social Perceptions of Alcohol Use to Facilitate Change through a School-Based Intervention

    ERIC Educational Resources Information Center

    Schulte, Marya T.; Monreal, Teresa K.; Kia-Keating, Maryam; Brown, Sandra A.

    2010-01-01

    The current study examines the effectiveness of a voluntary high school-based alcohol intervention by investigating one proposed mechanism of change in adolescent alcohol involvement: perception of peer use. High school students reporting lifetime drinking (N = 2055) completed fall and spring surveys that assessed demographic information,…

  1. Evidence-Based Practice Guidelines for Fetal Alcohol Spectrum Disorder and Literacy and Learning

    ERIC Educational Resources Information Center

    Mitten, H. Rae

    2013-01-01

    Evidence-based Practice Guidelines for Fetal Alcohol Spectrum Disorder (FASD) and Literacy and Learning are derived from an inductive analysis of qualitative data collected in field research. FASD is the umbrella term for a spectrum of neurocognitive and physical disabilities caused by prenatal exposure to alcohol. Data from a sample of N=150 was…

  2. Evidence-Based Practice Guidelines for Fetal Alcohol Spectrum Disorder and Literacy and Learning

    ERIC Educational Resources Information Center

    Mitten, H. Rae

    2013-01-01

    Evidence-based Practice Guidelines for Fetal Alcohol Spectrum Disorder (FASD) and Literacy and Learning are derived from an inductive analysis of qualitative data collected in field research. FASD is the umbrella term for a spectrum of neurocognitive and physical disabilities caused by prenatal exposure to alcohol. Data from a sample of N =150 was…

  3. 78 FR 9938 - Ethyl Alcohol for Fuel Use: Determination of the Base Quantity of Imports

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-12

    ... recent previous determination for the 2012 amount in the Federal Register on December 30, 2011 (76 FR... COMMISSION Ethyl Alcohol for Fuel Use: Determination of the Base Quantity of Imports AGENCY: United States... is equal to 7 percent of the U.S. domestic market for fuel ethyl alcohol during the 12-month...

  4. Predictive Models of Alcohol Use Based on Attitudes and Individual Values

    ERIC Educational Resources Information Center

    Del Castillo Rodríguez, José A. García; López-Sánchez, Carmen; Soler, M. Carmen Quiles; Del Castillo-López, Álvaro García; Pertusa, Mónica Gázquez; Campos, Juan Carlos Marzo; Inglés, Cándido J.

    2013-01-01

    Two predictive models are developed in this article: the first is designed to predict people' attitudes to alcoholic drinks, while the second sets out to predict the use of alcohol in relation to selected individual values. University students (N = 1,500) were recruited through stratified sampling based on sex and academic discipline. The…

  5. Long period grating-based ocean pH sensor in an SMS fiber

    NASA Astrophysics Data System (ADS)

    Wang, Ke; Klimov, Denis; Kolber, Zbigniew

    2008-03-01

    A long period grating-based pH sensor has been designed in order to measure the pH in the ocean. The pH-sensitive hydrogel, which is made through the thermal crosslink of poly vinyl alcohol and poly acrylic acid, can swell or contract in response to the pH change in the surrounding environment. The sensor is designed in a single mode-multimode-single mode (SMS) fiber structure. The long period grating is written into the multimode fiber of the SMS structure using a focused CO II laser at the critical period (1 mm) of this particular multimode fiber. The hydrogel is glued underneath the SMS structure and will physically stretch or compress the long period grating hence change the phase matching condition in the SMS structure. Because of the different core sizes of the single mode fiber and the multimode fiber, only energy coupled in and out of the fundamental mode in the multimode fiber will be detected directly. The SMS structure has a higher sensitivity than using just the multimode sensing fiber. This sensor has been utilized in the seawater pH sensing in the range of 6 ~ 8. Experiments show that the sensor has a pH resolution of 0.0042.

  6. Trait-based affective processes in alcohol-involved "risk behaviors".

    PubMed

    Wray, Tyler B; Simons, Jeffrey S; Dvorak, Robert D; Gaher, Raluca M

    2012-11-01

    This study tested a theoretical model of alcohol use, markers of extreme intoxication, and risk behavior as a function of trait affect, distress tolerance, and affect-based behavior dysregulation. Positive affective pathways to risk behavior were primarily expected to be indirect via high levels of alcohol use, while negative affect paths were expected to be more directly associated with engagement in risk behavior. In addition, we expected trait affectivity and distress tolerance would primarily exhibit relationships with alcohol use and problems through behavioral dysregulation occurring during extreme affective states. To evaluate these hypotheses, we tested a SEM with three alcohol-related outcomes: "Typical" alcohol use, "blackout" drinking, and risk behavior. High trait negative affect and low tolerance for affective distress contribute to difficulty controlling behavior when negatively aroused and this is directly associated with increased risk behavior when drinking. In contrast, associations between positive urgency and risk behaviors are indirect via increased alcohol consumption. Positive affectivity exhibited both inverse and positive effects in the model, with the net effect on alcohol outcomes being insignificant. These findings contribute important information about the distinct pathways between affect, alcohol use, and alcohol-involved risk behavior among college students. PMID:22770825

  7. Bottlenecks of the wavefront sensor based on the Talbot effect.

    PubMed

    Podanchuk, Dmytro; Kovalenko, Andrey; Kurashov, Vitalij; Kotov, Myhaylo; Goloborodko, Andrey; Danko, Volodymyr

    2014-04-01

    Physical constraints and peculiarities of the wavefront sensing technique, based on the Talbot effect, are discussed. The limitation on the curvature of the measurable wavefront is derived. The requirements to the Fourier spectrum of the periodic mask are formulated. Two kinds of masks are studied for their performance in the wavefront sensor. It is shown that the boundary part of the mask aperture does not contribute to the initial data for wavefront restoration. It is verified by experiment and computer simulation that the performance of the Talbot sensor, which meets established conditions, is similar to that of the Shack-Hartmann sensor. PMID:24787208

  8. Nanotechnology-Based Electrochemical Sensors for Biomonitoring Chemical Exposures

    SciTech Connect

    Barry, Richard C.; Lin, Yuehe; Wang, Jun; Liu, Guodong; Timchalk, Charles

    2009-01-01

    This manuscript highlights research focused on the development of field-deployable analytical instruments based on EC detection. Background information and a general overview of EC detection methods and integrated use of nanomaterials in the development of these sensors are provided. New developments in EC sensors using various types of screen-printed electrodes, integrated nanomaterials, and immunoassays are discussed. Recent applications of EC sensors for assessing exposure to pesticides or detecting biomarkers of disease are highlighted to demonstrate the ability to monitor chemical metabolites, enzyme activity, or protein biomarkers of disease. In addition, future considerations and opportunities for advancing the use of EC platforms for dosimetric studies are covered.

  9. Microfluidic sensor based on integrated optical hollow waveguides.

    PubMed

    Campopiano, Stefania; Bernini, Romeo; Zeni, Luigi; Sarro, Pasqualina M

    2004-08-15

    A simple integrated optical refractometric sensor based on hollow-core antiresonant reflecting optical waveguides is proposed. The sensor uses the antiresonant reflecting guidance mechanism and permits one to measure the refractive index of a liquid filling the core by simply monitoring the transmitted spectrum. The device has been made with standard silicon technology, and the experimental results confirm numerical simulations performed in one- and two-dimensional geometry. The sensor exhibits a linear response over a wide measurement range (1.3330-1.4450) and a resolution of 9 x 10(-4) and requires a small analyte volume. PMID:15357351

  10. Compact IR laser for calibration of space based sensors

    SciTech Connect

    Kietrick, K.M.; Dezenberg, G.; Hamilton, C.; Vann, J.; LaSala, J.

    1996-04-17

    An Er:YAG laser, operating at 2.94 microns, has been developed for in-theater calibration of space based infrared sensors. The laser is used to illuminate a spaceborne sensor focal plane from a surveyed ground reference point. The known reference point is compared to the laser position reported by the sensor, and boresight corrections are made. The Er:YAG laser is side pumped by a InGaAs diode array and is tuned to an atmospheric microwindow with and intracavity etalon. This technology is being directly applied to meet Army requirements for enhanced deep strike targeting information supplied to theater weapons systems.

  11. Response analysis of holography-based modal wavefront sensor.

    PubMed

    Dong, Shihao; Haist, Tobias; Osten, Wolfgang; Ruppel, Thomas; Sawodny, Oliver

    2012-03-20

    The crosstalk problem of holography-based modal wavefront sensing (HMWS) becomes more severe with increasing aberration. In this paper, crosstalk effects on the sensor response are analyzed statistically for typical aberrations due to atmospheric turbulence. For specific turbulence strength, we optimized the sensor by adjusting the detector radius and the encoded phase bias for each Zernike mode. Calibrated response curves of low-order Zernike modes were further utilized to improve the sensor accuracy. The simulation results validated our strategy. The number of iterations for obtaining a residual RMS wavefront error of 0.1λ is reduced from 18 to 3. PMID:22441478

  12. Transparent and flexible force sensor array based on optical waveguide.

    PubMed

    Kim, Youngsung; Park, Suntak; Park, Seung Koo; Yun, Sungryul; Kyung, Ki-Uk; Sun, Kyung

    2012-06-18

    This paper suggests a force sensor array measuring contact force based on intensity change of light transmitted throughout optical waveguide. For transparency and flexibility of the sensor, two soft prepolymers with different refractive index have been developed. The optical waveguide consists of two cladding layers and a core layer. The top cladding layer is designed to allow light scattering at the specific area in response to finger contact. The force sensor shows a distinct tendency that output intensity decreases with input force and measurement range is from 0 to -13.2 dB. PMID:22714510

  13. The contributions of value-based decision-making and attentional bias to alcohol-seeking following devaluation

    PubMed Central

    Rose, Abigail K; Brown, Kyle; Field, Matt; Hogarth, Lee

    2013-01-01

    Aims To investigate the mediating role of attentional bias for alcohol cues on alcohol-seeking following devaluation of alcohol. Design Between subject. Setting Eye-tracking laboratory at the University of Liverpool. Participants Student social drinkers (n = 64). Measurements An operant choice task in which participants chose between simultaneously presented alcohol and non-alcohol drink rewards, while attentional bias for alcohol and non-alcohol drink cues was inferred from eye movements. Participants then consumed 30 mL of an alcoholic beverage, which was either presented alone (no devaluation: n = 32) or had been adulterated to taste unpleasant (devaluation: n = 32). Choice and attentional bias for the alcohol and non-alcohol drink pictures were then measured again. Findings Alcohol devaluation reduced behavioural choice for alcohol (F = 32.64, P < 0.001) and attentional bias for the alcohol pictures indexed by dwell time (F = 22.68, P < 0.001), initial fixation (F = 7.08, P = 0.01) and final fixation (F = 22.44, P < 0.001). Mediation analysis revealed that attentional bias partially mediated the effect of devaluation on alcohol choice; however, the proportion of the variance accounted for by attentional bias is low to moderate (∼30%). Conclusions Among student social drinkers, attentional bias is only a partial mediator of alcohol choice following devaluation of alcohol. Value-based decision-making may be a more important determinant of drinking behaviour among student social drinkers than attentional bias. PMID:23614520

  14. Sensor Systems Based on FPGAs and Their Applications: A Survey

    PubMed Central

    de la Piedra, Antonio; Braeken, An; Touhafi, Abdellah

    2012-01-01

    In this manuscript, we present a survey of designs and implementations of research sensor nodes that rely on FPGAs, either based upon standalone platforms or as a combination of microcontroller and FPGA. Several current challenges in sensor networks are distinguished and linked to the features of modern FPGAs. As it turns out, low-power optimized FPGAs are able to enhance the computation of several types of algorithms in terms of speed and power consumption in comparison to microcontrollers of commercial sensor nodes. We show that architectures based on the combination of microcontrollers and FPGA can play a key role in the future of sensor networks, in fields where processing capabilities such as strong cryptography, self-testing and data compression, among others, are paramount.

  15. SERS-based pesticide detection by using nanofinger sensors

    NASA Astrophysics Data System (ADS)

    Kim, Ansoon; Barcelo, Steven J.; Li, Zhiyong

    2015-01-01

    Simple, sensitive, and rapid detection of trace levels of extensively used and highly toxic pesticides are in urgent demand for public health. Surface-enhanced Raman scattering (SERS)-based sensor was designed to achieve ultrasensitive and simple pesticide sensing. We developed a portable sensor system composed of high performance and reliable gold nanofinger sensor strips and a custom-built portable Raman spectrometer. Compared to the general procedure and previously reported studies that are limited to laboratory settings, our analytical method is simple, sensitive, rapid, and cost-effective. Based on the SERS results, the chemical interaction of two pesticides, chlorpyrifos (CPF) and thiabendazole (TBZ), with gold nanofingers was studied to determine a fingerprint for each pesticide. The portable SERS-sensor system was successfully demonstrated to detect CPF and TBZ pesticides within 15 min with a detection limit of 35 ppt in drinking water and 7 ppb on apple skin, respectively.

  16. RESTFul based heterogeneous Geoprocessing workflow interoperation for Sensor Web Service

    NASA Astrophysics Data System (ADS)

    Yang, Chao; Chen, Nengcheng; Di, Liping

    2012-10-01

    Advanced sensors on board satellites offer detailed Earth observations. A workflow is one approach for designing, implementing and constructing a flexible and live link between these sensors' resources and users. It can coordinate, organize and aggregate the distributed sensor Web services to meet the requirement of a complex Earth observation scenario. A RESTFul based workflow interoperation method is proposed to integrate heterogeneous workflows into an interoperable unit. The Atom protocols are applied to describe and manage workflow resources. The XML Process Definition Language (XPDL) and Business Process Execution Language (BPEL) workflow standards are applied to structure a workflow that accesses sensor information and one that processes it separately. Then, a scenario for nitrogen dioxide (NO2) from a volcanic eruption is used to investigate the feasibility of the proposed method. The RESTFul based workflows interoperation system can describe, publish, discover, access and coordinate heterogeneous Geoprocessing workflows.

  17. Flexible textile-based strain sensor induced by contacts

    NASA Astrophysics Data System (ADS)

    Zhang, Hui

    2015-10-01

    In this paper, the contact effects are used as the key sensing element to develop flexible textile-structured strain sensors. The structures of the contact are analyzed theoretically and the contact resistances are investigated experimentally. The electromechanical properties of the textiles are investigated to find the key factors which determine the sensitivity, repeatability, and linearity of the sensor. The sensing mechanism is based on the change of contact resistance induced by the change of the configuration of the textiles. In order to improve the performance of the textile strain sensor, the contact resistance is designed based on the electromechanical properties of the fabric. It can be seen from the results that the performance of the sensor is largely affected by the structure of the contacts, which are determined by the morphology of fiber surface and the structures of the yarn and fabric.

  18. A High Temperature Capacitive Humidity Sensor Based on Mesoporous Silica

    PubMed Central

    Wagner, Thorsten; Krotzky, Sören; Weiß, Alexander; Sauerwald, Tilman; Kohl, Claus-Dieter; Roggenbuck, Jan; Tiemann, Michael

    2011-01-01

    Capacitive sensors are the most commonly used devices for the detection of humidity because they are inexpensive and the detection mechanism is very specific for humidity. However, especially for industrial processes, there is a lack of dielectrics that are stable at high temperature (>200 °C) and under harsh conditions. We present a capacitive sensor based on mesoporous silica as the dielectric in a simple sensor design based on pressed silica pellets. Investigation of the structural stability of the porous silica under simulated operating conditions as well as the influence of the pellet production will be shown. Impedance measurements demonstrate the utility of the sensor at both low (90 °C) and high (up to 210 °C) operating temperatures. PMID:22163790

  19. Torque Sensor Based on Tunnel-Diode Oscillator

    NASA Technical Reports Server (NTRS)

    Chui, Talso; Young, Joseph

    2008-01-01

    A proposed torque sensor would be capable of operating over the temperature range from 1 to 400 K, whereas a typical commercially available torque sensor is limited to the narrower temperature range of 244 to 338 K. The design of this sensor would exploit the wide temperature range and other desirable attributes of differential transducers based on tunnel-diode oscillators as described in "Multiplexing Transducers Based on Tunnel-Diode Oscillators". The proposed torque sensor would include three flexural springs that would couple torque between a hollow outer drive shaft and a solid inner drive shaft. The torque would be deduced from the torsional relative deflection of the two shafts, which would be sensed via changes in capacitances of two capacitors defined by two electrodes attached to the inner shaft and a common middle electrode attached to the outer shaft.

  20. Evidence-based alcohol policy in the Americas: strengths, weaknesses, and future challenges.

    PubMed

    Babor, Thomas F; Caetano, Raul

    2005-01-01

    The objectives of this article are to describe the evidence base for alcohol policy in the Americas, to evaluate the extent to which national policies are likely to have an impact on public health, and to identify areas where alcohol policies could be improved. The paper begins with a brief review of epidemiological surveys of the prevalence of alcohol problems in the Americas. This is followed by an analysis of 32 prevention strategies and interventions in terms of the evidence for their effectiveness, amount of research support, cost to implement, and other feasibility issues. Overall, the strategies and interventions with the greatest amount of empirical support are low blood alcohol concentration levels for driving while intoxicated, controls on alcohol availability, age limits on alcohol purchases, and relatively high alcohol prices. The implications of the evidence are next discussed in relation to alcohol policy initiatives in the Americas, based on an analysis of the extent to which strategies and interventions currently used in 25 countries of the Americas are likely to have a public health impact on alcohol-related problems. The countries that have adopted the policies with the highest expected impact overall are Colombia, Costa Rica, Venezuela, and El Salvador. Nevertheless, the analysis indicates that almost all the countries of the Americas could improve the likelihood of preventing alcohol-related problems. Policy efforts in the developing countries of Latin America should focus on improving countermeasures against driving while intoxicated, measures that alter the drinking context, and limits on physical availability. For the developed, high-income countries of North America the goal should be to prevent deterioration of current drinking patterns and to reduce the overall volume of drinking. Given the low to moderate cost of many of the policies reviewed in this article, it now seems possible for communities and nations to substantially reduce the

  1. Molecularly Imprinted Polymer Based Sensor for the Detection of Theophylline

    NASA Astrophysics Data System (ADS)

    Braga, Guilherme S.; Paterno, Leonardo G.; Fonseca, Fernando J.; del Valle, Manel

    2011-11-01

    A molecularly imprinted polymer (MIP) impedance-based sensor was employed to detect theophylline in distilled water. To evaluate its sensibility, impedance measurements were carried out in a diluted solution of theophylline (1 mM) and distilled water using MIP and NIP (reference non-imprinted polymer) sensors. MIP showed higher sensitivity to theophylline than the NIP. This feature shows their suitability for developing an electronic tongue system for determination of methylxanthines.

  2. Zone-Based Routing Protocol for Wireless Sensor Networks

    PubMed Central

    Venkateswarlu Kumaramangalam, Muni; Adiyapatham, Kandasamy; Kandasamy, Chandrasekaran

    2014-01-01

    Extensive research happening across the globe witnessed the importance of Wireless Sensor Network in the present day application world. In the recent past, various routing algorithms have been proposed to elevate WSN network lifetime. Clustering mechanism is highly successful in conserving energy resources for network activities and has become promising field for researches. However, the problem of unbalanced energy consumption is still open because the cluster head activities are tightly coupled with role and location of a particular node in the network. Several unequal clustering algorithms are proposed to solve this wireless sensor network multihop hot spot problem. Current unequal clustering mechanisms consider only intra- and intercluster communication cost. Proper organization of wireless sensor network into clusters enables efficient utilization of limited resources and enhances lifetime of deployed sensor nodes. This paper considers a novel network organization scheme, energy-efficient edge-based network partitioning scheme, to organize sensor nodes into clusters of equal size. Also, it proposes a cluster-based routing algorithm, called zone-based routing protocol (ZBRP), for elevating sensor network lifetime. Experimental results show that ZBRP out-performs interims of network lifetime and energy conservation with its uniform energy consumption among the cluster heads.

  3. Inertial Sensor-Based Gait Recognition: A Review.

    PubMed

    Sprager, Sebastijan; Juric, Matjaz B

    2015-01-01

    With the recent development of microelectromechanical systems (MEMS), inertial sensors have become widely used in the research of wearable gait analysis due to several factors, such as being easy-to-use and low-cost. Considering the fact that each individual has a unique way of walking, inertial sensors can be applied to the problem of gait recognition where assessed gait can be interpreted as a biometric trait. Thus, inertial sensor-based gait recognition has a great potential to play an important role in many security-related applications. Since inertial sensors are included in smart devices that are nowadays present at every step, inertial sensor-based gait recognition has become very attractive and emerging field of research that has provided many interesting discoveries recently. This paper provides a thorough and systematic review of current state-of-the-art in this field of research. Review procedure has revealed that the latest advanced inertial sensor-based gait recognition approaches are able to sufficiently recognise the users when relying on inertial data obtained during gait by single commercially available smart device in controlled circumstances, including fixed placement and small variations in gait. Furthermore, these approaches have also revealed considerable breakthrough by realistic use in uncontrolled circumstances, showing great potential for their further development and wide applicability. PMID:26340634

  4. Inertial Sensor-Based Gait Recognition: A Review

    PubMed Central

    Sprager, Sebastijan; Juric, Matjaz B.

    2015-01-01

    With the recent development of microelectromechanical systems (MEMS), inertial sensors have become widely used in the research of wearable gait analysis due to several factors, such as being easy-to-use and low-cost. Considering the fact that each individual has a unique way of walking, inertial sensors can be applied to the problem of gait recognition where assessed gait can be interpreted as a biometric trait. Thus, inertial sensor-based gait recognition has a great potential to play an important role in many security-related applications. Since inertial sensors are included in smart devices that are nowadays present at every step, inertial sensor-based gait recognition has become very attractive and emerging field of research that has provided many interesting discoveries recently. This paper provides a thorough and systematic review of current state-of-the-art in this field of research. Review procedure has revealed that the latest advanced inertial sensor-based gait recognition approaches are able to sufficiently recognise the users when relying on inertial data obtained during gait by single commercially available smart device in controlled circumstances, including fixed placement and small variations in gait. Furthermore, these approaches have also revealed considerable breakthrough by realistic use in uncontrolled circumstances, showing great potential for their further development and wide applicability. PMID:26340634

  5. Magnetic Sensors Based on Amorphous Ferromagnetic Materials: A Review.

    PubMed

    Morón, Carlos; Cabrera, Carolina; Morón, Alberto; García, Alfonso; González, Mercedes

    2015-01-01

    Currently there are many types of sensors that are used in lots of applications. Among these, magnetic sensors are a good alternative for the detection and measurement of different phenomena because they are a "simple" and readily available technology. For the construction of such devices there are many magnetic materials available, although amorphous ferromagnetic materials are the most suitable. The existence in the market of these materials allows the production of different kinds of sensors, without requiring expensive manufacture investments for the magnetic cores. Furthermore, these are not fragile materials that require special care, favouring the construction of solid and reliable devices. Another important feature is that these sensors can be developed without electric contact between the measuring device and the sensor, making them especially fit for use in harsh environments. In this review we will look at the main types of developed magnetic sensors. This work presents the state of the art of magnetic sensors based on amorphous ferromagnetic materials used in modern technology: security devices, weapon detection, magnetic maps, car industry, credit cards, etc. PMID:26569244

  6. Development of metamaterial based low cost passive wireless temperature sensor

    NASA Astrophysics Data System (ADS)

    Karim, Hasanul; Shuvo, Mohammad Arif Ishtiaq; Delfin, Diego; Lin, Yirong; Choudhuri, Ahsan; Rumpf, R. C.

    2014-03-01

    Wireless passive temperature sensors are gaining increasing attention due to the ever-growing need of precise monitoring of temperature in high temperature energy conversion systems such as gas turbines and coal-based power plants. Unfortunately, the harsh environment such as high temperature and corrosive atmosphere present in these systems limits current solutions. In order to alleviate these issues, this paper presents the design, simulation, and manufacturing process of a low cost, passive, and wireless temperature sensor that can withstand high temperature and harsh environment. The temperature sensor was designed following the principle of metamaterials by utilizing Closed Ring Resonators (CRR) embedded in a dielectric matrix. The proposed wireless, passive temperature sensor behaves like an LC circuit that has a resonance frequency that depends on temperature. A full wave electromagnetic solver Ansys Ansoft HFSS was used to perform simulations to determine the optimum dimensions and geometry of the sensor unit. The sensor unit was prepared by conventional powder-binder compression method. Commercially available metal washers were used as CRR structures and Barium Titanate (BTO) was used as the dielectric materials. Response of the fabricated sensor at room temperature was analyzed using a pair of horn antenna connected with a network analyzer.

  7. Automatic sensor placement for model-based robot vision.

    PubMed

    Chen, S Y; Li, Y F

    2004-02-01

    This paper presents a method for automatic sensor placement for model-based robot vision. In such a vision system, the sensor often needs to be moved from one pose to another around the object to observe all features of interest. This allows multiple three-dimensional (3-D) images to be taken from different vantage viewpoints. The task involves determination of the optimal sensor placements and a shortest path through these viewpoints. During the sensor planning, object features are resampled as individual points attached with surface normals. The optimal sensor placement graph is achieved by a genetic algorithm in which a min-max criterion is used for the evaluation. A shortest path is determined by Christofides algorithm. A Viewpoint Planner is developed to generate the sensor placement plan. It includes many functions, such as 3-D animation of the object geometry, sensor specification, initialization of the viewpoint number and their distribution, viewpoint evolution, shortest path computation, scene simulation of a specific viewpoint, parameter amendment. Experiments are also carried out on a real robot vision system to demonstrate the effectiveness of the proposed method. PMID:15369081

  8. Magnetic Sensors Based on Amorphous Ferromagnetic Materials: A Review

    PubMed Central

    Morón, Carlos; Cabrera, Carolina; Morón, Alberto; García, Alfonso; González, Mercedes

    2015-01-01

    Currently there are many types of sensors that are used in lots of applications. Among these, magnetic sensors are a good alternative for the detection and measurement of different phenomena because they are a “simple” and readily available technology. For the construction of such devices there are many magnetic materials available, although amorphous ferromagnetic materials are the most suitable. The existence in the market of these materials allows the production of different kinds of sensors, without requiring expensive manufacture investments for the magnetic cores. Furthermore, these are not fragile materials that require special care, favouring the construction of solid and reliable devices. Another important feature is that these sensors can be developed without electric contact between the measuring device and the sensor, making them especially fit for use in harsh environments. In this review we will look at the main types of developed magnetic sensors. This work presents the state of the art of magnetic sensors based on amorphous ferromagnetic materials used in modern technology: security devices, weapon detection, magnetic maps, car industry, credit cards, etc. PMID:26569244

  9. Silicon nanohybrid-based surface-enhanced Raman scattering sensors.

    PubMed

    Wang, Houyu; Jiang, Xiangxu; Lee, Shuit-Tong; He, Yao

    2014-11-01

    Nanomaterial-based surface-enhanced Raman scattering (SERS) sensors are highly promising analytical tools, capable of ultrasensitive, multiplex, and nondestructive detection of chemical and biological species. Extensive efforts have been made to design various silicon nanohybrid-based SERS substrates such as gold/silver nanoparticle (NP)-decorated silicon nanowires, Au/Ag NP-decorated silicon wafers (AuNP@Si), and so forth. In comparison to free AuNP- and AgNP-based SERS sensors, the silicon nanohybrid-based SERS sensors feature higher enhancement factors (EFs) and excellent reproducibility, since SERS hot spots are efficiently coupled and stabilized through interconnection to the semiconducting silicon substrates. Consequently, in the past decade, giant advancements in the development of silicon nanohybrid-based SERS sensors have been witnessed for myriad sensing applications. In this review, the representative achievements related to the design of high-performance silicon nanohybrid-based SERS sensors and their use for chemical and biological analysis are reviewed in a detailed way. Furthermore, the major opportunities and challenges in this field are discussed from a broad perspective and possible future directions. PMID:25243935

  10. Gas Sensors Based on Ceramic p-n Heterocontacts

    SciTech Connect

    Seymen Murat Aygun

    2004-12-19

    Ceramic p-n heterocontacts based on CuO/ZnO were successfully synthesized and a systematic study of their hydrogen sensitivity was conducted. The sensitivity and response rates of CuO/ZnO sensors were studied utilizing current-voltage, current-time, and impedance spectroscopy measurements. The heterocontacts showed well-defined rectifying characteristics and were observed to detect hydrogen via both dc and ac measurements. Surface coverage data were derived from current-time measurements which were then fit to a two-site Langmuir adsorption model quite satisfactorily. The fit suggested that there should be two energetically different adsorption sites in the system. The heterocontacts were doped in an attempt to increase the sensitivity and the response rate of the sensor. First, the effects of doping the p-type (CuO) on the sensor characteristics were investigated. Doping the p-type CuO with both acceptor and isovalent dopants greatly improved the hydrogen sensitivity. The sensitivity of pure heterocontact observed via I-V measurements was increased from {approx}2.3 to {approx}9.4 with Ni doping. Dopants also enhanced the rectifying characteristics of the heterocontacts. Small amounts of Li addition were shown to decrease the reverse bias (saturation) current to 0.2 mA at a bias level of -5V. No unambiguous trends were observed between the sensitivity, the conductivity, and the density of the samples. Comparing the two phase microstructure to the single phase microstructure there was no dramatic increase in the sensitivity. Kinetic studies also confirmed the improved sensor characteristics with doping. The dopants decreased the response time of the sensor by decreasing the response time of one of the adsorption sites. The n-type ZnO was doped with both acceptor and donor dopants. Li doping resulted in the degradation of the p-n junction and the response time of the sensor. However, the current-voltage behavior of Ga-doped heterocontacts showed the best rectifying

  11. The Influence of Alcohol-Related Cognitions on Personality-Based Risk for Alcohol Use during Adolescence

    ERIC Educational Resources Information Center

    Bekman, Nicole M.; Cummins, Kevin; Brown, Sandra A.

    2011-01-01

    This study examines whether expectancies about the impact of not drinking or reducing alcohol use and perceptions of peer alcohol use partially mediated risk incurred by sensation seeking for adolescent alcohol involvement. High school drinkers (N = 3,153) completed a survey assessing substance use, sensation seeking, perceived peer alcohol use,…

  12. Piezoresistive Strain Sensors Made from Carbon Nanotubes Based Polymer Nanocomposites

    PubMed Central

    Alamusi; Hu, Ning; Fukunaga, Hisao; Atobe, Satoshi; Liu, Yaolu; Li, Jinhua

    2011-01-01

    In recent years, nanocomposites based on various nano-scale carbon fillers, such as carbon nanotubes (CNTs), are increasingly being thought of as a realistic alternative to conventional smart materials, largely due to their superior electrical properties. Great interest has been generated in building highly sensitive strain sensors with these new nanocomposites. This article reviews the recent significant developments in the field of highly sensitive strain sensors made from CNT/polymer nanocomposites. We focus on the following two topics: electrical conductivity and piezoresistivity of CNT/polymer nanocomposites, and the relationship between them by considering the internal conductive network formed by CNTs, tunneling effect, aspect ratio and piezoresistivity of CNTs themselves, etc. Many recent experimental, theoretical and numerical studies in this field are described in detail to uncover the working mechanisms of this new type of strain sensors and to demonstrate some possible key factors for improving the sensor sensitivity. PMID:22346667

  13. Highly sensitive biological sensor based on photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Azzam, Shaimaa I. H.; Hameed, Mohamed F.; Obayya, S. S. A.

    2014-05-01

    A photonic crystal fiber (PCF) surface plasmon resonance (SPR) based sensor is proposed and analysed. The proposed sensor consists of microuidic slots enclosing a dodecagonal layer of air holes cladding and a central air hole. The sensor can perform analyte detection using both HEx 11 and HEy 11 modes with a relatively high sensitivities up to 4000 nm=RIU and 3000 nm=RIU and resolutions of 2.5×10-5 RIU-1 and 3.33×10-5 RIU-1 with HEx11 and HEy11, respectively, with regards to spectral interrogation which to our knowledge are higher than those reported in the literature. Moreover, the structure of the suggested sensor is simple with no fabrication complexities which makes it easy to fabricate with standard PCF fabrication technologies.

  14. Fiber optic sensor-based intelligent coal mines

    NASA Astrophysics Data System (ADS)

    Liu, T.; Wang, C.; Wei, Y.; Ni, J.; Li, Y.; Wang, Q.; Ma, L.; Shi, Z.; Liu, X.

    2007-07-01

    Fiber optic sensors have become increasingly attractive for application in advanced intelligent coal mines, which consist of extensive sensor network to monitor the structural integrity, environmental safety and production parameters. Fiber optic based strain (mining pressure), temperature, water pressure, methane gas, seismic and ultrasound sensors can be used to monitor the condition of the coal mine and provide information for accident prediction and early warning. We report for the first time an all fiber optic comprehensive coal mine safety monitoring system. The system is capable of methane gas monitoring, temperature monitoring, seismic event and mine pressure detection and water pressure monitoring. The advantages of this fiber optic sensor system include intrinsic safety in explosive environment and multiparameter monitoring. The technology potentially can be used to replace many discrete and incompatible monitoring systems currently deployed in the coal mines and consequently greatly enhance coal mine safety.

  15. An Architecture for Intelligent Systems Based on Smart Sensors

    NASA Technical Reports Server (NTRS)

    Schmalzel, John; Figueroa, Fernando; Morris, Jon; Mandayam, Shreekanth; Polikar, Robi

    2004-01-01

    Based on requirements for a next-generation rocket test facility, elements of a prototype Intelligent Rocket Test Facility (IRTF) have been implemented. A key component is distributed smart sensor elements integrated using a knowledgeware environment. One of the specific goals is to imbue sensors with the intelligence needed to perform self diagnosis of health and to participate in a hierarchy of health determination at sensor, process, and system levels. The preliminary results provide the basis for future advanced development and validation using rocket test stand facilities at Stennis Space Center (SSC). We have identified issues important to further development of health-enabled networks, which should be of interest to others working with smart sensors and intelligent health management systems.

  16. Piezoresistive strain sensors made from carbon nanotubes based polymer nanocomposites.

    PubMed

    Alamusi; Hu, Ning; Fukunaga, Hisao; Atobe, Satoshi; Liu, Yaolu; Li, Jinhua

    2011-01-01

    In recent years, nanocomposites based on various nano-scale carbon fillers, such as carbon nanotubes (CNTs), are increasingly being thought of as a realistic alternative to conventional smart materials, largely due to their superior electrical properties. Great interest has been generated in building highly sensitive strain sensors with these new nanocomposites. This article reviews the recent significant developments in the field of highly sensitive strain sensors made from CNT/polymer nanocomposites. We focus on the following two topics: electrical conductivity and piezoresistivity of CNT/polymer nanocomposites, and the relationship between them by considering the internal conductive network formed by CNTs, tunneling effect, aspect ratio and piezoresistivity of CNTs themselves, etc. Many recent experimental, theoretical and numerical studies in this field are described in detail to uncover the working mechanisms of this new type of strain sensors and to demonstrate some possible key factors for improving the sensor sensitivity. PMID:22346667

  17. A microring resonator based negative permeability metamaterial sensor.

    PubMed

    Sun, Jun; Huang, Ming; Yang, Jing-Jing; Li, Ting-Hua; Lan, Yao-Zhong

    2011-01-01

    Metamaterials are artificial multifunctional materials that acquire their material properties from their structure, rather than inheriting them directly from the materials they are composed of, and they may provide novel tools to significantly enhance the sensitivity and resolution of sensors. In this paper, we derive the dispersion relation of a cylindrical dielectric waveguide loaded on a negative permeability metamaterial (NPM) layer, and compute the resonant frequencies and electric field distribution of the corresponding Whispering-Gallery-Modes (WGMs). The theoretical resonant frequency and electric field distribution results are in good agreement with the full wave simulation results. We show that the NPM sensor based on a microring resonator possesses higher sensitivity than the traditional microring sensor since with the evanescent wave amplification and the increase of NPM layer thickness, the sensitivity will be greatly increased. This may open a door for designing sensors with specified sensitivity. PMID:22164062

  18. An improved sensor for electrochemical microcalorimetry, based on lithiumtantalate.

    PubMed

    Frittmann, Stefan; Halka, Vadym; Jaramillo, Carlos; Schuster, Rolf

    2015-06-01

    We have developed a pyroelectric sensor for electrochemical microcalorimetry, based on LiTaO3, which provides unprecedented sensitivity for the detection of electrochemically induced heat effects. Deterioration of the heat signal by electrostriction effects on the electrode surface is suppressed by a multilayered construction, where an intermediate sapphire sheet dampens mechanical deformations. Thus, well textured thin metal films become viable candidates as electrodes. We demonstrate the sensor performance for Cu underpotential deposition on (111)-textured Au films on sapphire. The sensor signal compares well with a purely thermal signal induced by heating with laser pulses. The high sensitivity of the sensor is demonstrated by measuring heat effects upon double layer charging in perchloric acid, i.e., in the absence of electrochemical charge- or ion-transfer reactions. PMID:26133850

  19. Electronic tongue based on an array of metallic potentiometric sensors.

    PubMed

    Lvova, Larisa; Martinelli, Eugenio; Mazzone, Emiliano; Pede, Andrea; Paolesse, Roberto; Di Natale, Corrado; D'Amico, Arnaldo

    2006-11-15

    An electronic tongue system based on the array of six metallic potentiometric sensors (metallic wires) was developed and utilized for discrimination of foodstuffs: several types of vinegar and fruit juices. Copper, tin, iron, aluminum, brass and stainless steel wires were included in the array and supplemented by pH glass electrode. The response of potentiometric metallic sensors towards various organic acids has been studied and possible sensitivity mechanisms were discussed. Overall potential changes of metallic sensors were exanimate as complex mixed signals influenced by several components presenting in analyte employing chemometric approach. The multisensor array of such a type can be useful for several applications since of simplicity in handling, low cost of sensors and easy measure procedure. PMID:18970847

  20. A flexible piezoelectric force sensor based on PVDF fabrics

    NASA Astrophysics Data System (ADS)

    Wang, Y. R.; Zheng, J. M.; Ren, G. Y.; Zhang, P. H.; Xu, C.

    2011-04-01

    Polyvinylidene fluoride (PVDF) film has been widely investigated as a sensor and transducer material due to its high piezo-, pyro- and ferroelectric properties. To activate these properties, PVDF films require a mechanical treatment, stretching or poling. In this paper, we report on a force sensor based on PVDF fabrics with excellent flexibility and breathability, to be used as a specific human-related sensor. PVDF nanofibrous fabrics were prepared by using an electrospinning unit and characterized by means of scanning electron microscopy (SEM), FTIR spectroscopy and x-ray diffraction. Preliminary force sensors have been fabricated and demonstrated excellent sensitivity and response to external mechanical forces. This implies that promising applications can be made for sensing garment pressure, blood pressure, heartbeat rate, respiration rate and accidental impact on the human body.

  1. Affinity sensor based on immobilized molecular imprinted synthetic recognition elements.

    PubMed

    Lenain, Pieterjan; De Saeger, Sarah; Mattiasson, Bo; Hedström, Martin

    2015-07-15

    An affinity sensor based on capacitive transduction was developed to detect a model compound, metergoline, in a continuous flow system. This system simulates the monitoring of low-molecular weight organic compounds in natural flowing waters, i.e. rivers and streams. During operation in such scenarios, control of the experimental parameters is not possible, which poses a true analytical challenge. A two-step approach was used to produce a sensor for metergoline. Submicron spherical molecularly imprinted polymers, used as recognition elements, were obtained through emulsion polymerization and subsequently coupled to the sensor surface by electropolymerization. This way, a robust and reusable sensor was obtained that regenerated spontaneously under the natural conditions in a river. Small organic compounds could be analyzed in water without manipulating the binding or regeneration conditions, thereby offering a viable tool for on-site application. PMID:25703726

  2. MEMS-based sensor arrays for military applications

    NASA Astrophysics Data System (ADS)

    Ruffin, Paul B.

    2002-07-01

    Scientists and engineers at the Army Aviation Missile Command's (AMCOM) Research, Development and Engineering Center (RDEC) are cooperatively working with the Defense Advanced Research Projects Agency (DARPA), other Army agencies, and industry to provide technical solutions for the Army's transformation efforts into the 21st Century force. Advanced technologies are being exposed to achieve the performance and cost goals dictated by the emerging missions of the Transformed Army. It is well established that MEMS technology offers the potential solution to cost, size, and weight issues for the soldier, missile, gun, ground vehicles, and aircraft applications. MEMS sensor arrays are currently being investigated to meet system performance requirements and provide more robust mission capability. A Science and Technology Objective, Research and Development Project is underway at AMCOM/RDEC to develop controlled MEMS sensor arrays to provide for full military dynamic performance ranges using miniature sensor system. MEMS-based angular rate sensors are enhanced with vibration feedback form MEMS accelerometers for output signal stabilization in high-vibration environments. Multi-range MEMS-based accelerometers, cooperatively developed by Government and industry, are being multiplexed to provide dynamic range expansion. An array of integrated accelerometers is expected to increase the dynamic range by an order of magnitude. Future projections suggest that MEMS sensor array technology will be applicable to a broad range of military applications, which include environmental sensor suites for structural health monitoring and forward reconnaissance and surveillance; and optical and radio frequency phased arrays for fast beam steering.

  3. Engineering new aptamer geometries for electrochemical aptamer-based sensors

    NASA Astrophysics Data System (ADS)

    White, Ryan J.; Plaxco, Kevin W.

    2009-05-01

    Electrochemical aptamer-based sensors (E-AB sensors) represent a promising new approach to the detection of small molecules. E-AB sensors comprise an aptamer that is attached at one end to an electrode surface. The distal end of the aptamer probed is modified with an electroactive redox marker for signal transduction. Herein we report on the optimization of a cocaine-detecting E-AB sensor via optimization of the geometry of the aptamer. We explore two new aptamer architectures, one in which we concatenate three cocaine aptamers into a poly-aptamer and a second in which we divide the cocaine aptamer into pieces connected via an unstructured, 60-thymine linker. Both of these structures are designed such that the reporting redox tag will be located farther from the electrode in the unfolded, target-free conformation. Consistent with this, we find that signal gains of these two constructs are two to three times higher than that of the original E-AB architecture. Likewise all three architectures are selective enough to deploy directly in complex sample matrices, such as undiluted whole blood, with all three sensors successfully detecting the presence of cocaine. The findings in this ongoing study should be of value in future efforts to optimize the signaling of electrochemical aptamer-based sensors.

  4. Energy Efficient Cluster Based Scheduling Scheme for Wireless Sensor Networks

    PubMed Central

    Srie Vidhya Janani, E.; Ganesh Kumar, P.

    2015-01-01

    The energy utilization of sensor nodes in large scale wireless sensor network points out the crucial need for scalable and energy efficient clustering protocols. Since sensor nodes usually operate on batteries, the maximum utility of network is greatly dependent on ideal usage of energy leftover in these sensor nodes. In this paper, we propose an Energy Efficient Cluster Based Scheduling Scheme for wireless sensor networks that balances the sensor network lifetime and energy efficiency. In the first phase of our proposed scheme, cluster topology is discovered and cluster head is chosen based on remaining energy level. The cluster head monitors the network energy threshold value to identify the energy drain rate of all its cluster members. In the second phase, scheduling algorithm is presented to allocate time slots to cluster member data packets. Here congestion occurrence is totally avoided. In the third phase, energy consumption model is proposed to maintain maximum residual energy level across the network. Moreover, we also propose a new packet format which is given to all cluster member nodes. The simulation results prove that the proposed scheme greatly contributes to maximum network lifetime, high energy, reduced overhead, and maximum delivery ratio. PMID:26495417

  5. APTAMER-BASED SERRS SENSOR FOR THROMBIN DETECTION

    SciTech Connect

    Cho, H; Baker, B R; Wachsmann-Hogiu, S; Pagba, C V; Laurence, T A; Lane, S M; Lee, L P; Tok, J B

    2008-07-02

    We describe an aptamer-based Surface Enhanced Resonance Raman Scattering (SERRS) sensor with high sensitivity, specificity, and stability for the detection of a coagulation protein, human a-thrombin. The sensor achieves high sensitivity and a limit of detection of 100 pM by monitoring the SERRS signal change upon the single step of thrombin binding to immobilized thrombin binding aptamer. The selectivity of the sensor is demonstrated by the specific discrimination of thrombin from other protein analytes. The specific recognition and binding of thrombin by the thrombin binding aptamer is essential to the mechanism of the aptamer-based sensor, as shown through measurements using negative control oligonucleotides. In addition, the sensor can detect 1 nM thrombin in the presence of complex biofluids, such as 10% fetal calf serum, demonstrating that the immobilized, 5{prime}-capped, 3{prime}-capped aptamer is sufficiently robust for clinical diagnostic applications. Furthermore, the proposed sensor may be implemented for multiplexed detection using different aptamer-Raman probe complexes.

  6. Disposable Copper-Based Electrochemical Sensor for Anodic Stripping Voltammetry

    PubMed Central

    2015-01-01

    In this work, we report the first copper-based point-of-care sensor for electrochemical measurements demonstrated by zinc determination in blood serum. Heavy metals require careful monitoring, yet current methods are too complex for a point-of-care system. Electrochemistry offers a simple approach to metal detection on the microscale, but traditional carbon, gold (Au), or platinum (Pt) electrodes are difficult or expensive to microfabricate, preventing widespread use. Our sensor features a new low-cost electrode material, copper, which offers simple fabrication and compatibility with microfabrication and PCB processing, while maintaining competitive performance in electrochemical detection. Anodic stripping voltammetry of zinc using our new copper-based sensors exhibited a 140 nM (9.0 ppb) limit of detection (calculated) and sensitivity greater than 1 μA/μM in the acetate buffer. The sensor was also able to determine zinc in a bovine serum extract, and the results were verified with independent sensor measurements. These results demonstrate the advantageous qualities of this lab-on-a-chip electrochemical sensor for clinical applications, which include a small sample volume (μL scale), reduced cost, short response time, and high accuracy at low concentrations of analyte. PMID:24773513

  7. Aptamer-based SERRS sensor for thrombin detection.

    PubMed

    Cho, Hansang; Baker, Brian R; Wachsmann-Hogiu, Sebastian; Pagba, Cynthia V; Laurence, Ted A; Lane, Stephen M; Lee, Luke P; Tok, Jeffrey B H

    2008-12-01

    We describe an aptamer-based surface enhanced resonance Raman scattering (SERRS) sensor with high sensitivity, specificity, and stability for the detection of a coagulation protein, human alpha-thrombin. The sensor achieves high sensitivity and a limit of detection of 100 pM by monitoring the SERRS signal change upon the single-step of thrombin binding to immobilized thrombin binding aptamer. The selectivity of the sensor is demonstrated by the specific discrimination of thrombin from other protein analytes. The specific recognition and binding of thrombin by the thrombin binding aptamer is essential to the mechanism of the aptamer-based sensor, as shown through measurements using negative control oligonucleotides. In addition, the sensor can detect 1 nM thrombin in the presence of complex biofluids, such as 10% fetal calf serum, demonstrating that the immobilized, 5'-capped, 3'-capped aptamer is sufficiently robust for clinical diagnostic applications. Furthermore, the proposed sensor may be implemented for multiplexed detection using different aptamer-Raman probe complexes. PMID:19367849

  8. Laser-based Sensors for Chemical Detection

    SciTech Connect

    Myers, Tanya L.; Phillips, Mark C.; Taubman, Matthew S.; Bernacki, Bruce E.; Schiffern, John T.; Cannon, Bret D.

    2010-05-10

    Stand-off detection of hazardous materials ensures that the responder is located at a safe distance from the suspected source. Remote detection and identification of hazardous materials can be accomplished using a highly sensitive and portable device, at significant distances downwind from the source or the threat. Optical sensing methods, in particular infrared absorption spectroscopy combined with quantum cascade lasers (QCLs), are highly suited for the detection of chemical substances since they enable rapid detection and are amenable for autonomous operation in a compact and rugged package. This talk will discuss the sensor systems developed at Pacific Northwest National Laboratory and will discuss the progress to reduce the size and power while maintaining sensitivity to enable stand-off detection of multiple chemicals.

  9. Antimicrobial efficacy of soap and water hand washing versus an alcohol-based hand cleanser.

    PubMed

    Holton, Ronald H; Huber, Michaell A; Terezhalmy, Geza T

    2009-12-01

    The emergence of alcohol-based hand cleansers may represent an alternative to soap and water in the clinical dental setting. In this study, the antimicrobial efficacy of traditional hand washing vs. a unique alcohol-based hand cleanser with persistence was evaluated. Two experienced dentists participated over a 10-day period. On days 1-5, each clinician used an antibacterial liquid soap (Dial, Dial Corporation, Scottsdale, AZ). Days 6-10, an alcohol-based hand cleanser (Triseptin Water Optional, Healthpoint Surgical, Fort Worth, TX) was used. Sampling was by modified glove juice technique. The results indicate that the alcohol-based hand cleanser dramatically outperforms the traditional hand washing agent in the general dental setting. PMID:20131613

  10. Optical sensor array platform based on polymer electronic devices

    NASA Astrophysics Data System (ADS)

    Koetse, Marc M.; Rensing, Peter A.; Sharpe, Ruben B. A.; van Heck, Gert T.; Allard, Bart A. M.; Meulendijks, Nicole N. M. M.; Kruijt, Peter G. M.; Tijdink, Marcel W. W. J.; De Zwart, René M.; Houben, René J.; Enting, Erik; van Veen, Sjaak J. J. F.; Schoo, Herman F. M.

    2007-10-01

    Monitoring of personal wellbeing and optimizing human performance are areas where sensors have only begun to be used. One of the reasons for this is the specific demands that these application areas put on the underlying technology and system properties. In many cases these sensors will be integrated in clothing, be worn on the skin, or may even be placed inside the body. This implies that flexibility and wearability of the systems is essential for their success. Devices based on polymer semiconductors allow for these demands since they can be fabricated with thin film technology. The use of thin film device technology allows for the fabrication of very thin sensors (e.g. integrated in food product packaging), flexible or bendable sensors in wearables, large area/distributed sensors, and intrinsically low-cost applications in disposable products. With thin film device technology a high level of integration can be achieved with parts that analyze signals, process and store data, and interact over a network. Integration of all these functions will inherently lead to better cost/performance ratios, especially if printing and other standard polymer technology such as high precision moulding is applied for the fabrication. In this paper we present an optical transmission sensor array based on polymer semiconductor devices made by thin film technology. The organic devices, light emitting diodes, photodiodes and selective medium chip, are integrated with classic electronic components. Together they form a versatile sensor platform that allows for the quantitative measurement of 100 channels and communicates wireless with a computer. The emphasis is given to the sensor principle, the design, fabrication technology and integration of the thin film devices.

  11. Trait-based Affective Processes in Alcohol-Involved Risk Behaviors

    PubMed Central

    Wray, Tyler B.; Simons, Jeffrey S.; Dvorak, Robert D.; Gaher, Raluca M.

    2012-01-01

    This study tested a theoretical model of alcohol use, markers of extreme intoxication, and risk behavior as a function of trait affect, distress tolerance, and affect-based behavior dysregulation. Positive affective pathways to risk behavior were primarily expected to be indirect via high levels of alcohol use, while negative affect paths were expected to be more directly associated with engagement in risk behavior. In addition, we expected trait affectivity and distress tolerance would primarily exhibit relationships with alcohol use and problems through behavioral dysregulation occurring during extreme affective states. To evaluate these hypotheses, we tested a SEM with three alcohol–related outcomes: “Typical” alcohol use, “blackout” drinking,” and risk behavior. Results were complex, but generally supported the hypotheses. High trait negative affect and low tolerance for affective distress contribute to difficulty controlling behavior when negatively aroused and this is directly associated with increased risk behavior when drinking. In contrast, associations between positive urgency and risk behaviors are indirect via increased alcohol consumption. Positive affectivity exhibited both inverse and positive effects in the model, with the net effect on alcohol outcomes being insignificant. These findings contribute important information about the distinct pathways between affect, alcohol use, and alcohol-involved risk behavior among college students. PMID:22770825

  12. Relationship between alcohol intake, body fat, and physical activity – a population-based study

    PubMed Central

    Liangpunsakul, Suthat; Crabb, David W.; Qi, Rong

    2010-01-01

    Objectives Aside from fat, ethanol is the macronutrient with the highest energy density. Whether the energy derived from ethanol affects the body composition and fat mass is debatable. We investigated the relationship between alcohol intake, body composition, and physical activity in the US population using the third National Health and Nutrition Examination Survey (NHANES III). Methods Ten thousand five hundred and fifty subjects met eligible criteria and constituted our study cohort. Estimated percent body fat and resting metabolic rate were calculated based on the sum of the skinfolds. Multivariate regression analyses were performed accounting for the study sampling weight. Results In both genders, moderate and hazardous alcohol drinkers were younger (p<0.05), had significantly lower BMI (P<0.01) and body weight (p<0.01) than controls, non drinkers. Those with hazardous alcohol consumption had significantly less physical activity compared to those with no alcohol use and moderate drinkers in both genders. Female had significantly higher percent body fat than males. In the multivariate linear regression analyses, the levels of alcohol consumption were found to be an independent predictor associated with lower percent body fat only in male subjects. Conclusions Our results showed that alcoholics are habitually less active and that alcohol drinking is an independent predictor of lower percent body fat especially in male alcoholics. PMID:20696406

  13. Polyvinyl alcohol electrospun nanofibers containing Ag nanoparticles used as sensors for the detection of biogenic amines

    NASA Astrophysics Data System (ADS)

    Marega, Carla; Maculan, Jenny; Rizzi, Gian Andrea; Saini, Roberta; Cavaliere, Emanuele; Gavioli, Luca; Cattelan, Mattia; Giallongo, Giuseppe; Marigo, Antonio; Granozzi, Gaetano

    2015-02-01

    Polyvinyl alcohol (PVA) electrospun nanofibers containing Ag nanoparticles (NPs) have been deposited on glass substrates. The aim of the work was to test the feasibility of this approach for the detection of biogenic amines by using either the Ag localized surface plasmon resonance quenching caused by the adsorption of amines on Ag NPs or by detecting the amines by surface enhanced Raman spectroscopy (SERS) after adsorption, from the gas phase, on the metal NPs. Two different approaches have been adopted. In the first one an ethanol/water solution containing AgNO3 was used directly in the electrospinning apparatus. In this way, a simple heat treatment of the nanofibers mat was sufficient to obtain the formation of Ag NPs inside the nanofibers and a partial cross-link of PVA. In the second procedure, the Ag NPs were deposited on PVA nanofibers by using the supersonic cluster beam deposition method, so that a beam of pure Ag NPs of controlled size was obtained. Exposure of the PVA mat to the beam produced a uniform distribution of the NPs on the nanofibers surface. Ethylendiamine vapors and volatile amines released from fresh shrimp meat were chemisorbed on the nanofibers mats. A SERS spectrum characterized by a diagnostic Ag-N stretching vibration at 230 cm-1 was obtained. The results allow to compare the two different approaches in the detection of ammines.

  14. Exploring knowledge, attitudes, and practices related to alcohol in Mongolia: a national population-based survey

    PubMed Central

    2013-01-01

    Background The leading cause of mortality in Mongolia is Non-Communicable Disease. Alcohol is recognised by the World Health Organization as one of the four major disease drivers and so, in order to better understand and triangulate recent national burden-of-disease surveys and to inform policy responses to alcohol consumption in Mongolia, a national Knowledge, Attitudes and Practices survey was conducted. Focusing on Non-Communicable Diseases and their risk factors, this publication explores the alcohol-related findings of this national survey. Methods A door-to-door, household-based questionnaire was conducted on 3450 people from across Mongolia. Participants were recruited using a multi-stage random cluster sampling technique, and eligibility was granted to permanent residents of households who were aged between 15 and 64 years. A nationally representative sample size was calculated, based on methodologies aligned with the WHO STEPwise approach to Surveillance. Results Approximately 50% of males and 30% of females were found to be current drinkers of alcohol. Moreover, nine in ten respondents agreed that heavy episodic drinking of alcohol is common among Mongolians, and the harms of daily alcohol consumption were generally perceived to be high. Indeed, 90% of respondents regarded daily alcohol consumption as either ‘harmful’ or ‘very harmful’. Interestingly, morning drinking, suggestive of problematic drinking, was highest in rural men and was associated with lower-levels of education and unemployment. Conclusion This research suggests that Mongolia faces an epidemiological challenge in addressing the burden of alcohol use and related problems. Males, rural populations and those aged 25-34 years exhibited the highest levels of risky drinking practices, while urban populations exhibit higher levels of general alcohol consumption. These findings suggest a focus and context for public health measures addressing alcohol-related harm in Mongolia. PMID

  15. Effectiveness of alcohol prevention interventions based on the principles of social marketing: a systematic review

    PubMed Central

    2013-01-01

    Background Alcohol education aims to increase knowledge on the harm related to alcohol, and to change attitudes and drinking behaviour. However, little (lasting) evidence has been found for alcohol education, in changing alcohol-related attitudes and behaviour. Social marketing uses marketing techniques to achieve a social or healthy goal, and can be used in alcohol education. Social marketing consists of eight principles: customer orientation, insight, segmentation, behavioural goals, exchange, competition, methods mix, and is theory based. This review investigates the application of social marketing in alcohol prevention interventions, and whether application of social marketing influences alcohol-related attitudes or behaviour. Method A literature search was conducted in PubMed, PsychInfo, Cochrane and Scopus. Inclusion criteria were that original papers had to describe the effects of an alcohol prevention intervention developed according to one or more principles of social marketing. No limits were set on the age of the participants or on the kind of alcohol prevention intervention. The abstracts of the 274 retrieved studies were reviewed and the full texts of potentially relevant studies were screened. Results Six studies met the inclusion criteria and were included in this review. These six studies showed associations for the application of social marketing techniques on alcohol-related attitudes or behaviour; one study relates to participation in a drinking event, four to alcohol drinking behaviour, two to driving a car while under the influence of alcohol, two to recognition of campaign messages or campaign logo, and one to awareness of the campaign. However, no associations were also found. In addition, the studies had several limitations related to a control group, response rate and study methodology. Conclusion Based on this review, the effect of applying the principles of social marketing in alcohol prevention in changing alcohol-related attitudes or

  16. Vision communications based on LED array and imaging sensor

    NASA Astrophysics Data System (ADS)

    Yoo, Jong-Ho; Jung, Sung-Yoon

    2012-11-01

    In this paper, we propose a brand new communication concept, called as "vision communication" based on LED array and image sensor. This system consists of LED array as a transmitter and digital device which include image sensor such as CCD and CMOS as receiver. In order to transmit data, the proposed communication scheme simultaneously uses the digital image processing and optical wireless communication scheme. Therefore, the cognitive communication scheme is possible with the help of recognition techniques used in vision system. By increasing data rate, our scheme can use LED array consisting of several multi-spectral LEDs. Because arranged each LED can emit multi-spectral optical signal such as visible, infrared and ultraviolet light, the increase of data rate is possible similar to WDM and MIMO skills used in traditional optical and wireless communications. In addition, this multi-spectral capability also makes it possible to avoid the optical noises in communication environment. In our vision communication scheme, the data packet is composed of Sync. data and information data. Sync. data is used to detect the transmitter area and calibrate the distorted image snapshots obtained by image sensor. By making the optical rate of LED array be same with the frame rate (frames per second) of image sensor, we can decode the information data included in each image snapshot based on image processing and optical wireless communication techniques. Through experiment based on practical test bed system, we confirm the feasibility of the proposed vision communications based on LED array and image sensor.

  17. Analytical Sensor Response Function of Viscosity Sensors Based on Layered Piezoelectric Thickness Shear Resonators

    NASA Astrophysics Data System (ADS)

    Benes, Ewald; Nowotny, Helmut; Braun, Stefan; Radel, Stefan; Gröschl, Martin

    Resonant piezoelectric sensors based on bulk acoustic wave (BAW) thickness shear resonators are promising for the inline measurement of fluid viscosity, e.g., in industrial processes. The sensor response function can be derived from the general rigorous transfer matrix description of one-dimensional layered structures consisting of piezoelectric and non-piezoelectric layers of arbitrary number. This model according to Nowotny et al. provides a complete analytical description of the electrical and mechanical behaviour of such structures with two electrodes and arbitrary acoustic termination impedances (Rig-1d-Model). We apply this model to derive the sensor response functions and the mechanical displacement curves of the following configurations appropriate for viscosity sensors: An AT cut quartz crystal plate in contact with vacuum at the backside plane and with the liquid under investigation at the front side plane (QL). An AT cut quartz crystal in contact with the liquid under investigation at both sides (LQL). It is shown that in the QL case the originally only heuristically introduced and well established sensor response function according to Kanasawa can be derived from the Rig-1d-Model by introducing minor approximations. Experimental results are presented for the LQL configuration using an N1000 viscosity reference oil as test fluid.

  18. Robust Model-Based Sensor Fault Monitoring System for Nonlinear Systems in Sensor Networks

    PubMed Central

    Wang, Dejun; Song, Shiyao

    2014-01-01

    A new model-based sensor fault diagnosis (FD) scheme, using an equivalent model, is developed for a kind of Multiple Inputs Multiple Outputs (MIMO) nonlinear system which fulfills the Lipschitz condition. The equivalent model, which is a bank of one-dimensional linear state equations with the bounded model uncertainty, can take the place of a plant's exact nonlinear model in the case of sensor FD. This scheme shows a new perspective whereby, by using the equivalent model, it doesn't have to study the nonlinear internal structure character or get the exact model. The influence of the model uncertainty on the residuals is explained in this paper. A method, called pretreatment, is utilized to minimize the model uncertainty. The eigenstructure assignment method with assistant state is employed to solve the problem of perfect decoupling against the model uncertainty, disturbance, system faults, the relevant actuator faults, or even the case of no input from the relevant actuator. The realization of the proposed scheme is given by an algorithm according to a single sensor FD, and verified by a simulation example. Depending on the above, a sensor fault monitoring system is established by the sensor network and diagnosis logic, then the effectiveness is testified by a simulation. PMID:25320904

  19. Seawater pH sensor based on the long period grating in a single-mode-multimode-single-mode structure

    NASA Astrophysics Data System (ADS)

    Wang, Ke; Klimov, Denis; Kolber, Zbigniew

    2009-03-01

    A pH sensor is developed based on the long-period grating (LPG) inscribed into a single-mode-multimode-single-mode (SMS) structure in order to measure the pH in seawater. The LPG is formed by using a focused CO2 laser at LPG's critical period (1 mm). The transmission characteristics are similar to that of a multimode fiber. However, the SMS structure has a higher sensitivity because mode coupling only happens between the fundamental mode and higher-order modes in the SMS structure. The pH-sensitive hydrogel is made by the thermal cross-link of poly vinyl alcohol and poly acrylic acid. This sensor has been utilized in seawater pH sensing in the range of 6-8. Experiments have confirmed that the sensor is sensitive and repeatable.

  20. Children of Alcoholics: A School-Based Comparative Study.

    ERIC Educational Resources Information Center

    Morey, Connie K.

    1999-01-01

    Examines differences between 4th-6th grade children of alcoholics (COAs) and non-COAs on measures of internalized shame, self-esteem, perceived support, and teacher behavior ratings. No significant differences were found on measures of social support and shame; however self-esteem and teacher ratings for COAs were significantly lower. Gender…

  1. Alcohol Expectancy Multiaxial Assessment: A Memory Network-Based Approach

    ERIC Educational Resources Information Center

    Goldman, Mark S.; Darkes, Jack

    2004-01-01

    Despite several decades of activity, alcohol expectancy research has yet to merge measurement approaches with developing memory theory. This article offers an expectancy assessment approach built on a conceptualization of expectancy as an information processing network. The authors began with multidimensional scaling models of expectancy space,…

  2. Biomarker-Based Approaches for Assessing Alcohol Use Disorders

    PubMed Central

    Niemelä, Onni

    2016-01-01

    Although alcohol use disorders rank among the leading public health problems worldwide, hazardous drinking practices and associated morbidity continue to remain underdiagnosed. It is postulated here that a more systematic use of biomarkers improves the detection of the specific role of alcohol abuse behind poor health. Interventions should be initiated by obtaining information on the actual amounts of recent alcohol consumption through questionnaires and measurements of ethanol and its specific metabolites, such as ethyl glucuronide. Carbohydrate-deficient transferrin is a valuable tool for assessing chronic heavy drinking. Activities of common liver enzymes can be used for screening ethanol-induced liver dysfunction and to provide information on the risk of co-morbidities including insulin resistance, metabolic syndrome and vascular diseases. Conventional biomarkers supplemented with indices of immune activation and fibrogenesis can help to assess the severity and prognosis of ethanol-induced tissue damage. Many ethanol-sensitive biomarkers respond to the status of oxidative stress, and their levels are modulated by factors of life style, including weight gain, physical exercise or coffee consumption in an age- and gender-dependent manner. Therefore, further attention should be paid to defining safe limits of ethanol intake in various demographic categories and establishing common reference intervals for biomarkers of alcohol use disorders. PMID:26828506

  3. Biomarker-Based Approaches for Assessing Alcohol Use Disorders.

    PubMed

    Niemelä, Onni

    2016-02-01

    Although alcohol use disorders rank among the leading public health problems worldwide, hazardous drinking practices and associated morbidity continue to remain underdiagnosed. It is postulated here that a more systematic use of biomarkers improves the detection of the specific role of alcohol abuse behind poor health. Interventions should be initiated by obtaining information on the actual amounts of recent alcohol consumption through questionnaires and measurements of ethanol and its specific metabolites, such as ethyl glucuronide. Carbohydrate-deficient transferrin is a valuable tool for assessing chronic heavy drinking. Activities of common liver enzymes can be used for screening ethanol-induced liver dysfunction and to provide information on the risk of co-morbidities including insulin resistance, metabolic syndrome and vascular diseases. Conventional biomarkers supplemented with indices of immune activation and fibrogenesis can help to assess the severity and prognosis of ethanol-induced tissue damage. Many ethanol-sensitive biomarkers respond to the status of oxidative stress, and their levels are modulated by factors of life style, including weight gain, physical exercise or coffee consumption in an age- and gender-dependent manner. Therefore, further attention should be paid to defining safe limits of ethanol intake in various demographic categories and establishing common reference intervals for biomarkers of alcohol use disorders. PMID:26828506

  4. Triphosgene–Amine Base Promoted Chlorination of Unactivated Aliphatic Alcohols

    PubMed Central

    Villalpando, Andrés; Ayala, Caitlan E.; Watson, Christopher B.; Kartika, Rendy

    2014-01-01

    Unactivated α-branched primary and secondary aliphatic alcohols have been successfully transformed into their corresponding alkyl chlorides in high yields upon treatment with a mixture of triphosgene and pyridine in dichloromethane at reflux. These mild chlorination conditions are high yielding, stereospecific, and well tolerated by numerous sensitive functionalities. Furthermore, no nuisance waste products are generated in the course of the reactions. PMID:23496045

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

    PubMed

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

    2015-06-15

    This paper presents a review of micro- and nano-structure based oligonucleotide detection and quantification techniques. The characteristics of such devices make them very attractive for Point-of-Care or On-Site-Testing biosensing applications. Their small scale means that they can be robust and portable, their compatibility with modern CMOS electronics means that they can easily be incorporated into hand-held devices and their suitability for mass production means that, out of the different approaches to oligonucleotide detection, they are the most suitable for commercialisation. This review discusses the advantages of micro- and nano-structure based sensors and covers the various oligonucleotide detection techniques that have been developed to date. These include: Bulk Acoustic Wave and Surface Acoustic Wave devices, micro- and nano-cantilever sensors, gene Field Effect Transistors, and nanowire and nanopore based sensors. Oligonucleotide immobilisation techniques are also discussed. PMID:25655465

  6. Aptamer based electrochemical sensors for emerging environmental pollutants

    PubMed Central

    Hayat, Akhtar; Marty, Jean L.

    2014-01-01

    Environmental contaminants monitoring is one of the key issues in understanding and managing hazards to human health and ecosystems. In this context, aptamer based electrochemical sensors have achieved intense significance because of their capability to resolve a potentially large number of problems and challenges in environmental contamination. An aptasensor is a compact analytical device incorporating an aptamer (oligonulceotide) as the sensing element either integrated within or intimately associated with a physiochemical transducer surface. Nucleic acid is well known for the function of carrying and passing genetic information, however, it has found a key role in analytical monitoring during recent years. Aptamer based sensors represent a novelty in environmental analytical science and there are great expectations for their promising performance as alternative to conventional analytical tools. This review paper focuses on the recent advances in the development of aptamer based electrochemical sensors for environmental applications with special emphasis on emerging pollutants. PMID:25019067

  7. Aptamer based electrochemical sensors for emerging environmental pollutants

    NASA Astrophysics Data System (ADS)

    Hayat, Akhtar; Marty, Jean Louis

    2014-06-01

    Environmental contaminants monitoring is one of the key issues in understanding and managing hazards to human health and ecosystems. In this context, aptamer based electrochemical sensors have achieved intense significance because of their capability to resolve a potentially large number of problems and challenges in environmental contamination. An aptasensor is a compact analytical device incorporating an aptamer (oligonulceotide) as the sensing element either integrated within or intimately associated with a physiochemical transducer surface. Nucleic acid is well known for the function of carrying and passing genetic information, however, it has found a key role in analytical monitoring during recent years. Aptamer based sensors represent a novelty in environmental analytical science and there are great expectations for their promising performance as alternative to conventional analytical tools. This review paper focuses on the recent advances in the development of aptamer based electrochemical sensors for environmental applications with special emphasis on emerging pollutants.

  8. Carbon nanotube based pressure sensor for flexible electronics

    SciTech Connect

    So, Hye-Mi; Sim, Jin Woo; Kwon, Jinhyeong; Yun, Jongju; Baik, Seunghyun; Chang, Won Seok

    2013-12-15

    Highlights: • The electromechanical change of vertically aligned carbon nanotubes. • Fabrication of CNT field-effect transistor on flexible substrate. • CNT based FET integrated active pressure sensor. • The integrated device yields an increase in the source-drain current under pressure. - Abstract: A pressure sensor was developed based on an arrangement of vertically aligned carbon nanotubes (VACNTs) supported by a polydimethylsiloxane (PDMS) matrix. The VACNTs embedded in the PDMS matrix were structurally flexible and provided repeated sensing operation due to the high elasticities of both the polymer and the carbon nanotubes (CNTs). The conductance increased in the presence of a loading pressure, which compressed the material and induced contact between neighboring CNTs, thereby producing a dense current path and better CNT/metal contacts. To achieve flexible functional electronics, VACNTs based pressure sensor was integrated with field-effect transistor, which is fabricated using sprayed semiconducting carbon nanotubes on plastic substrate.

  9. Facts about Alcohol and Alcoholism.

    ERIC Educational Resources Information Center

    Hall, Leonard C.

    Recognition of alcoholism as a treatable illness is a result of public education based on scientific facts. This publication, a digest of a more detailed survey of research about drinking and alcoholism, presents information about alcohol and its effects on individuals and society. It provides facts about the short-term and long-term effects of…

  10. A Bionic Camera-Based Polarization Navigation Sensor

    PubMed Central

    Wang, Daobin; Liang, Huawei; Zhu, Hui; Zhang, Shuai

    2014-01-01

    Navigation and positioning technology is closely related to our routine life activities, from travel to aerospace. Recently it has been found that Cataglyphis (a kind of desert ant) is able to detect the polarization direction of skylight and navigate according to this information. This paper presents a real-time bionic camera-based polarization navigation sensor. This sensor has two work modes: one is a single-point measurement mode and the other is a multi-point measurement mode. An indoor calibration experiment of the sensor has been done under a beam of standard polarized light. The experiment results show that after noise reduction the accuracy of the sensor can reach up to 0.3256°. It is also compared with GPS and INS (Inertial Navigation System) in the single-point measurement mode through an outdoor experiment. Through time compensation and location compensation, the sensor can be a useful alternative to GPS and INS. In addition, the sensor also can measure the polarization distribution pattern when it works in multi-point measurement mode. PMID:25051029

  11. A bionic camera-based polarization navigation sensor.

    PubMed

    Wang, Daobin; Liang, Huawei; Zhu, Hui; Zhang, Shuai

    2014-01-01

    Navigation and positioning technology is closely related to our routine life activities, from travel to aerospace. Recently it has been found that Cataglyphis (a kind of desert ant) is able to detect the polarization direction of skylight and navigate according to this information. This paper presents a real-time bionic camera-based polarization navigation sensor. This sensor has two work modes: one is a single-point measurement mode and the other is a multi-point measurement mode. An indoor calibration experiment of the sensor has been done under a beam of standard polarized light. The experiment results show that after noise reduction the accuracy of the sensor can reach up to 0.3256°. It is also compared with GPS and INS (Inertial Navigation System) in the single-point measurement mode through an outdoor experiment. Through time compensation and location compensation, the sensor can be a useful alternative to GPS and INS. In addition, the sensor also can measure the polarization distribution pattern when it works in multi-point measurement mode. PMID:25051029

  12. Illicit material detector based on gas sensors and neural networks

    NASA Astrophysics Data System (ADS)

    Grimaldi, Vincent; Politano, Jean-Luc

    1997-02-01

    In accordance with its missions, le Centre de Recherches et d'Etudes de la Logistique de la Police Nationale francaise (CREL) has been conducting research for the past few years targeted at detecting drugs and explosives. We have focused our approach of the underlying physical and chemical detection principles on solid state gas sensors, in the hope of developing a hand-held drugs and explosives detector. The CREL and Laboratory and Scientific Services Directorate are research partners for this project. Using generic hydrocarbon, industrially available, metal oxide sensors as illicit material detectors, requires usage precautions. Indeed, neither the product's concentrations, nor even the products themselves, belong to the intended usage specifications. Therefore, the CREL is currently investigating two major research topics: controlling the sensor's environment: with environmental control we improve the detection of small product concentration; determining detection thresholds: both drugs and explosives disseminate low gas concentration. We are attempting to quantify the minimal concentration which triggers detection. In the long run, we foresee a computer-based tool likely to detect a target gas in a noisy atmosphere. A neural network is the suitable tool for interpreting the response of heterogeneous sensor matrix. This information processing structure, alongside with proper sensor environment control, will lessen the repercussions of common MOS sensor sensitivity characteristic dispersion.

  13. MEMS Based Flow Sensors and Their Application on Flow Imaging

    NASA Astrophysics Data System (ADS)

    Yang, Yingchen; Chen, Nannan; Engel, Jonathan; Tucker, Craig; Pandya, Saunvit; Liu, Chang

    2006-11-01

    We report characterization and application of recently developed, MEMS based, out-of-plane hot-wire anemometer (HWA) sensor and bio-inspired artificial hair cell (AHC) sensor. Sensitivities of 0.2mm/s for HWA and 0.1mm/s for AHC have been achieved in water flows, comparing with 1mm/s of a conventional HWA. In contrast to its high sensitivity, the AHC sensor can survive 55 bending of its hair, making it very robust. After calibration, both HWA and AHC sensors were employed for dipole field and wake measurements. The dipole field was generated by a vibrating sphere in a large water tank; the measurement results match very well with the analytical model. The wake was created by a circular cylinder in a water channel; the RMS velocity distributions replicate the main features of a typical wake accurately. The two types of sensors were also applied in array format to mimic a fish lateral line for imaging hydrodynamic events. Multi-modal sensors capable of simultaneous measurement of flow velocity, shear stress, pressure and temperature are under development.

  14. Resonant Magnetic Field Sensors Based On MEMS Technology.

    PubMed

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

    2009-01-01

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

  15. Resonant Magnetic Field Sensors Based On MEMS Technology

    PubMed Central

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

    2009-01-01

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

  16. Generic model for smart-sensor-based data acquisition system

    NASA Astrophysics Data System (ADS)

    Ehrlich, Jacques; Zerrouki, Amal; Galisson, Arnaud; Demassieux, Nicolas

    1996-05-01

    Smart sensor is a recent concept presenting numerous advantages such as versatility, strong electromagnetic immunity, reduction of the connectivity, high computation power, etc. In civil engineering smart sensor based systems are well suited due to the large amount of spatially distant transducers and the need of large computational power. However, such systems require long development time, especially in their software part, and beside the multitude of instrumentation problems encountered, the need of a generic model is strong. The aim of the model is the design of a software generator for distributed data acquisition system. The key of our system is in the description of an instrumentation plane under the form of a data dependence graph (DDG). The goal of the generator is to map and 'execute' that DDG on the physical architecture according to the number of transducers, their affectation to the smart sensors and a PC based system controller. In this paper, after an outline of the smart sensor concept, we describe the DDG based representation of the instrumentation plan. An example of bridge monitoring is then described. Finally, the smart sensor, the system controller and the network modelization are outlined and their ability to allow the DDG mapping with the help of local or remote variable is shown.

  17. Electrochemical DNA Hybridization Sensors Based on Conducting Polymers

    PubMed Central

    Rahman, Md. Mahbubur; Li, Xiao-Bo; Lopa, Nasrin Siraj; Ahn, Sang Jung; Lee, Jae-Joon

    2015-01-01

    Conducting polymers (CPs) are a group of polymeric materials that have attracted considerable attention because of their unique electronic, chemical, and biochemical properties. This is reflected in their use in a wide range of potential applications, including light-emitting diodes, anti-static coating, electrochromic materials, solar cells, chemical sensors, biosensors, and drug-release systems. Electrochemical DNA sensors based on CPs can be used in numerous areas related to human health. This review summarizes the recent progress made in the development and use of CP-based electrochemical DNA hybridization sensors. We discuss the distinct properties of CPs with respect to their use in the immobilization of probe DNA on electrode surfaces, and we describe the immobilization techniques used for developing DNA hybridization sensors together with the various transduction methods employed. In the concluding part of this review, we present some of the challenges faced in the use of CP-based DNA hybridization sensors, as well as a future perspective. PMID:25664436

  18. Adaptive inferential sensors based on evolving fuzzy models.

    PubMed

    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

  19. SiC-Based Schottky Diode Gas Sensors

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W.; Neudeck, Philip G.; Chen, Liang-Yu; Knight, Dak; Liu, Chung-Chiun; Wu, Quing-Hai

    1997-01-01

    Silicon carbide based Schottky diode gas sensors are being developed for high temperature applications such as emission measurements. Two different types of gas sensitive diodes will be discussed in this paper. By varying the structure of the diode, one can affect the diode stability as well as the diode sensitivity to various gases. It is concluded that the ability of SiC to operate as a high temperature semiconductor significantly enhances the versatility of the Schottky diode gas sensing structure and will potentially allow the fabrication of a SiC-based gas sensor arrays for versatile high temperature gas sensing applications.

  20. Effect of hand-based sensors on manipulator control performance

    NASA Technical Reports Server (NTRS)

    Bejczy, A. K.

    1977-01-01

    Manipulator task categories and motion phases require various hand-based information systems to meet the control performance requirements. The effect of proximity, tactile and force/torque sensors on the performance of remote manipulator control is discussed. An overview is presented on various experimental hand-based information systems which provide the manipulator controller some non-visual 'awareness' of the task environment. The rest of the paper describes and evaluates various control experiments performed at JPL using hand-mounted proximity sensors to guide and control hand motion near solid objects.

  1. The Genetics of Alcohol Dependence: Advancing Towards Systems-based Approaches

    PubMed Central

    Palmer, RHC; McGeary, JE; Francazio, S; Raphael, BJ; Lander, AD; Heath, AC; Knopik, VS

    2012-01-01

    BACKGROUND Personalized treatment for psychopathologies, in particular alcoholism, is highly dependent upon our ability to identify patterns of genetic and environmental effects that influence a person’s risk. Unfortunately, array-based whole genome investigations into heritable factors that explain why one person becomes dependent upon alcohol and another does not, have indicated that alcohol’s genetic architecture is highly complex. That said, uncovering and interpreting the missing heritability in alcohol genetics research has become all the more important, especially since the problem may extend to our inability to model the cumulative and combinatorial relationships between common and rare genetic variants. As numerous studies begin to illustrate the dependency of alcohol pharmacotherapies on an individual’s genotype, the field is further challenged to identify new ways to transcend agnostic genomewide association approaches. We discuss insights from genetic studies of alcohol related diseases, as well as issues surrounding alcohol’s genetic complexity and etiological heterogeneity. Finally, we describe the need for innovative systems-based approaches (Systems Genetics) that can provide additional statistical power that can enhance future gene-finding strategies and help to identify heretofore-unrealized mechanisms that may provide new targets for prevention/treatments efforts. Emerging evidence from early studies suggest that Systems Genetics has the potential to organize our neurological, pharmacological, and genetic understanding of alcohol dependence into a biologically plausible framework that represents how perturbations across evolutionarily robust biological systems determine susceptibility to alcohol dependence. PMID:22854292

  2. Biosensors based on porous cellulose nanocrystal-poly(vinyl alcohol) scaffolds.

    PubMed

    Schyrr, Bastien; Pasche, Stéphanie; Voirin, Guy; Weder, Christoph; Simon, Yoan C; Foster, E Johan

    2014-08-13

    Cellulose nanocrystals (CNCs), which offer a high aspect ratio, large specific surface area, and large number of reactive surface groups, are well suited for the facile immobilization of high density biological probes. We here report functional high surface area scaffolds based on cellulose nanocrystals (CNCs) and poly(vinyl alcohol) (PVA) and demonstrate that this platform is useful for fluorescence-based sensing schemes. Porous CNC/PVA nanocomposite films with a thickness of 25-70 nm were deposited on glass substrates by dip-coating with an aqueous mixture of the CNCs and PVA, and the porous nanostructure was fixated by heat treatment. In a subsequent step, a portion of the scaffold's hydroxyl surface groups was reacted with 2-(acryloxy)ethyl (3-isocyanato-4-methylphenyl)carbamate to permit the immobilization of thiolated fluorescein-substituted lysine, which was used as a first sensing motif, via nucleophile-based thiol-ene Michael addition. The resulting sensor films exhibit a nearly instantaneous and pronounced change of their fluorescence emission intensity in response to changes in pH. The approach was further extended to the detection of protease activity by immobilizing a Förster-type resonance energy transfer chromophore pair via a labile peptide sequence to the scaffold. This sensing scheme is based on the degradation of the protein linker in the presence of appropriate enzymes, which separate the chromophores and causes a turn-on of the originally quenched fluorescence. Using a standard benchtop spectrometer to monitor the increase in fluorescence intensity, trypsin was detected at a concentration of 250 μg/mL, i.e., in a concentration that is typical for abnormal proteolytic activity in wound fluids. PMID:24955644

  3. Validation of Underwater Sensor Package Using Feature Based SLAM

    PubMed Central

    Cain, Christopher; Leonessa, Alexander

    2016-01-01

    Robotic vehicles working in new, unexplored environments must be able to locate themselves in the environment while constructing a picture of the objects in the environment that could act as obstacles that would prevent the vehicles from completing their desired tasks. In enclosed environments, underwater range sensors based off of acoustics suffer performance issues due to reflections. Additionally, their relatively high cost make them less than ideal for usage on low cost vehicles designed to be used underwater. In this paper we propose a sensor package composed of a downward facing camera, which is used to perform feature tracking based visual odometry, and a custom vision-based two dimensional rangefinder that can be used on low cost underwater unmanned vehicles. In order to examine the performance of this sensor package in a SLAM framework, experimental tests are performed using an unmanned ground vehicle and two feature based SLAM algorithms, the extended Kalman filter based approach and the Rao-Blackwellized, particle filter based approach, to validate the sensor package. PMID:26999142

  4. Validation of Underwater Sensor Package Using Feature Based SLAM.

    PubMed

    Cain, Christopher; Leonessa, Alexander

    2016-01-01

    Robotic vehicles working in new, unexplored environments must be able to locate themselves in the environment while constructing a picture of the objects in the environment that could act as obstacles that would prevent the vehicles from completing their desired tasks. In enclosed environments, underwater range sensors based off of acoustics suffer performance issues due to reflections. Additionally, their relatively high cost make them less than ideal for usage on low cost vehicles designed to be used underwater. In this paper we propose a sensor package composed of a downward facing camera, which is used to perform feature tracking based visual odometry, and a custom vision-based two dimensional rangefinder that can be used on low cost underwater unmanned vehicles. In order to examine the performance of this sensor package in a SLAM framework, experimental tests are performed using an unmanned ground vehicle and two feature based SLAM algorithms, the extended Kalman filter based approach and the Rao-Blackwellized, particle filter based approach, to validate the sensor package. PMID:26999142

  5. Neural network sensor fusion: Creation of a virtual sensor for cloud-base height estimation

    NASA Astrophysics Data System (ADS)

    Pasika, Hugh Joseph Christopher

    2000-10-01

    Sensor fusion has become a significant area of signal processing research that draws on a variety of tools. Its goals are many, however in this thesis, the creation of a virtual sensor is paramount. In particular, neural networks are used to simulate the output of a LIDAR (LASER. RADAR) that measures cloud-base height. Eye-safe LIDAR is more accurate than the standard tool that would be used for such measurement; the ceilometer. The desire is to make cloud-base height information available at a network of ground-based meteorological stations without actually installing LIDAR sensors. To accomplish this, fifty-seven sensors ranging from multispectral satellite information to standard atmospheric measurements such as temperature and humidity, are fused in what can only be termed as a very complex, nonlinear environment. The result is an accurate prediction of cloud-base height. Thus, a virtual sensor is created. A total of four different learning algorithms were studied; two global and two local. In each case, the very best state-of-the-art learning algorithms have been selected. Local methods investigated are the regularized radial basis function network, and the support vector machine. Global methods include the standard backpropagation with momentum trained multilayer perceptron (used as a benchmark) and the multilayer perceptron trained via the Kalman filter algorithm. While accuracy is the primary concern, computational considerations potentially limit the application of several of the above techniques. Thus, in all cases care was taken to minimize computational cost. For example in the case of the support vector machine, a method of partitioning the problem in order to reduce memory requirements and make the optimization over a large data set feasible was employed and in the Kalman algorithm case, node-decoupling was used to dramatically reduce the number of operations required. Overall, the methods produced somewhat equivalent mean squared errors indicating

  6. Family-based study of brain-derived neurotrophic factor (BDNF) gene polymorphism in alcohol dependence.

    PubMed

    Grzywacz, Anna; Samochowiec, Agnieszka; Ciechanowicz, Andrzej; Samochowiec, Jerzy

    2010-01-01

    Brain-derived neurotrophic factor (BDNF) belongs to a family of proteins related to the nerve growth factor family, which are responsible for the proliferation, survival and differentiation of neurons. BDNF is thought to be involved in the pathogenesis of bipolar disorder, schizophrenia, eating disorders and addiction. We hypothesize that a functionally relevant polymorphism of the BDNF gene promoter may be associated with the pathogenesis of alcohol dependence. We performed an association study of 141 families with alcohol dependence. One hundred and thirty-eight healthy control subjects were matched based on ethnicity and gender. An association between the BDNF Val66Met gene polymorphism and alcoholism was not found. PMID:21098877

  7. Polar format statistical image processing based fiber optic pressure sensors

    NASA Astrophysics Data System (ADS)

    Alver, Muhammed B.; Toker, Onur; Fidanboylu, Kemal

    2014-09-01

    This paper presents detailed study on the development of a fiber optic sensor system to design a pressure sensor with different sensor configurations. The sensor used in the experiments is based on modal power distribution (MPD) technique. MPD technique is spatial modulation of the modal power in multimode fibers. Stress measurements and CCD camera based techniques were investigated in this research. Differently from earlier MPD works, all of the data gathered from CCD camera are used instead of using some part of the data, the ring shaped pictures taken from the CCD camera converted to polar coordinates, and so stripe shaped pictures are obtained. Four different features are calculated from these converted pictures. R component of the center of mass in the polar form is the first feature. It is calculated because it was expected to decrease monotonically with respect to increasing applied pressure. Second and third features are ring thickness in polar form with taking brightness of each pixel into account and ring thickness in polar form without taking brightness of each pixel into account. These features are calculated to analyze the effect of each pixel's brightness. It was expected for these two features that there will not be a big margin between them. Fourth feature is the ratio between third feature and first feature. A MATLAB code is written to correlate these features and applied force to the sensor. Various experiments conducted to analyze this correlation. Pictures are taken from CCD camera with 1 kg steps and from the written MATLAB code, graphics of each feature versus the applied force are generated. Experimental results showed that, the sensitivity of the proposed sensor is much higher than sensors that uses only some part of the collected data in earlier MPD studies. Furthermore, results are almost exactly the same that what was expected for the four proposed features. Results also showed that converting pictures to the polar form increases the

  8. Enhanced Sensitivity of Gas Sensor Based on Poly(3-hexylthiophene) Thin-Film Transistors for Disease Diagnosis and Environment Monitoring

    PubMed Central

    Cavallari, Marco R.; Izquierdo, José E. E.; Braga, Guilherme S.; Dirani, Ely A. T.; Pereira-da-Silva, Marcelo A.; Rodríguez, Estrella F. G.; Fonseca, Fernando J.

    2015-01-01

    Electronic devices based on organic thin-film transistors (OTFT) have the potential to supply the demand for portable and low-cost gadgets, mainly as sensors for in situ disease diagnosis and environment monitoring. For that reason, poly(3-hexylthiophene) (P3HT) as the active layer in the widely-used bottom-gate/bottom-contact OTFT structure was deposited over highly-doped silicon substrates covered with thermally-grown oxide to detect vapor-phase compounds. A ten-fold organochloride and ammonia sensitivity compared to bare sensors corroborated the application of this semiconducting polymer in sensors. Furthermore, P3HT TFTs presented approximately three-order higher normalized sensitivity than any chemical sensor addressed herein. The results demonstrate that while TFTs respond linearly at the lowest concentration values herein, chemical sensors present such an operating regime mostly above 2000 ppm. Simultaneous alteration of charge carrier mobility and threshold voltage is responsible for pushing the detection limit down to units of ppm of ammonia, as well as tens of ppm of alcohol or ketones. Nevertheless, P3HT transistors and chemical sensors could compose an electronic nose operated at room temperature for a wide range concentration evaluation (1–10,000 ppm) of gaseous analytes. Targeted analytes include not only biomarkers for diseases, such as uremia, cirrhosis, lung cancer and diabetes, but also gases for environment monitoring in food, cosmetic and microelectronics industries. PMID:25912354

  9. Voltage-Biased Magnetic Sensors Based on Tuned Varistors

    NASA Astrophysics Data System (ADS)

    Pandey, R. K.; Stapleton, William. A.; Sutanto, Ivan; Shamsuzzoha, M.

    2015-04-01

    In this paper, we explore the possibility of finding practical applications when the nonlinear current-voltage ( I- V) characteristics of a varistor are modified by the application of external magnetic fields. With this goal in mind, varistors based on a pseudobrookite oxide semiconductor have been studied. Pseudobrookite (PsB) is a wide bandgap n-type semiconductor with the bandgap of 2.77 eV. It is also weakly ferromagnetic. The "voltage-dependent resistor" (VDR) mode of the magnetically-tuned pseudobrookite varistors offers an opportunity to advance magnetic sensor technology. The resistive and magnetoresistive parameters of PsB VDRs exhibit good responses to applied magnetic fields and they can therefore be the basis for the fabrication of simple yet practical magnetic sensors. These sensors can cover the range of magnetic fields between 0 and 4500 Oe with good accuracy, and could possibly be considered as a substitute for Hall Effect-based sensors for many applications. Also, due to their simple structure, they would be rugged and not susceptible to abuses. They may also be suitable for applications in hazardous environments such as high temperatures and atmospheres having the presence of radiation, such as neutrons, protons, etc. It is also possible that these novel sensors could be suitable for geological applications such as in well logging in search of energy sources.

  10. A Universal Intelligent System-on-Chip Based Sensor Interface

    PubMed Central

    Mattoli, Virgilio; Mondini, Alessio; Mazzolai, Barbara; Ferri, Gabriele; Dario, Paolo

    2010-01-01

    The need for real-time/reliable/low-maintenance distributed monitoring systems, e.g., wireless sensor networks, has been becoming more and more evident in many applications in the environmental, agro-alimentary, medical, and industrial fields. The growing interest in technologies related to sensors is an important indicator of these new needs. The design and the realization of complex and/or distributed monitoring systems is often difficult due to the multitude of different electronic interfaces presented by the sensors available on the market. To address these issues the authors propose the concept of a Universal Intelligent Sensor Interface (UISI), a new low-cost system based on a single commercial chip able to convert a generic transducer into an intelligent sensor with multiple standardized interfaces. The device presented offers a flexible analog and/or digital front-end, able to interface different transducer typologies (such as conditioned, unconditioned, resistive, current output, capacitive and digital transducers). The device also provides enhanced processing and storage capabilities, as well as a configurable multi-standard output interface (including plug-and-play interface based on IEEE 1451.3). In this work the general concept of UISI and the design of reconfigurable hardware are presented, together with experimental test results validating the proposed device. PMID:22163624

  11. Nanotechnology-Based Electrochemical Sensors for Biomonitoring Chemical Exposures

    PubMed Central

    Barry, Richard C.; Lin, Yuehe; Wang, Jun; Liu, Guodong; Timchalk, Charles A.

    2009-01-01

    The coupling of dosimetry measurements and modeling represents a promising strategy for deciphering the relationship between chemical exposure and disease outcome. To support the development and implementation of biological monitoring programs, quantitative technologies for measuring xenobiotic exposure are needed. The development of portable nanotechnology-based electrochemical sensors has the potential to meet the needs for low cost, rapid, high-throughput and ultrasensitive detectors for biomonitoring an array of chemical markers. Highly selective electrochemical (EC) sensors capable of pM sensitivity, high-throughput and low sample requirements (<50uL) are discussed. These portable analytical systems have many advantages over currently available technologies, thus potentially representing the next-generation of biomonitoring analyzers. This manuscript highlights research focused on the development of field-deployable analytical instruments based on EC detection. Background information and a general overview of EC detection methods and integrated use of nanomaterials in the development of these sensors are provided. New developments in EC sensors using various types of screen-printed electrodes, integrated nanomaterials, and immunoassays are presented. Recent applications of EC sensors for assessing exposure to pesticides or detecting biomarkers of disease are highlighted to demonstrate the ability to monitor chemical metabolites, enzyme activity, or protein biomarkers of disease. In addition, future considerations and opportunities for advancing the use of EC platforms for dosimetric studies are discussed. PMID:19018275

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

    NASA Technical Reports Server (NTRS)

    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.

  13. San Mateo County's Server Information Program (S.I.P.): A Community-Based Alcohol Server Training Program.

    ERIC Educational Resources Information Center

    de Miranda, John

    The field of alcohol server awareness and training has grown dramatically in the past several years and the idea of training servers to reduce alcohol problems has become a central fixture in the current alcohol policy debate. The San Mateo County, California Server Information Program (SIP) is a community-based prevention strategy designed to…

  14. Effect of Dexamethasone-Loaded Poly(Lactic-Co-Glycolic Acid) Microsphere/Poly(Vinyl Alcohol) Hydrogel Composite Coatings on the Basic Characteristics of Implantable Glucose Sensors

    PubMed Central

    Wang, Yan; Vaddiraju, Santhisagar; Qiang, Liangliang; Xu, Xiaoming; Papadimitrakopoulos, Fotios; Burgess, Diane J.

    2012-01-01

    Background Hydrogels alone and in combination with microsphere drug delivery systems are being considered as biocompatible coatings for implantable glucose biosensors to prevent/minimize the foreign body response. Previously, our group has demonstrated that continuous release of dexamethasone from poly(lactic-co-glycolic acid) (PLGA) microsphere/poly(vinyl alcohol) (PVA) hydrogel composites can successfully prevent foreign body response at the implantation site. The objective of this study was to investigate the effect of this composite coating on sensor functionality. Methods The PLGA microsphere/PVA hydrogel coatings were prepared and applied to glucose biosensors. The swelling properties of the composite coatings and their diffusivity to glucose were evaluated as a function of microsphere loading. Sensor linearity, response time, and sensitivity were also evaluated as a function of coating composition. Results The PLGA microsphere/PVA hydrogel composite coating did not compromise sensor linearity (sensors were linear up to 30 mM), which is well beyond the physiological glucose range (2 to 22 mM). The sensor response time did increase in the presence of the coating (from 10 to 19 s); however, this response time was still less than the average reported values. Although the sensitivity of the sensors decreased from 73 to 62 nA/mM glucose when the PLGA microsphere loading in the PVA hydrogel changed from 0 to 100 mg/ml, this reduced sensitivity is acceptable for sensor functionality. The changes in sensor response time and sensitivity were due to changes in glucose permeability as a result of the coatings. The embedded PLGA microspheres reduced the fraction of bulk water present in the hydrogel matrix and consequently reduced glucose diffusion. Conclusions This study demonstrates that the PLGA microsphere/PVA hydrogel composite coatings allow sufficient glucose diffusion and sensor functionality and therefore may be utilized as a smart coating for implantable

  15. Estimation of Alcohol Concentration of Red Wine Based on Cole-Cole Plot

    NASA Astrophysics Data System (ADS)

    Watanabe, Kota; Taka, Yoshinori; Fujiwara, Osamu

    To evaluate the quality of wine, we previously measured the complex relative permittivity of wine in the frequency range from 10 MHz to 6 GHz with a network analyzer, and suggested a possibility that the maturity and alcohol concentration of wine can simultaneously be estimated from the Cole-Cole plot. Although the absolute accuracy has not been examined yet, this method will enable one to estimate the alcohol concentration of alcoholic beverages without any distillation equipment simply. In this study, to investigate the estimation accuracy of the alcohol concentration of wine by its Cole-Cole plots, we measured the complex relative permittivity of pure water and diluted ethanol solution from 100 MHz to 40 GHz, and obtained the dependence of the Cole-Cole plot parameters on alcohol concentration and temperature. By using these results as calibration data, we estimated the alcohol concentration of red wine from the Cole-Cole plots, which was compared with the measured one based on a distillation method. As a result, we have confirmed that the estimated alcohol concentration of red wine agrees with the measured results in an absolute error by less than 1 %.

  16. Preparation and properties of low boiling point of alcohol and acetone-based magnetic fluid

    NASA Astrophysics Data System (ADS)

    Fujita, T.; Miyazaki, T.; Nishiyama, H.; Jeyadevan, B.

    1999-07-01

    Ultra-fine magnetic particles are difficult to be dispersed in low boiling point solvents such as alcohol (C 1-C 4) and acetone. In this paper, we report the preparation methods of several alcohol and acetone-based magnetic fluids. The stability of magnetic fluid depended on the HLB (hydrophile-lipophile balance) of the solvent and alkyl chain lengths of organic layers. The fluid was most stable only when the HLB value of surfactant and the solvents are similar.

  17. [The resolution of racemic sec-phenethyl alcohol on cellulose tribenzoate-based CSP: influence of different alcohols in the mobile phase].

    PubMed

    Wang, L; Lü, S; Gao, P; Li, S

    1999-07-01

    Several primary and secondary alcohols (ethanol, 1-propanol, 2-propanol, 1-butanol) were used as the mobile phase components separately, to investigate their effects on the capacity factor and stereoselectivity of sec-phenethyl alcohol enantiomers on cellulose tribenzoate-based CSP. The chiral recognition mechanism for the enantiomeric aromatic alcohols studied may involve: (1) the aromatic portion of the solute may insert into a chiral cavity of the CSP through a hydrogen bonding interaction between the solute's alcoholic hydrogen and the ester carbonyl group on the CSP; (2) the mobile phase modifiers (various alcohols) compete with the solutes for chiral, as well as achiral, binding sites on the CSP; (3) the structure of the modifier has some effect on stereoselectivity through an alteration of the steric environment of the chiral cavity. PMID:12552849

  18. Mitigating ground-based sensor failures with video motion detection

    NASA Astrophysics Data System (ADS)

    Macior, Robert E.; Knauth, Jonathan P.; Walter, Sharon M.; Evans, Richard

    2008-10-01

    Unattended Ground Sensor (UGS) systems typically employ distributed sensor nodes utilizing seismic, magnetic or passive IR sensing modalities to alarm if activity is present. The use of an imaging component to verify sensor events is beneficial to create actionable intelligence. Integration of the ground-based images with other ISR data requires that the images contain valid activity and are appropriately formatted, such as prescribed by Standard NATO Agreement (STANAG) 4545 or the National Imagery Transmission Format, version 2.1 (NITF 2.1). Ground activity sensors suffer from false alarms due to meteorological or biological activity. The addition of imaging allows the analyst to differentiate valid threats from nuisance alarms. Images are prescreened based on target size and temperature difference relative to the background. The combination of video motion detection based on thermal imaging with seismic, magnetic or passive IR sensing modalities improves data quality through multi-phenomenon combinatorial logic. The ground-based images having a nominally vertical aspect are transformed to the horizontal geospatial domain for exploitation and correlation of UGS imagery with other ISR data and for efficient archive and retrieval purposes. The description of an UGS system utilized and solutions that were developed and implemented during an experiment to correlate and fuse IR still imagery with ground moving target information, forming real-time, actionable, coalition intelligence, are presented.

  19. Connected Dominating Set Based Topology Control in Wireless Sensor Networks

    ERIC Educational Resources Information Center

    He, Jing

    2012-01-01

    Wireless Sensor Networks (WSNs) are now widely used for monitoring and controlling of systems where human intervention is not desirable or possible. Connected Dominating Sets (CDSs) based topology control in WSNs is one kind of hierarchical method to ensure sufficient coverage while reducing redundant connections in a relatively crowded network.…

  20. Recent Electrochemical and Optical Sensors in Flow-Based Analysis

    PubMed Central

    Chailapakul, Orawon; Ngamukot, Passapol; Yoosamran, Alongkorn; Siangproh, Weena; Wangfuengkanagul, Nattakarn

    2006-01-01

    Some recent analytical sensors based on electrochemical and optical detection coupled with different flow techniques have been chosen in this overview. A brief description of fundamental concepts and applications of each flow technique, such as flow injection analysis (FIA), sequential injection analysis (SIA), all injection analysis (AIA), batch injection analysis (BIA), multicommutated FIA (MCFIA), multisyringe FIA (MSFIA), and multipumped FIA (MPFIA) were reviewed.

  1. Real-Time, Sensor-Based Computing in the Laboratory.

    ERIC Educational Resources Information Center

    Badmus, O. O.; And Others

    1996-01-01

    Demonstrates the importance of Real-Time, Sensor-Based (RTSB) computing and how it can be easily and effectively integrated into university student laboratories. Describes the experimental processes, the process instrumentation and process-computer interface, the computer and communications systems, and typical software. Provides much technical…

  2. Engineering Paper-Based Sensors for Zika Virus

    DOE PAGESBeta

    Meagher, Robert J.; Negrete, Oscar A.; Van Rompay, Koen K.

    2016-05-01

    The emergence of Zika virus in Latin America has created an urgent need for new, simple yet sensitive diagnostic tests. We highlight recent work using paper-based sensors coupled with CRISPR/Cas9 to detect Zika RNA, as a new approach to rapid development and deployment of field-ready diagnostics for emerging infectious diseases.

  3. Image-Based Environmental Monitoring Sensor Application Using an Embedded Wireless Sensor Network

    PubMed Central

    Paek, Jeongyeup; Hicks, John; Coe, Sharon; Govindan, Ramesh

    2014-01-01

    This article discusses the experiences from the development and deployment of two image-based environmental monitoring sensor applications using an embedded wireless sensor network. Our system uses low-power image sensors and the Tenet general purpose sensing system for tiered embedded wireless sensor networks. It leverages Tenet's built-in support for reliable delivery of high rate sensing data, scalability and its flexible scripting language, which enables mote-side image compression and the ease of deployment. Our first deployment of a pitfall trap monitoring application at the James San Jacinto Mountain Reserve provided us with insights and lessons learned into the deployment of and compression schemes for these embedded wireless imaging systems. Our three month-long deployment of a bird nest monitoring application resulted in over 100,000 images collected from a 19-camera node network deployed over an area of 0.05 square miles, despite highly variable environmental conditions. Our biologists found the on-line, near-real-time access to images to be useful for obtaining data on answering their biological questions. PMID:25171121

  4. Image-based environmental monitoring sensor application using an embedded wireless sensor network.

    PubMed

    Paek, Jeongyeup; Hicks, John; Coe, Sharon; Govindan, Ramesh

    2014-01-01

    This article discusses the experiences from the development and deployment of two image-based environmental monitoring sensor applications using an embedded wireless sensor network. Our system uses low-power image sensors and the Tenet general purpose sensing system for tiered embedded wireless sensor networks. It leverages Tenet's built-in support for reliable delivery of high rate sensing data, scalability and its flexible scripting language, which enables mote-side image compression and the ease of deployment. Our first deployment of a pitfall trap monitoring application at the James San Cannot Mountain Reserve provided us with insights and lessons learned into the deployment of and compression schemes for these embedded wireless imaging systems. Our three month-long deployment of a bird nest monitoring application resulted in over 100,000 images collected from a 19-camera node network deployed over an area of 0.05 square miles, despite highly variable environmental conditions. Our biologists found the on-line, near-real-time access to images to be useful for obtaining data on answering their biological questions. PMID:25171121

  5. Biometrics based novel key distribution solution for body sensor networks.

    PubMed

    Miao, Fen; Jiang, Lei; Li, Ye; Zhang, Yuan-Ting

    2009-01-01

    The security of wireless body sensor network (BSN) is very important to telemedicine and m-healthcare, and it still remains a critical challenge. This paper presents a novel key distribution solution which allows two sensors in one BSN to agree on a changeable cryptographic key. A previously published scheme, fuzzy vault, is firstly applied to secure the random cryptographic key generated from electrocardiographic (ECG) signals. Simulations based on ECG data from MIT PhysioBank database, produce a minimum half total error rate (HTER) of 0.65%, which demonstrates our key distribution solution is promising compared with previous method, with HTER of 4.26%. PMID:19964960

  6. Reversible Photodynamic Chloride-Selective Sensor Based on Photochromic Spiropyran

    PubMed Central

    2012-01-01

    We report here for the first time on a reversible photodynamic bulk optode sensor based on the photoswitching of a spiropyran derivative (Sp). The photoswitching of Sp induces a large basicity increase in the polymeric phase, which triggers the extraction of Cl– and H+. Cl– is stabilized by a lipophilic chloride-selective ionophore inside the membrane, while H+ binds with the open form of Sp and induces a spectral change, hence providing the sensor signal. The system was studied with spectroscopic and electrochemical methods. PMID:23036043

  7. Smartphone-based portable intensity modulated force sensor

    NASA Astrophysics Data System (ADS)

    Negri, Lucas H.; Schiefer, Elberth M.; Paterno, Aleksander S.; Muller, Marcia; Fabris, José L.

    2015-09-01

    This work proposes a low-cost force sensor, based on intensity modulation in an optical fibre. The transducer element is composed of a knot in a single mode fibre embedded to a silicone adhesive cuboid, and can be easily fabricated. A simple sensing scheme is devised by using a visible light source and a CCD camera of a smartphone, allowing implementation costs to be reduced. Experimental results have shown that the sensor presents a linear response and a standard uncertainty of 1:07N within the dynamical range from 0 to 30 N.

  8. Strain calibration of optical FBG-based strain sensors

    NASA Astrophysics Data System (ADS)

    Roths, Johannes; Wilfert, Andre; Kratzer, Peter; Jülich, Florian; Kuttler, Rolf

    2010-09-01

    A facility for strain sensitivity calibration of optical FBG-based strain sensors according to the German VDI/VDE 2660 guideline was established and characterized. Statistical analysis of several calibration measurement series performed with one single type of FBG strain sensor and application technique showed a reproducibility of 0.15%. Strain sensitivities for FBGs inscribed in two different types of optical fibres (GF1B and PR2008) showed significantly different strain sensitivities of k = 0.7885+/-0.0026 and k = 0.7758+/-0.0024, respectively.

  9. VCSEL-based flexible opto-fluidic fluorescence sensors

    NASA Astrophysics Data System (ADS)

    Kang, Dongseok; Gai, Boju; Yoon, Jongseung

    2016-03-01

    Flexible opto-fluidic fluorescence sensors based on microscale vertical cavity surface emitting lasers (micro-VCSELs) and silicon photodiodes (Si-PDs) are demonstrated, where arrays of 850 nm micro-VCSELs and thin film Si-PDs are heterogeneously integrated on a polyethylene terephthalate (PET) substrate by transfer printing, in conjunction with elastomeric fluidic channel. Enabled with optical isolation trenches together with wavelength- and angle-selective spectral filters implemented to suppress the absorption of excitation light, the integrated flexible fluorescence sensors exhibited significantly enhanced signal-to-background ratio, resulting in a maximum sensitivity of 5 × 10-5 wt% of infrared-absorbing organic dyes.

  10. LPG-based sensor for curvature and vibration

    NASA Astrophysics Data System (ADS)

    Nascimento, I. M.; Chesini, G.; Baptista, J. M.; Cordeiro, Cristiano M. B.; Jorge, P. A. S.

    2016-05-01

    A long-period grating (LPG) written on a standard single mode fiber is investigated as a curvature and vibration sensor. It is demonstrated a high sensitivity to applied curvature and the possibility to monitor vibration in a wide range of frequencies from 30 Hz to 2000 Hz. The system was tested using an intensity based interrogation scheme with the LPG sensor operating in the curvature regime. Results have shown a reproducible frequency discrimination in the 30 Hz to 2000 Hz, with resolutions between 11 mHz and 913 mHz. Frequency retrieval could be performed independent of temperature up to 86 °C.

  11. Gas sensors based on semiconducting nanowire field-effect transistors.

    PubMed

    Feng, Ping; Shao, Feng; Shi, Yi; Wan, Qing

    2014-01-01

    One-dimensional semiconductor nanostructures are unique sensing materials for the fabrication of gas sensors. In this article, gas sensors based on semiconducting nanowire field-effect transistors (FETs) are comprehensively reviewed. Individual nanowires or nanowire network films are usually used as the active detecting channels. In these sensors, a third electrode, which serves as the gate, is used to tune the carrier concentration of the nanowires to realize better sensing performance, including sensitivity, selectivity and response time, etc. The FET parameters can be modulated by the presence of the target gases and their change relate closely to the type and concentration of the gas molecules. In addition, extra controls such as metal decoration, local heating and light irradiation can be combined with the gate electrode to tune the nanowire channel and realize more effective gas sensing. With the help of micro-fabrication techniques, these sensors can be integrated into smart systems. Finally, some challenges for the future investigation and application of nanowire field-effect gas sensors are discussed. PMID:25232915

  12. Planar integrated polymer-based optical strain sensor

    NASA Astrophysics Data System (ADS)

    Kelb, Christian; Reithmeier, Eduard; Roth, Bernhard

    2014-03-01

    In this work we present a new type of optical strain sensor that can be manufactured by MEMS typical processes such as photolithography or by hot embossing. Such sensors can be of interest for a range of new applications in structural health monitoring for buildings and aircraft, process control and life science. The approach aims at high sensitivity and dynamic range for 1D and 2D sensing of mechanical strain and can also be extended to quantities such as pressure, force, and humidity. The sensor consists of an array of planar polymer-based multimode waveguides whose output light is guided through a measurement area and focused onto a second array of smaller detection waveguides by using micro-optical elements. Strain induced in the measurement area varies the distance between the two waveguide arrays, thus, changing the coupling efficiency. This, in turn, leads to a variation in output intensity or wavelength which is monitored. We performed extensive optical simulations in order to identify the optimal sensor layout with regard to either resolution or measurement range or both. Since the initial approach relies on manufacturing polymer waveguides with cross sections between 20×20 μm2 and 100×100 μm2 the simulations were carried out using raytracing models. For the readout of the sensor a simple fitting algorithm is proposed.

  13. Carbon Nanotube-Based Structural Health Monitoring Sensors

    NASA Technical Reports Server (NTRS)

    Wincheski, Russell; Jordan, Jeffrey; Oglesby, Donald; Watkins, Anthony; Patry, JoAnne; Smits, Jan; Williams, Phillip

    2011-01-01

    Carbon nanotube (CNT)-based sensors for structural health monitoring (SHM) can be embedded in structures of all geometries to monitor conditions both inside and at the surface of the structure to continuously sense changes. These CNTs can be manipulated into specific orientations to create small, powerful, and flexible sensors. One of the sensors is a highly flexible sensor for crack growth detection and strain field mapping that features a very dense and highly ordered array of single-walled CNTs. CNT structural health sensors can be mass-produced, are inexpensive, can be packaged in small sizes (0.5 micron(sup 2)), require less power than electronic or piezoelectric transducers, and produce less waste heat per square centimeter than electronic or piezoelectric transducers. Chemically functionalized lithographic patterns are used to deposit and align the CNTs onto metallic electrodes. This method consistently produces aligned CNTs in the defined locations. Using photo- and electron-beam lithography, simple Cr/Au thin-film circuits are patterned onto oxidized silicon substrates. The samples are then re-patterned with a CNT-attracting, self-assembled monolayer of 3-aminopropyltriethoxysilane (APTES) to delineate the desired CNT locations between electrodes. During the deposition of the solution-suspended single- wall CNTs, the application of an electric field to the metallic contacts causes alignment of the CNTs along the field direction. This innovation is a prime candidate for smart skin technologies with applications ranging from military, to aerospace, to private industry.

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

    PubMed Central

    Feng, Ping; Shao, Feng; Shi, Yi; Wan, Qing

    2014-01-01

    One-dimensional semiconductor nanostructures are unique sensing materials for the fabrication of gas sensors. In this article, gas sensors based on semiconducting nanowire field-effect transistors (FETs) are comprehensively reviewed. Individual nanowires or nanowire network films are usually used as the active detecting channels. In these sensors, a third electrode, which serves as the gate, is used to tune the carrier concentration of the nanowires to realize better sensing performance, including sensitivity, selectivity and response time, etc. The FET parameters can be modulated by the presence of the target gases and their change relate closely to the type and concentration of the gas molecules. In addition, extra controls such as metal decoration, local heating and light irradiation can be combined with the gate electrode to tune the nanowire channel and realize more effective gas sensing. With the help of micro-fabrication techniques, these sensors can be integrated into smart systems. Finally, some challenges for the future investigation and application of nanowire field-effect gas sensors are discussed. PMID:25232915

  15. Pressure sensor based on flexible photonic crystal membrane.

    PubMed

    Karrock, Torben; Gerken, Martina

    2015-12-01

    We demonstrate a pressure sensor based on deformation of a periodically nanostructured Bragg grating waveguide on a flexible 50 µm polydimethylsiloxane membrane and remote optical read out. A pressure change causes deformation of this 2 mm diameter photonic crystal membrane sealing a reference volume. The resulting shift of the guided mode resonances is observed by a remote camera as localized color change. Crossed polarization filters are employed for enhancing the visibility of the guided mode resonances. Pressure values are calculated from the intensity change in the green color channel using a calibration curve in the range of 2000 Pa to 4000 Pa. A limit of detection (LOD) of 160 Pa is estimated. This LOD combined with the small size of the sensor and its biocompatibility render it promising for application as an implantable intraocular pressure sensor. PMID:26713204

  16. Adaptive wavefront sensor based on the Talbot effect

    NASA Astrophysics Data System (ADS)

    Podanchuk, Dmytro V.; Kurashov, Vitaliy N.; Kovalenko, Andrey V.; Dan'ko, Volodymyr P.; Kotov, Myhailo M.; Goloborodko, Nataliya S.

    2015-11-01

    The possibilities of wavefront curvature measuring by Talbot sensor are theoretically and experimentally investigated. A new method of wavefront aberrations measurement is proposed and demonstrated. It is based on the observation of the Talbot effect when the diffraction grating is adapted to the wavefront curvature of the analyzed wave. Herewith, the observation plane stay fixed and corresponds to the Talbot length for a plane wave. It is shown that the measurement range can be made several times wider, with the help of the adaptive Talbot sensor, by retaining the required angular sensitivity. A possibility of self-reproduction of the rectangular grating (with different periods along the axes) by the astigmatic wavefront is experimentally demonstrated. The possibility of the experimental realization of the adaptive Talbot sensor using the dynamic spatial light modulator is demonstrated.

  17. Hydrogen Gas Sensors Based on Semiconductor Oxide Nanostructures

    PubMed Central

    Gu, Haoshuang; Wang, Zhao; Hu, Yongming

    2012-01-01

    Recently, the hydrogen gas sensing properties of semiconductor oxide (SMO) nanostructures have been widely investigated. In this article, we provide a comprehensive review of the research progress in the last five years concerning hydrogen gas sensors based on SMO thin film and one-dimensional (1D) nanostructures. The hydrogen sensing mechanism of SMO nanostructures and some critical issues are discussed. Doping, noble metal-decoration, heterojunctions and size reduction have been investigated and proved to be effective methods for improving the sensing performance of SMO thin films and 1D nanostructures. The effect on the hydrogen response of SMO thin films and 1D nanostructures of grain boundary and crystal orientation, as well as the sensor architecture, including electrode size and nanojunctions have also been studied. Finally, we also discuss some challenges for the future applications of SMO nanostructured hydrogen sensors. PMID:22778599

  18. Gas sensors based on silicon devices with a porous layer

    NASA Astrophysics Data System (ADS)

    Barillaro, G.; Diligenti, A.; Nannini, A.; Strambini, L. M.

    2005-06-01

    In this work two silicon devices, that is a FET and a p crystalline silicon resistor having porous silicon as adsorbing layer are presented as gas sensors. Owing to they are easily integrable with silicon electronics, these devices could represent an improvement of the functionality of silicon for sensor applications. Unlike other porous silicon-based sensors, in this case the sensing variable is a current flowing in the crystalline silicon, so that the porous silicon film has only the function of adsorbing layer and its properties, electrical or optical, are not directly involved in the measurement. The fabrication processes and an electrical characterization in presence of isopropanol vapors are presented and discussed for both devices.

  19. Space magnetometer based on an anisotropic magnetoresistive hybrid sensor

    NASA Astrophysics Data System (ADS)

    Brown, P.; Whiteside, B. J.; Beek, T. J.; Fox, P.; Horbury, T. S.; Oddy, T. M.; Archer, M. O.; Eastwood, J. P.; Sanz-Hernández, D.; Sample, J. G.; Cupido, E.; O'Brien, H.; Carr, C. M.

    2014-12-01

    We report on the design and development of a low resource, dual sensor vector magnetometer for space science applications on very small spacecraft. It is based on a hybrid device combining an orthogonal triad of commercial anisotropic magnetoresistive (AMR) sensors with a totem pole H-Bridge drive on a ceramic substrate. The drive enables AMR operation in the more sensitive flipped mode and this is achieved without the need for current spike transmission down a sensor harness. The magnetometer has sensitivity of better than 3 nT in a 0-10 Hz band and a total mass of 104 g. Three instruments have been launched as part of the TRIO-CINEMA space weather mission, inter-calibration against the International Geomagnetic Reference Field model makes it possible to extract physical signals such as field-aligned current deflections of 20-60 nT within an approximately 45 000 nT ambient field.

  20. Pressure sensor based on flexible photonic crystal membrane

    PubMed Central

    Karrock, Torben; Gerken, Martina

    2015-01-01

    We demonstrate a pressure sensor based on deformation of a periodically nanostructured Bragg grating waveguide on a flexible 50 µm polydimethylsiloxane membrane and remote optical read out. A pressure change causes deformation of this 2 mm diameter photonic crystal membrane sealing a reference volume. The resulting shift of the guided mode resonances is observed by a remote camera as localized color change. Crossed polarization filters are employed for enhancing the visibility of the guided mode resonances. Pressure values are calculated from the intensity change in the green color channel using a calibration curve in the range of 2000 Pa to 4000 Pa. A limit of detection (LOD) of 160 Pa is estimated. This LOD combined with the small size of the sensor and its biocompatibility render it promising for application as an implantable intraocular pressure sensor. PMID:26713204

  1. Fabrication and Characterization of a Nanocoax-Based Electrochemical Sensor

    NASA Astrophysics Data System (ADS)

    Rizal, Binod; Archibald, Michelle M.; Naughton, Jeffrey R.; Connolly, Timothy; Shepard, Stephen C.; Burns, Michael J.; Chiles, Thomas C.; Naughton, Michael J.

    2014-03-01

    We used an imprint lithography process to fabricate three dimensional electrochemical sensors comprising arrays of vertically-oriented coaxial electrodes, with the coax cores and shields serving as working and counter electrodes, respectively, and with nanoscale separation gaps.[2] Arrays of devices with different electrode gaps (coax annuli) were prepared, yielding increasing sensitivity with decreasing annulus thickness. A coax-based sensor with a 100 nm annulus was found to have sensitivity 100 times greater than that of a conventional planar sensor control, which had millimeter-scale electrode gap spacing. We suggest that this enhancement is due to an increase in the diffusion of molecules between electrodes, which improves the current per unit surface area compared to the planar device. Supported by NIH (National Cancer Institute and the National Institute of Allergy and Infectious Diseases).

  2. A FBG-based, temperature-insensitive vibration sensor

    NASA Astrophysics Data System (ADS)

    Zhou, Wenjun; Dong, Xinyong; Li, Lan; Ni, Kai; Jin, Yongxing

    2009-08-01

    In this paper, a novel temperature-insensitive vibration sensor based on a FBG is demonstrated. The FBG is glued in a slanted direction onto the lateral side of a right-angled triangle cantilever beam with an eccentric gear installed on its free end. Vertical vibration applied by the eccentric gear to the cantilever beam leads to a uniform bending along the beam length. As a result, the FBG is chirped and its reflection bandwidth and power change periodically with the variation of the displacement of the free end. The experimental results were compared with the data of vibration measurement of a conventional electrical strain sensor. Furthermore, this sensor is temperature insensitive, owning to the temperatureindependence nature of reflection bandwidth and power of the FBG.

  3. Acoustic vibration sensor based on nonadiabatic tapered fibers.

    PubMed

    Xu, Ben; Li, Yi; Sun, Miao; Zhang, Zhen-Wei; Dong, Xin-Yong; Zhang, Zai-Xuan; Jin, Shang-Zhong

    2012-11-15

    A simple and low-cost vibration sensor based on single-mode nonadiabatic fiber tapers is proposed and demonstrated. The environmental vibrations can be detected by demodulating the transmission loss of the nonadiabatic fiber taper. Theoretical simulations show that the transmission loss is related to the microbending of the fiber taper induced by vibrations. Unlike interferometric sensors, this vibration sensor does not need any feedback loop to control the quadrature point to obtain a stable performance. In addition, it has no requirement for the coherence of the light source and is insensitive to temperature changes. Experimental results show that this sensing system has a wide frequency response range from a few hertz to tens of kilohertz with the maximal signal to noise ratio up to 73 dB. PMID:23164907

  4. Optical sensor based on a single CdS nanobelt.

    PubMed

    Li, Lei; Yang, Shuming; Han, Feng; Wang, Liangjun; Zhang, Xiaotong; Jiang, Zhuangde; Pan, Anlian

    2014-01-01

    In this paper, an optical sensor based on a cadmium sulfide (CdS) nanobelt has been developed. The CdS nanobelt was synthesized by the vapor phase transportation (VPT) method. X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) results revealed that the nanobelt had a hexagonal wurtzite structure of CdS and presented good crystal quality. A single nanobelt Schottky contact optical sensor was fabricated by the electron beam lithography (EBL) technique, and the device current-voltage results showed back-to-back Schottky diode characteristics. The photosensitivity, dark current and the decay time of the sensor were 4 × 10⁴, 31 ms and 0.2 pA, respectively. The high photosensitivity and the short decay time were because of the exponential dependence of photocurrent on the number of the surface charges and the configuration of the back to back Schottky junctions. PMID:24763211

  5. Highly sensitive DNA sensor based on polypyrrole nanowire

    NASA Astrophysics Data System (ADS)

    Mai, Anh Tuan; Duc, Thanh Pham; Thi, Xuan Chu; Nguyen, Minh Hieu; Nguyen, Hoang Hai

    2014-08-01

    This paper describes the development of a DNA sensor based on polypyrrole nanowire. By using potentiostatic technique, in the presence of gelatin as the soft mold, the polypyrrole nanowires were synthesized on the surface of the micro-sensor. The surface enhanced Raman spectroscopy shows that the Nsbnd H ends of the polypyrrole nanowires orientate upward from the surface facilitating the DNA probe immobilization through the simple linkage with the phosphate groups of the probe DNA. The label-free signal readout was carried out by lock-in amplifier technique. The response time of the DNA sensor is 10 s and the measurement time was 5 min. The lowest detectable concentration of Escherichia coli DNA was 0.1 nM.

  6. Space magnetometer based on an anisotropic magnetoresistive hybrid sensor.

    PubMed

    Brown, P; Whiteside, B J; Beek, T J; Fox, P; Horbury, T S; Oddy, T M; Archer, M O; Eastwood, J P; Sanz-Hernández, D; Sample, J G; Cupido, E; O'Brien, H; Carr, C M

    2014-12-01

    We report on the design and development of a low resource, dual sensor vector magnetometer for space science applications on very small spacecraft. It is based on a hybrid device combining an orthogonal triad of commercial anisotropic magnetoresistive (AMR) sensors with a totem pole H-Bridge drive on a ceramic substrate. The drive enables AMR operation in the more sensitive flipped mode and this is achieved without the need for current spike transmission down a sensor harness. The magnetometer has sensitivity of better than 3 nT in a 0-10 Hz band and a total mass of 104 g. Three instruments have been launched as part of the TRIO-CINEMA space weather mission, inter-calibration against the International Geomagnetic Reference Field model makes it possible to extract physical signals such as field-aligned current deflections of 20-60 nT within an approximately 45,000 nT ambient field. PMID:25554336

  7. Personal Navigation Algorithms Based on Wireless Networks and Inertial Sensors

    NASA Astrophysics Data System (ADS)

    Kaňa, Zdenek; Bradáč, Zdenek; Fiedler, Petr

    2014-08-01

    The work aims at a development of positioning algorithm suitable for low-cost indoor or urban pedestrian navigation application. The sensor fusion was applied to increase the localization accuracy. Due to required low application cost only low grade inertial sensors and wireless network based ranging were taken into account. The wireless network was assumed to be preinstalled due to other required functionality (for example: building control) therefore only received signal strength (RSS) range measurement technique was considered. Wireless channel loss mapping method was proposed to overcome the natural uncertainties and restrictions in the RSS range measurements The available sensor and environment models are summarized first and the most appropriate ones are selected secondly. Their effective and novel application in the navigation task, and favorable fusion (Particle filtering) of all available information are the main objectives of this thesis.

  8. Surface Coverage in Wireless Sensor Networks Based on Delaunay Tetrahedralization

    NASA Astrophysics Data System (ADS)

    Ribeiro, M. G.; Neves, L. A.; Pinto, A. R.; Nascimento, M. Z.; Zafalon, G. F. D.; Valêncio, C.

    2015-01-01

    In this work is presented a new method for sensor deployment on 3D surfaces. The method was structured on different steps. The first one aimed discretizes the relief of interest with Delaunay algorithm. The tetrahedra and relative values (spatial coordinates of each vertex and faces) were input to construction of 3D Voronoi diagram. Each circumcenter was calculated as a candidate position for a sensor node: the corresponding circular coverage area was calculated based on a radius r. The r value can be adjusted to simulate different kinds of sensors. The Dijkstra algorithm and a selection method were applied to eliminate candidate positions with overlapped coverage areas or beyond of surface of interest. Performance evaluations measures were defined using coverage area and communication as criteria. The results were relevant, once the mean coverage rate achieved on three different surfaces were among 91% and 100%.

  9. A Taste Sensor Based on a Carbon Nanotube

    NASA Astrophysics Data System (ADS)

    Takagi, Keisuke; Hirata, Takamichi; Akiya, Masahiro

    A taste sensor consisting of a back-gate type field effect transistor(FET) chip based on carbon nanotube compound materials[poly(ethylene glycol)(PEG)-grafted single-walled carbon nanotubes(PEG-SWNTs)] was developed. The results of impedance measurements for five tastes (sourness, saltiness, bitterness, sweetness, and umami), are shown much difference for specific tastes which are difficult to identify by using Langmuir-Blodgett(LB)film. Moreover, the sensor is able to distinguish most of the experimental taste materials with a short response time. Characteristics of the sensor involve in taste material concentration , initial impedance and frequency characteristics. A clear difference is observed over five basic taste materials.

  10. A temperature sensor based on a whispering gallery mode resonator

    NASA Astrophysics Data System (ADS)

    Yu, L.; Fernicola, V.

    2013-09-01

    This paper deals with a microwave temperature sensor based on a whispering gallery mode (WGM) resonator whose dielectric medium is a cylindrical sapphire crystal. The performance as temperature sensor were investigated a three WGMs resonant frequencies over the temperature range from -40 °C to 85 °C. It was found that the quality factor for these WGMs can be in excess of 1.7ṡ105, potentially enabling high-resolution measurements. The temperature repeatability, stability, hysteresis, frequency-vs-temperature sensitivity of the WGM temperature sensor are reported. Moreover, two sapphires, which have the same nominal characteristics, were investigated in order to assess the system reproducibility and the results reported.

  11. Fiber pressure sensors based on periodical mode coupling effects

    NASA Astrophysics Data System (ADS)

    Lotem, Haim; Wang, Wen C.; Wang, Michael; Schaafsma, David; Skolnick, Bob; Grebel, Haim

    2005-05-01

    Fiber optic sensor technology offers the possibility of implementing low weight, high performance and cost effective health and damage assessment for infrastructure elements. Common fiber sensors are based on the effect of external action on the spectral response of a Fabry-Perot or a Bragg grating section, or on the modal dynamics in multimode (MM) fiber. In the latter case, the fiber itself acts as the sensor, giving it the potential for large range coverage. We were interested in this type of sensor because of its cost advantage in monitoring structural health. In the course of the research, a new type of a rugged modal filter device, based on off-center splicing, was developed. This device, in combination with a MM fiber, was found to be a potential single point-pressure sensing device. Additionally, by translating the pressing point along a MM sensing fiber with a constant load and speed, a sinusoidal intensity modulation was observed. This harmonic behavior, during load translation, is explained by the theory of mode coupling and dispersion. The oscillation period, L~0.43. mm, obtained at 980 nm in a Corning SMF-28 fiber, corresponds to the wavevector difference, Db, between the two-coupled modes, by L = 2p/Db. An additional outcome of the present research is the observation that the response of the loaded MM fiber is strongly dependent on the polarization state of the light traveling along the MM fiber due to different response of the modes to polarization active elements. Our main conclusions are that in MM fiber optic sensor design, special cautions need to be taken in order to stabilize the system, and that the sensitivity along a MM fiber sensor is periodic with a period of ~ 0.4 - 0.5 mm, depending on various fiber parameters and excited modes.

  12. Magnetic field sensor using a polymer-based vibrator

    NASA Astrophysics Data System (ADS)

    Wu, Jiang; Hasebe, Kazuhiko; Mizuno, Yosuke; Tabaru, Marie; Nakamura, Kentaro

    2016-09-01

    In this technical note, a polymer-based magnetic sensor with a high resolution was devised for sensing the high magnetic field. It consisted of a bimorph (vibrator) made of poly (phenylene sulfide) (PPS) and a phosphor-bronze foil glued on the free end of the bimorph. According to Faraday’s law of induction, when a magnetic field in the direction perpendicular to the bimorph was applied, the foil cut the magnetic flux, and generated an alternating voltage across the leads at the natural frequency of the bimorph. Because PPS has low mechanical loss, low elastic modulus, and low density, high vibration velocity can be achieved if it is employed as the elastomer of the bimorph. The devised sensor was tested in the magnetic field range of 0.1–570 mT and exhibited a minimum detectable magnetic field of 0.1 mT. At a zero-to-peak driving voltage of 60 V, the sensitivity of the PPS-based magnetic sensor reached 10.5 V T‑1, which was 1.36 times the value of the aluminum-based magnetic sensor with the same principle and dimensions.

  13. Chain-based communication in cylindrical underwater wireless sensor networks.

    PubMed

    Javaid, Nadeem; Jafri, Mohsin Raza; Khan, Zahoor Ali; Alrajeh, Nabil; Imran, Muhammad; Vasilakos, Athanasios

    2015-01-01

    Appropriate network design is very significant for Underwater Wireless Sensor Networks (UWSNs). Application-oriented UWSNs are planned to achieve certain objectives. Therefore, there is always a demand for efficient data routing schemes, which can fulfill certain requirements of application-oriented UWSNs. These networks can be of any shape, i.e., rectangular, cylindrical or square. In this paper, we propose chain-based routing schemes for application-oriented cylindrical networks and also formulate mathematical models to find a global optimum path for data transmission. In the first scheme, we devise four interconnected chains of sensor nodes to perform data communication. In the second scheme, we propose routing scheme in which two chains of sensor nodes are interconnected, whereas in third scheme single-chain based routing is done in cylindrical networks. After finding local optimum paths in separate chains, we find global optimum paths through their interconnection. Moreover, we develop a computational model for the analysis of end-to-end delay. We compare the performance of the above three proposed schemes with that of Power Efficient Gathering System in Sensor Information Systems (PEGASIS) and Congestion adjusted PEGASIS (C-PEGASIS). Simulation results show that our proposed 4-chain based scheme performs better than the other selected schemes in terms of network lifetime, end-to-end delay, path loss, transmission loss, and packet sending rate. PMID:25658394

  14. Chain-Based Communication in Cylindrical Underwater Wireless Sensor Networks

    PubMed Central

    Javaid, Nadeem; Jafri, Mohsin Raza; Khan, Zahoor Ali; Alrajeh, Nabil; Imran, Muhammad; Vasilakos, Athanasios

    2015-01-01

    Appropriate network design is very significant for Underwater Wireless Sensor Networks (UWSNs). Application-oriented UWSNs are planned to achieve certain objectives. Therefore, there is always a demand for efficient data routing schemes, which can fulfill certain requirements of application-oriented UWSNs. These networks can be of any shape, i.e., rectangular, cylindrical or square. In this paper, we propose chain-based routing schemes for application-oriented cylindrical networks and also formulate mathematical models to find a global optimum path for data transmission. In the first scheme, we devise four interconnected chains of sensor nodes to perform data communication. In the second scheme, we propose routing scheme in which two chains of sensor nodes are interconnected, whereas in third scheme single-chain based routing is done in cylindrical networks. After finding local optimum paths in separate chains, we find global optimum paths through their interconnection. Moreover, we develop a computational model for the analysis of end-to-end delay. We compare the performance of the above three proposed schemes with that of Power Efficient Gathering System in Sensor Information Systems (PEGASIS) and Congestion adjusted PEGASIS (C-PEGASIS). Simulation results show that our proposed 4-chain based scheme performs better than the other selected schemes in terms of network lifetime, end-to-end delay, path loss, transmission loss, and packet sending rate. PMID:25658394

  15. Drug and alcohol abuse: the bases for employee assistance programs in the nuclear-utility industry

    SciTech Connect

    Radford, L.R.; Rankin, W.L.; Barnes, V.; McGuire, M.V.; Hope, A.M.

    1983-07-01

    This report describes the nature, prevalence, and trends of drug and alcohol abuse among members of the US adult population and among personnel in non-nuclear industries. Analogous data specific to the nuclear utility industry are not available, so these data were gathered in order to provide a basis for regulatory planning. The nature, prevalence, and trend inforamtion was gathered using a computerized literature, telephone discussions with experts, and interviews with employee assistance program representatives from the Seattle area. This report also evaluates the possible impacts that drugs and alcohol might have on nuclear-related job performance, based on currently available nuclear utility job descriptions and on the scientific literature regarding the impairing effects of drugs and alcohol on human performance. Employee assistance programs, which can be used to minimize or eliminate job performance decrements resulting from drug or alcohol abuse, are also discussed.

  16. Alcohol marketing, drunkenness, and problem drinking among Zambian youth: findings from the 2004 Global School-Based Student Health Survey.

    PubMed

    Swahn, Monica H; Ali, Bina; Palmier, Jane B; Sikazwe, George; Mayeya, John

    2011-01-01

    This study examines the associations between alcohol marketing strategies, alcohol education including knowledge about dangers of alcohol and refusal of alcohol, and drinking prevalence, problem drinking, and drunkenness. Analyses are based on the Global School-Based Student Health Survey (GSHS) conducted in Zambia (2004) of students primarily 11 to 16 years of age (N = 2257). Four statistical models were computed to test the associations between alcohol marketing and education and alcohol use, while controlling for possible confounding factors. Alcohol marketing, specifically through providing free alcohol through a company representative, was associated with drunkenness (AOR = 1.49; 95% CI: 1.09-2.02) and problem drinking (AOR = 1.41; 95% CI: 1.06-1.87) among youth after controlling for demographic characteristics, risky behaviors, and alcohol education. However, alcohol education was not associated with drunkenness or problem drinking. These findings underscore the importance of restricting alcohol marketing practices as an important policy strategy for reducing alcohol use and its dire consequences among vulnerable youth. PMID:21647354

  17. Compressive sensing based wireless sensor for structural health monitoring

    NASA Astrophysics Data System (ADS)

    Bao, Yuequan; Zou, Zilong; Li, Hui

    2014-03-01

    Data loss is a common problem for monitoring systems based on wireless sensors. Reliable communication protocols, which enhance communication reliability by repetitively transmitting unreceived packets, is one approach to tackle the problem of data loss. An alternative approach allows data loss to some extent and seeks to recover the lost data from an algorithmic point of view. Compressive sensing (CS) provides such a data loss recovery technique. This technique can be embedded into smart wireless sensors and effectively increases wireless communication reliability without retransmitting the data. The basic idea of CS-based approach is that, instead of transmitting the raw signal acquired by the sensor, a transformed signal that is generated by projecting the raw signal onto a random matrix, is transmitted. Some data loss may occur during the transmission of this transformed signal. However, according to the theory of CS, the raw signal can be effectively reconstructed from the received incomplete transformed signal given that the raw signal is compressible in some basis and the data loss ratio is low. This CS-based technique is implemented into the Imote2 smart sensor platform using the foundation of Illinois Structural Health Monitoring Project (ISHMP) Service Tool-suite. To overcome the constraints of limited onboard resources of wireless sensor nodes, a method called random demodulator (RD) is employed to provide memory and power efficient construction of the random sampling matrix. Adaptation of RD sampling matrix is made to accommodate data loss in wireless transmission and meet the objectives of the data recovery. The embedded program is tested in a series of sensing and communication experiments. Examples and parametric study are presented to demonstrate the applicability of the embedded program as well as to show the efficacy of CS-based data loss recovery for real wireless SHM systems.

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

    NASA Astrophysics Data System (ADS)

    Nallon, Eric C.

    chemiresistor device and used as a chemical sensor, where its resistance is temporarily modified while exposed to chemical compounds. The inherent, broad selective nature of graphene is demonstrated by testing a sensor against a diverse set of volatile organic compounds and also against a set of chemically similar compounds. The sensor exhibits excellent selectivity and is capable of achieving high classification accuracies. The kinetics of the sensor's response are further investigated revealing a relationship between the transient behavior of the response curve and physiochemical properties of the compounds, such as the molar mass and vapor pressure. This kinetic information is also shown to provide important information for further pattern recognition and classification, which is demonstrated by increased classification accuracy of very similar compounds. Covalent modification of the graphene surface is demonstrated by means of plasma treatment and free radical exchange, and sensing performance compared to an unmodified graphene sensor. Finally, the first example of a graphene-based, cross-reactive chemical sensor array is demonstrated by applying various polymers as coatings over an array of graphene sensors. The sensor array is tested against a variety of compounds, including the complex odor of Scotch whiskies, where it is capable of perfect classification of 10 Scotch whiskey variations.

  19. Alcohol vapor sensory properties of nanostructured conjugated polymers

    NASA Astrophysics Data System (ADS)

    Bearzotti, Andrea; Macagnano, Antonella; Pantalei, Simone; Zampetti, Emiliano; Venditti, Iole; Fratoddi, Ilaria; Vittoria Russo, Maria

    2008-11-01

    The response to relative humidity (RH) and alcohol vapors of resistive-type sensors based on nanobeads of conjugated polymers, namely polyphenylacetylene (PPA) and copolymer poly[phenylacetylene-(co-2-hydroxyethyl methacrylate)] (P(PA/HEMA)), were investigated. Sensors based on ordered arrays of these nanostructured polymeric materials showed stable and reproducible current intensity variations in the range 10-90% of relative humidity at room temperature. Both polymers also showed sensitivity to aliphatic chain primary alcohols, and a fine tuning of the sensor response was obtained by varying the chain length of the alcohol in relation to the polarity. The nanostructured feature of polymeric-based membranes seems to have an effect on the sensing response and an enhancement of the sensitivity was observed for the response to water and alcohol vapor variations with respect to previous studies based on amorphous polyphenylacetylene. High stability of the polymeric nanostructured membranes was detected with no aging after two weeks in continuum stressing measurement conditions.

  20. Fundamentals of Enzyme-Based Sensors

    NASA Astrophysics Data System (ADS)

    Moreno-Bondi, María C.; Benito-Peña, Elena

    One of the mayor outbreaks in the development of analytical measurement techniques was the introduction, in the mid-twentieth century, of bioprobes for the analysis of chemical and biochemical compounds in real samples. The first devices, developed in the 1950's and 1960's by Clark et al. were based on electrochemical measurements and allowed the determination of oxygen and glucose in tissues and blood samples. Later on, in the 1970's, optical transduction was coupled to enzymatically-catalyzed reactions3 and since those early days the field of application of optical biosensors has broaden up considerably. According to the definition proposed by the International Union of Pure and Applied Chemistry (IUPAC): "A biosensor is a self-contained integrated device which is capable of providing specific quantitative or semi-quantitative analytical information using a biological recognition element (biochemical receptor) which is in direct spatial contact with a transducer element. A biosensor should be clearly distinguished from a bioanalytical system, which requires additional processing steps, such as reagent addition. Furthermore, a biosensor should be distinguished from a bioprobe which is either disposable after one measurement, i.e. single use, or unable to continuously monitor the analyte concentration". The general scheme of a biosensor configuration is shown in Figure 1. Biosensors that include transducers based on integrated circuit microchips are known as biochips.

  1. A satellite-based radar wind sensor

    NASA Technical Reports Server (NTRS)

    Xin, Weizhuang

    1991-01-01

    The objective is to investigate the application of Doppler radar systems for global wind measurement. A model of the satellite-based radar wind sounder (RAWS) is discussed, and many critical problems in the designing process, such as the antenna scan pattern, tracking the Doppler shift caused by satellite motion, and backscattering of radar signals from different types of clouds, are discussed along with their computer simulations. In addition, algorithms for measuring mean frequency of radar echoes, such as the Fast Fourier Transform (FFT) estimator, the covariance estimator, and the estimators based on autoregressive models, are discussed. Monte Carlo computer simulations were used to compare the performance of these algorithms. Anti-alias methods are discussed for the FFT and the autoregressive methods. Several algorithms for reducing radar ambiguity were studied, such as random phase coding methods and staggered pulse repitition frequncy (PRF) methods. Computer simulations showed that these methods are not applicable to the RAWS because of the broad spectral widths of the radar echoes from clouds. A waveform modulation method using the concept of spread spectrum and correlation detection was developed to solve the radar ambiguity. Radar ambiguity functions were used to analyze the effective signal-to-noise ratios for the waveform modulation method. The results showed that, with suitable bandwidth product and modulation of the waveform, this method can achieve the desired maximum range and maximum frequency of the radar system.

  2. Design, Simulation and Experimental Characteristics of Hydrogel-based Piezoresistive pH Sensors

    NASA Astrophysics Data System (ADS)

    Trinh, Thong Quang; Sorber, Jorge; Gerlach, Gerald

    This paper presents the investigations of a novel type of piezoresistive pH sensors exploiting the chemo-mechanical energy conversion due to hydrogel swelling. pH-sensitive poly(vinyl alcohol)-poly(acrylic acid) (PVA-PAA) hydrogel is used for this aim. The pH sensor has been designed including a commercial piezoresistive pressure sensor chip, a hydrogel layer, and a rigid grid. Behaviour of pH sensor under swelling of polymer hydrogel has been simulated using finite element method (ANSYS). The sensor simulations have been performed using the experimental material parameters of PVA-PAA hydrogel. The sensor characteristics including the silicon diaphragm deflection and output voltage have been measured. There were good relative agreements between simulations and experimental results.

  3. An oxidase-based electrochemical fluidic sensor with high-sensitivity and low-interference by on-chip oxygen manipulation.

    PubMed

    Radhakrishnan, Nitin; Park, Jongwon; Kim, Chang-Soo

    2012-01-01

    Utilizing a simple fluidic structure, we demonstrate the improved performance of oxidase-based enzymatic biosensors. Electrolysis of water is utilized to generate bubbles to manipulate the oxygen microenvironment close to the biosensor in a fluidic channel. For the proper enzyme reactions to occur, a simple mechanical procedure of manipulating bubbles was developed to maximize the oxygen level while minimizing the pH change after electrolysis. The sensors show improved sensitivities based on the oxygen dependency of enzyme reaction. In addition, this oxygen-rich operation minimizes the ratio of electrochemical interference signal by ascorbic acid during sensor operation (i.e., amperometric detection of hydrogen peroxide). Although creatinine sensors have been used as the model system in this study, this method is applicable to many other biosensors that can use oxidase enzymes (e.g., glucose, alcohol, phenol, etc.) to implement a viable component for in-line fluidic sensor systems. PMID:23012527

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Development of a soil detector based on an optical sensor

    NASA Astrophysics Data System (ADS)

    Zheng, Lihua; Pan, Luan; Li, Minzan; An, Xiaofei

    2008-12-01

    An estimation model of the soil organic matter content has been built based on NIR spectroscopy and a portable soil organic matter detector based on optical sensor is developed. The detector uses a micro processor 89S52 as the Micro Controller Unit (MCU) and consists of an optical system and a control system. The optical system includes a 850nm near-infrared lamp-house, a lamp-house driving-circuit, a Y type optical fiber, a probe, and a photoelectric sensor. The control system includes an amplified circuit, an A/D circuit, a display circuit with LCD, and a storage circuit with USB interface. Firstly the single waveband optical signal from the near-infrared lamp-house is transferred to the surface of the target soil via the incidence fibers. Then the reflected optical signal is collected and transferred to photoelectric sensor, where the optical signal is conveyed to the electrical signal. Subsequently, the obtained electrical signal is processed by 89S52 MCU. Finally, the calculated soil organic matter content is displayed on the LCD and stored in the USB disk. The calibration experiment using the estimation model of the soil organic matter is conducted. The decision coefficient (R2) reaches 0.9839 between the measured data by the soil organic matter sensor and by the laboratory chemistry method.

  6. Smart sensor-based geospatial architecture for dike monitoring

    NASA Astrophysics Data System (ADS)

    Herle, S.; Becker, R.; Blankenbach, J.

    2016-04-01

    Artificial hydraulic structures like dams or dikes used for water level regulations or flood prevention are continuously under the influence of the weather and variable river regimes. Thus, ongoing monitoring and simulation is crucial in order to determine the inner condition. Potentially life-threatening situations, in extreme case a failure, must be counteracted by all available means. Nowadays flood warning systems rely exclusively on water level forecast without considering the state of the structure itself. Area-covering continuous knowledge of the inner state including time dependent changes increases the capability of recognizing and locating vulnerable spots for early treatment. In case of a predicted breach, advance warning time for alerting affected citizens can be extended. Our approach is composed of smart sensors integrated in a service-oriented geospatial architecture to monitor and simulate artificial hydraulic structures continuously. The sensors observe the inner state of the construction like the soil moisture or the stress and deformation over time but also various external influences like water levels or wind speed. They are interconnected in distributed network architecture by a so-called sensor bus system based on lightweight protocols like Message Queue Telemetry Transport for Sensor Networks (MQTT-SN). These sensor data streams are transferred into an OGC Sensor Web Enablement (SWE) data structure providing high-level geo web services to end users. Bundled with 3rd party geo web services (WMS etc.) powerful processing and simulation tools can be invoked using the Web Processing Service (WPS) standard. Results will be visualized in a geoportal allowing user access to all information.

  7. Fiber-Optic Hydrogen Sensors Based upon Chromogenic Materials

    NASA Astrophysics Data System (ADS)

    Pitts, Roland

    2002-03-01

    The development of lightweight, low cost, inherently safe, reliable hydrogen sensors is crucial to the development of an infrastructure for a hydrogen-based economy. Since the involvement of hydrogen in the Hindenburg disaster (May 7, 1937), the public perception is that hydrogen is dangerous to use, store, and handle. It will require extraordinary safety measures to ensure the public that hydrogen leaks can be detected and controlled early. Detection requires sensors to be arrayed in locations where explosive concentrations of hydrogen can accumulate, and mitigation of risk requires a control function associated with detection that can trigger alarms or actuate devices to prevent hydrogen concentrations from reaching the explosive limit. The approach at NREL to meet the needs for hydrogen detection that are anticipated in the transportation sector uses thin films to indicate the presence of hydrogen. The thin films react with hydrogen to produce a change in optical properties that can be sensed with a light beam propagating along a fiber-optic element. Sensitivity of the device is 200 ppm hydrogen in air, with response times less than one second. The sensor response is unique to hydrogen. It is inherently safe, in that no wires are used that could provide an ignition source in a monitored space. Sensor films can be deposited inexpensively on the end of commercial fiber optic cables, either glass or polymer. They are lightweight and resistant to interference from electric and magnetic fields. Arrays of sensors can be operated from a single detection and control point. Primary challenges involve stabilizing the response in real environments, where pollutants and contamination of the thin film surface interfere with response, and extending the lifetime of the sensor to periods of interest in the transportation sector.

  8. Commercialization Issues For Catheter-Based Electrochemical Sensors

    NASA Astrophysics Data System (ADS)

    Nikolchev, Julian; Gaisford, Scott

    1989-08-01

    The need for continuous monitoring of key clinical parameters in hospitals is well recognized. Figure 1 shows typical time constants for blood gases, ions and enzymes in response to acute ventilatory changes and interventions. Although it can be seen that relatively low rates of data collection are necessary for many medical measurements, it is also clear that intermittent measurement of P02, PCO2 and pH are not sufficient to provide safe and effective management of the patient. Very frequent or continuous monitoring is often essential. This figure also shows why the emphasis of a large number of research efforts in this country and in Europe and Japan have as their goal the development of continuous blood gas sensors, i.e., sensors that continuously monitor blood pH, partial pressure of oxygen and partial pressure of carbon dioxide. These are three (3) of the most frequent parameters measured in hospitals and the ones having the shortest time constant. Considering that in the United States alone close to 25 million blood gas samples per year are taken from patients, the potential market for continuous monitoring sensors is enormous. The emergence of microelectronics and microfabrication technologies over the past 30 years are now pointing to a possible resolution of the well recognized need for real time monitoring of critically ill patients through catheter-based sensors. Although physicians will always prefer non-invasive monitoring techniques, there are a number of parameters that presently can only be monitored by invasive method. The emerging ability to miniaturize chemical sensors using silicon microfabrication or fiber-optic techniques offer an excellent opportunity to solve this need. In fact, the development of in vivo biomedical sensors with satisfactory performance characteristics has long been considered the ultimate application of these emerging technologies.

  9. Functional nucleic-acid-based sensors for environmental monitoring.

    PubMed

    Sett, Arghya; Das, Suradip; Bora, Utpal

    2014-10-01

    Efforts to replace conventional chromatographic methods for environmental monitoring with cheaper and easy to use biosensors for precise detection and estimation of hazardous environmental toxicants, water or air borne pathogens as well as various other chemicals and biologics are gaining momentum. Out of the various types of biosensors classified according to their bio-recognition principle, nucleic-acid-based sensors have shown high potential in terms of cost, sensitivity, and specificity. The discovery of catalytic activities of RNA (ribozymes) and DNA (DNAzymes) which could be triggered by divalent metallic ions paved the way for their extensive use in detection of heavy metal contaminants in environment. This was followed with the invention of small oligonucleotide sequences called aptamers which can fold into specific 3D conformation under suitable conditions after binding to target molecules. Due to their high affinity, specificity, reusability, stability, and non-immunogenicity to vast array of targets like small and macromolecules from organic, inorganic, and biological origin, they can often be exploited as sensors in industrial waste management, pollution control, and environmental toxicology. Further, rational combination of the catalytic activity of DNAzymes and RNAzymes along with the sequence-specific binding ability of aptamers have given rise to the most advanced form of functional nucleic-acid-based sensors called aptazymes. Functional nucleic-acid-based sensors (FNASs) can be conjugated with fluorescent molecules, metallic nanoparticles, or quantum dots to aid in rapid detection of a variety of target molecules by target-induced structure switch (TISS) mode. Although intensive research is being carried out for further improvements of FNAs as sensors, challenges remain in integrating such bio-recognition element with advanced transduction platform to enable its use as a networked analytical system for tailor made analysis of environmental

  10. Monitoring and Control Interface Based on Virtual Sensors

    PubMed Central

    Escobar, Ricardo F.; Adam-Medina, Manuel; García-Beltrán, Carlos D.; Olivares-Peregrino, Víctor H.; Juárez-Romero, David; Guerrero-Ramírez, Gerardo V.

    2014-01-01

    In this article, a toolbox based on a monitoring and control interface (MCI) is presented and applied in a heat exchanger. The MCI was programed in order to realize sensor fault detection and isolation and fault tolerance using virtual sensors. The virtual sensors were designed from model-based high-gain observers. To develop the control task, different kinds of control laws were included in the monitoring and control interface. These control laws are PID, MPC and a non-linear model-based control law. The MCI helps to maintain the heat exchanger under operation, even if a temperature outlet sensor fault occurs; in the case of outlet temperature sensor failure, the MCI will display an alarm. The monitoring and control interface is used as a practical tool to support electronic engineering students with heat transfer and control concepts to be applied in a double-pipe heat exchanger pilot plant. The method aims to teach the students through the observation and manipulation of the main variables of the process and by the interaction with the monitoring and control interface (MCI) developed in LabVIEW©. The MCI provides the electronic engineering students with the knowledge of heat exchanger behavior, since the interface is provided with a thermodynamic model that approximates the temperatures and the physical properties of the fluid (density and heat capacity). An advantage of the interface is the easy manipulation of the actuator for an automatic or manual operation. Another advantage of the monitoring and control interface is that all algorithms can be manipulated and modified by the users. PMID:25365462

  11. Monitoring and control interface based on virtual sensors.

    PubMed

    Escobar, Ricardo F; Adam-Medina, Manuel; García-Beltrán, Carlos D; Olivares-Peregrino, Víctor H; Juárez-Romero, David; Guerrero-Ramírez, Gerardo V

    2014-01-01

    In this article, a toolbox based on a monitoring and control interface (MCI) is presented and applied in a heat exchanger. The MCI was programed in order to realize sensor fault detection and isolation and fault tolerance using virtual sensors. The virtual sensors were designed from model-based high-gain observers. To develop the control task, different kinds of control laws were included in the monitoring and control interface. These control laws are PID, MPC and a non-linear model-based control law. The MCI helps to maintain the heat exchanger under operation, even if a temperature outlet sensor fault occurs; in the case of outlet temperature sensor failure, the MCI will display an alarm. The monitoring and control interface is used as a practical tool to support electronic engineering students with heat transfer and control concepts to be applied in a double-pipe heat exchanger pilot plant. The method aims to teach the students through the observation and manipulation of the main variables of the process and by the interaction with the monitoring and control interface (MCI) developed in LabVIEW©. The MCI provides the electronic engineering students with the knowledge of heat exchanger behavior, since the interface is provided with a thermodynamic model that approximates the temperatures and the physical properties of the fluid (density and heat capacity). An advantage of the interface is the easy manipulation of the actuator for an automatic or manual operation. Another advantage of the monitoring and control interface is that all algorithms can be manipulated and modified by the users. PMID:25365462

  12. Mobile phone based electrochemiluminescence detection in paper-based microfluidic sensors.

    PubMed

    Delaney, Jacqui L; Hogan, Conor F

    2015-01-01

    The development of simple, inexpensive paper-based sensors for medical diagnostics and other applications is now an important emerging area in the field of biosensors; however, the electronic instrument or reader used to interrogate such sensors adds significantly to the cost of the analysis. In this chapter we describe the design and construction of novel, low-cost disposable electrochemiluminescent (ECL) sensors based on screen printed carbon electrodes and paper-based microfluidics. Moreover, a method to interrogate these sensors using only a mobile phone is articulated. This is realized by exploiting the audio output of the device to achieve electrochemical control, while using the camera to detect the resulting light emitted during the ECL reaction. The combination of cell phone technology with low-cost paper microfluidic sensors dramatically reduces the cost of sensing and has the potential to enhance health-care outcomes by exploiting the functionality, connectivity, and close to worldwide penetration of mobile phone technology. PMID:25626546

  13. Flat Panel Space Based Space Surveillance Sensor

    NASA Astrophysics Data System (ADS)

    Kendrick, R.; Duncan, A.; Wilm, J.; Thurman, S. T.; Stubbs, D. M.; Ogden, C.

    2013-09-01

    Traditional electro-optical (EO) imaging payloads consist of an optical telescope to collect the light from the object scene and map the photons to an image plane to be digitized by a focal plane detector array. The size, weight, and power (SWaP) for the traditional EO imager is dominated by the optical telescope, driven primarily by the large optics, large stiff structures, and the thermal control needed to maintain precision free-space optical alignments. We propose a non-traditional Segmented Planar Imaging Detector for EO Reconnaissance (SPIDER) imager concept that is designed to substantially reduce SWaP, by at least an order of magnitude. SPIDER maximizes performance by providing a larger effective diameter (resolution) while minimizing mass and cost. SPIDER replaces the traditional optical telescope and digital focal plane detector array with a densely packed interferometer array based on emerging photonic integrated circuit (PIC) technologies. Lenslets couple light from the object into a set of waveguides on a PIC. Light from each lenslet is distributed among different waveguides by both field angle and optical frequency, and the lenslets are paired up to form unique interferometer baselines by combining light from different waveguides. The complex spatial coherence of the object (for each field angle, frequency, and baseline) is measured with a balanced four quadrature detection scheme. By the Van-Cittert Zernike Theorem, each measurement corresponds to a unique Fourier component of the incoherent object intensity distribution. Finally, an image reconstruction algorithm is used to invert all the data and form an image. Our approach replaces the large optics and structures required by a conventional telescope with PICs that are accommodated by standard lithographic fabrication techniques (e.g., CMOS fabrication). The standard EO payload integration and test process which involves precision alignment and test of optical components to form a diffraction

  14. Wheel-Based Ice Sensors for Road Vehicles

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey; Fink, Patrick W.; Ngo, Phong H.; Carl, James R.

    2011-01-01

    Wheel-based sensors for detection of ice on roads and approximate measurement of the thickness of the ice are under development. These sensors could be used to alert drivers to hazardous local icing conditions in real time. In addition, local ice-thickness measurements by these sensors could serve as guidance for the minimum amount of sand and salt required to be dispensed locally onto road surfaces to ensure safety, thereby helping road crews to utilize their total supplies of sand and salt more efficiently. Like some aircraft wing-surface ice sensors described in a number of previous NASA Tech Briefs articles, the wheelbased ice sensors are based, variously, on measurements of changes in capacitance and/or in radio-frequency impedance as affected by ice on surfaces. In the case of ice on road surfaces, the measurable changes in capacitance and/or impedance are attributable to differences among the electric permittivities of air, ice, water, concrete, and soil. In addition, a related phenomenon that can be useful for distinguishing between ice and water is a specific transition in the permittivity of ice at a temperature- dependent frequency. This feature also provides a continuous calibration of the sensor to allow for changing road conditions. Several configurations of wheel-based ice sensors are under consideration. For example, in a simple two-electrode capacitor configuration, one of the electrodes would be a circumferential electrode within a tire, and the ground would be used as the second electrode. Optionally, the steel belts that are already standard parts of many tires could be used as the circumferential electrodes. In another example (see figure), multiple electrodes would be embedded in rubber between the steel belt and the outer tire surface. These electrodes would be excited in alternating polarities at one or more suitable audio or radio frequencies to provide nearly continuous monitoring of the road surface under the tire. In still another

  15. Home-based alcohol prevention program for parents and children: A randomized controlled trial.

    PubMed

    Mares, S H W; Lichtwarck-Aschoff, A; Verdurmen, J; Schulten, I; Engels, R C M E

    2016-07-01

    Objective To evaluate the effectiveness of a home-based alcohol prevention program to delay initiation of alcohol use in children. Methods In 2011, a total of 1349 sixth-grade children (M=12.15, SD=0.47) and their mothers who could read and write Dutch were recruited from primary schools in the northern part of the Netherlands. They participated in a cluster randomized controlled trial with two conditions; (1) intervention group (5 modules which families received by mail every 4weeks over 5months), (2) control group (a factsheet information brochure). An independent statistician allocated the schools to the conditions (allocation ratio (1:1)). Participants and data-analyst were blind to randomization. The primary outcome was alcohol initiation. Results Of the participants, 680 were randomized to the intervention and 669 to the control condition. In the intervention condition (N=540) 5.4% of the children drank alcohol compared to 7.1% in the control condition (N=601). The difference was not significant (OR=.99, 95% CI=.96-1.02, p=52). Conclusion The present study showed no effects of 'In control: No alcohol!' on alcohol initiation. A critical evaluation of program design and content, and future studies in different target groups, are suggested. The trial is registered at trialregister.nl, number NTR2474. PMID:27143498

  16. Reducing youth access to alcohol: findings from a community-based randomized trial.

    PubMed

    Flewelling, Robert L; Grube, Joel W; Paschall, M J; Biglan, Anthony; Kraft, Anne; Black, Carol; Hanley, Sean M; Ringwalt, Christopher; Wiesen, Chris; Ruscoe, Jeff

    2013-03-01

    Underage drinking continues to be an important public health problem and a challenge to the substance abuse prevention field. Community-based interventions designed to more rigorously control underage access to alcohol through retailer education and greater enforcement of underage drinking laws have been advocated as potentially effective strategies to help address this problem, but studies designed to evaluate such interventions are sparse. To address this issue we conducted a randomized trial involving 36 communities to test the combined effectiveness of five interrelated intervention components designed to reduce underage access to alcohol. The intervention was found to be effective in reducing the likelihood that retail clerks would sell alcohol to underage-looking buyers, but did not reduce underage drinking or the perceived availability of alcohol among high school students. Post hoc analyses, however, revealed significant associations between the level of underage drinking law enforcement in the intervention communities and reductions in both 30-day use of alcohol and binge drinking. The findings highlight the difficulty in reducing youth drinking even when efforts to curtail retail access are successful. Study findings also suggest that high intensity implementation of underage drinking law enforcement can reduce underage drinking. Any such effects of enhanced enforcement on underage drinking appear to be more directly attributable to an increase in perceived likelihood of enforcement and the resultant perceived inconveniences and/or sanctions to potential drinkers, than to a reduction in access to alcohol per se. PMID:22688848

  17. Reducing Youth Access to Alcohol: Findings from a Community-Based Randomized Trial*

    PubMed Central

    Flewelling, Robert L.; Grube, Joel W.; Paschall, M.J.; Biglan, Anthony; Kraft, Anne; Black, Carol; Hanley, Sean; Ringwalt, Christopher; Wiesen, Chris; Ruscoe, Jeff

    2012-01-01

    Underage drinking continues to be an important public health problem and a challenge to the substance abuse prevention field. Community-based interventions designed to more rigorously control underage access to alcohol through retailer education and greater enforcement of underage drinking laws have been advocated as potentially effective strategies to help address this problem, but studies designed to evaluate such interventions are sparse. To address this issue we conducted a randomized trial involving 36 communities to test the combined effectiveness of five interrelated intervention components designed to reduce underage access to alcohol. The intervention was found to be effective in reducing the likelihood that retail clerks would sell alcohol to underage-looking buyers, but did not reduce underage drinking or the perceived availability of alcohol among high school students. Post hoc analyses, however, revealed significant associations between the level of underage drinking law enforcement in the intervention communities and reductions in both 30-day use of alcohol and binge drinking. The findings highlight the difficulty in reducing youth drinking even when efforts to curtail retail access are successful. Study findings also suggest that high intensity implementation of underage drinking law enforcement can reduce underage drinking. Any such effects of enhanced enforcement on underage drinking appear to be more directly attributable to an increase in perceived likelihood of enforcement and the resultant perceived inconveniences and/or sanctions to potential drinkers, than to a reduction in access to alcohol per se. PMID:22688848

  18. Oral cancer: the association between nation-based alcohol-drinking profiles and oral cancer mortality.

    PubMed

    Petti, Stefano; Scully, Crispian

    2005-09-01

    The unclear association between different nation-based alcohol-drinking profiles and oral cancer mortality was investigated using, as observational units, 20 countries from Europe, Northern America, Far Eastern Asia, with cross-nationally comparable data. Stepwise multiple regression analyses were run with male age-standardised, mortality rate (ASMR) as explanatory variable and annual adult alcohol consumption, adult smoking prevalence, life expectancy, as explanatory. Large between-country differences in ASMR (range, 0.88-6.87 per 100,000) were found, but the mean value was similar to the global estimate (3.31 vs. 3.09 per 100,000). Differences in alcohol consumption (2.06-21.03 annual litres per capita) and in distribution between beverages were reported. Wine was the most prevalent alcoholic beverage in 45% of cases. Significant increases in ASMR for every litre of pure ethanol (0.15 per 100,000; 95 CI, 0.01-0.29) and spirits (0.26 per 100,000; 95 CI, 0.03-0.49), non-significant effects for beer and wine were estimated. The impact of alcohol on oral cancer deaths would be higher than expected and the drinking profile could affect cancer mortality, probably because of the different drinking pattern of spirit drinkers, usually consuming huge alcohol quantities on single occasions, and the different concentrations of ethanol and cancer-preventing compounds such as polyphenols, in the various beverages. PMID:15979385

  19. Feedback from recently returned veterans on an anonymous web-based brief alcohol intervention

    PubMed Central

    2012-01-01

    Background Veterans of Operation Enduring Freedom and Operation Iraqi Freedom (OEF/OIF) are at increased risk for alcohol misuse, and innovative methods are needed to improve their access to alcohol screening and brief interventions (SBI). This study adapted an electronic SBI (e-SBI) website shown to be efficacious in college students for OEF/OIF veterans and reported findings from interviews with OEF/OIF veterans about their impressions of the e-SBI. Methods Outpatient veterans of OEF/OIF who drank ≥3 days in the past week were recruited from a US Department of Veterans Affairs (VA) Deployment Health Clinic waiting room. Veterans privately pretested the anonymous e-SBI then completed individual semistructured audio-recorded interviews. Their responses were analyzed using template analysis to explore domains identified a priori as well as emergent domains. Results During interviews, all nine OEF/OIF veterans (1 woman and 8 men) indicated they had received feedback for risky alcohol consumption. Participants generally liked the standard-drinks image, alcohol-related caloric and monetary feedback, and the website’s brevity and anonymity (a priori domains). They also experienced challenges with portions of the e-SBI assessment and viewed feedback regarding alcohol risk and normative drinking as problematic, but described potential benefits derived from the e-SBI (emergent domains). The most appealing e-SBIs would ensure anonymity and provide personalized transparent feedback about alcohol-related risk, consideration of the context for drinking, strategies to reduce drinking, and additional resources for veterans with more severe alcohol misuse. Conclusions Results of this qualitative exploratory study suggest e-SBI may be an acceptable strategy for increasing OEF/OIF veteran access to evidenced-based alcohol SBI. PMID:23186354

  20. Video Based Sensor for Tracking 3-Dimensional Targets

    NASA Technical Reports Server (NTRS)

    Howard, R. T.; Book, Michael L.; Bryan, Thomas C.

    2000-01-01

    Video-Based Sensor for Tracking 3-Dimensional Targets The National Aeronautics and Space Administration's (NASAs) Marshall Space Flight Center (MSFC) has been developing and testing video-based sensors for automated spacecraft guidance for several years, and the next generation of video sensor will have tracking rates up to 100 Hz and will be able to track multiple reflectors and targets. The Video Guidance Sensor (VGS) developed over the past several years has performed well in testing and met the objective of being used as the terminal guidance sensor for an automated rendezvous and capture system. The first VGS was successfully tested in closed-loop 3-degree-of-freedom (3- DOF) tests in 1989 and then in 6-DOF open-loop tests in 1992 and closed-loop tests in 1993-4. Development and testing continued, and in 1995 approval was given to test the VGS in an experiment on the Space Shuttle. The VGS flew in 1997 and in 1998, performing well for both flights. During the development and testing before, during, and after the flight experiments, numerous areas for improvement were found. The VGS was developed with a sensor head and an electronics box, connected by cables. The VGS was used in conjunction with a target that had wavelength-filtered retro-reflectors in a specific pattern, The sensor head contained the laser diodes, video camera, and heaters and coolers. The electronics box contained a frame grabber, image processor, the electronics to control the components in the sensor head, the communications electronics, and the power supply. The system works by sequentially firing two different wavelengths of laser diodes at the target and processing the two images. Since the target only reflects one wavelength, it shows up well in one image and not at all in the other. Because the target's dimensions are known, the relative positions and attitudes of the target and the sensor can be computed from the spots reflected from the target. The system was designed to work from I

  1. Using Custom Fiber Bragg Grating-Based Sensors to Monitor Artificial Landslides.

    PubMed

    Zhang, Qinghua; Wang, Yuan; Sun, Yangyang; Gao, Lei; Zhang, Zhenglin; Zhang, Wenyuan; Zhao, Pengchong; Yue, Yin

    2016-01-01

    Four custom fiber Bragg grating (FBG)-based sensors are developed to monitor an artificial landslide located in Nanjing, China. The sensors are composed of a rod and two FBGs. Based on the strength of the rods, two sensors are referred to as "hard sensors" (Sensor 1 and Sensor 2), the other two are referred to as "soft sensors" (Sensor 3 and Sensor 4). The two FBGs are fixed on each sensor rod at distances of 50 cm and 100 cm from the top of the rod (an upper FBG and a lower FBG). In the experiment presented in this paper, the sensors are installed on a slope on which an artificial landslide is generated through both machine-based and manual excavation. The fiber sensing system consists of the four custom FBG-based sensors, optical fiber, a static fiber grating demodulation instrument (SM125), and a PC with the necessary software. Experimental data was collected in the presence of an artificial landslide, and the results show that the lower FBGs are more sensitive than the upper FBGs for all four of the custom sensors. It was also found that Sensor 2 and Sensor 4 are more capable of monitoring small-scale landslides than Sensor 1 and Sensor 3, and this is mainly due to their placement location with respect to the landslide. The stronger rods used in the hard sensors make them more adaptable to the harsh environments of large landslides. Thus, hard sensors should be fixed near the landslide, while soft sensors should be placed farther away from the landslide. In addition, a clear tendency of strain variation can be detected by the soft sensors, which can be used to predict landslides and raise a hazard alarm. PMID:27598163

  2. Novel optical fiber ultrasonic sensor based on fiber laser

    NASA Astrophysics Data System (ADS)

    Wu, Qi; Okabe, Yoji; Sun, Junqiang

    2014-03-01

    Researching high-sensitivity flexible ultrasonic sensor is important in the field of structural health monitoring (SHM). In this research, a novel ultrasonic sensor based on fiber ring laser with an in-built phase shifted fiber Bragg grating (PSFBG) is proposed and demonstrated. The first function of the PS-FBG is to determine the wavelength of the laser. Thus, this sensing system is robust to temperature change and quasi-static strain change because the PS-FBG is always illuminated. The other function of the PS-FBG is a sensor with ultra-steep slope and short effective grating length. It is beneficial for achievement of high-sensitivity and broad-bandwidth ultrasonic detection. The experimental evaluated sensitivity was 58.5+/-3 dB, which is 7.5 dB higher than traditional PZT sensor. This may be the highest sensitivity obtained by optical fiber sensing system. Because of the advantages including robustness, simple structure and low cost in addition to the high sensitivity and broad bandwidth, this sensing system has potential practical applications in ultrasonic SHM.

  3. Peristaltic pump-based low range pressure sensor calibration system

    SciTech Connect

    Vinayakumar, K. B.; Naveen Kumar, G.; Rajanna, K. E-mail: krajanna2011@gmail.com; Nayak, M. M.; Dinesh, N. S.

    2015-11-15

    Peristaltic pumps were normally used to pump liquids in several chemical and biological applications. In the present study, a peristaltic pump was used to pressurize the chamber (positive as well negative pressures) using atmospheric air. In the present paper, we discuss the development and performance study of an automatic pressurization system to calibrate low range (millibar) pressure sensors. The system includes a peristaltic pump, calibrated pressure sensor (master sensor), pressure chamber, and the control electronics. An in-house developed peristaltic pump was used to pressurize the chamber. A closed loop control system has been developed to detect and adjust the pressure leaks in the chamber. The complete system has been integrated into a portable product. The system performance has been studied for a step response and steady state errors. The system is portable, free from oil contaminants, and consumes less power compared to existing pressure calibration systems. The veracity of the system was verified by calibrating an unknown diaphragm based pressure sensor and the results obtained were satisfactory.

  4. Peristaltic pump-based low range pressure sensor calibration system

    NASA Astrophysics Data System (ADS)

    Vinayakumar, K. B.; Naveen Kumar, G.; Nayak, M. M.; Dinesh, N. S.; Rajanna, K.

    2015-11-01

    Peristaltic pumps were normally used to pump liquids in several chemical and biological applications. In the present study, a peristaltic pump was used to pressurize the chamber (positive as well negative pressures) using atmospheric air. In the present paper, we discuss the development and performance study of an automatic pressurization system to calibrate low range (millibar) pressure sensors. The system includes a peristaltic pump, calibrated pressure sensor (master sensor), pressure chamber, and the control electronics. An in-house developed peristaltic pump was used to pressurize the chamber. A closed loop control system has been developed to detect and adjust the pressure leaks in the chamber. The complete system has been integrated into a portable product. The system performance has been studied for a step response and steady state errors. The system is portable, free from oil contaminants, and consumes less power compared to existing pressure calibration systems. The veracity of the system was verified by calibrating an unknown diaphragm based pressure sensor and the results obtained were satisfactory.

  5. An Electrochemical Glucose Sensor Based on Zinc Oxide Nanorods.

    PubMed

    Marie, Mohammed; Mandal, Sanghamitra; Manasreh, Omar

    2015-01-01

    A glucose electrochemical sensor based on zinc oxide (ZnO) nanorods was investigated. The hydrothermal sol-gel growth method was utilized to grow ZnO nanorods on indium tin oxide-coated glass substrates. The total active area of the working electrode was 0.3 × 0.3 cm2 where titanium metal was deposited to enhance the contact. Well aligned hexagonal structured ZnO nanorods with a diameter from 68 to 116 nm were obtained. The excitonic peak obtained from the absorbance spectroscopy was observed at ~370 nm. The dominant peak of Raman spectroscopy measurement was at 440 cm(-1), matching with the lattice vibration of ZnO. The uniform distribution of the GOx and Nafion membrane that has been done using spin coating technique at 4000 rotations per minute helps in enhancing the ion exchange and increasing the sensitivity of the fabricated electrochemical sensor. The amperometric response of the fabricated electrochemical sensor was 3 s. The obtained sensitivity of the fabricated ZnO electrochemical sensor was 10.911 mA/mM·cm2 and the lower limit of detection was 0.22 µM. PMID:26263988

  6. Peristaltic pump-based low range pressure sensor calibration system.

    PubMed

    Vinayakumar, K B; Naveen Kumar, G; Nayak, M M; Dinesh, N S; Rajanna, K

    2015-11-01

    Peristaltic pumps were normally used to pump liquids in several chemical and biological applications. In the present study, a peristaltic pump was used to pressurize the chamber (positive as well negative pressures) using atmospheric air. In the present paper, we discuss the development and performance study of an automatic pressurization system to calibrate low range (millibar) pressure sensors. The system includes a peristaltic pump, calibrated pressure sensor (master sensor), pressure chamber, and the control electronics. An in-house developed peristaltic pump was used to pressurize the chamber. A closed loop control system has been developed to detect and adjust the pressure leaks in the chamber. The complete system has been integrated into a portable product. The system performance has been studied for a step response and steady state errors. The system is portable, free from oil contaminants, and consumes less power compared to existing pressure calibration systems. The veracity of the system was verified by calibrating an unknown diaphragm based pressure sensor and the results obtained were satisfactory. PMID:26628178

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

    NASA Astrophysics Data System (ADS)

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

    2012-05-01

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

  8. Compact hyperspectral image sensor based on a novel hyperspectral encoder

    NASA Astrophysics Data System (ADS)

    Hegyi, Alex N.; Martini, Joerg

    2015-06-01

    A novel hyperspectral imaging sensor is demonstrated that can enable breakthrough applications of hyperspectral imaging in domains not previously accessible. Our technology consists of a planar hyperspectral encoder combined with a traditional monochrome image sensor. The encoder adds negligibly to the sensor's overall size, weight, power requirement, and cost (SWaP-C); therefore, the new imager can be incorporated wherever image sensors are currently used, such as in cell phones and other consumer electronics. In analogy to Fourier spectroscopy, the technique maintains a high optical throughput because narrow-band spectral filters are unnecessary. Unlike conventional Fourier techniques that rely on Michelson interferometry, our hyperspectral encoder is robust to vibration and amenable to planar integration. The device can be viewed within a computational optics paradigm: the hardware is uncomplicated and serves to increase the information content of the acquired data, and the complexity of the system, that is, the decoding of the spectral information, is shifted to computation. Consequently, system tradeoffs, for example, between spectral resolution and imaging speed or spatial resolution, are selectable in software. Our prototype demonstration of the hyperspectral imager is based on a commercially-available silicon CCD. The prototype encoder was inserted within the camera's ~1 cu. in. housing. The prototype can image about 49 independent spectral bands distributed from 350 nm to 1250 nm, but the technology may be extendable over a wavelength range from ~300 nm to ~10 microns, with suitable choice of detector.

  9. Optical fiber sensor for nitroaromatic explosives based on fluorescence quenching

    NASA Astrophysics Data System (ADS)

    Chu, Fenghong

    2010-10-01

    The detection of explosives and related compounds is important in both forensic and environmental applications. In this paper, we report on the preparation of novel plastic optical fiber explosive sensor based on fluorescence quenching. A low priced LED light source and PIN detector were used in this sensor system, a U-shaped plastic optical fiber with high sensitivity act as sensor head. We use amplifying fluorescent polymers (AFP) MEH-PPV as fluorescence indictor. MEHPPV was dip coated on to the surface of the U-shaped plastic optical fiber. For the first time as far as we know we detected the fluorescence lifetime by the phase-fluorometry method to measure the concentration of TNT, which has a merit of immunity to fluctuation of the light source and is more reliable than measuring intensity alone. In the experimental set-up the phase shift between excitation light and fluorescence is calculated by correlation method. Two degree phase difference was measured when the sensor head was exposed to TNT vapor and air in primary experiments.

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

    PubMed

    Zhang, Congcong; Chen, Penglei; Hu, Wenping

    2015-04-21

    Organic field-effect transistors (OFETs) are one of the key components of modern organic electronics. While the past several decades have witnessed huge successes in high-performance OFETs, their sophisticated functionalization with regard to the responses towards external stimulations has also aroused increasing attention and become an important field of general concern. This is promoted by the inherent merits of organic semiconductors, including considerable variety in molecular design, low cost, light weight, mechanical flexibility, and solution processability, as well as by the intrinsic advantages of OFETs including multiparameter accessibility and ease of large-scale manufacturing, which provide OFETs with great potential as portable yet reliable sensors offering high sensitivity, selectivity, and expeditious responses. With special emphases on the works achieved since 2009, this tutorial review focuses on OFET-based gas sensors. The working principles of this type of gas sensors are discussed in detail, the state-of-the-art protocols developed for high-performance gas sensing are highlighted, and the advanced gas discrimination systems in terms of sensory arrays of OFETs are also introduced. This tutorial review intends to provide readers with a deep understanding for the future design of high-quality OFET gas sensors for potential uses. PMID:25727357

  11. A batteryless temperature sensor based on high temperature sensitive material

    NASA Astrophysics Data System (ADS)

    Bakkali, Asma; Pelegri-Sebastia, José; Laghmich, Youssef; Lyhyaoui, Abdelouahid

    2016-05-01

    The major challenge in wireless sensor networks is the reduction of energy consumption. Passive wireless sensor network is an attractive solution for measuring physical parameters in harsh environment for large range of applications requiring sensing devices with low cost of fabrication, small size and long term measurement stability. Batteryless temperature sensing techniques are an active research field. The approach developed in our work holds a promising future for temperature sensor applications in order to successfully reduce the energy consumption. The temperature sensor presented in this paper is based on the electromagnetic transduction principle using the integration of the high temperature sensitive material into a passive structure. Variation in temperature makes the dielectric constant of this material changing, and such modification induces variation in the resonant frequencies of high-Q whispering-gallery modes (WGM) in the millimeter-wave frequency range. Following the results achieved, the proposed device shows a linear response to the increasing temperature and these variations can be remotely detected from a radar interrogation. Contribution to the topical issue "Materials for Energy Harvesting, Conversion and Storage (ICOME 2015) - Elected submissions", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

  12. A Fiber Bragg Grating Sensing Based Triaxial Vibration Sensor

    PubMed Central

    Li, Tianliang; Tan, Yuegang; Liu, Yi; Qu, Yongzhi; Liu, Mingyao; Zhou, Zude

    2015-01-01

    A fiber Bragg grating (FBG) sensing based triaxial vibration sensor has been presented in this paper. The optical fiber is directly employed as elastomer, and the triaxial vibration of a measured body can be obtained by two pairs of FBGs. A model of a triaxial vibration sensor as well as decoupling principles of triaxial vibration and experimental analyses are proposed. Experimental results show that: sensitivities of 86.9 pm/g, 971.8 pm/g and 154.7 pm/g for each orthogonal sensitive direction with linearity are separately 3.64%, 1.50% and 3.01%. The flat frequency ranges reside in 20–200 Hz, 3–20 Hz and 4–50 Hz, respectively; in addition, the resonant frequencies are separately 700 Hz, 40 Hz and 110 Hz in the x/y/z direction. When the sensor is excited in a single direction vibration, the outputs of sensor in the other two directions are consistent with the outputs in the non-working state. Therefore, it is effectively demonstrated that it can be used for three-dimensional vibration measurement. PMID:26393616

  13. BIOME: An Ecosystem Remote Sensor Based on Imaging Interferometry

    NASA Technical Reports Server (NTRS)

    Peterson, David L.; Hammer, Philip; Smith, William H.; Lawless, James G. (Technical Monitor)

    1994-01-01

    Until recent times, optical remote sensing of ecosystem properties from space has been limited to broad band multispectral scanners such as Landsat and AVHRR. While these sensor data can be used to derive important information about ecosystem parameters, they are very limited for measuring key biogeochemical cycling parameters such as the chemical content of plant canopies. Such parameters, for example the lignin and nitrogen contents, are potentially amenable to measurements by very high spectral resolution instruments using a spectroscopic approach. Airborne sensors based on grating imaging spectrometers gave the first promise of such potential but the recent decision not to deploy the space version has left the community without many alternatives. In the past few years, advancements in high performance deep well digital sensor arrays coupled with a patented design for a two-beam interferometer has produced an entirely new design for acquiring imaging spectroscopic data at the signal to noise levels necessary for quantitatively estimating chemical composition (1000:1 at 2 microns). This design has been assembled as a laboratory instrument and the principles demonstrated for acquiring remote scenes. An airborne instrument is in production and spaceborne sensors being proposed. The instrument is extremely promising because of its low cost, lower power requirements, very low weight, simplicity (no moving parts), and high performance. For these reasons, we have called it the first instrument optimized for ecosystem studies as part of a Biological Imaging and Observation Mission to Earth (BIOME).

  14. Bio-chemical sensor based on imperfected plastic optical fiber

    NASA Astrophysics Data System (ADS)

    Babchenko, Anatoly; Chernyak, Valeri; Maryles, Jonathan

    2007-05-01

    In this paper we report results for an intrinsic evanescent field sensor based on not-regular plastic optical fiber with polymer film containing Malachite Green MG +([PhC(C 6H 4NMe II) 3] +) as an absorption reagent, which coats the fiber's imperfected area. A theoretical model was developed which shows that changes of light in such structure result from the attenuation of light in the strait and bent imperfected fiber. In this model, the imperfected area with malachite green polymer film is replaced by a uniform layer with a complex refractive index. The changes in color and absorption characteristics of the polymer film depend on the acidic and basic environmental properties in the sensing area. Additional increase of the evanescent field interaction can be achieved by decrease the bending radius of the fiber with the coated imperfection area at the middle of the bent fiber. An imperfected plastic optical fiber with Malachite Green coating has been presented for the detection of ammonia vapor. The initial results show that depending on the sensing application demands, it is possible to design a high sensitive sensor with a relatively long response time, while when the demands require fast response times the sensor with less sensitivity can be used. In addition, the sensors' sensitivity can be calibrated in real-time by changing the bending radius.

  15. A Fiber Bragg Grating Sensing Based Triaxial Vibration Sensor.

    PubMed

    Li, Tianliang; Tan, Yuegang; Liu, Yi; Qu, Yongzhi; Liu, Mingyao; Zhou, Zude

    2015-01-01

    A fiber Bragg grating (FBG) sensing based triaxial vibration sensor has been presented in this paper. The optical fiber is directly employed as elastomer, and the triaxial vibration of a measured body can be obtained by two pairs of FBGs. A model of a triaxial vibration sensor as well as decoupling principles of triaxial vibration and experimental analyses are proposed. Experimental results show that: sensitivities of 86.9 pm/g, 971.8 pm/g and 154.7 pm/g for each orthogonal sensitive direction with linearity are separately 3.64%, 1.50% and 3.01%. The flat frequency ranges reside in 20-200 Hz, 3-20 Hz and 4-50 Hz, respectively; in addition, the resonant frequencies are separately 700 Hz, 40 Hz and 110 Hz in the x/y/z direction. When the sensor is excited in a single direction vibration, the outputs of sensor in the other two directions are consistent with the outputs in the non-working state. Therefore, it is effectively demonstrated that it can be used for three-dimensional vibration measurement. PMID:26393616

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

    PubMed

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

    2012-05-01

    Fabrication and testing of micro-reactors for the characterization of nanosensors is presented in this work. The reactors have a small volume (100 μl) and are equipped with gas input/output channels. They were machined from a single piece of kovar in order to avoid leaks in the system due to additional welding. The contact pins were electrically insulated from the body of the reactor using a borosilicate sealing glass and the reactor was hermetically sealed using a lid and an elastomeric o-ring. One of the advantages of the reactor lies in its simple assembly and ease of use with any vacuum/gas system, allowing the connection of more than one device. Moreover, the lid can be modified in order to fit a window for in situ optical characterization. In order to prove its versatility, carbon nanotube-based sensors were tested using this micro-reactor. The devices were fabricated by depositing carbon nanotubes over 1 μm thick gold electrodes patterned onto Si/SiO(2) substrates. The sensors were tested using oxygen and nitrogen atmospheres, in the pressure range between 10(-5) and 10(-1) mbar. The small chamber volume allowed the measurement of fast sensor characteristic times, with the sensors showing good sensitivity towards gas and pressure as well as high reproducibility. PMID:22667654

  17. ZnO Coated Nanospring-Based Gas Sensors

    NASA Astrophysics Data System (ADS)

    Bakharev, Pavel Viktorovich

    . The experimental and computational analyses of the sensing properties of the 3-D (nanospring-based) and flat thin films structures show that the complexity and periodic boundary conditions of the nanospring-based devices result in a lower detection limit, while flat thin films exhibit higher sensitivity to small analyte concentration fluctuations. Our analysis shows that the productive approach to fabrication of integrated sensors (electronic noses) is to use both the structures (3D and flat geometries) as the receptors for a prompt and reliable detection and recognition of the target chemical compounds. Analog lock-in amplifier (LIA) AC measurements of the electrical response have been performed to significantly improve the signal-to-noise ratio (SNR) and reduce the detection limit of the single ZnO coated nanospring chemiresistor from the ppm to the ppb analyte concentration ranges. The LIA-based sensor signal recognition technique has shown to extend the capabilities of the gas sensor array for a linear discrimination analysis (LDA), an independent component analysis (ICA), a principal component analysis (PCA) and other multiple odor recognition methods.

  18. Alcoholism and Alcohol Abuse

    MedlinePlus

    ... This means that their drinking causes distress and harm. It includes alcoholism and alcohol abuse. Alcoholism, or ... brain, and other organs. Drinking during pregnancy can harm your baby. Alcohol also increases the risk of ...

  19. MEMS based Low Cost Piezoresistive Microcantilever Force Sensor and Sensor Module

    PubMed Central

    Pandya, H. J.; Kim, Hyun Tae; Roy, Rajarshi; Desai, Jaydev P.

    2014-01-01

    In the present work, we report fabrication and characterization of a low-cost MEMS based piezoresistive micro-force sensor with SU-8 tip using laboratory made silicon-on-insulator (SOI) substrate. To prepare SOI wafer, silicon film (0.8 µm thick) was deposited on an oxidized silicon wafer using RF magnetron sputtering technique. The films were deposited in Argon (Ar) ambient without external substrate heating. The material characteristics of the sputtered deposited silicon film and silicon film annealed at different temperatures (400–1050°C) were studied using atomic force microscopy (AFM) and X-ray diffraction (XRD) techniques. The residual stress of the films was measured as a function of annealing temperature. The stress of the as-deposited films was observed to be compressive and annealing the film above 1050°C resulted in a tensile stress. The stress of the film decreased gradually with increase in annealing temperature. The fabricated cantilevers were 130 µm in length, 40 µm wide and 1.0 µm thick. A series of force-displacement curves were obtained using fabricated microcantilever with commercial AFM setup and the data were analyzed to get the spring constant and the sensitivity of the fabricated microcantilever. The measured spring constant and sensitivity of the sensor was 0.1488N/m and 2.7mV/N. The microcantilever force sensor was integrated with an electronic module that detects the change in resistance of the sensor with respect to the applied force and displays it on the computer screen. PMID:24855449

  20. Coverage in Wireless Sensor Network Based on Probabilistic Sensing Model

    NASA Astrophysics Data System (ADS)

    Li, Fen; Deng, Kai; Meng, Fanzhi; Weiyan, Zhang

    One of the major problem to consider in designing wireless sensor network is how to extend the network lifetime and provide desired quality of service. To achieve this, a broadly-used method is topology control. This paper studies the problem of how to ensure the network fully connected without nodes' location information. The coverage control model based on probabilistic sensing model is proposed in this paper. With random sensor deployment, the sensing node and communicating node number can be calculated based on the size of sensing region and the performance parameters of node (e.g., node sensing radius, communication radius, and so on). Simulation results show that the actual coverage quality provided by sensing nodes scheduled with the proposed coverage control model is higher than the threshold of coverage quality.

  1. Silica microwire-based interferometric electric field sensor.

    PubMed

    Han, Chunyang; Lv, Fangxing; Sun, Chen; Ding, Hui

    2015-08-15

    Silica microwire, as an optical waveguide whose diameter is close to or smaller than the wavelength of the guided light, is of great interest because it exhibits a number of excellent properties such as tight confinement, large evanescent fields, and great configurability. Here, we report a silica microwire-based compact photonic sensor for real-time detection of high electric field. This device contains an interferometer with propylene carbonate cladding. Based on the Kerr electro-optic effect of propylene carbonate, the applied intensive transient electric field can change the refractive index of propylene carbonate, which shifts the interferometric fringe. Therefore, the electric field could be demodulated by monitoring the fringe shift. The sensor was successfully used to detect alternating electric field with frequency of 50 Hz and impulse electric field with duration time of 200 μs. This work lays a foundation for future applications in electric field sensing. PMID:26274634

  2. Chlorhexidine alcohol base mouthrinse versus Chlorhexidine formaldehyde base mouthrinse efficacy on plaque control: Double blind, randomized clinical trials

    PubMed Central

    Lakhdar, Leila; Bouziane, Amal; Bensouda, Yahia; Abouqal, Redouane

    2013-01-01

    Background: Chlorhexidine is well known for its antiplaque effect. However, the mouthrinse based chlorhexidine antiplaque efficiency may vary according to the formulation of the final product. The aim of the present study was to compare anti-plaque effectiveness of two commercial mouthrinses: 0.12 % Chlorhexidine alcohol base (CLX-A) versus a diluted 0.1% Chlorhexidine non-alcohol base with 0.1% of Formaldehyde (CLX-F). Material and Methods: the study was a seven day randomized, double-blind, placebo-controlled trial including 30 volunteers. At the start, all participants received a dental prophylaxis. Over 7 days experimental non-brushing period, during which subjects abstained from all forms of mechanical oral hygiene, one group test rinsed twice daily with 15ml of an alcohol base 0.12% Chlorhexidine mouthrinse. The second group test used 15ml of alcohol free 0.1% Chlorhexidine mouthrinse base 0.1% formaldehyde twice daily. The negative control group used a placebo. Plaque indexes were recorded in all volunteers prior to treatment at Day 0, 1 and 7. Results: After 7 days, the mean plaque index for the first group was 0.76±0.38 compared with a mean plaque index of 1.43±0.56 for the second group. The difference in plaque scores between the groups was statistically significant. Conclusion: the results of this study showed that rinsing with an alcohol base 0.12% Chlorhexidine mouthrinse is significantly different from rinsing with an alcohol free 0.1% Chlorhexidine mouthrinse on plaque inhibition. Key words:Chlorhexidine, dental plaque, mouthrinse, alcohol, formaldehyde. PMID:23229237

  3. Two Fully Automated Web-Based Interventions for Risky Alcohol Use: Randomized Controlled Trial

    PubMed Central

    Strüber, Evelin

    2013-01-01

    Background Excessive alcohol use is a widespread problem in many countries, especially among young people. To reach more people engaging in high-risk drinking behaviors, a number of online programs have been developed in recent years. Change Your Drinking is a German, diary-based, fully automated alcohol intervention. In 2010, a revised version of the program was developed. It is more strongly oriented to concepts of relapse prevention than the previous version, includes more feedback, and offers more possibilities to interact with the program. Moreover, the program duration was extended from 10 to 14 days. Objective This paper examines whether the revised version of Change Your Drinking is more effective in reducing alcohol consumption than the original version. Methods The effectiveness of both program versions was compared in a Web-based, open, randomized controlled trial with follow-up surveys 6 weeks and 3 months after registration. Participants were recruited online and were randomly assigned to either the original or the revised version of Change Your Drinking. The following self-assessed outcomes were used: alcohol use days, alcohol intake in grams, the occurrence of binge drinking and risky drinking (all referring to the past 7 days prior to each survey), and the number of alcohol-related problems. Results A total of 595 participants were included in the trial. Follow-up rates were 58.0% after 6 weeks and 49.6% after 3 months. No significant group differences were found in any of the outcomes. However, the revised version was used by more participants (80.7%) than the original version (55.7%). A significant time effect was detected in all outcomes (alcohol use days: P=.002; alcohol intake in grams: P<.001; binge drinking: P<.001; alcohol-related problems: P=.004; risky drinking: P<.001). Conclusions The duration and complexity of the program played a minor role in reducing alcohol consumption. However, differences in program usage between the versions

  4. Optical Sensors Based on Single on Arm Thin Film Waveguide Interferometer

    NASA Technical Reports Server (NTRS)

    Sarkisov, S. S.; Diggs, D.; Curley, M.; Adamovsky, Grigory (Technical Monitor)

    2000-01-01

    Single-arm dual-mode optical waveguide interferometer utilizes interference between two modes of different order. Sensing effect results from the change in propagation conditions of the modes caused by the environment. The waveguide is made as an open asymmetric structure containing a dye-doped polymer film onto a quartz substrate. It is more sensitive to the change of environment than its conventional polarimetric analog using orthogonal modes (TE and TM) of the same order. The sensor still preserves the option of operating in polarimetric regime using a variety of mode combinations such as TE(sub 0)/TM(sub 0) (conventional) TE(sub 0)/TM(sub 1), TE(sub 1)/TM(sub 0), or TE(sub 1)/TM(sub 1) but can also work in nonpolarimetric regime using combinations TE(sub 0)/TE(sub 1) or TM(sub 0)/TM(sub 1). Utilization of different mode combinations simultaneously makes the device more versatile. Application of the sensor to gas sensing is based on doping polymer film with an organic indicator dye targeting a particular gaseous reagent. Change of the optical absorption spectrum of the dye caused by the gaseous pollutant results in change of the reactive index of the dye-doped polymer film that can be detected by the sensor. As indicator dyes we utilize Bromocresol Purple doped into polymer poly(methyl) methacrylate that is sensitive to small concentrations of ammonia. The indicator dye demonstrated an irreversible increase in optical absorption near the peak at 350 nm being exposed to 5% ammonia in pure nitrogen at 600 Torr. The dye also showed reversible growth of the absorption peak near 600 nm after exposure to a vapor of standard medical ammonia spirit (65% alcohol). We have built a breadboard prototype of the sensor with He-Ne laser as a light source and with a single mode fiber input and a multimode fiber output. The prototype showed a sensitivity to temperature change of the order of 2 C per 2pi phase shift. The sensitivity of the sensor to the presence of dTy ammonia is

  5. A ph sensor based on a flexible substrate

    NASA Astrophysics Data System (ADS)

    Huang, Wen-Ding

    pH sensor is an essential component used in many chemical, food, and bio-material industries. Conventional glass electrodes have been used to construct pH sensors, however, have some disadvantages. Glass electrodes are easily affected by alkaline or HF solution, they require a high input impedance pH meter, they often exhibit a sluggish response. In some specific applications, it is also difficult to use glass electrodes for in vivo biomedical or food monitoring applications due to the difficulty of size miniaturization, planarization and polymerization based on current manufacturing technologies. In this work, we have demonstrated a novel flexible pH sensor based on low-cost sol-gel fabrication process of iridium oxide (IrOx) sensing film (IROF). A pair of flexible miniature IrOx/AgCl electrode generated the action potential from the solution by electrochemical mechanism to obtain the pH level of the reagent. The fabrication process including sol-gel, thermal oxidation, and the electro-plating process of the silver chloride (AgCl) reference electrode were reported in the work. The IrOx film was verified and characterized using electron dispersive analysis (EDAX), scanning electron microscope (SEM), and x-ray diffraction (XRD). The flexible pH sensor's performance and characterization have been investigated with different testing parameters such as sensitivity, response time, stability, reversibility, repeatability, selectivity and temperature dependence. The flexible IrOx pH sensors exhibited promising sensing performance with a near-Nernstian response of sensitivity which is between --51.1mV/pH and --51.7mV/pH in different pH levels ranging from 1.5 to 12 at 25°C. Two applications including gastroesophageal reflux disease (GERD) diagnosis and food freshness wireless monitoring using our micro-flexible IrOx pH sensors were demonstrated. For the GERD diagnosing system, we embedded the micro flexible pH sensor on a 1.2cmx3.8cm of the capsule size of wireless sensor

  6. Plasmonic Sensors Based on Doubly-Deposited Tapered Optical Fibers

    PubMed Central

    González-Cano, Agustín; Navarrete, María-Cruz; Esteban, Óscar; Díaz-Herrera, Natalia

    2014-01-01

    A review of the surface plasmon resonance (SPR) transducers based on tapered fibers that have been developed in the last years is presented. The devices have proved their good performance (specifically, in terms of sensitivity) and their versatility and they are a very good option to be considered as basis for any kind of chemical and biological sensor. The technology has now reached its maturity and here we summarize some of the characteristics of the devices produced. PMID:24618726

  7. A fluorescence enhancement-based sensor for hydrogen sulfate ion.

    PubMed

    Yang, Shih-Tse; Liao, De-Jhong; Chen, Shau-Jiun; Hu, Ching-Han; Wu, An-Tai

    2012-04-01

    Sugar-aza-crown ether-based cavitand 1 can act as a selective turn-on fluorescence sensor for hydrogen sulfate ion in methanol among a series of tested anions. Spectroscopic studies, particularly NMR spectroscopy, revealed that the C-H hydrogen bonding between 1,2,3-triazole ring of cavitand 1 and hydrogen sulfate ion is crucial for the high selectivity of the receptor for hydrogen sulfate. PMID:22363932

  8. Engineering Paper-Based Sensors for Zika Virus.

    PubMed

    Meagher, Robert J; Negrete, Oscar A; Van Rompay, Koen K

    2016-07-01

    The emergence of Zika virus (ZIKV) infections in Latin America and Southeast Asia has created an urgent need for new, simple, yet sensitive, diagnostic tests. We highlight recent work using paper-based sensors coupled with CRISPR/Cas9 to detect ZIKV RNA as a new approach to achieve rapid development and deployment of field-ready diagnostics for emerging infectious diseases. PMID:27255410

  9. Luminescence-based optical sensor systems for monitoring water parameters

    NASA Astrophysics Data System (ADS)

    Lobnik, Aleksandra; Turel, Matejka; Korent, Špela Mojca

    2007-06-01

    Lanthanide-sensitized luminescence is very attractive because the intramolecular energy transfers between the absorbing ligand and the luminescent ion results in strong narrow-band fluorescence with a large Stokes' shift and long decay times. We will report about several sensor systems based either on sol-gel materials or lanthanide chelates for monitoring and controlling water parameters, such as heavy metals, amines, phosphates.

  10. Building SDN-Based Agricultural Vehicular Sensor Networks Based on Extended Open vSwitch.

    PubMed

    Huang, Tao; Yan, Siyu; Yang, Fan; Pan, Tian; Liu, Jiang

    2016-01-01

    Software-defined vehicular sensor networks in agriculture, such as autonomous vehicle navigation based on wireless multi-sensor networks, can lead to more efficient precision agriculture. In SDN-based vehicle sensor networks, the data plane is simplified and becomes more efficient by introducing a centralized controller. However, in a wireless environment, the main controller node may leave the sensor network due to the dynamic topology change or the unstable wireless signal, leaving the rest of network devices without control, e.g., a sensor node as a switch may forward packets according to stale rules until the controller updates the flow table entries. To solve this problem, this paper proposes a novel SDN-based vehicular sensor networks architecture which can minimize the performance penalty of controller connection loss. We achieve this by designing a connection state detection and self-learning mechanism. We build prototypes based on extended Open vSwitch and Ryu. The experimental results show that the recovery time from controller connection loss is under 100 ms and it keeps rule updating in real time with a stable throughput. This architecture enhances the survivability and stability of SDN-based vehicular sensor networks in precision agriculture. PMID:26797616

  11. Building SDN-Based Agricultural Vehicular Sensor Networks Based on Extended Open vSwitch

    PubMed Central

    Huang, Tao; Yan, Siyu; Yang, Fan; Pan, Tian; Liu, Jiang

    2016-01-01

    Software-defined vehicular sensor networks in agriculture, such as autonomous vehicle navigation based on wireless multi-sensor networks, can lead to more efficient precision agriculture. In SDN-based vehicle sensor networks, the data plane is simplified and becomes more efficient by introducing a centralized controller. However, in a wireless environment, the main controller node may leave the sensor network due to the dynamic topology change or the unstable wireless signal, leaving the rest of network devices without control, e.g., a sensor node as a switch may forward packets according to stale rules until the controller updates the flow table entries. To solve this problem, this paper proposes a novel SDN-based vehicular sensor networks architecture which can minimize the performance penalty of controller connection loss. We achieve this by designing a connection state detection and self-learning mechanism. We build prototypes based on extended Open vSwitch and Ryu. The experimental results show that the recovery time from controller connection loss is under 100 ms and it keeps rule updating in real time with a stable throughput. This architecture enhances the survivability and stability of SDN-based vehicular sensor networks in precision agriculture. PMID:26797616

  12. Graphene Based Electrochemical Sensors and Biosensors: A Review

    SciTech Connect

    Shao, Yuyan; Wang, Jun; Wu, Hong; Liu, Jun; Aksay, Ilhan A.; Lin, Yuehe

    2010-05-01

    Graphene, emerging as a true 2-dimensional material, has received increasing attention due to its unique physicochemical properties (high surface area, excellent conductivity, high mechanical strength, and ease of functionalization and mass production). This article selectively reviews recent advances in graphene-based electrochemical sensors and biosensors. In particular, graphene for direct electrochemistry of enzyme, its electrocatalytic activity toward small biomolecules (hydrogen peroxide, NADH, dopamine, etc.), and graphene-based enzyme biosensors have been summarized in more detail; Graphene-based DNA sensing and environmental analysis have been discussed. Future perspectives in this rapidly developing field are also discussed.

  13. Bridge monitoring based on smart sensor data acquisition system

    NASA Astrophysics Data System (ADS)

    Ehrlich, Jacques; Eymard, Robert; Coche, Georges

    1996-04-01

    The knowledge of loads applied to bridges has to be enhanced in order to actualize national and international codes, like Eurocodes. The nature of traffic loads is extremely complex including such phenomena as dynamic effects, random distribution of damping techniques over the actual trucks, multiple non-linear visco-elastic links in mechanical description of a given truck. For all these reasons, a system of monitoring bridges has been preferred to an unrigorous modelling, in order to get a statistical knowledge of the traffic loads applied to the bridge over large periods. This knowledge under the form of histograms will be useful in order to evaluate extreme load effects and fatigue load effects over the lifetime of the bridge. To achieve these goals, a data acquisition system based on smart sensors extracting and classifying extrema in the traffic loads signal has been developed. At each measurement site a small microsystem is dedicated to the tasks of signal conditioning and sampling, calculation and communication. Each smart sensor can communicate through a numerical data link with its neighbors or with a PC based system controller. In this paper an outline of the problem, the proposed solution based on the smart sensor paradigm, and the results which have been obtained are presented.

  14. Intent-based resource deployment in wireless sensor networks

    NASA Astrophysics Data System (ADS)

    de Mel, Geeth; Pham, Tien; Sullivan, Paul; Grueneberg, Keith; Vasconcelos, Wamberto; Norman, Tim

    2012-06-01

    Information derived from sensor networks plays a crucial role in the success of many critical tasks such as surveillance, and border monitoring. In order to derive the correct information at the right time, sensor data must be captured at desired locations with respect to the operational tasks in concern. Therefore, it is important that at the planning stage of a mission, sensing resources are best placed in the field to capture the required data. For example, consider a mission goal identify snipers, in an operational area before troops are deployed - two acoustic arrays and a day-night video camera are needed to successfully achieve this goal. This is because, if the resources are placed in correct locations, two acoustic arrays could provide direction of the shooter and a possible location by triangulating acoustic data whereas the day-night camera could produce an affirmative image of the perpetrators. In order to deploy the sensing resources intelligently to support the user decisions, in this paper we propose a Semantic Web based knowledge layer to identify the required resources in a sensor network and deploy the needed resources through a sensor infrastructure. The knowledge layer captures crucial information such as resources configurations, their intended use (e.g., two acoustic arrays deployed in a particular formation with day-night camera are needed to identify perpetrators in a possible sniper attack). The underlying sensor infrastructure will assists the process by exposing the information about deployed resources, resources in theatre, and location information about tasks, resources and so on.

  15. A model-based reasoning approach to sensor placement for monitorability

    NASA Technical Reports Server (NTRS)

    Chien, Steve; Doyle, Richard; Homemdemello, Luiz

    1992-01-01

    An approach is presented to evaluating sensor placements to maximize monitorability of the target system while minimizing the number of sensors. The approach uses a model of the monitored system to score potential sensor placements on the basis of four monitorability criteria. The scores can then be analyzed to produce a recommended sensor set. An example from our NASA application domain is used to illustrate our model-based approach to sensor placement.

  16. A ph sensor based on a flexible substrate

    NASA Astrophysics Data System (ADS)

    Huang, Wen-Ding

    pH sensor is an essential component used in many chemical, food, and bio-material industries. Conventional glass electrodes have been used to construct pH sensors, however, have some disadvantages. Glass electrodes are easily affected by alkaline or HF solution, they require a high input impedance pH meter, they often exhibit a sluggish response. In some specific applications, it is also difficult to use glass electrodes for in vivo biomedical or food monitoring applications due to the difficulty of size miniaturization, planarization and polymerization based on current manufacturing technologies. In this work, we have demonstrated a novel flexible pH sensor based on low-cost sol-gel fabrication process of iridium oxide (IrOx) sensing film (IROF). A pair of flexible miniature IrOx/AgCl electrode generated the action potential from the solution by electrochemical mechanism to obtain the pH level of the reagent. The fabrication process including sol-gel, thermal oxidation, and the electro-plating process of the silver chloride (AgCl) reference electrode were reported in the work. The IrOx film was verified and characterized using electron dispersive analysis (EDAX), scanning electron microscope (SEM), and x-ray diffraction (XRD). The flexible pH sensor's performance and characterization have been investigated with different testing parameters such as sensitivity, response time, stability, reversibility, repeatability, selectivity and temperature dependence. The flexible IrOx pH sensors exhibited promising sensing performance with a near-Nernstian response of sensitivity which is between --51.1mV/pH and --51.7mV/pH in different pH levels ranging from 1.5 to 12 at 25°C. Two applications including gastroesophageal reflux disease (GERD) diagnosis and food freshness wireless monitoring using our micro-flexible IrOx pH sensors were demonstrated. For the GERD diagnosing system, we embedded the micro flexible pH sensor on a 1.2cmx3.8cm of the capsule size of wireless sensor

  17. A fuzzy behaviorist approach to sensor-based robot control

    SciTech Connect

    Pin, F.G.

    1996-05-01

    Sensor-based operation of autonomous robots in unstructured and/or outdoor environments has revealed to be an extremely challenging problem, mainly because of the difficulties encountered when attempting to represent the many uncertainties which are always present in the real world. These uncertainties are primarily due to sensor imprecisions and unpredictability of the environment, i.e., lack of full knowledge of the environment characteristics and dynamics. An approach. which we have named the {open_quotes}Fuzzy Behaviorist Approach{close_quotes} (FBA) is proposed in an attempt to remedy some of these difficulties. This approach is based on the representation of the system`s uncertainties using Fuzzy Set Theory-based approximations and on the representation of the reasoning and control schemes as sets of elemental behaviors. Using the FBA, a formalism for rule base development and an automated generator of fuzzy rules have been developed. This automated system can automatically construct the set of membership functions corresponding to fuzzy behaviors. Once these have been expressed in qualitative terms by the user. The system also checks for completeness of the rule base and for non-redundancy of the rules (which has traditionally been a major hurdle in rule base development). Two major conceptual features, the suppression and inhibition mechanisms which allow to express a dominance between behaviors are discussed in detail. Some experimental results obtained with the automated fuzzy, rule generator applied to the domain of sensor-based navigation in aprion unknown environments. using one of our autonomous test-bed robots as well as a real car in outdoor environments, are then reviewed and discussed to illustrate the feasibility of large-scale automatic fuzzy rule generation using the {open_quotes}Fuzzy Behaviorist{close_quotes} concepts.

  18. Reducing Children's Susceptibility to Alcohol Use: Effects of a Home-Based Parenting Program.

    PubMed

    Jackson, Christine; Ennett, Susan T; Reyes, H Luz McNaughton; Hayes, Kim A; Dickinson, Denise M; Choi, Seulki; Bowling, J Michael

    2016-07-01

    This 4-year efficacy trial tested whether a home-based, self-administered parenting program could have a long-term effect on children's cognitive susceptibility to alcohol use, and it tested hypothesized moderators and mediators of any such program effect. Using a two-group randomized controlled design, 1076 children (540 treatment; 536 control; mean age of 9.2 years at baseline) completed telephone interviews prior to randomization and follow-up interviews 12, 24, 36, and 48 months post-baseline. Mothers of children randomized to treatment received a 5-month-long parenting program during year 1, followed by two 1-month-long boosters in years 2 and 3. Exposure to the program was significantly inversely associated with susceptibility to alcohol use 48 months post-baseline (b = -0.03, p = .04), with no variation in program effects by parental alcohol use or mother's race/ethnicity or education, suggesting broad public health relevance of the parenting program. Path analyses of simple indirect effects through each hypothesized mediator showed that program exposure positively influenced parental communication to counter pro-drinking influences in the family and media domains and parental rule setting 36 months post-baseline; these variables, in turn, predicted reduced susceptibility to alcohol use 48 months post-baseline. Parallel (multiple) mediation analysis showed that the program had a significant indirect effect on susceptibility through parental rule setting. Together, the findings indicate that internalization of protective alcohol-related expectancies and intentions is possible among children whose mothers provide early exposure to alcohol-specific socialization. Additional research is needed to link alcohol-specific socialization during childhood with adolescent drinking outcomes. PMID:27154767

  19. Alcohol Use to Facilitate a Suicide Attempt: An Event-Based Examination

    PubMed Central

    Bagge, Courtney L.; Conner, Kenneth R.; Reed, Louren; Dawkins, Milton; Murray, Kevin

    2015-01-01

    Objective: The current study is based on the hypothesis that alcohol-involved suicide attempts are characterized by lower premeditation and intent, but only when the use of alcohol is not motivated by the desire to facilitate the attempt. Test of this idea was conducted by comparing proximal suicide premeditation and intent of suicide attempts among three groups: individuals who (a) drank to facilitate the attempt (e.g., to “numb fears” about attempting), (b) drank for nonfacilitative motives, and (c) did not use alcohol before the attempt. Method: Participants included 324 (62% female) recent suicide attempters presenting to a Level 1 trauma hospital. The Timeline Followback Interview for Suicide Attempts and a novel Suicide Facilitative Drinking Motives Scale were used to assess facilitative motives for drinking and characteristics of the attempt. Results: One third of participants drank before the attempt, and most (73%) who used alcohol did not do so to facilitate the attempt. As hypothesized, attempts carried out by this group had shorter proximal suicide premeditation and lower suicide intent compared with the other study groups; in contrast, individuals who drank to facilitate the attempt were similar to non–alcohol users on these indices. Conclusions: Alcohol-involved suicide attempts are heterogeneous. Motives for drinking are a key source of heterogeneity insofar as fundamental characteristics of attempts (proximal premeditation, intent) differ as a function of drinking motivation. Clinical implications include that individuals making suicide attempts with facilitative motives for drinking cannot be assumed to be at lowered risk upon a drop in blood alcohol level. PMID:25978835

  20. Alcohol Drinking Patterns and Differences in Alcohol-Related Harm: A Population-Based Study of the United States

    PubMed Central

    Antai, D.; Lopez, G. B.; Antai, J.; Anthony, D. S.

    2014-01-01

    Alcohol use and associated alcohol-related harm (ARH) are a prevalent and important public health problem, with alcohol representing about 4% of the global burden of disease. A discussion of ARH secondary to alcohol consumption necessitates a consideration of the amount of alcohol consumed and the drinking pattern. This study examined the association between alcohol drinking patterns and self-reported ARH. Pearson chi-square test (χ2) and logistic regression analyses were used on data from the National Comorbidity Survey Replication (NCS-R). The NCS-R is a cross-sectional nationally representative sample. Data was obtained by face-to-face interviews from 9282 adults aged ≥18 years in the full sample, and 5,692 respondents in a subsample of the full sample. Results presented as odds ratio (OR) and 95% confidence intervals (95% CI). Alcohol drinking patterns (frequency of drinking, and drinks per occasion) were associated with increased risks of self-reported ARH; binge or “risky” drinking was strongly predictive of ARH than other categories of drinks per occasion or frequency of drinking; and men had significantly higher likelihood of ARH in relation to frequency of drinking and drinks per occasion. Findings provide evidence for public health practitioners to target alcohol prevention strategies at the entire population of drinkers. PMID:25057502

  1. UV-visible sensors based on polymorphous silicon

    NASA Astrophysics Data System (ADS)

    Guedj, Cyril S.; Cabarrocas, Pere R. i.; Massoni, Nicolas; Moussy, Norbert; Morel, Damien; Tchakarov, Svetoslav; Bonnassieux, Yvan

    2003-09-01

    UV-based imaging systems can be used for low-altitude rockets detection or biological agents identification (for instance weapons containing ANTHRAX). Compared to conventional CCD technology, CMOS-based active pixel sensors provide several advantages, including excellent electro-optical performances, high integration, low voltage operation, low power consumption, low cost, long lifetime, and robustness against environment. The monolithic integration of UV, visible and infrared detectors on the same uncooled CMOS smart system would therefore represent a major advance in the combat field, for characterization and representation of targets and backgrounds. In this approach, we have recently developped a novel technology using polymorphous silicon. This new material, fully compatible with above-IC silicon technology, is made of nanometric size ordered domains embedded in an amorphous matrix. The typical quantum efficiency of detectors made of this nano-material reach up to 80 % at 550 nm and 30 % in the UV range, depending of the design and the growth parameters. Furthermore, a record dark current of 20 pA/cm2 at -3 V has been reached. In addition, this new generation of sensors is significantly faster and more stable than their amorphous silicon counterparts. In this paper, we will present the relationship between the sensor technology and the overall performances.

  2. Sensor-based control of a nine-link biped

    SciTech Connect

    Furusho, J.; Sano, A. )

    1990-04-01

    The authors aimed to realize smooth 3D biped walking in a robot through control based on information obtained from various sensors. They employed a method to control walking by dividing it into motions in the sagittal plane and in the lateral plane. They treated motion in the lateral plane as a regulator problem with two equilibrium states. They also used relatively low gain feedback coefficients obtained from the optimal regulator theory. For motion in the sagittal plane, they put the body speed close to the smooth speed function given in advance by controlling the ankle torque. The effectiveness of the proposed control method was examined by computer simulation and proved by experiments with out BLR-G2 walking robot. The BLR-G2 is equipped with foot pressure and ankle torque sensors to provide information about the condition of contact with the floor. The sole and ankle driving actuators undergo force/torque feedback control based on the sensor information. These contributed toward realizing smooth walking with the sole firmly gripping the floor.

  3. Inertial Sensor-Based Smoother for Gait Analysis

    PubMed Central

    Suh, Young Soo

    2014-01-01

    An off-line smoother algorithm is proposed to estimate foot motion using an inertial sensor unit (three-axis gyroscopes and accelerometers) attached to a shoe. The smoother gives more accurate foot motion estimation than filter-based algorithms by using all of the sensor data instead of using the current sensor data. The algorithm consists of two parts. In the first part, a Kalman filter is used to obtain initial foot motion estimation. In the second part, the error in the initial estimation is compensated using a smoother, where the problem is formulated in the quadratic optimization problem. An efficient solution of the quadratic optimization problem is given using the sparse structure. Through experiments, it is shown that the proposed algorithm can estimate foot motion more accurately than a filter-based algorithm with reasonable computation time. In particular, there is significant improvement in the foot motion estimation when the foot is moving off the floor: the z-axis position error squared sum (total time: 3.47 s) when the foot is in the air is 0.0807 m2 (Kalman filter) and 0.0020 m2 (the proposed smoother). PMID:25526359

  4. Miniature fiber optic sensor based on fluorescence energy transfer

    NASA Astrophysics Data System (ADS)

    Meadows, David L.; Schultz, Jerome S.

    1992-04-01

    Optical fiber biosensors based on fluorescence assays have several distinct advantages when measuring biological analytes such as metabolites, cofactors, toxins, etc. Not only are optical signals immune to electronic interferences, but the polychromatic nature of most fluorochemical assays provides more potentially useful data about the system being studied. One of the most common difficulties normally encountered with optical biosensors is the inability to routinely recalibrate the optical and electronic components of the system throughout the life of the sensor. With this in mind, we present an optical fiber assay system for glucose based on a homogeneous singlet/singlet energy transfer assay along with the electronic instrumentation built to support the sensor system. In the sensor probe, glucose concentrations are indirectly measured from the level of fluorescence quenching caused by the homogeneous competition assay between TRITC labeled concanavalin A (receptor) and FITC labeled Dextran (ligand). The FITC signal is used to indicate glucose concentrations and the TRITC signal is used for internal calibration. Data is also presented on a protein derivatization procedure that was used to prevent aggregation of the receptor protein in solution. Also, a molecular model is described for the singlet/singlet energy transfer interactions that can occur in a model system composed of a monovalent ligand (FITC labeled papain) and a monovalent receptor (TRITC labeled concanavalin A).

  5. Vision Sensor-Based Road Detection for Field Robot Navigation

    PubMed Central

    Lu, Keyu; Li, Jian; An, Xiangjing; He, Hangen

    2015-01-01

    Road detection is an essential component of field robot navigation systems. Vision sensors play an important role in road detection for their great potential in environmental perception. In this paper, we propose a hierarchical vision sensor-based method for robust road detection in challenging road scenes. More specifically, for a given road image captured by an on-board vision sensor, we introduce a multiple population genetic algorithm (MPGA)-based approach for efficient road vanishing point detection. Superpixel-level seeds are then selected in an unsupervised way using a clustering strategy. Then, according to the GrowCut framework, the seeds proliferate and iteratively try to occupy their neighbors. After convergence, the initial road segment is obtained. Finally, in order to achieve a globally-consistent road segment, the initial road segment is refined using the conditional random field (CRF) framework, which integrates high-level information into road detection. We perform several experiments to evaluate the common performance, scale sensitivity and noise sensitivity of the proposed method. The experimental results demonstrate that the proposed method exhibits high robustness compared to the state of the art. PMID:26610514

  6. Usage Based Building Management through Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    Erickson, Varick L.

    Wireless sensor networks (WSNs) is a field with broad variety of applications. Its flexibility for remote continuous measurement lends itself to applications ranging from locating snipers to measuring volcanic activity. One application that stands to substantially benefit from WSNs is building management. Buildings currently account for 41% of the total energy consumption of U.S. [bed11]. Reducing this energy is of critical importance if we are to achieve sustainability. In most commercial buildings, many rooms remain unoccupied or are conditioned assuming maximum occupancy. By relaxing temperature setbacks and adjusting ventilation to match actual occupancy, significant energy savings are possible. This Dissertation examines the use of wireless sensor networks for the purpose of building energy management and actuation. It explores the design and development of wireless sensor networks for building energy management, how data from these deployments are utilized, the development and implementation of data driven occupancy models to perform simulation and prediction, how data models are used to actuate building management systems, and how crowd-sourced data can be integrated into building control strategies. We show based on real-world data that 30% energy savings is possible through usage based strategies and that 80% occupant satisfaction rates are possible by occupant driven control strategies.

  7. Vision Sensor-Based Road Detection for Field Robot Navigation.

    PubMed

    Lu, Keyu; Li, Jian; An, Xiangjing; He, Hangen

    2015-01-01

    Road detection is an essential component of field robot navigation systems. Vision sensors play an important role in road detection for their great potential in environmental perception. In this paper, we propose a hierarchical vision sensor-based method for robust road detection in challenging road scenes. More specifically, for a given road image captured by an on-board vision sensor, we introduce a multiple population genetic algorithm (MPGA)-based approach for efficient road vanishing point detection. Superpixel-level seeds are then selected in an unsupervised way using a clustering strategy. Then, according to the GrowCut framework, the seeds proliferate and iteratively try to occupy their neighbors. After convergence, the initial road segment is obtained. Finally, in order to achieve a globally-consistent road segment, the initial road segment is refined using the conditional random field (CRF) framework, which integrates high-level information into road detection. We perform several experiments to evaluate the common performance, scale sensitivity and noise sensitivity of the proposed method. The experimental results demonstrate that the proposed method exhibits high robustness compared to the state of the art. PMID:26610514

  8. Discrete-Time ARMAv Model-Based Optimal Sensor Placement

    SciTech Connect

    Song Wei; Dyke, Shirley J.

    2008-07-08

    This paper concentrates on the optimal sensor placement problem in ambient vibration based structural health monitoring. More specifically, the paper examines the covariance of estimated parameters during system identification using auto-regressive and moving average vector (ARMAv) model. By utilizing the discrete-time steady state Kalman filter, this paper realizes the structure's finite element (FE) model under broad-band white noise excitations using an ARMAv model. Based on the asymptotic distribution of the parameter estimates of the ARMAv model, both a theoretical closed form and a numerical estimate form of the covariance of the estimates are obtained. Introducing the information entropy (differential entropy) measure, as well as various matrix norms, this paper attempts to find a reasonable measure to the uncertainties embedded in the ARMAv model estimates. Thus, it is possible to select the optimal sensor placement that would lead to the smallest uncertainties during the ARMAv identification process. Two numerical examples are provided to demonstrate the methodology and compare the sensor placement results upon various measures.

  9. Theory for a gas composition sensor based on acoustic properties

    NASA Technical Reports Server (NTRS)

    Phillips, Scott; Dain, Yefim; Lueptow, Richard M.

    2003-01-01

    Sound travelling through a gas propagates at different speeds and its intensity attenuates to different degrees depending upon the composition of the gas. Theoretically, a real-time gaseous composition sensor could be based on measuring the sound speed and the acoustic attenuation. To this end, the speed of sound was modelled using standard relations, and the acoustic attenuation was modelled using the theory for vibrational relaxation of gas molecules. The concept for a gas composition sensor is demonstrated theoretically for nitrogen-methane-water and hydrogen-oxygen-water mixtures. For a three-component gas mixture, the measured sound speed and acoustic attenuation each define separate lines in the composition plane of two of the gases. The intersection of the two lines defines the gas composition. It should also be possible to use the concept for mixtures of more than three components, if the nature of the gas composition is known to some extent.

  10. Theory for a gas composition sensor based on acoustic properties.

    PubMed

    Phillips, Scott; Dain, Yefim; Lueptow, Richard M

    2003-01-01

    Sound travelling through a gas propagates at different speeds and its intensity attenuates to different degrees depending upon the composition of the gas. Theoretically, a real-time gaseous composition sensor could be based on measuring the sound speed and the acoustic attenuation. To this end, the speed of sound was modelled using standard relations, and the acoustic attenuation was modelled using the theory for vibrational relaxation of gas molecules. The concept for a gas composition sensor is demonstrated theoretically for nitrogen-methane-water and hydrogen-oxygen-water mixtures. For a three-component gas mixture, the measured sound speed and acoustic attenuation each define separate lines in the composition plane of two of the gases. The intersection of the two lines defines the gas composition. It should also be possible to use the concept for mixtures of more than three components, if the nature of the gas composition is known to some extent. PMID:14552356

  11. A New Fluorescent Sensor Based on Bisindolizine Derivative.

    PubMed

    I, Anitha; M, Sheela Gopal; Thomas, Divya

    2016-03-01

    A fluorescent sensor based on 1,2,1',2'- Tetra(methoxycarbonyl)- 3,3'- bis(p-methylbenzoyl)- 7,7'-bisindolizine (MBI) showing excellent selectivity towards Fe(3+) ions was developed. Under optimized experimental conditions, the fluorescence intensity of 1,2,1',2'- Tetramethoxycarbonyl- 3,3'- bis(p-methylbenzoyl)- 7,7'-bisindolizine was quenched linearly by Fe(3+) ions in the range of 2.00 × 10(-2) to 4.76 × 10(-3) M. The limit of detection was found to be 3.17 × 10(-3) M. The mechanism for quenching was investigated. The developed sensor was applied for the determination of Fe(3+) in pharmaceutical samples. PMID:26758054

  12. Amylin Detection with a Miniature Optical-Fiber Based Sensor

    NASA Astrophysics Data System (ADS)

    Liu, Zhaowen; Ann, Matsko; Hughes, Adam; Reeves, Mark

    We present results of a biosensor based on shifts in the localized surface plasmon resonance of gold nanoparticles self-assembled on the end of an optical fiber. This system allows for detection of protein expression in low sensing volumes and for scanning in cell cultures and tissue samples. Positive and negative controls were done using biotin/avidin and the BSA/Anti-BSA system. These demonstrate that detection is specific and sensitive to nanomolar levels. Sensing of amylin, an important protein for pancreatic function, was performed with polyclonal and monoclonal antibodies. The measured data demonstrates the difference in sensitivity to the two types of antibodies, and titration experiments establish the sensitivity of the sensor. Further experiments demonstrate that the sensor can be regenerated and then reused.

  13. Adaptive wavefront sensor based on the Talbot phenomenon.

    PubMed

    Podanchuk, Dmytro V; Goloborodko, Andrey A; Kotov, Myhailo M; Kovalenko, Andrey V; Kurashov, Vitalij N; Dan'ko, Volodymyr P

    2016-04-20

    A new adaptive method of wavefront sensing is proposed and demonstrated. The method is based on the Talbot self-imaging effect, which is observed in an illuminating light beam with strong second-order aberration. Compensation of defocus and astigmatism is achieved with an appropriate choice of size of the rectangular unit cell of the diffraction grating, which is performed iteratively. A liquid-crystal spatial light modulator is used for this purpose. Self-imaging of rectangular grating in the astigmatic light beam is demonstrated experimentally. High-order aberrations are detected with respect to the compensated second-order aberration. The comparative results of wavefront sensing with a Shack-Hartmann sensor and the proposed sensor are adduced. PMID:27140122

  14. An Optical Fibre-Based Sensor for Respiratory Monitoring

    PubMed Central

    Krehel, Marek; Schmid, Michel; Rossi, René M.; Boesel, Luciano F.; Bona, Gian-Luca; Scherer, Lukas J.

    2014-01-01

    In this paper, a textile-based respiratory sensing system is presented. Highly flexible polymeric optical fibres (POFs) that react to applied pressure were integrated into a carrier fabric to form a wearable sensing system. After the evaluation of different optical fibres, different setups were compared. To demonstrate the feasibility of such a wearable sensor, the setup featuring the best performance was placed on the human torso, and thus it was possible to measure the respiratory rate. Furthermore, we show that such a wearable system enables to keep track of the way of breathing (diaphragmatic, upper costal and mixed) when the sensor is placed at different positions of the torso. A comparison of the results with the output of some commercial respiratory measurements devices confirmed the utility of such a monitoring device. PMID:25051033

  15. Activity-based intelligence tipping and cueing using polarimetric sensors

    NASA Astrophysics Data System (ADS)

    Lewis, Christian M.; Messinger, David; Gartley, Michael G.

    2014-05-01

    Activity Based Intelligence (ABI) is the derivation of information from the composite of a series of individual actions being recorded over a period of time. Due to its temporal nature, ABI is usually developed from Motion Imagery (MI) or Full Motion Video (FMV) taken of a given scene. One of today's common issues is sifting through such large volumes of temporal data. Here we propose using a technique known as tipping an cueing to alleviate the need to manually sift through said data. Being able to tip the analysts or automated algorithm towards a particular person or object in the data is useful in reducing search time. We propose using a polarimetric sensor to identify objects of interest, in a scene where their signature would be unusual. Once identified, this data will be used to cue a FMV RGB sensor to track the object and determine the activities being executed by the person bringing the object into the scene.

  16. Monitoring methionine sulfoxide with stereospecific mechanism-based fluorescent sensors

    PubMed Central

    Tarrago, Lionel; Péterfi, Zalán; Lee, Byung Cheon; Michel, Thomas; Gladyshev, Vadim N.

    2015-01-01

    Methionine can be reversibly oxidized to methionine sulfoxide (MetO) under physiological and pathophysiological conditions, but its use as a redox marker suffers from the lack of tools to detect and quantify MetO within cells. In this work, we created a pair of complementary stereospecific genetically-encoded mechanism-based ratiometric fluorescent sensors of MetO by inserting a circularly yellow fluorescent protein between yeast methionine sulfoxide reductases and thioredoxins. The two sensors, named MetSOx and MetROx for their ability to detect S and R-forms of MetO, respectively, were utilized for targeted analysis of protein oxidation, regulation and repair, as well as for monitoring MetO in bacterial and mammalian cells, analyzing compartment-specific changes in MetO, and examining responses to physiological stimuli. PMID:25799144

  17. Pyrolyzed-parylene based sensors and method of manufacture

    NASA Technical Reports Server (NTRS)

    Tai, Yu-Chong (Inventor); Liger, Matthieu (Inventor); Miserendino, Scott (Inventor); Konishi, Satoshi (Inventor)

    2007-01-01

    A method (and resulting structure) for fabricating a sensing device. The method includes providing a substrate comprising a surface region and forming an insulating material overlying the surface region. The method also includes forming a film of carbon based material overlying the insulating material and treating to the film of carbon based material to pyrolyzed the carbon based material to cause formation of a film of substantially carbon based material having a resistivity ranging within a predetermined range. The method also provides at least a portion of the pyrolyzed carbon based material in a sensor application and uses the portion of the pyrolyzed carbon based material in the sensing application. In a specific embodiment, the sensing application is selected from chemical, humidity, piezoelectric, radiation, mechanical strain or temperature.

  18. Design and characterization of integrated-optic-based chemical sensors

    NASA Astrophysics Data System (ADS)

    Beregovskii, Iouri

    A novel line of integrated-optic-based chemical sensors was developed. The sensors are based on modification of the optical cavity of a single-mode semiconductor distributed Bragg reflector (DBR) laser. A sensitive layer changes its refractive index in presence of a specific chemical, thus changing the effective refractive index of the section and the optical length of the cavity. This results in laser frequency shift measured either directly or by heterodyne detection using a reference laser as the second source. It is shown that DBR-laser-based sensors can achieve in principle a much higher sensitivity than passive sensors, such as Mach- Zehnder interferometers, due to the narrow linewidth of DBR lasers. The theory of DBR-laser-based sensors is described. It allows optimizing the sensitive section length and field confinement in the sensitive layer for the lowest detection limit. The optimum parameters depend on cavity losses and absorption of the sensitive material. Numerical modeling shows a wide acceptable range of sensitive section parameters for low-loss materials, while for higher-loss materials this range becomes much narrower. Narrow-linewidth DBR lasers are required for high sensitivity. In this respect, sol-gel waveguides with and without Bragg grating were incorporated in the DBR laser scheme. Single-mode operation of DBR lasers with sol-gel waveguide gratings was demonstrated for the first time, with 34-dB side mode suppression and a short-term linewidth of 150 to 500 kHz. A 3-section configuration with sol-gel waveguides and fiber grating showed 28-dB side mode suppression and a short-term linewidth of 600 kHz. Chemical sensing was performed with fiber grating, sol- gel waveguide grating, and 3-section DBR lasers. The first two types showed frequency shift of over 130 MHz in the presence of acetone vapors, and reversibility within experimental errors. The 3-section scheme showed significant dispersion of response and lack of reversibility due to

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

    PubMed

    Bulbul, Ashrafuzzaman; Kim, Hanseup

    2015-01-01

    We report a new proof-of-concept bubble-based gas sensor for a gas chromatography system, which utilizes the unique relationship between the diameters of the produced bubbles with the gas types and mixture ratios as a sensing element. The bubble-based gas sensor consists of gas and liquid channels as well as a nozzle to produce gas bubbles through a micro-structure. It utilizes custom-developed software and an optical camera to statistically analyze the diameters of the produced bubbles in flow. The fabricated gas sensor showed that five types of gases (CO2, He, H2, N2, and CH4) produced (1) unique volumes of 0.44, 0.74, 1.03, 1.28, and 1.42 nL (0%, 68%, 134%, 191%, and 223% higher than that of CO2) and (2) characteristic linear expansion coefficients (slope) of 1.38, 2.93, 3.45, 5.06, and 5.44 nL/(kPa (μL s(-1))(-1)). The gas sensor also demonstrated that (3) different gas mixture ratios of CO2 : N2 (100 : 0, 80 : 20, 50 : 50, 20 : 80 and 0 : 100) generated characteristic bubble diameters of 48.95, 77.99, 71.00, 78.53 and 99.50 μm, resulting in a linear coefficient of 10.26 μm (μL s(-1))(-1). It (4) successfully identified an injection (0.01 μL) of pentane (C5) into a continuous carrier gas stream of helium (He) by monitoring bubble diameters and creating a chromatogram and demonstrated (5) the output stability within only 5.60% variation in 67 tests over a month. PMID:25350655

  20. CO responses of sensors based on cerium oxide thick films prepared from clustered spherical nanoparticles.

    PubMed

    Izu, Noriya; Matsubara, Ichiro; Itoh, Toshio; Akamatsu, Takafumi; Shin, Woosuck

    2013-01-01

    Various types of CO sensors based on cerium oxide (ceria) have been reported recently. It has also been reported that the response speed of CO sensors fabricated from porous ceria thick films comprising nanoparticles is extremely high. However, the response value of such sensors is not suitably high. In this study, we investigated methods of improving the response values of CO sensors based on ceria and prepared gas sensors from core-shell ceria polymer hybrid nanoparticles. These hybrid nanoparticles have been reported to have a unique structure: The core consists of a cluster of ceria crystallites several nanometers in size. We compared the characteristics of the sensors based on thick films prepared from core-shell nanoparticles with those of sensors based on thick films prepared from conventionally used precipitated nanoparticles. The sensors prepared from the core-shell nanoparticles exhibited a resistance that was ten times greater than that of the sensors prepared from the precipitated nanoparticles. The response values of the gas sensors based on the core-shell nanoparticles also was higher than that of the sensors based on the precipitated nanoparticles. Finally, improvements in sensor response were also noticed after the addition of Au nanoparticles to the thick films used to fabricate the two types of sensors. PMID:23529123

  1. Graphene Electronic Device Based Biosensors and Chemical Sensors

    NASA Astrophysics Data System (ADS)

    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

  2. Heterogeneous Catalytic Conversion of Dry Syngas to Ethanol and Higher Alcohols on Cu-Based Catalysts

    SciTech Connect

    Gupta, Mayank; Smith, Miranda L.; Spivey, James J.

    2011-04-19

    Ethanol and higher alcohols have been identified as potential fuel additives or hydrogen carriers for use in fuel cells. One method of ethanol production is catalytic conversion of syngas (a mixture of CO, H₂, CO₂, and H₂O), derived from biomass, coal, or natural gas. Thermodynamics of CO hydrogenation shows that ethanol is favored as the sole product at conditions of practical interest, but if methane is allowed as product in this analysis, essentially no ethanol is formed at equilibrium. The kinetics of ethanol formation must therefore be maximized. Although rhodium-based catalysts give C{sup 2+} oxygenates with high selectivity, their prohibitive cost has spurred research on less expensive copper-based alternatives. Copper-based catalysts require an optimum amount of promoter to suppress undesired reactions and maximize the yields of ethanol and higher alcohols. Common promoters include alkali, transition metals and their oxides, and rare earth oxides. Careful selection of operating variables is also necessary to achieve the desired activity and selectivity. This review describes the effects of promoters, supports, and operating conditions on the performance of copper-based catalysts for conversion of dry syngas to ethanol and higher alcohols. Proposed mechanisms from the literature for ethanol and higher-alcohol synthesis are outlined.

  3. Predicting Perceptions of Date Rape Based on Individual Beliefs and Female Alcohol Consumption.

    ERIC Educational Resources Information Center

    Osman, Suzanne L.; Davis, Clive M.

    1999-01-01

    Investigates whether female alcohol consumption predicts perceptions of date rape based on two personality measures administered to 290 undergraduates. Results indicate that a stronger belief in token resistance to sex was related to weaker perceptions of rape. As hypothesized, participants scoring higher on sex-role stereotyping perceived fewer…

  4. Mediators of Telephone-Based Continuing Care for Alcohol and Cocaine Dependence

    ERIC Educational Resources Information Center

    Mensinger, Janell Lynn; Lynch, Kevin G.; Tenhave, Thomas R.; McKay, James R.

    2007-01-01

    A previous randomized trial with 224 alcohol and/or cocaine addicts who had completed an initial phase of treatment indicated that 12 weeks of telephone-based continuing care yielded higher abstinence rates over 24 months than did group counseling continuing care. The current study examined mediators of this treatment effect. Results suggested…

  5. Development of an Adolescent Alcohol Misuse Intervention Based on the Prototype Willingness Model: A Delphi Study

    ERIC Educational Resources Information Center

    Davies, Emma; Martin, Jilly; Foxcroft, David

    2016-01-01

    Purpose: The purpose of this paper is to report on the use of the Delphi method to gain expert feedback on the identification of behaviour change techniques (BCTs) and development of a novel intervention to reduce adolescent alcohol misuse, based on the Prototype Willingness Model (PWM) of health risk behaviour. Design/methodology/approach: Four…

  6. 75 FR 82069 - Ethyl Alcohol for Fuel Use: Determination of the Base Quantity of Imports

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-29

    ... March 21, 1990 (55 FR 10512), and published its most recent previous determination for the 2010 amount in the Federal Register of December 23, 2009 (74 FR 68282). The Commission uses official statistics... COMMISSION Ethyl Alcohol for Fuel Use: Determination of the Base Quantity of Imports AGENCY: United...

  7. 76 FR 82320 - Ethyl Alcohol for Fuel Use: Determination of the Base Quantity of Imports

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-30

    ... its notice instituting this investigation in the Federal Register of March 21, 1990 (55 FR 10512), and..., 2010 (75 FR 82069). By order of the Commission. James R. Holbein, Secretary. BILLING CODE 7020-02-P ... COMMISSION Ethyl Alcohol for Fuel Use: Determination of the Base Quantity of Imports AGENCY: United...

  8. FOAMED ARTICLES BASED ON POTATO STARCH, CORN AND WHEAT FIBRE, AND POLY(VINYL ALCOHOL)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Continued research cooperation between USDA Laboratories (USA) and the University of Pisa, Italy, has yielded several composites based on blends of poly(vinyl alcohol) (PVA) and either corn or wheat fibres, co-product of the corn-wheat wet-milling process. Foam trays were prepared by baking the blen...

  9. Sensors for the detection of land-based munitions. Technical report

    SciTech Connect

    Healey, A.J.; Webber, W.T.

    1995-09-18

    This report provides a summary of current land.based munition detection sensor development. Sensors are categorized based upon the principle of their operation: electromagnetic, conductive, mechanical, optical, acoustic, and chemical. Each category is subdivided into particular operational sensor types. Theory of operation for each particular sensor type is provided, as well as a discussion of advantages and disadvantages of each. A discussion of sensor performance is included. The final section of the report is a survey of commercially available munition detection sensors along with comments concerning their performance.

  10. Intensity-modulated optical fiber sensors based on chirped-fiber Bragg gratings

    NASA Astrophysics Data System (ADS)

    Dong, Xinyong

    2011-09-01

    Intensity-modulated fiber Bragg grating (FBG) sensors, compared with normal wavelength-encoding FBG sensors, can reduce the cost of sensor system significantly by using cost-efficient optical power detection devices, instead of expensive wavelength measurement instruments. Chirped-FBG (CFBG) based intensity-modulated sensors show potential applications in various sensing areas due to their many advantages, including inherent independence of temperature, high measurement speed, and low cost, in addition to the merits of all fiber-optic sensors. This paper theoretically studies the sensing principle of CFBG-based intensity-modulated sensors and briefly reviews their recent progress in measurement of displacement, acceleration, and tilt angle.

  11. Optical Sensors Based on Single Arm Thin Film Waveguide Interferometer

    NASA Technical Reports Server (NTRS)

    Sarkisov, S. S.; Diggs, D.; Curley, M.; Adamovsky, Grigory (Technical Monitor)

    2001-01-01

    Single-arm double-mode double-order optical waveguide interferometer utilizes interference between two propagating modes of different orders. Sensing effect results from the change in propagation conditions of the modes caused by the environment. The waveguide is made as an open asymmetric slab structure containing a dye-doped polymer film onto a fused quartz substrate. It is more sensitive to the change of environment than its conventional polarimetric analog using orthogonal modes (TE and TM) of the same order. The sensor still preserves the option of operating in polarimetric regime using a variety of mode combinations such as TE(sub 0)/TM(sub 0) (conventional), TE(sub 0)/TM(sub 1), TE(sub 1)/TM(sub 0), or TE(sub 1)/TM(sub 1) but can also work in nonpolarimetric regime using combinations TE(sub 0)/TM(sub 1) or TE(sub 0)/TM(sub 1). Utilization of different mode combinations simultaneously makes the device more versatile. Application of the sensor to gas sensing is based on doping polymer film with an organic indicator dye sensitive to a particular gas. Change of optical absorption spectrum of the dye caused by the gaseous pollutant results change of the reactive index of the dye-doped polymer film that can be detected by the sensor. As an indicator dyes, we utilize Bromocresol Purple doped into polymer poly(methyl) methacrylate, which shows a reversible growth of the absorption peak neat 600 nm after exposure to wet ammonia. We have built a breadboard prototype of the sensor with He-Ne laser as a light source and with a single mode fiber input and a multimode fiber output. The prototype showed sensitivity to temperature change of the order of 2 C per one full oscillation of the signal. The sensitivity of the sensor to the presence of wet ammonia is 200 ppm per one full oscillation of the signal. The further improvements include switching to a longer wavelength laser source (750-nm semiconductor laser), substitution of poly(methyl) methacrylate with hydrophilic

  12. SSL: Signal Similarity-Based Localization for Ocean Sensor Networks

    PubMed Central

    Chen, Pengpeng; Ma, Honglu; Gao, Shouwan; Huang, Yan

    2015-01-01

    Nowadays, wireless sensor networks are often deployed on the sea surface for ocean scientific monitoring. One of the important challenges is to localize the nodes’ positions. Existing localization schemes can be roughly divided into two types: range-based and range-free. The range-based localization approaches heavily depend on extra hardware capabilities, while range-free ones often suffer from poor accuracy and low scalability, far from the practical ocean monitoring applications. In response to the above limitations, this paper proposes a novel signal similarity-based localization (SSL) technology, which localizes the nodes’ positions by fully utilizing the similarity of received signal strength and the open-air characteristics of the sea surface. In the localization process, we first estimate the relative distance between neighboring nodes through comparing the similarity of received signal strength and then calculate the relative distance for non-neighboring nodes with the shortest path algorithm. After that, the nodes’ relative relation map of the whole network can be obtained. Given at least three anchors, the physical locations of nodes can be finally determined based on the multi-dimensional scaling (MDS) technology. The design is evaluated by two types of ocean experiments: a zonal network and a non-regular network using 28 nodes. Results show that the proposed design improves the localization accuracy compared to typical connectivity-based approaches and also confirm its effectiveness for large-scale ocean sensor networks. PMID:26610520

  13. SSL: Signal Similarity-Based Localization for Ocean Sensor Networks.

    PubMed

    Chen, Pengpeng; Ma, Honglu; Gao, Shouwan; Huang, Yan

    2015-01-01

    Nowadays, wireless sensor networks are often deployed on the sea surface for ocean scientific monitoring. One of the important challenges is to localize the nodes' positions. Existing localization schemes can be roughly divided into two types: range-based and range-free. The range-based localization approaches heavily depend on extra hardware capabilities, while range-free ones often suffer from poor accuracy and low scalability, far from the practical ocean monitoring applications. In response to the above limitations, this paper proposes a novel signal similarity-based localization (SSL) technology, which localizes the nodes' positions by fully utilizing the similarity of received signal strength and the open-air characteristics of the sea surface. In the localization process, we first estimate the relative distance between neighboring nodes through comparing the similarity of received signal strength and then calculate the relative distance for non-neighboring nodes with the shortest path algorithm. After that, the nodes' relative relation map of the whole network can be obtained. Given at least three anchors, the physical locations of nodes can be finally determined based on the multi-dimensional scaling (MDS) technology. The design is evaluated by two types of ocean experiments: a zonal network and a non-regular network using 28 nodes. Results show that the proposed design improves the localization accuracy compared to typical connectivity-based approaches and also confirm its effectiveness for large-scale ocean sensor networks. PMID:26610520

  14. An International Disaster Management SensorWeb Consisting of Space-based and Insitu Sensors

    NASA Astrophysics Data System (ADS)

    Mandl, D.; Frye, S. W.; Policelli, F. S.; Cappelaere, P. G.

    2009-12-01

    For the past year, NASA along with partners consisting of the United Nations Space-based Information for Disaster and Emergency Response (UN-SPIDER) office, the Canadian Space Agency, the Ukraine Space Research Institute (SRI), Taiwan National Space Program Office (NSPO) and in conjunction with the Committee on Earth Observing Satellite (CEOS) Working Group on Information Systems and Services (WGISS) have been conducting a pilot project to automate the process of obtaining sensor data for the purpose of flood management and emergency response. This includes experimenting with flood prediction models based on numerous meteorological satellites and a global hydrological model and then automatically triggering follow up high resolution satellite imagery with rapid delivery of data products. This presentation will provide a overview of the effort, recent accomplishments and future plans.

  15. Is my drinking a problem? A community-based alcohol intervention programme post-Haiyan in Tacloban City

    PubMed Central

    Czaicki, Adam Edward; Fabrigas, Gloria; Hall, Julie Lyn

    2015-01-01

    Problem Evidence on alcohol use following disasters is scarce. After Typhoon Haiyan in the Philippines we wanted to determine whether there were alcohol-related problems among the disaster survivors and to strengthen the appropriate local health service support in Tacloban City. Context Tacloban City is a highly urbanized city that was one of the areas worst hit by Typhoon Haiyan. Prior to Haiyan there was very little support for people with alcohol problems, and the rehabilitation facility was located about 40 km away. Action A pilot community-based alcohol intervention programme was conducted that included: assessment of the extent of alcohol problems in the community and health-care workers baseline knowledge and skills; training of health-care workers on primary care alcohol intervention provision; and community outreach with post-training supervision. Outcome The alcohol screening found 26 (22%) of those attending health care facilities would benefit from some form of alcohol intervention. Health-care workers knowledge on basic alcohol intervention was low. This was strengthened during the training, and at outreach clinics the trained health-care workers were able to identify people with alcohol problems and provide them with treatment plans. Lessons learnt We learnt that there was a problem with alcohol in Tacloban City and that it was possible to run an alcohol intervention programme in the community using minimal resources. Addressing alcohol-related issues in the community is an important public health intervention. While there is a need for policies and guidelines at the national level, a community-based intervention is possible to establish with referral mechanism to specialized care. Training modules for such programs can be further developed and institutionalized. PMID:26767145

  16. An information-based approach to decentralized multiplatform sensor management

    NASA Astrophysics Data System (ADS)

    Kreucher, Christopher M.; Kastella, Keith D.; Wegrzyn, John W.; Rickenbach, Brent L.

    2006-05-01

    This paper describes a decentralized low communication approach to multi-platform sensor management. The method is based on a physicomimetic relaxation to a joint information theoretic optimization, which inherits the benefits of information theoretic scheduling while maintaining tractability. The method uses only limited message passing, only neighboring nodes communicate, and each node makes its own sensor management decisions. We show by simulation that the method allows a network of sensor nodes to automatically self organize and perform a global task. In the model problem, a group of unmanned aerial vehicles (UAVs) hover above a ground surveillance region. An initially unknown number of moving ground targets inhabit the region. Each UAV is capable of making noisy measurements of the patch of ground directly below, which provide evidence as to the presence or absence of targets in that sub-region. The goal of the network is to determine the number of targets and their individual states (positions and velocities) in the entire surveillance region through repeated interrogation by the individual nodes. As the individual nodes can only see a small portion of the ground, they must move in a manner that is both responsive to measurements and coordinated with other nodes.

  17. Technology towards a SAW based phononic crystal sensor

    NASA Astrophysics Data System (ADS)

    Schmidt, Marc-Peter; Oseev, Aleksandr; Lucklum, Ralf; Hirsch, Soeren

    2015-05-01

    Phononic crystals (PnC) with a specifically designed defect have been recently introduced as novel sensor platform. Those sensors feature a band gap covering the typical input span of the measurand as well as a narrow transmission peak within the band gap where the frequency of maximum transmission is governed by the measurand. This innovative approach has been applied for determination of compounds in liquids [1]. Improvement of sensitivity requires higher probing frequencies around 100 MHz and above. In this range surface acoustic wave devices (SAW) provide a promising basis for PnC based microsensors [2]. The respective feature size of the PnC SAW sensor has dimensions in the range of 100 μm and below. Whereas those dimensions are state of the art for common MEMS materials, etching of holes and cavities in piezoelectric materials having an aspect ratio diameter/depth is challenging. In this contribution we describe an improved technological process to manufacture considerably deep and uniform phononic crystal structures inside of SAW substrates.

  18. A magnonic gas sensor based on magnetic nanoparticles.

    PubMed

    Matatagui, D; Kolokoltsev, O V; Qureshi, N; Mejía-Uriarte, E V; Saniger, J M

    2015-06-01

    In this paper, we propose an innovative, simple and inexpensive gas sensor based on the variation in the magnetic properties of nanoparticles due to their interaction with gases. To measure the nanoparticle response a magnetostatic spin wave (MSW) tunable oscillator has been developed using an yttrium iron garnet (YIG) epitaxial thin film as a delay line (DL). The sensor has been prepared by coating a uniform layer of CuFe2O4 nanoparticles on the YIG film. The unperturbed frequency of the oscillator is determined by a bias magnetic field, which is applied parallel to the YIG film and perpendicularly to the wave propagation direction. In this device, the total bias magnetic field is the superposition of the field of a permanent magnet and the field associated with the layer of magnetic nanoparticles. The perturbation produced in the magnetic properties of the nanoparticle layer due to its interaction with gases induces a frequency shift in the oscillator, allowing the detection of low concentrations of gases. In order to demonstrate the ability of the sensor to detect gases, it has been tested with organic volatile compounds (VOCs) which have harmful effects on human health, such as dimethylformamide, isopropanol and ethanol, or the aromatic hydrocarbons like benzene, toluene and xylene more commonly known by its abbreviation (BTX). All of these were detected with high sensitivity, short response time, and good reproducibility. PMID:25952501

  19. A magnonic gas sensor based on magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Matatagui, D.; Kolokoltsev, O. V.; Qureshi, N.; Mejía-Uriarte, E. V.; Saniger, J. M.

    2015-05-01

    In this paper, we propose an innovative, simple and inexpensive gas sensor based on the variation in the magnetic properties of nanoparticles due to their interaction with gases. To measure the nanoparticle response a magnetostatic spin wave (MSW) tunable oscillator has been developed using an yttrium iron garnet (YIG) epitaxial thin film as a delay line (DL). The sensor has been prepared by coating a uniform layer of CuFe2O4 nanoparticles on the YIG film. The unperturbed frequency of the oscillator is determined by a bias magnetic field, which is applied parallel to the YIG film and perpendicularly to the wave propagation direction. In this device, the total bias magnetic field is the superposition of the field of a permanent magnet and the field associated with the layer of magnetic nanoparticles. The perturbation produced in the magnetic properties of the nanoparticle layer due to its interaction with gases induces a frequency shift in the oscillator, allowing the detection of low concentrations of gases. In order to demonstrate the ability of the sensor to detect gases, it has been tested with organic volatile compounds (VOCs) which have harmful effects on human health, such as dimethylformamide, isopropanol and ethanol, or the aromatic hydrocarbons like benzene, toluene and xylene more commonly known by its abbreviation (BTX). All of these were detected with high sensitivity, short response time, and good reproducibility.

  20. Case-Based Multi-Sensor Intrusion Detection

    NASA Astrophysics Data System (ADS)

    Schwartz, Daniel G.; Long, Jidong

    2009-08-01

    Multi-sensor intrusion detection systems (IDSs) combine the alerts raised by individual IDSs and possibly other kinds of devices such as firewalls and antivirus software. A critical issue in building a multi-sensor IDS is alert-correlation, i.e., determining which alerts are caused by the same attack. This paper explores a novel approach to alert correlation using case-based reasoning (CBR). Each case in the CBR system's library contains a pattern of alerts raised by some known attack type, together with the identity of the attack. Then during run time, the alert streams gleaned from the sensors are compared with the patterns in the cases, and a match indicates that the attack described by that case has occurred. For this purpose the design of a fast and accurate matching algorithm is imperative. Two such algorithms were explored: (i) the well-known Hungarian algorithm, and (ii) an order-preserving matching of our own device. Tests were conducted using the DARPA Grand Challenge Problem attack simulator. These showed that the both matching algorithms are effective in detecting attacks; but the Hungarian algorithm is inefficient; whereas the order-preserving one is very efficient, in fact runs in linear time.

  1. Integrated organic electronic based optochemical sensors using polarization filters

    SciTech Connect

    Kraker, Elke; Haase, Anja; Lamprecht, Bernhard; Jakopic, Georg; Konrad, Christian; Koestler, Stefan

    2008-01-21

    A compact, integrated photoluminescence based oxygen and pH sensor, utilizing an organic light emitting device (OLED) as the light source and an organic photodiode (OPD) as the detection unit, is described. The main challenge in such an integrated sensor is the suppression of the excitation light at the detector, which is typically by many orders of magnitude higher in intensity than the emitted fluorescence. In our approach, we refrain from utilizing edge filters which require narrow band excitation sources and dyes with an adequate large Stokes shift. We rather developed an integrated sensor concept relying on two polarizers to separate the emission and excitation light. One polarizer is located right after the OLED, while the other one, oriented at 90 deg. to the first, is placed in front of the OPD. The main advantage of this solution is that any combination of excitation and emission light is acceptable, even if the two signals overlap spectrally. This is especially important for the use of OLEDs as the excitation sources, as these devices typically exhibit a broad spectral emission.

  2. Sensor Based Engine Life Calculation: A Probabilistic Perspective

    NASA Technical Reports Server (NTRS)

    Guo, Ten-Huei; Chen, Philip

    2003-01-01

    It is generally known that an engine component will accumulate damage (life usage) during its lifetime of use in a harsh operating environment. The commonly used cycle count for engine component usage monitoring has an inherent range of uncertainty which can be overly costly or potentially less safe from an operational standpoint. With the advance of computer technology, engine operation modeling, and the understanding of damage accumulation physics, it is possible (and desirable) to use the available sensor information to make a more accurate assessment of engine component usage. This paper describes a probabilistic approach to quantify the effects of engine operating parameter uncertainties on the thermomechanical fatigue (TMF) life of a selected engine part. A closed-loop engine simulation with a TMF life model is used to calculate the life consumption of different mission cycles. A Monte Carlo simulation approach is used to generate the statistical life usage profile for different operating assumptions. The probabilities of failure of different operating conditions are compared to illustrate the importance of the engine component life calculation using sensor information. The results of this study clearly show that a sensor-based life cycle calculation can greatly reduce the risk of component failure as well as extend on-wing component life by avoiding unnecessary maintenance actions.

  3. Sensitive determination of citrinin based on molecular imprinted electrochemical sensor

    NASA Astrophysics Data System (ADS)

    Atar, Necip; Yola, Mehmet Lütfi; Eren, Tanju

    2016-01-01

    In this report, a novel molecular imprinted voltammetric sensor based on glassy carbon electrode (GCE) modified with platinum nanoparticles (PtNPs) involved in a polyoxometalate (H3PW12O40, POM) functionalized reduced graphene oxide (rGO) was prepared for the determination of citrinin (CIT). The developed surfaces were characterized by using scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) method. CIT imprinted GCE was prepared via electropolymerization process of 80.0 mM pyrrole as monomer in the presence of phosphate buffer solution (pH 6.0) containing 20.0 mM CIT. The linearity range and the detection limit of the developed method were calculated as 1.0 × 10-12-1.0 × 10-10 M and 2.0 × 10-13 M, respectively. In addition, the voltammetric sensor was applied to rye samples. The stability and selectivity of the voltammetric sensor were also reported.

  4. Organic electronics based pressure sensor towards intracranial pressure monitoring

    NASA Astrophysics Data System (ADS)

    Rai, Pratyush; Varadan, Vijay K.

    2010-04-01

    The intra-cranial space, which houses the brain, contains cerebrospinal fluid (CSF) that acts as a fluid suspension medium for the brain. The CSF is always in circulation, is secreted in the cranium and is drained out through ducts called epidural veins. The venous drainage system has inherent resistance to the flow. Pressure is developed inside the cranium, which is similar to a rigid compartment. Normally a pressure of 5-15 mm Hg, in excess of atmospheric pressure, is observed at different locations inside the cranium. Increase in Intra-Cranial Pressure (ICP) can be caused by change in CSF volume caused by cerebral tumors, meningitis, by edema of a head injury or diseases related to cerebral atrophy. Hence, efficient ways of monitoring ICP need to be developed. A sensor system and monitoring scheme has been discussed here. The system architecture consists of a membrane less piezoelectric pressure sensitive element, organic thin film transistor (OTFT) based signal transduction, and signal telemetry. The components were fabricated on flexible substrate and have been assembled using flip-chip packaging technology. Material science and fabrication processes, subjective to the device performance, have been discussed. Capability of the device in detecting pressure variation, within the ICP pressure range, is investigated and applicability of measurement scheme to medical conditions has been argued for. Also, applications of such a sensor-OTFT assembly for logic sensor switching and patient specific-secure monitoring system have been discussed.

  5. A flexoelectricity effect-based sensor for direct torque measurement

    NASA Astrophysics Data System (ADS)

    Zhang, Shuwen; Xu, Minglong; Liu, Kaiyuan; Shen, Shengping

    2015-12-01

    In this study, a direct torque sensor based on the flexoelectricity generated by un-polarized polyvinylidene fluoride (PVDF) via electromechanical coupling is developed as a novel torque measurement mechanism that does not require external electric power excitation. The sensing method is developed based on the shear strain gradient and the shear flexoelectric response of PVDF. A theoretical analysis is primarily presented for the design of the sensing structure. Then the structure of the PVDF sensing module is discussed and designed. The radius ratio of the sensing module is defined and then discussed according to the load, the strain gradient, the electrode area and the general electric charge output. The finite element method is used to analyze the mechanical properties of the designed PVDF sensing module. Then the theoretical sensitivity of the sensor is predicated as 0.9441 pC Nm-1. The experiment system setup is developed, and the sensing properties of the measurement mechanism are tested at frequencies of 0.5 Hz, 1 Hz, 1.5 Hz and 2 Hz using identical modules. The measurement range of the designed sensor is 0-1.68 Nm and the average sensitivity is measured as 0.8950 pC Nm-1. The experimental results agree well with the theoretically predicted results. These results prove that the torque sensing method based on un-polarized PVDF is suitable for measurement of dynamic torque loads with a flexoelectricity-based mechanism. When using this method, external electric power excitation of the sensing module is no longer required.

  6. Primary processes in heme-based sensor proteins.

    PubMed

    Liebl, Ursula; Lambry, Jean-Christophe; Vos, Marten H

    2013-09-01

    A wide and still rapidly increasing range of heme-based sensor proteins has been discovered over the last two decades. At the molecular level, these proteins function as bistable switches in which the catalytic activity of an enzymatic domain is altered mostly by binding or dissociation of small gaseous ligands (O2, NO or CO) to the heme in a sensor domain. The initial "signal" at the heme level is subsequently transmitted within the protein to the catalytic site, ultimately leading to adapted expression levels of specific proteins. Making use of the photolability of the heme-ligand bond that mimics thermal dissociation, early processes in this intra-protein signaling pathway can be followed using ultrafast optical spectroscopic techniques; they also occur on timescales accessible to molecular dynamics simulations. Experimental studies performed over the last decade on proteins including the sensors FixL (O2), CooA (CO) and soluble guanylate cyclase (NO) are reviewed with an emphasis on emerging general mechanisms. After heme-ligand bond breaking, the ligand can escape from the heme pocket and eventually from the protein, or rebind directly to the heme. Remarkably, in all sensor proteins the rebinding, specifically of the sensed ligand, is highly efficient. This "ligand trap" property possibly provides means to smoothen the effects of fast environmental fluctuations on the switching frequency. For 6-coordinate proteins, where exchange between an internal heme-bound residue and external gaseous ligands occurs, the study of early processes starting from the unliganded form indicates that mobility of the internal ligand may facilitate signal transfer. This article is part of a Special Issue entitled: Oxygen Binding and Sensing Proteins. PMID:23485911

  7. Examining Perceptions of a Smartphone-Based Intervention System for Alcohol Use Disorders

    PubMed Central

    Bacon, Samantha; King, Diane K.; Dulin, Patrick; Gonzalez, Vivian

    2014-01-01

    Abstract Background: This study presents results from qualitative interviews conducted with participants in a study on the effectiveness of the Location-Based Monitoring and Intervention System for Alcohol Use Disorders (LBMI-A), a smartphone-based, stand-alone intervention application (app) for adults with alcohol use disorders. Materials and Methods: Participants were provided an LBMI-A-enabled smartphone to use during a 6-week pilot study. The LBMI-A was composed of psychoeducational modules, assessment and feedback of alcohol use patterns, geographic high-risk location monitoring and alerts, and in vivo assessment and intervention for alcohol cravings and help with managing psychological distress. Semistructured interviews were conducted with all participants following 6 weeks of interacting with the LBMI-A app (n=26). Interviews explored user perceptions of the ease and utility of LBMI-A features, module helpfulness, barriers to use, and recommendations for improvements to the program. Researchers applied a systematic qualitative coding process to transcripts that included both a priori themes identified as important by the research team and new themes that emerged during the coding process. Results and Conclusions: Narrative analysis found the emergence of five main themes identified by LBMI-A users as the most helpful functions of the phone: (1) Awareness, (2) Accountability, (3) Skill Transference, (4) Tracking Progress, and (5) Prompts. These themes are explored, and implications of these findings for future smartphone-based interventions are discussed. PMID:25243480

  8. A PC-based software test for measuring alcohol and drug effects in human subjects.

    PubMed

    Mills, K C; Parkman, K M; Spruill, S E

    1996-12-01

    A new software-based visual search and divided-attention test of cognitive performance was developed and evaluated in an alcohol dose-response study with 24 human subjects aged 21-62 years. The test used language-free, color, graphic displays to represent the visuospatial demands of driving. Cognitive demands were increased over previous hardware-based tests, and the motor skills required for the test involved minimal eye movements and eye-hand coordination. Repeated performance on the test was evaluated with a latin-square design by using a placebo and two alcohol doses, low (0.48 g/kg/LBM) and moderate (0.72 g/kg/LBM). The data on 7 females and 17 males yielded significant falling and rising impairment effects coincident with moderate rising and falling breath alcohol levels (mean peak BrALs = 0.045 g/dl and 0.079 g/dl). None of the subjects reported eye-strain or psychomotor fatigue as compared with previous tests. The high sensitivity/variance relative to use in basic and applied research, and worksite fitness-for-duty testing, was discussed. The most distinct advantage of a software-based test that operates on readily available PCs is that it can be widely distributed to researchers with a common reference to compare a variety of alcohol and drug effects. PMID:8986207

  9. Conductive fiber-based ultrasensitive textile pressure sensor for wearable electronics.

    PubMed

    Lee, Jaehong; Kwon, Hyukho; Seo, Jungmok; Shin, Sera; Koo, Ja Hoon; Pang, Changhyun; Son, Seungbae; Kim, Jae Hyung; Jang, Yong Hoon; Kim, Dae Eun; Lee, Taeyoon

    2015-04-17

    A flexible and sensitive textile-based pressure sensor is developed using highly conductive fibers coated with dielectric rubber materials. The pressure sensor exhibits superior sensitivity, very fast response time, and high stability, compared with previous textile-based pressure sensors. By using a weaving method, the pressure sensor can be applied to make smart gloves and clothes that can control machines wirelessly as human-machine interfaces. PMID:25692572

  10. Hiding the Source Based on Limited Flooding for Sensor Networks.

    PubMed

    Chen, Juan; Lin, Zhengkui; Hu, Ying; Wang, Bailing

    2015-01-01

    Wireless sensor networks are widely used to monitor valuable objects such as rare animals or armies. Once an object is detected, the source, i.e., the sensor nearest to the object, generates and periodically sends a packet about the object to the base station. Since attackers can capture the object by localizing the source, many protocols have been proposed to protect source location. Instead of transmitting the packet to the base station directly, typical source location protection protocols first transmit packets randomly for a few hops to a phantom location, and then forward the packets to the base station. The problem with these protocols is that the generated phantom locations are usually not only near the true source but also close to each other. As a result, attackers can easily trace a route back to the source from the phantom locations. To address the above problem, we propose a new protocol for source location protection based on limited flooding, named SLP. Compared with existing protocols, SLP can generate phantom locations that are not only far away from the source, but also widely distributed. It improves source location security significantly with low communication cost. We further propose a protocol, namely SLP-E, to protect source location against more powerful attackers with wider fields of vision. The performance of our SLP and SLP-E are validated by both theoretical analysis and simulation results. PMID:26593923

  11. Hiding the Source Based on Limited Flooding for Sensor Networks

    PubMed Central

    Chen, Juan; Lin, Zhengkui; Hu, Ying; Wang, Bailing

    2015-01-01

    Wireless sensor networks are widely used to monitor valuable objects such as rare animals or armies. Once an object is detected, the source, i.e., the sensor nearest to the object, generates and periodically sends a packet about the object to the base station. Since attackers can capture the object by localizing the source, many protocols have been proposed to protect source location. Instead of transmitting the packet to the base station directly, typical source location protection protocols first transmit packets randomly for a few hops to a phantom location, and then forward the packets to the base station. The problem with these protocols is that the generated phantom locations are usually not only near the true source but also close to each other. As a result, attackers can easily trace a route back to the source from the phantom locations. To address the above problem, we propose a new protocol for source location protection based on limited flooding, named SLP. Compared with existing protocols, SLP can generate phantom locations that are not only far away from the source, but also widely distributed. It improves source location security significantly with low communication cost. We further propose a protocol, namely SLP-E, to protect source location against more powerful attackers with wider fields of vision. The performance of our SLP and SLP-E are validated by both theoretical analysis and simulation results. PMID:26593923

  12. Cross-calibration of Imaging Sensors using Model-based, SI-traceable Predictions of At-sensor Radiance

    NASA Technical Reports Server (NTRS)

    Thome, Kurtis; McCorkel, Joel

    2012-01-01

    Many inter-consistency efforts force empirical agreement between sensors viewing a source nearly coincident in time and geometry that ensures consistency between sensors rather than obtain an SI-traceable calibration with documented error budgets. The method described here provides interconsistency via absolute radiometric calibration with defensible error budget avoiding systematic errors through prediction of at-sensor radiance for a site viewed by multiple sensors but not necessarily viewed at coincident times. The method predicts spectral radiance over a given surface site for arbitrary view and illumination angles and for any date dominated by clear-sky conditions. The foundation is a model-based, SI-traceable prediction of at-sensor radiance over selected sites based on physical understanding of the surface and atmosphere. The calibration of the ground site will include spatial, spectral, and sunview geometric effects based on satellite and ground-based data. The result is an interconsistency of hyperspectral and multispectral sensors spanning spatial resolutions from meters to kilometers all relative to the surface site rather than a single sensor. The source-centric philosophy of calibrating the site inherently accounts for footprint size mismatch, spectral band mismatch, and temporal and spatial sampling effects. The method for characterizing the test site allows its use for SI-traceable calibration of any sensor that can view the calibrated test site. Interconsistency is obtained through the traceability and error budget rather than coincident views. Such an approach to inter-consistency provides better understanding of biases between sensors as well producing more accurate results with documented SI-traceability that reduces the need for overlapping data sets.

  13. On effectiveness of network sensor-based defense framework

    NASA Astrophysics Data System (ADS)

    Zhang, Difan; Zhang, Hanlin; Ge, Linqiang; Yu, Wei; Lu, Chao; Chen, Genshe; Pham, Khanh

    2012-06-01

    Cyber attacks are increasing in frequency, impact, and complexity, which demonstrate extensive network vulnerabilities with the potential for serious damage. Defending against cyber attacks calls for the distributed collaborative monitoring, detection, and mitigation. To this end, we develop a network sensor-based defense framework, with the aim of handling network security awareness, mitigation, and prediction. We implement the prototypical system and show its effectiveness on detecting known attacks, such as port-scanning and distributed denial-of-service (DDoS). Based on this framework, we also implement the statistical-based detection and sequential testing-based detection techniques and compare their respective detection performance. The future implementation of defensive algorithms can be provisioned in our proposed framework for combating cyber attacks.

  14. [Quantitative aspects of the percutaneous uptake of wool wax alcohols (cetyl alcohol) and paraffins (octadecane) from different ointment bases].

    PubMed

    Zesch, A; Bauer, E

    1985-01-01

    Since topical vehicles are partly responsible for the effects of active agents--both the wanted and the unwanted effects--attempt was made to obtain quantitative data on the possible penetration of cetyl alcohol contained in an aqueous hydrophilie cream (DAB 8) and in a wool fat alcohol ointment (lanoline) (DAB 8). Also the behaviour of the long-chained hydrocarbon, paraffin (octadecan), in these vehicles and in petrolatum (DAB 8) was studied. We found that the emulsifying agent in a W/O emulsion was detectable in the epidermis in low concentrations after 100 min, but the same agent in O/W emulsions only after 1000 min. It is, therefore, unlikely that cetyl alcohol penetrates the intact skin in allergicologically relevant concentrations. However, with diseased skin, a marked percutaneous absorption of cetyl alcohol, but not with paraffin, must be expected. PMID:3987517

  15. Localized surface plasmon resonance of silver nanoisland based glucose sensor

    NASA Astrophysics Data System (ADS)

    Venugopal, N.; Mitra, Anirban

    2013-06-01

    Study of optical properties of glucose is an attractive research topic for years. One of the goals is to develop a portable device for simple, reliable, cost effective and non-invasive monitoring of glucose in blood for diabetics. In this work, we study localized surface plasmon resonance (LSPR) of Ag nanoisland based glucose sensor. The progressive shift in LSPR caused by the various concentration of glucose from 2M to 10M has been investigated to monitor the sensing property. We correlate the redshift of LSPR is due to the change in refractive index of surrounding glucose medium. Preliminary results show that this may possibly reveal a new pathway for sensing glucose.

  16. Humidity and pressure sensor based on internal reflection.

    PubMed

    Domenegueti, J F M; Zilio, S C

    2014-03-10

    A low-cost humidity and pressure optical sensor, based on the internal reflection phenomenon, is presented. It takes advantage of the phase difference acquired by s- and p-polarized light undergoing internal reflection to generate an easily detectable minimum in the reflected profile, in a position corresponding to the critical angle. The apparatus presents good sensitivity to relative humidity changes above 70% and a response time below one second. The same device is also capable of measuring changes in pressure and can be used as a vacuum gauge between 1 and 1000 mbar. PMID:24663415

  17. Highly sensitive passive radio frequency identification based sensor systems

    NASA Astrophysics Data System (ADS)

    Wissenwasser, J.; Vellekoop, M.; Heer, R.

    2010-02-01

    A novel platform for sensor applications based on radio frequency (rf) identification technology, where passive tags are powered by the rf-field of a reader, is presented. The sophisticated energy harvesting system of the tag enables a blanking of the rf-field for a defined period, while supplying the tag electronics with a highly stable voltage and a power of 25 mW for 100 ms. During this time, span measurements can be performed without interferences of the rf-field. The presented tags work without batteries and are designed for impedance measurements on microbiological cell cultures under physiological relevant conditions as well as in harsh environments.

  18. Highly sensitive passive radio frequency identification based sensor systems.

    PubMed

    Wissenwasser, J; Vellekoop, M; Heer, R

    2010-02-01

    A novel platform for sensor applications based on radio frequency (rf) identification technology, where passive tags are powered by the rf-field of a reader, is presented. The sophisticated energy harvesting system of the tag enables a blanking of the rf-field for a defined period, while supplying the tag electronics with a highly stable voltage and a power of 25 mW for 100 ms. During this time, span measurements can be performed without interferences of the rf-field. The presented tags work without batteries and are designed for impedance measurements on microbiological cell cultures under physiological relevant conditions as well as in harsh environments. PMID:20192517

  19. Absorbance Based Light Emitting Diode Optical Sensors and Sensing Devices

    PubMed Central

    O'Toole, Martina; Diamond, Dermot

    2008-01-01

    The ever increasing demand for in situ monitoring of health, environment and security has created a need for reliable, miniaturised sensing devices. To achieve this, appropriate analytical devices are required that possess operating characteristics of reliability, low power consumption, low cost, autonomous operation capability and compatibility with wireless communications systems. The use of light emitting diodes (LEDs) as light sources is one strategy, which has been successfully applied in chemical sensing. This paper summarises the development and advancement of LED based chemical sensors and sensing devices in terms of their configuration and application, with the focus on transmittance and reflectance absorptiometric measurements.

  20. A Motor Speed Measurement System Based on Hall Sensor

    NASA Astrophysics Data System (ADS)

    Wang, Wen-Cheng

    The working principles of Hall sensor has been introduced in this paper. To the defects of traditional methods, it proposed the designing strategy of motor speed measurement system based on single chip microcontroller with integrated chip. The hardware circuits including power module, data processing module and data display module have been described and it focuses on the analysis speed measurement module. The speed data can be obtained through counting impulse signals and displayed on LED. Experience shows that the system have high stability, it can meet the needs of DC motor speed measurement.