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Sample records for nanotube sensing systems

  1. Smart materials: strain sensing and stress determination by means of nanotube sensing systems, composites, and devices

    Science.gov (United States)

    Barrera, Enrique V. (Inventor); Nagarajaiah, Satish (Inventor); Dharap, Prasad (Inventor); Zhiling, Li (Inventor); Kim, Jong Dae (Inventor)

    2010-01-01

    The present invention is directed toward devices comprising carbon nanotubes that are capable of detecting displacement, impact, stress, and/or strain in materials, methods of making such devices, methods for sensing/detecting/monitoring displacement, impact, stress, and/or strain via carbon nanotubes, and various applications for such methods and devices. The devices and methods of the present invention all rely on mechanically-induced electronic perturbations within the carbon nanotubes to detect and quantify such stress/strain. Such detection and quantification can rely on techniques which include, but are not limited to, electrical conductivity/conductance and/or resistivity/resistance detection/measurements, thermal conductivity detection/measurements, electroluminescence detection/measurements, photoluminescence detection/measurements, and combinations thereof. All such techniques rely on an understanding of how such properties change in response to mechanical stress and/or strain.

  2. A Wearable and Wireless Gas-Sensing System Using Flexible Polymer/Multi-Walled Carbon Nanotube Composite Films

    Directory of Open Access Journals (Sweden)

    Jin-Chern Chiou

    2017-09-01

    Full Text Available In this study, an integrated flexible gas sensor was developed based on a polymer/multi-walled carbon nanotube composite film by using Bluetooth wireless communication/interface technology. Polymer/multi-walled carbon nanotube composite films were deposited over a polyimide flexible substrate for building a gas sensor array by using a drop-casting method. Sensor response was acquired through interdigitated electrodes and multi-channel sensor boards, which were linked to a Bluetooth wireless transceiver. Additionally, a double-spiral-shaped heater was built into the backside of the gas sensor array as a thermostat to protect it from the influence of ambient temperature. Multi-channel sensing responses were read on a display screen via a smartphone application (app. The advantages of this system include light weight, low cost, highly integrated sensors, wireless telecommunication, and real-time functioning. Thus, it is a promising candidate for deployment in a wearable gas-sensing system used to study air pollution.

  3. Biosensors and Biofuel Cells based on Vertically Aligned Carbon Nanotubes for Integrated Energy Sensing, Generation, and Storage (SGS) Systems

    Science.gov (United States)

    Pandey, Archana; Prasad, Abhishek; Khin Yap, Yoke

    2010-03-01

    Diabetes is a growing health issue in the nation. Thus in-situ glucose sensors that can monitor the glucose level in our body are in high demand. Furthermore, it will be exciting if the excessive blood sugar can be converted into usable energy, and be stored in miniature batteries for applications. This will be the basis for an integrated energy sensing, generation, and storage (SGS) system in the future. Here we report the use of functionalized carbon nanotubes arrays as the glucose sensors as well as fuel cells that can convert glucose into energy. In principle, these devices can be integrated to detect excessive blood glucose and then convert the glucose into energy. They are also inline with our efforts on miniature 3D microbatteries using CNTs [1]. All these devices will be the basis for future SGS systems. Details of these results will be discussed in the meeting. [1] Wang et al., in 206^th Meeting of the Electrochemical Society, October 3-8, Honolulu, Hawaii (2004), Symposium Q1, abstract 1492. Y. K. Yap acknowledges supports from DARPA (DAAD17-03-C-0115), USDA (2007-35603-17740), and the Multi-Scale Technologies Institute (MuSTI) at MTU.

  4. Methods for Gas Sensing with Single-Walled Carbon Nanotubes

    Science.gov (United States)

    Kaul, Anupama B. (Inventor)

    2013-01-01

    Methods for gas sensing with single-walled carbon nanotubes are described. The methods comprise biasing at least one carbon nanotube and exposing to a gas environment to detect variation in temperature as an electrical response.

  5. Gas Composition Sensing Using Carbon Nanotube Arrays

    Science.gov (United States)

    Li, Jing; Meyyappan, Meyya

    2012-01-01

    This innovation is a lightweight, small sensor for inert gases that consumes a relatively small amount of power and provides measurements that are as accurate as conventional approaches. The sensing approach is based on generating an electrical discharge and measuring the specific gas breakdown voltage associated with each gas present in a sample. An array of carbon nanotubes (CNTs) in a substrate is connected to a variable-pulse voltage source. The CNT tips are spaced appropriately from the second electrode maintained at a constant voltage. A sequence of voltage pulses is applied and a pulse discharge breakdown threshold voltage is estimated for one or more gas components, from an analysis of the current-voltage characteristics. Each estimated pulse discharge breakdown threshold voltage is compared with known threshold voltages for candidate gas components to estimate whether at least one candidate gas component is present in the gas. The procedure can be repeated at higher pulse voltages to estimate a pulse discharge breakdown threshold voltage for a second component present in the gas. The CNTs in the gas sensor have a sharp (low radius of curvature) tip; they are preferably multi-wall carbon nanotubes (MWCNTs) or carbon nanofibers (CNFs), to generate high-strength electrical fields adjacent to the tips for breakdown of the gas components with lower voltage application and generation of high current. The sensor system can provide a high-sensitivity, low-power-consumption tool that is very specific for identification of one or more gas components. The sensor can be multiplexed to measure current from multiple CNT arrays for simultaneous detection of several gas components.

  6. Dual sensing-actuation artificial muscle based on polypyrrole-carbon nanotube composite

    Science.gov (United States)

    Schumacher, J.; Otero, Toribio F.; Pascual, Victor H.

    2017-04-01

    Dual sensing artificial muscles based on conducting polymer are faradaic motors driven by electrochemical reactions, which announce the development of proprioceptive devices. The applicability of different composites has been investigated with the aim to improve the performance. Addition of carbon nanotubes may reduce irreversible reactions. We present the testing of a dual sensing artificial muscle based on a conducting polymer and carbon nanotubes composite. Large bending motions (up to 127 degrees) in aqueous solution and simultaneously sensing abilities of the operation conditions are recorded. The sensing and actuation equations are derived for incorporation into a control system.

  7. Electrostatic sensing and electrochemistry with single carbon nanotubes

    NARCIS (Netherlands)

    Heller, I.

    2009-01-01

    This thesis describes the experimental study of devices based on single carbon nanotubes in the context of (bio)sensing in aqueous solutions. Carbon nanotubes are cylindrical molecules of sp2- carbon, about one nanometer in diameter and typically several micrometers long, which have semiconducting o

  8. Refractive-Index Sensing with Ultrathin Plasmonic Nanotubes

    DEFF Research Database (Denmark)

    Raza, Søren; Toscano, Giuseppe; Jauho, Antti-Pekka

    2013-01-01

    We study the refractive-index sensing properties of plasmonic nanotubes with a dielectric core and ultrathin metal shell. The few nanometer thin metal shell is described by both the usual Drude model and the nonlocal hydrodynamic model to investigate the effects of nonlocality. We derive an analy......We study the refractive-index sensing properties of plasmonic nanotubes with a dielectric core and ultrathin metal shell. The few nanometer thin metal shell is described by both the usual Drude model and the nonlocal hydrodynamic model to investigate the effects of nonlocality. We derive...... an analytical expression for the extinction cross section and show how sensing of the refractive index of the surrounding medium and the figure of merit are affected by the shape and size of the nanotubes. Comparison with other localized surface plasmon resonance sensors reveals that the nanotube exhibits...

  9. On the Direct Electron Transfer, Sensing, and Enzyme Activity in the Glucose Oxidase/Carbon Nanotubes System

    OpenAIRE

    2013-01-01

    The signal transduction and enzyme activity were investigated in biosensors based on the glucose oxidase (GOx) and carbon nanotubes (CNT) embedded in a bio-adhesive film of chitosan (CHIT). The voltammetric studies showed that, regardless of CHIT matrix, the GOx adsorbed on CNT yielding a pair of surface-confined current peaks at -0.48 V. The anodic peak did not increase in the presence of glucose in an O2-free solution indicating the lack of direct electron transfer (DET) between the enzymat...

  10. TiO2 Nanotubes: Recent Advances in Synthesis and Gas Sensing Properties

    Directory of Open Access Journals (Sweden)

    Giorgio Sberveglieri

    2013-10-01

    Full Text Available Synthesis—particularly by electrochemical anodization-, growth mechanism and chemical sensing properties of pure, doped and mixed titania tubular arrays are reviewed. The first part deals on how anodization parameters affect the size, shape and morphology of titania nanotubes. In the second part fabrication of sensing devices based on titania nanotubes is presented, together with their most notable gas sensing performances. Doping largely improves conductivity and enhances gas sensing performances of TiO2 nanotubes

  11. Nanotube-based Sensors and Systems for Outer Planetary Exploration

    Science.gov (United States)

    Noca, F.; Hunt, B. D.; Hoenk, M. E.; Choi, D.; Kowalczyk, R.; Williams, R.; Xu, J.; Koumoutsakos, P.

    2001-01-01

    Direct sensing and processing at the nanometer scale offer NASA the opportunity to expand its capabilities in deep space exploration, particularly for the search for signatures of life, the analysis of planetary oceans and atmospheres, and communications systems. Carbon nanotubes, with their unique mechanical, electrical, and radiation-tolerant properties, are a promising tool for this exploration. We are developing devices based on carbon nanotubes, including sensors, actuators, and oscillators. Additional information is contained in the original extended abstract.

  12. Printed Carbon Nanotube Electronics and Sensor Systems.

    Science.gov (United States)

    Chen, Kevin; Gao, Wei; Emaminejad, Sam; Kiriya, Daisuke; Ota, Hiroki; Nyein, Hnin Yin Yin; Takei, Kuniharu; Javey, Ali

    2016-06-01

    Printing technologies offer large-area, high-throughput production capabilities for electronics and sensors on mechanically flexible substrates that can conformally cover different surfaces. These capabilities enable a wide range of new applications such as low-cost disposable electronics for health monitoring and wearables, extremely large format electronic displays, interactive wallpapers, and sensing arrays. Solution-processed carbon nanotubes have been shown to be a promising candidate for such printing processes, offering stable devices with high performance. Here, recent progress made in printed carbon nanotube electronics is discussed in terms of materials, processing, devices, and applications. Research challenges and opportunities moving forward from processing and system-level integration points of view are also discussed for enabling practical applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Mobile Sensing Systems

    Directory of Open Access Journals (Sweden)

    Elsa Macias

    2013-12-01

    Full Text Available Rich-sensor smart phones have made possible the recent birth of the mobile sensing research area as part of ubiquitous sensing which integrates other areas such as wireless sensor networks and web sensing. There are several types of mobile sensing: individual, participatory, opportunistic, crowd, social, etc. The object of sensing can be people-centered or environment-centered. The sensing domain can be home, urban, vehicular… Currently there are barriers that limit the social acceptance of mobile sensing systems. Examples of social barriers are privacy concerns, restrictive laws in some countries and the absence of economic incentives that might encourage people to participate in a sensing campaign. Several technical barriers are phone energy savings and the variety of sensors and software for their management. Some existing surveys partially tackle the topic of mobile sensing systems. Published papers theoretically or partially solve the above barriers. We complete the above surveys with new works, review the barriers of mobile sensing systems and propose some ideas for efficiently implementing sensing, fusion, learning, security, privacy and energy saving for any type of mobile sensing system, and propose several realistic research challenges. The main objective is to reduce the learning curve in mobile sensing systems where the complexity is very high.

  14. Mobile Sensing Systems

    Science.gov (United States)

    Macias, Elsa; Suarez, Alvaro; Lloret, Jaime

    2013-01-01

    Rich-sensor smart phones have made possible the recent birth of the mobile sensing research area as part of ubiquitous sensing which integrates other areas such as wireless sensor networks and web sensing. There are several types of mobile sensing: individual, participatory, opportunistic, crowd, social, etc. The object of sensing can be people-centered or environment-centered. The sensing domain can be home, urban, vehicular… Currently there are barriers that limit the social acceptance of mobile sensing systems. Examples of social barriers are privacy concerns, restrictive laws in some countries and the absence of economic incentives that might encourage people to participate in a sensing campaign. Several technical barriers are phone energy savings and the variety of sensors and software for their management. Some existing surveys partially tackle the topic of mobile sensing systems. Published papers theoretically or partially solve the above barriers. We complete the above surveys with new works, review the barriers of mobile sensing systems and propose some ideas for efficiently implementing sensing, fusion, learning, security, privacy and energy saving for any type of mobile sensing system, and propose several realistic research challenges. The main objective is to reduce the learning curve in mobile sensing systems where the complexity is very high. PMID:24351637

  15. Hydrogen sensing characteristics from carbon nanotube field emissions

    Science.gov (United States)

    Dong, Changkun; Luo, Haijun; Cai, Jianqiu; Wang, Fuquan; Zhao, Yangyang; Li, Detian

    2016-03-01

    An innovative hydrogen sensing concept is demonstrated based on the field emission from multi-walled carbon nanotubes, where the low emission currents rise in proportion to hydrogen partial pressures above 10-9 Torr. Experimental and first principles studies reveal that the sensing mechanism is attributed to the effective work function reduction from dissociative hydrogen chemisorption. The embedded Ni catalyst would assist both the hydrogen dissociation and work function reduction. This technique is promising to build miniature low cost hydrogen sensors for multiple applications. This work is valuable for studies of nanocarbon-gas reaction mechanisms and the work function properties in adsorption related applications, including field emission, hydrogen storage, energy cells, and gas sensing.

  16. Carbon nanotube nanoweb-bioelectrode for highly selective dopamine sensing.

    Science.gov (United States)

    Zhao, Jie; Zhang, Weimin; Sherrell, Peter; Razal, Joselito M; Huang, Xu-Feng; Minett, Andrew I; Chen, Jun

    2012-01-01

    A highly sensitive and selective dopamine sensor was fabricated with the unique 3D carbon nanotube nanoweb (CNT-N) electrode. The as-synthesised CNT-N was modified by oxygen plasma to graft functional groups in order to increase selective electroactive sites at the CNT sidewalls. This electrode was characterized physically and electrochemically using HRSEM, Raman, FT-IR, and cyclic voltammetry (CV). Our investigations indicated that the O(2)-plasma treated CNT-N electrode could serve as a highly sensitive biosensor for the selective sensing of dopamine (DA, 1 μM to 20 μM) in the presence of ascorbic acid (AA, 1000 μM).

  17. Progress in Dielectrophoretic Assembly of Carbon Nanotubes for Sensing Application

    Directory of Open Access Journals (Sweden)

    Zhang Hong

    2016-01-01

    Full Text Available Carbon nanotubes (CNTs have shown their potential for broad applications in field effect transistor, field emission, interconnects, energy storage, biomedicine, and many others, due to their excellent electrical, thermal, and mechanical properties. One requirement for many of these applications is to assemble CNTs into designated devices. As a promising nanomanipulation method, dielectrophoresis (DEP has been widely applied to assemble CNTs in the fabrication of CNT-based nanodevices. This paper presents a brief review of the progress in CNT-based nanosensors and the application of DEP in device making. These sensors focus on the sensing of gases, temperature, bioparticles, light, pressure, stress, and strain.

  18. Fully integrated patterned carbon nanotube strain sensors on flexible sensing skin substrates for structural health monitoring

    Science.gov (United States)

    Burton, Andrew R.; Kurata, Masahiro; Nishino, Hiromichi; Lynch, Jerome P.

    2016-04-01

    New advances in nanotechnology and material processing is creating opportunities for the design and fabrication of a new generation of thin film sensors that can used to assess structural health. In particular, thin film sensors attached to large areas of the structure surface has the potential to provide spatially rich data on the performance and health of a structure. This study focuses on the development of a fully integrated strain sensor that is fabricated on a flexible substrate for potentially use in sensing skins. This is completed using a carbon nanotube-polymer composite material that is patterned on a flexible polyimide substrate using optical lithography. The piezoresistive carbon nanotube elements are integrated into a complete sensing system by patterning copper electrodes and integrating off-the-shelf electrical components on the flexible film for expanded functionality. This diverse material utilization is realized in a versatile process flow to illustrate a powerful toolbox for sensing severity, location, and failure mode of damage on structural components. The fully integrated patterned carbon nanotube strain sensor is tested on a quarter-scale, composite beam column connection. The results and implications for future structural damage detection are discussed.

  19. Carbon Nanotubes – Interactions with Biological Systems

    OpenAIRE

    Reis, Joana; Capela-Silva, Fernando; Potes, José; Fonseca, Alexandra; Oliveira, Mónica; Kanagaraj, Subramani; Marques, António Torres

    2011-01-01

    his book chapter discusses the prospective biomedical applications of carbon nanotubes based materials, the impact of carbon nanotubes properties in the interaction with biological systems. Protein adsorption, impact on cell viability and cytokine production are explored. Potential respiratory and dermal toxicity are reviewed, as the difficulties on studying the biological response. In face of recent studies, special attention is drawn upon promising orthopaedic use.

  20. Carbon nanotube based sensors and fluctuation enhanced sensing

    Energy Technology Data Exchange (ETDEWEB)

    Kukovecz, Akos; Konya, Zoltan; Haspel, Henrik; Mohl, Melinda; Sapi, Andras; Kiricsi, Imre [Department of Applied and Environmental Chemistry, University of Szeged (Hungary); Molnar, Daniel; Heszler, Peter [Research Group on Laser Physics of the Hungarian Academy of Sciences, University of Szeged (Hungary); Kordas, Krisztian; Maeklin, Jani; Halonen, Niina; Toth, Geza [Microelectronics and Materials Physics Laboratories, and EMPART Research Group of Infotech Oulu, University of Oulu (Finland); Gingl, Zoltan; Mingesz, Robert [Department of Experimental Physics, University of Szeged (Hungary); Moilanen, Hannu [Laserprobe LP Ltd., Oulu (Finland); Roth, Siegmar [Max Planck Institute for Solid State Research, Stuttgart (Germany); Vajtai, Robert; Ajayan, Pulickel M. [Department of Mechanical Engineering and Materials Science, Rice University, Houston, TX (United States); Pouillon, Yann; Rubio, Angel [Nano-Bio Spectroscopy Group y ETSF Scientific Development Centre, Dpto. Fisica de Materiales, Universidad del Pais Vasco, Centro de Fisica de Materiales CSIC-UPV/EHU-MPC y DIPC, San Sebastian (Spain)

    2010-04-15

    Drop-cast thin films of multi-walled carbon nanotubes are used as gas sensors in a four-probe measurement setup. The novelty of the approach is that the sensor information is extracted from the noise of the dc resistance data using Fluctuation Enhanced Sensing (FES). We investigate the effects of measurement duration, gate voltage and frequency window on the chemical selectivity of the MWCNT-FES sensor. The selectivity of the device is superior to those of conventional gas sensors, and preliminary experiments indicate that it may also be possible to extract quantitative information from the noise. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Aligned carbon nanotube thin films for DNA electrochemical sensing

    Energy Technology Data Exchange (ETDEWEB)

    Berti, F. [Department of Chemistry, University of Florence, Via della Lastruccia 3, Sesto Fiorentino, Firenze 50019 (Italy); Lozzi, L. [Department of Physics, University of L' Aquila, Coppito, L' Aquila 67100 (Italy); Palchetti, I. [Department of Chemistry, University of Florence, Via della Lastruccia 3, Sesto Fiorentino, Firenze 50019 (Italy); Santucci, S. [Department of Physics, University of L' Aquila, Coppito, L' Aquila 67100 (Italy); Marrazza, G. [Department of Chemistry, University of Florence, Via della Lastruccia 3, Sesto Fiorentino, Firenze 50019 (Italy)], E-mail: giovanna.marrazza@unifi.it

    2009-09-01

    Carbon nanotubes are interesting materials for DNA electrochemical sensing due to their unique electric properties: high surface area, fast heterogeneous electron transfer, and electrochemical stability. In this work aligned Carbon NanoTube (CNT) thin films were designed and tested as candidate platforms for DNA immobilization and for the development of an electrochemical genosensor. The films were prepared by Chemical Vapor Deposition (CVD) using acetylene and ammonia as precursor gases and nickel particles as catalyst. A preliminary electrochemical characterization was performed using cyclic voltammetry since, so far, these films have been used only for gas sensing. The surfaces were then covalently functionalized with a DNA oligonucleotide probe, complementary to the sequence of the most common inserts in the GMOs: the Promoter 35S. The genosensor format involved the immobilization of the probe onto the sensor surface, the hybridization with the target-sequence and the electrochemical detection of the duplex formation. Careful attention was paid to the probe immobilization conditions in order to minimize the signal due to non-specifically adsorbed sequences. For the detection of the hybridization event both label-free and enzyme-labelled methods were investigated. In case of the enzyme-labelled method a target concentration at nanomolar level can be easily detected, with a linear response from 50 nM to 200 nM, whereas the label-free method showed a linear response between 0.5 {mu}M and 10 {mu}M. The reproducibility was 11% and 20% with the enzyme-labelled method and the label-free method, respectively. The batch-to-batch reproducibility of the different sensors was also evaluated.

  2. A Single-Walled Carbon Nanotube Network Gas Sensing Device

    Directory of Open Access Journals (Sweden)

    I-Ju Teng

    2011-08-01

    Full Text Available The goal of this research was to develop a chemical gas sensing device based on single-walled carbon nanotube (SWCNT networks. The SWCNT networks are synthesized on Al2O3-deposted SiO2/Si substrates with 10 nm-thick Fe as the catalyst precursor layer using microwave plasma chemical vapor deposition (MPCVD. The development of interconnected SWCNT networks can be exploited to recognize the identities of different chemical gases by the strength of their particular surface adsorptive and desorptive responses to various types of chemical vapors. The physical responses on the surface of the SWCNT networks cause superficial changes in the electric charge that can be converted into electronic signals for identification. In this study, we tested NO2 and NH3 vapors at ppm levels at room temperature with our self-made gas sensing device, which was able to obtain responses to sensitivity changes with a concentration of 10 ppm for NO2 and 24 ppm for NH3.

  3. Selective functionalization of carbon nanotube tips allowing fabrication of new classes of nanoscale sensing and manipulation tools

    Science.gov (United States)

    Wade, Lawrence A. (Inventor); Shapiro, Ian R. (Inventor); Collier, Charles Patrick (Inventor); Esplandiu, Maria J. (Inventor); Bittner, Jr., Vern Garrett (Inventor); Giapis, Konstantinos P. (Inventor)

    2009-01-01

    Embodiments in accordance with the present invention relate to techniques for the growth and attachment of single wall carbon nanotubes (SWNT), facilitating their use as robust and well-characterized tools for AFM imaging and other applications. In accordance with one embodiment, SWNTs attached to an AFM tip can function as a structural scaffold for nanoscale device fabrication on a scanning probe. Such a probe can trigger, with nanometer precision, specific biochemical reactions or conformational changes in biological systems. The consequences of such triggering can be observed in real time by single-molecule fluorescence, electrical, and/or AFM sensing. Specific embodiments in accordance with the present invention utilize sensing and manipulation of individual molecules with carbon nanotubes, coupled with single-molecule fluorescence imaging, to allow observation of spectroscopic signals in response to mechanically induced molecular changes. Biological macromolecules such as proteins or DNA can be attached to nanotubes to create highly specific single-molecule probes for investigations of intermolecular dynamics, for assembling hybrid biological and nanoscale materials, or for developing molecular electronics. In one example, electrical wiring of single redox enzymes to carbon nanotube scanning probes allows observation and electrochemical control over single enzymatic reactions by monitoring fluorescence from a redox-active cofactor or the formation of fluorescent products. Enzymes ''nanowired'' to the tips of carbon nanotubes in accordance with embodiments of the present invention, may enable extremely sensitive probing of biological stimulus-response with high spatial resolution, including product-induced signal transduction.

  4. Superior selectivity and sensitivity of blue phosphorus nanotubes in gas sensing applications

    KAUST Repository

    Montes Muñoz, Enrique

    2017-05-23

    On the basis of first principles calculations, we study the adsorption of CO, CO2, NH3, NO, and NO2 molecules on armchair and zigzag blue phosphorus nanotubes. The nanotubes are found to surpass the gas sensing performance of other one-dimensional materials, in particular Si nanowires and carbon nanotubes, and two-dimensional materials, in particular graphene, phosphorene, and MoS2. Investigation of the energetics of the gas adsorption and induced charge transfers indicates that blue phosphorus nanotubes are highly sensitive to N-based molecules, in particular NO2, due to covalent bonding. The current–voltage characteristics of nanotubes connected to Au electrodes are derived by the non-equilibrium Green\\'s function formalism and used to quantitatively evaluate the change in resistivity upon gas adsorption. The observed selectivity and sensitivity properties make blue phosphorus nanotubes superior gas sensors for a wide range of applications.

  5. Carbon nanotube heat-exchange systems

    Science.gov (United States)

    Hendricks, Terry Joseph; Heben, Michael J.

    2008-11-11

    A carbon nanotube heat-exchange system (10) and method for producing the same. One embodiment of the carbon nanotube heat-exchange system (10) comprises a microchannel structure (24) having an inlet end (30) and an outlet end (32), the inlet end (30) providing a cooling fluid into the microchannel structure (24) and the outlet end (32) discharging the cooling fluid from the microchannel structure (24). At least one flow path (28) is defined in the microchannel structure (24), fluidically connecting the inlet end (30) to the outlet end (32) of the microchannel structure (24). A carbon nanotube structure (26) is provided in thermal contact with the microchannel structure (24), the carbon nanotube structure (26) receiving heat from the cooling fluid in the microchannel structure (24) and dissipating the heat into an external medium (19).

  6. Soluble organic nanotubes for catalytic systems

    Science.gov (United States)

    Xiong, Linfeng; Yang, Kunran; Zhang, Hui; Liao, Xiaojuan; Huang, Kun

    2016-03-01

    In this paper, we report a novel method for constructing a soluble organic nanotube supported catalyst system based on single-molecule templating of core-shell bottlebrush copolymers. Various organic or metal catalysts, such as sodium prop-2-yne-1-sulfonate (SPS), 1-(2-(prop-2-yn-1-yloxy)ethyl)-1H-imidazole (PEI) and Pd(OAc)2 were anchored onto the tube walls to functionalize the organic nanotubes via copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. Depending on the ‘confined effect’ and the accessible cavity microenvironments of tubular structures, the organic nanotube catalysts showed high catalytic efficiency and site-isolation features. We believe that the soluble organic nanotubes will be very useful for the development of high performance catalyst systems due to their high stability of support, facile functionalization and attractive textural properties.

  7. Carbon Nanotube Chemiresistor for Wireless pH Sensing

    Science.gov (United States)

    Gou, Pingping; Kraut, Nadine D.; Feigel, Ian M.; Bai, Hao; Morgan, Gregory J.; Chen, Yanan; Tang, Yifan; Bocan, Kara; Stachel, Joshua; Berger, Lee; Mickle, Marlin; Sejdić, Ervin; Star, Alexander

    2014-03-01

    The ability to accurately measure real-time pH fluctuations in-vivo could be highly advantageous. Early detection and potential prevention of bacteria colonization of surgical implants can be accomplished by monitoring associated acidosis. However, conventional glass membrane or ion-selective field-effect transistor (ISFET) pH sensing technologies both require a reference electrode which may suffer from leakage of electrolytes and potential contamination. Herein, we describe a solid-state sensor based on oxidized single-walled carbon nanotubes (ox-SWNTs) functionalized with the conductive polymer poly(1-aminoanthracene) (PAA). This device had a Nernstian response over a wide pH range (2-12) and retained sensitivity over 120 days. The sensor was also attached to a passively-powered radio-frequency identification (RFID) tag which transmits pH data through simulated skin. This battery-less, reference electrode free, wirelessly transmitting sensor platform shows potential for biomedical applications as an implantable sensor, adjacent to surgical implants detecting for infection.

  8. Electrical and VOC sensing properties of anatase and rutile TiO{sub 2} nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Sennik, Erdem [Gebze Institute of Technology, Department of Physics, Kocaeli (Turkey); Kilinc, Necmettin, E-mail: nkilinc@gyte.edu.tr [Gebze Institute of Technology, Department of Physics, Kocaeli (Turkey); Nigde University, Mechatronics Engineering Department, 51245 Nigde (Turkey); Ozturk, Zafer Ziya [Gebze Institute of Technology, Department of Physics, Kocaeli (Turkey); TÜBITAK-Marmara Research Center, Materials Institute, Kocaeli (Turkey)

    2014-12-15

    Graphical abstract: - Highlights: • TiO{sub 2} nanotubes fabricated by anodizing of Ti thin films in aqueous HF electrolytes. • TiO{sub 2} nanotubes annealed at 300 °C and 700 °C to obtain anatase and rutile phases. • Electrical, optical and VOC gas sensing properties of the nanotubes investigated. • Dc conduction mechanism can be explained with the thermally activated conduction. • The sensor response of anatase was higher than that of rutile for almost all VOC gases. - Abstract: The dc electrical and volatile organic compound (VOC) sensing properties of TiO{sub 2} nanotubes in both anatase and rutile phases were investigated. TiO{sub 2} nanotube arrays were obtained in aqueous HF (0.5 wt.%) electrolytes by anodizing of Ti thin films that deposited on quartz substrates using thermal evaporation. Anodization was performed at 10 V in aqueous HF at 0 °C. Then the fabricated TiO{sub 2} nanotubes were annealed at 300 °C and at 700 °C under dry air for 5 h to obtain anatase and rutile phases, respectively. The TiO{sub 2} nanotubes were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) as structural, and UV–vis spectrophotometer as optical. The current voltage characteristics of the nanotubes under dry air flow revealed that the conductivity of the sample with anatase phase was higher than that of the sample with rutile phase. The VOCs sensing properties of the nanotubes were investigated at 200 °C. It was found that the sensor response of anatase was higher than that of rutile for almost all VOC gases. On the other hand, the sensitivities of two sensors are the highest for isopropyl alcohol.

  9. Excellent ethanol sensing properties based on Er2O3-Fe2O3 nanotubes

    Institute of Scientific and Technical Information of China (English)

    刘唱白; 何滢; 王圣蕾

    2015-01-01

    In this work, pureα-Fe2O3 and Er2O3-Fe2O3 nanotubes were synthesized by a simple single-capillary electrospin-ning technology followed by calcination treatment. The morphologies and crystal structures of the as-prepared samples were characterized by scanning electron microscopy and x-ray diffraction, respectively. The gas-sensing properties of the as-prepared samples have been researched, and the result shows that the Er2O3-Fe2O3 nanotubes exhibit much better sen-sitivity to ethanol. The response value of Er2O3-Fe2O3 nanotubes to 10 ppm ethanol is 21 at the operating temperature 240◦, which is 14 times larger than that of pureα-Fe2O3 nanotubes (response value is 1.5). The ethanol sensing properties ofα-Fe2O3 nanotubes are remarkably enhanced by doping Er, and the lowest detection limit of Er2O3-Fe2O3 nanotubes is 300 ppb, to which the response value is about 2. The response and recovery times are about 4 s and 70 s to 10 ppm ethanol, respectively. In addition, the Er2O3-Fe2O3 nanotubes possess good selectivity and long-term stability.

  10. Sensing human physiological response using wearable carbon nanotube-based fabrics

    Science.gov (United States)

    Wang, Long; Loh, Kenneth J.; Koo, Helen S.

    2016-04-01

    Flexible and wearable sensors for human monitoring have received increased attention. Besides detecting motion and physical activity, measuring human vital signals (e.g., respiration rate and body temperature) provide rich data for assessing subjects' physiological or psychological condition. Instead of using conventional, bulky, sensing transducers, the objective of this study was to design and test a wearable, fabric-like sensing system. In particular, multi-walled carbon nanotube (MWCNT)-latex thin films of different MWCNT concentrations were first fabricated using spray coating. Freestanding MWCNT-latex films were then sandwiched between two layers of flexible fabric using iron-on adhesive to form the wearable sensor. Second, to characterize its strain sensing properties, the fabric sensors were subjected to uniaxial and cyclic tensile load tests, and they exhibited relatively stable electromechanical responses. Finally, the wearable sensors were placed on a human subject for monitoring simple motions and for validating their practical strain sensing performance. Overall, the wearable fabric sensor design exhibited advances such as flexibility, ease of fabrication, light weight, low cost, noninvasiveness, and user comfort.

  11. Deposition and characterization of carbon nanotubes (CNTS) based films for sensing applications

    Science.gov (United States)

    Dissanayake, Amila C.

    The advent of carbon nanotubes (CNTs) has opened up lot of novel applications because of their unique electrical and mechanical properties. CNTs are well known material for its exceptional electrical, mechanical, optical, thermal and chemical properties. A single-wall nanotube (SWNT) can be either semiconducting, metallic or semi-metallic, based on its chirality and diameter. SWNTs can be used in transistor device as active channels due to high electron mobility (~10000 cm2/(V s), electrical interconnects, nano-scale circuits, field-emission displays, light-emitting devices and thermal heat sinks due to low resistivity, high current density (~109A cm-2 ) and high thermal conductivity (~3500 W m-1). Further, their high Young's modulus and fracture stress is suitable for various sensing applications such as strain/pressure and use in chemical/biological sensors. This work mainly involves the deposition of CNT-based films following two different methods via a conventional microwave chemical vapor deposition (MWCVD) and spinning CNT-composites, and explored the possibility of using CNT-based films in strain gauge applications. Deposited films are characterized and analyzed for their structure, microstructure, composition and electrical properties. Rutherford Backscattering Spectrometry (RBS), X-ray Reflectivity (XRR), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM) and electrical impedance measurement techniques are used to characterize the films prepared by both the above mentioned methods. The synthesis/deposition process is improved based on the observed films properties. A carbon nanotube forest grown on the Si (100) substrate with Ni as a catalyst using CVD system shows an amorphous nature due to loss of catalytic activity of Ni nano-islands. XPS and RBS data show Ni nano-particles diffused into the Si substrate and surface layer of Ni particles turns out to nickel silicide. The

  12. Advances in NO2 sensing with individual single-walled carbon nanotube transistors

    Science.gov (United States)

    Muoth, Matthias; Roman, Cosmin; Haluska, Miroslav; Hierold, Christofer

    2014-01-01

    Summary The charge carrier transport in carbon nanotubes is highly sensitive to certain molecules attached to their surface. This property has generated interest for their application in sensing gases, chemicals and biomolecules. With over a decade of research, a clearer picture of the interactions between the carbon nanotube and its surroundings has been achieved. In this review, we intend to summarize the current knowledge on this topic, focusing not only on the effect of adsorbates but also the effect of dielectric charge traps on the electrical transport in single-walled carbon nanotube transistors that are to be used in sensing applications. Recently, contact-passivated, open-channel individual single-walled carbon nanotube field-effect transistors have been shown to be operational at room temperature with ultra-low power consumption. Sensor recovery within minutes through UV illumination or self-heating has been shown. Improvements in fabrication processes aimed at reducing the impact of charge traps have reduced the hysteresis, drift and low-frequency noise in carbon nanotube transistors. While open challenges such as large-scale fabrication, selectivity tuning and noise reduction still remain, these results demonstrate considerable progress in transforming the promise of carbon nanotube properties into functional ultra-low power, highly sensitive gas sensors. PMID:25551046

  13. Novel Carbon Nanotube-Based Nanostructures for High-Temperature Gas Sensing

    Energy Technology Data Exchange (ETDEWEB)

    Zhi Chen; Kozo Saito

    2008-08-31

    The primary objective of this research is to examine the feasibility of using vertically aligned multi-wall carbon nanotubes (MWCNTs) as a high temperature sensor material for fossil energy systems where reducing atmospheres are present. In the initial period of research, we fabricated capacitive sensors for hydrogen sensing using vertically aligned MWCNTs. We found that CNT itself is not sensitive to hydrogen. Moreover, with the help of Pd electrodes, hydrogen sensors based on CNTs are very sensitive and fast responsive. However, the Pd-based sensors can not withstand high temperature (T<200 C). In the last year, we successfully fabricated a hydrogen sensor based on an ultra-thin nanoporous titanium oxide (TiO{sub 2}) film supported by an AAO substrate, which can operate at 500 C with hydrogen concentrations in a range from 50 to 500 ppm.

  14. Novel self-sensing carbon nanotube-based composites for rehabilitation of structural steel members

    Science.gov (United States)

    Ahmed, Shafique; Doshi, Sagar; Schumacher, Thomas; Thostenson, Erik T.; McConnell, Jennifer

    2016-02-01

    Fatigue and fracture are among the most critical forms of damage in metal structures. Fatigue damage can initiate from microscopic defects (e.g., surface scratches, voids in welds, and internal defects) and initiate a crack. Under cyclic loading, these cracks can grow and reach a critical level to trigger fracture of the member which leads to compromised structural integrity and, in some cases, catastrophic failure of the entire structure. In our research, we are investigating a solution using carbon nanotube-based sensing composites, which have the potential to simultaneously rehabilitate and monitor fatigue-cracked structural members. These composites consist of a fiber-reinforced polymer (FRP) layer and a carbon nanotube-based sensing layer, which are integrated to form a novel structural self-sensing material. The sensing layer is composed of a non-woven aramid fabric that is coated with carbon nanotubes (CNT) to form an electrically conductive network that is extremely sensitive to detecting deformation as well as damage accumulation via changes in the resistance of the CNT network. In this paper, we introduce the sensing concept, describe the manufacturing of a model sensing prototype, and discuss a set of small-scale laboratory experiments to examine the load-carrying capacity and damage sensing response.

  15. The gas sensing properties of TiO2 nanotubes synthesized by hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    Yan Li Wang; Shun Tan; Jia Wang; Zhi Jin Tan; Qiu Xia Wu; Zheng Jiao; Ming Hong Wu

    2011-01-01

    In this paper, the TiO2 nanotubes were synthesized by hydrothermal method usinga 10 mol/LNaOH aqueous solution at 150 ℃. The structure of prepared materials was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM) and Brunauer-Emmett-Teller (BET). The prepared TiO2 nanotubes were used to prepare thick film gas sensors and the gas sensing properties to various gases were tested. Results show the prepared TiO2 nanotube gas sensors responses to ethanol under dry condition at 450 ℃. This could be attributed to the fact that it had high porous morphology and a higher pore volume, which can promote the diffusion of ethanol deep inside the films and improve the sensor response. Moreover, the gas sensor made with nanotubes exhibit high selective response towards ethanol gas compared with H2, CO, acetone.

  16. Studying Sensing-Based Systems

    DEFF Research Database (Denmark)

    Kjærgaard, Mikkel Baun

    2013-01-01

    Recent sensing-based systems involve a multitude of users, devices, and places. These types of systems challenge existing approaches for conducting valid system evaluations. Here, the author discusses such evaluation challenges and revisits existing system evaluation methodologies....

  17. Ultrathin gold nanowire-functionalized carbon nanotubes for hybrid molecular sensing.

    Science.gov (United States)

    Cui, Huizhong; Hong, Chenglin; Ying, Andrew; Yang, Xinmai; Ren, Shenqiang

    2013-09-24

    Carbon nanotubes (CNTs) have shown great potential as sensing component in the electrochemical field effect transistor and optical sensors, because of their extraordinary one-dimensional electronic structure, thermal conductivity, and tunable and stable near-infrared emission. However, the insolubility of CNTs due to strong van der Waals interactions limits their use in the field of nanotechnology. In this study, we demonstrate that noncovalent ultrathin gold nanowires functionalized multiwalled carbon nanotube (GNW-CNT) hybrid sensing agents show highly efficient and selective immune molecular sensing in electrochemical and near-infrared photoacoustic imaging methods. A detection limit of 0.01 ng/mL for the alpha-fetoprotein (AFP) antigen with high selectivity is shown. The extraordinary optical absorption, thermal, and electric conductivity of hybrid GNW-CNTs presented in this study could be an effective tactic to integrate imaging, sensing, and treatment functionalities.

  18. Fabrication of TiO2 Nanotube Thin Films and Their Gas Sensing Properties

    Directory of Open Access Journals (Sweden)

    Yongxiang Li

    2009-01-01

    Full Text Available The fabrication process and the growth mechanism of titanium/titania nanotubes prepared by anodization process is reviewed, and their applications in the fields of dye sensitized solar cells, photocatalysts, electrochromic devices, gas sensors, and biomaterials are presented. The anodization of Ti thin films on different substrates and the growth process of anodic titanium oxide are described using the current-time curves. Special attention is paid on the influences of the initial film smoothness on the resulted nanoporous morphologies. The “threshold barrier layer thickness model” is used to discuss the growth mechanism. As a case study for gas sensing, anodized highly ordered TiO2 nanotube arrays and nanoporous thin films that show porous surface with an average diameter of 25 nm and interpore distance of 40 nm were prepared. Gas sensors based on such nanotube arrays and nanoporous thin films were fabricated, and their sensing properties were investigated. Excellent H2 gas sensing properties were obtained for sensors prepared from these highly ordered TiO2 nanotube arrays, which present stable response even at a low operating temperature of 90°C. Based on our experimental results, “H-induced O2− desorption” mechanism was used for explaining the hydrogen gas sensing mechanism.

  19. Acceleration sensing based on piezoresistive effect of carbon nanotube films

    Institute of Scientific and Technical Information of China (English)

    WEI Feng-yan; SHEN Hui-juan; CAO Chun-lan; LIAO Ke-jun; HU Chen-guo

    2006-01-01

    Based on piezoresistive effect,the acceleration sensitivity of multi-walled canbon nanotube (MWNT) films was investigated.A three-point bending technique was presented to measure the piezoresistivity,which used a bending stress applied to the samples while making MWNT films wheeling with a rotational machine.The experimental results showed that the fractional increase in resistance increases linearly versus the increase of centripetal acceleration,and there is a linear relationship between the acceleration and the strain.These shed light on using carbon nanotube films as acceleration sensors for many potential applications.

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

    CERN Document Server

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

    2014-01-01

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

  1. Progress in Dielectrophoretic Assembly of Carbon Nanotubes for Sensing Application

    OpenAIRE

    2016-01-01

    Carbon nanotubes (CNTs) have shown their potential for broad applications in field effect transistor, field emission, interconnects, energy storage, biomedicine, and many others, due to their excellent electrical, thermal, and mechanical properties. One requirement for many of these applications is to assemble CNTs into designated devices. As a promising nanomanipulation method, dielectrophoresis (DEP) has been widely applied to assemble CNTs in the fabrication of CNT-based nanodevices. This ...

  2. Ozone Sensing Based on Palladium Decorated Carbon Nanotubes

    OpenAIRE

    2014-01-01

    Multiwall carbon nanotubes (MWCNTs) were easily and efficiently decorated with Pd nanoparticles through a vapor-phase impregnation-decomposition method starting from palladium acetylacetonates. The sensor device consisted on a film of sensitive material (MWCNTs-Pd) deposited by drop coating on platinum interdigitated electrodes on a SiO2 substrate. The sensor exhibited a resistance change to ozone (O3) with a response time of 60 s at different temperatures and the capability of detecting conc...

  3. Method of Making an Electroactive Sensing/Actuating Material for Carbon Nanotube Polymer Composite

    Science.gov (United States)

    Ounaies, Zoubeida (Inventor); Park, Cheol (Inventor); Harrison, Joycelyn S. (Inventor); Holloway, Nancy M. (Inventor); Draughon, Gregory K. (Inventor)

    2009-01-01

    An electroactive sensing or actuating material comprises a composite made from a polymer with polarizable moieties and an effective amount of carbon nanotubes incorporated in the polymer for a predetermined electromechanical operation of the composite when such composite is affected by an external stimulus. In another embodiment, the composite comprises a, third component of micro -sized to nano-sized particles of an electroactive ceramic that is also incorporated in the polymer matrix. The method for making the three-phase composite comprises either incorporating the carbon nanotubes in the polymer matrix before incorporation of the particles of ceramic or mixing the carbon nanotubes and particles of ceramic together in a solution before incorporation in the polymer matrix.

  4. Sensing/actuating materials made from carbon nanotube polymer composites and methods for making same

    Science.gov (United States)

    Ounaies, Zoubeida (Inventor); Park, Cheol (Inventor); Harrison, Joycelyn S. (Inventor); Holloway, Nancy M. (Inventor); Draughon, Gregory K. (Inventor)

    2008-01-01

    An electroactive sensing or actuating material comprises a composite made from a polymer with polarizable moieties and an effective amount of carbon nanotubes incorporated in the polymer for a predetermined electromechanical operation of the composite when such composite is affected by an external stimulus. In another embodiment, the composite comprises a third component of micro-sized to nano-sized particles of an electroactive ceramic that is also incorporated in the polymer matrix. The method for making the three-phase composite comprises either incorporating the carbon nanotubes in the polymer matrix before incorporation of the particles of ceramic or mixing the carbon nanotubes and particles of ceramic together in a solution before incorporation in the polymer matrix.

  5. Hydrogen Sensing with Ni-Doped TiO2 Nanotubes

    Directory of Open Access Journals (Sweden)

    Congqin Ning

    2013-07-01

    Full Text Available Doping with other elements is one of the efficient ways to modify the physical and chemical properties of TiO2 nanomaterials. In the present work, Ni-doped TiO2 nanotubes were fabricated through anodic oxidation of NiTi alloy and further annealing treatment. The hydrogen sensing properties of the nanotube sensor were investigated. It was found that the Ni-doped TiO2 nanotubes were sensitive to an atmosphere of 1,000 ppm hydrogen, showing a good response at both room temperature and elevated temperatures. A First-Principle simulation revealed that, in comparison with pure anatase TiO2 oxide, Ni doping in the TiO2 oxide could result in a decreased bandgap. When the oxide sensor adsorbed a certain amount of hydrogen the bandgap increased and the acceptor impurity levels was generated, which resulted in a change of the sensor resistance.

  6. Enhanced gas sensing performance of electrospun Pt-functionalized NiO nanotubes with chemical and electronic sensitization.

    Science.gov (United States)

    Fu, Jiecai; Zhao, Changhui; Zhang, Junli; Peng, Yong; Xie, Erqing

    2013-08-14

    Pt-functionalized NiO composite nanotubes were synthesized by a simple electrospinning method, and their morphology, chemistry, and crystal structure have been characterized at the nanoscale. It was found that the Pt nanoparticles were dispersed uniformly in the NiO nanotubes, and the Pt-functionalized NiO composite nanotubes showed some dendritic structure in the body of nanotubes just like thorns growing in the nanotubes. Compared with the pristine NiO nanotube based gas sensor and other NiO-based gas sensors reported previously, the Pt-functionalized NiO composite nanotube based gas sensor showed substantially enhanced electrical responses to target gas (methane, hydrogen, acetone, and ethanol), especially ethanol. The NiO-Pt 0.7% composite nanotube based gas sensor displayed a response value of 20.85 at 100 ppm at ethanol and 200 °C, whereas the pristine NiO nanotube based gas sensor only showed a response of 2.06 under the same conditions. Moreover, the Pt-functionalized NiO composite nanotube based gas sensor demonstrated outstanding gas selectivity for ethanol against methane, hydrogen, and acetone. The reason for which the Pt-functionalized NiO composite nanotube based gas sensor obviously enhanced the gas sensing performance is attributed to the role of Pt on the chemical sensitization (catalytic oxidation) of target gases and the electronic sensitization (Fermi-level shifting) of NiO.

  7. Isotope engineering of carbon nanotube systems.

    Science.gov (United States)

    Simon, F; Kramberger, Ch; Pfeiffer, R; Kuzmany, H; Zólyomi, V; Kürti, J; Singer, P M; Alloul, H

    2005-07-01

    The synthesis of a unique isotope engineered system, double-wall carbon nanotubes with natural carbon outer and highly 13C enriched inner walls, is reported from isotope enriched fullerenes encapsulated in single-wall carbon nanotubes (SWCNTs). The material allows the observation of the D line of the highly defect-free inner tubes that can be related to a curvature induced enhancement of the electron-phonon coupling. Ab initio calculations explain the inhomogeneous broadening of inner tube Raman modes due to the distribution of different isotopes. Nuclear magnetic resonance shows a significant contrast of the isotope enriched inner SWCNTs compared to other carbon phases and provides a macroscopic measure of the inner tube mass content. The high curvature of the small diameter inner tubes manifests in an increased distribution of the chemical shift tensor components.

  8. Synthesis, Characterization and Electrochemical Sensing of Tb2O3 Nanotubes

    Science.gov (United States)

    Sabari Arul, N.; Vidya, J.; Ramya, V.; Mangalaraj, D.

    2016-11-01

    One dimensional terbium oxide (Tb2O3) nanotubes have been synthesized by using surfactant free precipitation method and investigated its non-enzymatic electrochemical detection for hydrogen peroxide (H2O2). The structural analysis and x-ray diffraction data confirmed the formation of cubic phase Tb2O3 in the synthesized Tb2O3 nanotubes. The optical property of the synthesized product was investigated by ultraviolet spectroscopy and photoluminescence (PL) studies. The PL spectrum of Tb2O3 nanotubes exhibited a strong green luminescence corresponding to 5D4 → 7F5 transition of Tb3+ ions. The non-enzymatic hydrogen peroxide (H2O2) sensing of Tb2O3 nanotubes/carbon paper modified electrodes in 1 M KCl electrolyte was carried out using cyclic voltammetry and amperometric (i-t) analysis. The enhanced electrocatalytic behavior was observed for Tb2O3 nanotubes with an excellent sensitivity of 875 μA mM-1 cm-2, linear ranges of 0.5-5 mM and a low detection limit of 5 μM.

  9. Synthesis, Characterization and Electrochemical Sensing of Tb2O3 Nanotubes

    Science.gov (United States)

    Sabari Arul, N.; Vidya, J.; Ramya, V.; Mangalaraj, D.

    2017-02-01

    One dimensional terbium oxide (Tb2O3) nanotubes have been synthesized by using surfactant free precipitation method and investigated its non-enzymatic electrochemical detection for hydrogen peroxide (H2O2). The structural analysis and x-ray diffraction data confirmed the formation of cubic phase Tb2O3 in the synthesized Tb2O3 nanotubes. The optical property of the synthesized product was investigated by ultraviolet spectroscopy and photoluminescence (PL) studies. The PL spectrum of Tb2O3 nanotubes exhibited a strong green luminescence corresponding to 5D4 → 7F5 transition of Tb3+ ions. The non-enzymatic hydrogen peroxide (H2O2) sensing of Tb2O3 nanotubes/carbon paper modified electrodes in 1 M KCl electrolyte was carried out using cyclic voltammetry and amperometric ( i- t) analysis. The enhanced electrocatalytic behavior was observed for Tb2O3 nanotubes with an excellent sensitivity of 875 μA mM-1 cm-2, linear ranges of 0.5-5 mM and a low detection limit of 5 μM.

  10. Ozone sensing based on palladium decorated carbon nanotubes.

    Science.gov (United States)

    Colindres, Selene Capula; Aguir, Khalifa; Cervantes Sodi, Felipe; Vargas, Luis Villa; Salazar, José Moncayo; Febles, Vicente Garibay

    2014-04-14

    Multiwall carbon nanotubes (MWCNTs) were easily and efficiently decorated with Pd nanoparticles through a vapor-phase impregnation-decomposition method starting from palladium acetylacetonates. The sensor device consisted on a film of sensitive material (MWCNTs-Pd) deposited by drop coating on platinum interdigitated electrodes on a SiO₂ substrate. The sensor exhibited a resistance change to ozone (O₃) with a response time of 60 s at different temperatures and the capability of detecting concentrations up to 20 ppb. The sensor shows the best response when exposed to O3 at 120 °C. The device shows a very reproducible sensor performance, with high repeatability, full recovery and efficient response.

  11. Carbon Nanotube Field-Effect Transistor for DNA Sensing

    Science.gov (United States)

    Xuan, Chu T.; Thuy, Nguyen T.; Luyen, Tran T.; Huyen, Tran T. T.; Tuan, Mai A.

    2017-01-01

    A field-effect transistor (FET) using carbon nanotubes (CNTs) as the conducting channel (CNTFET) has been developed, designed such that the CNT conducting channel (15 μm long, 700 μm wide) is directly exposed to medium containing target deoxyribonucleic acid (DNA). The CNTFET operates at high ON-current of 1.91 μA, ON/OFF-current ratio of 1.2 × 105, conductance of 4.3 μS, and leakage current of 16.4 pA. We present initial trials showing the response of the CNTFET to injection of target DNA into aqueous medium.

  12. CARBON NANOTUBES: AN APPROACH TO NOVEL DRUG DELIVERY SYSTEM

    Directory of Open Access Journals (Sweden)

    M. H. Alai et al.

    2012-01-01

    Full Text Available Carbon nanotubes are cylindrical carbon molecules have novel properties, making them potentially useful in many applications in nanotechnology, electronics, optics, and other fields of material science as well as potential uses in architectural fields. They have unique electronic, mechanical, optical and chemical properties that make them good candidates for a wide variety of applications, including drug transporters, new therapeutics, delivery systems and diagnostics. Their unique surface area, stiffness, strength and resilience have led to much excitement in the field of pharmacy. Nanotubes are categorized as single-walled nanotubes, multiple walled nanotubes. Various techniques have been developed to produce nanotubes in sizeable quantities, including arc discharge, laser ablation, chemical vapor deposition. They can pass through membranes, carrying therapeutic drugs, vaccines and nucleic acids deep into the cell to targets previously unreachable. Purification of the tubes can be divided into a couple of main techniques: oxidation, acid treatment, annealing, sonication, filtering and functionalization techniques. The main problem of insolubility in aqueous media has been solved by developing a synthetic protocol that allows highly water-soluble carbon NTs to be obtained. The modifications are done to improve efficiency of carbon nanotubes by formulating luminescent carbon nanotubes, ultrathin carbon nanoneedles, magnetically guided nanotubes. The application of carbon nanotube in tissue engineering, drug carrier release system, wound healing, in cancer treatment and as biosensor. Researchers have recently developed a new approach to Boron Neutron Capture Therapy in the treatment of cancer using substituted Carborane-Appended Water-Soluble single-wall carbon nanotubes.

  13. Modeling of rf energy sensing and harvesting using the giant thermoelectric effect in carbon nanotubes

    Science.gov (United States)

    Dragoman, M.; Dragoman, D.; Plana, R.

    2007-10-01

    The paper presents the modeling of rf energy sensing and harvesting using the giant thermoelectric effect encountered in carbon nanotubes and proposes a harvester based on this principle. The rf energy is transformed into dc voltage, conferring to the harvesting device the property of self-powering and thus the portability, which is a prerequisite of ultradense wireless nodes that form advanced wireless sensor networks and, in principle, of any portable wireless device.

  14. Dynamic Response of Tapered Optical Multimode Fiber Coated with Carbon Nanotubes for Ethanol Sensing Application

    OpenAIRE

    2015-01-01

    Ethanol is a highly combustible chemical universally designed for biomedical applications. In this paper, optical sensing performance of tapered multimode fiber tip coated with carbon nanotube (CNT) thin film towards aqueous ethanol with different concentrations is investigated. The tapered optical multimode fiber tip is coated with CNT using drop-casting technique and is annealed at 70 °C to enhance the binding of the nanomaterial to the silica fiber tip. The optical fiber tip and the CNT se...

  15. Ozone Sensing Based on Palladium Decorated Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Selene Capula Colindres

    2014-04-01

    Full Text Available Multiwall carbon nanotubes (MWCNTs were easily and efficiently decorated with Pd nanoparticles through a vapor-phase impregnation-decomposition method starting from palladium acetylacetonates. The sensor device consisted on a film of sensitive material (MWCNTs-Pd deposited by drop coating on platinum interdigitated electrodes on a SiO2 substrate. The sensor exhibited a resistance change to ozone (O3 with a response time of 60 s at different temperatures and the capability of detecting concentrations up to 20 ppb. The sensor shows the best response when exposed to O3 at 120 °C. The device shows a very reproducible sensor performance, with high repeatability, full recovery and efficient response.

  16. Vertically aligned carbon nanotubes for sensing unidirectional fluid flow

    Energy Technology Data Exchange (ETDEWEB)

    Kiani, Keivan, E-mail: k_kiani@kntu.ac.ir

    2015-05-15

    From applied mechanics points of view, potential application of ensembles of single-walled carbon nanotubes (SWCNTs) as fluid flow sensors is aimed to be examined. To this end, useful nonlocal analytical and numerical models are developed. The deflection of the ensemble of SWCNTs at the tip is introduced as a measure of its sensitivity. The influences of the length and radius of the SWCNT, intertube distance, fluid flow velocity, and distance of the ensemble from the leading edge of the rigid base on the deflection field of the ensemble are comprehensively examined. The obtained results display how calibration of an ensemble of SWCNTs can be methodically carried out in accordance with the characteristics of the ensemble and the external fluid flow.

  17. Ozone Sensing Based on Palladium Decorated Carbon Nanotubes

    Science.gov (United States)

    Colindres, Selene Capula; Aguir, Khalifa; Sodi, Felipe Cervantes; Vargas, Luis Villa; Moncayo Salazar, José A.; Febles, Vicente Garibay

    2014-01-01

    Multiwall carbon nanotubes (MWCNTs) were easily and efficiently decorated with Pd nanoparticles through a vapor-phase impregnation-decomposition method starting from palladium acetylacetonates. The sensor device consisted on a film of sensitive material (MWCNTs-Pd) deposited by drop coating on platinum interdigitated electrodes on a SiO2 substrate. The sensor exhibited a resistance change to ozone (O3) with a response time of 60 s at different temperatures and the capability of detecting concentrations up to 20 ppb. The sensor shows the best response when exposed to O3 at 120 °C. The device shows a very reproducible sensor performance, with high repeatability, full recovery and efficient response. PMID:24736133

  18. Catalytic systems of cumene oxidation based on multiwalled carbon nanotubes

    Science.gov (United States)

    Kobotaeva, N. S.; Skorokhodova, T. S.; Ryabova, N. V.

    2015-03-01

    Catalytic systems for cumene oxidation were prepared on the basis of silver-activated carbon nanotubes. Silver lies on the surface of the carbon nanotubes in the nanocrystalline state and has a size of 15-20 nm. The use of the obtained catalytic systems in cumene oxidation with molecular oxygen allowed a considerable decrease in the oxidation temperature and an increase in selectivity.

  19. Compressed sensing for distributed systems

    CERN Document Server

    Coluccia, Giulio; Magli, Enrico

    2015-01-01

    This book presents a survey of the state-of-the art in the exciting and timely topic of compressed sensing for distributed systems. It has to be noted that, while compressed sensing has been studied for some time now, its distributed applications are relatively new. Remarkably, such applications are ideally suited to exploit all the benefits that compressed sensing can provide. The objective of this book is to provide the reader with a comprehensive survey of this topic, from the basic concepts to different classes of centralized and distributed reconstruction algorithms, as well as a comparison of these techniques. This book collects different contributions on these aspects. It presents the underlying theory in a complete and unified way for the first time, presenting various signal models and their use cases. It contains a theoretical part collecting latest results in rate-distortion analysis of distributed compressed sensing, as well as practical implementations of algorithms obtaining performance close to...

  20. Dispersion monitoring of carbon nanotube modified epoxy systems

    Science.gov (United States)

    Gkikas, G.; Saganas, Ch.; Grammatikos, S. A.; Maistros, Gh. M.; Barkoula, N.-M.; Paipetis, A. S.

    2012-04-01

    The remarkable mechanical and electrical properties exhibited by carbon nanotubes (CNTs) have encouraged efforts to develop mass production techniques. As a result, CNTs are becoming increasingly available, and more attention from both the academic world and industry has focused on the applications of CNTs in bulk quantities. These opportunities include the use of CNTs as conductive filler in insulating polymer matrices and as reinforcement in structural materials. The use of composites made from an insulating matrix and highly conductive fillers is becoming more and more important due to their ability to electromagnetically shield and prevent electrostatic charging of electronic devices. In recent years, different models have been proposed to explain the formation of the conductive filler network. Moreover, intrinsic difficulties and unresolved issues related to the incorporation of carbon nanotubes as conductive fillers in an epoxy matrix and the interpretation of the processing behavior have not yet been resolved. In this sense, a further challenge is becoming more and more important in composite processing: cure monitoring and optimization. This paper considers the potential for real-time control of cure cycle and dispersion of a modified epoxy resin system commonly utilized in aerospace composite parts. It shows how cure cycle and dispersion control may become possible through realtime in-situ acquisition of dielectric signal from the curing resin, analysis of its main components and identification of the significant features.

  1. ZnO Functionalization of Surface Pre-treated Multi-walled Carbon Nanotubes for Methane Sensing

    Science.gov (United States)

    Bare carbon nanotubes (CNTs) cannot be used to sense most gases due to poor bonding between the chemically inert graphitic surface and the different compounds CNTs are exposed to. Consequently, for gas sensing applications, functionalization of CNTs with reactive compounds is req...

  2. Single-WalledCarbon Nanotube Networked Field-Effect Transistors Functionalized with Thiolated Heme for NO2 Sensing

    Institute of Scientific and Technical Information of China (English)

    魏昂; 李维维; 汪静霞; 龙庆; 王钊; 熊莉; 董晓臣; 黄维

    2011-01-01

    The gas sensing properties of the single-walled carbon nanotube networked field-effect transistors for NO2 are investigated. After the modification of the gold contact electrodes of the carbon nanotube transistors with the thiolated heme, the NO2 sensing results indicate that the sensing sensitivity of the modified transistors is enhanced greatly and the sensing limit can reach below Woppb. It is also proposed that the mechanism of the sensitivity enhancement for NO2 detection mainly results from the modulation of the Schottky energy barrier at the Au/CNTs junction upon thiolated heme facilitated NO2 adsorption.%The gas sensing properties of the single-walled carbon nanotube networked field-effect transistors for NO2 are investigated.After the modification of the gold contact electrodes of the carbon nanotube transistors with the thiolated heme,the NO2 sensing results indicate that the sensing sensitivity of the modified transistors is enhanced greatly and the sensing limit can reach below 100ppb.It is also proposed that the mechanism of the sensitivity enhancement for NO2 detection mainly results from the modulation of the Schottky energy barrier at the Au/CNTs junction upon thiolated heme facilitated NO2 adsorption.

  3. Analytical Calculation of Sensing Parameters on Carbon Nanotube Based Gas Sensors

    Directory of Open Access Journals (Sweden)

    Elnaz Akbari

    2014-03-01

    Full Text Available Carbon Nanotubes (CNTs are generally nano-scale tubes comprising a network of carbon atoms in a cylindrical setting that compared with silicon counterparts present outstanding characteristics such as high mechanical strength, high sensing capability and large surface-to-volume ratio. These characteristics, in addition to the fact that CNTs experience changes in their electrical conductance when exposed to different gases, make them appropriate candidates for use in sensing/measuring applications such as gas detection devices. In this research, a model for a Field Effect Transistor (FET-based structure has been developed as a platform for a gas detection sensor in which the CNT conductance change resulting from the chemical reaction between NH3 and CNT has been employed to model the sensing mechanism with proposed sensing parameters. The research implements the same FET-based structure as in the work of Peng et al. on nanotube-based NH3 gas detection. With respect to this conductance change, the I–V characteristic of the CNT is investigated. Finally, a comparative study shows satisfactory agreement between the proposed model and the experimental data from the mentioned research.

  4. Toward Distinct Element Method Simulations of Carbon Nanotube Systems

    Science.gov (United States)

    Akatyeva, Evgeniya; Anderson, Tyler; Nikiforov, Ilia; Potyondy, David; Ballarini, Roberto; Dumitrica, Traian

    2011-03-01

    We propose distinct element method modeling of carbon nanotube systems. The atomic-level description of an individual nanotube is coarse-grained into a chain of spherical elements that interact by parallel bonds located at their contacts. The spherical elements can lump multiple translational unit cells of the carbon nanotube and have both translational and rotational degrees of freedom. The discrete long ranged interaction between nanotubes is included in a van der Waals contact of nonmechanical nature that acts simultaneously with the parallel bonds. The created mesoscopic model is put into service by simulating a realistic carbon nanotube ring. The ring morphology arises from the energy balance stored in both parallel and van der Waals bonds. We thank NSF CAREER under Grant No. CMMI-0747684, NSF under Grant No. CMMI 0800896.

  5. Multi-Walled Carbon Nanotube-Doped Tungsten Oxide Thin Films for Hydrogen Gas Sensing

    OpenAIRE

    2010-01-01

    In this work we have fabricated hydrogen gas sensors based on undoped and 1 wt% multi-walled carbon nanotube (MWCNT)-doped tungsten oxide (WO3) thin films by means of the powder mixing and electron beam (E-beam) evaporation technique. Hydrogen sensing properties of the thin films have been investigated at different operating temperatures and gas concentrations ranging from 100 ppm to 50,000 ppm. The results indicate that the MWCNT-doped WO3 thin film exhibits high sensitivity and selectivity ...

  6. CO2 sensing at room temperature using carbon nanotubes coated core fiber Bragg grating

    Science.gov (United States)

    Shivananju, B. N.; Yamdagni, S.; Fazuldeen, R.; Sarin Kumar, A. K.; Hegde, G. M.; Varma, M. M.; Asokan, S.

    2013-06-01

    The sensing of carbon dioxide (CO2) at room temperature, which has potential applications in environmental monitoring, healthcare, mining, biotechnology, food industry, etc., is a challenge for the scientific community due to the relative inertness of CO2. Here, we propose a novel gas sensor based on clad-etched Fiber Bragg Grating (FBG) with polyallylamine-amino-carbon nanotube coated on the surface of the core for detecting the concentrations of CO2 gas at room temperature, in ppm levels over a wide range (1000 ppm-4000 ppm). The limit of detection observed in polyallylamine-amino-carbon nanotube coated core-FBG has been found to be about 75 ppm. In this approach, when CO2 gas molecules interact with the polyallylamine-amino-carbon nanotube coated FBG, the effective refractive index of the fiber core changes, resulting in a shift in Bragg wavelength. The experimental data show a linear response of Bragg wavelength shift for increase in concentration of CO2 gas. Besides being reproducible and repeatable, the technique is fast, compact, and highly sensitive.

  7. CO2 sensing at room temperature using carbon nanotubes coated core fiber Bragg grating.

    Science.gov (United States)

    Shivananju, B N; Yamdagni, S; Fazuldeen, R; Sarin Kumar, A K; Hegde, G M; Varma, M M; Asokan, S

    2013-06-01

    The sensing of carbon dioxide (CO2) at room temperature, which has potential applications in environmental monitoring, healthcare, mining, biotechnology, food industry, etc., is a challenge for the scientific community due to the relative inertness of CO2. Here, we propose a novel gas sensor based on clad-etched Fiber Bragg Grating (FBG) with polyallylamine-amino-carbon nanotube coated on the surface of the core for detecting the concentrations of CO2 gas at room temperature, in ppm levels over a wide range (1000 ppm-4000 ppm). The limit of detection observed in polyallylamine-amino-carbon nanotube coated core-FBG has been found to be about 75 ppm. In this approach, when CO2 gas molecules interact with the polyallylamine-amino-carbon nanotube coated FBG, the effective refractive index of the fiber core changes, resulting in a shift in Bragg wavelength. The experimental data show a linear response of Bragg wavelength shift for increase in concentration of CO2 gas. Besides being reproducible and repeatable, the technique is fast, compact, and highly sensitive.

  8. Room temperature alcohol sensing by oxygen vacancy controlled TiO{sub 2} nanotube array

    Energy Technology Data Exchange (ETDEWEB)

    Hazra, A.; Dutta, K.; Bhowmik, B.; Bhattacharyya, P., E-mail: pb-etc-besu@yahoo.com [Nano-Thin Films and Solid State Gas Sensor Devices Laboratory, Department of Electronics and Telecommunication Engineering, Indian Institute of Engineering Science and Technology (IIEST), Shibpur, Howrah (India); Chattopadhyay, P. P. [Department of Metallurgy and Materials Engineering, Indian Institute of Engineering Science and Technology (IIEST), Shibpur, Howrah (India)

    2014-08-25

    Oxygen vacancy (OV) controlled TiO{sub 2} nanotubes, having diameters of 50–70 nm and lengths of 200–250 nm, were synthesized by electrochemical anodization in the mixed electrolyte comprising NH{sub 4}F and ethylene glycol with selective H{sub 2}O content. The structural evolution of TiO{sub 2} nanoforms has been studied by field emission scanning electron microscopy. Variation in the formation of OVs with the variation of the structure of TiO{sub 2} nanoforms has been evaluated by photoluminescence and X-ray photoelectron spectroscopy. The sensor characteristics were correlated to the variation of the amount of induced OVs in the nanotubes. The efficient room temperature sensing achieved by the control of OVs of TiO{sub 2} nanotube array has paved the way for developing fast responding alcohol sensor with corresponding response magnitude of 60.2%, 45.3%, and 36.5% towards methanol, ethanol, and 2-propanol, respectively.

  9. ZnO nanotube array: Gas sensing properties at room temperature

    Science.gov (United States)

    Dadhich, B.; Ganapathi, S. Kailasa; Priyam, A.; Kaur, Manmeet; Debnath, A. K.; Muthe, K. P.; Gadkari, S. C.

    2017-05-01

    In the present study, ZnO nanotube arrays were synthesized from hydrothermally grown ZnO nanowires by selective chemical etching, using KCl as dissolving solution. Synthesized ZnO nanotube arrays were characterized using X-ray diffraction, scanning electron microscopy, UV-visible and Raman spectroscopy. Room temperature gas sensing properties of these arrays were investigated towards various toxic gases and the results were compared to that of ZnO nanowire arrays. Samples of ZnO nano tube arrays showed better sensor response to both H2S (4.2 for 5 ppm) and NO2 (13 for 1.5 ppm) as compared to samples of ZnO nanowires array which exhibited a sensor response of 3.7 towards 5 ppm H2S and 1 towards 1.5 ppm NO2. The enhancement of sensor response in nanotube arrays can be attributed to the hollow morphology of the ZnO NT which offers higher surface area. Oxygen adsorption in this case takes place on both inner and outer surfaces of the tube resulting in larger change in resistance.

  10. Compressive Sensing in Communication Systems

    DEFF Research Database (Denmark)

    Fyhn, Karsten

    2013-01-01

    Wireless communication is omnipresent today, but this development has led to frequency spectrum becoming a limited resource. Furthermore, wireless devices become more and more energy-limited, due to the demand for continual wireless communication of higher and higher amounts of information....... The need for cheaper, smarter and more energy efficient wireless devices is greater now than ever. This thesis addresses this problem and concerns the application of the recently developed sampling theory of compressive sensing in communication systems. Compressive sensing is the merging of signal...... acquisition and compression. It allows for sampling a signal with a rate below the bound dictated by the celebrated Shannon-Nyquist sampling theorem. In some communication systems this necessary minimum sample rate, dictated by the Shannon-Nyquist sampling theorem, is so high it is at the limit of what...

  11. Dynamic response of tapered optical multimode fiber coated with carbon nanotubes for ethanol sensing application.

    Science.gov (United States)

    Shabaneh, Arafat; Girei, Saad; Arasu, Punitha; Mahdi, Mohd; Rashid, Suraya; Paiman, Suriati; Yaacob, Mohd

    2015-05-04

    Ethanol is a highly combustible chemical universally designed for biomedical applications. In this paper, optical sensing performance of tapered multimode fiber tip coated with carbon nanotube (CNT) thin film towards aqueous ethanol with different concentrations is investigated. The tapered optical multimode fiber tip is coated with CNT using drop-casting technique and is annealed at 70 °C to enhance the binding of the nanomaterial to the silica fiber tip. The optical fiber tip and the CNT sensing layer are micro-characterized using FESEM and Raman spectroscopy techniques. When the developed sensor was exposed to different concentrations of ethanol (5% to 80%), the sensor reflectance reduced proportionally. The developed sensors showed high sensitivity, repeatability and fast responses (<55 s) towards ethanol.

  12. Dynamic Response of Tapered Optical Multimode Fiber Coated with Carbon Nanotubes for Ethanol Sensing Application

    Directory of Open Access Journals (Sweden)

    Arafat Shabaneh

    2015-05-01

    Full Text Available Ethanol is a highly combustible chemical universally designed for biomedical applications. In this paper, optical sensing performance of tapered multimode fiber tip coated with carbon nanotube (CNT thin film towards aqueous ethanol with different concentrations is investigated. The tapered optical multimode fiber tip is coated with CNT using drop-casting technique and is annealed at 70 °C to enhance the binding of the nanomaterial to the silica fiber tip. The optical fiber tip and the CNT sensing layer are micro-characterized using FESEM and Raman spectroscopy techniques. When the developed sensor was exposed to different concentrations of ethanol (5% to 80%, the sensor reflectance reduced proportionally. The developed sensors showed high sensitivity, repeatability and fast responses (<55 s towards ethanol.

  13. Passive wireless strain and pH sensing using carbon nanotube-gold nanocomposite thin films

    Science.gov (United States)

    Loh, Kenneth J.; Lynch, Jerome P.; Kotov, Nicholas A.

    2007-04-01

    The recent development of wireless sensors for structural health monitoring has revealed their strong dependency on portable, limited battery supplies. Unlike current wireless sensors, passive radio frequency identification (RFID) systems based on inductive coupling can wirelessly receive power from a portable reader while transmitting collected data back. In this paper, preliminary results of a novel inductively coupled strain and corrosion sensor based upon material fabrication techniques from the nanotechnology field are presented. By varying polyelectrolyte species during a layer-by-layer fabrication process, carbon nanotube-polyelectrolyte multilayer thin film sensors sensitive to different mechanical (e.g. strain) and chemical (e.g. pH) stimuli can be produced. Validation studies conducted with different carbon nanotube thin films designed as either strain or pH sensors reveal high sensitivity and linear performance. When coupled with a copper inductive coil antenna, resulting RFID-based sensors exhibit wirelessly readable changes in resonant frequency and bandwidth. Furthermore, a carbon nanotube-gold nanocomposite thin film is fabricated and patterned into a highly conductive coil structure to realize a novel thin film inductive antenna. Preliminary results indicate that nanotube-gold nanocomposites exhibit resonance conditions, holding great promise for future RFID applications.

  14. Supramolecular self-assembly of biopolymers with carbon nanotubes for biomimetic and bio-inspired sensing and actuation.

    Science.gov (United States)

    Lu, Luhua; Chen, Wei

    2011-06-01

    Biopolymers are important natural multifunctional macromolecules for biomimetic and bio-inspired advanced functional material design. They are not only simple dispersants for carbon nanotube stabilization as they have been found to have specific interactions with carbon nanotubes. Their molecular activity, orientation and crystallization are influenced by the CNTs, which endow their composites with a variety of novel sensing and actuation performances. This review focuses on the progress in supramolecular self-assembly of biopolymers with carbon nanotubes, and their advances in sensing and actuation. To promote the development of advanced biopolymer/CNT functional materials, new electromechanical characteristics of biopolymer/CNT composites are discussed in detail based on the relationship between the microscopic biopolymer structures and the macroscopic composite properties.

  15. Precise semiconductor nanotubes and nanocorrugated quantum systems

    Science.gov (United States)

    Prinz, V. Ya.

    2004-08-01

    A concept in precise nanostructuring permitting the formation of solid-state nanoshells of various shapes from monocrystalline InGaAs/GaAs or Si/GeSi strained heterofilms, or from metal-semiconductor, metal-metal and hybrid films is outlined. Ultra-thin strained films released from the massive substrate tend to acquire a new equilibrium shape for which their elastic energy is minimal. Bending off from the substrate or rolling into cylindrical objects, the films form nanotubes, rings, helices, open and closed 3D nanoshells and their ordered arrays. The present work focuses on the set of newly proposed methods and realized processes constituting a fabrication technology for these free-standing precise nanoobjects and systems. New results on the formation of spatially periodic structures, nanocorrugated systems, shells with the minimum radius of curvature of ∼1 nm, and assembling these shells in even more complex architectures, for example, quantum-dots molecules, are described. The fabricated nanoshells offer much promise as building blocks for nanoelectronic and nanomechanic devices, their fabrication technology being quite compatible with the well-established integrated-circuit technology.

  16. Electrochemical impedance spectroscopy versus cyclic voltammetry for the electroanalytical sensing of capsaicin utilising screen printed carbon nanotube electrodes.

    Science.gov (United States)

    Randviir, Edward P; Metters, Jonathan P; Stainton, John; Banks, Craig E

    2013-05-21

    Screen printed carbon nanotube electrodes (SPEs) are explored as electroanalytical sensing platforms for the detection of capsaicin in both synthetic capsaicin solutions and capsaicin extracted from chillies and chilli sauces utilising both cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It is found that the technique which is most applicable to the electroanalytical detection of capsaicin depends upon the analyte concentration: for the case of low capsaicin concentrations, CV is a more appropriate method as capsaicin exhibits characteristic voltammetric waves of peak heights relevant to the capsaicin concentration; but for the case of high capsaicin concentrations where the voltammetric waves merge and migrate out of the potential window, EIS is shown to be a more appropriate technique, owing to the observed linear increases in R(ct) with increasing concentration. Furthermore, we explore different types of screen printed carbon nanotube electrodes, namely single- and multi- walled carbon nanotubes, finding that they are technique-specific: for the case of low capsaicin concentrations, single-walled carbon nanotube SPEs are preferable (SW-SPE); yet for the case of EIS at high capsaicin concentrations, multi-walled carbon nanotube SPEs (MW-SPE) are preferred, based upon analytical responses. The analytical performance of CV and EIS is applied to the sensing of capsaicin in grown chillies and chilli sauces and is critically compared to 'gold standard' HPLC analysis.

  17. Platinum Electrodeposition on Unsupported Single Wall Carbon Nanotubes and Its Application as Methane Sensing Material

    Science.gov (United States)

    Jesus, Enid Contes-de; Santiago, Diana; Casillas, Gilberto; Mayoral, Alvaro; Magen, Cesar; José-Yacaman, Miguel; Li, Jing; Cabrera, Carlos R.

    2013-01-01

    This paper reports the decoration of single wall carbon nanotubes (SWCNTs) with platinum (Pt) nanoparticles using an electrochemical technique, rotating disk slurry electrode (RoDSE). Pt/SWCNTs were electrochemically characterized by cyclic voltammetry technique (CV) and physically characterized through the use of transmission electron microscopy (TEM), energy dispersive spectroscopy - X-ray florescence (EDS-XRF) and X-ray diffraction (XRD). After characterization it was found that electrodeposited nanoparticles had an average particle size of 4.1 ± 0.8 nm. Pt/SWCNTs were used as sensing material for methane (CH4) detection and showed improved sensing properties in a range of concentration from 50 ppm to 200 ppm parts per million (ppm) at room temperature, when compared to other Pt/CNTs-based sensors. The use of this technique for the preparation of Pt/SWCNTs opens a new possibility in the bulk preparation of samples using an electrochemical method and thus their potential use in a wide variety of applications in chemical sensing, fuel cell and others. PMID:24991061

  18. Multi-Walled Carbon Nanotube-Doped Tungsten Oxide Thin Films for Hydrogen Gas Sensing

    Directory of Open Access Journals (Sweden)

    Adisorn Tuantranont

    2010-08-01

    Full Text Available In this work we have fabricated hydrogen gas sensors based on undoped and 1 wt% multi-walled carbon nanotube (MWCNT-doped tungsten oxide (WO3 thin films by means of the powder mixing and electron beam (E-beam evaporation technique. Hydrogen sensing properties of the thin films have been investigated at different operating temperatures and gas concentrations ranging from 100 ppm to 50,000 ppm. The results indicate that the MWCNT-doped WO3 thin film exhibits high sensitivity and selectivity to hydrogen. Thus, MWCNT doping based on E-beam co-evaporation was shown to be an effective means of preparing hydrogen gas sensors with enhanced sensing and reduced operating temperatures. Creation of nanochannels and formation of p-n heterojunctions were proposed as the sensing mechanism underlying the enhanced hydrogen sensitivity of this hybridized gas sensor. To our best knowledge, this is the first report on a MWCNT-doped WO3 hydrogen sensor prepared by the E-beam method.

  19. Multi-walled carbon nanotube-doped tungsten oxide thin films for hydrogen gas sensing.

    Science.gov (United States)

    Wongchoosuk, Chatchawal; Wisitsoraat, Anurat; Phokharatkul, Ditsayut; Tuantranont, Adisorn; Kerdcharoen, Teerakiat

    2010-01-01

    In this work we have fabricated hydrogen gas sensors based on undoped and 1 wt% multi-walled carbon nanotube (MWCNT)-doped tungsten oxide (WO(3)) thin films by means of the powder mixing and electron beam (E-beam) evaporation technique. Hydrogen sensing properties of the thin films have been investigated at different operating temperatures and gas concentrations ranging from 100 ppm to 50,000 ppm. The results indicate that the MWCNT-doped WO(3) thin film exhibits high sensitivity and selectivity to hydrogen. Thus, MWCNT doping based on E-beam co-evaporation was shown to be an effective means of preparing hydrogen gas sensors with enhanced sensing and reduced operating temperatures. Creation of nanochannels and formation of p-n heterojunctions were proposed as the sensing mechanism underlying the enhanced hydrogen sensitivity of this hybridized gas sensor. To our best knowledge, this is the first report on a MWCNT-doped WO(3) hydrogen sensor prepared by the E-beam method.

  20. Stoichiometry, Length, and Wall Thickness Optimization of TiO2 Nanotube Array for Efficient Alcohol Sensing.

    Science.gov (United States)

    Hazra, A; Bhowmik, B; Dutta, K; Chattopadhyay, P P; Bhattacharyya, P

    2015-05-13

    The present study concerns development of an efficient alcohol sensor by controlling the stoichiometry, length, and wall thickness of electrochemically grown TiO2 nanotube array for its use as the sensing layer. Judicious variation of H2O content (0, 2, 10 and 100% by volume) in the mixed electrolyte comprising ethylene glycol and NH4F resulted into the desired variation of stoichiometry. The sensor study was performed within the temperature range of 27 to 250 °C for detecting the alcohols in the concentration range of 10-1000 ppm. The nanotubes grown with the electrolyte containing 2 vol % H2O offered the maximum response magnitude. For this stoichiometry, variation of corresponding length (1.25-2.4 μm) and wall thickness (19.8-9 nm) of the nanotubes was achieved by varying the anodization time (4-16 h) and temperatures (42-87 °C), respectively. While the variation of length influenced the sensing parameters insignificantly, the best response magnitude was achieved for ∼13 nm wall thickness. The underlying sensing mechanism was correlated with the experimental findings on the basis of structural parameters of the nanotubes.

  1. Capacitive humidity sensing properties of carbon nanotubes grown on silicon nanoporous pillar array

    Institute of Scientific and Technical Information of China (English)

    JIANG WeiFen; XIAO ShunHua; ZHANG HuanYun; DONG YongFen; LI XinJian

    2007-01-01

    Multi-walled carbon nanotubes (CNTs) were grown on silicon nanoporous pillar array (Si-NPA) by thermal chemical vapor deposition method, and the structural and capacitive humidity sensing properties of CNT/Si-NPA were studied. It was found that with the relative humidity (RH) changing from 11% to 95%, a device response of ~480% was achieved at the frequency of 50000 Hz, and a linear device response curve could be obtained by adopting longitudinal logarithmic coordinate. The response/recovery times were measured to be ~20 s and ~10 s, respectively, which indicated a rather fast response/recovery rate. The adsorption-desorption dynamic cycle experiments demonstrated the high measurement reproducibility of CNT/Si-NPA sensors. These excellent performances were attributed to the unique surface structure, morphology and chemical inertness of CNT/Si-NPA.

  2. Capacitive humidity sensing properties of carbon nanotubes grown on silicon nanoporous pillar array

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Multi-walled carbon nanotubes (CNTs) were grown on silicon nanoporous pillar array (Si-NPA) by thermal chemical vapor deposition method, and the structural and capacitive humidity sensing properties of CNT/Si-NPA were studied. It was found that with the relative humidity (RH) changing from 11% to 95%, a device re-sponse of ~480% was achieved at the frequency of 50000 Hz, and a linear device response curve could be obtained by adopting longitudinal logarithmic coordinate. The response/recovery times were measured to be ~20 s and ~10 s, respectively, which indicated a rather fast response/recovery rate. The adsorption-desorption dynamic cycle experiments demonstrated the high measurement reproducibility of CNT/Si-NPA sensors. These excellent performances were attributed to the unique surface structure, morphology and chemical inertness of CNT/Si-NPA.

  3. Selective and uniform growth of single-wall carbon nanotubes (SWCNTs) for gas sensing application

    Science.gov (United States)

    Alvi, M. A.; Al-Ghamdi, A. A.; Khan, Shamshad A.

    2017-03-01

    In the present work, we have synthesized uniformly distributed single-wall carbon nanotube (SWCNT) networks with a selective diameter suitable for gas sensing device. The SWCNT networks have been synthesized on 2-nm-thick iron (Fe) catalyst-coated silicon (Si) substrates by Plasma-Enhanced Chemical Vapor Deposition (PECVD). The as-grown SWCNTs were characterized by field emission scanning electron microscopy, high-resolution transmission electron microscopy, and Raman spectroscopy techniques. Using SWCNT network, the sensitivity of ammonia (NH3) gases/vapors was recognized by their surface adsorption and desorption responses. The response curve was observed from the SWCNT network, which is due to a change in the resistance upon exposure to NH3 gas.

  4. Smart sensing surveillance video system

    Science.gov (United States)

    Hsu, Charles; Szu, Harold

    2016-05-01

    An intelligent video surveillance system is able to detect and identify abnormal and alarming situations by analyzing object movement. The Smart Sensing Surveillance Video (S3V) System is proposed to minimize video processing and transmission, thus allowing a fixed number of cameras to be connected on the system, and making it suitable for its applications in remote battlefield, tactical, and civilian applications including border surveillance, special force operations, airfield protection, perimeter and building protection, and etc. The S3V System would be more effective if equipped with visual understanding capabilities to detect, analyze, and recognize objects, track motions, and predict intentions. In addition, alarm detection is performed on the basis of parameters of the moving objects and their trajectories, and is performed using semantic reasoning and ontologies. The S3V System capabilities and technologies have great potential for both military and civilian applications, enabling highly effective security support tools for improving surveillance activities in densely crowded environments. It would be directly applicable to solutions for emergency response personnel, law enforcement, and other homeland security missions, as well as in applications requiring the interoperation of sensor networks with handheld or body-worn interface devices.

  5. Doped carbon nanotubes as a model system of biased graphene

    Science.gov (United States)

    Szirmai, P.; Márkus, B. G.; Dóra, B.; Fábián, G.; Koltai, J.; Zólyomi, V.; Kürti, J.; Náfrádi, B.; Forró, L.; Pichler, T.; Simon, F.

    2017-08-01

    Albeit difficult to access experimentally, the density of states (DOS) is a key parameter in solid-state systems, which governs several important phenomena including transport, magnetism, thermal, and thermoelectric properties. We study DOS in an ensemble of potassium intercalated single-wall carbon nanotubes and show, using electron spin resonance spectroscopy, that a sizable number of electron states are present, which gives rise to a Fermi-liquid behavior in this material. A comparison between theoretical and the experimental DOS indicates that it does not display significant correlation effects, even though the pristine nanotube material shows a Luttinger-liquid behavior. We argue that the carbon nanotube ensemble essentially maps out the whole Brillouin zone of graphene, thus it acts as a model system of biased graphene.

  6. Monolithic three-dimensional electrochemical energy storage system on aerogel or nanotube scaffold

    Science.gov (United States)

    Farmer, Joseph C; Stadermann, Michael

    2013-11-12

    A monolithic three-dimensional electrochemical energy storage system is provided on an aerogel or nanotube scaffold. An anode, separator, cathode, and cathodic current collector are deposited on the aerogel or nanotube scaffold.

  7. Monolithic three-dimensional electrochemical energy storage system on aerogel or nanotube scaffold

    Science.gov (United States)

    Farmer, Joseph Collin; Stadermann, Michael

    2014-07-15

    A monolithic three-dimensional electrochemical energy storage system is provided on an aerogel or nanotube scaffold. An anode, separator, cathode, and cathodic current collector are deposited on the aerogel or nanotube scaffold.

  8. Excellent Formaldehyde Gas-Sensing Properties of Ruptured Nd-Doped In2O3 Porous Nanotubes

    Science.gov (United States)

    Wang, Xuesong; Li, Haiying; Ni, Mucui; Wang, Lianyuan; Liu, Li; Wang, Han; Guo, Xuexin

    2017-01-01

    The ruptured Nd-doped In2O3 porous nanotubes have been successfully synthesized by single-capillary electrospinning method. The morphologies of the as-prepared materials were characterized by scanning electron microscopy and transmission electron microscopy. It can be seen obviously that the surface of the nanotubes are distributed with cracks and pores, which formed such an open nanostructure. The crystal structures and components were determined by x-ray diffraction, energy-dispersive x-ray spectroscopy and x-ray photoelectron spectrometer. The gas-sensing properties of ruptured Nd-doped In2O3 porous nanotubes were studied and the results show the excellent performances of the as-obtained materials. The response of ruptured Nd-doped In2O3 porous nanotubes to 100 ppm of formaldehyde is 46.8 at the optimum temperature of 240°C. The response and recovery times are 8 s and 22 s, respectively. Furthermore, the lowest detection limit of formaldehyde is 100 ppb with the value of 2.4. In addition, the ruptured Nd-doped In2O3 porous nanotubes exhibit good selectivity to formaldehyde and long-term stability.

  9. Carbon Nanotubes: Printed Carbon Nanotube Electronics and Sensor Systems (Adv. Mater. 22/2016).

    Science.gov (United States)

    Chen, Kevin; Gao, Wei; Emaminejad, Sam; Kiriya, Daisuke; Ota, Hiroki; Nyein, Hnin Yin Yin; Takei, Kuniharu; Javey, Ali

    2016-06-01

    Printed electronics and sensors enable new applications ranging from low-cost disposable analytical devices to large-area sensor networks. Recent progress in printed carbon nanotube electronics in terms of materials, processing, devices, and applications is discussed on page 4397 by A. Javey and co-workers. The research challenges and opportunities regarding the processing and system-level integration are also discussed for enabling of practical applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Optimization of Magnetic Field-Assisted Synthesis of Carbon Nanotubes for Sensing Applications

    Directory of Open Access Journals (Sweden)

    Grzegorz Raniszewski

    2014-10-01

    Full Text Available One of the most effective ways of synthesizing carbon nanotubes is the arc discharge method. This paper describes a system supported by a magnetic field which can be generated by an external coil. An electric arc between two electrodes is stabilized by the magnetic field following mass flux stabilization from the anode to the cathode. In this work four constructions are compared. Different configurations of cathode and coils are calculated and presented. Exemplary results are discussed. The paper describes attempts of magnetic field optimization for different configurations of electrodes.

  11. Torsional electromechanical systems based on carbon nanotubes.

    Science.gov (United States)

    Hall, A R; Paulson, S; Cui, T; Lu, J P; Qin, L-C; Washburn, S

    2012-11-01

    Carbon nanotubes (CNTs) are among the most highly studied nanomaterials due to their unique (and intertwined) mechanical and electrical properties. Recent advances in fabrication have allowed devices to be fabricated that are capable of applying a twisting force to individual CNTs while measuring mechanical and electrical response. Here, we review major results from this emerging field of study, revealing new properties of the material itself and opening possibilities for advances in future devices.

  12. Potential applications of boron nitride nanotubes as drug delivery systems.

    Science.gov (United States)

    Ciofani, Gianni

    2010-08-01

    In recent years, there has been an explosion of research in the 'bio-nano' field, with the discovery and introduction of ever more fascinating materials for applications as drug delivery systems, sensors, transducers, and so on. The author's group, for the first time in the literature, proposed boron nitride nanotubes as a valid alternative to carbon nanotubes and other kinds of inorganic materials, because of their improved chemical properties that theoretically guarantee better stability and compatibility in a biological context. In this paper, the bio-applications of boron nitride nanotubes that have emerged in the literature are summarized, with special attention given to their exploitation as safe drug delivery and targeting carriers. Finally, the possibility of combining their physical and chemical properties is approached, highlighting the features that render these innovative nanovectors unique and exceptional candidates for many bio-applications.

  13. Natural Resource Information System. Remote Sensing Studies.

    Science.gov (United States)

    Leachtenauer, J.; And Others

    A major design objective of the Natural Resource Information System entailed the use of remote sensing data as an input to the system. Potential applications of remote sensing data were therefore reviewed and available imagery interpreted to provide input to a demonstration data base. A literature review was conducted to determine the types and…

  14. Carbon nanotubes randomly decorated with gold clusters: from nano{sup 2}hybrid atomic structures to gas sensing prototypes

    Energy Technology Data Exchange (ETDEWEB)

    Charlier, J-C; Zanolli, Z [Unite de Physico-Chimie et de Physique des Materiaux (PCPM), European Theoretical Spectroscopy Facility (ETSF), Universite Catholique de Louvain, Place Croix du Sud 1, B-1348 Louvain-la-Neuve (Belgium); Arnaud, L; Avilov, I V; Felten, A; Pireaux, J-J [Centre de Recherche en Physique de la Matiere et du Rayonnement (PMR-LISE), Facultes Universitaires Notre-Dame de la Paix, 61 Rue de Bruxelles, B-5000 Namur (Belgium); Delgado, M [Sensotran, s.l., Avenida Remolar 31, E-08820 El Prat de Llobregat, Barcelona (Spain); Demoisson, F; Reniers, F [Service de Chimie Analytique et Chimie des Interfaces (CHANI), Universite Libre de Bruxelles, Faculte des Sciences, CP255, Boulevard du Triomphe 2, B-1050 Bruxelles (Belgium); Espinosa, E H; Ionescu, R; Leghrib, R; Llobet, E [Department of Electronic Engineering, Universitat Rovira i Virgili, Avenida Paisos Catalans 26, E-43007 Tarragona (Spain); Ewels, C P; Suarez-Martinez, I [Institut des Materiaux Jean Rouxel (IMN), Universite de Nantes, 2 rue de la Houssiniere-BP 32229, F-44322 Nantes Cedex 3 (France); Guillot, J; Mansour, A; Migeon, H-N [Departement Science et Analyse des Materiaux, Centre de Recherche Public-Gabriel Lippmann, rue du Brill 41, L-4422 Belvaux (Luxembourg); Watson, G E, E-mail: jean-jacques.pireaux@fundp.ac.b [Vega Science Trust, Unit 118, Science Park SQ, Brighton, BN1 9SB (United Kingdom)

    2009-09-16

    Carbon nanotube surfaces, activated and randomly decorated with metal nanoclusters, have been studied in uniquely combined theoretical and experimental approaches as prototypes for molecular recognition. The key concept is to shape metallic clusters that donate or accept a fractional charge upon adsorption of a target molecule, and modify the electron transport in the nanotube. The present work focuses on a simple system, carbon nanotubes with gold clusters. The nature of the gold-nanotube interaction is studied using first-principles techniques. The numerical simulations predict the binding and diffusion energies of gold atoms at the tube surface, including realistic atomic models for defects potentially present at the nanotube surface. The atomic structure of the gold nanoclusters and their effect on the intrinsic electronic quantum transport properties of the nanotube are also predicted. Experimentally, multi-wall CNTs are decorated with gold clusters using (1) vacuum evaporation, after activation with an RF oxygen plasma and (2) colloid solution injected into an RF atmospheric plasma; the hybrid systems are accurately characterized using XPS and TEM techniques. The response of gas sensors based on these nano{sup 2}hybrids is quantified for the detection of toxic species like NO{sub 2}, CO, C{sub 2}H{sub 5}OH and C{sub 2}H{sub 4}.

  15. Simultaneous Adjustment of Size and Helical Sense of Chiral Nanospheres and Nanotubes Derived from an Axially Racemic Poly(phenylacetylene).

    Science.gov (United States)

    Arias, Sandra; Núñez-Martínez, Manuel; Quiñoá, Emilio; Riguera, Ricardo; Freire, Félix

    2017-01-01

    Nanospheres and nanotubes with full control of their size and helical sense are obtained in chloroform from the axially racemic chiral poly(phenylacetylene) poly-(R)-1 using either Ag(+) as both chiral inducer and cross-linking agent or Na(+) as chiral inducer and Ag(+) as cross-linking agent. The size is tuned by the polymer/ion ratio while the helical sense is modulated by the polymer/cosolvent (i.e., MeCN) ratio. In this way, the helicity and the size of the nanoparticles can be easily interconverted by very simple experimental changes.

  16. Remote Sensing Wind and Wind Shear System.

    Science.gov (United States)

    Contents: Remote sensing of wind shear and the theory and development of acoustic doppler; Wind studies; A comparison of methods for the remote detection of winds in the airport environment; Acoustic doppler system development; System calibration; Airport operational tests.

  17. Fabrication of TiO{sub 2} nanotubes by anodization of Ti thin films for VOC sensing

    Energy Technology Data Exchange (ETDEWEB)

    K Latin-Small-Letter-Dotless-I l Latin-Small-Letter-Dotless-I nc, N.; Sennik, E. [Gebze Institute of Technology, Faculty of Science, Department of Physics, 41400 Kocaeli (Turkey); Oeztuerk, Z.Z., E-mail: zozturk@gyte.edu.tr [Gebze Institute of Technology, Faculty of Science, Department of Physics, 41400 Kocaeli (Turkey); TUeBITAK-Marmara Research Center, Materials Institute, 41470 Gebze-Kocaeli (Turkey)

    2011-11-30

    Ti thin films were anodized in aqueous HF (0.5 wt.%) and in polar organic (0.5 wt.% NH{sub 4}F + ethylene glycol) electrolytes to form TiO{sub 2} nanotube arrays. Ti thin films were deposited on microscope glass substrates and then anodized. Anodization was performed at potentials ranging from 5 V to 20 V for the aqueous HF and from 20 V to 60 V for the polar organic electrolytes over the temperatures range from 0 to 20 Degree-Sign C. The TiO{sub 2} nanotubes were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). It has been observed that anodization of the deposited Ti thin films with aqueous HF solution at 0 Degree-Sign C resulted in nanotube-type structures with diameters in the range of 30-80 nm for an applied voltage of 10 V. In addition, the nanotube-type structure is observed for polar organic electrolyte at room temperature at the anodization voltage higher than 40 V. The volatile organic compound (VOC) sensing properties of TiO{sub 2} nanotubes fabricated using different electrolytes were investigated at 200 Degree-Sign C. The maximum sensor response is obtained for carbon tetrachloride. The sensor response is dependent on porosity of TiO{sub 2}. The highest sensor response is observed for TiO{sub 2} nanotubes which are synthesized using aqueous HF electrolyte and have very high porosity.

  18. Putative Nitrogen Sensing Systems in Higher Plants

    Institute of Scientific and Technical Information of China (English)

    Hon-Ming Lam; Ying Ann Chiao; Man-Wah Li; Yuk-Kwong Yung; Sang Ji

    2006-01-01

    Nitrogen (N) metabolism is essential for the biosynthesis of vital biomolecules. N status thus exerts profound effects on plant growth and development, and must be closely monitored. In bacteria and fungi, a few sophisticated N sensing systems have been extensively studied. In animals, the ability to receive amino acid signals has evolved to become an integral part of the nervous coordination system. In this review, we will summarize recent developments in the search for putative N sensing systems in higher plants based on homologous systems in bacteria, fungi, and animals. Apparently, although plants have separated and diversified from other organisms during the evolution process, striking similarities can be found in their N sensing systems compared with those of their counterparts; however, our understanding of these systems is still incomplete. Significant modifications of the N sensing systems (including cross-talk with other signal transduction pathways) in higher plants may be a strategy of adaptation to their unique mode of life.

  19. Strain Sensing Characteristics of Rubbery Carbon Nanotube Composite for Flexible Sensors.

    Science.gov (United States)

    Choi, Gyong Rak; Park, Hyung-ki; Huh, Hoon; Kim, Young-Ju; Ham, Heon; Kim, Hyoun Woo; Lim, Kwon Taek; Kim, Sung Yong; Kang, Inpil

    2016-02-01

    In this study, the piezoresistive properties of CNT (Carbon Nanotube)/EPDM composite are characterized for the applications of a flexible sensor. The CNT/EPDM composites were prepared by using a Brabender mixer with MWCNT (Multi-walled Carbon Nanotube) and organoclay. The static and quasi-dynamic voltage output responses of the composite sensor were also experimentally studied and were compared with those of a conventional foil strain gage. The voltage output by using a signal processing system was fairly stable and it shows somehow linear responses at both of loading and unloading cases with hysteresis. The voltage output was distorted under a quasi-dynamic test due to its unsymmetrical piezoresistive characteristics. The CNT/EPDM sensor showed quite tardy response to its settling time test under static deflections and that would be a hurdle for its real time applications. Furthermore, since the CNT/EPDM sensor does not have directional voltage output to tension and compression, it only could be utilized as a mono-directional force sensor such as a compressive touch sensor.

  20. Dynamical response of multi-walled carbon nanotube resonators based on continuum mechanics modeling for mass sensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Myungseok; Olshevskiy, Alexander; Kim, Chang-Wan [Konkuk University, Seoul (Korea, Republic of); Eom, Kilho [Sungkyunkwan University, Suwon (Korea, Republic of); Gwak, Kwanwoong [Sejong University, Seoul (Korea, Republic of); Dai, Mai Duc [Ho Chi Minh City University of Technology and Education, Ho Chi Minh (Viet Nam)

    2017-05-15

    Carbon nanotube (CNT) has recently received much attention due to its excellent electromechanical properties, indicating that CNT can be employed for development of Nanoelectromechanical system (NEMS) such as nanomechanical resonators. For effective design of CNT-based resonators, it is required to accurately predict the vibration behavior of CNT resonators as well as their frequency response to mass adsorption. In this work, we have studied the vibrational behavior of Multi-walled CNT (MWCNT) resonators by using a continuum mechanics modeling that was implemented in Finite element method (FEM). In particular, we consider a transversely isotropic hollow cylinder solid model with Finite element (FE) implementation for modeling the vibration behavior of Multi-walled CNT (MWCNT) resonators. It is shown that our continuum mechanics model provides the resonant frequencies of various MWCNTs being comparable to those obtained from experiments. Moreover, we have investigated the frequency response of MWCNT resonators to mass adsorption by using our continuum model with FE implementation. Our study sheds light on our continuum mechanics model that is useful in predicting not only the vibration behavior of MWCNT resonators but also their sensing performance for further effective design of MWCNT- based NEMS devices.

  1. Development of a paper-based carbon nanotube sensing microfluidic device for biological detection.

    Science.gov (United States)

    Yang, Shih-I; Lei, Kin Fong; Tsai, Shiao-Wen; Hsu, Hsiao-Ting

    2013-01-01

    Carbon nanotube (CNT) has been utilized for the biological detection due to its extremely sensitive to biological molecules. A paper-based CNT sensing microfluidic device has been developed for the detection of protein, i.e., biotin-avidin, binding. We have developed a fabrication method that allows controlled deposition of bundled CNTs with well-defined dimensions to form sensors on paper. Then, polydimethyl siloxane (PDMS) was used to pattern the hydrophobic boundary on paper to form the reaction sites. The proposed fabrication method is based on vacuum filtration process with a metal mask covering on a filter paper for the definition of the dimension of sensor. The length, width, and thickness of the CNT-based sensors are readily controlled by the metal mask and the weight of the CNT powder used during the filtration process, respectively. Homogeneous deposition of CNTs with well-defined dimensions can be achieved. The CNT-based sensor on paper has been demonstrated on the detection of the protein binding. Biotin was first immobilized on the CNT's sidewall and avidin suspended solution was applied to the site. The result of the biotin-avidin binding was measured by the resistance change of the sensor, which is a label-free detection method. It showed the CNT is sensitive to the biological molecules and the proposed paper-based CNT sensing device is a possible candidate for point-of-care biosensors. Thus, electrical bio-assays on paper-based microfluidics can be realized to develop low cost, sensitive, and specific diagnostic devices.

  2. Gas sensitivity and sensing mechanism studies on Au-doped TiO₂ nanotube arrays for detecting SF₆ decomposed components.

    Science.gov (United States)

    Zhang, Xiaoxing; Yu, Lei; Tie, Jing; Dong, Xingchen

    2014-10-17

    The analysis to SF6 decomposed component gases is an efficient diagnostic approach to detect the partial discharge in gas-insulated switchgear (GIS) for the purpose of accessing the operating state of power equipment. This paper applied the Au-doped TiO2 nanotube array sensor (Au-TiO2 NTAs) to detect SF6 decomposed components. The electrochemical constant potential method was adopted in the Au-TiO2 NTAs' fabrication, and a series of experiments were conducted to test the characteristic SF6 decomposed gases for a thorough investigation of sensing performances. The sensing characteristic curves of intrinsic and Au-doped TiO2 NTAs were compared to study the mechanism of the gas sensing response. The results indicated that the doped Au could change the TiO2 nanotube arrays' performances of gas sensing selectivity in SF6 decomposed components, as well as reducing the working temperature of TiO2 NTAs.

  3. An Integrated System for Wildlife Sensing

    Science.gov (United States)

    2014-08-14

    System for Wildlife Sensing (x) Material has been given an OPSEC review and it has been determined to be non sensitive and, except for manuscripts and...System for Wildlife Sensing The views, opinions and/or findings contained in this report are those of the author(s) and should not contrued as an...ADDRESS (ES) U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 Infrared camera, FLIR, Android, Wildlife Management

  4. A sensing mechanism for the detection of carbon nanotubes using selective photoluminescent probes based on ionic complexes with organic dyes

    Institute of Scientific and Technical Information of China (English)

    Petro Lutsyk; Raz Arif; Jan Hruby; Anatolii Bukivskyi; Olexander Vinijchuk; Mykola Shandura; Viktor Yakubovskyi

    2016-01-01

    The multifunctional properties of carbon nanotubes (CNTs) make them a powerful platform for unprecedented innovations in a variety of practical applications.As a result of the surging growth of nanotechnology,nanotubes present a potential problem as an environmental pollutant,and as such,an efficient method for their rapid detection must be established.Here,we propose a novel type of ionic sensor complex for detecting CNTs-an organic dye that responds sensitively and selectively to CNTs with a photoluminescent signal.The complexes are formed through Coulomb attractions between dye molecules with uncompensated charges and CNTs covered with an ionic surfactant in water.We demonstrate that the photoluminescent excitation of the dye can be transferred to the nanotubes,resulting in selective and strong amplification (up to a factor of 6) of the light emission from the excitonic levels of CNTs in the near-infrared spectral range,as experimentally observed via excitation-emission photoluminescence (PL) mapping.The chirality of the nanotubes and the type of ionic surfactant used to disperse the nanotubes both strongly affect the amplification;thus,the complexation provides sensing selectivity towards specific CNTs.Additionally,neither similar uncharged dyes nor CNTs covered with neutral surfactant form such complexes.As model organic molecules,we use a family of pelymethine dyes with an easily tailorable molecular structure and,consequently,tunable absorbance and PL characteristics.This provides us with a versatile tool for the controllable photonic and electronic engineering of an efficient probe for CNT detection.

  5. System-Level Design Considerations for Carbon Nanotube Electromechanical Resonators

    Directory of Open Access Journals (Sweden)

    Christian Kauth

    2013-01-01

    Full Text Available Despite an evermore complete plethora of complex domain-specific semiempirical models, no succinct recipe for large-scale carbon nanotube electromechanical systems design has been formulated. To combine the benefits of these highly sensitive miniaturized mechanical sensors with the vast functionalities available in electronics, we identify a reduced key parameter set of carbon nanotube properties, nanoelectromechanical system design, and operation that steers the sensor’s performance towards system applications, based on open- and closed-loop topologies. Suspended single-walled carbon nanotubes are reviewed in terms of their electromechanical properties with the objective of evaluating orders of magnitude of the electrical actuation and detection mechanisms. Open-loop time-averaging and 1ω or 2ω mixing methods are completed by a new 4ω actuation and detection technique. A discussion on their extension to closed-loop topologies and system applications concludes the analysis, covering signal-to-noise ratio, and the capability to spectrally isolate the motional information from parasitical feedthrough by contemporary electronic read-out techniques.

  6. Space remote sensing systems an introduction

    CERN Document Server

    Chen, H S

    1985-01-01

    Space Remote Sensing Systems: An Introduction discusses the space remote sensing system, which is a modern high-technology field developed from earth sciences, engineering, and space systems technology for environmental protection, resource monitoring, climate prediction, weather forecasting, ocean measurement, and many other applications. This book consists of 10 chapters. Chapter 1 describes the science of the atmosphere and the earth's surface. Chapter 2 discusses spaceborne radiation collector systems, while Chapter 3 focuses on space detector and CCD systems. The passive space optical rad

  7. Carbon nanotube switches for memory, RF communications and sensing applications, and methods of making the same

    Science.gov (United States)

    Kaul, Anupama B. (Inventor); Wong, Eric W. (Inventor); Baron, Richard L. (Inventor); Epp, Larry (Inventor)

    2008-01-01

    Switches having an in situ grown carbon nanotube as an element thereof, and methods of fabricating such switches. A carbon nanotube is grown in situ in mechanical connection with a conductive substrate, such as a heavily doped silicon wafer or an SOI wafer. The carbon nanotube is electrically connected at one location to a terminal. At another location of the carbon nanotube there is situated a pull electrode that can be used to elecrostatically displace the carbon nanotube so that it selectively makes contact with either the pull electrode or with a contact electrode. Connection to the pull electrode is sufficient to operate the device as a simple switch, while connection to a contact electrode is useful to operate the device in a manner analogous to a relay. In various embodiments, the devices disclosed are useful as at least switches for various signals, multi-state memory, computational devices, and multiplexers.

  8. Electrically conductive strain sensing polyurethane nanocomposites with synergistic carbon nanotubes and graphene bifillers

    Science.gov (United States)

    Liu, Hu; Gao, Jiachen; Huang, Wenju; Dai, Kun; Zheng, Guoqiang; Liu, Chuntai; Shen, Changyu; Yan, Xingru; Guo, Jiang; Guo, Zhanhu

    2016-06-01

    Thermoplastic polyurethane (TPU) based conductive polymer composites (CPCs) with a reduced percolation threshold and tunable resistance-strain sensing behavior were obtained through the addition of synergistic carbon nanotubes (CNT) and graphene bifillers. The percolation threshold of graphene was about 0.006 vol% when the CNT content was fixed at 0.255 vol% that is below the percolation threshold of CNT/TPU nanocomposites. The synergistic effect between graphene and CNT was identified using the excluded volume theory. Graphene acted as a `spacer' to separate the entangled CNTs from each other and the CNT bridged the broad gap between individual graphene sheets, which was beneficial for the dispersion of CNT and formation of effective conductive paths, leading to better electrical conductivity at a lower conductive filler content. Compared with the dual-peak response pattern of the CNT/TPU based strain sensors, the CPCs with hybrid conductive fillers displayed single-peak response patterns under small strain, indicating good tunability with the synergistic effect of CNT and graphene. Under larger strain, prestraining was adopted to regulate the conductive network, and better tunable single-peak response patterns were also obtained. The CPCs also showed good reversibility and reproductivity under cyclic extension. This study paves the way for the fabrication of CPC based strain sensors with good tunability.Thermoplastic polyurethane (TPU) based conductive polymer composites (CPCs) with a reduced percolation threshold and tunable resistance-strain sensing behavior were obtained through the addition of synergistic carbon nanotubes (CNT) and graphene bifillers. The percolation threshold of graphene was about 0.006 vol% when the CNT content was fixed at 0.255 vol% that is below the percolation threshold of CNT/TPU nanocomposites. The synergistic effect between graphene and CNT was identified using the excluded volume theory. Graphene acted as a `spacer' to separate the

  9. Embedded Aligned Carbon Nanotube Sheets for Strain and Damage sensing in Composite Structures

    Science.gov (United States)

    Aly, Karim Aly Abdelomoaty Elsayed

    The world demand for fiber reinforced composite materials has been steadily increasing because of the widespread adoption of this class of material in many markets. The automotive, aerospace, marine and energy sectors account for a large percentage of this grow. Outstanding fatigue performance, high specific stiffness and strength, and low density are among the most important properties that fiber reinforced polymer composites offer. Furthermore, their properties can be tailored to meet the specific needs of the final applications. However, this class of material is composed of multiple layers of inhomogeneous and anisotropic constituents, i.e. fibers and matrix. Therefore, this laminated nature make the composite material prone to intrinsic damage including interfacial debonding and delamination and their strength and failure are dependent on the fiber architecture and direction of the applied stresses. Consequently, it is of prime importance to monitor the health of these structures. New and improved methods for early detection of damage and structural health monitoring of composite materials may allow for enhanced reliability, lifetime and performance while minimizing maintenance time during a composite part's service life. Over the last few decades different non-destructive methods and materials have been investigated for use as strain sensors. Since the discovery of carbon nanotubes (CNTs), they have attracted much research interest due to their superior electrical, thermal and mechanical properties as well as their high aspect ratio. In this context, CNTs have been used in the recent years to enable sensing capabilities. In this dissertation, the usage of CNTs for performing strain and damage sensing in composites is evaluated. This was enabled by embedding aligned sheets of two millimeters long, interconnected CNTs into laminated structures that were then subjected to different forms of mechanical loading. The localization of the CNT sheets inside the host

  10. A Bio-Inspired Two-Layer Sensing Structure of Polypeptide and Multiple-Walled Carbon Nanotube to Sense Small Molecular Gases

    Directory of Open Access Journals (Sweden)

    Li-Chun Wang

    2015-03-01

    Full Text Available In this paper, we propose a bio-inspired, two-layer, multiple-walled carbon nanotube (MWCNT-polypeptide composite sensing device. The MWCNT serves as a responsive and conductive layer, and the nonselective polypeptide (40 mer coating the top of the MWCNT acts as a filter into which small molecular gases pass. Instead of using selective peptides to sense specific odorants, we propose using nonselective, peptide-based sensors to monitor various types of volatile organic compounds. In this study, depending on gas interaction and molecular sizes, the randomly selected polypeptide enabled the recognition of certain polar volatile chemical vapors, such as amines, and the improved discernment of low-concentration gases. The results of our investigation demonstrated that the polypeptide-coated sensors can detect ammonia at a level of several hundred ppm and barely responded to triethylamine.

  11. Preparation of Multiwalled Carbon Nanotube-Poly (4-Styrenesulfonic Acid Aqueous Dispersion for Dopamine Sensing

    Directory of Open Access Journals (Sweden)

    Aihua LIU

    2006-12-01

    Full Text Available A simple and facile method for the non-covalent functionalization of multi-walled carbon nanotubes (MWNTs using poly(4-styrenesulfonic acid (PSS is proposed. The resulting PSS-MWNTs dispersion is readily soluble in water and can be left to stand for 2 weeks at room temperature, no phase separation with aggregation of nanotubes at the bottom of the vials was observed. The as-prepared PSS-MWNTs dispersions could facilitate the processing of the nanotubes into composites with high nanotube loading. The PSS-MWNTs complex shows high electrocatalytic activity to the oxidation of neutrontransmitter of dopamine, suggesting that the coating of PSS onto carbon nanotubes surface without destroying the electronic structures of the pristine carbon nanotubes; therefore, the unique properties including the catalytic property of the nanotubes retained. It is envisioned that the PSS-MWNTs aqueous dispersions may find possible applications in the development of biosensors, bioelectronics, separation and environment protection as well as other biological events where water-based environment is required.

  12. Doping effect of In{sub 2}O{sub 3} on structural and ethanol-sensing characteristics of ZnO nanotubes fabricated by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Baoyu; Zhao, Changhui; Zhang, Mingxiang; Zhang, Zemin; Xie, Erqing, E-mail: xieeq@lzu.edu.cn; Zhou, Jinyuan, E-mail: zhoujy@lzu.edu.cn; Han, Weihua

    2015-09-15

    Highlights: • IZO nanotubes with various indium contents were synthesized by electrospinning. • A well-crystallized indium-zinc-oxide solid solution formed in IZO-0.01 nanotubes. • Amorphous In{sub 2}O{sub 3} segregated at ZnO grain boundaries at high indium doping levels. • IZO-0.01 nanotubes show a high response and good selectivity to ethanol at 275 °C. - Abstract: Indium-doped ZnO (IZO) nanotubes with various indium contents (0.01–0.20) were synthesized via a facile electrospinning method. Results of X-ray diffraction and transmission electron microscopy demonstrate that all samples are consisted of hexagonal wurtzite-typed ZnO, showing a well-crystallized indium-zinc-oxide solid solution when only a small amount of zinc ions substituted by indium ions (0.01). Once the amount of indium dopants ≥0.05, there will form some amorphous In{sub 2}O{sub 3}, leading to a pronounced decrease in grain sizes. Gas-sensing performances revealed that the IZO nanotube-based sensors have enhanced ethanol-sensing characteristics, especially, sensor based on IZO-0.01 nanotubes shows the highest response (R{sub a}/R{sub g} = 81.7), which is twice that of the undoped ZnO nanotubes (40.0) toward 100 ppm ethanol at an operating temperature of 275 °C. And IZO-0.20 nanotube-based sensor presents a relatively high response at high ethanol concentrations. Our research suggested that these remarkable enhanced ethanol-sensing properties can be closely related to the formation of indium-zinc-oxide solid solutions and/or heterostructures between ZnO and amorphous In{sub 2}O{sub 3}.

  13. Enhancement of Gas Sensing Characteristics of Multiwalled Carbon Nanotubes by CF4 Plasma Treatment for SF6 Decomposition Component Detection

    Directory of Open Access Journals (Sweden)

    Xiaoxing Zhang

    2015-01-01

    Full Text Available H2S and SO2 are important gas components of decomposed SF6 of partial discharge generated by insulation defects in gas-insulated switchgear (GIS. Therefore, H2S and SO2 detection is important in the state evaluation and fault diagnosis of GIS. In this study, dielectric barrier discharge was used to generate CF4 plasma and modify multiwalled carbon nanotubes (MWNTs. The nanotubes were plasma-treated at optimum discharge conditions under different treatment times (0.5, 1, 2, 5, 8, 10, and 12 min. Pristine and treated MWNTs were used as gas sensors to detect H2S and SO2. The effects of treatment time on gas sensitivity were analyzed. Results showed that the sensitivity, response, and recovery time of modified MWNTs to H2S were improved, but the recovery time of SO2 was almost unchanged. At 10 min treatment time, the MWNTs showed good stability and reproducibility with better gas sensing properties compared with the other nanotubes.

  14. Poster Abstract: Towards a Categorization Framework for Occupancy Sensing Systems

    DEFF Research Database (Denmark)

    Kjærgaard, Mikkel Baun; Lazarova-Molnar, Sanja; Jradi, Muhyiddine

    2015-01-01

    on occupancy sensing systems goes beyond basic methods, there is an increasing need for better comparison of proposed occupancy sensing systems. Developers of occupancy sensing systems are also lacking good frameworks for understanding different options when building occupancy sensing systems. This poster...

  15. Electrodeposition of gold-platinum alloy nanoparticles on carbon nanotubes as electrochemical sensing interface for sensitive detection of tumor marker

    Energy Technology Data Exchange (ETDEWEB)

    Li Ya [Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Yuan Ruo, E-mail: yuanruo@swu.edu.cn [Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Chai Yaqin; Song Zhongju [Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China)

    2011-07-30

    Graphical abstract: Electrodeposition of gold-platinum alloy (Au-PtNPs) on carbon nanotubes as electrochemical sensing interface and HRP as blocking agent for the fabrication of high sensitive immunosensor. Display Omitted Highlights: > In this work, we proposed a novel electrochemical sensing surface. > The sensing surface possessed larger electro-active areas and higher conductivity due to the introduction of MWCNTs. > The signal could be amplified effectively by synergetic catalysis effect of Au-PtNPs and HRP towards the reduction of H{sub 2}O{sub 2}. > Biomolecules could be immobilized on the surface of Au-PtNPs tightly with the bioactivity kept well. > The simple fabrication method provided a new potential for the future development of practical devices for clinical diagnosis application. - Abstract: A novel electrochemical sensing interface, electrodeposition of gold-platinum alloy nanoparticles (Au-PtNPs) on carbon nanotubes, was proposed and used to fabricate a label-free amperometric immunosensor. On the one hand, the multiwalled carbon nanotubes (MWCNTs) could increase active area of the electrode and enhance the electron transfer ability between the electrode and redox probe; on the other hand, the Au-PtNPs not only could be used to assemble biomolecules with bioactivity kept well, but also could further facilitate the shuttle of electrons. In the meanwhile, horseradish peroxidase (HRP) instead of bovine serum albumin (BSA) was employed to block the possible remaining active sites and avoid the nonspecific adsorption. With the synergetic catalysis effect of Au-PtNPs and HRP towards the reduction of hydrogen peroxide (H{sub 2}O{sub 2}), the signal could be amplified and the sensitivity could be enhanced. Using alpha-fetoprotein (AFP) as model analyte, the fabricated immunosensor exhibited two wide linear ranges in the concentration ranges of 0.5-20 ng mL{sup -1} and 20-200 ng mL{sup -1} with a detection limit of 0.17 ng mL{sup -1} at a signal-to-noise of

  16. [Odor sensing system and olfactory display].

    Science.gov (United States)

    Nakamoto, Takamichi

    2014-01-01

    In this review, an odor sensing system and an olfactory display are introduced into people in pharmacy. An odor sensing system consists of an array of sensors with partially overlapping specificities and pattern recognition technique. One of examples of odor sensing systems is a halitosis sensor which quantifies the mixture composition of three volatile sulfide compounds. A halitosis sensor was realized using a preconcentrator to raise sensitivity and an electrochemical sensor array to suppress the influence of humidity. Partial least squares (PLS) method was used to quantify the mixture composition. The experiment reveals that the sufficient accuracy was obtained. Moreover, the olfactory display, which present scents to human noses, is explained. A multi-component olfactory display enables the presentation of a variety of smells. The two types of multi-component olfactory display are described. The first one uses many solenoid valves with high speed switching. The valve ON frequency determines the concentration of the corresponding odor component. The latter one consists of miniaturized liquid pumps and a surface acoustic wave (SAW) atomizer. It enables the wearable olfactory display without smell persistence. Finally, the application of the olfactory display is demonstrated. Virtual ice cream shop with scents was made as a content of interactive art. People can enjoy harmony among vision, audition and olfaction. In conclusion, both odor sensing system and olfactory display can contribute to the field of human health care.

  17. Systems and Methods for Implementing Robust Carbon Nanotube-Based Field Emitters

    Science.gov (United States)

    Manohara, Harish (Inventor); Kristof, Valerie (Inventor); Toda, Risaku (Inventor)

    2015-01-01

    Systems and methods in accordance with embodiments of the invention implement carbon nanotube-based field emitters. In one embodiment, a method of fabricating a carbon nanotube field emitter includes: patterning a substrate with a catalyst, where the substrate has thereon disposed a diffusion barrier layer; growing a plurality of carbon nanotubes on at least a portion of the patterned catalyst; and heating the substrate to an extent where it begins to soften such that at least a portion of at least one carbon nanotube becomes enveloped by the softened substrate.

  18. Self-assembly of J-aggregate nanotubes and their applications for sensing dopamine.

    Science.gov (United States)

    Liang, Weilang; He, Sihui; Fang, Jiyu

    2014-01-28

    J-aggregates are an attractive supramolecular structure with interesting excitation properties found in the light-harvesting antenna of green sulfur bacteria. To structurally mimic the light-harvesting antenna, we synthesize J-aggregate nanotubes with a sharp and intense absorption band (J-band) by the coassembly of lithocholic acid (LCA) and 3,3'-dipropylthiadicarbocyanine iodide (DiSC3(5)) in aqueous solution. We show that the J-aggregate nanotubes can be used as a supramolecular probe for the sensitive and selective detection of dopamine (DA) in phosphate buffered saline (PBS) solution with the detection limit of ∼0.4 nM by simply observing the intensity change of the J-band due to the efficient photoinduced electron transfer from the J-aggregate nanotubes to the adsorbed DA.

  19. Design and Development of an Acoustic Levitation System for Use in CVD Growth of Carbon Nanotubes

    Science.gov (United States)

    Qasem, Amal ali

    produce the standing waves. The levitation of small Styrofoam balls was successful by using this system and verified wavelengths of standing wave and position of levitation. We could not levitate powders, most likely due to electrostatic charging, air currents, but most importantly insufficient power to drive transducer. In addition, we built a CVD growth furnace with ultrasound transducer- horn- quartz rod and reflector. The reflector support also included a sense piezoelectric element for determining standing wave strength. This reflector support was mounted on a linear translation stage to control the quartz rod-reflector separation to produce standing waves. To remove the contaminated unwanted CNTs, we built a separate tube furnace tube filled with a molecular sieve to burn the CNT's in air. Finally, we made catalyst-coated, ceramic microparticles for levitation and used these to verify CNT growth. Future efforts research would be to levitate these micro particles at room temperature then in the high temperature furnace for growth of carbon nanotubes.

  20. The immune system as the sixth sense.

    Science.gov (United States)

    Blalock, J E

    2005-02-01

    One of the truly remarkable discoveries in modern biology is the finding that the nervous system and immune system use a common chemical language for intra- and inter-system communication. This review will discuss some of the pivotal results that deciphered this chemical language. Specifically the nervous and immune systems produce a common set of peptide and nonpeptide neurotransmitters and cytokines that act on a common repertoire of receptors in the two systems. The paper will also review more recent studies that have delineated hardwired and humoral pathways for such bidirectional communication. This is discussed in the context of the idea that the sharing of ligands and receptors allows the immune system to serve as the sixth sense that notifies the nervous system of the presence of entities, such as viruses and bacteria, that are imperceptible to the classic senses. Lastly, this review will suggest ways to apply the newfound knowledge of the sixth sense to understand a placebo effect and to treat human disease.

  1. Intelligent hand-portable proliferation sensing system

    Energy Technology Data Exchange (ETDEWEB)

    Dieckman, S.L.; Bostrom, G.A.; Waterfield, L.G.; Jendrzejczyk, J.A.; Ahuja, S.; Raptis, A.C.

    1997-08-01

    Argonne National Laboratory, with support from DOE`s Office of Nonproliferation and National Security, is currently developing an intelligent hand-portable sensor system. This system is designed specifically to support the intelligence community with the task of in-field sensing of nuclear proliferation and related activities. Based upon pulsed laser photo-ionization time-of-flight mass spectrometry technology, this novel sensing system is capable of quickly providing a molecular or atomic analysis of specimens. The system is capable of analyzing virtually any gas phase molecule, or molecule that can be induced into the gas phase by (for example) sample heating. This system has the unique advantages of providing unprecedented portability, excellent sensitivity, tremendous fieldability, and a high performance/cost ratio. The system will be capable of operating in a highly automated manner for on-site inspections, and easily modified for other applications such as perimeter monitoring aboard a plane or drone. The paper describes the sensing system.

  2. Single-walled and multi-walled carbon nanotubes based drug delivery system: Cancer therapy: A review

    OpenAIRE

    Dineshkumar, B.; Krishnakumar, K; A R Bhatt; D Paul; Cherian, J; John, A.; S. Suresh

    2015-01-01

    Carbon nanotubes (CNTs) are advanced nano-carrier for delivery of drugs especially anti-cancer drugs. In the field of CNT-based drug delivery system, both single-walled carbon nanotubes (SWCNTs) and multi-walled nanotubes (MWCNTs) can be used for targeting anticancer drugs in tissues and organs, where the high therapeutic effect is necessary. Benefits of the carbon nanotubes (CNTs) in drug delivery systems are; avoiding solvent usage and reducing the side effects. Therefore, the present revie...

  3. Ultra Small Integrated Optical Fiber Sensing System

    Directory of Open Access Journals (Sweden)

    Peter Van Daele

    2012-09-01

    Full Text Available This paper introduces a revolutionary way to interrogate optical fiber sensors based on fiber Bragg gratings (FBGs and to integrate the necessary driving optoelectronic components with the sensor elements. Low-cost optoelectronic chips are used to interrogate the optical fibers, creating a portable dynamic sensing system as an alternative for the traditionally bulky and expensive fiber sensor interrogation units. The possibility to embed these laser and detector chips is demonstrated resulting in an ultra thin flexible optoelectronic package of only 40 μm, provided with an integrated planar fiber pigtail. The result is a fully embedded flexible sensing system with a thickness of only 1 mm, based on a single Vertical-Cavity Surface-Emitting Laser (VCSEL, fiber sensor and photodetector chip. Temperature, strain and electrodynamic shaking tests have been performed on our system, not limited to static read-out measurements but dynamically reconstructing full spectral information datasets.

  4. LED-Based Colour Sensing System

    Directory of Open Access Journals (Sweden)

    Ibrahim AL-BAHADLY

    2010-03-01

    Full Text Available This paper presents a new colour sensing system for measuring the colour of car paint accurately enough to reproduce the paint proportions to cover up scratches or wear on a car. The aim is to repaint a car’s damaged area at a fraction of the cost of repainting the whole car. The proposed colour sensing system is based on Light Emitting Diode (LED. A prototype for the system has been designed, built, and tested. During this work light was researched as well as lighting sources, how light travels, how light reflects and refracts, ways light can be quantized, the human eye, why cameras look accurate, lighting conditions and their effects, and the emergence of colour.

  5. Advanced Composite Armor: In Situ Sensing with Carbon Nanotube Networks for Improved Damage Tolerance

    Science.gov (United States)

    2013-08-19

    containing carbon nanotubes using VARTM before resin infusion. We found that both methods achieved electrical percolation however the fiber sizing agent...agent and epoxy resin were applied using VARTM methodology. In order to evaluate the response of thick-section composites (0.35 in/8.9 mm) under dynamic

  6. A dioxaborine cyanine dye as a photoluminescence probe for sensing carbon nanotubes

    Science.gov (United States)

    Lutsyk, Petro; Verbitsky, Anatoly; Piryatinski, Yuri; Shandura, Mykola

    2016-01-01

    The unique properties of carbon nanotubes have made them the material of choice for many current and future industrial applications. As a consequence of the increasing development of nanotechnology, carbon nanotubes show potential threat to health and environment. Therefore, development of efficient method for detection of carbon nanotubes is required. In this work, we have studied the interaction of indopentamethinedioxaborine dye (DOB-719) and single-walled carbon nanotubes (SWNTs) using absorption and photoluminescence (PL) spectroscopy. In the mixture of the dye and the SWNTs we have revealed new optical features in the spectral range of the intrinsic excitation of the dye due to resonance energy transfer from DOB-719 to SWNTs. Specifically, we have observed an emergence of new PL peaks at the excitation wavelength of 735 nm and a redshift of the intrinsic PL peaks of SWNT emission (up to 40 nm) in the near-infrared range. The possible mechanism of the interaction between DOB-719 and SWNTs has been proposed. Thus, it can be concluded that DOB-719 dye has promising applications for designing efficient and tailorable optical probes for the detection of SWNTs. PMID:28144547

  7. Heating-Rate-Triggered Carbon-Nanotube-based 3-Dimensional Conducting Networks for a Highly Sensitive Noncontact Sensing Device

    KAUST Repository

    Tai, Yanlong

    2016-01-28

    Recently, flexible and transparent conductive films (TCFs) are drawing more attention for their central role in future applications of flexible electronics. Here, we report the controllable fabrication of TCFs for moisture-sensing applications based on heating-rate-triggered, 3-dimensional porous conducting networks through drop casting lithography of single-walled carbon nanotube (SWCNT)/poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS) ink. How ink formula and baking conditions influence the self-assembled microstructure of the TCFs is discussed. The sensor presents high-performance properties, including a reasonable sheet resistance (2.1 kohm/sq), a high visible-range transmittance (>69%, PET = 90%), and good stability when subjected to cyclic loading (>1000 cycles, better than indium tin oxide film) during processing, when formulation parameters are well optimized (weight ratio of SWCNT to PEDOT:PSS: 1:0.5, SWCNT concentration: 0.3 mg/ml, and heating rate: 36 °C/minute). Moreover, the benefits of these kinds of TCFs were verified through a fully transparent, highly sensitive, rapid response, noncontact moisture-sensing device (5 × 5 sensing pixels).

  8. Development of a Carbon Nanotube-Based Touchscreen Capable of Multi-Touch and Multi-Force Sensing

    Directory of Open Access Journals (Sweden)

    Wonhyo Kim

    2015-11-01

    Full Text Available A force sensing touchscreen, which detects touch point and touch force simultaneously by sensing a change in electric capacitance, was designed and fabricated. It was made with single-walled carbon nanotubes (SWCNTs which have better mechanical and chemical characteristics than the indium-tin-oxide transparent electrodes used in most contemporary touchscreen devices. The SWCNTs, with a transmittance of about 85% and electric conductivity of 400 Ω per square; were coated and patterned on glass and polyethyleneterephthalate (PET film substrates. The constructed force sensing touchscreen has a total size and thickness of 62 mm × 100 mm × 1.4 mm, and is composed of 11 driving line and 19 receiving line channels. The gap between the channels was designed to be 20 µm, taking visibility into consideration, and patterned by a photolithography and plasma etching processes. The mutual capacitance formed by the upper and lower transparent electrodes was initially about 2.8 pF and, on applying a 500 gf force with a 3 mm diameter tip, it showed a 25% capacitance variation. Furthermore, the touchscreen can detect multiple touches and forces simultaneously and is unaffected by touch material characteristics, such as conductance or non-conductance.

  9. An effective electrical sensing scheme using AC electrothermal flow on a biosensor platform based on a carbon nanotube network

    Science.gov (United States)

    Lee, Won Cheol; Lee, Hoseok; Lim, Jaeheung; Park, Young June

    2016-11-01

    We report a simple and efficient electrical sensing scheme that can be used to overcome the "diffusion limit" of affinity-based biosensors by incorporating the structural advantage of a concentric electrode biosensor platform and the microstirring effect of AC electrothermal flow (ACEF). To prove the effect of ACEF on the biosensor performance, we performed both simulations and experiments for the detection of cardiac troponin-I, which is a biomarker for acute myocardial infarction. The finite element simulation results indicate that AC bias to the electrode (which has a concentric structure in our device) can induce fast convection flow, which facilitates the transport of the target molecules to the binding region located between the two electrodes. In our device, the channel region made of a carbon nanotube network decorated with gold nanoparticles, which act as the attaching sites of the probe molecules, is used as a highly sensitive electrical channel. We find that the electrical sensing method exhibited extremely fast sensing speeds compared with those under no bias (diffusion-limited) conditions.

  10. Flexible Transparent Films Based on Nanocomposite Networks of Polyaniline and Carbon Nanotubes for High-Performance Gas Sensing.

    Science.gov (United States)

    Wan, Pengbo; Wen, Xuemei; Sun, Chaozheng; Chandran, Bevita K; Zhang, Han; Sun, Xiaoming; Chen, Xiaodong

    2015-10-28

    A flexible, transparent, chemical gas sensor is assembled from a transparent conducting film of carbon nanotube (CNT) networks that are coated with hierarchically nanostructured polyaniline (PANI) nanorods. The nanocomposite film is synthesized by in-situ, chemical oxidative polymerization of aniline in a functional multiwalled CNT (FMWCNT) suspension and is simultaneously deposited onto a flexible polyethylene terephthalate (PET) substrate. An as-prepared flexible transparent chemical gas sensor exhibits excellent transparency of 85.0% at 550 nm using the PANI/FMWCNT nanocomposite film prepared over a reaction time of 8 h. The sensor also shows good flexibility, without any obvious decrease in performance after 500 bending/extending cycles, demonstrating high-performance, portable gas sensing at room temperature. This superior performance could be attributed to the improved electron transport and collection due to the CNTs, resulting in reliable and efficient sensing, as well as the high surface-to-volume ratio of the hierarchically nanostructured composites. The excellent transparency, improved sensing performance, and superior flexibility of the device, may enable the integration of this simple, low-cost, gas sensor into handheld flexible transparent electronic circuitry and optoelectronic devices.

  11. Remote shock sensing and notification system

    Science.gov (United States)

    Muralidharan, Govindarajan; Britton, Charles L.; Pearce, James; Jagadish, Usha; Sikka, Vinod K.

    2008-11-11

    A low-power shock sensing system includes at least one shock sensor physically coupled to a chemical storage tank to be monitored for impacts, and an RF transmitter which is in a low-power idle state in the absence of a triggering signal. The system includes interference circuitry including or activated by the shock sensor, wherein an output of the interface circuitry is coupled to an input of the RF transmitter. The interface circuitry triggers the RF transmitting with the triggering signal to transmit an alarm message to at least one remote location when the sensor senses a shock greater than a predetermined threshold. In one embodiment the shock sensor is a shock switch which provides an open and a closed state, the open state being a low power idle state.

  12. Remote shock sensing and notification system

    Energy Technology Data Exchange (ETDEWEB)

    Muralidharan, Govindarajan [Knoxville, TN; Britton, Charles L [Alcoa, TN; Pearce, James [Lenoir City, TN; Jagadish, Usha [Knoxville, TN; Sikka, Vinod K [Oak Ridge, TN

    2010-11-02

    A low-power shock sensing system includes at least one shock sensor physically coupled to a chemical storage tank to be monitored for impacts, and an RF transmitter which is in a low-power idle state in the absence of a triggering signal. The system includes interface circuitry including or activated by the shock sensor, wherein an output of the interface circuitry is coupled to an input of the RF transmitter. The interface circuitry triggers the RF transmitter with the triggering signal to transmit an alarm message to at least one remote location when the sensor senses a shock greater than a predetermined threshold. In one embodiment the shock sensor is a shock switch which provides an open and a closed state, the open state being a low power idle state.

  13. Flexible Thin Metal Film Thermal Sensing System

    Science.gov (United States)

    Thomsen, Donald Laurence (Inventor)

    2012-01-01

    A flexible thin metal film thermal sensing system is provided. A thermally-conductive film made from a thermally-insulating material is doped with thermally-conductive material. At least one layer of electrically-conductive metal is deposited directly onto a surface of the thermally-conductive film. One or more devices are coupled to the layer(s) to measure an electrical characteristic associated therewith as an indication of temperature.

  14. Fabrication of a Multi-Walled Nanotube (MWNT Ionic Liquid Electrode and Its Application for Sensing Phenolics in Red Wines

    Directory of Open Access Journals (Sweden)

    Kyo-Il Kim

    2009-08-01

    Full Text Available A multi-walled nanotube (MWNT ionic liquid was prepared by the immobilization of 1-butylimidazole bromide onto an epoxy group on a poly(glycidyl methacrylate-grafted MWNT, which was synthesized by radiation-induced graft polymerization of glycidyl methacrylate onto MWNT in an aqueous solution. Subsequently, a MWNT ionic liquid electrode was fabricated by hand-casting MWNT ionic liquid, tyrosinase, and chitosan solution as a binder on indium tin oxide (ITO glass. The sensing ranges of the MWNT ionic liquid electrode with immobilized tyrosinase was in the range of 0.01-0.08 mM in a phosphate buffer solution. The optimal conditions such as pH, temperature, and effects of different phenolic compounds were determined. The total phenolic compounds of three commercial red wines were also determined on the tyrosinase-immobilized biosensor.

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

    Science.gov (United States)

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

    2014-08-01

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

  16. A carbon nanotubes based ATP apta-sensing platform and its application in cellular assay.

    Science.gov (United States)

    Zhang, Libing; Wei, Hui; Li, Jing; Li, Tao; Li, Dan; Li, Yunhui; Wang, Erkang

    2010-04-15

    In this paper, a sensitive and selective fluorescent aptasensor for adenosine triphosphate (ATP) detection is constructed, based on the noncovalent assembly of dye-labeled ATP aptamer and single-walled carbon nanotubes (SWNTs). In the absence of ATP, the dye tethered to the ATP aptamer is close to SWNTs, which can effectively quench fluorescence of the dye. Upon adding ATP, the fluorophore keeps away from the quencher, since ATP specifically binds to the aptamer and competes with carbon nanotubes, resulting in an increase in the fluorescence intensity. This enables ATP to be detected down to 4.5nM. To the best of our knowledge, this is the most sensitive fluorescent ATP aptasensor. In addition, prominent fluorescence signals were obtained in cellular ATP assays, thus the aptasensor could be used to detect ATP in real samples.

  17. Carbon nanotube-based sensing devices for human Arginase-1 detection

    Directory of Open Access Journals (Sweden)

    S. Baldo

    2016-03-01

    Full Text Available A new carbon nanotube-based device for detection of Arginase 1 (ARG-1 was produced. Multi-walled carbon nanotubes (MWCNTs were deposited between electrodes by dielectrophoresis (DEP in an accurate and reproducible way. This deposition method has the advantages of low cost and room temperature conditions and therefore, can be used on different kinds of substrates (silicon, glass, plastics allowing for large scale production of chemical or biological sensors. Scanning electrical microscope (SEM and electrical characterization have been performed on the biosensors before and after protein exposure. The devices were tested in the present work for the detection of ARG-1. They show high sensitivity and reproducibility, and can be easily and suitably modified to detect other proteins.

  18. Exploring the electronic, vibrational, and chemical sensing properties of graphene, nanotubes, nanoparticles, and other nanomaterials

    OpenAIRE

    Sussman, Allen

    2013-01-01

    Some might view the "nano revolution" as one of the most important developments of our time, as nanomaterials have been and continue to be a seemingly endless source of new and exciting physics and have found application in almost every imaginable aspect of our lives. Carbon allotropes such as graphene, which is a single atomic layer of carbon atoms in a hexagonal lattice, carbon nanotubes (CNTs), which can be thought of as graphene sheets rolled up into cylinders, and graphene nanoribbons (...

  19. Single-Walled Carbon Nanotubes as Fluorescence Biosensors for Pathogen Recognition in Water Systems

    Directory of Open Access Journals (Sweden)

    Venkata K. K. Upadhyayula

    2008-01-01

    Full Text Available The possibility of using single-walled carbon nanotubes (SWCNTs aggregates as fluorescence sensors for pathogen recognition in drinking water treatment applications has been studied. Batch adsorption study is conducted to adsorb large concentrations of Staphylococcus aureus aureus SH 1000 and Escherichia coli pKV-11 on single-walled carbon nanotubes. Subsequently the immobilized bacteria are detected with confocal microscopy by coating the nanotubes with fluorescence emitting antibodies. The Freundlich adsorption equilibrium constant (k for S.aureus and E.coli determined from batch adsorption study was found to be 9×108 and 2×108 ml/g, respectively. The visualization of bacterial cells adsorbed on fluorescently modified carbon nanotubes is also clearly seen. The results indicate that hydrophobic single-walled carbon nanotubes have excellent bacterial adsorption capacity and fluorescent detection capability. This is an important advancement in designing fluorescence biosensors for pathogen recognition in water systems.

  20. Carbon nanotubes as nanodelivery systems an insight through molecular dynamics simulations

    CERN Document Server

    Lim, Melvin Choon Giap

    2013-01-01

    This book showcases the application of carbon nanotubes as nanodelivery systems for copper atoms, using molecular dynamics simulations as a means of investigation. The nanodelivery system of the carbon nanotube presents the possible usage of the carbon structure in many areas in the future. This book is comprehensive and informative, and serves as a guide for any reader who wishes to perform a molecular dynamics simulation of his own and to conduct an analytical study of a molecular system.

  1. Inorganic nanotube nanofluidics

    Science.gov (United States)

    Fan, Rong

    , a positive gate voltage depletes cations (majority) while a negative gate further enhances cation concentration. The resulting device is essentially a p-type ionic transistor. The inherent carrier concentration within nanotubes is determined by surface potentials and charge densities. Therefore, surface modification, which alters surface charges, can change the inherent carrier density and even switch channel polarity. We functionalize the hydroxyl group terminated silica surfaces with aminosilane chemistry, thus modifying the surface charge density and creating ambipolar and n-type nanofluidic transistors. We further employed the Poisson-Boltzmann model to systematically analyze these results. Transient responses upon switching on gate voltages lead us to propose a first kinetic model to explain the field effect modulation in nanofluidic systems. This single nanotube-based nanofluidic device, which has dimensions comparable to the size of biomolecules, represents a new-platform for single molecule detection. lambda-DNA translocations through single nanotubes were stochastically sensed by ionic current changes. The results turned out that both charge effect and geometrical effect play key roles in, single molecule sensing. These high aspect ratio nanotubes provide a novel approach to investigate the conformational evolution from the fine structure of ionic current curves, which is mechanistically different from that for narrow nanopores. The development of microtrench-based fabrication process enables the custom-designed and multiplexed nanotube nanofluidic systems. The anionic dye diffusion was regulated by ionic strength, in agreement with unipolar transport mechanism. A well-aligned mesoporous nanochannel thin film was exploited for sub-10nm nanofluidics. Nanofluidics is attracting increasing attention in bioanalytical technology and biophysics field. MOSolFETs represent the key units for building up large-scale nanofluidic processors and logic circuits. This

  2. Carbon Nanotube Based Nano-Electro-Mechanical Systems (NEMS)

    Science.gov (United States)

    Han, Jie; Dai, Hongjie; Saini, Subhash

    1998-01-01

    Carbon nanotubes (CNT) enable nanoelectromechanical systems (NEMS) because of their inherent nanostructure, intrinsic electric conductivity and mechanical resilience. The collaborative work between Stanford (experiment) and NASA Ames (theory and simulation) has made progress in two types of CNT based NEMS for nanoelectronics and sensor applications. The CNT tipped scanning probe microscopy (SPM) is a NEMS in which CNT tips are used for nanoscale probing, imaging and manipulating. It showed great improvement in probing surfaces and biological systems over conventional tips. We have recently applied it to write (lithography) and read (image) uniform SiO2 lines on large Si surface area at speed up to 0.5 mm per s. Preliminary work using approximately 10 nm multiwall nanotube tips produced approximately 10 nm structures and showed that the CNT tips didn't wear down when crashed as conventional tips often do. This presents a solution to the long standing tip-wear problem in SPM nanolithography. We have also explored potential of CNT tips in imaging DNA in water. Preliminary experiment using 10 nm CNT tips reached 5 nm resolution. The 1 nm nanolithography and 1 nm DNA imaging can be expected by using approximately 1 nm CNT tips. In contrast to CNT tipped SPM, we also fabricated CNT devices on silicon wafer in which CNTs connect patterned metallic lines on SiO2/Si by a simple chemical vapor deposition process. Using conventional lithography for silicon wafer, we have been able to obtain CNT based transistors and sensors. Investigations of the CNT NEMS as physical, biological and chemical sensors are in progress and will be discussed.

  3. Role of carbon nanotubes in electroanalytical chemistry: a review.

    Science.gov (United States)

    Agüí, Lourdes; Yáñez-Sedeño, Paloma; Pingarrón, José M

    2008-08-01

    This review covers recent advances in the development of new designs of electrochemical sensors and biosensors that make use of electrode surfaces modification with carbon nanotubes. Applications based on carbon nanotubes-driven electrocatalytic effects, and the construction and analytical usefulness of new hybrid materials with polymers or other nanomaterials will be treated. Moreover, electrochemical detection using carbon nanotubes-modified electrodes as detecting systems in separation techniques such as high performance liquid chromatography (HPLC) or capillary electrophoresis (CE) will be also considered. Finally, the preparation of electrochemical biosensors, including enzyme electrodes, immunosensors and DNA biosensors, in which carbon nanotubes play a significant role in their sensing performance will be separately considered.

  4. Transport Phenomena in Nanowires, Nanotubes, and Other Low-Dimensional Systems

    KAUST Repository

    Montes, Enrique

    2017-01-01

    ~ 200%, which halves for an applied voltage of about 0.35 V and persist up to 1 V. In order to account for shallow impurities coming from bulk Si, the nanowire is doped with either P or B atoms (n or p type). Doping in general decreases the magnetoresistance as soon as the conductance is no longer dominated by tunneling. On the other hand, we study the electron transport properties of Si nanotubes connected to Au electrodes. The general properties turn out to be largely independent of the nanotube chirality, diameter, and length. However, the tunneling conductance of Si nanotubes is found to be significantly larger than in Si nanowires, while having a comparable band gap. For this reason we simulate a Si nanotube field effect transistor by applying an uniform potential gate. Our results demonstrate very high values of the transconductance, outperforming the best commercial Si field effect transistors, combined with low values of the subthreshold swing. Phosphorene (monolayer black P) is the only elemental two-dimensional material besides graphene that can be mechanically exfoliated and also can support electronics. Specific dislocations of the atoms in the phosphorene lattice generate another stable two-dimensional allotrope with buckled honeycomb lattice, blue P. We demonstrate structural stability of monolayer zigzag and armchair blue P nanotubes by means of molecular dynamics simulations. The vibrational spectrum and electronic band structure are determined and analyzed as functions of the tube diameter and axial strain. The nanotubes are found to be semiconductors with a sensitive indirect band gap that allows flexible tuning. We study the adsorption of CO, CO2, NH3, NO, and NO2 molecules on blue P nanotubes. They are found to surpass the gas sensing performance of other nanoscale materials. Investigations of the gas adsorption and induced charge transfer indicate that blue P nanotubes are highly sensitive to N-based molecules, in particular NO2, due to covalent

  5. Self-Assemblies of Single-Walled Carbon Nanotubes through Tunable Tethering of Pyrenes by Dextrin for Rapidly Chiral Sensing

    Directory of Open Access Journals (Sweden)

    Wei-Li Wei

    2011-01-01

    Full Text Available Pyrene-modified dextrin (Py-Dex was synthesized via the Schiff base reaction between reducing end of dextrins and 1-aminopyrene, and then self-assemblies of single-walled carbon nanotubes (SWNTs were fabricated through the tunable tethering of pyrene to SWNTs by dextrin chains. The Py-Dex-SWNTs assemblies were found to be significantly water-soluble because of the synergistic effect of dextrin chains and pyrene moieties. Py-Dex and Py-Dex-SWNTs were adequately characterized by NMR, UV-vis, fluorescence spectroscopy, Raman spectroscopy, matrix-assisted laser desorption/ionization-time of flight mass spectroscopy, and transmission electron microscopy. The tethering effect of dextrin toward pyrene moieties was clearly revealed and was found to be tunable by adjusting the length of dextrin chains. The fluorescence of pyrene moieties was sufficiently quenched by SWNTs with the support of dextrin chains. Furthermore, the Py-Dex-SWNTs assemblies were used for chiral selective sensing by introducing cyclodextrins as chiral binding sites. The rapid chiral sensing was successfully tested for different enantiomers.

  6. Mechanical resonators based on nanotubes and graphene

    Science.gov (United States)

    Bachtold, Adrian

    2013-03-01

    Carbon nanotubes and graphene offer unique scientific and technological opportunities as nanoelectromechanical systems (NEMS). Namely, they have allowed the fabrication of mechanical resonators that can be operable at ultra-high frequencies and that can be employed as ultra-sensitive sensors of mass and charge. In addition, nanotubes and graphene have exceptional electron transport properties, including ballistic conduction over long distances. Coupling the mechanical motion to electron transport in these remarkable materials is thus highly appealing. Here, I will review some of our recent results on nanotube and graphene NEMSs, including the control of the mechanical oscillation using Coulomb blockade and mass sensing at the proton mass level.

  7. Rapid deployable global sensing hazard alert system

    Science.gov (United States)

    Cordaro, Joseph V; Tibrea, Steven L; Shull, Davis J; Coleman, Jerry T; Shuler, James M

    2015-04-28

    A rapid deployable global sensing hazard alert system and associated methods of operation are provided. An exemplary system includes a central command, a wireless backhaul network, and a remote monitoring unit. The remote monitoring unit can include a positioning system configured to determine a position of the remote monitoring unit based on one or more signals received from one or more satellites located in Low Earth Orbit. The wireless backhaul network can provide bidirectional communication capability independent of cellular telecommunication networks and the Internet. An exemplary method includes instructing at least one of a plurality of remote monitoring units to provide an alert based at least in part on a location of a hazard and a plurality of positions respectively associated with the plurality of remote monitoring units.

  8. A microelectromechanically controlled cavity optomechanical sensing system

    CERN Document Server

    Miao, Houxun; Aksyuk, Vladimir

    2012-01-01

    Microelectromechanical systems (MEMS) have been applied to many measurement problems in physics, chemistry, biology and medicine. In parallel, cavity optomechanical systems have achieved quantum-limited displacement sensitivity and ground state cooling of nanoscale objects. By integrating a novel cavity optomechanical structure into an actuated MEMS sensing platform, we demonstrate a system with high quality-factor interferometric readout, electrical tuning of the optomechanical coupling by two orders of magnitude, and a mechanical transfer function adjustable via feedback. The platform separates optical and mechanical components, allowing flexible customization for specific scientific and commercial applications. We achieve displacement sensitivity of 4.6 fm/Hz^1/2 and force sensitivity of 53 aN/Hz^1/2 with only 250 nW optical power launched into the sensor. Cold-damping feedback is used to reduce the thermal mechanical vibration of the sensor by 3 orders of magnitude and to broaden the sensor bandwidth by a...

  9. Rapid deployable global sensing hazard alert system

    Energy Technology Data Exchange (ETDEWEB)

    Cordaro, Joseph V; Tibrea, Steven L; Shull, Davis J; Coleman, Jerry T; Shuler, James M

    2015-04-28

    A rapid deployable global sensing hazard alert system and associated methods of operation are provided. An exemplary system includes a central command, a wireless backhaul network, and a remote monitoring unit. The remote monitoring unit can include a positioning system configured to determine a position of the remote monitoring unit based on one or more signals received from one or more satellites located in Low Earth Orbit. The wireless backhaul network can provide bidirectional communication capability independent of cellular telecommunication networks and the Internet. An exemplary method includes instructing at least one of a plurality of remote monitoring units to provide an alert based at least in part on a location of a hazard and a plurality of positions respectively associated with the plurality of remote monitoring units.

  10. Gas sensing properties of multiwall carbon nanotubes decorated with Rh nanoparticles

    CERN Document Server

    Leghrib, Radouane; Demoisson, Frédéric; Claessens, Nicolas; Reniers, François; Llobet, Eduard

    2016-01-01

    In the present work, multiwalled carbon nanotubes were decorated with rhodium nanoparticles using a colloidal solution in the post-discharge of an RF atmospheric plasma of argon (Ar) or argon/oxygen (Ar:O$_2$). The properties of these hybrid materials towards the room temperature detection of NO$_2$, C$_2$H$_4$, CO, C$_6$H$_6$ and moisture were investigated and discussed in view of compositional and morphological studies. It was found that the presence of oxygen in the plasma treatment is essential to significantly enhance the gas response of Rh-decorated multiwalled carbon nanotubes and to avoid response saturation even at low gas/vapor concentrations. These desirable effects are attributed to the presence of oxygen during the CNT plasma treatment since oxygenated vacancies act both as active adsorption sites for gases and as anchoring sites for Rh nanoparticles (the presence of Rh nanoclusters is nearly doubled in Ar-O$_2$ treated samples as compared to Ar treated samples). The oxygen treatment also makes e...

  11. Systems and Methods for Fabricating Carbon Nanotube-Based Vacuum Electronic Devices

    Science.gov (United States)

    Manohara, Harish (Inventor); Toda, Risaku (Inventor); Del Castillo, Linda Y. (Inventor); Murthy, Rakesh (Inventor)

    2015-01-01

    Systems and methods in accordance with embodiments of the invention proficiently produce carbon nanotube-based vacuum electronic devices. In one embodiment a method of fabricating a carbon nanotube-based vacuum electronic device includes: growing carbon nanotubes onto a substrate to form a cathode; assembling a stack that includes the cathode, an anode, and a first layer that includes an alignment slot; disposing a microsphere partially into the alignment slot during the assembling of the stack such that the microsphere protrudes from the alignment slot and can thereby separate the first layer from an adjacent layer; and encasing the stack in a vacuum sealed container.

  12. Micro-system inertial sensing technology overview.

    Energy Technology Data Exchange (ETDEWEB)

    Allen, James Joe

    2009-02-01

    The purpose of this report is to provide an overview of Micro-System technology as it applies to inertial sensing. Transduction methods are reviewed with capacitance and piezoresistive being the most often used in COTS Micro-electro-mechanical system (MEMS) inertial sensors. Optical transduction is the most recent transduction method having significant impact on improving sensor resolution. A few other methods are motioned which are in a R&D status to hopefully allow MEMS inertial sensors to become viable as a navigation grade sensor. The accelerometer, gyroscope and gravity gradiometer are the type of inertial sensors which are reviewed in this report. Their method of operation and a sampling of COTS sensors and grade are reviewed as well.

  13. Lipid nanotube or nanowire sensor

    Science.gov (United States)

    Noy, Aleksandr; Bakajin, Olgica; Letant, Sonia; Stadermann, Michael; Artyukhin, Alexander B.

    2009-06-09

    A sensor apparatus comprising a nanotube or nanowire, a lipid bilayer around the nanotube or nanowire, and a sensing element connected to the lipid bilayer. Also a biosensor apparatus comprising a gate electrode; a source electrode; a drain electrode; a nanotube or nanowire operatively connected to the gate electrode, the source electrode, and the drain electrode; a lipid bilayer around the nanotube or nanowire, and a sensing element connected to the lipid bilayer.

  14. Phone-sized whispering-gallery microresonator sensing system

    CERN Document Server

    Xu, Xiangyi; Zhao, Guangming; Yang, Lan

    2016-01-01

    We develop a compact whispering-gallery-mode (WGM) sensing system by integrating multiple components, including a tunable laser, a temperature controller, a function generator, an oscilloscope, a photodiode detector, and a testing computer, into a phone-sized embedded system. We demonstrate a thermal sensing experiment by using this portable system. Such a system successfully eliminates bulky measurement equipment required for characterizing optical resonators and will open up new avenues for practical sensing applications by using ultra-high Q WGM resonators.

  15. Phone-sized whispering-gallery microresonator sensing system

    Science.gov (United States)

    Xu, Xiangyi; Jiang, Xuefeng; Zhao, Guangming; Yang, Lan

    2016-11-01

    We develop a compact whispering-gallery-mode (WGM) sensing system by integrating multiple components, including a tunable laser, a temperature controller, a function generator, an oscilloscope, a photodiode detector, and a testing computer, into a phone-sized embedded system. We demonstrate a thermal sensing experiment by using this portable system. Such a system successfully eliminates bulky measurement equipment required for characterizing optical resonators and will open up new avenues for practical sensing applications by using ultra-high Q WGM resonators.

  16. Acriflavine immobilized onto polyethyleneimine-wrapped carbon nanotubes/gold nanoparticles as an eletrochemical sensing platform

    Indian Academy of Sciences (India)

    Azadeh Azadbakht; Amirreza Abbasi

    2016-02-01

    Multi-walled carbon nanotubes wrapped by polyethyleneimine (PEI) and functionalized with a carboxylic acid group (CNT-COOH) were deposited with gold nanoparticles (AuNPs) which has been utilized as a platform to immobilize poly(acriflavine)(PAF) and used as modified electrode (AuNPs/PEI/CNTCOOH/PAF). Electrocatalytic reduction of hydrogen peroxide(H2O2) on the surface of the modified electrode was investigated by cyclic voltammetry and electrochemical impedance spectroscopy (EIS) methods. The cyclic voltammetric results indicated the ability of modified Au electrode to catalyze the reduction of H2O2. AuNPs/PEI/CNT-COOH nanocomposite combined the advantages of PEI, well dispersed CNT-COOH and in situ formed AuNPs, endowed with high stability to the enzyme-free sensor.

  17. The Fundamental Framework of Remote Sensing Validation System

    Science.gov (United States)

    Jiang, X.-G.; Xi, X.-H.; Wu, M.-J.; Li, Z.-L.

    2009-04-01

    Remote sensing is a very complicated course. It is influenced by many factors, such as speciality of remote sensing sensor, radiant transmission characteristic of atmosphere, work environment of remote sensing platform, data transmission, data reception, data processing, and property of observed object etc. Whether the received data is consistent with the design specifications? Can the data meet the demands of remote sensing applications? How about the accuracy of the data products, retrieval products and application products of remote sensing? It is essential to carry out the validation to assess the data quality and application potential. Validation is effective approach to valuate remote sensing products. It is the significant link between remote sensing data and information. Research on remote sensing validation is very important for sensor development, data quality analysis and control. This paper focuses on the study of remote sensing validation and validation system. Different from the previous work done by other researchers, we study the validation from the viewpoint of systematic engineering considering that validation is involved with many aspects as talked about. Validation is not just a single and simple course. It is complicated system. Validation system is the important part of whole earth observation system. First of all, in this paper the category of remote sensing validation is defined. Remote sensing validation includes not only the data products validation, but also the retrieval products validation and application products validation. Second, the new concept, remote sensing validation system, is proposed. Then, the general framework, software structure and functions of validation system are studied and put forward. The validation system is composed of validation field module, data acquirement module, data processing module, data storage and management module, data scaling module, and remote sensing products validation module. And finally the

  18. Ultrasensitive Label-Free Sensing of IL-6 Based on PASE Functionalized Carbon Nanotube Micro-Arrays with RNA-Aptamers as Molecular Recognition Elements.

    Science.gov (United States)

    Khosravi, Farhad; Loeian, Seyed Masoud; Panchapakesan, Balaji

    2017-04-17

    This study demonstrates the rapid and label-free detection of Interleukin-6 (IL-6) using carbon nanotube micro-arrays with aptamer as the molecular recognition element. Single wall carbon nanotubes micro-arrays biosensors were manufactured using photo-lithography, metal deposition, and etching techniques. Nanotube biosensors were functionalized with 1-Pyrenebutanoic Acid Succinimidyl Ester (PASE) conjugated IL-6 aptamers. Real time response of the sensor conductance was monitored with increasing concentration of IL-6 (1 pg/mL to 10 ng/mL), exposure to the sensing surface in buffer solution, and clinically relevant spiked blood samples. Non-specific Bovine Serum Albumin (BSA), PBS samples, and anti-IgG functionalized devices gave similar signatures in the real time conductance versus time experiments with no significant change in sensor signal. Exposure of the aptamer functionalized nanotube surface to IL-6 decreased the conductance with increasing concentration of IL-6. Experiments based on field effect transistor arrays suggested shift in drain current versus gate voltage for 1 pg and 1 ng of IL-6 exposure. Non-specific BSA did not produce any appreciable shift in the Ids versus Vg suggesting specific interactions of IL-6 on PASE conjugated aptamer surface gave rise to the change in electrical signal. Both Z axis and phase image in an Atomic Force Microscope (AFM) suggested unambiguous molecular interaction of the IL-6 on the nanotube-aptamer surface at 1 pg/mL concentration. The concentration of 1 pg falls below the diagnostic gray zone for cancer (2.3 pg-4 ng/mL), which is an indicator of early stage cancer. Thus, nanotube micro-arrays could potentially be developed for creating multiplexed assays involving cancer biomarker proteins and possibly circulating tumor cells all in a single assay using PASE functionalization protocol.

  19. Carbon nanotube nanoelectromechanical systems as magnetometers for single-molecule magnets.

    Science.gov (United States)

    Ganzhorn, Marc; Klyatskaya, Svetlana; Ruben, Mario; Wernsdorfer, Wolfgang

    2013-07-23

    Due to outstanding mechanical and electronic properties, carbon nanotube nanoelectromechanical systems (NEMS) were recently proposed as ultrasensitive magnetometers for single-molecule magnets (SMM). In this article, we describe a noninvasive grafting of a SMM on a carbon nanotube NEMS, which conserves both the mechanical properties of the carbon nanotube NEMS and the magnetic properties of the SMM. We will demonstrate that the nonlinearity of a carbon nanotube's mechanical motion can be used to probe the reversal of a molecular spin, associated with a bis(phthalocyaninato)terbium(III) single-molecule magnet, providing an experimental evidence for the detection of a single spin by a mechanical degree of freedom on a molecular level.

  20. Carbon nanotube nanoelectrode arrays

    Science.gov (United States)

    Ren, Zhifeng; Lin, Yuehe; Yantasee, Wassana; Liu, Guodong; Lu, Fang; Tu, Yi

    2008-11-18

    The present invention relates to microelectode arrays (MEAs), and more particularly to carbon nanotube nanoelectrode arrays (CNT-NEAs) for chemical and biological sensing, and methods of use. A nanoelectrode array includes a carbon nanotube material comprising an array of substantially linear carbon nanotubes each having a proximal end and a distal end, the proximal end of the carbon nanotubes are attached to a catalyst substrate material so as to form the array with a pre-determined site density, wherein the carbon nanotubes are aligned with respect to one another within the array; an electrically insulating layer on the surface of the carbon nanotube material, whereby the distal end of the carbon nanotubes extend beyond the electrically insulating layer; a second adhesive electrically insulating layer on the surface of the electrically insulating layer, whereby the distal end of the carbon nanotubes extend beyond the second adhesive electrically insulating layer; and a metal wire attached to the catalyst substrate material.

  1. Enhancement of dopamine sensing by layer-by-layer assembly of PVI-dmeOs and Nafion on carbon nanotubes

    Science.gov (United States)

    Cui, Hui-Fang; Cui, Yu-Han; Sun, Yu-Long; Zhang, Kuan; Zhang, Wei-De

    2010-05-01

    In this study, carbon nanotubes (CNTs) were modified to further improve their performance in electrochemical sensing of dopamine (DA) levels. After a redox polymer, poly(vinylimidazole) complexed with Os(4, 4'-dimethyl- 2, 2-bipyridine)2Cl (termed PVI-dmeOs) was electrodeposited on multi-wall CNTs (MWCNTs), Nafion and PVI-dmeOs films were successfully layer-by-layer (LBL) assembled on the hydrophilic surface of the as-prepared PVI-dmeOs/CNTs nanocomposites through electrostatic interactions. The LBL assembly was proved by scanning electron microscopy (SEM), electrochemistry and UV-vis spectroscopy measurements. LBL assembly of Nafion/PVI-dmeOs films on CNTs significantly enhanced their linear sweep voltammetry (LSV) response sensitivity to DA, with a maximum enhancement for three Nafion/PVI-dmeOs film-modified MWCNTs. The LSV peak current density of (Nafion/PV I-dmeOs)3/CNT electrodes in response to 10 and 50 µM DA solutions was about 7.3 and 3.9 times those for bare CNTs. At the (Nafion/PV I-dmeOs)3/CNT electrodes, the limit of detection (LOD) (signal-to-noise ratio: 3) was 0.05 µM DA, the linear range was 0.1-10 µM DA (with a linear regression coefficient of 0.97) and the DA-sensing sensitivity was 8.15 µA cm - 2 µM - 1. The newly fabricated (Nafion/PV I-dmeOs)3/CNT electrodes may be developed as an ideal biosensor for direct and in situ measurement of DA levels.

  2. Enhancement of dopamine sensing by layer-by-layer assembly of PVI-dmeOs and Nafion on carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Cui Huifang; Cui Yuhan; Sun Yulong; Zhang Kuan [Department of Bioengineering, Zhengzhou University, 100 Science Avenue, Zhengzhou 450001 (China); Zhang Weide, E-mail: hfcui@zzu.edu.cn [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China)

    2010-05-28

    In this study, carbon nanotubes (CNTs) were modified to further improve their performance in electrochemical sensing of dopamine (DA) levels. After a redox polymer, poly(vinylimidazole) complexed with Os(4, 4'-dimethyl- 2, 2-bipyridine){sub 2}Cl (termed PVI-dmeOs) was electrodeposited on multi-wall CNTs (MWCNTs), Nafion and PVI-dmeOs films were successfully layer-by-layer (LBL) assembled on the hydrophilic surface of the as-prepared PVI-dmeOs/CNTs nanocomposites through electrostatic interactions. The LBL assembly was proved by scanning electron microscopy (SEM), electrochemistry and UV-vis spectroscopy measurements. LBL assembly of Nafion/PVI-dmeOs films on CNTs significantly enhanced their linear sweep voltammetry (LSV) response sensitivity to DA, with a maximum enhancement for three Nafion/PVI-dmeOs film-modified MWCNTs. The LSV peak current density of (Nafion/PV I-dmeOs){sub 3}/CNT electrodes in response to 10 and 50 {mu}M DA solutions was about 7.3 and 3.9 times those for bare CNTs. At the (Nafion/PV I-dmeOs){sub 3}/CNT electrodes, the limit of detection (LOD) (signal-to-noise ratio: 3) was 0.05 {mu}M DA, the linear range was 0.1-10 {mu}M DA (with a linear regression coefficient of 0.97) and the DA-sensing sensitivity was 8.15 {mu}A cm{sup -2} {mu}M{sup -1}. The newly fabricated (Nafion/PV I-dmeOs){sub 3}/CNT electrodes may be developed as an ideal biosensor for direct and in situ measurement of DA levels.

  3. One-dimensional carbon nanotube/SnO2/noble metal nanoparticle hybrid nanostructure: synthesis, characterization, and electrochemical sensing.

    Science.gov (United States)

    Fang, Youxing; Guo, Shaojun; Zhu, Chengzhou; Dong, Shaojun; Wang, Erkang

    2010-08-02

    Herein we report a facile and efficient method for self-assembling noble-metal nanoparticles (NPs) to the surface of SnO(2)-coated carbon nanotubes (CNT@SnO(2)) to construct CNT@SnO(2)/noble metal NP hybrids. By using SnCl(4) as the precursor of the SnO(2) shell on the surface of CNTs, the hydrolysis speed of SnCl(4) was slowed down in ethanol containing a trace amount of urea and water. The coaxial nanostructure of CNT@SnO(2) was confirmed by using X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). It was found that the coating layer of SnO(2) was homogeneous with the mean thickness of 8 nm. The CNT@SnO(2)/noble-metal NP hybrids were obtained by mixing noble-metal NPs with as-prepared CNT@SnO(2) coaxial nanocables by means of a self-assembly strategy. With the amino group terminated, the CNT@SnO(2) coaxial nanocable can readily adsorb the as-prepared noble-metal NPs (Au, Ag, Au-Pt, and Au-Pd NPs). The presence of an amino group at the surface of SnO(2) was proved by use of X-ray photoelectron spectroscopy (XPS). In addition, H(2)O(2) sensing by amperometric methods could serve as detection models for investigating the electrocatalytic ability of as-prepared hybrid materials. It was found that wide linear ranges and low detection limits were obtained by using the enzyme-free CNT@SnO(2)@Au-Pt modified electrode, which indicated the potential utilizations of the hybrid based on CNT@SnO(2) for electrochemical sensing.

  4. Carbon nanotubes-ionic liquid nanocomposites sensing platform for NADH oxidation and oxygen, glucose detection in blood.

    Science.gov (United States)

    Bai, Lu; Wen, Dan; Yin, Jianyuan; Deng, Liu; Zhu, Chengzhou; Dong, Shaojun

    2012-03-15

    An excellent electrochemical sensing platform has been designed by combining the huge specific surface area of carbon nanotubes (CNTs) and the remarkable conductivity of ionic liquid (IL). IL can easily untangle CNTs bundles and disperse CNTs by itself under grinding condition due to the π-π interaction between CNTs and IL. The resulting nanocomposites showed an augmentation on the voltammetric and amperometric behaviors of electrocatalytic activity toward O(2) and NADH. Therefore, such an efficient platform was developed to fabricate mediator-free oxygen sensor and glucose biosensor based on glucose dehydrogenase (GDH). O(2) could be determined in the range of zero to one hundred percent of O(2) content with the detection limit of 126 μg L(-1) (S/N=3). The glucose biosensor which was constructed by entrapping GDH into chitosan on the nanocomposites modified glassy carbon electrode surface, exhibited good electrocatalytic oxidation toward glucose with a detection limit of 9 μM in the linear range of 0.02-1mM. We also applied the as-prepared sensors to detect oxygen and glucose in real blood samples and acquired satisfied results. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Resistive sensing of gaseous nitrogen dioxide using a dispersion of single-walled carbon nanotubes in an ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Prabhash [Solidstate Electronics Research Laboratory (SERL), Faculty of Engineering and Technology, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025 (India); Department of Nanoengineering, Samara State Aerospace University, 443086 Samara (Russian Federation); Pavelyev, V.S. [Department of Nanoengineering, Samara State Aerospace University, 443086 Samara (Russian Federation); Patel, Rajan [Center for Interdisciplinary Research in Basic Sciences (CIRBSc), Jamia Millia Islamia, Jamia Nagar, New Delhi 110025 (India); Islam, S.S., E-mail: sislam@jmi.ac.in [Solidstate Electronics Research Laboratory (SERL), Faculty of Engineering and Technology, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025 (India)

    2016-06-15

    Graphical abstract: Ionic liquid ([C6-mim]PF6) used as dispersant agent for SWCNTs: An investigations were carried out to find the structural quality and surface modification for sensor application. - Highlights: • An effective technique based on Ionic liquids (IL) and their use as a dispersant. • Electron microscopy and spectroscopy for structure characterization. • Covalent linkage of ILs with SWNTs and dispersion of SWCNTs. • The IL-wrapped sensing film, capable for detecting trace levels of gas. - Abstract: Single-walled carbon nanotubes (SWCNTs) were dispersed in an imidazolium-based ionic liquid (IL) and investigated in terms of structural quality, surface functionalization and inter-CNT force. Analysis by field emission electron microscopy and transmission electron microscopy shows the IL layer to coat the SWNTs, and FTIR and Raman spectroscopy confirm strong binding of the ILs to the SWNTs. Two kinds of resistive sensors were fabricated, one by drop casting of IL-wrapped SWCNTs, the other by conventional dispersion of SWCNTs. Good response and recovery to NO{sub 2} is achieved with the IL-wrapped SWCNTs material upon UV-light exposure, which is needed because decrease the desorption energy barrier to increase the gas molecule desorption. NO{sub 2} can be detected in the 1–20 ppm concentration range. The sensor is not interfered by humidity due to the hydrophobic tail of PF6 (ionic liquid) that makes our sensor highly resistant to moisture.

  6. Characterization of the spatial elastoresistivity of inkjet-printed carbon nanotube thin films for strain-state sensing

    Science.gov (United States)

    Gruener, Patrick; Zhao, Yingjun; Schagerl, Martin

    2017-04-01

    Carbon nanotube (CNT)-embedded polymer solution can be inkjet-printed into a thin sheet consisting uniform morphology and consistent electrical properties. When subjected to a loading scheme, the thin film's inherent electrical property changes in tandem with the deformation. This unique property makes CNT thin films the appropriate candidate for strain sensing applications. Recent studies on characterizing the gage factor of CNT-embedded thin films are limited to learning the materials resistance change along the loading direction only. However, research interests on strain measurement of a structure have shifted from point-based interrogation to spatial strain-state monitoring. In this study an attempt to characterize its anisotropic resistivity was carried out. The resistivity-strain constitutional relation of an inkjet-printed CNT thin film is established based on theories for semi-conductive materials. The 2D elastoresistivity properties were characterized via the Montgomery method. It is observed that the change in resistivity in both directions are exhibiting linear trend to their strains in the same direction, but the thin film is more sensitive toward compressive strains. The final result of this study has inspired future research on fully characterizing the thin film's elastoresistivity under different loading situations, and the way to characterize shear elastoresistivity shall also be reconsidered.

  7. A tunable carbon nanotube electromechanical oscillator

    Science.gov (United States)

    Sazonova, Vera; Yaish, Yuval; Üstünel, Hande; Roundy, David; Arias, Tomás A.; McEuen, Paul L.

    2004-09-01

    Nanoelectromechanical systems (NEMS) hold promise for a number of scientific and technological applications. In particular, NEMS oscillators have been proposed for use in ultrasensitive mass detection, radio-frequency signal processing, and as a model system for exploring quantum phenomena in macroscopic systems. Perhaps the ultimate material for these applications is a carbon nanotube. They are the stiffest material known, have low density, ultrasmall cross-sections and can be defect-free. Equally important, a nanotube can act as a transistor and thus may be able to sense its own motion. In spite of this great promise, a room-temperature, self-detecting nanotube oscillator has not been realized, although some progress has been made. Here we report the electrical actuation and detection of the guitar-string-like oscillation modes of doubly clamped nanotube oscillators. We show that the resonance frequency can be widely tuned and that the devices can be used to transduce very small forces.

  8. Hydrogen sensing performance of WO3 thin film by using multi - wall carbon nanotubes

    Directory of Open Access Journals (Sweden)

    R. Ghasempour

    2014-04-01

    Full Text Available The WO3/MWNTs hybrid gas sensitive films were prepared by spin-coating on alumina substrate. The structure, morphology and chemical composition of the functionalized MWNTs and WO3/MWNTs hybrid films were studied by SEM, TEM, XRD, Raman, DLS and XPS methods. The MWCNT were initially functionalized (f-MWNTs. Dispersion and surface reactivity of MWNTs was improved because of oxygenate groups on MWNTs surface. Results showed WO3 nanoparticles were nucleated on oxygenated group on surface of f-MWNTs in hybrid suspension. After coating and annealing the films at 350 , the response of hybrid WO3/MWNTs films was measured. In addition, adding a little amount of MWNTs (the ratio of MWNTs/W less than 5/1000 wt% increased the hydrogen sensitivity so that the hybrid films showed an increase of 50 times compared to pure tungsten oxide layer in response to the 10000 ppm hydrogen concentration. Considering the results, the identification of these structures appear tobe 10 ppm hydrogen gas. With the addition of carbon nanotubes, the working temperature of pure tungsten oxide layers (400 reduced to 200 in hybrid layer. The gas sensitivity is suggested to have risendue to mainly the increase in the surface area as well as development of two types of depletion layers, one at the WO3/ MWNTs hetero junction and the other at WO3 grain boundaries.

  9. Optimized network of multi-walled carbon nanotubes for chemical sensing

    Science.gov (United States)

    Gohier, A.; Chancolon, J.; Chenevier, P.; Porterat, D.; Mayne-L'Hermite, M.; Reynaud, C.

    2011-03-01

    This work reports the design of a resistive gas sensor based on 2D mats of multi-walled carbon nanotubes (MWCNTs) grown by aerosol-assisted chemical vapour deposition. The sensor sensitivity was optimized using chlorine as analyte by tuning both CNT network morphology and CNT electronic properties. Optimized devices, operating at room temperature, have been calibrated over a large range of concentration and are shown to be sensitive down to 27 ppb of chlorine. The as-grown MWCNT response is compared with responses of 2000 °C annealed CNTs, as well as of nitrogen-doped CNTs and CNTs functionalized with polyethyleneimine (PEI). Under chlorine exposure, the resistance decrease of as-grown and annealed CNTs is attributed to charge transfer from chlorine to CNTs and demonstrates their p-type semiconductor behaviour. XPS analysis of CNTs exposed to chlorine shows the presence of chloride species that confirms electron charge transfer from chlorine to CNTs. By contrast, the resistance of nitrogen-doped and PEI functionalized CNTs exposed to chlorine increases, in agreement with their n-type semiconductor nature. The best response is obtained using annealed CNTs and is attributed to their higher degree of crystallinity.

  10. Gas Sensitivity and Sensing Mechanism Studies on Au-Doped TiO2 Nanotube Arrays for Detecting SF6 Decomposed Components

    Directory of Open Access Journals (Sweden)

    Xiaoxing Zhang

    2014-10-01

    Full Text Available The analysis to SF6 decomposed component gases is an efficient diagnostic approach to detect the partial discharge in gas-insulated switchgear (GIS for the purpose of accessing the operating state of power equipment. This paper applied the Au-doped TiO2 nanotube array sensor (Au-TiO2 NTAs to detect SF6 decomposed components. The electrochemical constant potential method was adopted in the Au-TiO2 NTAs’ fabrication, and a series of experiments were conducted to test the characteristic SF6 decomposed gases for a thorough investigation of sensing performances. The sensing characteristic curves of intrinsic and Au-doped TiO2 NTAs were compared to study the mechanism of the gas sensing response. The results indicated that the doped Au could change the TiO2 nanotube arrays’ performances of gas sensing selectivity in SF6 decomposed components, as well as reducing the working temperature of TiO2 NTAs.

  11. Single-walled and multi-walled carbon nanotubes based drug delivery system: Cancer therapy: A review

    Directory of Open Access Journals (Sweden)

    B Dineshkumar

    2015-01-01

    Full Text Available Carbon nanotubes (CNTs are advanced nano-carrier for delivery of drugs especially anti-cancer drugs. In the field of CNT-based drug delivery system, both single-walled carbon nanotubes (SWCNTs and multi-walled nanotubes (MWCNTs can be used for targeting anticancer drugs in tissues and organs, where the high therapeutic effect is necessary. Benefits of the carbon nanotubes (CNTs in drug delivery systems are; avoiding solvent usage and reducing the side effects. Therefore, the present review article described about achievement of SWCNTs and MWCNTs to deliver the anticancer drugs with different cancerous cell lines.

  12. Single-walled and multi-walled carbon nanotubes based drug delivery system: Cancer therapy: A review.

    Science.gov (United States)

    Dineshkumar, B; Krishnakumar, K; Bhatt, A R; Paul, D; Cherian, J; John, A; Suresh, S

    2015-01-01

    Carbon nanotubes (CNTs) are advanced nano-carrier for delivery of drugs especially anti-cancer drugs. In the field of CNT-based drug delivery system, both single-walled carbon nanotubes (SWCNTs) and multi-walled nanotubes (MWCNTs) can be used for targeting anticancer drugs in tissues and organs, where the high therapeutic effect is necessary. Benefits of the carbon nanotubes (CNTs) in drug delivery systems are; avoiding solvent usage and reducing the side effects. Therefore, the present review article described about achievement of SWCNTs and MWCNTs to deliver the anticancer drugs with different cancerous cell lines.

  13. Epidermal electronic systems for sensing and therapy

    Science.gov (United States)

    Lu, Nanshu; Ameri, Shideh K.; Ha, Taewoo; Nicolini, Luke; Stier, Andrew; Wang, Pulin

    2017-04-01

    Epidermal electronic system is a class of hair thin, skin soft, stretchable sensors and electronics capable of continuous and long-term physiological sensing and clinical therapy when applied on human skin. The high cost of manpower, materials, and photolithographic facilities associated with its manufacture limit the availability of disposable epidermal electronics. We have invented a cost and time effective, completely dry, benchtop "cut-and-paste" method for the green, freeform and portable manufacture of epidermal electronics within minutes. We have applied the "cut-and-paste" method to manufacture epidermal electrodes, hydration and temperature sensors, conformable power-efficient heaters, as well as cuffless continuous blood pressure monitors out of metal thin films, two-dimensional (2D) materials, and piezoelectric polymer sheets. For demonstration purpose, we will discuss three examples of "cut-and-pasted" epidermal electronic systems in this paper. The first will be submicron thick, transparent epidermal graphene electrodes that can be directly transferred to human skin like a temporary transfer tattoo and can measure electrocardiogram (ECG) with signal-to-noise ratio and motion artifacts on par with conventional gel electrodes. The second will be a chest patch which houses both electrodes and pressure sensors for the synchronous measurements of ECG and seismocardiogram (SCG) such that beat-to-beat blood pressure can be inferred from the time interval between the R peak of the ECG and the AC peak of the SCG. The last example will be a highly conformable, low power consumption epidermal heater for thermal therapy.

  14. Multiparameter fiber optic sensing system for monitoring enhanced geothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Challener, William A

    2014-12-04

    The goal of this project was to design, fabricate and test an optical fiber cable which supports multiple sensing modalities for measurements in the harsh environment of enhanced geothermal systems. To accomplish this task, optical fiber was tested at both high temperatures and strains for mechanical integrity, and in the presence of hydrogen for resistance to darkening. Both single mode (SM) and multimode (MM) commercially available optical fiber were identified and selected for the cable based on the results of these tests. The cable was designed and fabricated using a tube-within-tube construction containing two MM fibers and one SM fiber, and without supporting gel that is not suitable for high temperature environments. Commercial fiber optic sensing instruments using Raman DTS (distributed temperature sensing), Brillouin DTSS (distributed temperature and strain sensing), and Raleigh COTDR (coherent optical time domain reflectometry) were selected for field testing. A microelectromechanical systems (MEMS) pressure sensor was designed, fabricated, packaged, and calibrated for high pressure measurements at high temperatures and spliced to the cable. A fiber Bragg grating (FBG) temperature sensor was also spliced to the cable. A geothermal well was selected and its temperature and pressure were logged. The cable was then deployed in the well in two separate field tests and measurements were made on these different sensing modalities. Raman DTS measurements were found to be accurate to ±5°C, even with some residual hydrogen darkening. Brillouin DTSS measurements were in good agreement with the Raman results. The Rayleigh COTDR instrument was able to detect some acoustic signatures, but was generally disappointing. The FBG sensor was used to determine the effects of hydrogen darkening, but drift over time made it unreliable as a temperature or pressure sensor. The MEMS sensor was found to be highly stable and accurate to better than its 0.1% calibration.

  15. Bioelectronic Device Mimicking Human Sensory System based on Nanovesicle-Carbon Nanotube Hybrid Structure

    Science.gov (United States)

    Kim, Daesan; Jin, Hye; Lee, San; Kim, Tae; Park, Juhun; Song, Hyun; Park, Tai; Hong, Seunghun

    2013-03-01

    We have developed a nanovesicle-based bioelectronic nose (NBN) that could mimic the receptor-mediated signal transmission of human olfactory systems and recognize a specific odorant. The NBN was comprised of a single-walled carbon nanotube (CNT)-based field effect transistor and cell-derived nanovesicles containing human olfactory receptors and calcium ion signal pathways. Importantly, the NBN took advantages of cell signal pathways for sensing signal amplification. It enabled ~100 times higher sensitivity than that of previous bioelectronic noses based on only olfactory receptor protein and CNT transistors. The NBN sensors exhibited a high sensitivity of 1 fM detection limit and a human-like selectivity with single-carbon-atomic resolution. Furthermore, these sensors could mimic a receptor-mediated cellular signal transmission in live cells. This versatile sensor platform should be useful for the study of molecular recognition and biological processes on cell membranes and also for various practical applications such as food conditioning and medical diagnostics.

  16. Carbon nanotube torsional springs for regenerative braking systems

    Science.gov (United States)

    Liu, Sanwei; Martin, Corbin; Lashmore, David; Schauer, Mark; Livermore, Carol

    2015-10-01

    The modeling and demonstration of large stroke, high energy density and high power density torsional springs based on carbon nanotube (CNT) yarns is reported, as well as their application as energy-storing actuators for regenerative braking systems. An originally untwisted CNT yarn is cyclically loaded and unloaded in torsion, with the maximum rotation angle increasing incrementally until failure. The measured average extractable energy density values are 2.9 kJ kg-1  ±  1.2 kJ kg-1 and 3.4 kJ kg-1  ±  0.4 kJ kg-1 for 1-ply CNT yarns and 2-ply CNT yarns, respectively. Additionally, a regenerative braking system is demonstrated to capture the kinetic energy of a wheel and store it as elastic energy in twisted CNT yarns. When the yarn’s twist is released, the stored energy reaccelerates the wheel. The measured energy and mean power densities of the CNT yarns in the simple regenerative braking setup are on average 3.3 kJ kg-1 and 0.67 kW kg-1, respectively, with maximum measured values of up to 4.7 kJ kg-1 and 1.2 kW kg-1, respectively. A slightly lower energy density of up to 1.2 kJ kg-1 and a 0.29 kW kg-1 mean power density are measured for CNT yarns in a more complex setup that mimics a unidirectional rotating regenerative braking mechanism.

  17. Gas sensing properties of branched carbon nanotube-based structures using a novel low voltage emission.

    Science.gov (United States)

    Darbari, S; Azimi, S; Abdi, Y; Mohajerzadeh, S

    2012-11-01

    Branched carbon nanostructures have been successfully grown on interdigital comb-like structures for a gas sensing application. Field emission scanning electron microscopy has been utilized to investigate the morphology and structure of the grown nanostructures at different stages of growth process. Tunneling current of the fabricated sensor has been measured when a monotonically increasing voltage is applied between the electrodes. The effect of exposure to three different gases on the measured current has been studied. A data processing on the measured current voltage characteristics results in the evolution of various peaks at distinct voltages which depends on the type of the gas.

  18. Hybrid optical-electrochemical electronic nose system based on Zn-porphyrin and multi-walled carbon nanotube composite.

    Science.gov (United States)

    Kladsomboon, Sumana; Lutz, Mario; Pogfay, Tawee; Puntheeranurak, Theeraporn; Kerdcharoen, Teerakiat

    2012-07-01

    In this work, we have enhanced the capability of an e-nose system based on combined optical and electrochemical transduction within a single gas sensor array. The optical part of this e-nose is based on detection of the absorption changes of light emitted from eight light emitting diodes (LEDs) as measured by a CMOS photo-detector. The electrochemical part works by measuring the change in electrical resistivity of the sensing materials upon contact with the sample vapor. Zinc-5,10,15,20-tetra-phenyl-21H,23H-porphyrin (ZnTPP) and multi-walled carbon nanotube (MWCNT) composite was used as the sensing materials based on its good optoelectronic properties. This sensing layer was characterized by UV-Vis spectroscopy and atomic force microscope and tested with various VOC vapors. Density functional theory (DFT) calculations were performed to investigate the electronic properties and interaction energies between ZnTPP and analyte molecules. It can be clearly seen that this hybrid optical-electrochemical electronic nose system can classify the vapor of different volatile organic compounds.

  19. The impact mitigation of a heterojunction nanotube-water system: behavior and mechanism.

    Science.gov (United States)

    Hu, Dayong; Jiang, Hanlin; Meng, Kangpei; Xu, Jun; Lu, Weiyi

    2016-03-14

    A novel nanofluidic impact protection system is introduced in this paper, consisting of hydrophobic heterojunction carbon nanotubes (HCNTs) and water molecules. When the capillary resistance of the nanopores is overcome, water molecules can infiltrate into nanopores such as to convert external impact energy into excessive surface energy. A model of a single HCNT with water molecules in a reservoir is established and validated. The effects of several dominant parameters (e.g., nanopore size, impact velocity) are evaluated, and the potential mechanism is illustrated. The effect of the carbon nanotube structure on the nanofluidic behavior of the HCNT-water system is investigated. Results reveal that the segment of carbon nanotubes close to the water reservoir determines the energy absorption efficiency of the system.

  20. Carbon nanotube-based superconducting and ferromagnetic hybrid systems

    NARCIS (Netherlands)

    Man, H.T.

    2006-01-01

    Carbon Nanotubes are molecules with exceptional physical properties that are most useful for applications in the growing field of nanotechnology. In addition, because of its special electrical properties, they are extremely useful for experiments on the fundamental properties of one-dimensional elec

  1. Coaxial electrospinning of WO3 nanotubes functionalized with bio-inspired Pd catalysts and their superior hydrogen sensing performance

    Science.gov (United States)

    Choi, Seon-Jin; Chattopadhyay, Saptarshi; Kim, Jae Jin; Kim, Sang-Joon; Tuller, Harry L.; Rutledge, Gregory C.; Kim, Il-Doo

    2016-04-01

    Macroporous WO3 nanotubes (NTs) functionalized with nanoscale catalysts were fabricated using coaxial electrospinning combined with sacrificial templating and protein-encapsulated catalysts. The macroporous thin-walled nanotubular structures were obtained by introducing colloidal polystyrene (PS) particles to a shell solution of W precursor and poly(vinylpyrrolidone). After coaxial electrospinning with a core liquid of mineral oil and subsequent calcination, open pores with an average diameter of 173 nm were formed on the surface of WO3 NTs due to decomposition of the PS colloids. In addition, catalytic Pd nanoparticles (NPs) were synthesized using bio-inspired protein cages, i.e., apoferritin, and uniformly dispersed within the shell solution and subsequently on the WO3 NTs. The resulting Pd functionalized macroporous WO3 NTs were demonstrated to be high performance hydrogen (H2) sensors. In particular, Pd-functionalized macroporous WO3 NTs exhibited a very high H2 response (Rair/Rgas) of 17.6 at 500 ppm with a short response time. Furthermore, the NTs were shown to be highly selective for H2 compared to other gases such as carbon monoxide (CO), ammonia (NH3), and methane (CH4). The results demonstrate a new synthetic method to prepare highly porous nanotubular structures with well-dispersed nanoscale catalysts, which can provide improved microstructures for chemical sensing.Macroporous WO3 nanotubes (NTs) functionalized with nanoscale catalysts were fabricated using coaxial electrospinning combined with sacrificial templating and protein-encapsulated catalysts. The macroporous thin-walled nanotubular structures were obtained by introducing colloidal polystyrene (PS) particles to a shell solution of W precursor and poly(vinylpyrrolidone). After coaxial electrospinning with a core liquid of mineral oil and subsequent calcination, open pores with an average diameter of 173 nm were formed on the surface of WO3 NTs due to decomposition of the PS colloids. In addition

  2. Vertically aligned multiwalled carbon nanotubes for pressure, tactile and vibration sensing

    Science.gov (United States)

    Yilmazoglu, O.; Popp, A.; Pavlidis, D.; Schneider, J. J.; Garth, D.; Schüttler, F.; Battenberg, G.

    2012-03-01

    We report a simple method for the micro-nano integration of flexible, vertically aligned multiwalled CNT arrays sandwiched between a top and bottom carbon layer via a porous alumina (Al2O3) template approach. The electromechanical properties of the flexible CNT arrays have been investigated under mechanical stress conditions. First experiments show highly sensitive piezoresistive sensors with a resistance decrease of up to ˜35% and a spatial resolution of <1 mm. The results indicate that these CNT structures can be utilized for tactile sensing components. They also confirm the feasibility of accessing and utilizing nanoscopic CNT bundles via lithographic processing. The method involves room-temperature processing steps and standard microfabrication techniques.

  3. Immobilization and Characterization Of Glucose Oxidase on Single-Walled Carbon Nanotubes and Its Application to Sensing Glucose

    Institute of Scientific and Technical Information of China (English)

    LIU,Shu-Na; YIN,Ya-Jing; CAI,Chen-Xin

    2007-01-01

    The negatively charged(at pH 8.2)glucose oxidase(GOx,pl ca.4.2)was assembled onto the surface of single-walled carbon nanotubes(SWNT),which was covered(or wrapped)by a layer of positively charged polyelectrolyte poly(dimethyldiallylammonium chloride)(PDDA),via the electrostatic interaction forming GOx-PDDA-SWNT nanocomposites.Fourier transform infrared(FTIR),UV-Vis and electrochemical impedance spectroscopy (EIS)were used to characterize the growth processes of the nanocomposites.The results indicated that GOx retained its native secondary conformational structure after it was immobilized on the surface of PDDA-SWNT. A biosensor(Nation-GOx-PDDA-SWNT/GC)was developed by immobilization of GOx-PDDA-SWNT nanocomposites on the surface of glassy carbon(GC)electrode using Nation(5%)as a binder. The biosensor showed the electrocatalytic activity toward the oxidation of glucose under the presence of ferrocene monocarboxylic acid(FcM) as an electroactive mediator with a good stability,reproducibility and higher biological affinity.Under an optimal condition,the biosensor could be used to detection of glucose,presenting a typical characteristic of Michaelis-Menten kinetics with the apparent Michaelis-Menten constant of Kapp/M ca.4.5 mmol/L,with a linear range of the concentrafion of glucose from 0.5 to 5.5 mmol/L(with correlation coefficient of 0.999)and the detection Iimit of ca.83μmol/L(at a signal-to-noise ratio of 3). Thus the biosensor was useful in sensing the glucose concentration in serum since the normal glucose concentration in blood serum was around 4.6 mmol/L.The facile procedure of immobilizing GOx used in present work would promote the developments of electrochemical research for enzymes(proteins). biosensors,biofuel cells and other bioelectrochemical devices.

  4. Self-assembly of hierarchically ordered structures in DNA nanotube systems

    Science.gov (United States)

    Glaser, Martin; Schnauß, Jörg; Tschirner, Teresa; Schmidt, B. U. Sebastian; Moebius-Winkler, Maximilian; Käs, Josef A.; Smith, David M.

    2016-05-01

    The self-assembly of molecular and macromolecular building blocks into organized patterns is a complex process found in diverse systems over a wide range of size and time scales. The formation of star- or aster-like configurations, for example, is a common characteristic in solutions of polymers or other molecules containing multi-scaled, hierarchical assembly processes. This is a recurring phenomenon in numerous pattern-forming systems ranging from cellular constructs to solutions of ferromagnetic colloids or synthetic plastics. To date, however, it has not been possible to systematically parameterize structural properties of the constituent components in order to study their influence on assembled states. Here, we circumvent this limitation by using DNA nanotubes with programmable mechanical properties as our basic building blocks. A small set of DNA oligonucleotides can be chosen to hybridize into micron-length DNA nanotubes with a well-defined circumference and stiffness. The self-assembly of these nanotubes to hierarchically ordered structures is driven by depletion forces caused by the presence of polyethylene glycol. This trait allowed us to investigate self-assembly effects while maintaining a complete decoupling of density, self-association or bundling strength, and stiffness of the nanotubes. Our findings show diverse ranges of emerging structures including heterogeneous networks, aster-like structures, and densely bundled needle-like structures, which compare to configurations found in many other systems. These show a strong dependence not only on concentration and bundling strength, but also on the underlying mechanical properties of the nanotubes. Similar network architectures to those caused by depletion forces in the low-density regime are obtained when an alternative hybridization-based bundling mechanism is employed to induce self-assembly in an isotropic network of pre-formed DNA nanotubes. This emphasizes the universal effect inevitable

  5. CNT coated thread micro-electro-mechanical system for finger proprioception sensing

    Science.gov (United States)

    Shafi, A. A.; Wicaksono, D. H. B.

    2017-04-01

    In this paper, we aim to fabricate cotton thread based sensor for proprioceptive application. Cotton threads are utilized as the structural component of flexible sensors. The thread is coated with multi-walled carbon nanotube (MWCNT) dispersion by using facile conventional dipping-drying method. The electrical characterization of the coated thread found that the resistance per meter of the coated thread decreased with increasing the number of dipping. The CNT coated thread sensor works based on piezoresistive theory in which the resistance of the coated thread changes when force is applied. This thread sensor is sewed on glove at the index finger between middle and proximal phalanx parts and the resistance change is measured upon grasping mechanism. The thread based microelectromechanical system (MEMS) enables the flexible sensor to easily fit perfectly on the finger joint and gives reliable response as proprioceptive sensing.

  6. Gait Dynamics Sensing Using IMU Sensor Array System

    Directory of Open Access Journals (Sweden)

    Slavomir Kardos

    2017-01-01

    Full Text Available The article deals with a progressive approach in gait sensing. It is incorporated by IMU (Inertia Measurement Unit complex sensors whose field of acting is mainly the motion sensing in medicine, automotive and other industry, self-balancing systems, etc. They allow acquiring the position and orientation of an object in 3D space. Using several IMU units the sensing array for gait dynamics was made. Based on human gait analysis the 7-sensor array was designed to build a gait motion dynamics sensing system with the possibility of graphical interpretation of data from the sensing modules in real-time graphical application interface under the LabVIEW platform. The results of analyses can serve as the information for medical diagnostic purposes. The main control part of the system is microcontroller, whose function is to control the data collection and flow, provide the communication and power management.

  7. Synthesis of Stacked-Cup Carbon Nanotubes in a Metal Free Low Temperature System

    Science.gov (United States)

    Kimura, Yuki; Nuth, Joseph A.; Johnson, Natasha M.; Farmer, Kevin D.; Roberts, Kenneth P.; Hussaini, Syed R.

    2011-01-01

    Stacked-cup carbon nanotubes were formed by either Fischer-Tropsch type or Haber Bosch type reactions in a metal free system. Graphite particles were used as the catalyst. The samples were heated at 600 C in a gas mixture of CO 75 Torr, N2 75 Torr and H2 550 Torr for three days. Trans mission electron microscope analysis of the catalyst surface at the completion of the experiment recognized the growth of nanotubes. They were 10-50 nm in diameter and approximately 1 micrometer in length. They had a hollow channel of 5-20 nm in the center. The nanotubes may have grown on graphite surfaces by the CO disproportionation reaction and the surface tension of the carbon nucleus may have determined the diameter. Although, generally, the diameter of a carbon nanotube depends on the size of the cataly1ic particles, the diameter of the nanotubes on graphite particles was independent of the particle size and significantly confined within a narrow range compared with that produced using catalytic amorphous iron-silicate nanoparticles. Therefore, they must have an unknown formation process that is different than the generally accepted mechanism.

  8. Microfluidic Systems for Pathogen Sensing: A Review

    Directory of Open Access Journals (Sweden)

    Peter Ertl

    2009-06-01

    Full Text Available Rapid pathogen sensing remains a pressing issue today since conventional identification methodsare tedious, cost intensive and time consuming, typically requiring from 48 to 72 h. In turn, chip based technologies, such as microarrays and microfluidic biochips, offer real alternatives capable of filling this technological gap. In particular microfluidic biochips make the development of fast, sensitive and portable diagnostic tools possible, thus promising rapid and accurate detection of a variety of pathogens. This paper will provide a broad overview of the novel achievements in the field of pathogen sensing by focusing on methods and devices that compliment microfluidics.

  9. Microfluidic systems for pathogen sensing: a review.

    Science.gov (United States)

    Mairhofer, Jürgen; Roppert, Kriemhilt; Ertl, Peter

    2009-01-01

    Rapid pathogen sensing remains a pressing issue today since conventional identification methodsare tedious, cost intensive and time consuming, typically requiring from 48 to 72 h. In turn, chip based technologies, such as microarrays and microfluidic biochips, offer real alternatives capable of filling this technological gap. In particular microfluidic biochips make the development of fast, sensitive and portable diagnostic tools possible, thus promising rapid and accurate detection of a variety of pathogens. This paper will provide a broad overview of the novel achievements in the field of pathogen sensing by focusing on methods and devices that compliment microfluidics.

  10. A catalog system for remote-sensing data

    Science.gov (United States)

    Singh, R. S.; Scherz, J. P.

    1974-01-01

    The Practical System for Cataloging, Indexing, and Retrieval of Remote Sensing Data developed by the Interdisciplinary Remote Sensing Group at the University of Wisconsin consists of a card catalog, a site-index-map, a site-index-file, an industry-index-file, and a project-index-file. The system is designed for retrieval of remote-sensing data which include imagery, magnetic tapes, flight logs, maps, ground-truth reports, and research reports containing raw data. It can be operated by conventional library methods, but provision has been made for digitizing the system for computer retrieval.

  11. Controllable nanoscale rotating actuator system based on carbon nanotube and graphene

    Science.gov (United States)

    Huang, Jianzhang; Han, Qiang

    2016-04-01

    A controllable nanoscale rotating actuator system consisting of a double carbon nanotube and graphene driven by a temperature gradient is proposed, and its rotating dynamics performance and driving mechanism are investigated through molecular dynamics simulations. The outer tube exhibits stable pure rotation with certain orientation under temperature gradient and the steady rotational speed rises as the temperature gradient increases. It reveals that the driving torque is caused by the difference of atomic van der Waals potentials due to the temperature gradient and geometrical features of carbon nanotube. A theoretical model for driving torque is established based on lattice dynamics theory and its predicted results agree well with molecular dynamics simulations. Further discussion is taken according to the theoretical model. The work in this study would be a guide for design and application of controllable nanoscale rotating devices based on carbon nanotubes and graphene.

  12. Confinement of Mg-MgH2 systems into carbon nanotubes changes hydrogen sorption energetics.

    Science.gov (United States)

    Liang, Jian-jie; Kung, W-C Paul

    2005-09-29

    The density functional theory (DFT) method was used to study the effect of nanoconfinement on the energetics of Mg-MgH2 systems. Varying levels of loading of the Mg/MgH2 particles into a (10,10) carbon nanotube were examined, and the corresponding energetics were computed. A clear trend was observed that, as the level of loading increases (increasing confinement), the net energy change in the hydrogen sorption/desorption processes decreases to a significant level when the loading approaches the maximum. The confinement was found not to depend on the tube length of the confining nanotubes.

  13. Cavitation dispersion of carbon nanotubes and modification of cement systems

    Directory of Open Access Journals (Sweden)

    GUSEV Boris Vladimirovich

    2014-12-01

    Full Text Available The most common research areas in construction material science deals with the development of new efficient methods to increase strength properties of materials. One of such methods is modification of composite matrices with carbon nanotubes. The characteristics of nanomodified concretes to a great extent depend on selected method of introduction of carbon nanotubes into material. The predispersion of CNT in mixing water with plasticizing additive through ultrasound impact on the environment with colloid and other types of particles including nanoparticles is the most frequently used scientific method which provides even distribution of nanoparticles in cement. In some works the separation of agglomerated CNT in suspension was conducted by means of ultrasound treatment. The further analysis showed that the main drawbacks of ultrasound dispersion are high energy output and low performance. That causes inconvenience for application of them in manufacturing process. The methods of cavitation dispersion which were developed in the late 90ies in the XXI century today are becoming commonly used in practice. The work presents the results of dispersion of multi-layer nanotubes performed on the hydrodynamic cavitation equipment. It was determined that the use of such equipment makes it possible to produce stable and even carbon dispersions and to introduce and distribute them uniformly in concrete in the same way as in the case when ultrasound treatment is performed. The advantages of this technology are considerable decrease of energy consumption and possibility to treat enormous amounts of liquids which are necessary for modification of concrete in real production process.

  14. Hierarchical Assembly of α-Fe2O3 Nanorods on Multiwall Carbon Nanotubes as a High-Performance Sensing Material for Gas Sensors.

    Science.gov (United States)

    Dai, Mingjun; Zhao, Liupeng; Gao, Hongyu; Sun, Peng; Liu, Fengmin; Zhang, Sean; Shimanoe, Kengo; Yamazoe, Noboru; Lu, Geyu

    2017-03-15

    This paper presents a facile hydrolysis reaction and annealing for preparing a novel hierarchical nanoheterostructure via assembly of α-Fe2O3 nanorods onto multiwall carbon nanotubes (MWCNTs) backbones. The as-synthesized nanocomposites were characterized using XRD (X-ray diffraction), FESEM (Field emission scanning electron microscopy), TEM (Transmission electron microscopy), XPS (X-ray photoelectron spectroscopy) and BET (Surface Area and Porosity System). The observations showed uniform α-Fe2O3 nanorods approximately 100-200 nm in length and 50-100 nm in diameter that were hierarchically assembled onto the surface of the MWCNTs. The formation of the heterostructure was investigated by observing the evolution of the microstructure of the products at different reaction times. The X-ray photoelectron spectra (XPS) showed that the ability of the absorbing oxygen was enhanced by the formation of the heterostructure composites. Moreover, as a proof-of-concept presentation, the novel CNTs@α-Fe2O3 hierarchical heterostructure acted as a gas sensitive material. Significantly, the composites exhibited excellent sensing properties for acetone with high sensitivity, exceptional selectivity and good reproducibility. The response of the CNTs@α-Fe2O3 sensor to 100 ppm acetones at 225 °C was nearly 35, which was superior to the single α-Fe2O3 nanorods with a response of 16, and the detection limit of the sensor was 500 ppb. The enhanced properties were mainly attributed to the unique structure and p-n heterojunction between the CNTs and the α-Fe2O3 nanorods.

  15. Sensing rich design of drive trains for mechatronic systems

    Science.gov (United States)

    Tomizuka, Masayoshi

    2006-03-01

    In this paper, the advantages of sensing rich approaches to the design of mechatronic systems are explored. Such advantages include enhanced system performance, flexible operation of the system and reduced operational costs. Some advantages of the sensing rich design will be elaborated for the power transmission mechanism or drive train under servo control. The drive train is a fundamental element of any motion control system. The sensing rich design is based on measurements of positions and accelerations at multiple points of a drive train. These measurements improve the performance of drive train servo systems in terms of speed, positioning accuracy and vibration suppression. For example, the Kinematic Kalman filter (KKF) may be used in sensing rich designs. KKF accomplishes robust estimation of the velocity in the presence of parameter uncertainties and disturbances based on the accelerometer and the encoder.

  16. Effect of oxygen plasma treatment on horizontally aligned carbon nanotube thin film as pH-sensing membrane of extended-gate field-effect transistor

    Science.gov (United States)

    Wang, Kuang-Yu; Tsai, Wan-Lin; Yang, Po-Yu; Chou, Chia-Hsin; Li, Yu-Ren; Liao, Chan-Yu; Cheng, Huang-Chung

    2015-04-01

    The high-performance pH-sensing membrane of extended-gate field-effect transistors (EGFET) composed of high-conductivity horizontally aligned carbon nanotube thin films (HACNTFs) after oxygen plasma treatment is successfully demonstrated. The 10-µm-wide catalytic metal lines with 60 µm interspace produced CNT vertical plates, and the plates were mechanically pulled down and densified to form HACNTFs. A large amount of oxygen-containing functional groups are decorated on the CNTs after the oxygen plasma treatment. These functional groups act as the sensing sites and respond to the H+ or OH- ions in solutions with different pH values. Therefore, these functionalized HACNTFs as pH-EGFET-sensing membranes can achieve a high voltage sensitivity of 40 mV/pH and high current sensitivity of 0.78 µA1/2/pH. Moreover, large linearity of 0.998 is measured in a wide sensing range from pH 1 to 13. These results reveal that the oxygen plasma treatment is an effective way to improve the CNT-sensing characteristics in pH-EGFET sensors.

  17. Cooperative Spectrum Sensing and Localization in Cognitive Radio Systems Using Compressed Sensing

    Directory of Open Access Journals (Sweden)

    Wael Guibène

    2013-01-01

    Full Text Available We propose to fuse two main enabling features in cognitive radio systems (CRS: spectrum sensing and location awareness in a single compressed sensing based formalism. In this way, we exploit sparse characteristics of primary units to be detected, both in terms of spectrum used and location occupied. The compressed sensing approach also allows to overcome hardware limitations, in terms of the incapacity to acquire measurements and signals at the Nyquist rate when the spectrum to be scanned is large. Simulation results for realistic network topologies and different compressed sensing reconstruction algorithms testify to the performance and the feasibility of the proposed technique to enable in a single formalism the two main features of cognitive sensor networks.

  18. 3D-printed poly(vinylidene fluoride)/carbon nanotube composites as a tunable, low-cost chemical vapour sensing platform.

    Science.gov (United States)

    Kennedy, Z C; Christ, J F; Evans, K A; Arey, B W; Sweet, L E; Warner, M G; Erikson, R L; Barrett, C A

    2017-05-04

    We report the production of flexible, highly-conductive poly(vinylidene fluoride) (PVDF) and multi-walled carbon nanotube (MWCNT) composites as filament feedstock for 3D printing. This account further describes, for the first time, fused deposition modelling (FDM) derived 3D-printed objects with chemiresistive properties in response to volatile organic compounds. The typically prohibitive thermal expansion and die swell characteristics of PVDF were minimized by the presence of MWCNTs in the composites enabling straightforward processing and printing. The nanotubes form a dispersed network as characterized by helium ion microscopy, contributing to excellent conductivity (∼3 × 10(-2) S cm(-1)). The printed composites contain little residual metal particulate relative to parts from commercial PLA-nanocomposite material visualized by micro-X-ray computed tomography (μ-CT) and corroborated with thermogravimetric analysis. Printed sensing strips, with MWCNT loadings up to 15% mass, function as reversible vapour sensors with the strongest responses arising with organic compounds capable of readily intercalating and subsequently swelling the PVDF matrix (acetone and ethyl acetate). A direct correlation between MWCNT concentration and resistance change was also observed, with larger responses (up to 161% after 3 minutes) being generated with decreased MWCNT loadings. These findings highlight the utility of FDM printing in generating low-cost sensors that respond strongly and reproducibly to target vapours. Furthermore, the sensors can be easily printed in different geometries, expanding their utility to wearable form factors. The proposed formulation strategy may be tailored to sense diverse sets of vapour classes through structural modification of the polymer backbone and/or functionalization of the nanotubes within the composite.

  19. 3D-printed poly(vinylidene fluoride)/carbon nanotube composites as a tunable, low-cost chemical vapour sensing platform

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, Z. C.; Christ, J. F.; Evans, K. A.; Arey, B. W.; Sweet, L. E.; Warner, M. G.; Erikson, R. L.; Barrett, C. A.

    2017-01-01

    We report the production of flexible, highly-conductive poly(vinylidene flouride) (PVDF) and multi-walled carbon nanotube (MWCNT) composites as filament feedstock for 3D-printing. This account further describes, for the first-time, fused deposition modelling (FDM) derived 3D-printed objects with chemiresistive properties in response to volatile organic compounds. The typically prohibitive thermal expansion and die swell characteristics of PVDF were minimized by the presence of MWCNTs in the composites enabling straightforward processing and printing. The nanotubes form a dispersed network as characterized by helium ion microscopy, contributing to excellent conductivity (1 x 10-2 S / cm). The printed composites contain little residual metal particulate relative to parts from commercial PLA-nanocomposite material visualized by micro X-ray computed tomography (μ-CT) and corroborated with thermogravimetric analysis. Printed sensing strips, with MWCNT loadings up to 15 % mass, function as reversible vapour sensors with the strongest responses arising with organic compounds capable of readily intercalating, and subsequently swelling the PVDF matrix (acetone and ethyl acetate). A direct correlation between MWCNT concentration and resistance change was also observed, with larger responses (up to 161 % after 3 minutes) generated with decreased MWCNT loadings. These findings highlight the utility of FDM printing in generating low-cost sensors that respond strongly and reproducibly to target vapours. Furthermore, the sensors can be easily printed in different geometries, expanding their utility to wearable form factors. The proposed formulation strategy may be tailored to sense diverse sets of vapour classes through structural modification of the polymer backbone and/or functionalization of the nanotubes within the composite.

  20. The effects of carbon nanotube addition and oxyfluorination on the glucose-sensing capabilities of glucose oxidase-coated carbon fiber electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Im, Ji Sun; Yun, Jumi; Kim, Jong Gu [Department of Fine Chemical Engineering and Applied Chemistry, BK21-E2 M, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Bae, Tae-Sung [Department of Fine Chemical Engineering and Applied Chemistry, BK21-E2 M, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Korea Basic Science Institute (KBSI), Jeonju 561-756 (Korea, Republic of); Lee, Young-Seak, E-mail: youngslee@cnu.ac.kr [Department of Fine Chemical Engineering and Applied Chemistry, BK21-E2 M, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2012-01-15

    Glucose-sensing electrodes were constructed from carbon fibers by electrospinning and heat treatment. By controlling the pore size, the specific surface area and pore volume of the electrospun carbon fibers were increased for efficient immobilization of the glucose oxidase. Carbon nanotubes were embedded as an electrically conductive additive to improve the electrical property of the porous carbon fibers. In addition, the surface of the porous carbon fibers was modified with hydrophilic functional groups by direct oxyfluorination to increase the affinity between the hydrophobic carbon surface and the hydrophilic glucose oxidase molecules. The porosity of the carbon fibers was improved significantly with approximately 28- and 35-fold increases in the specific surface area and pore volume, respectively. The number of chemical bonds between carbon and oxygen were increased with higher oxygen content during oxyfluorination based on the X-ray photoelectron spectroscopy results. Glucose sensing was carried out by current voltagram and amperometric methods. A high-performance glucose sensor was obtained with high sensitivity and rapid response time as a result of carbon nanotube addition, physical activation and surface modification. The mechanism of the highly sensitive prepared glucose sensor was modeled by an enzyme kinetics study using the Michaelis-Menten equation.

  1. Temperature-dependent electrical and photo-sensing properties of horizontally-oriented carbon nanotube networks synthesized by sandwich-growth microwave plasma chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Teng, I-Ju [Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Hsu, Hui-Lin [Department of Electrical and Computer Engineering, University of Toronto, Toronto M5S 3G4 (Canada); Jian, Sheng-Rui, E-mail: srjian@gmail.com [Department of Materials Science and Engineering, I-Shou University, Kaohsiung 84041, Taiwan (China); Wang, Li-Chun; Chen, Kai-Ling [Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Kuo, Cheng-Tzu, E-mail: kurt.kuotw@gmail.com [Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Pan, Fu-Ming [Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Wang, Wei-Hsiang [Teraxtal Technology Corporation, Hsinchu 30075, Taiwan (China); Juang, Jenh-Yih [Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan (China)

    2013-02-01

    The electrical and photo-sensing properties of horizontally-oriented interconnected carbon nanotube networks (CNT-NWs) prepared by means of a microwave plasma chemical vapor deposition sandwich-growth process are investigated. The temperature-dependent dark and illuminated current–voltage and transfer characteristics of CNT-NW-assisted devices are measured. Results show that the current–voltage characteristics of the devices exhibit nonlinear behavior, and the current can be further modulated by a gate voltage, revealing p-type semiconducting behavior with a device mobility of ∼ 14.5 cm{sup 2}/V·s and an on-off current ratio of ∼ 10{sup 3}. Moreover, when the CNT-NW-assisted devices are irradiated with 1.25–25 μm infrared (IR) from 300 to 11 K, the photo currents increase approximately 1.1- to 2.7-fold compared to the dark currents at ± 2 V bias voltage. Such results demonstrate that the presented CNT-NWs have high potential for IR photo-sensor applications. - Highlights: ► Horizontally-oriented interconnected carbon nanotube networks (CNT-NWs) were grown. ► A microwave plasma chemical vapor deposition sandwich-growth process was employed. ► Temperature-dependent electrical and photo-sensing properties were investigated. ► Devices based on CNT-NWs exhibit promising transistor characteristics. ► CNT-NWs are capable to detect light in the infrared wavelength range.

  2. VisionSense - An advanced lateral collision warning system

    OpenAIRE

    Dijck, T.; Heijden, van der, M.C.

    2005-01-01

    VisionSense is an advanced driver assistance system which combines a lateral collision warning system with vehicle-to-vehicle communication. This paper shows the results of user needs assessment and traffic safety modelling of VisionSense. User needs were determined by means of a Web-based survey. The results show, that VisionSense is most appreciated when it uses a light signal to warn the driver in a possibly hazardous situation on a highway. The willingness to pay is estimated at 300 Euros...

  3. Robotic Tactile Sensing Technologies and System

    CERN Document Server

    Dahiya, Ravinder S

    2013-01-01

    Future robots are expected to work closely and interact safely with real-world objects and humans alike. Sense of touch is important in this context, as it helps estimate properties such as shape, texture, hardness, material type and many more; provides action related information, such as slip detection; and helps carrying out actions such as rolling an object between fingers without dropping it. This book presents an in-depth description of the solutions available for gathering tactile data, obtaining aforementioned tactile information from the data and effectively using the same in various robotic tasks. Better integration of tactile sensors on a robot’s body is prerequisite for the effective utilization of tactile data. For this reason, the hardware, software and application related issues (and resulting trade-offs) that must be considered to make tactile sensing an effective component of robotic platforms are discussed in-depth.To this end, human touch sensing has also been explored. The design hints co...

  4. A cross-functional nanostructured platform based on carbon nanotube-Si hybrid junctions: where photon harvesting meets gas sensing

    Science.gov (United States)

    Rigoni, F.; Pintossi, C.; Drera, G.; Pagliara, S.; Lanti, G.; Castrucci, P.; de Crescenzi, M.; Sangaletti, L.

    2017-03-01

    A combination of the functionalities of carbon nanotube (CNT)-Si hybrid heterojunctions is presented as a novel method to steer the efficiency of the photovoltaic (PV) cell based on these junctions, and to increase the selectivity and sensitivity of the chemiresistor gas sensor operated with the p-doped CNT layer. The electrical characteristics of the junctions have been tracked by exposing the devices to oxidizing (NO2) and reducing (NH3) molecules. It is shown that when used as PV cells, the cell efficiency can be reversibly steered by gas adsorption, providing a tool to selectively dope the p-type layer through molecular adsorption. Tracking of the current-voltage curve upon gas exposure also allowed to use these cells as gas sensors with an enhanced sensitivity as compared to that provided by a readout of the electrical signal from the CNT layer alone. In turn, the chemiresistive response was improved, both in terms of selectivity and sensitivity, by operating the system under illumination, as the photo-induced charges at the junction increase the p-doping of CNTs making them more sensitive to NH3 and less to NO2.

  5. Fluidic nanotubes and devices

    Science.gov (United States)

    Yang, Peidong; He, Rongrui; Goldberger, Joshua; Fan, Rong; Wu, Yiying; Li, Deyu; Majumdar, Arun

    2008-04-08

    Fluidic nanotube devices are described in which a hydrophilic, non-carbon nanotube, has its ends fluidly coupled to reservoirs. Source and drain contacts are connected to opposing ends of the nanotube, or within each reservoir near the opening of the nanotube. The passage of molecular species can be sensed by measuring current flow (source-drain, ionic, or combination). The tube interior can be functionalized by joining binding molecules so that different molecular species can be sensed by detecting current changes. The nanotube may be a semiconductor, wherein a tubular transistor is formed. A gate electrode can be attached between source and drain to control current flow and ionic flow. By way of example an electrophoretic array embodiment is described, integrating MEMs switches. A variety of applications are described, such as: nanopores, nanocapillary devices, nanoelectrophoretic, DNA sequence detectors, immunosensors, thermoelectric devices, photonic devices, nanoscale fluidic bioseparators, imaging devices, and so forth.

  6. Compressed Measurements Based Spectrum Sensing for Wideband Cognitive Radio Systems

    Directory of Open Access Journals (Sweden)

    Taha A. Khalaf

    2015-01-01

    Full Text Available Spectrum sensing is the most important component in the cognitive radio (CR technology. Spectrum sensing has considerable technical challenges, especially in wideband systems where higher sampling rates are required which increases the complexity and the power consumption of the hardware circuits. Compressive sensing (CS is successfully deployed to solve this problem. Although CS solves the higher sampling rate problem, it does not reduce complexity to a large extent. Spectrum sensing via CS technique is performed in three steps: sensing compressed measurements, reconstructing the Nyquist rate signal, and performing spectrum sensing on the reconstructed signal. Compressed detectors perform spectrum sensing from the compressed measurements skipping the reconstruction step which is the most complex step in CS. In this paper, we propose a novel compressed detector using energy detection technique on compressed measurements sensed by the discrete cosine transform (DCT matrix. The proposed algorithm not only reduces the computational complexity but also provides a better performance than the traditional energy detector and the traditional compressed detector in terms of the receiver operating characteristics. We also derive closed form expressions for the false alarm and detection probabilities. Numerical results show that the analytical expressions coincide with the exact probabilities obtained from simulations.

  7. Halloysite Nanotube Composited Thermo-responsive Hydrogel System for Controlled-release

    Institute of Scientific and Technical Information of China (English)

    林茜; 巨晓洁; 谢锐; 江明月; 魏竭; 褚良银

    2013-01-01

    Halloysite nanotube-composited thermo-responsive hydrogel system has been successfully developed for controlled drug release by copolymerization of N-isopropylacrylamide (NIPAM) with silane-modified halloysite nanotubes (HNT) through thermally initiated free-radical polymerization. With methylene blue as a model drug, thermo-responsive drug release results demonstrate that the drug release from the nanotubes in the composited hy-drogel can be well controlled by manipulating the environmental temperature. When the hydrogel network is swol-len at temperature below the lower critical solution temperature (LCST), drug releases steadily from lumens of the embedded nanotubes, whereas the drug release stops when hydrogel shrinks at temperature above the LCST. The release of model drug from the HNT-composited hydrogel matches well with its thermo-responsive volume phase transition, and shows characteristics of well controlled release. The design strategy and release results of the pro-posed novel HNT-composited thermo-responsive hydrogel system provide valuable guidance for designing respon-sive nanocomposites for controlled-release of active agents.

  8. Recent advances in carbon nanotubes as delivery systems for anticancer drugs.

    Science.gov (United States)

    Iannazzo, Daniela; Piperno, Anna; Pistone, Alessandro; Grassi, Giovanni; Galvagno, Signorino

    2013-01-01

    Problems associated with the administration of anticancer drugs, such as limited solubility, poor biodistribution,lack of selectivity, and healthy tissue damage, can be overcome by the implementation of drug delivery systems. A wide range of materials, including liposomes, microspheres, polymers and recently, carbon nanotubes (CNTs), have been investigated for delivering anticancer drugs on the purpose of reducing the number of necessary administrations, providing more localized and better use of the active agents, and increasing patient compliance. Carbon nanotubes (CNTs) have attracted particular attention as carriers of biologically relevant molecules due to their unique physical, chemical and physiological properties. The exact relationship between the physical-chemical properties of carbon nanotubes, their cell to-cell interactions, reactivity, and biological/systemic consequences are relevant issues and it is important to know suchinter-relationships beforehand to employ the benefits of these nanomaterials without the hazardous consequences. The purpose of this review is to present highlight of recent developments in the application of carbon nanotubes as cargoes for anti cancer drugs and in the diagnosis of cancer diseases.

  9. The peculiar electrical response of liquid crystal-carbon nanotube systems as seen by impedance spectroscopy

    Science.gov (United States)

    García-García, A.; Vergaz, R.; Algorri, J. F.; Geday, M. A.; Otón, J. M.

    2015-09-01

    Conductive nanoparticles, especially elongated ones such as carbon nanotubes, dramatically modify the electrical behavior of liquid crystal cells. These nanoparticles are known to reorient with liquid crystals in electric fields, causing significant variations of conductivity at minute concentrations of tens or hundreds ppm. The above notwithstanding, impedance spectroscopy of doped cells in the frequency range customarily employed by liquid crystal devices, 100 Hz-10 kHz, shows a relatively simple resistor/capacitor response where the components of the cell can be univocally assigned to single components of the electrical equivalent circuit. However, widening the frequency range up to 1 MHz or beyond reveals a complex behavior that cannot be explained with the same simple EEC. Moreover, the system impedance varies with the application of electric fields, their effect remaining after removing the field. Carbon nanotubes are reoriented together with liquid crystal reorientation when applying voltage, but barely reoriented back upon liquid crystal relaxation once the voltage is removed. Results demonstrate a remarkable variation in the impedance of the dielectric blend formed by liquid crystal and carbon nanotubes, the irreversible orientation of the carbon nanotubes and possible permanent contacts between electrodes.

  10. Development of smart sensing system for structural health monitoring

    Science.gov (United States)

    Lu, Kung-Chun; Loh, Chin-Hsiung; Weng, Jian Huang

    2010-04-01

    The objective of this paper is to upgrade a wireless sensing unit which can meet the following requirements: 1) Improvement of system powering and analog signal processing 2) Enhancement of signal resolution and provide reliable wireless communication data, 3) Enhance capability for continuous long-term monitoring. Based on the prototype of the wireless sensing unit developed by Prof. Lynch at the Stanford University, the following upgrading steps are summarized: 1. Reduce system noise by using SMD passive elements and preventing the coupling digital and analog circuits, and increasing the capacity of power. 2. Improve the ADC sampling resolution and accuracy with a higher resolution Analog-to-Digital Converter (ADC): a 24bits ADC with programmable gain amplifier. 3. Improve wireless communication by using the wireless radio 9XTend which supported by the router (Digi MESH) communication function using 900MHz frequency band. Based on the upgrade wireless sensing unit, verification of the new wireless sensing unit was conducted from the ambient vibration survey of a base-isolated building. This new upgrade wireless sensing unit can provide more reliable data for continuous structural health monitoring. Incorporated with the identification software (modified stochastic subspace identification method) the smart sensing system for SHM is developed.

  11. Analysis of Percolation Behavior of Electrical Conductivity of the Systems Based on Polyethers and Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    E.A. Lysenkov

    2016-03-01

    Full Text Available The basic theoretical models of electrical conductivity of polymer nanocomposites and their accordance to experimental results are analysed for the systems based on polyethers and carbon nanotubes using the methods of mathematical simulation. It is set that models which are based on the effective medium approximation do not take into account existence of percolation threshold and can’t be using for exact definition of experimental data. It is discovered that the Fourier model demonstrats a good accordance with an experiment, however it is applicable only for the systems in which a large increase of conductivity under reaching the percolation threshold is observed, that systems with low own conductivity. It is set that the best accordance to experimental data was shown by the Kirkpatrick model and the generalized McLachlan model, which, except for the percolation threshold, structural descriptions of clusters which are formed from carbon nanotubes take into account.

  12. ZnO Functionalization of Multi-walled Carbon Nanotubes for Methane Sensing at Single Parts Per Million Concentration Levels

    Science.gov (United States)

    This paper presents a novel atomic layer deposition (ALD) based ZnO functionalization of surface pre-treated multi-walled carbon nanotubes (MWCNTs) for highly sensitive methane chemoresistive sensors. The temperature optimization of the ALD process leads to enhanced ZnO nanopart...

  13. Making sense of enterprise systems in institutions

    DEFF Research Database (Denmark)

    Svejvig, Per; Jensen, Tina Blegind

    2013-01-01

    Whereas previous research provides a number of accounts of failure prone enterprise system (ES) implementations, empirical evidence of the re-implementation of an accounting system in a Scandinavian high-tech company shows how the system became highly integrated, accepted by its users, and well...... system travelled from a national to a local level, how the system moved from being highly customized to becoming a standard package and how the users’ enactment of the system reinforced existing institutional practices. Based on the findings, we frame our contributions into five lessons learned: (1...

  14. An off-the-shelf sensing system for physiological phosphates.

    Science.gov (United States)

    Mallet, Alie M; Liu, Yuanli; Bonizzoni, Marco

    2014-05-21

    An off-the-shelf supramolecular sensing system was designed to discriminate biologically relevant phosphates in neutral water using multivariate data analysis. The system is based on an indicator displacement assay comprising only two unmodified commercially available components: a dendritic poly-electrolyte and a common fluorescent dye. Effective discrimination of nucleotide diphosphates and inorganic diphosphate was achieved through principal component analysis (PCA).

  15. A Situated Cultural Festival Learning System Based on Motion Sensing

    Science.gov (United States)

    Chang, Yi-Hsing; Lin, Yu-Kai; Fang, Rong-Jyue; Lu, You-Te

    2017-01-01

    A situated Chinese cultural festival learning system based on motion sensing is developed in this study. The primary design principle is to create a highly interactive learning environment, allowing learners to interact with Kinect through natural gestures in the designed learning situation to achieve efficient learning. The system has the…

  16. Conceptual development of the immune system as a sixth sense.

    Science.gov (United States)

    Blalock, J Edwin; Smith, Eric M

    2007-01-01

    Understanding how and why the immune and nervous systems communicate in a bidirectional pathway has been fundamental to the development of the psychoneuroimmunology (PNI) field. This review will discuss some of the pivotal results that found the nervous and immune systems use a common chemical language for intra and inter-system communication. Specifically the nervous and immune systems produce a common set of peptide and nonpeptide neurotransmitters and cytokines that provides a common repertoire of receptors and ligands between the two systems. These studies led to the concept that through the sharing of ligands and receptors the immune system could serve as a sixth sense to detect things the body cannot otherwise hear, see, smell, taste or touch. Pathogens, tumors, and allergens are detected with great sensitivity and specificity by the immune system. As a sixth sense the immune system is a means to signal and mobilize the body to respond to these types of challenges. The paper will also review in a chronological manner some of the PNI-related studies important to validating the sixth sense concept. Finally, the review will suggest ways to apply the new found knowledge of the sixth sense to understanding a placebo effect and developing new therapeutic approaches for treatment of human diseases.

  17. A Situated Cultural Festival Learning System Based on Motion Sensing

    Science.gov (United States)

    Chang, Yi-Hsing; Lin, Yu-Kai; Fang, Rong-Jyue; Lu, You-Te

    2017-01-01

    A situated Chinese cultural festival learning system based on motion sensing is developed in this study. The primary design principle is to create a highly interactive learning environment, allowing learners to interact with Kinect through natural gestures in the designed learning situation to achieve efficient learning. The system has the…

  18. Sol-gel derived multiwalled carbon nanotubes ceramic electrode modified with molecularly imprinted polymer for ultra trace sensing of dopamine in real samples

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, Bhim Bali, E-mail: prof.bbpd@yahoo.com [Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221 005 (India); Kumar, Deepak; Madhuri, Rashmi; Tiwari, Mahavir Prasad [Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221 005 (India)

    2011-08-01

    Highlights: > MWCNTs-CE was prepared by silane acrylate which provides a nanometer thin MIP film. > The sensor was modified by iniferter and MIP using 'surface grafting-from approach'. > A comparative study was performed between differentially designed ceramic electrodes. > The sensor can detect dopamine in real samples with LODs (0.143-0.154 ng mL{sup -1}). - Abstract: A new class of composite electrodes made of sol-gel derived ceramic-multiwalled carbon nanotubes is used for the growth of a nanometer thin film adopting 'surface grafting-from approach'. For this the multiwalled carbon nanotubes-ceramic electrode surface is first modified with an iniferter (benzyl N,N-diethyldithiocarbamate) and then dopamine imprinted polymer, under UV irradiation, for differential pulse anodic stripping voltammetric sensing of dopamine in aqueous, blood serum, cerebrospinal fluid, and pharmaceutical samples (detection limit 0.143-0.154 ng mL{sup -1}, 3{sigma}), without any cross reactivity, interferences and false-positive contributions. Such composite electrodes offer higher stability, electron kinetics, and renewable porous surface of larger electroactive area (with insignificant capacitance) than carbon ceramic electrodes. Additional cyclic voltammetry (stripping mode) and chronocoulometry experiments were performed to explore electrodics and kinetics of electro-oxidation of dopamine.

  19. Effective mass sensing using optomechanically induced transparency in microresonator system

    CERN Document Server

    Gao, Yong-Pan; Cao, Cong; Mi, Si-Chen; Yang, Daquan; Zhang, Yong; Wang, Chuan

    2016-01-01

    Detecting and weighing the individual nanoparticles is an important approach to study the behavior and properties of single particles. Here we illustrate an effective mass sensing scheme using optomechanical resonator system. Based on the optomechanically induced transparency phenomenon, a Stokes field reference approach is used to sense the mass of the particle on the microresonator. The field intensity of the transmission field will be changed by the effect of the particle which avoids the limits of decay induced spectral width in the resonance shift detection. Exploiting the perturbation method, we theoretically evaluated the dynamical behavior of the system, and achieved the femtogram level mass sensing without the need for high cavity Q-value, and strong coupling strength in the optomechanically system.

  20. On prilled Nanotubes-in-Microgel Oral Systems for protein delivery.

    Science.gov (United States)

    de Kruif, Jan Kendall; Ledergerber, Gisela; Garofalo, Carla; Fasler-Kan, Elizaveta; Kuentz, Martin

    2016-04-01

    Newly discovered active macromolecules are highly promising for therapy, but poor bioavailability hinders their oral use. Microencapsulation approaches, such as protein prilling into microspheres, may enable protection from gastrointestinal (GI) enzymatic degradation. This would increase bioavailability mainly for local delivery to GI lumen or mucosa. This work's purpose was to design a novel architecture, namely a Nanotubes-in-Microgel Oral System, by prilling for protein delivery. Halloysite nanotubes (HNT) were selected as orally acceptable clay particles and their lumen was enlarged by alkaline etching. This chemical modification increased the luminal volume to a mean of 216.3 μL g(-1) (+40.8%). After loading albumin as model drug, the HNT were entrapped in microgels by prilling. The formation of Nanoparticles-in-Microsphere Oral System (NiMOS) yielded entrapment efficiencies up to 63.2%. NiMOS shape was spherical to toroidal, with a diameter smaller than 320 μm. Release profiles depended largely on the employed system and HNT type. Protein stability was determined throughout prilling and after in vitro enzymatic degradation. Prilling did not harm protein structure, and NiMOS demonstrated higher enzymatic protection than pure nanotubes or microgels, since up to 82% of BSA remained unscathed after in vitro digestion. Therefore, prilled NiMOS was shown to be a promising and flexible multi-compartment system for oral (local) macromolecular delivery.

  1. Defect-related hysteresis in nanotube-based nano-electromechanical systems

    Directory of Open Access Journals (Sweden)

    Pantelides Sokrates

    2011-01-01

    Full Text Available Abstract The electronic properties of multi-walled carbon nanotubes (MWCNTs depend on the positions of their walls with respect to neighboring shells. This fact can enable several applications of MWCNTs as nano-electromechanical systems (NEMS. In this article, we report the findings of a first-principles study on the stability and dynamics of point defects in double-walled carbon nanotubes (DWCNTs and their role in the response of the host systems under inter-tube displacement. Key defect-related effects, namely, sudden energy changes and hysteresis, are identified, and their relevance to a host of MWCNT-based NEMS is highlighted. The results also demonstrate the dependence of these effects on defect clustering and chirality of DWCNT shells.

  2. Making sense of enterprise systems in institutions

    DEFF Research Database (Denmark)

    Svejvig, Per; Jensen, Tina Blegind

    2013-01-01

    Whereas previous research provides a number of accounts of failure prone enterprise system (ES) implementations, empirical evidence of the re-implementation of an accounting system in a Scandinavian high-tech company shows how the system became highly integrated, accepted by its users, and well......-aligned to the work processes. To learn from this case study, we investigate the interactive and dynamic relationships among the enterprise system, people and institutional properties. We investigate the institutional structures and the sensemaking processes at play to identify how the idea of an efficient accounting...

  3. Humidity sensing properties of different single-walled carbon nanotube composite films fabricated by layer-by-layer self-assembly technique

    Science.gov (United States)

    Jing, Hongjun; Jiang, Yadong; Du, Xiaosong; Tai, Huiling; Xie, Guangzhong

    2012-10-01

    Poly(diallyldimethylammonium chloride)/single-walled carbon nanotube (PDDA/SWNT) multilayered thin films were prepared on quartz crystal microbalance by layer-by-layer self-assembly technique, and their sensing properties to humidity were studied. The SWNTs were characterized by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The composite films were observed by field-emission scanning electron microscope. Two types of SWNT humidity sensors were fabricated using SWNTs and carboxyl (COOH) modified SWNTs as sensitive material, respectively. The results showed that the sensitivity of the PDDA/SWNT-COOH humidity sensor was 20.23 % higher than that of the PDDA/SWNT sensor. In contrast, the latter had a much superior hysteresis property, and the reason to cause this phenomenon was discussed.

  4. Characterization of Layer-by-layer Self-assembled Multi-walled Carbon Nanotube Film Sensor and Its Ethanol Gas-sensing Properties

    Directory of Open Access Journals (Sweden)

    Bokai Xia

    2013-03-01

    Full Text Available Multi-wall carbon nanotubes (MWNTs film-based sensor on the substrate of printed circuit board (PCB with interdigital electrodes (IDE were fabricated using layer-by-layer self-assembly, and the electrical properties of MWNTs film sensor were investigated through establishing models involved with number of self-assembled layers and IDE finger gap, and also its ethanol gas-sensing properties with varying gas concentration are characterized at room temperature. Through comparing with the thermal evaporation method, the experiment results shown that the layer-by-layer self-assembled MWNTs film sensor have a faster response and more sensitive resistance change when exposed to ethanol gas, indicated a prospective application for ethanol gas detection with high performance and low-cost.

  5. The effect of carbon nanotubes on drug delivery in an electro-sensitive transdermal drug delivery system.

    Science.gov (United States)

    Im, Ji S; Bai, Byong Ch; Lee, Young-Seak

    2010-02-01

    An electro-sensitive transdermal drug delivery system was prepared by the electrospinning method to control drug release. A semi-interpenetrating polymer network was prepared as the matrix with polyethylene oxide and pentaerythritol triacrylate polymers. Multi-walled carbon nanotubes were used as an additive to increase the electrical sensitivity. The release experiment was carried out under different electric voltage conditions. Carbon nanotubes were observed in the middle of the electrospun fibers by SEM and TEM. The amount of released drug was effectively increased with higher applied electric voltages. These results were attributed to the excellent electrical conductivity of the carbon additive. The suggested mechanism of drug release involves polyethylene oxide of the semi-interpenetrating polymer network being dissolved under the effects of carbon nanotubes, thereby releasing the drug. The effects of the electro-sensitive transdermal drug delivery system were enhanced by the carbon nanotubes.

  6. Optical fiber gas sensing system based on FBG filtering

    Science.gov (United States)

    Wang, Shutao

    2008-10-01

    An optical fiber gas sensing system based on the law of Beer-Lambert is designed to determine the concentration of gas. This technique relies on the fact that the target gas has a unique, well-defined absorption characteristic within the infrared region of electromagnetic spectrum. The narrow-band filtering characteristic of optical fiber Bragg grating is used to produce the narrow spectrum light signal. An aspheric objective optical fiber collimator is used in the system as an optical fiber gas sensing detector to improve the sensitivity and stability. Experimental results show there is a high measuring sensitivity at 0.01%, and the measuring range goes beyond 5%.

  7. Multiple classifier system for remote sensing image classification: a review.

    Science.gov (United States)

    Du, Peijun; Xia, Junshi; Zhang, Wei; Tan, Kun; Liu, Yi; Liu, Sicong

    2012-01-01

    Over the last two decades, multiple classifier system (MCS) or classifier ensemble has shown great potential to improve the accuracy and reliability of remote sensing image classification. Although there are lots of literatures covering the MCS approaches, there is a lack of a comprehensive literature review which presents an overall architecture of the basic principles and trends behind the design of remote sensing classifier ensemble. Therefore, in order to give a reference point for MCS approaches, this paper attempts to explicitly review the remote sensing implementations of MCS and proposes some modified approaches. The effectiveness of existing and improved algorithms are analyzed and evaluated by multi-source remotely sensed images, including high spatial resolution image (QuickBird), hyperspectral image (OMISII) and multi-spectral image (Landsat ETM+). Experimental results demonstrate that MCS can effectively improve the accuracy and stability of remote sensing image classification, and diversity measures play an active role for the combination of multiple classifiers. Furthermore, this survey provides a roadmap to guide future research, algorithm enhancement and facilitate knowledge accumulation of MCS in remote sensing community.

  8. Multiple Classifier System for Remote Sensing Image Classification: A Review

    Directory of Open Access Journals (Sweden)

    Yi Liu

    2012-04-01

    Full Text Available Over the last two decades, multiple classifier system (MCS or classifier ensemble has shown great potential to improve the accuracy and reliability of remote sensing image classification. Although there are lots of literatures covering the MCS approaches, there is a lack of a comprehensive literature review which presents an overall architecture of the basic principles and trends behind the design of remote sensing classifier ensemble. Therefore, in order to give a reference point for MCS approaches, this paper attempts to explicitly review the remote sensing implementations of MCS and proposes some modified approaches. The effectiveness of existing and improved algorithms are analyzed and evaluated by multi-source remotely sensed images, including high spatial resolution image (QuickBird, hyperspectral image (OMISII and multi-spectral image (Landsat ETM+.Experimental results demonstrate that MCS can effectively improve the accuracy and stability of remote sensing image classification, and diversity measures play an active role for the combination of multiple classifiers. Furthermore, this survey provides a roadmap to guide future research, algorithm enhancement and facilitate knowledge accumulation of MCS in remote sensing community.

  9. Fibre Optical Radiation Sensing System for TESLA

    CERN Document Server

    Körfer, M

    2001-01-01

    High energy accelerators generate ionising radiation along the beam-line and at target places. This radiation is related to beam losses or dark currents. The in-situ measurement of this ionising dose that is distributed over long distances or large areas requires a new monitor system. This paper presents first results and the concept of such a monitor system at the Tesla Test Facility.

  10. The directed preparation of TiO2 nanotubes film on FTO substrate via hydrothermal method for gas sensing application

    Directory of Open Access Journals (Sweden)

    Pham Van Viet

    2016-04-01

    Full Text Available In this research, we directly synthesized TiO2 nanotubes film on Fluorine doped Tin oxide (FTO substrate via hydrothermal method from commercial TiO2 in NaOH solution at 135 ℃ for 24 hours. The samples were characterized by X-ray diffraction (XRD pattern, field emission scanning electron microscopy (FESEM and transmitting electron microscopy (TEM. The average diameter of TiO2 nanotubes (TNTs is about 10–12 nm and their length is about a few hundred nanometers. The sensitivity ability of TNTs increases as the gas concentration increases and developing to the highest sensitivity of TNTs is 2.4 at 700 ppm of the ethanol concentration. The same as the gas concentration, the sensitivity of TNTs increases when the temperature increases. Besides, the sensitivity of samples at 250 ℃ is doubled compared to samples determined at 100 ℃.

  11. EXPERIMENTAL STUDY OF LOAD SENSING SYSTEM WITH LONG PIPES

    Institute of Scientific and Technical Information of China (English)

    Kong Xiaowu; Qiu Minxiu; Wei Jianhua

    2005-01-01

    A test platform is established as per the practical working condition of elevating platform fire truck. The influences of pipes and load on dynamic characteristics of load-sensing system are studied by series of step response experiments. Experimental results show that the feedback pipe makes the most important influence on the dynamic response speed of load-sensing system. Its internal diameter should be optimized for given length of pipe. On the other hand, the stability of load-sensing pump is improved as the length of input pipe increases in a certain range. The influence of input pipe on the dynamic response speed is caused mainly by the pressure-wave travel time in the input pipe.

  12. Controllable synthesis of Co{sub 3}O{sub 4}/polyethyleneimine-carbon nanotubes nanocomposites for CO and NH{sub 3} gas sensing at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yufei [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080 (China); Kan, Kan [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080 (China); Institute of Advanced Technology, Heilongjiang Academy of Sciences, Harbin 150000 (China); Song, Wanzhen; Zhang, Guo; Dang, Lifang [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080 (China); Xie, Yu [Department of Materials Chemistry, Nanchang Hangkong University, Nanchang 330063 (China); Shen, Peikang [Department of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Li, Li, E-mail: llwjjhlju@sina.cn [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080 (China); Key Laboratory of Chemical Engineering Process & Technology for High-efficiency Conversion, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080 (China); Shi, Keying, E-mail: shikeying2008@163.com [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080 (China)

    2015-08-05

    Graphical abstract: Co{sub 3}O{sub 4}/polyethyleneimine-carbon nanotubes composites (CoPCNTs) have been successfully controllable synthesized via hydrothermal method at different temperature. The CoPCNTs sensors exhibited the highest response to CO and NH{sub 3} gases with response time of 4 s and 4.3 s, low detection limit of 5 ppm and 1 ppm at room temperature, respectively. The enhanced gas sensing could be ascribed to the synergistic effect between the tiny size of Co{sub 3}O{sub 4} and good conductivity of carbon nanotubes functionalized by polyethyleneimine. - Highlights: • The CNTs functionalized by polyethyleneimine provided a new functional structural. • The novel 1D structure could capture and migrate electrons quickly. • The Co{sub 3}O{sub 4} nanoparticles liked a snake winding around CNTs. • The gas sensor could work at room temperatures, which suit to practical application. - Abstract: A novel 1D Co{sub 3}O{sub 4}/polyethyleneimine-carbon nanotubes composites (CoPCNTs) have been successfully synthesized via hydrothermal method at different temperature. The CNTs functionalized by polyethyleneimine (PCNTs) provided a new material with new structural and functional properties. The PCNTs was used as loading guider and electron transfer path. The Co{sub 3}O{sub 4} nanoparticles (NPs) loaded on the PCNTs surface liked a snake winding around CNTs, and the size was about 5–10 nm. The gas sensing characteristics of the CoPCNTs sensors to carbon monoxide (CO) and ammonia (NH{sub 3}) were evaluated with different gas concentration. The CoPCNTs sensors grown at 160 °C exhibited the highest response to CO and NH{sub 3} gases with response time of 4 s and 4.3 s at room temperature (RT), respectively. Hence, the approach developed in this work would be important for the low-cost and large-scale production of the CoPCNTs materials with highly promising applications in gas sensors.

  13. Recommendation-Aware Smartphone Sensing System

    Directory of Open Access Journals (Sweden)

    Mu-Yen Chen

    2014-12-01

    Full Text Available The context-aware concept is to reduce the gap between users and information systems so that the information systems actively get to understand users’ context and demand and in return provide users with better experience. This study integrates the concept of context-aware with association algorithms to establish the context-aware recommendation systems (CARS. The CARS contains three modules and provides the product recommendations for users with their smartphone. First, the simple RSSI Indoor localization module (SRILM locates the user position and detects the context information surrounding around users. Second, the Apriori recommendation module (ARM provides effective recommended product information for users through association rules mining. The appropriate product information can be received effectiveness and greatly enhanced the recommendation service.

  14. BEMS systems give developer sixth sense.

    Science.gov (United States)

    Baillie, Jonathan

    2011-08-01

    Duty-bound under contracts with partner NHS PCTs, independent primary care contractors, and other community stakeholders who lease healthcare premises from it, to ensure that the buildings' energy systems and plant run efficiently and cost-effectively, Community Solutions, a leading investor in, and developer of, UK community-based health, social, and local authority services, is now standardising on Trend Controls' building energy management systems to ensure that such vital equipment runs within defined parameters, and that facilities without FM personnel on site day-to-day are kept both comfortable to work in, and fit-for-purpose.

  15. Development of Metal-impregnated Single Walled Carbon Nanotubes for Toxic Gas Contaminant Control in Advanced Life Support Systems

    Science.gov (United States)

    Cinke, Martin; Li, Jing; Chen, Bin; Wignarajah, Kanapathipillai; Pisharody, Suresh A.; Fisher, John W.; Delzeit, Lance; Meyyappan, Meyya; Partridge, Harry; Clark, Kimberlee

    2003-01-01

    The success of physico-chemical waste processing and resource recovery technologies for life support application depends partly on the ability of gas clean-up systems to efficiently remove trace contaminants generated during the process with minimal use of expendables. Highly purified metal-impregnated carbon nanotubes promise superior performance over conventional approaches to gas clean-up due to their ability to direct the selective uptake gaseous species based both on the nanotube s controlled pore size, high surface area, and ordered chemical structure that allows functionalization and on the nanotube s effectiveness as a catalyst support material for toxic contaminants removal. We present results on the purification of single walled carbon nanotubes (SWCNT) and efforts at metal impregnation of the SWCNT's.

  16. A Versatile Prototyping System for Capacitive Sensing

    Directory of Open Access Journals (Sweden)

    Daniel HRACH

    2008-04-01

    Full Text Available This paper presents a multi-purpose and easy to handle rapid prototyping platform that has been designed for capacitive measurement systems. The core of the prototype platform is a Digital Signal Processor board that allows for the entire data acquisition, data (pre- processing and storage, and communication with any host computer. The platform is running on uCLinux operating system and features the possibility of a fast design and evaluation of capacitive sensor developments. To show the practical benefit of the prototyping platform, three exemplary applications are presented. For all applications, the platform is just plugged to the electrode structure of the sensor front-end without the need for analogue signal pre-conditioning.

  17. Optically powered active sensing system for Internet Of Things

    Science.gov (United States)

    Gao, Chen; Wang, Jin; Yin, Long; Yang, Jing; Jiang, Jian; Wan, Hongdan

    2014-10-01

    Internet Of Things (IOT) drives a significant increase in the extent and type of sensing technology and equipment. Sensors, instrumentation, control electronics, data logging and transmission units comprising such sensing systems will all require to be powered. Conventionally, electrical powering is supplied by batteries or/and electric power cables. The power supply by batteries usually has a limited lifetime, while the electric power cables are susceptible to electromagnetic interference. In fact, the electromagnetic interference is the key issue limiting the power supply in the strong electromagnetic radiation area and other extreme environments. The novel alternative method of power supply is power over fiber (PoF) technique. As fibers are used as power supply lines instead, the delivery of the power is inherently immune to electromagnetic radiation, and avoids cumbersome shielding of power lines. Such a safer power supply mode would be a promising candidate for applications in IOT. In this work, we built up optically powered active sensing system, supplying uninterrupted power for the remote active sensors and communication modules. Also, we proposed a novel maximum power point tracking technique for photovoltaic power convertors. In our system, the actual output efficiency greater than 40% within 1W laser power. After 1km fiber transmission and opto-electric power conversion, a stable electric power of 210mW was obtained, which is sufficient for operating an active sensing system.

  18. 33 CFR 127.201 - Sensing and alarm systems.

    Science.gov (United States)

    2010-07-01

    ... (CONTINUED) WATERFRONT FACILITIES WATERFRONT FACILITIES HANDLING LIQUEFIED NATURAL GAS AND LIQUEFIED HAZARDOUS GAS Waterfront Facilities Handling Liquefied Natural Gas Equipment § 127.201 Sensing and alarm systems. (a) Fixed sensors must have audio and visual alarms in the control room and audio alarms...

  19. Advanced 3D Sensing and Visualization System for Unattended Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, J.J.; Little, C.Q.; Nelson, C.L.

    1999-01-01

    The purpose of this project was to create a reliable, 3D sensing and visualization system for unattended monitoring. The system provides benefits for several of Sandia's initiatives including nonproliferation, treaty verification, national security and critical infrastructure surety. The robust qualities of the system make it suitable for both interior and exterior monitoring applications. The 3D sensing system combines two existing sensor technologies in a new way to continuously maintain accurate 3D models of both static and dynamic components of monitored areas (e.g., portions of buildings, roads, and secured perimeters in addition to real-time estimates of the shape, location, and motion of humans and moving objects). A key strength of this system is the ability to monitor simultaneous activities on a continuous basis, such as several humans working independently within a controlled workspace, while also detecting unauthorized entry into the workspace. Data from the sensing system is used to identi~ activities or conditions that can signi~ potential surety (safety, security, and reliability) threats. The system could alert a security operator of potential threats or could be used to cue other detection, inspection or warning systems. An interactive, Web-based, 3D visualization capability was also developed using the Virtual Reality Modeling Language (VRML). The intex%ace allows remote, interactive inspection of a monitored area (via the Internet or Satellite Links) using a 3D computer model of the area that is rendered from actual sensor data.

  20. Fluorescent Sensing of Fluoride in Cellular System

    Science.gov (United States)

    Jiao, Yang; Zhu, Baocun; Chen, Jihua; Duan, Xiaohong

    2015-01-01

    Fluoride ions have the important roles in a lot of physiological activities related with biological and medical system, such as water fluoridation, caries treatment, and bone disease treatment. Great efforts have been made to develop new methods and strategies for F- detection in the past decades. Traditional methods for the detection of F- including ion chromatography, ion-selective electrodes, and spectroscopic techniques have the limitations in the biomedicine research. The fluorescent probes for F- are very promising that overcome some drawbacks of traditional fluoride detection methods. These probes exhibit high selectivity, high sensitivity as well as quick response to the detection of fluoride anions. The review commences with a brief description of photophysical mechanisms for fluorescent probes for fluoride, including photo induced electron transfer (PET), intramolecular charge transfer (ICT), fluorescence resonance energy transfer (FRET), and excited-state intramolecular proton transfer (ESIPT). Followed by a discussion about common dyes for fluorescent fluoride probes, such as anthracene, naphalimide, pyrene, BODIPY, fluorescein, rhodamine, resorufin, coumarin, cyanine, and near-infrared (NIR) dyes. We divide the fluorescent probes for fluoride in cellular application systems into nine groups, for example, type of hydrogen bonds, type of cleavage of Si-O bonds, type of Si-O bond cleavage and cylization reactions, etc. We also review the recent reported carriers in the delivery of fluorescent fluoride probes. Seventy-four typical fluorescent fluoride probes are listed and compared in detail, including quantum yield, reaction medium, excitation and emission wavelengths, linear detection range, selectivity for F-, mechanism, and analytical applications. Finally, we discuss the future challenges of the application of fluorescent fluoride probes in cellular system and in vivo. We wish that more and more excellent fluorescent fluoride probes will be developed

  1. Social sensing building reliable systems on unreliable data

    CERN Document Server

    Wang, Dong; Kaplan, Lance

    2015-01-01

    Increasingly, human beings are sensors engaging directly with the mobile Internet. Individuals can now share real-time experiences at an unprecedented scale. Social Sensing: Building Reliable Systems on Unreliable Data looks at recent advances in the emerging field of social sensing, emphasizing the key problem faced by application designers: how to extract reliable information from data collected from largely unknown and possibly unreliable sources. The book explains how a myriad of societal applications can be derived from this massive amount of data collected and shared by average individu

  2. Fabrication and Characterization of Multi-Walled Carbon Nanotube (MWCNT) and Ni-Coated Multi-Walled Carbon Nanotube (Ni-MWCNT) Repair Patches for Carbon Fiber Reinforced Composite Systems

    Science.gov (United States)

    Johnson, Brienne; Caraccio, Anne; Tate, LaNetra; Jackson, Dionne

    2011-01-01

    Multi-walled carbon nanotube (MWCNT)/epoxy and nickel-coated multi-walled carbon nanotube (Ni-MWCNT)/epoxy systems were fabricated into carbon fiber composite repair patches via vacuum resin infusion. Two 4 ply patches were manufactured with fiber orientations of [90/ 90/ 4590] and [0/90/ +45/ -45]. Prior to resin infusion, the MWCNT/Epoxy system and NiMWCNT/ epoxy systems were optimized for dispersion quality. Scanning electron microscopy (SEM) and optical microscopy (OM) were used to determine the presence ofcarbon nanotubes and assess dispersion quality. Decomposition temperatures were determined via thermogravametric analysis (TGA). SEM and TGA were also used to evaluate the composite repair patches.

  3. Acid yellow 9 as a dispersing agent for carbon nanotubes: preparation of redox polymer-carbon nanotube composite film and its sensing application towards ascorbic acid and dopamine.

    Science.gov (United States)

    Kumar, S Ashok; Wang, Sea-Fue; Yang, Thomas C-K; Yeh, Chun-Ting

    2010-08-15

    In this study, we show that acid yellow 9 (4-amino-1-1'-azobenzene-3,4'-disulfonicacid, AY) is a good stabilizing agent for multi-walled carbon nanotubes (MWCNTs). MWCNTs dispersed in AY solution was remained stable about three months and even remained stable after centrifugation at 10,000 rpm for 30 min. Using MWCNTs/AY dispersion, thin-films were prepared on indium tin oxide coated glass electrode and glassy carbon electrodes. Further, dried films of MWCNTs/AY were subjected to electropolymerization in 0.1M H(2)SO(4) solution. Adsorbed AY molecules on MWCNTs get polymerized and they yield a polymer-MWCNTs nanocomposite film on electrode surface which is found to be electrochemically active in wide pH range (1-11). Characterization studies were performed using cyclic voltammetry and SEM. These studies are supported that hybrid material PAY/MWCNTs was obtained. Moreover, newly synthesized PAY-MWCNTs composite film showed excellent electrocatalytic activity towards oxidation of dopamine (DA) and ascorbic acid (AA) with high sensitivity in physiological pH. Linear sweep voltammetry was employed to the determination of DA in the presence of AA in the range of 2x10(-7) to 1.4x10(-6) M. Amperometry was employed to determination of AA at 0.0 V in the range from 1x10(-6) to 5.6x10(-5) M, and DA, uric acid are not interfered on the steady-state current of AA. In addition, real samples such as dopamine injection and AA spiked into human urine were analyzed using PAY/MWCNTs composite modified electrode and satisfactory results were obtained.

  4. Intelligent Vision System for Door Sensing Mobile Robot

    Directory of Open Access Journals (Sweden)

    Jharna Majumdar

    2012-08-01

    Full Text Available Wheeled Mobile Robots find numerous applications in the Indoor man made structured environments. In order to operate effectively, the robots must be capable of sensing its surroundings. Computer Vision is one of the prime research areas directed towards achieving these sensing capabilities. In this paper, we present a Door Sensing Mobile Robot capable of navigating in the indoor environment. A robust and inexpensive approach for recognition and classification of the door, based on monocular vision system helps the mobile robot in decision making. To prove the efficacy of the algorithm we have designed and developed a ‘Differentially’ Driven Mobile Robot. A wall following behavior using Ultra Sonic range sensors is employed by the mobile robot for navigation in the corridors.  Field Programmable Gate Arrays (FPGA have been used for the implementation of PD Controller for wall following and PID Controller to control the speed of the Geared DC Motor.

  5. A Tunable Carbon Nanotube Oscillator

    Science.gov (United States)

    Sazonova, Vera

    2005-03-01

    Nanoelectromechanical systems (NEMS) hold promise for a number of scientific and technological applications. Carbon nanotubes (NT) are perhaps the ultimate material for realizing a NEMS device as they are the stiffest material known, have low density, ultrasmall cross sections and can be defect-free. Equally important, a nanotube can act as a transistor and thus is able to sense its own motion. Here, we report the electrical actuation and detection of the guitar-string oscillation modes of doubly-clamped NT oscillators. We observed resonance frequencies in the 5MHz to 150MHz range with quality factors in the 50 to 100 range. We showed that the resonance frequencies can be widely tuned by a gate voltage. We also report on the temperature dependence of the quality factor and present a discussion of possible loss mechanisms.

  6. Intelligent fiber sensing system for the oil field area

    Science.gov (United States)

    Sun, Wenju; Ma, Linping

    2010-08-01

    Optical Fiber strain sensor using fiber Bragg grating are poised to play a major role in structural health from military to civil engineering. Fiber Bragg Grating sensor is a practical type of fiber optic sensors. Its measurement is encoded with the wavelength of the optical signal reflected from fiber Bragg grating. The method of measuring the absolute optical wavelength is a critical component of the fiber optic sensing system. To reliably detect very small changes in the environment at the sensor, the interrogation system must provide accurate and repeatable wavelength measurements. Energy sources are increasingly scarce in the world. Getting oil from the oil-wells has become more and more difficult. Therefore, new technology to monitor the oil-well condition has become extremely important. The traditional electrical sensor system is no longer useful because of the down-hole's high temperature and high pressure environment. The optical fiber sensing system is the first choice to monitor this condition. This system will reduce the cost and increase the productivity. In the high pressure and high temperature environment, the traditional packed fiber grating pressure-temperature sensor will be no longer reliability. We have to find a new fiber grating temperature-pressure sensor element and the interrogation system. In this work we use the very narrow bandwidth birefringent fiber grating as the sensing element. We obtain the interrogation system has 0.1 pm resolution.

  7. [Remote passive sensing of aeroengine exhausts using FTIR system].

    Science.gov (United States)

    Xia, Qing; Zuo, Hong-Fu; Li, Shao-Cheng; Wen, Zhen-Hua; Li, Yao-Hua

    2009-03-01

    The traditional method of measuring the aeroengine exhausts is intrusive gas sampling analysis techniques. The disadvantages of the techniques include complex system, difficult operation, high costs and potential danger because of back-pressure effects. The non-intrusive methods have the potential to overcome these problems. So the remote FTIR passive sensing is applied to monitor aeroengine exhausts and determine the concentration of the exhausts gases of aeroengines. The principle of FTIR remote passive sensing is discussed. The model algorithm for the calibration of FTIR system, the radiance power distribution and gas concentration are introduced. TENSOR27 FTIR-system was used to measure the spectra of infrared radiation emitted by the hot gases of exhausts in a test rig. The emission spectra of exhausts were obtained under different thrusts. By analyzing the spectra, the concentrations of CO2, CO and NO concentration were calculated under 4 thrusts. Researches on the determination of concentration of the exhausts gases of aeroengines by using the remote FTIR sensing are still in early stage in the domestic aeronautics field. The results of the spectra and concentration in the aeroengine test are published for the first time. It is shown that the remote FTIR passive sensing techniques have a great future in monitoring the hot gas of the aeroengines exhausts.

  8. Adaptive Sensing Based on Profiles for Sensor Systems

    Directory of Open Access Journals (Sweden)

    Yoshiteru Ishida

    2009-10-01

    Full Text Available 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.

  9. Predicting catastrophes in nonlinear dynamical systems by compressive sensing.

    Science.gov (United States)

    Wang, Wen-Xu; Yang, Rui; Lai, Ying-Cheng; Kovanis, Vassilios; Grebogi, Celso

    2011-04-15

    An extremely challenging problem of significant interest is to predict catastrophes in advance of their occurrences. We present a general approach to predicting catastrophes in nonlinear dynamical systems under the assumption that the system equations are completely unknown and only time series reflecting the evolution of the dynamical variables of the system are available. Our idea is to expand the vector field or map of the underlying system into a suitable function series and then to use the compressive-sensing technique to accurately estimate the various terms in the expansion. Examples using paradigmatic chaotic systems are provided to demonstrate our idea.

  10. Predicting catastrophes in nonlinear dynamical systems by compressive sensing

    CERN Document Server

    Wang, Wen-Xu; Lai, Ying-Cheng; Kovanis, Vassilios; Grebogi, Celso

    2011-01-01

    An extremely challenging problem of significant interest is to predict catastrophes in advance of their occurrences. We present a general approach to predicting catastrophes in nonlinear dynamical systems under the assumption that the system equations are completely unknown and only time series reflecting the evolution of the dynamical variables of the system are available. Our idea is to expand the vector field or map of the underlying system into a suitable function series and then to use the compressive-sensing technique to accurately estimate the various terms in the expansion. Examples using paradigmatic chaotic systems are provided to demonstrate our idea.

  11. Sensory systems II senses other than vision

    CERN Document Server

    Wolfe, Jeremy M

    1988-01-01

    This series of books, "Readings from the Encyclopedia of Neuroscience." consists of collections of subject-clustered articles taken from the Encyclopedia of Neuroscience. The Encyclopedia of Neuroscience is a reference source and compendium of more than 700 articles written by world authorities and covering all of neuroscience. We define neuroscience broadly as including all those fields that have as a primary goal the under­ standing of how the brain and nervous system work to mediate/control behavior, including the mental behavior of humans. Those interested in specific aspects of the neurosciences, particular subject areas or specialties, can of course browse through the alphabetically arranged articles of the En­ cyclopedia or use its index to find the topics they wish to read. However. for those readers-students, specialists, or others-who will find it useful to have collections of subject-clustered articles from the Encyclopedia, we issue this series of "Readings" in paperback. Students in neuroscienc...

  12. Hybrid architecture active wavefront sensing and control system, and method

    Science.gov (United States)

    Feinberg, Lee D. (Inventor); Dean, Bruce H. (Inventor); Hyde, Tristram T. (Inventor)

    2011-01-01

    According to various embodiments, provided herein is an optical system and method that can be configured to perform image analysis. The optical system can comprise a telescope assembly and one or more hybrid instruments. The one or more hybrid instruments can be configured to receive image data from the telescope assembly and perform a fine guidance operation and a wavefront sensing operation, simultaneously, on the image data received from the telescope assembly.

  13. Noncovalent Protein and Peptide Functionalization of Single-Walled Carbon Nanotubes for Biodelivery and Optical Sensing Applications.

    Science.gov (United States)

    Antonucci, Alessandra; Kupis-Rozmysłowicz, Justyna; Boghossian, Ardemis A

    2017-04-05

    The exquisite structural and optical characteristics of single-walled carbon nanotubes (SWCNTs), combined with the tunable specificities of proteins and peptides, can be exploited to strongly benefit technologies with applications in fields ranging from biomedicine to industrial biocatalysis. The key to exploiting the synergism of these materials is designing protein/peptide-SWCNT conjugation schemes that preserve biomolecule activity while keeping the near-infrared optical and electronic properties of SWCNTs intact. Since sp(2) bond-breaking disrupts the optoelectronic properties of SWCNTs, noncovalent conjugation strategies are needed to interface biomolecules to the nanotube surface for optical biosensing and delivery applications. An underlying understanding of the forces contributing to protein and peptide interaction with the nanotube is thus necessary to identify the appropriate conjugation design rules for specific applications. This article explores the molecular interactions that govern the adsorption of peptides and proteins on SWCNT surfaces, elucidating contributions from individual amino acids as well as secondary and tertiary protein structure and conformation. Various noncovalent conjugation strategies for immobilizing peptides, homopolypeptides, and soluble and membrane proteins on SWCNT surfaces are presented, highlighting studies focused on developing near-infrared optical sensors and molecular scaffolds for self-assembly and biochemical analysis. The analysis presented herein suggests that though direct adsorption of proteins and peptides onto SWCNTs can be principally applied to drug and gene delivery, in vivo imaging and targeting, or cancer therapy, nondirect conjugation strategies using artificial or natural membranes, polymers, or linker molecules are often better suited for biosensing applications that require conservation of biomolecular functionality or precise control of the biomolecule's orientation. These design rules are intended to

  14. Efficient Lossy Compression for Compressive Sensing Acquisition of Images in Compressive Sensing Imaging Systems

    Directory of Open Access Journals (Sweden)

    Xiangwei Li

    2014-12-01

    Full Text Available Compressive Sensing Imaging (CSI is a new framework for image acquisition, which enables the simultaneous acquisition and compression of a scene. Since the characteristics of Compressive Sensing (CS acquisition are very different from traditional image acquisition, the general image compression solution may not work well. In this paper, we propose an efficient lossy compression solution for CS acquisition of images by considering the distinctive features of the CSI. First, we design an adaptive compressive sensing acquisition method for images according to the sampling rate, which could achieve better CS reconstruction quality for the acquired image. Second, we develop a universal quantization for the obtained CS measurements from CS acquisition without knowing any a priori information about the captured image. Finally, we apply these two methods in the CSI system for efficient lossy compression of CS acquisition. Simulation results demonstrate that the proposed solution improves the rate-distortion performance by 0.4~2 dB comparing with current state-of-the-art, while maintaining a low computational complexity.

  15. Efficient lossy compression for compressive sensing acquisition of images in compressive sensing imaging systems.

    Science.gov (United States)

    Li, Xiangwei; Lan, Xuguang; Yang, Meng; Xue, Jianru; Zheng, Nanning

    2014-12-05

    Compressive Sensing Imaging (CSI) is a new framework for image acquisition, which enables the simultaneous acquisition and compression of a scene. Since the characteristics of Compressive Sensing (CS) acquisition are very different from traditional image acquisition, the general image compression solution may not work well. In this paper, we propose an efficient lossy compression solution for CS acquisition of images by considering the distinctive features of the CSI. First, we design an adaptive compressive sensing acquisition method for images according to the sampling rate, which could achieve better CS reconstruction quality for the acquired image. Second, we develop a universal quantization for the obtained CS measurements from CS acquisition without knowing any a priori information about the captured image. Finally, we apply these two methods in the CSI system for efficient lossy compression of CS acquisition. Simulation results demonstrate that the proposed solution improves the rate-distortion performance by 0.4~2 dB comparing with current state-of-the-art, while maintaining a low computational complexity.

  16. Unmanned aerial systems for photogrammetry and remote sensing: A review

    Science.gov (United States)

    Colomina, I.; Molina, P.

    2014-06-01

    We discuss the evolution and state-of-the-art of the use of Unmanned Aerial Systems (UAS) in the field of Photogrammetry and Remote Sensing (PaRS). UAS, Remotely-Piloted Aerial Systems, Unmanned Aerial Vehicles or simply, drones are a hot topic comprising a diverse array of aspects including technology, privacy rights, safety and regulations, and even war and peace. Modern photogrammetry and remote sensing identified the potential of UAS-sourced imagery more than thirty years ago. In the last five years, these two sister disciplines have developed technology and methods that challenge the current aeronautical regulatory framework and their own traditional acquisition and processing methods. Navety and ingenuity have combined off-the-shelf, low-cost equipment with sophisticated computer vision, robotics and geomatic engineering. The results are cm-level resolution and accuracy products that can be generated even with cameras costing a few-hundred euros. In this review article, following a brief historic background and regulatory status analysis, we review the recent unmanned aircraft, sensing, navigation, orientation and general data processing developments for UAS photogrammetry and remote sensing with emphasis on the nano-micro-mini UAS segment.

  17. Plant health sensing system for determining nitrogen status in plants

    Science.gov (United States)

    Thomasson, J. A.; Sui, Ruixiu; Read, John J.; Reddy, K. R.

    2004-03-01

    A plant health sensing system was developed for determining nitrogen status in plants. The system consists of a multi-spectral optical sensor and a data-acquisition and processing unit. The optical sensor"s light source provides modulated panchromatic illumination of a plant canopy with light-emitting diodes, and the sensor measures spectral reflectance through optical filters that partition the energy into blue, green, red, and near-infrared wavebands. Spectral reflectance of plants is detected in situ, at the four wavebands, in real time. The data-acquisition and processing unit is based on a single board computer that collects data from the multi-spectral sensor and spatial information from a global positioning system receiver. Spectral reflectance at the selected wavebands is analyzed, with algorithms developed during preliminary work, to determine nitrogen status in plants. The plant health sensing system has been tested primarily in the laboratory and field so far, and promising results have been obtained. This article describes the development, theory of operation, and test results of the plant health sensing system.

  18. Wireless and Powerless Sensing Node System Developed for Monitoring Motors

    Directory of Open Access Journals (Sweden)

    Dasheng Lee

    2008-08-01

    Full Text Available Reliability and maintainability of tooling systems can be improved through condition monitoring of motors. However, it is difficult to deploy sensor nodes due to the harsh environment of industrial plants. Sensor cables are easily damaged, which renders the monitoring system deployed to assure the machine’s reliability itself unreliable. A wireless and powerless sensing node integrated with a MEMS (Micro Electro-Mechanical System sensor, a signal processor, a communication module, and a self-powered generator was developed in this study for implementation of an easily mounted network sensor for monitoring motors. A specially designed communication module transmits a sequence of electromagnetic (EM pulses in response to the sensor signals. The EM pulses can penetrate through the machine’s metal case and delivers signals from the sensor inside the motor to the external data acquisition center. By using induction power, which is generated by the motor’s shaft rotation, the sensor node is self-sustaining; therefore, no power line is required. A monitoring system, equipped with novel sensing nodes, was constructed to test its performance. The test results illustrate that, the novel sensing node developed in this study can effectively enhance the reliability of the motor monitoring system and it is expected to be a valuable technology, which will be available to the plant for implementation in a reliable motor management program.

  19. Mechanics of localized slippage in tactile sensing and application to soft sensing systems

    CERN Document Server

    Ho, Anh-Van

    2014-01-01

    Localized slippage occurs during any relative sliding of soft contacts, ranging from human fingertips to robotic fingertips. Although this phenomenon is dominant for a very short time prior to gross slippage, localized slippage is a crucial factor for any to-be-developed soft sensing system to respond to slippage before it occurs. The content of this book addresses all aspects of localized slippage, including modeling and simulating it, as well as applying it to the construction of novel sensors with slip tactile perception.

  20. Mixing height determination using remote sensing systems. General remarks

    Energy Technology Data Exchange (ETDEWEB)

    Beyrich, F. [BTU Cottbus, LS Umweltmeteorologie, Cottbus (Germany)

    1997-10-01

    Remote sensing systems can be considered today as a real alternative to classical soundings with respect to the MH (mixing height) determination. They have the basic advantage to allow continuous monitoring of the ABL (atmospheric boundary layer). Some technical issues which limit their operational use at present should be solved in the near future (frequency allocation, eye safety, costs). Taking into account specific operating conditions and the formulated-above requirements of a sounding system to be used for MH determination it becomes obvious that none of the available systems meets all of them, i.e., the `Mixing height-meter` does not exist. Therefore, reliable MH determination under a wide variety of conditions can be achieved only by integrating different instruments into a complex sounding system. The S-profiles provide a suitable data base for MH estimation from all types of remote sensing instruments. The criteria to deduce MH-values from these profiles should consider the structure type and the evolution stage of the ABL as well as the shape of the profiles. A certain kind of harmonization concerning these criteria should be achieved. MH values derived automatically from remote sensing data appear to be not yet reliable enough for direct operational use, they should be in any case critically examined by a trained analyst. Contemporary mathematical methods (wavelet transforms, fuzzy logics) are supposed to allow considerable progress in this field in the near future. (au) 19 refs.

  1. Systems analysis of carbon nanotubes: opportunities and challenges for space applications

    Science.gov (United States)

    Samareh, Jamshid A.; Siochi, Emilie J.

    2017-09-01

    Recent availability of carbon nanotubes (CNTs) in quantities and formats amenable to producing macroscale components invites consideration of these materials in space applications where their attractive properties can enable the realization of bold concepts for affordable space exploration. The challenge is to identify relevant systems and quantify the benefits at the systems level. Before significant investment or adoption of CNTs for large aerospace systems can be justified, there must be a plausible path to attain the perceived systems level benefits. This challenging step requires a close collaboration among experts on CNTs and aerospace system communities. This paper provides an overview of a few relevant potential CNTs applications for space systems and the gap that must be overcome for deployment of CNTs. It also provides a simple engineering-level systems analysis approach to quantify the benefits of using CNTs over state of the art material solutions.

  2. Research on Key Technology of Mining Remote Sensing Dynamic Monitoring Information System

    Science.gov (United States)

    Sun, J.; Xiang, H.

    2017-09-01

    Problems exist in remote sensing dynamic monitoring of mining are expounded, general idea of building remote sensing dynamic monitoring information system is presented, and timely release of service-oriented remote sensing monitoring results is established. Mobile device-based data verification subsystem is developed using mobile GIS, remote sensing dynamic monitoring information system of mining is constructed, and "timely release, fast handling and timely feedback" rapid response mechanism of remote sensing dynamic monitoring is implemented.

  3. Current development of UAV sense and avoid system

    Science.gov (United States)

    Zhahir, A.; Razali, A.; Mohd Ajir, M. R.

    2016-10-01

    As unmanned aerial vehicles (UAVs) are now gaining high interests from civil and commercialised market, the automatic sense and avoid (SAA) system is currently one of the essential features in research spotlight of UAV. Several sensor types employed in current SAA research and technology of sensor fusion that offers a great opportunity in improving detection and tracking system are presented here. The purpose of this paper is to provide an overview of SAA system development in general, as well as the current challenges facing UAV researchers and designers.

  4. Quantum Sensing of Noisy and Complex Systems under Dynamical Control

    Directory of Open Access Journals (Sweden)

    Gershon Kurizki

    2016-12-01

    Full Text Available We review our unified optimized approach to the dynamical control of quantum-probe interactions with noisy and complex systems viewed as thermal baths. We show that this control, in conjunction with tools of quantum estimation theory, may be used for inferring the spectral and spatial characteristics of such baths with high precision. This approach constitutes a new avenue in quantum sensing, dubbed quantum noise spectroscopy.

  5. Electrochemical sensing platform based on the highly ordered mesoporous carbon-fullerene system.

    Science.gov (United States)

    Zhou, Ming; Guo, Jidong; Guo, Li-ping; Bai, Jing

    2008-06-15

    In this paper, we report a novel all-carbon two-dimensionally ordered nanocomposite electrode system on the basis of the consideration of host-guest chemistry, which utilizes synergistic interactions between a nanostructured matrix of ordered mesoporous carbon (OMC) and an excellent electron acceptor of nanosized fullerene (C 60) to facilitate heterogeneous electron-transfer processes. The integration of OMC-C 60 by covalent interaction, especially its electrochemical applications for electrocatalysis, has not been explored thus far. Such integration may even appear to be counterintuitive because OMC and C 60 provide opposite electrochemical benefits in terms of facilitating heterogeneous electron-transfer processes. Nevertheless, the present work demonstrates the integration of OMC and C 60 can provide a remarkable synergistic augmentation of the current. To illuminate the concept, eight kinds of inorganic and organic electroactive compounds were employed to study the electrochemical response at an OMC-C 60 modified glassy carbon (OMC-C 60/GC) electrode for the first time, which shows more favorable electron-transfer kinetics than OMC/GC, carbon nanotube modified GC, C 60/GC, and GC electrodes. Such electrocatalytic behavior at OMC-C 60/GC electrode could be attributed to the unique physicochemical properties of OMC and C 60, especially the unusual host-guest synergy of OMC-C 60, which induced a substantial decrease in the overvoltage for NADH oxidation compared with GC electrode. The ability of OMC-C 60 to promote electron transfer not only suggests a new platform for the development of dehydrogenase-based bioelectrochemical devices but also indicates a potential of OMC-C 60 to be of a wide range of sensing applications because the electrocatalysis of different electroactive compounds at the OMC-C 60/GC electrode in this work should be a good model for constructing a novel and promising electrochemical sensing platform for further electrochemical detection of

  6. Stokes-Mueller matrix polarimetry system for glucose sensing

    Science.gov (United States)

    Phan, Quoc-Hung; Lo, Yu-Lung

    2017-05-01

    A Stokes-Mueller matrix polarimetry system consisting of a polarization scanning generator (PSG) and a high-accuracy Stokes polarimeter is used to sense the glucose concentration in aqueous solutions with and without scattering effects, respectively. In the proposed system, an electro-optic (EO) modulator driven by a saw-tooth waveform voltage is used to perform full state of polarization (linear/circular) scanning, while a self-built Stokes polarimeter is used to obtain dynamic measurements of the output polarized light intensity. It is shown that the measured output Stokes vectors have an accuracy of 10-4, i.e., one order higher than that of existing commercial Stokes polarimeters. The experimental results show that the optical rotation angle varies linearly with the glucose concentration over the range of 0-0.5 g/dl. Moreover, glucose sensing is successfully achieved at concentrations as low as 0.02 g/dl with a resolution of 10-6 deg/mm and an average deviation of 10-4 deg. In general, the polarimetry system proposed in this study provides a fast and reliable method for measuring the Stokes vectors, and thus has significant potential for biological sensing applications.

  7. 3D temperature field reconstruction using ultrasound sensing system

    Science.gov (United States)

    Liu, Yuqian; Ma, Tong; Cao, Chengyu; Wang, Xingwei

    2016-04-01

    3D temperature field reconstruction is of practical interest to the power, transportation and aviation industries and it also opens up opportunities for real time control or optimization of high temperature fluid or combustion process. In our paper, a new distributed optical fiber sensing system consisting of a series of elements will be used to generate and receive acoustic signals. This system is the first active temperature field sensing system that features the advantages of the optical fiber sensors (distributed sensing capability) and the acoustic sensors (non-contact measurement). Signals along multiple paths will be measured simultaneously enabled by a code division multiple access (CDMA) technique. Then a proposed Gaussian Radial Basis Functions (GRBF)-based approach can approximate the temperature field as a finite summation of space-dependent basis functions and time-dependent coefficients. The travel time of the acoustic signals depends on the temperature of the media. On this basis, the Gaussian functions are integrated along a number of paths which are determined by the number and distribution of sensors. The inversion problem to estimate the unknown parameters of the Gaussian functions can be solved with the measured times-of-flight (ToF) of acoustic waves and the length of propagation paths using the recursive least square method (RLS). The simulation results show an approximation error less than 2% in 2D and 5% in 3D respectively. It demonstrates the availability and efficiency of our proposed 3D temperature field reconstruction mechanism.

  8. Ammonia sensing system based on wavelength modulation spectroscopy

    Science.gov (United States)

    Viveiros, Duarte; Ferreira, João; Silva, Susana O.; Ribeiro, Joana; Flores, Deolinda; Santos, José L.; Frazão, Orlando; Baptista, José M.

    2015-06-01

    A sensing system in the near infrared region has been developed for ammonia sensing based on the wavelength modulation spectroscopy (WMS) principle. The WMS is a rather sensitive technique for detecting atomic/molecular species, presenting the advantage that it can be used in the near-infrared region by using the optical telecommunications technology. In this technique, the laser wavelength and intensity were modulated by applying a sine wave signal through the injection current, which allowed the shift of the detection bandwidth to higher frequencies where laser intensity noise was typically lower. Two multi-pass cells based on free space light propagation with 160 cm and 16 cm of optical path length were used, allowing the redundancy operation and technology validation. This system used a diode laser with an emission wavelength at 1512.21 nm, where NH3 has a strong absorption line. The control of the NH3 gas sensing system, as well as acquisition, processing and data presentation was performed.

  9. Wireless sensor systems for sense/decide/act/communicate.

    Energy Technology Data Exchange (ETDEWEB)

    Berry, Nina M.; Cushner, Adam; Baker, James A.; Davis, Jesse Zehring; Stark, Douglas P.; Ko, Teresa H.; Kyker, Ronald D.; Stinnett, Regan White; Pate, Ronald C.; Van Dyke, Colin; Kyckelhahn, Brian

    2003-12-01

    After 9/11, the United States (U.S.) was suddenly pushed into challenging situations they could no longer ignore as simple spectators. The War on Terrorism (WoT) was suddenly ignited and no one knows when this war will end. While the government is exploring many existing and potential technologies, the area of wireless Sensor networks (WSN) has emerged as a foundation for establish future national security. Unlike other technologies, WSN could provide virtual presence capabilities needed for precision awareness and response in military, intelligence, and homeland security applications. The Advance Concept Group (ACG) vision of Sense/Decide/Act/Communicate (SDAC) sensor system is an instantiation of the WSN concept that takes a 'systems of systems' view. Each sensing nodes will exhibit the ability to: Sense the environment around them, Decide as a collective what the situation of their environment is, Act in an intelligent and coordinated manner in response to this situational determination, and Communicate their actions amongst each other and to a human command. This LDRD report provides a review of the research and development done to bring the SDAC vision closer to reality.

  10. Electrochemical sensing of DNA immobilization and hybridization based on carbon nanotubes/nano zinc oxide/chitosan composite film

    Institute of Scientific and Technical Information of China (English)

    Wei Zhang; Tao Yang; Da Ming Huang; Kui Jiao

    2008-01-01

    A novel electrochemical DNA biosensor based on zinc oxide (ZnO) nanoparticles and multi-walled carbon nanotubes (MWNTs)for DNA immobilization and enhanced hybridization detection is presented. The MWNTs/nano ZnO/chitosan composite filmmodified glassy carbon electrode (MWNTs/ZnO/CHIT/GCE) was fabricated and DNA probes were immobilized on the electrodesurface. The hybridization events were monitored by differential pulse voltammetry (DPV) using methylene blue (MB) as anindicator. The sensor can effectively discriminate different DNA sequences related to PAT gene in the.transgenic corn, with adetection limit of 2.8×10-12 mol/L of target sequence.2008 Kui Jiao. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

  11. The Use of Multi-Walled Carbon Nanotubes as Possible Carrier in Drug Delivery System for Aspirin

    Science.gov (United States)

    Yusof, Alias Mohd.; Buang, Nor Aziah; Yean, Lee Sze; Ibrahim, Mohd. Lokman

    2009-06-01

    Carbon nanotubes (CNTs) have raised great interest in a number of applications, including field emission, energy storage, molecular electronics, sensors, biochips and drug delivery systems. This is due to their remarkable mechanical properties, chemical stability and biofunctionalizability. This nanomaterial is low in weight, has high strength and a high aspect ratio (long length compared to a small diameter). This paper will present a brief overview of drugs adsorbed onto the surface of carbon nanotubes via sonication method. The surface area of carbon nanotubes was measured by methylene blue method, Carbon nanotubes synthesized by catalytic chemical vapor deposition (CCVD) method were purified and functionalized in a mixture of concentrated acids (H2SO4:HNO3 = 3:1) at room temperature (25° C) via sonication in water bath, yielding carboxylic acid group on the CNTs' surface. CNT was successfully loaded with 48 %(w/w) aspirin molecules by suspending CNTs in a solution of aspirin in alcohol. Analysis of loaded CNTs by Field Emission-Scanning Electron Microscope (FESEM), Fourier Transform Infrared Spectrum (FITR) and UV-visible Spectroscopy confirmed the loading of the drug onto the CNTs. The work presented is a prelude to the direction of using carbon nanotubes as a drug delivery system to desired sites in human body.

  12. Inhibition of Lux quorum-sensing system by synthetic N-acyl-L-homoserine lactone analogous

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In the present study, we investigated the inhibition of the Lux quorum-sensing system by N-acyi cyclopentylamine (Cn-CPA). The Lux quorum-sensing system regulates luminescence gene expression in Vibriofischeri. We have already reported on the synthesis of Cn-CPA and their abilities as inhibitors of the quorum-sensing systems in Pseudomonas aeruginosa and Serratia marcescens. In the case of Pseudomonas aeruginosa (Las and Rhl quorum-sensing system) and Serratia marcescens (Spn quorum-sensing system), specific Cn-CPA with a particular acyi chain length showed the strongest inhibitory effect. In the case of the Lux quorum-sensing system, it was found that several kinds of Cn-CPA with a range from C5 to C10 showed similar strong inhibitory effects. Moreover, the inhibitory effect of Cn-CPA on the Lux quorum-sensing system was stronger than that of halogenated furanone, a natural quorum-sensing inhibitor.

  13. Inhibition of Lux quorum-sensing system by synthetic N-acyl-L-homoserine lactone analogous.

    Science.gov (United States)

    Wang, Wenzhao; Morohoshi, Tomohiro; Ikeda, Tsukasa; Chen, Liang

    2008-12-01

    In the present study, we investigated the inhibition of the Lux quorum-sensing system by N-acyl cyclopentylamine (Cn-CPA). The Lux quorum-sensing system regulates luminescence gene expression in Vibrio fischeri. We have already reported on the synthesis of Cn-CPA and their abilities as inhibitors of the quorum-sensing systems in Pseudomonas aeruginosa and Serratia marcescens. In the case of Pseudomonas aeruginosa (Las and Rhl quorum-sensing system) and Serratia marcescens (Spn quorum-sensing system), specific Cn-CPA with a particular acyl chain length showed the strongest inhibitory effect. In the case of the Lux quorum-sensing system, it was found that several kinds of Cn-CPA with a range from C5 to C10 showed similar strong inhibitory effects. Moreover, the inhibitory effect of Cn-CPA on the Lux quorum-sensing system was stronger than that of halogenated furanone, a natural quorum-sensing inhibitor.

  14. The sense of smell in systemic lupus erythematosus.

    Science.gov (United States)

    Shoenfeld, Netta; Agmon-Levin, Nancy; Flitman-Katzevman, Iveta; Paran, Daphna; Katz, Bat-sheva Porat; Kivity, Shaye; Langevitz, Pnina; Zandman-Goddard, Gisele; Shoenfeld, Yehuda

    2009-05-01

    To assess the olfactory functions in systemic lupus erythematosus (SLE) patients compared with age- and sex-matched healthy controls, and to examine the association between the sense of smell and disease activity and central nervous system (CNS) involvement. Olfactory functions in 50 SLE patients and 50 age- and sex-matched controls were evaluated using the Sniffin' Sticks test, the 3 stages of which are threshold, discrimination, and identification (TDI) of different odors. TDI scores were analyzed according to SLE disease activity and CNS involvement. In both the SLE and control groups, smell deficit correlated with male sex and older age. A decrease in the sense of smell was observed in SLE patients (46%) and controls (25%) (Psmell (anosmia) was documented only in SLE patients (10%). Total TDI scores and individual stages of smell correlated with SLE Disease Activity Index (Psmell in SLE patients compared with healthy subjects and that the decrease in the sense of smell among SLE patients correlates with disease activity and CNS involvement.

  15. Properties of polypyrrole polyvinilsulfate films for dual actuator sensing systems

    Science.gov (United States)

    Pascual, Victor H.; Otero, Toribio F.; Schumacher, Johanna

    2017-04-01

    One of the challenges of modern science is the development of actuators able to sense working conditions while actuation, mimicking the way in which biological organs work. Actuation of those organs includes nervous (electric) pulses dense reactive gels, chemical reactions exchange of ions and solvent. For that purpose, conducting polymers are being widely studied. In this work the properties of self-supported films of the polypyrrole:polyvinilsulfate (PPy/PVS) blend polymer were assessed. X-ray photoelectron spectroscopy (XPS) studies show how during reduction / oxidation the polymer exchanges cations when immersed in a NaClO4 aqueous solution, revealing free positive charges in the electrolytic solution as the driving agents leading to the swelling/shrinking of the polymer. Eventually it is the phenomenon responsible of the actuation of the polymeric motors. Submitting the system to consecutive potential sweeps shows the reaction is really sensing the scan rate used in each cycle revealing that while actuating the system is actually sensing the electrochemical working conditions.

  16. Tribotronic Transistor Array as an Active Tactile Sensing System.

    Science.gov (United States)

    Yang, Zhi Wei; Pang, Yaokun; Zhang, Limin; Lu, Cunxin; Chen, Jian; Zhou, Tao; Zhang, Chi; Wang, Zhong Lin

    2016-12-27

    Large-scale tactile sensor arrays are of great importance in flexible electronics, human-robot interaction, and medical monitoring. In this paper, a flexible 10 × 10 tribotronic transistor array (TTA) is developed as an active tactile sensing system by incorporating field-effect transistor units and triboelectric nanogenerators into a polyimide substrate. The drain-source current of each tribotronic transistor can be individually modulated by the corresponding external contact, which has induced a local electrostatic potential to act as the conventional gate voltage. By scaling down the pixel size from 5 × 5 to 0.5 × 0.5 mm(2), the sensitivities of single pixels are systematically investigated. The pixels of the TTA show excellent durability, independence, and synchronicity, which are suitable for applications in real-time tactile sensing, motion monitoring, and spatial mapping. The integrated tribotronics provides an unconventional route to realize an active tactile sensing system, with prospective applications in wearable electronics, human-machine interfaces, fingerprint identification, and so on.

  17. Sensing delamination in epoxy encapsulant systems with fiber Bragg gratings

    Science.gov (United States)

    Jones, Brad H.; Rohr, Garth D.; Kaczmarowski, Amy K.

    2016-05-01

    Fiber Bragg gratings (FBGs) are well-suited for embedded sensing of interfacial phenomena in materials systems, due to the sensitivity of their spectral response to locally non-uniform strain fields. Over the last 15 years, FBGs have been successfully employed to sense delamination at interfaces, with a clear emphasis on planar events induced by transverse cracks in fiber-reinforced plastic laminates. We have built upon this work by utilizing FBGs to detect circular delamination events at the interface between epoxy films and alumina substrates. Two different delamination processes are examined, based on stress relief induced by indentation of the epoxy film or by cooling to low temperature. We have characterized the spectral response pre- and post-delamination for both simple and chirped FBGs as a function of delamination size. We show that delamination is readily detected by the evolution of a non-uniform strain distribution along the fiber axis that persists after the stressing condition is removed. These residual strain distributions differ substantially between the delamination processes, with indentation and cooling producing predominantly tensile and compressive strain, respectively, that are well-captured by Gaussian profiles. More importantly, we observe a strong correlation between spectrally-derived measurements, such as spectral widths, and delamination size. Our results further highlight the unique capabilities of FBGs as diagnostic tools for sensing delamination in materials systems.

  18. Microbial Nucleic Acid Sensing in Oral and Systemic Diseases.

    Science.gov (United States)

    Crump, K E; Sahingur, S E

    2016-01-01

    One challenge in studying chronic infectious and inflammatory disorders is understanding how host pattern recognition receptors (PRRs), specifically toll-like receptors (TLRs), sense and respond to pathogen- or damage-associated molecular patterns, their communication with each other and different components of the immune system, and their role in propagating inflammatory stages of disease. The discovery of innate immune activation through nucleic acid recognition by intracellular PRRs such as endosomal TLRs (TLR3, TLR7, TLR8, and TLR9) and cytoplasmic proteins (absent in melanoma 2 and DNA-dependent activator of interferon regulatory factor) opened a new paradigm: Nucleic acid sensing is now implicated in multiple immune and inflammatory conditions (e.g., atherosclerosis, cancer), viral (e.g., human papillomavirus, herpes virus) and bacterial (e.g., Helicobacter pylori, pneumonia) diseases, and autoimmune disorders (e.g., systemic lupus erythematosus, rheumatoid arthritis). Clinical investigations reveal the overexpression of specific nucleic acid sensors in diseased tissues. In vivo animal models show enhanced disease progression associated with receptor activation. The involvement of nucleic acid sensors in various systemic conditions is further supported by studies reporting receptor knockout mice being either protected from or prone to disease. TLR9-mediated inflammation is also implicated in periodontal diseases. Considering that persistent inflammation in the oral cavity is associated with systemic diseases and that oral microbial DNA is isolated at distal sites, nucleic acid sensing may potentially be a link between oral and systemic diseases. In this review, we discuss recent advances in how intracellular PRRs respond to microbial nucleic acids and emerging views on the role of nucleic acid sensors in various systemic diseases. We also highlight new information on the role of intracellular PRRs in the pathogenesis of oral diseases including periodontitis

  19. A stable high-speed rotational transmission system based on nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Kun, E-mail: caikun1978@163.com [College of Water Resources and Architectural Engineering, Northwest A and F University, Yangling 712100 (China); State Key Laboratory of Structural Analysis for Industrial Equipment, Department of Engineering Mechanics, Faculty of Vehicle Engineering and Mechanics, Dalian University of Technology, Dalian 116024 (China); Yin, Hang; Wei, Ning [College of Water Resources and Architectural Engineering, Northwest A and F University, Yangling 712100 (China); Chen, Zhen [State Key Laboratory of Structural Analysis for Industrial Equipment, Department of Engineering Mechanics, Faculty of Vehicle Engineering and Mechanics, Dalian University of Technology, Dalian 116024 (China); Department of Civil and Environmental Engineering, University of Missouri, Columbia, Missouri 65211-2200 (United States); Shi, Jiao [Department of Civil and Environmental Engineering, University of Missouri, Columbia, Missouri 65211-2200 (United States)

    2015-01-12

    A stable rotational transmission system is designed with a single-walled carbon nanotube (SWCNT)-based motor and double-walled carbon nanotubes (DWCNTs)-based bearing. The system response is investigated using molecular dynamics (MD) simulation. It is found that the rotating motor can actuate the rotation of the inner tube in bearing because of the attraction between the two adjacent coaxial ends of motor and rotor (the inner tube in bearing). To have a stable nanostructure, each carbon atom on the adjacent ends of motor and rotor is bonded with a hydrogen atom. To obtain a stable high-speed rotational transmission system, both an armchair and a zigzag model are used in MD simulation. In each model, the motor with different diameters and rotational speeds is employed to examine the rotational transmission of corresponding DWCNTs. It is demonstrated that the long range van der Waals interaction between the adjacent ends of motor and rotor leads to a stable configuration of the adjacent ends, and further leads to a stable rotation of rotor when driven by a high-speed motor. As compared with the armchair model, the rotor in the zigzag model could reach a stable rotation mode much easier.

  20. A stable high-speed rotational transmission system based on nanotubes

    Science.gov (United States)

    Cai, Kun; Yin, Hang; Wei, Ning; Chen, Zhen; Shi, Jiao

    2015-01-01

    A stable rotational transmission system is designed with a single-walled carbon nanotube (SWCNT)-based motor and double-walled carbon nanotubes (DWCNTs)-based bearing. The system response is investigated using molecular dynamics (MD) simulation. It is found that the rotating motor can actuate the rotation of the inner tube in bearing because of the attraction between the two adjacent coaxial ends of motor and rotor (the inner tube in bearing). To have a stable nanostructure, each carbon atom on the adjacent ends of motor and rotor is bonded with a hydrogen atom. To obtain a stable high-speed rotational transmission system, both an armchair and a zigzag model are used in MD simulation. In each model, the motor with different diameters and rotational speeds is employed to examine the rotational transmission of corresponding DWCNTs. It is demonstrated that the long range van der Waals interaction between the adjacent ends of motor and rotor leads to a stable configuration of the adjacent ends, and further leads to a stable rotation of rotor when driven by a high-speed motor. As compared with the armchair model, the rotor in the zigzag model could reach a stable rotation mode much easier.

  1. A Novel Vision Sensing System for Tomato Quality Detection

    Directory of Open Access Journals (Sweden)

    Satyam Srivastava

    2014-01-01

    Full Text Available Producing tomato is a daunting task as the crop of tomato is exposed to attacks from various microorganisms. The symptoms of the attacks are usually changed in color, bacterial spots, special kind of specks, and sunken areas with concentric rings having different colors on the tomato outer surface. This paper addresses a vision sensing based system for tomato quality inspection. A novel approach has been developed for tomato fruit detection and disease detection. Developed system consists of USB based camera module having 12.0 megapixel interfaced with ARM-9 processor. Zigbee module has been interfaced with developed system for wireless transmission from host system to PC based server for further processing. Algorithm development consists of three major steps, preprocessing steps like noise rejection, segmentation and scaling, classification and recognition, and automatic disease detection and classification. Tomato samples have been collected from local market and data acquisition has been performed for data base preparation and various processing steps. Developed system can detect as well as classify the various diseases in tomato samples. Various pattern recognition and soft computing techniques have been implemented for data analysis as well as different parameters prediction like shelf life of the tomato, quality index based on disease detection and classification, freshness detection, maturity index detection, and different suggestions for detected diseases. Results are validated with aroma sensing technique using commercial Alpha Mos 3000 system. Accuracy has been calculated from extracted results, which is around 92%.

  2. Automatic Registration and Mosaicking System for Remotely Sensed Imagery

    Directory of Open Access Journals (Sweden)

    Emiliano Castejon

    2006-04-01

    Full Text Available Image registration is an important operation in many remote sensing applications and it, besides other tasks, involves the identification of corresponding control points in the images. As manual identification of control points may be time-consuming and tiring, several automatic techniques have been developed. This paper describes a system for automatic registration and mosaic of remote sensing images under development at The National Institute for Space Research (INPE and at The University of California, Santa Barbara (UCSB. The user can provide information to the system in order to speed up the registration process as well as to avoid mismatched control points. Based on statistical procedure, the system gives an indication of the registration quality. This allows users to stop the processing, to modify the registration parameters or to continue the processing. Extensive system tests have been performed with different types of data (optical, radar, multi-sensor, high-resolution images and video sequences in order to check the system performance. An online demo system is available on the internet ( which contains several examples that can be carried out using web browser.

  3. A Novel Vision Sensing System for Tomato Quality Detection.

    Science.gov (United States)

    Srivastava, Satyam; Boyat, Sachin; Sadistap, Shashikant

    2014-01-01

    Producing tomato is a daunting task as the crop of tomato is exposed to attacks from various microorganisms. The symptoms of the attacks are usually changed in color, bacterial spots, special kind of specks, and sunken areas with concentric rings having different colors on the tomato outer surface. This paper addresses a vision sensing based system for tomato quality inspection. A novel approach has been developed for tomato fruit detection and disease detection. Developed system consists of USB based camera module having 12.0 megapixel interfaced with ARM-9 processor. Zigbee module has been interfaced with developed system for wireless transmission from host system to PC based server for further processing. Algorithm development consists of three major steps, preprocessing steps like noise rejection, segmentation and scaling, classification and recognition, and automatic disease detection and classification. Tomato samples have been collected from local market and data acquisition has been performed for data base preparation and various processing steps. Developed system can detect as well as classify the various diseases in tomato samples. Various pattern recognition and soft computing techniques have been implemented for data analysis as well as different parameters prediction like shelf life of the tomato, quality index based on disease detection and classification, freshness detection, maturity index detection, and different suggestions for detected diseases. Results are validated with aroma sensing technique using commercial Alpha Mos 3000 system. Accuracy has been calculated from extracted results, which is around 92%.

  4. Quasisynchronization in Quorum Sensing Systems with Parameter Mismatches

    Directory of Open Access Journals (Sweden)

    Jianbao Zhang

    2014-01-01

    Full Text Available The paper investigates quasisynchronization in a communication system, which consists of cells communicating through quorum sensing. With the help of Lyapunov function method and Lur’e system approach, some sufficient conditions for quasisynchronization are presented, and a bound on the synchronization errors is derived. The obtained theoretical results show that the synchronization quality is influenced by two parameters detrimentally: the error bound depends almost linearly on the mismatches between cells and depends sensitively on the diffusion rates of the signals inward the cell membrane. Numerical experiments are carried out to verify the theoretical results.

  5. Initial results for compressive sensing in electronic support receiver systems

    CSIR Research Space (South Africa)

    Du Plessis, WP

    2011-04-01

    Full Text Available of 80 Gb/s which is 25% more than the optimistic assumption of 64 Gb/s for the fastest Serial RapidIO line. This means that data will take 25% longer to read from memory than it took to write into memory, so the above example will only be sampling 44... of compressive sensing are considered in Section V showing that real-time operation is possible. Finally, a brief conclusion and suggestions for future research are provided in Section VI. II. DATA RATES OF MODERN ES SYSTEMS AND THEIR EFFECT ON SYSTEM...

  6. On-chip highly sensitive saliva glucose sensing using multilayer films composed of single-walled carbon nanotubes, gold nanoparticles, and glucose oxidase

    Directory of Open Access Journals (Sweden)

    Wenjun Zhang

    2015-06-01

    Full Text Available It is very important for human health to rapidly and accurately detect glucose levels in biological environments, especially for diabetes mellitus. We proposed a simple, highly sensitive, accurate, convenient, low-cost, and disposable glucose biosensor on a single chip. A working (sensor electrode, a counter electrode, and a reference electrode are integrated on a single chip through micro-fabrication. The working electrode is functionalized through a layer-by-layer (LBL assembly of single-walled carbon nanotubes (SWNTs and multilayer films composed of chitosan (CS, gold nanoparticles (GNp, and glucose oxidase (GOx to obtain high sensitivity and accuracy. The glucose sensor has following features: (1 direct electron transfer between GOx and the electrode surface; (2 on-a-chip; (3 glucose detection down to 0.1 mg/dL (5.6 μM; (4 good sensing linearity over 0.017–0.81 mM; (5 high sensitivity (61.4 μA/mM-cm2 with a small reactive area (8 mm2; (6 fast response; (7 high reproducibility and repeatability; (8 reliable and accurate saliva glucose detection. Thus, this disposable biosensor will be an alternative for real time tracking of glucose levels from body fluids, e.g. saliva, in a noninvasive, pain-free, accurate, and continuous way. In addition to being used as a disposable glucose biosensor, it also provides a suitable platform for on-chip electrochemical sensing for other chemical agents and biomolecules.

  7. Compressed Sensing for Denoising in Adaptive System Identification

    CERN Document Server

    Hosseini, Seyed Hossein

    2012-01-01

    We propose a new technique for adaptive identification of sparse systems based on the compressed sensing (CS) theory. We manipulate the transmitted pilot (input signal) and the received signal such that the weights of adaptive filter approach the compressed version of the sparse system instead of the original system. To this end, we use random filter structure at the transmitter to form the measurement matrix according to the CS framework. The original sparse system can be reconstructed by the conventional recovery algorithms. As a result, the denoising property of CS can be deployed in the proposed method at the recovery stage. The experiments indicate significant performance improvement of proposed method compared to the conventional LMS method which directly identifies the sparse system. Furthermore, at low levels of sparsity, our method outperforms a specialized identification algorithm that promotes sparsity.

  8. Seismic wave detection system based on fully distributed acoustic sensing

    Science.gov (United States)

    Jiang, Yue; Xu, Tuanwei; Feng, Shengwen; Huang, Jianfen; Yang, Yang; Guo, Gaoran; Li, Fang

    2016-11-01

    This paper presents a seismic wave detection system based on fully distributed acoustic sensing. Combined with Φ- OTDR and PGC demodulation technology, the system can detect and acquire seismic wave in real time. The system has a frequency response of 3.05 dB from 5 Hz to 1 kHz, whose sampling interval of each channel of 1 meter on total sensing distance up to 10 km. By comparing with the geophone in laboratory, the data show that in the time domain and frequency domain, two waveforms coincide consistently, and the correlation coefficient could be larger than 0.98. Through the analysis of the data of the array experiment and the oil well experiment, DAS system shows a consistent time domain and frequency domain response and a clearer trail of seismic wave signal as well as a higher signal-noise rate which indicate that the system we proposed is expected to become the next generation of seismic exploration equipment.

  9. Hysteresis and compensation behaviors of spin-3/2 cylindrical Ising nanotube system

    Science.gov (United States)

    Kocakaplan, Yusuf; Keskin, Mustafa

    2014-09-01

    The hysteresis and compensation behaviors of the spin-3/2 cylindrical Ising nanotube system are studied within the framework of the effective-field theory with correlations. The effects of the Hamiltonian parameters are investigated on the magnetic and thermodynamic quantities, such as the total magnetization, hysteresis curves, and compensation behaviors of the system. Depending on the Hamiltonian parameters, some characteristic hysteresis behaviors are found, such as the existence of double and triple hysteresis loops. According to Néel classification nomenclature, the system displays Q-, R-, P-, N-, M-, and S- types of compensation behaviors for the appropriate values of the system parameters. We also compare our results with some recently published theoretical and experimental works and find a qualitatively good agreement.

  10. System and method for evaluating wind flow fields using remote sensing devices

    Science.gov (United States)

    Schroeder, John; Hirth, Brian; Guynes, Jerry

    2016-12-13

    The present invention provides a system and method for obtaining data to determine one or more characteristics of a wind field using a first remote sensing device and a second remote sensing device. Coordinated data is collected from the first and second remote sensing devices and analyzed to determine the one or more characteristics of the wind field. The first remote sensing device is positioned to have a portion of the wind field within a first scanning sector of the first remote sensing device. The second remote sensing device is positioned to have the portion of the wind field disposed within a second scanning sector of the second remote sensing device.

  11. System and method for evaluating wind flow fields using remote sensing devices

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, John; Hirth, Brian; Guynes, Jerry

    2016-12-13

    The present invention provides a system and method for obtaining data to determine one or more characteristics of a wind field using a first remote sensing device and a second remote sensing device. Coordinated data is collected from the first and second remote sensing devices and analyzed to determine the one or more characteristics of the wind field. The first remote sensing device is positioned to have a portion of the wind field within a first scanning sector of the first remote sensing device. The second remote sensing device is positioned to have the portion of the wind field disposed within a second scanning sector of the second remote sensing device.

  12. Magnetic nanotubes

    Science.gov (United States)

    Matsui, Hiroshi; Matsunaga, Tadashi

    2010-11-16

    A magnetic nanotube includes bacterial magnetic nanocrystals contacted onto a nanotube which absorbs the nanocrystals. The nanocrystals are contacted on at least one surface of the nanotube. A method of fabricating a magnetic nanotube includes synthesizing the bacterial magnetic nanocrystals, which have an outer layer of proteins. A nanotube provided is capable of absorbing the nanocrystals and contacting the nanotube with the nanocrystals. The nanotube is preferably a peptide bolaamphiphile. A nanotube solution and a nanocrystal solution including a buffer and a concentration of nanocrystals are mixed. The concentration of nanocrystals is optimized, resulting in a nanocrystal to nanotube ratio for which bacterial magnetic nanocrystals are immobilized on at least one surface of the nanotubes. The ratio controls whether the nanocrystals bind only to the interior or to the exterior surfaces of the nanotubes. Uses include cell manipulation and separation, biological assay, enzyme recovery, and biosensors.

  13. Frictional energy barrier and blocking temperature in water molecules and carbon nanotubes system

    Science.gov (United States)

    Zhang, Jianwei; Li, Jiaxi; Li, Wenfeng

    2015-03-01

    Water transport through hydrophobic channels of single-walled carbon nanotubes has attracted a lot interests, especially, various potential applications of SWCNTs have been proposed for designing novel nanofluidic devices. By adopting Molecular dynamics method, we investigated mechanics and statistics properties of water molecules escaping from a confined single-walled carbon nanotube. From our numerical MD simulations and statistical model, we determined the friction energy barrier of water molecules in (10.10) SWCNT is 9.88 kcal/mol, and which is the minimal energy for flowing a water molecules in CNT. By only using friction energy barrier and relaxation time parameter, our model can fit all different situations MD simulation results. In order to describing the frictional lock behavior of water molecules, we introduced a new blocking temperature, below this temperature (391K for our system), water is locked in CNT due to friction energy barrier. We found that the blocking temperature is closely related to system response time, and it also shows a linear behavior to frictional energy barrier. Furthermore, we found several other interesting statistics results when a water molecules leaving SWCNTs. This work was supported by NSFC No. 11274240 and NO. 51471119.

  14. Direct Measurement of Electron Transfer in Nanoscale Host-Guest Systems: Metallocenes in Carbon Nanotubes.

    Science.gov (United States)

    McSweeney, Robert L; Chamberlain, Thomas W; Baldoni, Matteo; Lebedeva, Maria A; Davies, E Stephen; Besley, Elena; Khlobystov, Andrei N

    2016-09-12

    Electron-transfer processes play a significant role in host-guest interactions and determine physicochemical phenomena emerging at the nanoscale that can be harnessed in electronic or optical devices, as well as biochemical and catalytic systems. A novel method for qualifying and quantifying the electronic doping of single walled carbon nanotubes (SWNTs) using electrochemistry has been developed that establishes a direct link between these experimental measurements and ab initio DFT calculations. Metallocenes such as cobaltocene and methylated ferrocene derivatives were encapsulated inside SWNTs (1.4 nm diameter) and cyclic voltammetry (CV) was performed on the resultant host-guest systems. The electron transfer between the guest molecules and the host SWNTs is measured as a function of shift in the redox potential (E1/2 ) of Co(II) /Co(I) , Co(III) /Co(II) and Fe(III) /Fe(II) . Furthermore, the shift in E1/2 is inversely proportional to the nanotube diameter. To quantify the amount of electron transfer from the guest molecules to the SWNTs, a novel method using coulometry was developed, allowing the mapping of the density of states and the Fermi level of the SWNTs. Correlated with theoretical calculations, coulometry provides an accurate indication of n/p-doping of the SWNTs.

  15. Remote sensing validation through SOOP technology: implementation of Spectra system

    Science.gov (United States)

    Piermattei, Viviana; Madonia, Alice; Bonamano, Simone; Consalvi, Natalizia; Caligiore, Aurelio; Falcone, Daniela; Puri, Pio; Sarti, Fabio; Spaccavento, Giovanni; Lucarini, Diego; Pacci, Giacomo; Amitrano, Luigi; Iacullo, Salvatore; D'Andrea, Salvatore; Marcelli, Marco

    2017-04-01

    The development of low-cost instrumentation plays a key role in marine environmental studies and represents one of the most innovative aspects of marine research. The availability of low-cost technologies allows the realization of extended observatory networks for the study of marine phenomena through an integrated approach merging observations, remote sensing and operational oceanography. Marine services and practical applications critically depends on the availability of large amount of data collected with sufficiently dense spatial and temporal sampling. This issue directly influences the robustness both of ocean forecasting models and remote sensing observations through data assimilation and validation processes, particularly in the biological domain. For this reason it is necessary the development of cheap, small and integrated smart sensors, which could be functional both for satellite data validation and forecasting models data assimilation as well as to support early warning systems for environmental pollution control and prevention. This is particularly true in coastal areas, which are subjected to multiple anthropic pressures. Moreover, coastal waters can be classified like case 2 waters, where the optical properties of inorganic suspended matter and chromophoric dissolved organic matter must be considered and separated by the chlorophyll a contribution. Due to the high costs of mooring systems, research vessels, measure platforms and instrumentation a big effort was dedicated to the design, development and realization of a new low cost mini-FerryBox system: Spectra. Thanks to the modularity and user-friendly employment of the system, Spectra allows to acquire continuous in situ measures of temperature, conductivity, turbidity, chlorophyll a and chromophoric dissolved organic matter (CDOM) fluorescences from voluntary vessels, even by non specialized operators (Marcelli et al., 2014; 2016). This work shows the preliminary application of this technology to

  16. A miniaturized and flexible optoelectronic sensing system for tactile skin

    Science.gov (United States)

    Ascari, L.; Corradi, P.; Beccai, L.; Laschi, C.

    2007-11-01

    This paper describes the development of a hybrid sensing module consisting of a general purpose electro-optical converter and three MEMS force sensors integrated into flexible substrates for tactile skin applications. The features of the converter, namely its flexible and thin substrate and small dimensions, programmability, optical coding and transmission of the information allow this versatile device to host different sensors, locally preprocess signals, translate this diverse information into a 'common language', and transmit it in a parallel, efficient and robust way to the processing unit. After discussing the major technical requirements, the design of the sensing, electrical and optical subsystems is illustrated, as well as the whole process for the module fabrication. A first characterization of a working prototype, hosting three MEMS force sensors and nine independent optical channels was performed. The global performance in terms of sensitivity, bandwidth and spatial sensing resolution make the presented module suitable to be used as basic element of a complete tactile system, conceived for robotic grasping and manipulation. Several solutions for mass production, improved optical properties and more efficient optical transmission are discussed.

  17. Amperometric sensing of anti-HIV drug zidovudine on Ag nanofilm-multiwalled carbon nanotubes modified glassy carbon electrode

    Energy Technology Data Exchange (ETDEWEB)

    Rafati, Amir Abbas, E-mail: aa_rafati@basu.ac.ir; Afraz, Ahmadreza

    2014-06-01

    The zidovudine (ZDV) is the first drug approved for the treatment of HIV virus infection. The detection and determination of this drug are very importance in human serum because of its undesirable effects. A new ZDV sensor was fabricated on the basis of nanocomposite of silver nanofilm (Ag-NF) and multiwalled carbon nanotubes (MWCNTs) immobilized on glassy carbon electrode (GCE). The modified electrodes were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), cyclic voltammetry (CV), and linear sweep voltammetry (LSV) techniques. Results showed that the electrodeposited silver has a nanofilm structure and further electrochemical studies showed that the prepared nanocomposite has high electrocatalytic activity and is appropriate for using in sensors. The amperometric technique under optimal conditions is used for the determination of ZDV ranging from 0.1 to 400 ppm (0.37 μM–1.5 mM) with a low detection limit of 0.04 ppm (0.15 μM) (S/N = 3) and good sensitivity. The prepared sensor possessed accurate and rapid response to ZDV and shows an average recovery of 98.6% in real samples. - Highlights: • New anti-HIV drug sensor was fabricated on the basis of nanomaterials composite. • The GCE modified by prepared hydrophilic MWCNT silver nanoparticles. • Silver nanofilm electrodeposited on MWCNT/GCE and characterized by SEM, EDX, CV and LSV • Response of electrode to ZDV was thoroughly investigated by electrochemical techniques.

  18. Enhanced Electrochemical Sensing with Carbon Nanotubes Modified with Bismuth and Magnetic Nanoparticles in a Lab-on-a-Chip.

    Science.gov (United States)

    Jothimuthu, Preetha; Hsu, Joe L; Chen, Robert; Inayathullah, Mohammed; Pothineni, Venkata Raveendra; Jan, Antony; Gurtner, Geoffrey C; Rajadas, Jayakumar; Nicolls, Mark R

    2016-09-01

    Iron plays an especially important role in human physiological functions and pathological impairments. The superior properties of carbon nanotubes (CNTs) and their modification with bismuth and magnetic nanoparticles as developed in this work have led to an extraordinary and novel material to facilitate ultrasensitive detection in the nanomolar range. Here, we present the development of an electrochemical sensor for detection of ferrous (Fe(2+)) and ferric (Fe(3+)) iron by means of CNTs modified with bismuth and magnetic nanoparticles for higher sensitivity of detection. The sensor fabrication includes microfabrication methodologies, soft lithography, and electrodeposition. Cyclic voltammetry and differential pulse voltammetry are used for the electroanalytical studies and detection of the ions in samples. The sensor has a dynamic range of detection from 0.01 nm to 10 mm. The performance of the sensor with modified CNTs was explored for sensitivity and specificity. CNTs, modified with bismuth and magnetic nanoparticles by means of electrodeposition, enhanced the detection limit significantly down to 0.01 nm.

  19. Synthesis of carbon nanotube-nickel nanocomposites using atomic layer deposition for high-performance non-enzymatic glucose sensing.

    Science.gov (United States)

    Choi, Taejin; Kim, Soo Hyeon; Lee, Chang Wan; Kim, Hangil; Choi, Sang-Kyung; Kim, Soo-Hyun; Kim, Eunkyoung; Park, Jusang; Kim, Hyungjun

    2015-01-15

    A useful strategy has been developed to fabricate carbon-nanotube-nickel (CNT-Ni) nanocomposites through atomic layer deposition (ALD) of Ni and chemical vapor deposition (CVD) of functionalized CNTs. Various techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), were used to characterize the morphology and the structure of as-prepared samples. It was confirmed that the products possess uniform Ni nanoparticles that are constructed by finely controlled deposition of Ni onto oxygen or bromine functionalized CNT surface. Electrochemical studies indicate that the CNT-Ni nanocomposites exhibit high electrocatalytic activity for glucose oxidation in alkaline solutions, which enables the products to be used in enzyme-free electrochemical sensors for glucose determination. It was demonstrated that the CNT-Ni nanocomposite-based glucose biosensor offers a variety of merits, such as a wide linear response window for glucose concentrations of 5 μM-2 mM, short response time (3 s), a low detection limit (2 μM), high sensitivity (1384.1 μA mM(-1) cm(-2)), and good selectivity and repeatability.

  20. Tribological properties of carbon nanotubes as lubricant additive in oil and water for a wheel–rail system

    Directory of Open Access Journals (Sweden)

    Jesús Antonio Carlos Cornelio

    2016-01-01

    Full Text Available Since their discovery in 1991 carbon nanotubes (CNTs have attracted much interest due to their remarkable mechanical, thermal, electrical, chemical and optical properties. In connection with their mechanical properties, CNTs have been studied in various forms for tribological applications including their use as lubricant additives for oil and water. In this work, the tribological properties of functionalized nanotubes (single and multi-walled modified with carboxylic acid when used as lubricant additives at different concentrations (0.01, 0.05% were studied under rolling-sliding conditions in a twin-disk testing machine. The tests were performed using 5% of creepage and pressures of 0.8 GPa and 1.1 GPa. The results indicated that the presence of carbon nanotubes leads to a decrease in both friction coefficient and wear rate for both systems studied (oil and water.

  1. A Portable Sensing System for Electronic Tongue Operations

    Directory of Open Access Journals (Sweden)

    Kilian Murphy

    2006-11-01

    Full Text Available A portable, low cost sensing system is described which interfaces to an electronictongue sensor. The sensor used is a voltammetric sensor which monitors electrochemicalreactions that occur in solutions. The sensor is able to test a range of liquids with differentelectrochemical properties without any hardware adjustments to the system. The system canautomatically adjust for the change in solution properties by performing a routine whichuses an auto-ranging feature to determine a current-to-voltage conversion of the sensor databy using a binary search strategy. This eliminates the intervention of the user to modify thesystem each time a new solution is tested. The effectiveness of the calibration routine wastested by carrying out cyclic voltammetry in two different solutions, 0.1M sulfuric acidsolution and the phosphate buffered solution of pH3. The sensor system was able toaccurately acquire the sensor data for each solution.

  2. Nanovesicle-Carbon Nanotube Hybrid Structures Mimicking Mammalian Pain Sensory System

    Science.gov (United States)

    Cho, Youngtac; Jin, Hye Jun; An, Jeong Mi; Park, Juhun; Moon, Seok Jun; Hong, Seunghun

    2015-03-01

    We developed a ``chemical-pain sensor'' based on a single-walled carbon nanotube-based field effect transistor (SWNT-FET) functionalized with rat pain sensory receptor, rat transient receptor potential vanilloid 1 (rTRPV1) mimicking a mammalian pain sensory system. The sensor can selectively detect chemical pain stimuli such as capsaicin and resiniferatoxin with a sensitivity of a 1 pM detection limit. Since this sensor allows one to quantitatively measure the concentration of chemical pain stimuli just like animal sensory systems, it can be used for various practical applications such as food screening. In addition, TRP families including rTRPV1 protein used for the sensor are now suggested as potential drug targets related to nerve and circulation disorders. Thus, the capability of measuring TRP responses using our sensor platform should open up other applications such as drug screening and basic research related with nerve and circulation systems.

  3. Development of a Near Ground Remote Sensing System

    Directory of Open Access Journals (Sweden)

    Yanchao Zhang

    2016-05-01

    Full Text Available Unmanned Aerial Vehicles (UAVs have shown great potential in agriculture and are increasingly being developed for agricultural use. There are still a lot of experiments that need to be done to improve their performance and explore new uses, but experiments using UAVs are limited by many conditions like weather and location and the time it takes to prepare for a flight. To promote UAV remote sensing, a near ground remote sensing platform was developed. This platform consists of three major parts: (1 mechanical structures like a horizontal rail, vertical cylinder, and three axes gimbal; (2 power supply and control parts; (3 onboard application components. This platform covers five degrees of freedom (DOFs: horizontal, vertical, pitch, roll, yaw. A stm32 ARM single chip was used as the controller of the whole platform and another stm32 MCU was used to stabilize the gimbal. The gimbal stabilizer communicates with the main controller via a CAN bus. A multispectral camera was mounted on the gimbal. Software written in C++ language was developed as the graphical user interface. Operating parameters were set via this software and the working status was displayed in this software. To test how well the system works, a laser distance meter was used to measure the slide rail’s repeat accuracy. A 3-axis vibration analyzer was used to test the system stability. Test results show that the horizontal repeat accuracy was less than 2 mm; vertical repeat accuracy was less than 1 mm; vibration was less than 2 g and remained at an acceptable level. This system has high accuracy and stability and can therefore be used for various near ground remote sensing studies.

  4. Development of a Near Ground Remote Sensing System.

    Science.gov (United States)

    Zhang, Yanchao; Xiao, Yuzhao; Zhuang, Zaichun; Zhou, Liping; Liu, Fei; He, Yong

    2016-05-06

    Unmanned Aerial Vehicles (UAVs) have shown great potential in agriculture and are increasingly being developed for agricultural use. There are still a lot of experiments that need to be done to improve their performance and explore new uses, but experiments using UAVs are limited by many conditions like weather and location and the time it takes to prepare for a flight. To promote UAV remote sensing, a near ground remote sensing platform was developed. This platform consists of three major parts: (1) mechanical structures like a horizontal rail, vertical cylinder, and three axes gimbal; (2) power supply and control parts; (3) onboard application components. This platform covers five degrees of freedom (DOFs): horizontal, vertical, pitch, roll, yaw. A stm32 ARM single chip was used as the controller of the whole platform and another stm32 MCU was used to stabilize the gimbal. The gimbal stabilizer communicates with the main controller via a CAN bus. A multispectral camera was mounted on the gimbal. Software written in C++ language was developed as the graphical user interface. Operating parameters were set via this software and the working status was displayed in this software. To test how well the system works, a laser distance meter was used to measure the slide rail's repeat accuracy. A 3-axis vibration analyzer was used to test the system stability. Test results show that the horizontal repeat accuracy was less than 2 mm; vertical repeat accuracy was less than 1 mm; vibration was less than 2 g and remained at an acceptable level. This system has high accuracy and stability and can therefore be used for various near ground remote sensing studies.

  5. Development of a Near Ground Remote Sensing System

    Science.gov (United States)

    Zhang, Yanchao; Xiao, Yuzhao; Zhuang, Zaichun; Zhou, Liping; Liu, Fei; He, Yong

    2016-01-01

    Unmanned Aerial Vehicles (UAVs) have shown great potential in agriculture and are increasingly being developed for agricultural use. There are still a lot of experiments that need to be done to improve their performance and explore new uses, but experiments using UAVs are limited by many conditions like weather and location and the time it takes to prepare for a flight. To promote UAV remote sensing, a near ground remote sensing platform was developed. This platform consists of three major parts: (1) mechanical structures like a horizontal rail, vertical cylinder, and three axes gimbal; (2) power supply and control parts; (3) onboard application components. This platform covers five degrees of freedom (DOFs): horizontal, vertical, pitch, roll, yaw. A stm32 ARM single chip was used as the controller of the whole platform and another stm32 MCU was used to stabilize the gimbal. The gimbal stabilizer communicates with the main controller via a CAN bus. A multispectral camera was mounted on the gimbal. Software written in C++ language was developed as the graphical user interface. Operating parameters were set via this software and the working status was displayed in this software. To test how well the system works, a laser distance meter was used to measure the slide rail’s repeat accuracy. A 3-axis vibration analyzer was used to test the system stability. Test results show that the horizontal repeat accuracy was less than 2 mm; vertical repeat accuracy was less than 1 mm; vibration was less than 2 g and remained at an acceptable level. This system has high accuracy and stability and can therefore be used for various near ground remote sensing studies. PMID:27164111

  6. Load Sensing Systems - A Review of the Research Contributions Throughout the Last Decades

    DEFF Research Database (Denmark)

    Pedersen, Henrik Clemmensen; Andersen, Torben Ole; Hansen, Michael Rygaard

    2004-01-01

    The paper describes the major research contributions made in the research of hydraulic load sensing systems throughout the last decades. Furthermore, the paper investigates the efforts put into electronic load sensing and the most promising alternatives to load sensing systems. Finally, the paper...

  7. 78 FR 44536 - Proposed Information Collection; Comment Request; Licensing of Private Remote-Sensing Space Systems

    Science.gov (United States)

    2013-07-24

    ... of Private Remote-Sensing Space Systems AGENCY: National Oceanic and Atmospheric Administration (NOAA... of remote-sensing space systems. The information in applications and subsequent reports is needed to ensure compliance with the Land Remote- Sensing Policy Act of 1992 and with the national security...

  8. 75 FR 32360 - Proposed Information Collection; Comment Request; Licensing of Private Remote-Sensing Space Systems

    Science.gov (United States)

    2010-06-08

    ... of Private Remote-Sensing Space Systems AGENCY: National Oceanic and Atmospheric Administration (NOAA... the licensing of private operators of remote-sensing space systems. The information in applications and subsequent reports is needed to ensure compliance with the Land Remote- Sensing Policy Act of...

  9. 15 CFR 960.12 - Data policy for remote sensing space systems.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Data policy for remote sensing space... REGULATIONS OF THE ENVIRONMENTAL DATA SERVICE LICENSING OF PRIVATE REMOTE SENSING SYSTEMS Licenses § 960.12 Data policy for remote sensing space systems. (a) In accordance with the Act, if the U.S....

  10. Self-filtering oscillations in carbon nanotube hetero-junctions.

    Science.gov (United States)

    Scarpa, F; Narojczyk, J W; Wojciechowski, K W; Inman, D J

    2011-11-18

    We evaluate the vibrational properties of single-wall carbon nanotube (SWCNT) hetero-junction (HJ) oscillators using a hybrid atomistic-continuum approach validated by molecular mechanics/molecular dynamics simulations. The SWCNT-HJs show a broken symmetry topology of their mode shapes, with striction effects caused on the bending and radial modes by the combined effect of the HJ and the tube with the thinner radius. The single-wall nanotube HJs also show selective mass sensing properties based solely on the geometry and type of the boundary conditions of the specific nanostructure. This unusual behaviour has not been observed so far in classical SWCNT systems.

  11. System and method for statistically monitoring and analyzing sensed conditions

    Science.gov (United States)

    Pebay, Philippe P.; Brandt, James M. , Gentile; Ann C. , Marzouk; Youssef M. , Hale; Darrian J. , Thompson; David C.

    2010-07-13

    A system and method of monitoring and analyzing a plurality of attributes for an alarm condition is disclosed. The attributes are processed and/or unprocessed values of sensed conditions of a collection of a statistically significant number of statistically similar components subjected to varying environmental conditions. The attribute values are used to compute the normal behaviors of some of the attributes and also used to infer parameters of a set of models. Relative probabilities of some attribute values are then computed and used along with the set of models to determine whether an alarm condition is met. The alarm conditions are used to prevent or reduce the impact of impending failure.

  12. Thermally induced local failures in quasi-one-dimensional systems: collapse in carbon nanotubes, neckling in nanowires, bubbles in DNA

    Energy Technology Data Exchange (ETDEWEB)

    Nisoli, Cristiano [Los Alamos National Laboratory; Lookman, Turab [Los Alamos National Laboratory; Saxena, Avadh [Los Alamos National Laboratory; Abraham, Douglas [RUDOLF PEIERLS CENTRE

    2009-01-01

    Quasi one dimensional systems can suffer local structural failures-broadly defined-along their length: for instance, carbon nanotubes can collapse, nanowires can show bottlenecks below which conductance drops, bubbles open in DNA. We present a formalism to explore the occurrence of those thermally activated failures in complete generality, to calculate the average length between them as a function of the thermodynamic observables.

  13. Positron Bunch Radiation in the System of Tightly-Packed Nanotubes

    CERN Document Server

    Gevorgyan, Koryun; Gevorgyan, Hayk

    2015-01-01

    The problem of channeling radiation of positron bunch in the system of packed nanotubes was investigated in the present work. Used the model of harmonic potential which is justified since on the one hand the number of positrons in the region near the axis of nanotube is small, and on the other hand their contribution to the formation of the total radiation is also small. The problem is solved in the dipole approximation. The radiation at first harmonic occurs at zero angle too. At zero angle are radiated both extremely hard and extremely soft photons due to the medium polarization. The frequency-angular distribution of number of emitted photons was received. The distribution does not depend on the azimuthal angle, since the task has cylindrical symmetry. Radiation at the zero angle is fully circularly polarized. For formation of radiation there is an energy threshold: lower threshold is due to the polarization of medium, the upper threshold depends on the oscillation amplitude of channelling positrons. When t...

  14. Analytical applications of a carbon nanotubes composite modified with copper microparticles as detector in flow systems.

    Science.gov (United States)

    Arribas, Alberto Sánchez; Bermejo, Esperanza; Chicharro, Manuel; Zapardiel, Antonio; Luque, Guillermina L; Ferreyra, Nancy F; Rivas, Gustavo A

    2006-09-08

    In this work we report on the successful use of a composite prepared by dispersion of multi-wall carbon nanotubes (1-5 microm length, 20-50 nm diameter) and copper microparticles within mineral oil as detector for amino acids quantification in flow injection analysis and capillary electrophoresis. The resulting electrode displays a highly sensitive amperometric detection of amino acids, based on the copper dissolution facilitated by the strong activity of amino acids as ligands of Cu(II). The sensor makes possible the detection of amino acids, electroactive or not, at very low potentials (0.000 V) and physiological pH. A correlation between the sensitivity for the amino acids and the amount of copper within the composite is observed, demonstrating the importance of the metal in the sensor response. The best analytical performance is obtained for the electrode containing 12.0% (w/w) copper. The excellent results obtained with the carbon nanotube paste electrodes containing copper (CNTPE-Cu) as detector in flow systems makes them an interesting alternative for further analytical applications involving different bioanalytes.

  15. Soft sensing of system parameters in membrane distillation

    KAUST Repository

    Laleg-Kirati, Taous-Meriem

    2017-03-23

    Various examples of methods and systems are provided for soft sensing of system parameters in membrane distillation (MD). In one example, a system includes a MD module comprising a feed side and a permeate side separated by a membrane boundary layer; and processing circuitry configured to estimate feed solution temperatures and permeate solution temperatures of the MD module using monitored outlet temperatures of the feed side and the permeate side. In another example, a method includes monitoring outlet temperatures of a feed side and a permeate side of a MD module to determine a current feed outlet temperature and a current permeate outlet temperature; and determining a plurality of estimated temperature states of a membrane boundary layer separating the feed side and the permeate side of the MD module using the current feed outlet temperature and the current permeate outlet temperature.

  16. The application of carbon nanotubes in target drug delivery systems for cancer therapies

    Directory of Open Access Journals (Sweden)

    Zhang Zhenzhong

    2011-01-01

    Full Text Available Abstract Among all cancer treatment options, chemotherapy continues to play a major role in killing free cancer cells and removing undetectable tumor micro-focuses. Although chemotherapies are successful in some cases, systemic toxicity may develop at the same time due to lack of selectivity of the drugs for cancer tissues and cells, which often leads to the failure of chemotherapies. Obviously, the therapeutic effects will be revolutionarily improved if human can deliver the anticancer drugs with high selectivity to cancer cells or cancer tissues. This selective delivery of the drugs has been called target treatment. To realize target treatment, the first step of the strategies is to build up effective target drug delivery systems. Generally speaking, such a system is often made up of the carriers and drugs, of which the carriers play the roles of target delivery. An ideal carrier for target drug delivery systems should have three pre-requisites for their functions: (1 they themselves have target effects; (2 they have sufficiently strong adsorptive effects for anticancer drugs to ensure they can transport the drugs to the effect-relevant sites; and (3 they can release the drugs from them in the effect-relevant sites, and only in this way can the treatment effects develop. The transporting capabilities of carbon nanotubes combined with appropriate surface modifications and their unique physicochemical properties show great promise to meet the three pre-requisites. Here, we review the progress in the study on the application of carbon nanotubes as target carriers in drug delivery systems for cancer therapies.

  17. Single wall carbon nanotube electrode system capable of quantitative detection of CD4(+) T cells.

    Science.gov (United States)

    Kim, Joonhyub; Park, Gayoung; Lee, Seoho; Hwang, Suk-Won; Min, Namki; Lee, Kyung-Mi

    2017-04-15

    Development of CNT-based CD4(+) T cell imunosensors remains in its infancy due to the poor immobilization efficiency, lack of reproducibility, and difficulty in providing linear quantification. Here, we developed a fully-integrated single wall carbon nanotube (SWCNT)-based immunosensor capable of selective capture and linear quantification of CD4(+) T cells with greater dynamic range. By employing repeated two-step oxygen (O2) plasma treatment processes with 35 days of recovery periods, we achieved the enhanced functionalization of the CNT surface and the removal of the byproduct of spray-coated SWCNTs that hinders charge transfer and stable CD4(+) T cell sensing. As a result, a linear electrochemical signal was generated in direct proportion to the bound cells. The slope of a SWCNT electrode in a target concentration range (10(2)~10(6)cells/mL) was 4.55×10(-2)μA per concentration decade, with the lowest detection limit of 1×10(2)cells/mL. Since the reduced number of CD4(+) T cell counts in patients' peripheral blood corresponds to the progression of HIV disease, our CD4(+) T cell-immunosensor provides a simple and low-cost platform which can fulfill the requirement for the development of point-of-care (POC) diagnostic technologies for human immunodeficiency virus (HIV) patients in resource-limited countries.

  18. An operational satellite remote sensing system for ocean fishery

    Institute of Scientific and Technical Information of China (English)

    MAOZhihua; ZHUQiankun; PANDelu

    2004-01-01

    Ocean environmental information is very important to supporting the fishermen in fishing and satellite remote sensing technology can provide it in large scale and in near real-time. Ocean fishery locations are always far away beyond the coverage of the satellite data received by a land-based satellite receiving station. A nice idea is to install the satellite ground station on a fishing boat. When the boat moves to a fishery location, the station can receive the satellite data to cover the fishery areas. One satellite remote sensing system was once installed in a fishing boat and served fishing in the North Pacific fishery areas when the boat stayed there. The system can provide some oceanic environmental charts such as sea surface temperature (SST) and relevant derived products which are in most popular use in fishery industry. The accuracy of SST is the most important and affects the performance of the operational system, which is found to be dissatisfactory. Many factors affect the accuracy of SST and it is difficult to increase the accuracy by SST retrieval algorithms and clouds detection technology. A new technology of temperature error control is developed to detect the abnormity of satellite-measured SST. The performance of the technology is evaluated to change the temperature bias from-3.04 to 0.05 ℃ and the root mean square (RMS) from 5.71 to 1.75 ℃. It is suitable for employing in an operational satellite-measured SST system and improves the performance of the system in fishery applications. The system has been running for 3 a and proved to be very useful in fishing. It can help to locate the candidates of the fishery areas and monitor the typhoon which is very dangerous to the safety of fishing boats.

  19. Structure-property relationships in carbon nanotube-polymer systems: Influence of noncovalent stabilization techniques

    Science.gov (United States)

    Liu, Lei

    A variety of experiments were carried out to study the dispersion and microstructure of carbon nanotubes in aqueous suspensions and polymer composites with the goal to improve the electrical conductivity of the composites containing nanotubes. Epoxy composites containing covalently and noncovalently functionalized nanotubes were compared in terms of electrical and mechanical behavior. Covalent functionalization of nanotubes is based on chemical attachments of polyethylenimine (PEI) whereas noncovalent functionalization takes place through physical mixing of nanotubes and PEI. The electrical conductivity is reduced in composites containing covalently functionalized nanotubes due to damage of the tube's conjugated surface that reduces intrinsic conductivity. Conversely, the mechanical properties are always better for epoxy composites containing covalently functionalized nanotubes. Clay particles were used as a rigid dispersing aid for nanotubes in aqueous suspensions and epoxy composites. When both nanotubes and clay were introduced into water by sonication, the suspension is stable for weeks, whereas the nanotubes precipitate almost instantly for the suspension without clay. In epoxy composites, nanotubes form separated clusters of aggregation, whereas a continuous three-dimensional nanotube network is achieved when clay is introduced. Electrical conductivity of the epoxy composite is shown to significantly improve with a small addition of clay and the percolation threshold is simultaneously decreased (from 0.05 wt% nanotubes, when there is no clay, to 0.01 wt% when 2 wt% clay is introduced). The addition of clay can also improve the mechanical properties of the composites, especially at higher clay concentration. Weak polyelectrolytes (i.e., pH-responsive polymers) were also studied for their interaction with nanotubes and the electrical properties of the dried composite films. When dispersed by sonication, Nanotubes show pH-dependent dispersion and stability in

  20. Computational studies of small carbon and iron-carbon systems relevant to carbon nanotube growth.

    Science.gov (United States)

    Duan, Haiming; Rosén, Arne; Harutyunyan, Avetik; Curtarolo, Stefano; Bolton, Kim

    2008-11-01

    Density functional theory (DFT) calculations show that dimers and longer carbon strings are more stable than individual atoms on Fe(111) surfaces. It is therefore necessary to consider the formation of these species on the metal surfaces and their effect on the mechanism of single-walled nanotube (SWNT) growth. The good agreement between the trends (energies and structures) obtained using DFT and those based on the Brenner and AIREBO models indicate that these analytic models provide adequate descriptions of the supported carbon systems needed for valid molecular dynamics simulations of SWNT growth. In contrast, the AIREBO model provides a better description of the relative energies for isolated carbon species, and this model is preferred over the Brenner potential when simulating SWNT growth in the absence of metal particles. However, the PM3 semiempirical model appears to provide an even better description for these systems and, given sufficient computer resources, direct dynamics methods based on this model may be preferred.

  1. Multiwalled carbon nanotubes and fluoroelastomer antistatic nanocomposite for automotive fuel system components

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seok; Park, Seong Hwan; Ha, Kiryong [Keimyung University, Daegu (Korea, Republic of); Lee, Jong Cheol [Jin-Yang Oil Seal Co., Ltd., Daegu (Korea, Republic of)

    2016-03-15

    Fluoroelastomer (FKM) composites, reinforced with multiwalled carbon nanotubes (MWNTs), were prepared by conventional method to determine the possibility of using MWNTs to develop an antistatic composite in automotive fuel systems. The results obtained from the composite containing 0-9 phr of MWNTs were compared. A 5 points increase in hardness was achieved with the addition of only 1 phr of MWNTs and 9 phr added FKM composite was increased 6.4MPa in tensile strength compared to the MWNTs unfilled FKM composite. In addition, electrical conductivity increased from 0 to 1.039 Scm{sup -1} with increase in the MWNTs concentration, and the dynamic damping property was increased in the rubbery state region accordingly. These phenomena can be explained by the MWNTs networks formed in FKM matrix. This research will therefore be useful in the development of an antistatic rubber composite for fuel system components, which are deformed or vibrated while in operation.

  2. A closed-loop neurobotic system for fine touch sensing

    Science.gov (United States)

    Bologna, L. L.; Pinoteau, J.; Passot, J.-B.; Garrido, J. A.; Vogel, J.; Ros Vidal, E.; Arleo, A.

    2013-08-01

    Objective. Fine touch sensing relies on peripheral-to-central neurotransmission of somesthetic percepts, as well as on active motion policies shaping tactile exploration. This paper presents a novel neuroengineering framework for robotic applications based on the multistage processing of fine tactile information in the closed action-perception loop. Approach. The integrated system modules focus on (i) neural coding principles of spatiotemporal spiking patterns at the periphery of the somatosensory pathway, (ii) probabilistic decoding mechanisms mediating cortical-like tactile recognition and (iii) decision-making and low-level motor adaptation underlying active touch sensing. We probed the resulting neural architecture through a Braille reading task. Main results. Our results on the peripheral encoding of primary contact features are consistent with experimental data on human slow-adapting type I mechanoreceptors. They also suggest second-order processing by cuneate neurons may resolve perceptual ambiguities, contributing to a fast and highly performing online discrimination of Braille inputs by a downstream probabilistic decoder. The implemented multilevel adaptive control provides robustness to motion inaccuracy, while making the number of finger accelerations covariate with Braille character complexity. The resulting modulation of fingertip kinematics is coherent with that observed in human Braille readers. Significance. This work provides a basis for the design and implementation of modular neuromimetic systems for fine touch discrimination in robotics.

  3. Distributed vibration fiber sensing system based on Polarization Diversity Receiver

    Science.gov (United States)

    Zhang, Junan; Jiang, Peng; Hu, Zhengliang; Hu, Yongming

    2016-10-01

    In this paper, we propose a distributed vibration fiber sensing system based on Polarization Diversity Receiver(PDR). We use Acoustic Optical Modulator(AOM) to generate pulse light and an unbalanced M-Z interferometer to generate two pulse light with a certain time delay in the same period. As the pulse lights propagating in fibers, the Backward Rayleigh scattering lights will interfere with each other. The vibration on the fiber will change the length and refractive index of fiber which results in the change of the phase of the interference signal. Hence, one arm of the M-Z interferometer is modulated by a sinusoidal phase-generated carrier(PGC) signal, and PGC demodulation algorithm has been used to acquire phase information from the Backward Rayleigh scattering lights. In order to overcome the influence of polarization-induced fading and enhance Signal Noise Ratio(SNR), we set a PDR before the photo detector. The Polarization Diversity Receiver segregates the interfere light into two lights with orthogonal states of polarization. Hence, there is always one channel has a better interfere light signal. The experiments are presented to verify the effectiveness of the distributed vibration fiber sensing system proposed.

  4. RSComPro: An Open Communication Protocol for Remote Sensing Systems

    DEFF Research Database (Denmark)

    Vasiljevic, Nikola; Trujillo, Juan-José

    The remote sensing protocol (RSComPro) is a communication protocol, which has been developed for controlling multiple remote sensing systems simultaneously through a UDP/IP and TPC/IP network. This protocol is meant to be open to the remote sensing community. The scope is the implementation of so...

  5. RSComPro: An Open Communication Protocol for Remote Sensing Systems

    DEFF Research Database (Denmark)

    Vasiljevic, Nikola; Trujillo, Juan-José

    The remote sensing protocol (RSComPro) is a communication protocol which has been developed for controlling multiple remote sensing systems simultaneously through a UDP/IP and TPC/IP network. This protocol is meant to be open to the remote sensing community. The scope is the implementation of so...

  6. Carbon nanotubes as a novel drug delivery system for anticancer therapy: a review

    Energy Technology Data Exchange (ETDEWEB)

    Kushwaha, Swatantra Kumar Singh; Ghoshal, SauravI; Rai, Awani Kumar, E-mail: swatantrakushwaha@yahoo.co.in [Pranveer Singh Institute of Technology, Kanpur (India); Singh, Satyawan [Saroj Institute of Technology and Management, Lucknow (India)

    2013-10-15

    Carbon nanotubes (CNTs) were discovered in 1991 and shown to have certain unique physicochemical properties, attracting considerable interest in their application in various fields including drug delivery. The unique properties of CNTs such as ease of cellular uptake, high drug loading, thermal ablation, among others, render them useful for cancer therapy. Cancer is one of the most challenging diseases of modern times because its therapy involves distinguishing normal healthy cells from affected cells. Here, CNTs play a major role because phenomena such as EPR, allow CNTs to distinguish normal cells from affected ones, the Holy Grail in cancer therapy. Considerable work has been done on CNTs as drug delivery systems over the last two decades. However, concerns over certain issues such as biocompatibility and toxicity have been raised and warrant extensive research in this field. (author)

  7. Carbon nanotubes as a novel drug delivery system for anticancer therapy: a review

    Directory of Open Access Journals (Sweden)

    Swatantra Kumar Singh Kushwaha

    2013-12-01

    Full Text Available Carbon nanotubes (CNTs were discovered in 1991 and shown to have certain unique physicochemical properties, attracting considerable interest in their application in various fields including drug delivery. The unique properties of CNTs such as ease of cellular uptake, high drug loading, thermal ablation, among others, render them useful for cancer therapy. Cancer is one of the most challenging diseases of modern times because its therapy involves distinguishing normal healthy cells from affected cells. Here, CNTs play a major role because phenomena such as EPR, allow CNTs to distinguish normal cells from affected ones, the Holy Grail in cancer therapy. Considerable work has been done on CNTs as drug delivery systems over the last two decades. However, concerns over certain issues such as biocompatibility and toxicity have been raised and warrant extensive research in this field.

  8. Androgynous, Reconfigurable Closed Loop Feedback Controlled Low Impact Docking System With Load Sensing Electromagnetic Capture Ring

    Science.gov (United States)

    Lewis, James L. (Inventor); Carroll, Monty B. (Inventor); Morales, Ray H. (Inventor); Le, Thang D. (Inventor)

    2002-01-01

    The present invention relates to a fully androgynous, reconfigurable closed loop feedback controlled low impact docking system with load sensing electromagnetic capture ring. The docking system of the present invention preferably comprises two Docking- assemblies, each docking assembly comprising a load sensing ring having an outer face, one of more electromagnets, one or more load cells coupled to said load sensing ring. The docking assembly further comprises a plurality of actuator arms coupled to said load sensing ring and capable of dynamically adjusting the orientation of said load sensing ring and a reconfigurable closed loop control system capable of analyzing signals originating from said plurality of load cells and of outputting real time control for each of the actuators. The docking assembly of the present invention incorporates an active load sensing system to automatically dynamically adjust the load sensing ring during capture instead of requiring significant force to push and realign the ring.

  9. Detection of Septic System Performance via Remote Sensing Technologies

    Science.gov (United States)

    Patterson, A. H.; Kuszmaul, J. S.; Harvey, C.

    2005-05-01

    Failing and improperly managed septic systems can affect water quality in their environs and cause health problems for individuals or community residents. When unchecked, failing systems can allow disease-causing pathogens to enter groundwater aquifers and pollute surface waters, contaminating drinking water, recreational waterways, and fishing grounds. Early detection of septic system leakage and failure can limit the extent of these problems. External symptoms which occur over an improperly functioning septic system can include lush or greener growth of vegetation, distress of vegetation, excessive soil moisture levels, or pooling of surface effluent. The use of remote sensing technologies coupled with attainable permit records to successfully identify these features could enable the appropriate agencies to target problem areas without extensive field inspection. High-resolution, airborne imagery was identified as having the potential to detect relative changes in soil moisture, to delineate individual leach fields, and to locate effluent discharges into water bodies. In addition, vegetation patterns responding to nutrient-rich effluent and increased soil moisture could be examined using a vegetation index. Both thermal- and color-infrared imagery were acquired for a study area in Jackson County, Mississippi, adjacent to the Gulf of Mexico. Within this coastal neighborhood known to have significant septic system failures, over 50 volunteer residents supplied information regarding the function of their systems and access to their property. Following data collection, regression methods were used to nominate the major indicators of malfunctioning systems. A ranking system for the "level of function" was derived from these analyses. A model was created which inputs data from attainable records and imagery analysis and outputs a predicted level of septic system function. The end product of this research will permit evaluation of septic system performance to be

  10. Removal of micropollutants and NOM in carbon nanotube-UF membrane system from seawater.

    Science.gov (United States)

    Heo, Jiyong; Joseph, Lesley; Yoon, Yeomin; Park, Yong-Gyun; Her, Namguk; Sohn, Jinsik; Yoon, Seong-Hoon

    2011-01-01

    One of the main problems for seawater reverse osmosis desalination is membrane fouling associated with natural organic matter. Bisphenol-A (BPA) and 17alpha-ethinylestradiol (EE2) are well-known endocrine-disrupting compounds that have been detected in wastewater and seawater. In this study, the contribution of carbon nanotubes (CNTs, single-walled carbon nanotubes) to membrane fouling control and the potential adsorption mechanisms of BPA and EE2 were investigated using artificial seawater (ASW) in a bench scale ultrafiltration (UF) membrane coupled with CNTs. For high ionic strength ASW, UVA254 nm is a good alternative for highly aromatic dissolved organic carbon (DOC) determination, with a very strong linear relationship (R2 > or = 0.99) with increasing DOC concentrations. Approximately 80% of DOC in ASW was rejected by the CNT-UF system where 31% of DOC was removed due to adsorption by CNTs. The presence of CNTs shows a 20% increase in membrane flux in ASW. A strong linear correlation between retention and adsorption of BPA and EE2 was obtained. The percentage of adsorption/retention of BPA and EE2 in UF-CNTs follows the order: 94.0/96.6 (DI + CNTs, EE2) > 86.2/90.0 (ASW + CNTs, EE2) > 73.6/78.9 (DI + CNTS, BPA) > or = 74.1/77.3 (ASW + CNTS, BPA) > 29.8/29.8 (ASW, EE2) approximately equal to 27.3/27.3 (ASW, BPA) > or = 25.3/25.3 (DI, EE2) approximately equal to 24.8/24.8 (DI, BPA). This indicates that retention by the UF-CNT system is mainly due to adsorption. Overall, EE2 adsorption was greater than BPA during the UF-CNT experiments, presumably due to the higher hydrophobicity of EE2 than BPA.

  11. Development of new techniques for functionalizing single-wall carbon nanotubes for composite and biological systems

    Science.gov (United States)

    Hudson, Jared Lee

    Building from established methods of using diazonium salts to derivatize single-wall carbon nanotubes (SWNTs), new methodologies for achieving functionalized individual nanotubes that are compatible with a wide variety of materials have been developed. The use of aryl triazenes as diazonium precursors to functionalize surfactant stabilized suspensions of individual SWNTs has resulted in the ability to synthesize more complex molecules bearing a diazonium salt precursor. Prior to this work, such functionality was difficult to install in complex molecules due to the required linearity of diazonium salt synthesis. A protocol to access individualized SWNTs without the use of scale-limiting techniques such as high powered sonication and centrifugation was achieved by the use of oleum as a solvent for underivatized SWNTs. This disentangled suspension of SWNTs was then treated with a modification of an established in-situ diazonium functionalization protocol to yield alcohol and water-soluble, exfoliated, nonroping SWNTs. Functionalized SWNTs were used as polymerization initiators for both anionic and atom transfer radical polymerization. They were used to reinforce poly(dimethylsiloxane) and poly(propylene fumarate) based composites. The functionalized SWNTs were also used as a support for neuronal interface systems and to reinforce the collagen network in rat cervical tissue. Through continued functionalization and PEGylation (poly(ethylene glycol) attachment) of cut SWNTs, the development of a SWNT-based, viable nanovector core has been achieved. Continued functionalization provides one with the ability to further derivatize aqueous suspensions of previously functionalized SWNTs, while the PEGylation of cut SWNTs offers solubility in water, irrigation saline, and phosphate buffered saline. Using the developed SWNT-based nanovector core, molecules that are relevant for attachment to a nanovector were targeted. This includes a fluorescein-5-isothiocyanate (FITC

  12. Evaluating mirror alignment systems using the optical sensing matrix

    Energy Technology Data Exchange (ETDEWEB)

    Mantovani, M [Universita di Siena, INFN Pisa (Italy); Freise, A [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)], E-mail: mantovan@ego-gw.it

    2008-07-15

    The most sensitive gravitational-wave detectors today are based on large-scale laser interferometers whose optics are suspended from pendulums to decouple the instrument from seismic motion. Complex control systems are required to set and maintain the microscopic position of each mirror at a precisely defined value. Such control systems use the interferometer signals as input signals, and ideally it is designed such that the degrees of freedom (mirror positions) are well decoupled in the interferometer signals. However, this is not always feasible, in particular the mirror alignment control signals in interferometric gravitational wave detectors often show strong couplings between the different degrees of freedom. In this paper we will describe a simple and powerful method to quantify in advance the performances of an alignment control system by analyzing the optical matrix of the proposed read-out system. We will motivate the method using a Fabry-Perot cavity as an example, and we will further present results for the Virgo alignment system where this method was used to characterize and improve the alignment sensing scheme.

  13. Influence of Organo-Modified Laponite on the Percolation Behavior of the Systems Based on Polyethylene Glycol and Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    E.A. Lysenkov

    2016-11-01

    Full Text Available The electric properties of the systems based on polyethylene glycol (PEG, carbon nanotubes (CNT and laponite is studied using methods of impedance spectroscopy and optical microscopy. It is rotined that at introduction to the system of organo-modified laponite (OLP leads to the shift of the percolation threshold to the area of lower concentrations of CNT. The modeling of impedance spectrums by the method of equivalent circuits is conducted for the systems based on PEG. It is set that the introduction of OLP more than 0,4 % in the system results in the considerable decrease of electrical conductivity. This effect is explained that the platelets of OLP hinder the formation of direct contacts between nanotubes.

  14. Radar sensing via a Micro-UAV-borne system

    Science.gov (United States)

    Catapano, Ilaria; Ludeno, Giovanni; Gennarelli, Gianluca; Soldovieri, Francesco; Rodi Vetrella, Amedeo; Fasano, Giancarmine

    2017-04-01

    In recent years, the miniaturization of flight control systems and payloads has contributed to a fast and widespread diffusion of micro-UAV (Unmanned Aircraft Vehicle). While micro-UAV can be a powerful tool in several civil applications such as environmental monitoring and surveillance, unleashing their full potential for societal benefits requires augmenting their sensing capability beyond the realm of active/passive optical sensors [1]. In this frame, radar systems are drawing attention since they allow performing missions in all-weather and day/night conditions and, thanks to the microwave ability to penetrate opaque media, they enable the detection and localization not only of surface objects but also of sub-surface/hidden targets. However, micro-UAV-borne radar imaging represents still a new frontier, since it is much more than a matter of technology miniaturization or payload installation, which can take advantage of the newly developed ultralight systems. Indeed, micro-UAV-borne radar imaging entails scientific challenges in terms of electromagnetic modeling and knowledge of flight dynamics and control. As a consequence, despite Synthetic Aperture Radar (SAR) imaging is a traditional remote sensing tool, its adaptation to micro-UAV is an open issue and so far only few case studies concerning the integration of SAR and UAV technologies have been reported worldwide [2]. In addition, only early results concerning subsurface imaging by means of an UAV-mounted radar are available [3]. As a contribution to radar imaging via autonomous micro-UAV, this communication presents a proof-of-concept experiment. This experiment represents the first step towards the development of a general methodological approach that exploits expertise about (sub-)surface imaging and aerospace systems with the aim to provide high-resolution images of the surveyed scene. In details, at the conference, we will present the results of a flight campaign carried out by using a single radar

  15. Efficient active depth sensing by laser speckle projection system

    Science.gov (United States)

    Yin, Xuanwu; Wang, Guijin; Shi, Chenbo; Liao, Qingmin

    2014-01-01

    An active depth sensing approach by laser speckle projection system is proposed. After capturing the speckle pattern with an infrared digital camera, we extract the pure speckle pattern using a direct-global separation method. Then the pure speckles are represented by Census binary features. By evaluating the matching cost and uniqueness between the real-time image and the reference image, robust correspondences are selected as support points. After that, we build a disparity grid and propose a generative graphical model to compute disparities. An iterative approach is designed to propagate the messages between blocks and update the model. Finally, a dense depth map can be obtained by subpixel interpolation and transformation. The experimental evaluations demonstrate the effectiveness and efficiency of our approach.

  16. A Tagless Indoor Localization System Based on Capacitive Sensing Technology

    Directory of Open Access Journals (Sweden)

    Alireza Ramezani Akhmareh

    2016-09-01

    Full Text Available Accurate indoor person localization is essential for several services, such as assisted living. We introduce a tagless indoor person localization system based on capacitive sensing and localization algorithms that can determine the location with less than 0.2 m average error in a 3 m × 3 m room and has recall and precision better than 70%. We also discuss the effects of various noise types on the measurements and ways to reduce them using filters suitable for on-sensor implementation to lower communication energy consumption. We also compare the performance of several standard localization algorithms in terms of localization error, recall, precision, and accuracy of detection of the movement trajectory.

  17. Development of five port reflectometer for reflection based sensing system

    Science.gov (United States)

    Baharuddin, S. A.; Cheng, E. M.; Lee, K. Y.; Zaaba, S. K.; Syahirah, K. N.; Abbas, Z.; Nasir, N. F. Mohd; Afendi, M.; Zakaria, Z.

    2017-03-01

    Five-Port Reflectometer is a microwave passivedevice where it implements the six-port algorithm to measure the complex reflection coefficient of material under test (MUT) through reflection on interface between MUT and microwave sensor. Initially, the Six-Port Reflectometer (SPR) was introduced by Engen in 1977 and major component used insix-port technique was designed in many types. When Riblet and Hanssonproposed ring junction with 5 ports only on 1981. Six ports ring junction has been reduced to five ports. In this paper, a dual frequency five ports ring junction circuit was designed, simulated and fabricated for reflection based sensing system. The fabricated five port ring junction is operating at frequencies of 0.64 GHz and 2.42 GHz. The measured result had good agreement with the simulated results for dual frequencies in terms of magnitude and phase.

  18. Carbon nanotube based NEMS actuators and sensors

    Science.gov (United States)

    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.

  19. Engineered nanowires, carbon nanotubes and graphene for sensors, actuators and electronics

    Science.gov (United States)

    Yang, E. H.

    2010-02-01

    We are exploring nanoelectronic engineering areas based on low dimensional materials, including carbon nanotubes and graphene. Our primary research focus is investigating carbon nanotube and graphene architectures for field emission applications, energy harvesting and sensing. In a second effort, we are developing a high-throughput desktop nanolithography process. Lastly, we are studying nanomechanical actuators and associated nanoscale measurement techniques for re-configurable arrayed nanostructures with applications in antennas, remote detectors and biomedical nanorobots. The devices we fabricate, assemble, manipulate and characterize potentially have a wide range of applications including sensors, detectors, system-on-a-chip, system-in-a-package, programmable logic controls, energy storage systems and allelectronic systems.

  20. A portable fluorescent sensing system using multiple LEDs

    Science.gov (United States)

    Shin, Young-Ho; Barnett, Jonathan Z.; Gutierrez-Wing, M. Teresa; Rusch, Kelly A.; Choi, Jin-Woo

    2017-02-01

    This paper presents a portable fluorescent sensing system that utilizes different light emitting diode (LED) excitation lights for multiple target detection. In order to identify different analytes, three different wavelengths (385 nm, 448 nm, and 590 nm) of excitation light emitting diodes were used to selectively stimulate the target analytes. A highly sensitive silicon photomultiplier (SiPM) was used to detect corresponding fluorescent signals from each analyte. Based on the unique fluorescent response of each analyte, it is possible to simultaneously differentiate one analyte from the other in a mixture of target analytes. A portable system was designed and fabricated consisting of a display module, battery, data storage card, and sample loading tray into a compact 3D-printed jig. The portable sensor system was demonstrated for quantification and differentiation of microalgae (Chlorella vulgaris) and cyanobacteria (Spirulina) by measuring fluorescent responses of chlorophyll a in microalgae and phycocyanin in cyanobacteria. Obtained results suggest that the developed portable sensor system could be used as a generic fluorescence sensor platform for on-site detection of multiple analytes of interest.

  1. CMOS Conductometric System for Growth Monitoring and Sensing of Bacteria.

    Science.gov (United States)

    Lei Yao; Lamarche, P; Tawil, N; Khan, R; Aliakbar, A M; Hassan, M H; Chodavarapu, V P; Mandeville, R

    2011-06-01

    We present the design and implementation of a prototype complementary metal-oxide semiconductor (CMOS) conductometric integrated circuit (IC) for colony growth monitoring and specific sensing of Escherichia coli (E. coli) bacteria. The detection of E. coli is done by employing T4 bacteriophages as receptor organisms. The conductometric system operates by measuring the resistance of the test sample between the electrodes of a two-electrode electrochemical system (reference electrode and working electrode). The CMOS IC is fabricated in a TSMC 0.35-μm process and uses a current-to-frequency (I to F) conversion circuit to convert the test sample resistance into a digital output modulated in frequency. Pulsewidth control (one-shot circuit) is implemented on-chip to control the pulsewidth of the output digital signal. The novelty in the current work lies in the ability of the CMOS sensor system to monitor very low initial concentrations of bacteria (4×10(2) to 4×10(4) colony forming unit (CFU)/mL). The CMOS system is also used to record the interaction between E. coli and its specific receptor T4 bacteriophage. The prototype CMOS IC consumes an average power of 1.85 mW with a 3.3-V dc power supply.

  2. A Remote-Sensing-Driven System for Mining Marine Spatiotemporal Association Patterns

    OpenAIRE

    Cunjin Xue; Qing Dong; Xiaohong Li; Xing Fan; Yilong Li; Shuchao Wu

    2015-01-01

    Remote sensing is widely used to analyze marine environments. While many effective and advanced methods have been developed, they are generally used independently of each other, despite the potential advantages of combining different modules into an integrated system. We develop here an image-driven remote-sensing mining system, RSMapMining (Remote Sensing driven Marine spatiotemporal Association Pattern Mining system), which consists of three modules. The image preprocessing module integrate...

  3. Vibrations of double-nanotube systems with mislocation via a newly developed van der Waals model

    Science.gov (United States)

    Kiani, Keivan

    2015-06-01

    This study deals with transverse vibrations of two adjacent-parallel-mislocated single-walled carbon nanotubes (SWCNTs) under various end conditions. These tubes interact with each other and their surrounding medium through the intertube van der Waals (vdW) forces, and existing bonds between their atoms and those of the elastic medium. The elastic energy of such forces due to the deflections of nanotubes is appropriately modeled by defining a vdW force density function. In the previous works, vdW forces between two identical tubes were idealized by a uniform form of this function. The newly introduced function enables us to investigate the influences of both intertube free distance and longitudinal mislocation on the natural transverse frequencies of the nanosystem which consists of two dissimilar tubes. Such crucial issues have not been addressed yet, even for simply supported tubes. Using nonlocal Timoshenko and higher-order beam theories as well as Hamilton's principle, the strong form of the equations of motion is established. Seeking for an explicit solution to these integro-partial differential equations is a very problematic task. Thereby, an energy-based method in conjunction with an efficient meshfree method is proposed and the nonlocal frequencies of the elastically embedded nanosystem are determined. For simply supported nanosystems, the predicted first five frequencies of the proposed model are checked with those of assumed mode method, and a reasonably good agreement is achieved. Through various studies, the roles of the tube's length ratio, intertube free space, mislocation, small-scale effect, slenderness ratio, radius of SWCNTs, and elastic constants of the elastic matrix on the natural frequencies of the nanosystem with various end conditions are explained. The limitations of the nonlocal Timoshenko beam theory are also addressed. This work can be considered as a vital step towards better realizing of a more complex system that consists of

  4. A high throughput geocomputing system for remote sensing quantitative retrieval and a case study

    Science.gov (United States)

    Xue, Yong; Chen, Ziqiang; Xu, Hui; Ai, Jianwen; Jiang, Shuzheng; Li, Yingjie; Wang, Ying; Guang, Jie; Mei, Linlu; Jiao, Xijuan; He, Xingwei; Hou, Tingting

    2011-12-01

    The quality and accuracy of remote sensing instruments have been improved significantly, however, rapid processing of large-scale remote sensing data becomes the bottleneck for remote sensing quantitative retrieval applications. The remote sensing quantitative retrieval is a data-intensive computation application, which is one of the research issues of high throughput computation. The remote sensing quantitative retrieval Grid workflow is a high-level core component of remote sensing Grid, which is used to support the modeling, reconstruction and implementation of large-scale complex applications of remote sensing science. In this paper, we intend to study middleware components of the remote sensing Grid - the dynamic Grid workflow based on the remote sensing quantitative retrieval application on Grid platform. We designed a novel architecture for the remote sensing Grid workflow. According to this architecture, we constructed the Remote Sensing Information Service Grid Node (RSSN) with Condor. We developed a graphic user interface (GUI) tools to compose remote sensing processing Grid workflows, and took the aerosol optical depth (AOD) retrieval as an example. The case study showed that significant improvement in the system performance could be achieved with this implementation. The results also give a perspective on the potential of applying Grid workflow practices to remote sensing quantitative retrieval problems using commodity class PCs.

  5. Linearized augmented-plane-wave method for quasi-unidimensional systems: Carbyne and nanotube (Sc@C{sub 20})

    Energy Technology Data Exchange (ETDEWEB)

    D`yachkov, P.N. [Kurnakov Institute of General and Inorganic Chemistry, Moscow (Russian Federation); Nikolaev, A.V. [Institute of Physcial Chemistry, Moscow (Russian Federation)

    1995-10-01

    The advent of carbon nanotubes, which are graphite layers convoluted in cylinders several nanometers in diameter and several micrometers in length, as well as the experiments on implanting metal atoms in such tubes open the way to producing nanoconductors and other materials with unique properties. For theorists, the basic challenge is interpreting and predicting the structure and properties of these systems. The linearized augmented-plane-wave method (LAPW) is one of the most accurate methods in the theory of the electronic structure of solids. A generalization of this method for quasi-two-dimensional systems, surface electronic states, and layered crystals is known. The LAPW theory for quasi-unidimensional systems, which exhibit translational symmetry in one direction, has been absent thus far. In this paper, the authors suggest a version of such a theory and use this method to calculate the electronic structure of carbyne (a linear chain of carbon atoms) and carbon nanotube with implanted Sc atoms.

  6. Density control and wettability enhancement by functionalizing carbon nanotubes with nickel oxide in aluminum-carbon nanotube system.

    Science.gov (United States)

    Kim, Tae-Hoon; Park, Min-Ho; Song, Kwan-Woo; Bae, Jee-Hwan; Lee, Jae-Wook; Lee, Choong Do; Yang, Cheol-Woong

    2013-11-01

    Excellent mechanical properties of carbon nanotubes (CNTs) make them ideal reinforcements for synthesizing light weight, high strength metal matrix composite. Aluminum is attractive matrix due to its light weight and Al/CNT composites are promising materials for various industrial applications. Powder metallurgy and casting techniques are normally used for bulk fabrications of composites. Casting process which can mass-produce delicate product is more suitable than existing powder metallurgy in view point of application in industries. In CNT-metal matrix composites, however, composite bulk fabrication has been limited because of the large density gap and poor wettability between the metal and CNTs. This study suggests a method for alleviating such problems. It was found that the wettability between aluminum and CNT could be enhanced by functionalizing the CNTs with nickel oxide. This functionalization of CNTs with heavier element also reduces the density gap between the matrix and reinforcements. It is suggested that this method could possibly be used in a casting process to enable mass fabrication of CNT-metal matrix composites.

  7. Bragg grating structural sensing system for bridge monitoring

    Science.gov (United States)

    Measures, Raymond M.; Alavie, A. Tino; Maaskant, Robert; Ohn, Myo M.; Karr, Shawn E.; Huang, Shang Yuan

    1994-09-01

    Corrosion of steel within bridges and other large concrete structures has become a serious problem and consequently there is growing interest in replacing the steel within such structures with carbon fiber based composite materials. The first highway bridge in the world to use carbon fiber composite prestressing tendons was constructed and opened to the public in the fall of 1993. This two span bridge was also unique in another respect, it is the first highway bridge in the world to have been built with a set of fiber optic Bragg grating sensors structurally integrated into several of its precast concrete deck support girders. A four-channel fiber laser sensor demodulation system that was rugged, compact and transportable was developed for this project. This demodulation system monitored the changes in the internal strain on all three types (steel and two types of carbon fiber composite) of prestressing tendons over several months. The same structurally integrated fiber optic sensing system has also been used to measure the change in the internal strain within the deck girders arising from both static and dynamic loading of the bridge with a large truck.

  8. Smart Sensing System for the Prognostic Monitoring of Bone Health

    KAUST Repository

    Afsarimanesh, Nasrin

    2016-06-24

    The objective of this paper is to report a novel non-invasive, real-time, and label-free smart assay technique for the prognostic detection of bone loss by electrochemical impedance spectroscopy (EIS). The proposed system incorporated an antibody-antigen-based sensor functionalization to induce selectivity for the C-terminal telopeptide type one collagen (CTx-I) molecules—a bone loss biomarker. Streptavidin agarose was immobilized on the sensing area of a silicon substrate-based planar sensor, patterned with gold interdigital electrodes, to capture the antibody-antigen complex. Calibration experiments were conducted with various known CTx-I concentrations in a buffer solution to obtain a reference curve that was used to quantify the concentration of an analyte in the unknown serum samples. Multivariate chemometric analyses were done to determine the performance viability of the developed system. The analyses suggested that a frequency of 710 Hz is the most discriminating regarding the system sensitivity. A detection limit of 0.147 ng/mL was achieved for the proposed sensor and the corresponding reference curve was linear in the range of 0.147 ng/mL to 2.669 ng/mL. Two sheep blood samples were tested by the developed technique and the results were validated using enzyme-linked immunosorbent assay (ELISA). The results from the proposed technique match those from the ELISA.

  9. When carbon nanotubes encounter the immune system: desirable and undesirable effects.

    Science.gov (United States)

    Dumortier, Hélène

    2013-12-01

    The role of our immune system is to bring efficient protection against invasion by foreign elements, not only pathogens but also any material it may be in contact with. Nanoparticles may enter the body and encounter the immune system either intentionally (e.g. administration for biomedical application) or not (e.g. respiratory occupational exposure). Therefore, it is of fundamental importance to get a thorough knowledge of the way they interact with immune cells and all related consequences. Among nanomaterials, carbon nanotubes (CNTs) are of special interest because of their tremendous field of applications. Consequently, their increasing production, processing and eventual incorporation into new types of composites and/or into biological systems have raised fundamental issues regarding their potential impact on health. This review aims at giving an overview of the known desirable and undesirable effects of CNTs on the immune system, i.e. beneficial modulation of immune cells by CNTs engineered for biomedical applications versus toxicity, inflammation and unwanted immune reactions triggered by CNTs themselves.

  10. Orthodontic tunnel miniscrews with and without TiO2 nanotube arrays as a drug-delivery system: In vivo study.

    Science.gov (United States)

    Cha, Bong-Kuen; Choi, Dong-Soon; Jang, Insan; Choe, Byung-Hak; Choi, Won-Youl

    2016-09-28

    Orthodontic tunnel miniscrews with and without TiO2 nanotube arrays were fabricated to improve the induction of new bone formation and osseointegration. To inject the drug of recombinant human bone morphogenetic protein, tunnels in a conventional machined miniscrew were machined by a computer-numerical-control lathe. TiO2 nanotube arrays to load the drug were also formed on the surface of the tunnel miniscrew by anodic oxidation. To obtain clean TiO2 nanotube arrays, two-step anodic oxidation was conducted. The diameters of TiO2 nanotube window and TiO2 nanotube were ∼70 nm and ∼110 nm, respectively. Three groups, i.e., a conventional machined miniscrew, a tunnel miniscrew without TiO2 nanotube arrays, and a tunnel miniscrew with TiO2 nanotube arrays, were prepared and inserted in the legs of five New Zealand White rabbits. In a histomorphometric analysis, the bone implant contact ratios of the tunnel miniscrews with the TiO2 nanotube arrays and without the TiO2 nanotube arrays were 5.84% and 5.88%, respectively. These values were higher than the value of 4.30% for the conventional machined miniscrew. The bone surface ratios in the tunnel miniscrew with and without the TiO2 nanotube were also higher than those of the conventional machined miniscrew. The measured values of the tunnel miniscrew with and without the nanotube and the conventional miniscrew were 76.75%, 73.41%, and 44.82%, respectively, although the differences were statistically insignificant. New bone at three weeks and six weeks after the operations were found in the tunnel miniscrews in fluorescent images. Both the tunnel miniscrews with and without the TiO2 nanotube arrays demonstrated greater bone formation compared to the conventional miniscrews. However, TiO2 nanotube arrays was not likely to provide additional benefit to the tunnel miniscrew. An in vivo study suggested that the tunnel fabricated in the miniscrew can be efficient drug-delivery systems to improve osseointegration.

  11. Modeling of Electronic Transport in Scanning Tunneling Microscope Tip-Carbon Nanotube Systems

    Science.gov (United States)

    Yamada, Toshishige; Kwak, Dochan (Technical Monitor)

    2000-01-01

    A model is proposed for two observed current-voltage (I-V) patterns in a recent experiment with a scanning tunneling microscope tip and a carbon nanotube. We claim that there are two mechanical contact modes for a tip (metal) -nanotube (semiconductor) junction (1) with or (2) without a tiny vacuum gap (0.1 - 0.2 nm). With the tip grounded, the tunneling case in (1) would produce large dI/dV with V > 0, small dI/dV with V < 0, and I = 0 near V = 0 for an either n- or p-nanotube; the Schottky mechanism in (2) would result in I does not equal 0 only with V < 0 for an n-nanotube, and the bias polarities would be reversed for a p-nanotube. The two observed I-V patterns are thus entirely explained by a tip-nanotube contact of the two types, where the nanotube must be n-type.

  12. A Review: Carbon Nanotube-Based Piezoresistive Strain Sensors

    Directory of Open Access Journals (Sweden)

    Waris Obitayo

    2012-01-01

    Full Text Available The use of carbon nanotubes for piezoresistive strain sensors has acquired significant attention due to its unique electromechanical properties. In this comprehensive review paper, we discussed some important aspects of carbon nanotubes for strain sensing at both the nanoscale and macroscale. Carbon nanotubes undergo changes in their band structures when subjected to mechanical deformations. This phenomenon makes them applicable for strain sensing applications. This paper signifies the type of carbon nanotubes best suitable for piezoresistive strain sensors. The electrical resistivities of carbon nanotube thin film increase linearly with strain, making it an ideal material for a piezoresistive strain sensor. Carbon nanotube composite films, which are usually fabricated by mixing small amounts of single-walled or multiwalled carbon nanotubes with selected polymers, have shown promising characteristics of piezoresistive strain sensors. Studies also show that carbon nanotubes display a stable and predictable voltage response as a function of temperature.

  13. The electrochemistry of carbon nanotubes: fundamentals and applications.

    Science.gov (United States)

    Pumera, Martin

    2009-01-01

    Carbon nanotubes (CNTs) are in the forefront of electrochemical research. It has become clear that an understanding of the fundamental reasons for the electrochemical activity of CNTs is essential for further progress in the field. This review provides a critical discussion of the fundamental reasons behind the electrochemical and "electrocatalytic" activity of CNTs as well as on important applications of CNTs for sensing, biosensing, and energy storage systems.

  14. Environmental Sensing of Aquatic Systems at the University of Geneva.

    Science.gov (United States)

    Bakker, Eric; Tercier-Waeber, Mary-Lou; Cherubini, Thomas; Crespi, Miquel Coll; Crespo, Gastón A; Cuartero, Maria; Afshar, Majid Ghahraman; Jarolimova, Zdenka; Jeanneret, Stéphane; Mongin, Sandrine; Néel, Bastien; Pankratova, Nadezda; Touilloux, Romain; Xie, Xiaojiang; Zhai, Jingying

    2014-11-01

    Aquatic environments are complex living systems where biological and chemical constituents change rapidly with time and space and may exhibit synergistic interactions. To understand these processes, the traditional approach based on a typically monthly collection of samples followed by laboratory analysis is not adequate. It must be replaced by high-resolution autonomous in situ detection approaches. In our group at the University of Geneva, we aim to develop and deploy chemical sensor probes to understand complex aquatic systems. Most research centers around electrochemical sensing approaches, which involves: stripping voltammetry at gel-coated microelectrode arrays for direct measurements of bioavailable essential or toxic trace metals; direct potentiometry for the measurement of nutrients and other species involved in the nitrogen and carbon cycles; online desalination for oceanic measurements; the development of robust measurement principles such as thin layer coulometry, and speciation analysis by tandem electrochemical detection with potentiometry and dynamic electrochemistry. These fundamental developments are combined with instrument design, both in-house and with external partners, and result in field deployments in partnership with environmental researchers in Switzerland and the European Union.

  15. Non-covalently Functionalized Fluorescent Carbon Nanotubes: A Supramolecular Approach of Selective Zinc Ions Sensing in Living Cells%Non-covalently Functionalized Fluorescent Carbon Nanotubes: A Supramolecular Approach of Selective Zinc Ions Sensing in Living Cells

    Institute of Scientific and Technical Information of China (English)

    刘玉萍; 陈湧; 张宁; 刘育

    2012-01-01

    A fluorescent cyclodextrin/carbon nanotube assembly was easily constructed through the non-covalent attach- ment of adamantanylpyrene on carbon nanotube and the following association of cyclodextrin derivative bearing fluorescent substituent, and its structure was fully characterized by UV/Vis/NIR spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and atomic force microscopy. Fluorescence spectroscopic and fluorescence microscopic studies showed that the resultant non-covalently functionalized fluo- rescent nanotube could be used as a highly selective fluorescent probe for Zn2+ in both water and living cells. Without carbon nanotube, the fluorescence probe was unable to enter the cell but only anchored on the cell mem- brane. This approach will overcome the disadvantage of many spectral sensors that are unable to enter living cells and greatly improve the application of naotube-related supramolecular architecture in nanoscience and technology.

  16. Multifunctional Nanotube Polymer Nanocomposites for Aerospace Applications: Adhesion between SWCNT and Polymer Matrix

    Science.gov (United States)

    Park, Cheol; Wise, Kristopher E.; Kang, Jin Ho; Kim, Jae-Woo; Sauti, Godfrey; Lowther, Sharon E.; Lillehei, Peter T.; Smith, Michael W.; Siochi, Emilie J.; Harrison, Joycelyn S.; Jordan, Kevin

    2008-01-01

    Multifunctional structural materials can enable a novel design space for advanced aerospace structures. A promising route to multifunctionality is the use of nanotubes possessing the desired combination of properties to enhance the characteristics of structural polymers. Recent nanotube-polymer nanocomposite studies have revealed that these materials have the potential to provide structural integrity as well as sensing and/or actuation capabilities. Judicious selection or modification of the polymer matrix to promote donor acceptor and/or dispersion interactions can improve adhesion at the interface between the nanotubes and the polymer matrix significantly. The effect of nanotube incorporation on the modulus and toughness of the polymer matrix will be presented. Very small loadings of single wall nanotubes in a polyimide matrix yield an effective sensor material that responds to strain, stress, pressure, and temperature. These materials also exhibit significant actuation in response to applied electric fields. The objective of this work is to demonstrate that physical properties of multifunctional material systems can be tailored for specific applications by controlling nanotube treatment (different types of nanotubes), concentration, and degree of alignment.

  17. Fostering a regional vision on river systems by remote sensing

    Science.gov (United States)

    Bizzi, S.; Piegay, H.; Demarchi, L.

    2015-12-01

    River classification and the derived knowledge about river systems have been relying until recently on discontinuous field campaigns and visual interpretation of aerial images. For this reason, building a regional vision on river systems based on a systematic and coherent set of hydromorphological indicators was, and still is, a research challenge. Remote sensing data, since some years, offer notable opportunities to shift this paradigm offering an unprecedented amount of spatially distributed data over large scales, such as regional. Here, we have implemented a river characterization framework based on color infrared orthophotos at 40 cm and a LIDAR derived DTM at 5 m acquired simultaneously in 2009-2010 for all Piedmont Region Italy (25400 kmq). 1500 km of river systems have been characterized in terms typology, geometry and topography of hydromorphological features. The framework delineates the valley bottom of each river course, and maps by a semi-automated procedure water channels, unvegetated and vegetated sediment bars, islands, and riparian corridors. Using a range of statistical techniques the river systems have been segmented and classified with an objective, quantitative, and then repeatable approach. Such regional database enhances our ability to address a number of research and management challenges, such as: i) quantify shape and topography of channel forms for different river functional types, and investigate their relationships with potential drivers like hydrology, geology, land use and historical contingency; ii) localize most degraded and better functioning river stretches so to prioritize finer scale monitoring and set quantifiable restoration targets; iii) provide indication for future RS acquisition campaigns so to start monitoring river processes at the regional scale. The Piedmont Region in Italy is here used as a laboratory of concrete examples and analyses to discuss our current ability to answer to these challenges in river science.

  18. Monte Carlo simulation of a compact microbeam radiotherapy system based on carbon nanotube field emission technology.

    Science.gov (United States)

    Schreiber, Eric C; Chang, Sha X

    2012-08-01

    Microbeam radiation therapy (MRT) is an experimental radiotherapy technique that has shown potent antitumor effects with minimal damage to normal tissue in animal studies. This unique form of radiation is currently only produced in a few large synchrotron accelerator research facilities in the world. To promote widespread translational research on this promising treatment technology we have proposed and are in the initial development stages of a compact MRT system that is based on carbon nanotube field emission x-ray technology. We report on a Monte Carlo based feasibility study of the compact MRT system design. Monte Carlo calculations were performed using EGSnrc-based codes. The proposed small animal research MRT device design includes carbon nanotube cathodes shaped to match the corresponding MRT collimator apertures, a common reflection anode with filter, and a MRT collimator. Each collimator aperture is sized to deliver a beam width ranging from 30 to 200 μm at 18.6 cm source-to-axis distance. Design parameters studied with Monte Carlo include electron energy, cathode design, anode angle, filtration, and collimator design. Calculations were performed for single and multibeam configurations. Increasing the energy from 100 kVp to 160 kVp increased the photon fluence through the collimator by a factor of 1.7. Both energies produced a largely uniform fluence along the long dimension of the microbeam, with 5% decreases in intensity near the edges. The isocentric dose rate for 160 kVp was calculated to be 700 Gy∕min∕A in the center of a 3 cm diameter target. Scatter contributions resulting from collimator size were found to produce only small (<7%) changes in the dose rate for field widths greater than 50 μm. Dose vs depth was weakly dependent on filtration material. The peak-to-valley ratio varied from 10 to 100 as the separation between adjacent microbeams varies from 150 to 1000 μm. Monte Carlo simulations demonstrate that the proposed compact MRT system

  19. Calibration and deployment of a fiber-optic sensing system for monitoring debris flows.

    Science.gov (United States)

    Huang, Ching-Jer; Chu, Chung-Ray; Tien, Tsung-Mo; Yin, Hsiao-Yuen; Chen, Ping-Sen

    2012-01-01

    This work presents a novel fiber-optic sensing system, capable of monitoring debris flows or other natural hazards that produce ground vibrations. The proposed sensing system comprises a demodulator (BraggSCOPE, FS5500), which includes a broadband light source and a data logger, a four-port coupler and four Fiber Bragg Grating (FBG) accelerometers. Based on field tests, the performance of the proposed fiber-optic sensing system is compared with that of a conventional sensing system that includes a geophone or a microphone. Following confirmation of the reliability of the proposed sensing system, the fiber-optic sensing systems are deployed along the Ai-Yu-Zi and Chu-Shui Creeks in Nautou County of central Taiwan for monitoring debris flows. Sensitivity test of the deployed fiber-optic sensing system along the creek banks is also performed. Analysis results of the seismic data recorded by the systems reveal in detail the frequency characteristics of the artificially generated ground vibrations. Results of this study demonstrate that the proposed fiber-optic sensing system is highly promising for use in monitoring natural disasters that generate ground vibrations.

  20. Development of fiber-optic current sensing technique and its applications in electric power systems

    Science.gov (United States)

    Kurosawa, Kiyoshi

    2014-03-01

    This paper describes the development and applications of a fiber-optic electric current sensing technique with the stable properties and compact, simple, and flexible structure of the sensing device. The special characteristics of the sensors were achieved by use of the special low birefringence fiber as the Faraday-effect sensing element and were also achieved with creation of sensing schemes which matched with the features of the fiber. Making use of the excellent features of the sensing technique, various current monitoring devices and systems were developed and applied practically for the control and maintenance in the electric power facility. In this paper, the design and performance of the sensing devices are introduced first. After that, examples of the application systems practically applied are also introduced, including fault section/point location systems for power transmission cable lines.

  1. Weighing a single atom using a coupled plasmon–carbon nanotube system

    Directory of Open Access Journals (Sweden)

    Jin-Jin Li and Ka-Di Zhu

    2012-01-01

    Full Text Available We propose an optical weighing technique with a sensitivity down to a single atom, using a surface plasmon and a doubly clamped carbon nanotube resonator. The mass of a single atom is determined via the vibrational frequency shift of the carbon nanotube while the atom attaches to the nanotube surface. Owing to the ultralight mass and high quality factor of the carbon nanotube, and the spectral enhancement by the use of surface plasmon, this method results in a narrow linewidth (kHz and high sensitivity (2.3×10−28 Hzcenterdot g−1, which is five orders of magnitude more sensitive than traditional electrical mass detection techniques.

  2. Geographic Information System and Remote Sensing in Disaster Management

    Directory of Open Access Journals (Sweden)

    Deniz Arca

    2012-12-01

    Full Text Available While our country is a sources of unique beauties in various fields such as natural beauty, history, culture, art, climatic features, geographical position, it is also a country of catastrophe. It is especially a country of earthquake which often experiences forceful earthquakes.Catastrophe, earthquake in particular, is a reality we should admit and learn to live with. Therefore, we are responsible to minimize the loss and damage stemming from catastrophe in our era when it is still impossible to determine catastrophe in advance. The loss can be minimized by working and measurements which should be taken before, during and after the catastrophe. In this context, Geographical Information System and remote sensing has much importance.The primary mission of the Disaster Management is, therefore, to reduce the loss of life and property and protect the nations from all hazards, including natural disasters, acts of terrorism, and other man-made disasters, by leading and supporting the nations in a risk-based, comprehensive emergency management system of preparedness, protection, response, recovery, and mitigation. Recently, disaster management emphasizes the importance of disaster prevention - focusing on disaster preparedness.The studies regarding natural hazards RS and GIS are widely used today. These studies include earthquake, flood, landslide, fire, volcanic eruptions, storm and other natural phenomena that cause natural disasters. GIS and RS are not only used for locating, monitoring and determining influence areas of these natural events, but are very useful in determining what is to be done before and after a natural disaster. Effective usage of GIS technologies regarding disasters first depends on determining that for what purpose and how they are going to be used. In this respect, it is a necessity to explain of how an effective and contemporary disaster management system and its components should be before dealing with the characteristics

  3. Multibeam monopulse radar for airborne sense and avoid system

    Science.gov (United States)

    Gorwara, Ashok; Molchanov, Pavlo

    2016-10-01

    The multibeam monopulse radar for Airborne Based Sense and Avoid (ABSAA) system concept is the next step in the development of passive monopulse direction finder proposed by Stephen E. Lipsky in the 80s. In the proposed system the multibeam monopulse radar with an array of directional antennas is positioned on a small aircaraft or Unmanned Aircraft System (UAS). Radar signals are simultaneously transmitted and received by multiple angle shifted directional antennas with overlapping antenna patterns and the entire sky, 360° for both horizontal and vertical coverage. Digitizing of amplitude and phase of signals in separate directional antennas relative to reference signals provides high-accuracy high-resolution range and azimuth measurement and allows to record real time amplitude and phase of reflected from non-cooperative aircraft signals. High resolution range and azimuth measurement provides minimal tracking errors in both position and velocity of non-cooperative aircraft and determined by sampling frequency of the digitizer. High speed sampling with high-accuracy processor clock provides high resolution phase/time domain measurement even for directional antennas with wide Field of View (FOV). Fourier transform (frequency domain processing) of received radar signals provides signatures and dramatically increases probability of detection for non-cooperative aircraft. Steering of transmitting power and integration, correlation period of received reflected signals for separate antennas (directions) allows dramatically decreased ground clutter for low altitude flights. An open architecture, modular construction allows the combination of a radar sensor with Automatic Dependent Surveillance - Broadcast (ADS-B), electro-optic, acoustic sensors.

  4. A role for AVIRIS in the Landsat and Advanced Land Remote Sensing Systems program

    Science.gov (United States)

    Green, Robert O.; Simmonds, John J.

    1993-01-01

    As a calibrated imaging spectrometer flying at a 20 km altitude, AVIRIS may contribute to the Landsat and the Advanced Land Remote Sensing System efforts. These contributions come in the areas of: (1) on-orbit calibration, (2) specification of new spectral bands, (3) validation of algorithms, and (4) investigation of an imaging spectrometer of the Advanced Land Remote Sensing System.

  5. The Toxicology of Carbon Nanotubes

    Science.gov (United States)

    Donaldson, Ken; Poland, Craig; Duffin, Rodger; Bonner, James

    2012-06-01

    1. Carbon nanotube structure, synthesis and applications C. Singh and W. Song; 2. The aerodynamic behaviour and pulmonary deposition of carbon nanotubes A. Buckley, R. Smith and R Maynard; 3. Utilising the concept of the biologically effective dose to define the particle and fibre hazards of carbon nanotubes K. Donaldson, R. Duffin, F. Murphy and C. Poland; 4. CNT, biopersistence and the fibre paradigm D. Warheit and M. DeLorme; 5. Length-dependent retention of fibres in the pleural space C. Poland, F. Murphy and K. Donaldson; 6. Experimental carcinogenicity of carbon nanotubes in the context of other fibres K. Unfried; 7. Fate and effects of carbon nanotubes following inhalation J. Ryman-Rasmussen, M. Andersen and J. Bonner; 8. Responses to pulmonary exposure to carbon nanotubes V. Castranova and R. Mercer; 9. Genotoxicity of carbon nanotubes R. Schins, C. Albrecht, K. Gerloff and D. van Berlo; 10. Carbon nanotube-cellular interactions; macrophages, epithelial and mesothelial cells V. Stone, M. Boyles, A. Kermanizadeh, J. Varet and H. Johnston; 11. Systemic health effects of carbon nanotubes following inhalation J. McDonald; 12. Dosimetry and metrology of carbon nanotubes L. Tran, L. MacCalman and R. Aitken; Index.

  6. Ternary hybrid systems of P3HT-CdSe-WS₂ nanotubes for photovoltaic applications.

    Science.gov (United States)

    Bruno, A; Borriello, C; Haque, S A; Minarini, C; Di Luccio, T

    2014-09-07

    Hybrid heterojunctions of conjugated polymers and inorganic nanomaterials are a promising combination for obtaining high performance solar cells (SC). In this work we have explored new possible uses of the WS2 nanotubes (NTs) both as the only acceptor material blended with a polymer and in ternary systems mixed with a polymer and quantum dots (QDs). In particular we have spectroscopically investigated binary blends of poly(3-hexylthiophene) (P3HT) and WS2 NTs, P3HT and CdSe QDs, and ternary blends of P3HT, CdSe QDs and WS2 NTs. We report fluorescence quenching effects of the QD signal in the P3HT-CdSe-WS2 system with the increase of NT concentration. Static and time-resolved fluorescence studies reveal efficient resonant energy transfer from the QDs to the NTs upon photoexcitation. The evidence of energetic interaction between WS2 NTs and QDs opens new fields of application of WS2 NTs and holds very promising potential for improving charge transfer phenomena in the active layer of hybrid solar cells.

  7. On Sensor Data Verification for Participatory Sensing Systems

    Directory of Open Access Journals (Sweden)

    Diego Mendez

    2013-03-01

    Full Text Available In this paper we study the problem of sensor data verification in Participatory Sensing (PS systems using an air quality/pollution monitoring application as a validation example. Data verification, in the context of PS, consists of the process of detecting and removing spatial outliers to properly reconstruct the variables of interest. We propose, implement, and test a hybrid neighborhood-aware algorithm for outlier detection that considers the uneven spatial density of the users, the number of malicious users, the level of conspiracy, and the lack of accuracy and malfunctioning sensors. The algorithm utilizes the Delaunay triangulation and Gaussian Mixture Models to build neighborhoods based on the spatial and non-spatial attributes of each location. This neighborhood definition allows us to demonstrate thatit is not necessary to apply accurate but computationally expensive estimators to the entire dataset to obtain good results, as equally accurate but computationally cheaper methods can also be applied to part of the data and obtain good results as well. Our experimental results show that our hybrid algorithm performs as good as the best estimator while reducing the execution time considerably.

  8. Optical sensing systems based on biomolecular recognition of recombinant proteins

    Science.gov (United States)

    Salins, Lyndon L.; Schauer-Vukasinovic, Vesna; Daunert, Sylvia

    1998-05-01

    SIte-directed mutagenesis and the associated site-specific fluorescent labeling of proteins can be used to rationally design reagentless fluorescent molecular senors. The phosphate binding protein (PBP) and calmodulin (CaM) bind to phosphate and calcium in a highly specific manner. These ions induce a hinge motion in the proteins, and the resultant conformational change constitutes the basis of the sensor development. By labeling each protein at a specific site with environment-sensitive fluorescent probes, these conformational changes can be monitored and related to the amount of analyte ion present. In this study, the polymerase chain reaction was used to construct mutants of PBP and CaM that have a single cysteine at positions 197 and 109, respectively. Each protein was site-specifically labeled through the sulfhydryl group of the introduced cysteine residue at a single location with an environment-sensitive fluorescent probe. Characterization of the steady-state fluorescence indicated an enhancement of signal intensity upon binding of the analyte ion. Highly sensitive and selective and selective sensing systems for phosphate and calcium were obtained by using this approach.

  9. Jellyfish Patch Detecting Using Low Latitude Remote Sensing System

    Science.gov (United States)

    Lee, J. S.; Jo, Y. H.

    2015-12-01

    Jellyfish can be asexual and sexual reproduction depending on the environment, and it has excellent environmental adaptability and reproduction than other sea creatures. If the marine environment become worse, jellyfish can take advantage in the competition for survival. Marine environmental changes caused by rapid climate change, dyke construction and land reclamation will increase the amount of jellyfish and as a result can lead to a various social and economic problems. In this study, jellyfish were observed in coastal area using a low-altitude Helikite remote sensing system for the first time. Helikite is a type of helium balloon plus a kite that can get the data with optical sensors for the desired spatial resolutions by adjusting the altitudes. In addition, it has an advantage that can monitor any objects for a long time at one place as long as the electric power and helium last. In this study, we observed the jellyfish patches using a digital camera in the Chesapeake Bay and estimate populations and size of jellyfish patches through image processing. Research results suggests that we can have long-term real-time observations for not only jellyfish, but also other harmful marine creatures.

  10. Low-temperature electronic transport in one-dimensional hybrid systems: Metal cluster embedded carbon nanotubes

    Science.gov (United States)

    Soldano, Caterina

    The investigation of the electronic and magnetotransport properties at low temperature in individual MWNT with embedded clusters are here presented. The majority of studies of transport in MWNT reported in literature has been carried out on arc-discharge grown tubes, generally considered "clean" and defect-free. In this project, individual MWNT grown in alumina template are used; these tubes are highly disordered compared for example to arc-discharge ones, conditions that dramatically will impact the charge transport. As-fabricated devices are in general highly resistive. A large decrease in the value of the device resistance can be achieved through a controlled and fast high-bias sweep method (HBT) across the sample. Scanning electron microscopy analysis shows that this method induces a metal (platinum) decoration of the MWNT surface as a consequence of the large amount of Joule heating developed during the sweep. Temperature dependence study (5wires. DFT calculations show that the enhancement in conductance can be explained in term of enhanced density of states around the Fermi energy due to presence of platinum on the wall. Magneto-transport measurements carried out up to a value of magnetic field up to |5|T show a clear dependence from the energy (i.e. applied bias). A nearly symmetric and monotonically increasing positive magneto-conductance is observed in the range of the applied field, confirming the presence of weak localization in the system. A small but distinct Rashba spin-orbit scattering effect in the magneto-conductance in the low-field regime (|B|<.5T) is found and attributed to the surface decoration. Electronic and magnetotransport measurements independently confirm the 1D nature of the transport in the system. "Zero-field" measurements were performed on magnetic cluster-embedded MWNT-based devices (FM-MWNT). Temperature dependence of the conductance reveals a Luttinger liquid type of behavior in the range of investigated temperatures but no

  11. Flexible carbon nanotube nanocomposite sensor for multiple physiological parameter monitoring

    KAUST Repository

    Nag, Anindya

    2016-10-16

    The paper presents the design, development, and fabrication of a flexible and wearable sensor based on carbon nanotube nanocomposite for monitoring specific physiological parameters. Polydimethylsiloxane (PDMS) was used as the substrate with a thin layer of a nanocomposite comprising functionalized multi-walled carbon nanotubes (MWCNTs) and PDMS as electrodes. The sensor patch functionalized on strain-sensitive capacitive sensing from interdigitated electrodes which were patterned with a laser on the nanocomposite layer. The thickness of the electrode layer was optimized regarding strain and conductivity. The sensor patch was connected to a monitoring device from one end and attached to the body on the other for examining purposes. Experimental results show the capability of the sensor patch used to detect respiration and limb movements. This work is a stepping stone of the sensing system to be developed for multiple physiological parameters.

  12. Targeted therapy of SMMC-7721 liver cancer in vitro and in vivo with carbon nanotubes based drug delivery system.

    Science.gov (United States)

    Ji, Zongfei; Lin, Gaofeng; Lu, Qinghua; Meng, Lingjie; Shen, Xizhong; Dong, Ling; Fu, Chuanlong; Zhang, Xiaoke

    2012-01-01

    A new type of drug delivery system (DDS) involved chitosan (CHI) modified single walled carbon nanotubes (SWNTs) for controllable loading/release of anti-cancer doxorubicin (DOX) was constructed. CHI was non-covalently wrapped around SWNTs, imparting water-solubility and biocompatibility to the nanotubes. Folic acid (FA) was also bounded to the outer CHI layer to realize selective killing of tumor cells. The targeting DDS could effectively kill the HCC SMMC-7721 cell lines and depress the growth of liver cancer in nude mice, showing superior pharmaceutical efficiency to free DOX. The results of the blood routine and serum biochemical parameters, combined with the histological examinations of vital organs, demonstrating that the targeting DDS had negligible in vivo toxicity. Thus, this DDS is promising for high treatment efficacy and low side effects for future cancer therapy.

  13. Design of fibers spun from carbon nanotube-sphere binary colloidal systems as substrates for cell behaviour control

    Science.gov (United States)

    Polizu, Stefania

    The aim of this work is to design new carbon nanotube neural biomaterials shaped as fibers, where the biodegradability and biocompatibility are achieved. Capitalizing on wet spinning process, we propose a hybrid approach allowing the integration of carbon nanotubes (CNTs) in macroscopic fibers with biodegradable and biocompatible responses. This new fabrication method use the wet spinning process which eludes the CNT's covalent chemistry, thus preserving the intrinsic characteristics of nanotubes. Our concept is based on the development of a spinnable Nanotube-Sphere Binary Colloidal System (NSBCS) for a wet spinning process. It contains CNTs dispersed with sodium dodecyl sulphate (SDS) and an aqueous suspension of polylactic-co-glycolic acid (PLGA) nanoparticles combined in a variety of ratios. The efficiency of this method resides in the synergistic effect of spherical nanoparticles and rod-like particles assembled in a binary colloid system which plays a main role in the spinning process. The configuration of mixture dispersions at sub-microscopic and microscopic level is related to the spatial confinement created by the gaps between spherical particles. They ensure the insertion of nanotubes in the PLGA lattice and assist the formation of the fiber during the spinning process. A spatial confinement is induced through the insertion of nanotubes between the nanoparticles. It is further increased by the passage of the mixture from cylindrical syringe's needle to conical nozzle, during the injection of the mixture into the coagulation bath. At this stage of the process, the combination of the confinement effect with the shear flow action is advantageous. The method we propose promotes the spinning of CNT macroscopic fibers from a binary colloidal mixture containing CNTs combined with PLGA nanoparticles in a variety of ratios, thus resulting in fibers with various CNT content. PLGA spherical nanoparticles root the structuring of fibers, thus improving the

  14. Photocatalytic Activity of Titanate Nanotube Powders in a Hybrid Pollution Control System

    Directory of Open Access Journals (Sweden)

    Sun-Jae Kim

    2012-01-01

    Full Text Available The photocatalytic activity on decomposition of Rhodamine B (RB of titanate nanotubes (TNTs synthesized by alkali hydrothermal treatment method was evaluated using a microwave/UV/photocatalyst hybrid system. The effects of each element technique as well as the synergy effects on decomposition of organic material were investigated. When TNTs were ion-exchanged with HCl, Na+ content was reduced from 8.36 wt% to 0.03 wt%, whereas the TNTs calcined at 723 K was phase-transformed into anatase structure. The RB decomposition rate increased with TNTs dosage as well as with microwave intensity. Effect of addition of auxiliary oxidants on photocatalytic decomposition of RB was also investigated. When ozone was added, the decomposition rate increased with the amount of ozone added. When H2O2 was used as the auxiliary oxidant, however, addition of H2O2 exceeding a threshold amount caused reduction of decomposition rate. A synergy effect was observed when H2O2 addition was combined with microwave-assisted photocatalysis.

  15. ABTS-modified multiwalled carbon nanotubes as an effective mediating system for bioelectrocatalytic reduction of oxygen.

    Science.gov (United States)

    Karnicka, Katarzyna; Miecznikowski, Krzysztof; Kowalewska, Barbara; Skunik, Magdalena; Opallo, Marcin; Rogalski, Jerzy; Schuhmann, Wolfgang; Kulesza, Pawel J

    2008-10-01

    The ability of such a common redox mediator as 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) to undergo sorption on carbon surfaces is explored here to convert multiwalled carbon nanotubes (CNTs) into a stable colloidal solution of ABTS-modified carbon nanostructures, the diameters of which are approximately 10 nm (as determined by transmission electron microscopy). Subsequently, inks composed of fungal laccase (Cerrena unicolor) mixed with the dispersion of ABTS-modified CNTs and stabilized with Nafion, were deposited on glassy carbon and successfully employed to the reduction of oxygen in McIlvain buffer at pH 5.2. For comparison, the systems utilizing only ABTS-free CNTs and laccase as well as ABTS-modified CNTs did not show appreciable activity toward the oxygen reduction. The three-dimensionally distributed ABTS-modified CNTs are expected to improve the film's overall conductivity and to facilitate electrical connection between the electrode and the enzyme. The network film of ABTS-modified CNTs is rigid, and it is characterized by charge propagation capabilities comparable to the conventional redox polymers. The whole concept of utilization of CNTs modified with ultrathin films of redox mediators in the preparation of efficient bioelectrocatalytic films seems to be of general importance to electroanalytical chemistry and to the development of biosensors.

  16. DNA-wrapped Carbon nanotubes as a model rod-like colloid system

    Science.gov (United States)

    Zheng, Ming

    2013-03-01

    Single-wall carbon nanotubes (SWCNTs) exhibit many fascinating physical behavior as the result of their quasi one-dimensional crystalline structures. SWCNTs can be dispersed into rod-like colloid particles by a few small molecules and polymers, among which the most effect one is single-stranded DNA (Nature Materials 2, 338, 2003). The structure of a DNA-SWCNT hybrid is controlled by both the sequence of the wrapping DNA, and the atomic configuration, or chirality, of the SWCNT (Science 302, 1545, 2003). This has been exploited by us to purify single-chirality SWCNTs from synthetic mixtures via liquid chromatography (Nature 460, 250, 2009; JACS 133, 12998, 2011). DNA-SWCNTs have well-defined surface structures, tunable aspect-ratios, and ultra-small diameters. These attributes provide unique advantages to the DNA-SWCNT colloid system in probing inter-particle interactions in crowded and high salt environment (ACS Nano 5, 8258, 2011). In this talk, I will present some recent observations we made on DNA-SWCNT clustering that shed new light on the Hofmeister effect.

  17. Equipment and techniques for carbon nanotube research

    Energy Technology Data Exchange (ETDEWEB)

    Vorob' eva, Alla I [Belarusian State University of Informatics and Radioelectronics, Minsk (Belarus)

    2010-06-07

    Many nanotube applications, in particular those in nanoelectronic systems, require nanotubes with strictly defined electrophysical parameters. This paper reviews equipment and techniques for studying and measuring the most important of these parameters. Theoretical and experimental parameter values obtained from different techniques are compared. Ways of preparing nanotube-containing samples for investigation and measurement purposes are examined. (instruments and methods of investigation)

  18. UAV Deployed Sensor System for Arctic Ocean Remote Sensing

    Science.gov (United States)

    Palo, S. E.; Lawrence, D.; Weibel, D.; LoDolce, G.; Krist, S.; Crocker, I.; Maslanik, J. A.

    2012-12-01

    The Marginal Ice Zone Observations and Processes Experiment (MIZOPEX), is an Arctic field project scheduled for summer 2013. The goals of the project are to understand how warming of the marginal ice zone affects sea ice melt and if this warming has been over or underestimated by satellite measurements. To achieve these goals calibrated physical measurements, both remote and in-situ, of the marginal ice zone over scales of square kilometers with a resolution of square meters is required. This will be accomplished with a suite of unmanned aerial vehicles (UAVs) equipped with both remote sensing and in-situ instruments, air deployed microbuoys, and ship deployed buoys. In this talk we will present details about the air-deployed micro-buoy (ADMB) and self-deployed surface-sonde (SDSS) components of the MIZOPEX project, developed at the University of Colorado. These systems were designed to explore the potential of low-cost, on-demand access to high-latitude areas of important scientific interest. Both the ADMB and SDSS share a common measurement suite with the capability to measure water temperature at three distinct depths and provide position information via GPS. The ADMBs are dropped from the InSitu ScanEagle UAV and expected to operate and log ocean temperatures for 14 days. The SDSS are micro UAVs that are designed to fly one-way to a region of interest and land at specified coordinates, thereafter becoming a surface sensor similar to the ADMB. A ScanEagle will periodically return to the deployment zone to gather ADMB/SDSS data via low power radio links. Design decisions based upon operational constraints and the current status of the ADMB and SDSS will be presented.

  19. Novel Capacitive Sensing System Design of a Microelectromechanical Systems Accelerometer for Gravity Measurement Applications

    Directory of Open Access Journals (Sweden)

    Zhu Li

    2016-09-01

    Full Text Available This paper presents an in-plane sandwich nano-g microelectromechanical systems (MEMS accelerometer. The proof-mass fabrication is based on silicon etching through technology using inductive coupled plasma (ICP etching. The capacitive detection system, which employs the area-changing sensing method, combines elementary capacitive pickup electrodes with periodic-sensing-array transducers. In order to achieve a large dynamic range with an ultrahigh resolution, the capacitive detection system employs two periodic-sensing-array transducers. Each of them can provide numbers for the signal period in the entire operating range. The suspended proof-mass is encapsulated between two glass caps, which results in a three dimensional structure. The measured resonant frequency and quality factor (Q are 13.2 Hz and 47, respectively. The calibration response of a ±0.7 g input acceleration is presented, and the accelerometer system presents a sensitivity of 122 V/g and a noise floor of 30 ng/√Hz (at 1 Hz, and 1 atm. The bias stability for a period of 10 h is 30 μg. The device has endured a shock up to ±2.6 g, and the full scale output appears to be approximately ±1.4 g presently. This work presents a new opportunity for highly sensitive MEMS fabrication to enable future high-precision measurement applications, such as for gravity measurements.

  20. Accuracy and Repeatability of the Gait Analysis by the WalkinSense System

    Directory of Open Access Journals (Sweden)

    Marcelo P. de Castro

    2014-01-01

    Full Text Available WalkinSense is a new device designed to monitor walking. The aim of this study was to measure the accuracy and repeatability of the gait analysis performed by the WalkinSense system. Descriptions of values recorded by WalkinSense depicting typical gait in adults are also presented. A bench experiment using the Trublu calibration device was conducted to statically test the WalkinSense. Following this, a dynamic test was carried out overlapping the WalkinSense and the Pedar insoles in 40 healthy participants during walking. Pressure peak, pressure peak time, pressure-time integral, and mean pressure at eight-foot regions were calculated. In the bench experiments, the repeatability (i among the WalkinSense sensors (within, (ii between two WalkinSense devices, and (iii between the WalkinSense and the Trublu devices was excellent. In the dynamic tests, the repeatability of the WalkinSense (i between stances in the same trial (within-trial and (ii between trials was also excellent (ICC > 0.90. When the eight-foot regions were analyzed separately, the within-trial and between-trials repeatability was good-to-excellent in 88% (ICC > 0.80 of the data and fair in 11%. In short, the data suggest that the WalkinSense has good-to-excellent levels of accuracy and repeatability for plantar pressure variables.

  1. Bioinert Anodic Alumina Nanotubes for Targeting of Endoplasmic Reticulum Stress and Autophagic Signaling: A Combinatorial Nanotube-Based Drug Delivery System for Enhancing Cancer Therapy.

    Science.gov (United States)

    Wang, Ye; Kaur, Gagandeep; Chen, Yuting; Santos, Abel; Losic, Dusan; Evdokiou, Andreas

    2015-12-16

    Although nanoparticle-based targeted delivery systems have gained promising achievements for cancer therapy, the development of sophisticated strategies with effective combinatorial therapies remains an enduring challenge. Herein, we report the fabrication of a novel nanomaterial, so-called anodic alumina nanotubes (AANTs) for proof-of-concept cancer therapy by targeting cell signaling networks. This strategy is to target autophagic and endoplasmic reticulum (ER) stress signaling by using thapsigargin (TG)-loaded AANTs cotreated with an autophagy inhibitor 3-methyladenine (3-MA). We first show that AANTs are nontoxic and can activate autophagy in different cell types including human fibroblast cells (HFF), human monocyte cells (THP-1), and human breast cancer cells (MDA-MB 231-TXSA). Treatment with 3-MA at a nontoxic dose reduced the level of autophagy induced by AANTs, and consequently sensitized breast cancer cells to AANTs-induced cellular stresses. To target autophagic and ER stress signaling networking, breast cancer cells were treated with 3-MA together with AANTs loaded with the prototype ER stress inducer TG. We demonstrated that 3-MA enhanced the cancer cell killing effect of AANTs loaded with TG. This effect was associated with enhanced ER stress signaling due to the combination effect of TG and 3-MA. These findings not only demonstrate the excellent biocompatibility of AANTs as novel biomaterials but also provide new opportunities for developing ER- and autophagy-targeted delivery systems for future clinical cancer therapy.

  2. P25 nanoparticles decorated on titania nanotubes arrays as effective drug delivery system for ibuprofen

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhang; Xie, Chunlin; Luo, Fei; Li, Ping; Xiao, Xiufeng, E-mail: xfxiao@fjnu.edu.cn

    2015-01-01

    Highlights: • P25 nanoparticles decorated on titania nanotube arrays were prepared by hydrothermal treatment. • P25 nanoparticles were conducive to improve the loading effect of ibuprofen into nanotube arrays. • The diameters of the decorated nanotubes were decrease markedly which led to an effective and prolonged drug release. - Abstract: In this study, uniformly distributed layer of P25 nanoparticles (NPs) decorated on titania (TiO{sub 2}) nanotubes (TNTs) arrays was prepared in a teflon-lined stainless steel autoclave by the hydrothermal treatment. To investigate the influence of the P25 concentration, different concentrations of P25 NPs were added into the solution to obtain the optimal decorative effect. TNTs decorated with P25 (TNTs–P25) and TNTs without P25 decorated on its surface were loaded with ibuprofen (IBU) via vacuum drying and its release properties were investigated. The samples were characterized by field emission scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The results indicated that P25 NPs were successfully decorated on the surface of TNTs by hydrothermal method and the optimal concentration was found to be 7.5 × 10{sup −4} M. P25 NPs decorated on TNTs led to a significant increase in the specific surface area of TNTs which was conducive to improve the loading effect of IBU. Importantly, the diameters of the decorated nanotubes were reduced to 100 ± 10 nm and the increase in roughness led to an effective and prolonged drug release.

  3. Integrating remote sensing, geographic information systems and global positioning system techniques with hydrological modeling

    Science.gov (United States)

    Thakur, Jay Krishna; Singh, Sudhir Kumar; Ekanthalu, Vicky Shettigondahalli

    2017-07-01

    Integration of remote sensing (RS), geographic information systems (GIS) and global positioning system (GPS) are emerging research areas in the field of groundwater hydrology, resource management, environmental monitoring and during emergency response. Recent advancements in the fields of RS, GIS, GPS and higher level of computation will help in providing and handling a range of data simultaneously in a time- and cost-efficient manner. This review paper deals with hydrological modeling, uses of remote sensing and GIS in hydrological modeling, models of integrations and their need and in last the conclusion. After dealing with these issues conceptually and technically, we can develop better methods and novel approaches to handle large data sets and in a better way to communicate information related with rapidly decreasing societal resources, i.e. groundwater.

  4. Using Distributed Fiber-Optic Sensing Systems to Estimate Inflow and Reservoir Properties

    NARCIS (Netherlands)

    Farshbaf Zinati, F.

    2014-01-01

    Recent developments in the deployment of distributed fiber-optic sensing systems in horizontal wells carry the promise to lead to a new, cheap and reliable way of monitoring production and reservoir performance. Practical applicability of distributed pressure sensing for quantitative inflow detectio

  5. Analyzing Fourier Transforms for NASA DFRC's Fiber Optic Strain Sensing System

    Science.gov (United States)

    Fiechtner, Kaitlyn Leann

    2010-01-01

    This document provides a basic overview of the fiber optic technology used for sensing stress, strain, and temperature. Also, the document summarizes the research concerning speed and accuracy of the possible mathematical algorithms that can be used for NASA DFRC's Fiber Optic Strain Sensing (FOSS) system.

  6. Novel Platform Development Using an Assembly of Carbon Nanotube, Nanogold and Immobilized RNA Capture Element towards Rapid, Selective Sensing of Bacteria

    Directory of Open Access Journals (Sweden)

    Elizabeth I. Maurer

    2012-06-01

    Full Text Available This study examines the creation of a nano-featured biosensor platform designed for the rapid and selective detection of the bacterium Escherichia coli. The foundation of this sensor is carbon nanotubes decorated with gold nanoparticles that are modified with a specific, surface adherent ribonucleiuc acid (RNA sequence element. The multi-step sensor assembly was accomplished by growing carbon nanotubes on a graphite substrate, the direct synthesis of gold nanoparticles on the nanotube surface, and the attachment of thiolated RNA to the bound nanoparticles. The application of the compounded nano-materials for sensor development has the distinct advantage of retaining the electrical behavior property of carbon nanotubes and, through the gold nanoparticles, incorporating an increased surface area for additional analyte attachment sites, thus increasing sensitivity. We successfully demonstrated that the coating of gold nanoparticles with a selective RNA sequence increased the capture of E. coli by 189% when compared to uncoated particles. The approach to sensor formation detailed in this study illustrates the great potential of unique composite structures in the development of a multi-array, electrochemical sensor for the fast and sensitive detection of pathogens.

  7. The calcium-sensing receptor and the reproductive system

    Directory of Open Access Journals (Sweden)

    Isabella Ellinger

    2016-08-01

    Full Text Available Active placental transport of maternal serum calcium (Ca2+ to the offspring is pivotal for proper development of the fetal skeleton as well as various organ systems. Moreover, extracellular Ca2+ levels impact on distinct processes in mammalian reproduction. The calcium-sensing receptor (CaSR translates changes in extracellular Ca2+-concentrations into cellular reactions. This review summarizes current knowledge on the expression of CaSR and its putative functions in reproductive organs. CaSR was detected in placental cells mediating materno-fetal Ca2+-transport such as the the murine intraplacental yolk sac and the human syncytiotrophoblast. As shown in casr knock-out mice, ablation of CaSR downregulates transplacental Ca2+-transport. Receptor expression was reported in human and rat ovarian surface epithelial cells, where CaSR activation stimulates cell proliferation. In follicles of various species a role of CaSR activation in oocyte maturation was suggested. Based on studies in avian follicles, the activation of CaSR expressed in granulosa cells may support the survival of follicles after their selection. CaSR in rat and equine sperms was functionally linked to sperm motility and sperm capacitation. Implantation involves complex interactions between the blastocyst and the uterine epithelium. During early pregnancy, CaSR expression at the implantation site as well as in decidual cells indicates that CaSR is important for blastocyst implantation and decidualization in the rat uterus. Localization of CaSR in human extravillous cytotrophoblasts suggests a role of CaSR in placentation. Overall, evidence for functional involvement of CaSR in physiologic mammalian reproductive processes exists. Moreover, several studies reported altered expression of CaSR in cells of reproductive tissues under pathologic conditions. However, in many tissues we still lack knowledge on physiological ligands activating CaSR, CaSR-linked G-proteins, activated

  8. Thermal Infrared Remote Sensing of the Yellowstone Geothermal System

    Science.gov (United States)

    Vaughan, R. G.; Keszthelyi, L. P.; Heasler, H.; Jaworowski, C.; Lowenstern, J. B.; Schneider, D. J.

    2009-12-01

    The Yellowstone National Park (YNP) geothermal system is one of the largest in the world, with thousands of individual thermal features ranging in size from a few centimeters to tens of meters across, (e.g., fumaroles, geysers, mud pots and hot spring pools). Together, large concentrations of these thermal features make up dozens of distinct thermal areas, characterized by sparse vegetation, hydrothermally altered rocks, and usually either sinter, travertine, or acid sulfate alteration. The temperature of these thermal features generally ranges from ~30 to ~93 oC, which is the boiling temperature of water at the elevation of Yellowstone. In-situ temperature measurements of various thermal features are sparse in both space and time, but they show a dynamic time-temperature relationship. For example, as geysers erupt and send pulses of warm water down slope, the warm water cools rapidly and is then followed by another pulse of warm water, on time scales of minutes. The total heat flux from the Park’s thermal features has been indirectly estimated from chemical analysis of Cl- flux in water flowing from Yellowstone’s rivers. We are working to provide a more direct measurement, as well as estimates of time variability, of the total heat flux using satellite multispectral thermal infrared (TIR) remote sensing data. Over the last 10 years, NASA’s orbiting ASTER and MODIS instruments have acquired hundreds and thousands of multispectral TIR images, respectively, over the YNP area. Compared with some volcanoes, Yellowstone is a relatively low-temperature geothermal system, with low thermal contrast to the non-geothermal surrounding areas; therefore we are refining existing techniques to extract surface temperature and thermal flux information. This task is complicated by issues such as, during the day, solar heated surfaces may be warmer than nearby geothermal features; and there is some topographic (elevation) influence on surface temperatures, even at night. Still

  9. A Spectrum Sensing Network for Cognitive PMSE Systems

    Science.gov (United States)

    Brendel, Johannes; Riess, Steffen; Stoeckle, Andreas; Rummel, Rafael; Fischer, Georg

    2012-09-01

    This article is about a Spectrum Sensing Network (SSN) which generates an accurate radio environment map (e.g. power over frequency, time, and location) from a given application area. It is intended to be used in combination with cognitive Program Making and Special Events (PMSE) devices (e.g. wireless microphones) to improve their operation reliability. The SSN consists of a distributed network of multiple scanning radio receivers and a central data management and storage unit. The parts of the SSN are presented in detail and the advantages and use cases of such a sensing network structure will be outlined.

  10. Dynamic measurement of physical conditions in daily life by body area network sensing system

    Energy Technology Data Exchange (ETDEWEB)

    Takayama, S; Tanaka, T; Takahashi, N; Matsuda, Y; Kariya, K, E-mail: s-tkym@se.ritsumi.ac.j [Department of Electrical and Electronics Engineering, Faculty of Science and Engineering, Ritsumeikan University Noji, Kusatsu, Shiga 55-8577 (Japan)

    2010-07-01

    This paper shows the measurement system to monitor physical conditions dynamically in dairy life. The measurement system for physical conditions in motion must be wearable and wireless connected. Body area network sensing system (BANSS) is a kind of the system to realize the conditions. BANSS is the system constructed with host system and plural sensing nodes. Sensing node is constructed with sensors, analogue/digital convertor(ADC), peripheral interface component(PIC), memory and near field communication device(NFCD). The NFCD in this system is Zigbee. Zigbee is the most suitable to construct wireless network system easily. BANSS is not only the system to measure physical parameters. BANSS informs current physical conditions and advises to keep suitable physical strength. As an application of BANSS, the system managing heart rate in walking is shown. By using this system, users can exercise in condition of a constant physical strength.

  11. Non Radiation Hardened Microprocessors in Spaced Based Remote Sensing Systems

    Science.gov (United States)

    Decoursey, Robert J.; Estes, Robert F.; Melton, Ryan

    2006-01-01

    The CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) mission is a comprehensive suite of active and passive sensors including a 20Hz 230mj Nd:YAG lidar, a visible wavelength Earth-looking camera and an imaging infrared radiometer. CALIPSO flies in formation with the Earth Observing System Post-Meridian (EOS PM) train, provides continuous, near-simultaneous measurements and is a planned 3 year mission. CALIPSO was launched into a 98 degree sun synchronous Earth orbit in April of 2006 to study clouds and aerosols and acquires over 5 gigabytes of data every 24 hours. The ground track of one CALIPSO orbit as well as high and low intensity South Atlantic Anomaly outlines is shown. CALIPSO passes through the SAA several times each day. Spaced based remote sensing systems that include multiple instruments and/or instruments such as lidar generate large volumes of data and require robust real-time hardware and software mechanisms and high throughput processors. Due to onboard storage restrictions and telemetry downlink limitations these systems must pre-process and reduce the data before sending it to the ground. This onboard processing and realtime requirement load may mean that newer more powerful processors are needed even though acceptable radiation-hardened versions have not yet been released. CALIPSO's single board computer payload controller processor is actually a set of four (4) voting non-radiation hardened COTS Power PC 603r's built on a single width VME card by General Dynamics Advanced Information Systems (GDAIS). Significant radiation concerns for CALIPSO and other Low Earth Orbit (LEO) satellites include the South Atlantic Anomaly (SAA), the north and south poles and strong solar events. Over much of South America and extending into the South Atlantic Ocean the Van Allen radiation belts dip to just 200-800km and spacecraft entering this area are subjected to high energy protons and experience higher than normal Single Event Upset

  12. Transitional Failure of Carbon Nanotube Systems under a Combination of Tension and Torsion

    Directory of Open Access Journals (Sweden)

    Byeong-Woo Jeong

    2012-01-01

    Full Text Available Transitional failure envelopes of single- and double-walled carbon nanotubes under combined tension-torsion are predicted using classical molecular dynamics simulations. The observations reveal that while the tensile failure load decreases with combined torsion, the torsional buckling moment increases with combined tension. As a result, the failure envelopes under combined tension-torsion are definitely different from those under pure tension or torsion. In such combined loading, there is a multitude of failure modes (tensile failure and torsional buckling, and the failure consequently exhibits the feature of transitional failure envelopes. In addition, the safe region of double-walled carbon nanotubes is significantly larger than that of single-walled carbon nanotubes due to the differences in the onset of torsional buckling.

  13. Fibre optic distributed scattering sensing system: perspectives and challenges for high performance applications

    Institute of Scientific and Technical Information of China (English)

    Marc Niklès

    2007-01-01

    As fiber optic distributed scattering sensing systems are providing innovative solutions for the monitoring of large structures, the comparison of different techniques and solutions is difficult because of the lack of standardized specifications and the difficulty associated to the characterization of such systems. The article presents a tentative definition of performance specifications and qualification procedures applicable to fiber optic distributed sensing systems aiming at providing clear guidelines for their design, specifications, qualification, application and selection.

  14. Nonlinearity characterization of temperature sensing systems for integrated circuit testing by intermodulation products monitoring.

    Science.gov (United States)

    Altet, J; Mateo, D; Perpiñà, X; Grauby, S; Dilhaire, S; Jordà, X

    2011-09-01

    This work presents an alternative characterization strategy to quantify the nonlinear behavior of temperature sensing systems. The proposed approach relies on measuring the temperature under thermal sinusoidal steady state and observing the intermodulation products that are generated within the sensing system itself due to its nonlinear temperature-output voltage characteristics. From such intermodulation products, second-order interception points can be calculated as a figure of merit of the measuring system nonlinear behavior. In this scenario, the present work first shows a theoretical analysis. Second, it reports the experimental results obtained with three thermal sensing techniques used in integrated circuits.

  15. Impregnation of Catalytic Metals in Single-Walled Carbon Nanotubes for Toxic Gas Conversion in Life Support System

    Science.gov (United States)

    Li, Jing; Wignarajah, Kanapathipillai; Cinke, Marty; Partridge, Harry; Fisher, John

    2004-01-01

    Carbon nanotubes (CNTs) possess extraordinary properties such as high surface area, ordered chemical structure that allows functionalization, larger pore volume, and very narrow pore size distribution that have attracted considerable research attention from around the world since their discovery in 1991. The development and characterization of an original and innovative approach for the control and elimination of gaseous toxins using single walled carbon nanotubes (SWNTs) promise superior performance over conventional approaches due to the ability to direct the selective uptake of gaseous species based on their controlled pore size, increased adsorptive capacity due to their increased surface area and the effectiveness of carbon nanotubes as catalyst supports for gaseous conversion. We present our recent investigation of using SWNTs as catalytic supporting materials to impregnate metals, such as rhodium (Rh), palladium (Pd) and other catalysts. A protocol has been developed to oxidize the SWNTs first and then impregnate the Rh in aqueous rhodium chloride solution, according to unique surface properties of SWNTs. The Rh has been successfully impregnated in SWNTs. The Rh-SWNTs have been characterized by various techniques, such as TGA, XPS, TEM, and FTIR. The project is funded by a NASA Research Announcement Grant to find applications of single walled nanocarbons in eliminating toxic gas Contaminant in life support system. This knowledge will be utilized in the development of a prototype SWNT KO, gas purification system that would represent a significant step in the development of high efficiency systems capable of selectively removing specific gaseous for use in regenerative life support system for human exploration missions.

  16. Impregnation of Catalytic Metals in Single-Walled Carbon Nanotubes for Toxic Gas Conversion in Life Support System

    Science.gov (United States)

    Li, Jing; Wignarajah, Kanapathipillai; Cinke, Marty; Partridge, Harry; Fisher, John

    2004-01-01

    Carbon nanotubes (CNTs) possess extraordinary properties such as high surface area, ordered chemical structure that allows functionalization, larger pore volume, and very narrow pore size distribution that have attracted considerable research attention from around the world since their discovery in 1991. The development and characterization of an original and innovative approach for the control and elimination of gaseous toxins using single walled carbon nanotubes (SWNTs) promise superior performance over conventional approaches due to the ability to direct the selective uptake of gaseous species based on their controlled pore size, increased adsorptive capacity due to their increased surface area and the effectiveness of carbon nanotubes as catalyst supports for gaseous conversion. We present our recent investigation of using SWNTs as catalytic supporting materials to impregnate metals, such as rhodium (Rh), palladium (Pd) and other catalysts. A protocol has been developed to oxidize the SWNTs first and then impregnate the Rh in aqueous rhodium chloride solution, according to unique surface properties of SWNTs. The Rh has been successfully impregnated in SWNTs. The Rh-SWNTs have been characterized by various techniques, such as TGA, XPS, TEM, and FTIR. The project is funded by a NASA Research Announcement Grant to find applications of single walled nanocarbons in eliminating toxic gas Contaminant in life support system. This knowledge will be utilized in the development of a prototype SWNT KO, gas purification system that would represent a significant step in the development of high efficiency systems capable of selectively removing specific gaseous for use in regenerative life support system for human exploration missions.

  17. Deterministic Designs with Deterministic Guarantees: Toeplitz Compressed Sensing Matrices, Sequence Designs and System Identification

    CERN Document Server

    Saligrama, Venkatesh

    2008-01-01

    In this paper we present a new family of discrete sequences having ``random like'' uniformly decaying auto-correlation properties. The new class of infinite length sequences are higher order chirps constructed using irrational numbers. Exploiting results from the theory of continued fractions and diophantine approximations, we show that the class of sequences so formed has the property that the worst-case auto-correlation coefficients for every finite length sequence decays at a polynomial rate. These sequences display doppler immunity as well. We also show that Toeplitz matrices formed from such sequences satisfy restricted-isometry-property (RIP), a concept that has played a central role recently in Compressed Sensing applications. Compressed sensing has conventionally dealt with sensing matrices with arbitrary components. Nevertheless, such arbitrary sensing matrices are not appropriate for linear system identification and one must employ Toeplitz structured sensing matrices. Linear system identification p...

  18. Distributed optical fiber perturbation sensing system based on Mach-Zehnder interferometer

    Institute of Scientific and Technical Information of China (English)

    Wengang WANG; Deming LIU; Hairong LIU; Qizhen SUN; Zhifeng SUN; Xu ZHANG; Ziheng XU

    2009-01-01

    A novel distributed optical fiber vibration-sensing system based on Mach-Zehnder interferometer has been designed and experimentally demonstrated. Firstly, the principle of Mach-Zehnder optical path interferometer technique is clarified. The output of the Mach-Zehnder interferometer is proportional to the phase shift induced by the perturbation. Secondly, the system consists of the laser diode (LD) as the light source, fiber, Mach-Zehnder optical interferometers as the sensing units, a 1×N star fiber-optic coupler, an N×1 fiber-optic coupler, a photodiode (PD) detector, and a computer used in signal processing. The entire monitoring region of this system is divided into several small zones, and each small monitoring zone is independent from each other. All of the small monitoring zones have their own sensing unit, which is defined by Mach-Zehnder optical interferometer. A series of sensing units are connected by the star fiber-optic couplers to form a whole sensing net. Thirdly, signal-processing techniques are subsequently used to calculate the phase shift to estimate whether intruders appear. The sensing system is able to locate the vibration signal simultaneously, includ-ing multiple vibrations at different positions, by employing the time-division multiplexed (TDM) technique. Finally, the operation performance of the proposed system is tested in the experiment lab with the conditions as follows: the number of the sensing units is 3, the length of the sensing fiber is 50 m, and the wavelength of the light diode is 1550nm. Based on these investigations, the fiber surrounding alert system is achieved. We have experimen-tally demonstrated that the sensing system can measure both the frequency and position of the vibration in real time, with a spatial positional resolution better than 50 m in an area of 1 km2.

  19. Multi-point temperature sensing using a linear-cavity lasing system.

    Science.gov (United States)

    Kishikawa, Hiroki; Okada, Mao; Takahashi, Kazuto; Chen, Po-Jung; Goto, Nobuo; Yu, Yi-Lin; Liaw, Shien-Kuei

    2017-04-10

    A multi-point fiber sensing system formed from a linear cavity laser is proposed. Various optical sensing systems have been investigated, for example, using fiber Bragg grating (FBG) and Brillouin scattering for multi-point sensing. This paper focuses on a simple sensing system by using multi-wavelength lasing with parallel cavities and a semiconductor optical amplifier (SOA). First, optical nonlinearity in amplification of the SOA is discussed to clarify the effects of gain saturation and four-wave mixing on the proposed multi-channel sensing system. And then lasing conditions in the linear cavity laser consisting of an SOA, an arrayed waveguide grating (AWG), and FBGs are theoretically investigated. The multi-wavelength lasing power is found to be limited mainly by gain saturation in the SOA. The lasing power for the eight-channel system is evaluated to be -8.5  dBm when the total loss in the linear cavity is 10 dB. The lasing power can be increased by 3 dB when the channel number is decreased to four. Next, multi-wavelength lasing in the cavity consisting of an SOA, an AWG, a loop mirror, and fiber mirror reflectors is experimentally demonstrated up to eight channels. Finally, two-channel temperature sensing ranging from 13°C to 76°C is experimentally confirmed by using two FBGs as the sensing elements with an AWG having 100-GHz bandwidth.

  20. A power system design and analysis of carbon nano-tubes field emission displays

    Science.gov (United States)

    Wang, Jong C.; Yao, W. C.

    2006-01-01

    In new generation Flat Panel Displays(FPD), a lot of design methods are being deployed, including OLED, PDP, TFT-LCD, Back Projection and Field Emission Display(FED) etc. These new generation FPDs have their respective pluses and minuses. Each has its selling points and market attractions. But among them, FED principles are most close to that of CRT displays. Not only FEDs are advantageous in their good degree of saturation of color, but also they have excellent contrast, luminance and electricity consumption etc. It has been considered as the main products of future generation FPDs. Japan and countries all over the world are successively proposing and launching related FED products in the fields. This will not only drive the FEDs into a wave of new trends, but also it will be able to replace most of the current FPD products within a short time. In this paper, based on these solid trends, we are determined to put into our resources and efforts to perform research on these important FEDs technologies and products, particularly in Carbon Nano-Tubes FEDs(CNT-FED). Our research group has already performed research on CNT-FED subjects for almost three years. During the course of our research, we have run into a lot of issues and problems. We have made every effort to overcome some of them. This paper performs comparative analysis of three power option for small size (4-inch) CNT-FEDs to drive the FED effects such as the direct current power, pulsed power and sinusoidal power respectively. This paper performs comparative analysis of three power options for small sized CNT-FEDs. It was concluded that the pulsed power option will produce the best results overall among the three power options. It is felt that these data presented can then be referenced and used to design a power system circuit to get an optimum design for better luminance and least power consumption for small sized commercial CNT-FED products.

  1. NiCoBP-doped carbon nanotube hybrid: A novel oxidase mimetic system for highly efficient electrochemical immunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Bing; He, Yu; Liu, Bingqian; Tang, Dianping, E-mail: dianping.tang@fzu.edu.cn

    2014-12-03

    Highlights: • We report a new oxidase mimetic system for highly efficient electrochemical immunoassay. • NiCoBP-doped carbon nanotube hybrids were used as the nanocatalysts. • NiCoBP-doped carbon nanotube hybrids were used as the mimic oxidase. - Abstract: NiCoBP-doped multi-walled carbon nanotube (NiCoBP–MWCNT) was first synthesized by using induced electroless-plating method and functionalized with the biomolecules for highly efficient electrochemical immunoassay of prostate-specific antigen (PSA, used as a model analyte). We discovered that the as-synthesized NiCoBP–MWCNT had the ability to catalyze the glucose oxidization with a stable and well-defined redox peak. The catalytic current increased with the increment of the immobilized NiCoBP–MWCNT on the electrode. Transmission electron microscope (TEM) and energy dispersive X-ray spectrometry (EDX) were employed to characterize the as-prepared NiCoBP–MWCNT. Using the NiCoBP–MWCNT-conjugated anti-PSA antibody as the signal-transduction tag, a new enzyme-free electrochemical immunoassay protocol could be designed for the detection of target PSA on the capture antibody-functionalized immunosensing interface. Experimental results revealed that the designed immunoassay system could exhibit good electrochemical responses toward target PSA, and allowed the detection of PSA at a concentration as low as 0.035 ng mL{sup −1}. More importantly, the NiCoBP-MWCNT-based oxidase mimetic system could be further extended for the monitoring of other low-abundance proteins or disease-related biomarkers by tuning the target antibody.

  2. Method for nano-pumping using carbon nanotubes

    Science.gov (United States)

    Insepov, Zeke; Hassanein, Ahmed

    2009-12-15

    The present invention relates generally to the field of nanotechnology, carbon nanotubes and, more specifically, to a method and system for nano-pumping media through carbon nanotubes. One preferred embodiment of the invention generally comprises: method for nano-pumping, comprising the following steps: providing one or more media; providing one or more carbon nanotubes, the one or more nanotubes having a first end and a second end, wherein said first end of one or more nanotubes is in contact with the media; and creating surface waves on the carbon nanotubes, wherein at least a portion of the media is pumped through the nanotube.

  3. Calibration and deployment of a fiber-optic sensing system for monitoring debris flows

    National Research Council Canada - National Science Library

    Huang, Ching-Jer; Chu, Chung-Ray; Tien, Tsung-Mo; Yin, Hsiao-Yuen; Chen, Ping-Sen

    2012-01-01

    .... The proposed sensing system comprises a demodulator (BraggSCOPE, FS5500), which includes a broadband light source and a data logger, a four-port coupler and four Fiber Bragg Grating (FBG) accelerometers...

  4. NASA Armstrong Flight Research Center (AFRC) Fiber Optic Sensing System (FOSS) Technology

    Science.gov (United States)

    Richards, Lance; Parker, Allen R.; Piazza, Anthony; Chan, Patrick; Hamory, Phil; Pena, Frank

    2014-01-01

    Attached is a power point presentation created to assist the Tech Transfer Office and the FOSS project team members in responding to inquiries from the public about the capabilities of the Fiber Optic Sensing System.

  5. PASSIVE WIRELESS MULTI-SENSOR TEMPERATURE AND PRESSURE SENSING SYSTEM USING ACOUSTIC WAVE DEVICES Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal describes the development of passive surface acoustic wave (SAW) sensors and multi-sensor systems for NASA application to remote wireless sensing of...

  6. New Sensing Application to Diagnose Power Semiconductor Aging in Actuator Power Drive Systems

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper presents a new sensing application to diagnose power semiconductor aging in power drive systems. It has been shown previously that device parasitic...

  7. Applications of Remote Sensing and Geographic Information System (GIS) in Archaeology

    Digital Repository Service at National Institute of Oceanography (India)

    ManiMurali, R.

    The advancement of remote sensing technology and the analysing capability of Geographical Information System (GIS) can very well be used in the science of Archaeology. Though these subjects look apart, they can be studied in conjunction with each...

  8. Affordable dual-sensing proximity sensor for touchless interactive systems

    KAUST Repository

    Nassar, Joanna M.

    2016-09-13

    We report an ultra-low cost flexible proximity sensor using only off-the-shelf recyclable materials such as aluminum foil, napkin and double-sided tape. Unlike previous reports, our device structure exhibits two sensing capabilities in one platform, with outstanding long detection range of 20 cm and pressure sensitivity of 0.05 kPa. This is the first ever demonstration of a low-cost, accessible, and batch manufacturing process for pressure and proximity sensing on a singular platform. The mechanical flexibility of the sensor makes it possible to mount on various irregular platforms, which is vital in many areas, such as robotics, machine automation, vehicular technology and inspection tools.

  9. Dynamic behavior of a black phosphorus and carbon nanotube composite system

    Science.gov (United States)

    Shi, Jiao; Cai, Haifang; Cai, Kun; Qin, Qing-Hua

    2017-01-01

    A double walled nanotube composite is constructed by placing a black-phosphorene-based nanotube (BPNT) in a carbon nanotube (CNT). When driving the CNT to rotate by stators in a thermal driven rotary nanomotor, the BPNT behaves differently from the CNT. For instance, the BPNT can be actuated to rotate by the CNT, but its rotational acceleration differs from that of the CNT. The BPNT oscillates along the tube axis when it is longer than the CNT. The results obtained indicate that the BPNT functions with high structural stability when acting as a rotor with rotational frequency of ~20 GHz at 250 K. If at a higher temperature than 250 K, say 300 K, the rotating BPNT shows weaker structural stability than its status at 250 K. When the two tubes in the rotor are of equal length, the rotational frequency of the BPNT drops rapidly after the BPNT is collapsed, owing to more broken P-P bonds. When the black-phosphorene nanotube is longer than the CNT, it rotates synchronously with the CNT even if it is collapsed. Hence, in the design of a nanomotor with a rotor from BPNT, the working rotational frequency should be lower than a certain threshold at a higher temperature.

  10. Model-Free Adaptive Sensing and Control for a Piezoelectrically Actuated System

    OpenAIRE

    Jin-Wei Liang; Hung-Yi Chen

    2010-01-01

    Since the piezoelectrically actuated system has nonlinear and time-varying behavior, it is difficult to establish an accurate dynamic model for a model-based sensing and control design. Here, a model-free adaptive sliding controller is proposed to improve the small travel and hysteresis defects of piezoelectrically actuated systems. This sensing and control strategy employs the functional approximation technique (FAT) to establish the unknown function for eliminating the model-based requireme...

  11. FBG Temperature and Pressure Sensing System for Hot Water Pipeline of Petrochemical Factory

    Institute of Scientific and Technical Information of China (English)

    Guo-Hui Lü; Shao-Hua Shang; Xu Jiang; Jin-Ping Ou; Chao Yang; Chuan-Di Li; Wei Xu

    2008-01-01

    A spatial and wavelength division multi-plexing fiber Bragg grating (FBG) sensing system is reported for monitoring the temperature and the pressure (T-P) of hot water pipeline in petrochemical factory. The FBG sensing system has 72 channels independently, and it provides the capability to monitor large number sensors at same time. A resolution of 0.1 ℃ and 0.01 MPa with a measurement bandwidth of 150 Hz has been achieved.

  12. TiO2 nanotube composite layers as delivery system for ZnO and Ag nanoparticles - an unexpected overdose effect decreasing their antibacterial efficacy.

    Science.gov (United States)

    Roguska, A; Belcarz, A; Pisarek, M; Ginalska, G; Lewandowska, M

    2015-06-01

    Enhancement of biocompatibility and antibacterial properties of implant materials is potentially beneficial for their practical value. Therefore, the use of metallic and metallic oxide nanoparticles as antimicrobial coatings components which induce minimized antibacterial resistance receives currently particular attention. In this work, TiO2 nanotubes layers loaded with ZnO and Ag nanoparticles were designed for biomedical coatings and delivery systems and evaluated for antimicrobial activity. TiO2 nanotubes themselves exhibited considerable and diameter-dependent antibacterial activity against planktonic Staphylococcus epidermidis cells but favored bacterial adhesion. Loading of nanotubes with moderate amount of ZnO nanoparticles significantly diminished S. epidermidis cell adhesion and viability just after 1.5h contact with modified surfaces. However, an increase of loaded ZnO amount unexpectedly altered the structure of nanoparticle-nanolayer, caused partial closure of nanotube interior and significantly reduced ZnO solubility and antibacterial efficacy. Co-deposition of Ag nanoparticles enhanced the antibacterial properties of synthesized coatings. However, the increase of ZnO quantity on Ag nanoparticles co-deposited surfaces favored the adhesion of bacterial cells. Thus, ZnO/Ag/TiO2 nanotube composite layers may be promising delivery systems for combating post-operative infections in hard tissue replacement procedures. However, the amount of loaded antibacterial agents must be carefully balanced to avoid the overdose and reduced efficacy.

  13. The sense of agency: a philosophical and empirical review of the "Who" system.

    Science.gov (United States)

    de Vignemont, F; Fourneret, P

    2004-03-01

    How do I know that I am the person who is moving? According to Wittgenstein (1958), the sense of agency involves a primitive notion of the self used as subject, which does not rely on any prior perceptual identification and which is immune to error through misidentification. However, the neuroscience of action and the neuropsychology of schizophrenia show the existence of specific cognitive processes underlying the sense of agency--the "Who" system--which is disrupted in delusions of control. Yet, we have to be careful in the interpretation of such clinical symptoms, which cannot be so easily reduced to deficit of action monitoring or to lack of action awareness. Moreover, we should refine the definition of the sense of agency by distinguishing the sense of initiation and the sense of one's own movements. A conceptual analysis of the empirical data will lead us to establish the taxonomy of the different levels of action representations.

  14. Modeling Chemical Detection Sensitivities of Active and Passive Remote Sensing Systems

    Energy Technology Data Exchange (ETDEWEB)

    Scharlemann, E T

    2003-07-28

    During nearly a decade of remote sensing programs under the auspices of the U. S. Department of Energy (DOE), LLNL has developed a set of performance modeling codes--called APRS--for both Active and Passive Remote Sensing systems. These codes emphasize chemical detection sensitivity in the form of minimum detectable quantities with and without background spectral clutter and in the possible presence of other interfering chemicals. The codes have been benchmarked against data acquired in both active and passive remote sensing programs at LLNL and Los Alamos National Laboratory (LANL). The codes include, as an integral part of the performance modeling, many of the data analysis techniques developed in the DOE's active and passive remote sensing programs (e.g., ''band normalization'' for an active system, principal component analysis for a passive system).

  15. Technical foundation research on high resolution remote sensing system of China's coastal zone

    Institute of Scientific and Technical Information of China (English)

    YANG Xiaomei; LAN Rongqin; DU Yunyan; CHEN Xiufa

    2004-01-01

    China's coastal zone is a region with a highly developed economy that contrasts clearly with the slow paced regular investigation on its natural environment,which cannot keep pace with the requirement of economic development and modem management. Laying a theoretical foundation for the modem management of China's costal zone is aimed at.This research focuses on the following processing and analyzing technologies for coastal zone high-resolution remote sensing data: organization and management of large amounts of high-resolution remote sensing data, quick and precise spatial positioning system,algorithms for image fusion in feature level and coastal zone feature extraction. They will form a technical foundation of the system. And, ifcombined with other research results such as coastal zone remote sensing classification system and its mapping subsystem, an advanced technical frame for remote sensing investigation of coastal zone resource will be constructed.

  16. Engineering bacterial two-component system PmrA/PmrB to sense lanthanide ions.

    Science.gov (United States)

    Liang, Haihua; Deng, Xin; Bosscher, Mike; Ji, Quanjiang; Jensen, Mark P; He, Chuan

    2013-02-13

    The Salmonella PmrA/PmrB two-component system uses an iron(III)-binding motif on the cell surface to sense the environmental or host ferric level and regulate PmrA-controlled gene expression. We replaced the iron(III)-binding motif with a lanthanide-binding peptide sequence that is known to selectively recognize trivalent lanthanide ions. The newly engineered two-component system (PmrA/PmrB) can effectively sense lanthanide ion and regulate gene expression in E. coli . This work not only provides the first known lanthanide-based sensing and response in live cells but also demonstrates that the PmrA/PmrB system is a suitable template for future synthetic biology efforts to construct bacteria that can sense and respond to other metal ions in remediation or sequestration.

  17. Nanosensors for the smart city : new insight on promising carbon nanotubes devices

    OpenAIRE

    Lebental, Bérengère

    2011-01-01

    The development of nanosensors for the smart-city is discussed in the framework of the Sense-City Equipex project. Two types of carbon nanotubes based sensors are discussed, a field effect transistor using a carbon nanotubes randow network as channel for humidity sensing and a microsonar using an aligned array of carbon nanotubes as vibrating membrane for microporosity monitoring in concrete. The Sense-city project is also described.

  18. Optimizing the e-beam profile of a single carbon nanotube field emission device for electric propulsion systems

    Directory of Open Access Journals (Sweden)

    Juliano Fujioka Mologni

    2010-04-01

    Full Text Available Preliminary studies on field emission (FE arrays comprised of carbon nanotubes (CNT as an electron source for electric propulsion system show remarkably promising results. Design parameters for a carbon nanotube (CNT field-emission device operating on triode configuration were numerically simulated and optimized in order to enhance the e-beam focusing quality. An additional focus gate (FG was integrated to the device to control the profile of the emitted e-beam. An axisymmetric finite element model was developed to calculate the electric field distribution on the vacuum region and a modified Fowler-Nordheim (FN equation was used to evaluate the current density emission and the effective emitter area. Afterward, a FE simulation was employed in order to calculate the trajectory of the emitted electrons and define the electron-optical properties of the e-beam. The integration of the FG was fully investigated via computational intelligence techniques. The best performance device according to our simulations presents a collimated e-beam profile that suits well for field emission displays, magnetic field detection and electron microscopy. The automated computational design tool presented in this study strongly benefits the robust design of integrated electron-optical systems for vacuum field emission applications, including electrodynamic tethering and electric propulsion systems.

  19. LAnd surface remote sensing Products VAlidation System (LAPVAS) and its preliminary application

    Science.gov (United States)

    Lin, Xingwen; Wen, Jianguang; Tang, Yong; Ma, Mingguo; Dou, Baocheng; Wu, Xiaodan; Meng, Lumin

    2014-11-01

    The long term record of remote sensing product shows the land surface parameters with spatial and temporal change to support regional and global scientific research widely. Remote sensing product with different sensors and different algorithms is necessary to be validated to ensure the high quality remote sensing product. Investigation about the remote sensing product validation shows that it is a complex processing both the quality of in-situ data requirement and method of precision assessment. A comprehensive validation should be needed with long time series and multiple land surface types. So a system named as land surface remote sensing product is designed in this paper to assess the uncertainty information of the remote sensing products based on a amount of in situ data and the validation techniques. The designed validation system platform consists of three parts: Validation databases Precision analysis subsystem, Inter-external interface of system. These three parts are built by some essential service modules, such as Data-Read service modules, Data-Insert service modules, Data-Associated service modules, Precision-Analysis service modules, Scale-Change service modules and so on. To run the validation system platform, users could order these service modules and choreograph them by the user interactive and then compete the validation tasks of remote sensing products (such as LAI ,ALBEDO ,VI etc.) . Taking SOA-based architecture as the framework of this system. The benefit of this architecture is the good service modules which could be independent of any development environment by standards such as the Web-Service Description Language(WSDL). The standard language: C++ and java will used as the primary programming language to create service modules. One of the key land surface parameter, albedo, is selected as an example of the system application. It is illustrated that the LAPVAS has a good performance to implement the land surface remote sensing product

  20. Nutrient Sensing: Another Chemosensitivity of the Olfactory System

    Directory of Open Access Journals (Sweden)

    A-Karyn Julliard

    2017-07-01

    Full Text Available Olfaction is a major sensory modality involved in real time perception of the chemical composition of the external environment. Olfaction favors anticipation and rapid adaptation of behavioral responses necessary for animal survival. Furthermore, recent studies have demonstrated that there is a direct action of metabolic peptides on the olfactory network. Orexigenic peptides such as ghrelin and orexin increase olfactory sensitivity, which in turn, is decreased by anorexigenic hormones such as insulin and leptin. In addition to peptides, nutrients can play a key role on neuronal activity. Very little is known about nutrient sensing in olfactory areas. Nutrients, such as carbohydrates, amino acids, and lipids, could play a key role in modulating olfactory sensitivity to adjust feeding behavior according to metabolic need. Here we summarize recent findings on nutrient-sensing neurons in olfactory areas and delineate the limits of our knowledge on this topic. The present review opens new lines of investigations on the relationship between olfaction and food intake, which could contribute to determining the etiology of metabolic disorders.

  1. Integrated Electrochemical Analysis System with Microfluidic and Sensing Functions

    Directory of Open Access Journals (Sweden)

    Hiroaki Suzuki

    2008-02-01

    Full Text Available An integrated device that carries out the timely transport of solutions andconducts electroanalysis was constructed. The transport of solutions was based oncapillary action in overall hydrophilic flow channels and control by valves that operateon the basis of electrowetting. Electrochemical sensors including glucose, lactate,glutamic oxaloacetic transaminase (GOT, glutamic pyruvic transaminase (GPT, pH,ammonia, urea, and creatinine were integrated. An air gap structure was used for theammonia, urea, and creatinine sensors to realize a rapid response. To enhance thetransport of ammonia that existed or was produced by the enzymatic reactions, the pHof the solution was elevated by mixing it with a NaOH solution using a valve based onelectrowetting. The sensors for GOT and GPT used a freeze-dried substrate matrix torealize rapid mixing. The sample solution was transported to required sensing sites atdesired times. The integrated sensors showed distinct responses when a sample solutionreached the respective sensing sites. Linear relationships were observed between theoutput signals and the concentration or the logarithm of the concentration of theanalytes. An interferent, L-ascorbic acid, could be eliminated electrochemically in thesample injection port.

  2. Quorum sensing signal-response systems in Gram-negative bacteria.

    Science.gov (United States)

    Papenfort, Kai; Bassler, Bonnie L

    2016-08-11

    Bacteria use quorum sensing to orchestrate gene expression programmes that underlie collective behaviours. Quorum sensing relies on the production, release, detection and group-level response to extracellular signalling molecules, which are called autoinducers. Recent work has discovered new autoinducers in Gram-negative bacteria, shown how these molecules are recognized by cognate receptors, revealed new regulatory components that are embedded in canonical signalling circuits and identified novel regulatory network designs. In this Review we examine how, together, these features of quorum sensing signal-response systems combine to control collective behaviours in Gram-negative bacteria and we discuss the implications for host-microbial associations and antibacterial therapy.

  3. Development of Sense and Avoid system based on multi sensor integration for unmanned vehicle system

    Science.gov (United States)

    Legowo, Ari; Ramli, M. Faiz Bin; Syafiq Shamsudin, Syariful

    2017-03-01

    Unmanned Aerial Vehicles (UAV) have a great potential to replace manned aircraft in many tasks or missions. However, in order to allow these UAVs to execute their mission appropriately and especially to deploy them in national or civil airspace, UAVs must have a proper and reliable collision avoidance system. This avoidance system is known as a Sense and avoidance (SAA) system. The purpose of the system is to detect any obstacles either in static or moving condition and respond with proper avoidance maneuvers in order to maintain minimum separation distances. Therefore the research project deals with the development of a unique SAA system which is based on multisensory integration. In particular, it focuses on sensors, processing logic and hardware required on the UAVs to acquire situational awareness. Dissimilar kind of sensors which is optical and laser type is proposed to be employed, so that weaknesses from each individual sensor can be tolerated. Proper logics or algorithm related to the fusion of output from each sensor will also be studied.The combination of Extended KalmanFilter (EKF) and Differential Evolution(DE) method is used for the purpose of development of detection and tracking system which considered to be the main challenges in SAA system development. Subsequently, once the algorithms are put together, including maneuvers avoidance technique algorithm, the developed SAA system will be experimentally tested in order to validate and evaluate the overall capability of the system.

  4. Carbon nanotubes as plant growth regulators: effects on tomato growth, reproductive system, and soil microbial community.

    Science.gov (United States)

    Khodakovskaya, Mariya V; Kim, Bong-Soo; Kim, Jong Nam; Alimohammadi, Mohammad; Dervishi, Enkeleda; Mustafa, Thikra; Cernigla, Carl E

    2013-01-14

    Multi-walled carbon nanotubes (CNTs) can affect plant phenotype and the composition of soil microbiota. Tomato plants grown in soil supplemented with CNTs produce two times more flowers and fruit compared to plants grown in control soil. The effect of carbon nanotubes on microbial community of CNT-treated soil is determined by denaturing gradient gel electrophoresis and pyrosequencing analysis. Phylogenetic analysis indicates that Proteobacteria and Bacteroidetes are the most dominant groups in the microbial community of soil. The relative abundances of Bacteroidetes and Firmicutes are found to increase, whereas Proteobacteria and Verrucomicorbia decrease with increasing concentration of CNTs. The results of comparing diversity indices and species level phylotypes (OTUs) between samples showed that there is not a significant affect on bacterial diversity.

  5. Dispersion issues and thermal conductivity of polypropylene/multi wall carbon nanotube systems

    Science.gov (United States)

    Russo, Pietro; Patti, Antonella; Acierno, Domenico; Acierno, Stefano

    2016-05-01

    Three types of multiwall carbon nanotubes, one non-functionalized tubes and two functionalized with polar (amino and carboxyl) groups, were used as fillers in a polypropylene resin to develop nanocomposites with improved thermal conductivity. In particular, formulations containing up to 5% in volume of carbon nanotubes, prepared by melt blending, were analyzed in terms of dynamic rheological behavior of melts and thermal conductivity. The former can give information related to the build-up of internal network structures and to the level of dispersion of the fillers. Taking into account that the properties of nanocomposites are strictly related to these aspects, the enhancement of thermal conductivity with respect to the pristine matrix are discussed as a function of the filler content, dispersion of the filler and presence of internal structures.

  6. Relaxation lifetimes of plasmonically enhanced hybrid gold-carbon nanotubes systems

    Science.gov (United States)

    Glaeske, M.; Kumar, M.; Bisswanger, T.; Vaitiekenas, S.; Soci, C.; Narula, R.; Bruno, A.; Setaro, A.

    2017-06-01

    Recently, we introduced a novel hybridization route for carbon nanotubes using gold nanoparticles, whose close proximity neatly enhances their radiative emission. Here we investigate the mechanisms behind the enhancement by monitoring the de-excitation dynamics of our π-hybrids through two-color pump-probe time-resolved spectroscopy. The de-excitation process reveals a fast component and a slow component. We find that the presence of gold prominently affects the fast processes, indicating a stronger influence of the gold nanoparticle on the intra-band non-radiative relaxation than on the inter-band recombination of the single-walled carbon nanotube. By evaluating the de-excitation times, we estimate the balance between near-field pumping and the faster metal-induced de-excitation contributions, proving the enhanced pumping to be the leading mechanism.

  7. An Energy Efficient Cognitive Radio System with Quantized Soft Sensing and Duration Analysis

    KAUST Repository

    Alabbasi, Abdulrahman

    2015-03-09

    In this paper, an energy efficient cognitive radio system is proposed. The proposed design optimizes the secondary user transmission power and the sensing duration combined with soft-sensing information to minimize the energy per goodbit. Due to the non-convex nature of the problem we prove its pseudo-convexity to guarantee the optimal solution. Furthermore, a quantization scheme, that discretize the softsensing information, is proposed and analyzed to reduce the overload of the continuously adapted power. Numerical results show that our proposed system outperforms the benchmark systems. The impact of the quantization levels and other system parameters is evaluated in the numerical results.

  8. Laser induced effects in carbon nanotubes:implications for Raman characterization of functionalized systems

    OpenAIRE

    Olevik, David

    2009-01-01

    Carbon nanotubes (CNTs) have attracted attention over the past decade because of their outstanding mechanical and electronic properties. These tiny tubular shells made of carbon atoms can be metallic or semiconducting and while having diameters of only about one nanometer (10-9 m), they can be up to centimeters in length, making them quasi one-dimensional (molecular wires). Along with a Young's modulus several times that of steel, CNTs are close to perfect (ballistic) electric conductors and ...

  9. Recognition unit-free and self-cleaning photoelectrochemical sensing platform on TiO2 nanotube photonic crystals for sensitive and selective detection of dopamine release from mouse brain.

    Science.gov (United States)

    Xin, Yanmei; Li, Zhenzhen; Wu, Wenlong; Fu, Baihe; Wu, Hongjun; Zhang, Zhonghai

    2017-01-15

    For implementing sensitive and selective detection of biological molecules, the biosensors are been designed more and more complicated. The exploration of detection platform in a simple way without loss their sensitivity and selectivity is always a big challenge. Herein, a prototype of recognition biomolecule unit-free photoelectrochemical (PEC) sensing platform with self-cleaning activity is proposed with TiO2 nanotube photonic crystal (TiO2 NTPCs) materials as photoelectrode, and dopamine (DA) molecule as both sensitizer and target analyte. The unique adsorption between DA and TiO2 NTPCs induces the formation of charge transfer complex, which not only expends the optical absorption of TiO2 into visible light region, thus significantly boosts the PEC performance under illumination of visible light, but also implements the selective detection of DA on TiO2 photoelectrode. This simple but efficient PEC analysis platform presents a low detection limit of 0.15nm for detection of DA, which allows to realize the sensitive and selective determination of DA release from the mouse brain for its practical application after coupled with a microdialysis probe. The DA functionalized TiO2 NTPCs PEC sensing platform opens up a new PEC detection model, without using extra-biomolecule auxiliary, just with target molecule naturally adsorbed on the electrode for sensitive and selective detection, and paves a new avenue for biosensors design with minimalism idea.

  10. Printing graphene-carbon nanotube-ionic liquid gel on graphene paper: Towards flexible electrodes with efficient loading of PtAu alloy nanoparticles for electrochemical sensing of blood glucose.

    Science.gov (United States)

    He, Wenshan; Sun, Yimin; Xi, Jiangbo; Abdurhman, Abduraouf Alamer Mohamed; Ren, Jinghua; Duan, Hongwei

    2016-01-15

    The increasing demands for portable, wearable, and implantable sensing devices have stimulated growing interest in innovative electrode materials. In this work, we have demonstrated that printing a conductive ink formulated by blending three-dimensional (3D) porous graphene-carbon nanotube (CNT) assembly with ionic liquid (IL) on two-dimensional (2D) graphene paper (GP), leads to a freestanding GP supported graphene-CNT-IL nanocomposite (graphene-CNT-IL/GP). The incorporation of highly conductive CNTs into graphene assembly effectively increases its surface area and improves its electrical and mechanical properties. The graphene-CNT-IL/GP, as freestanding and flexible substrates, allows for efficient loading of PtAu alloy nanoparticles by means of ultrasonic-electrochemical deposition. Owing to the synergistic effect of PtAu alloy nanoparticles, 3D porous graphene-CNT scaffold, IL binder and 2D flexible GP substrate, the resultant lightweight nanohybrid paper electrode exhibits excellent sensing performances in nonenzymatic electrochemical detection of glucose in terms of sensitivity, selectivity, reproducibility and mechanical properties.

  11. XNBR-grafted halloysite nanotube core-shell as a potential compatibilizer for immiscible polymer systems

    Energy Technology Data Exchange (ETDEWEB)

    Paran, S.M.R.; Naderi, G., E-mail: g.naderi@ippi.ac.ir; Ghoreishy, M.H.R.

    2016-09-30

    Highlights: • Attached an utilitarian silane coupling agent to the HNT via a sol-gel method. • Developed and analyzed the HNT/XNBR core-shell particles via sol-gel technique. • Enhanced the reactivity of the surface of HNT through XNBR grafting. • The act of HNT/XNBR as a compatibilizer in PA6/NBR TPEs. • Immiscible Polymer System with a good balanced physical and mechanical properties. - Abstract: Halloysite nanotubes (HNTs) grafted with carboxylated nitrile byutadiene rubber (XNBR) were synthesized via a sol-gel method. The HNTs as an inorganic cores were pre-treated with 3-Glycidoxypropyl trimethoxysilane, then successfully coated with the XNBR as an organic shell. The properties of XNBR-grafted HNTs were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results suggested that the XNBR grafted to the surfaces of HNTs successfully. Then the TPE nanocomposites based on polyamide-6 (PA6) and nitrile butadiene rubber (NBR) containing various XNBR-grafted and pristine HNTs were prepared via a direct melt mixing method. The morphology, mechanical, dynamic mechanical and rheological properties of the prepared TPE nanocomposites were investigated. The results show that the XNBR-grafted HNTs can effectively improve the morphology and mechanical properties of the PA6/NBR TPEs. The morphology study of the prepared nanocomposites show that the effect of XNBR-grafted HNTs on the size reduction of NBR phase is markedly more effective than the pristine HNTs and rose by 50% in the same concentrations. Mechanical measurements show that the Young’s modulus of the TPE nanocomposites rose by 60% in just 7 wt% of XNBR-grafted HNT loading. The results indicate that the introduction of HNT/XNBR core-shells into the PA6/NBR TPEs can enhances the interfacial interactions

  12. Soft-Sensing Method of Water Temperature Measurement for Controlled Cooling System

    Institute of Scientific and Technical Information of China (English)

    CAI Xiao-hui; ZHANG Dian-hua; WANG Guo-dong; LIU Xiang-hua; FAN Lei

    2003-01-01

    Aiming at the water temperature measuring problem for controlled cooling system of rolling plant, a new water temperature measuring method based on soft-sensing method with a water temperature model of on-line self correction parameter was built. A water temperature compensation factor model was also built to improve coiling temperature control precision. It was proved that the model meets production requirements. The soft-sensing technique has extensive applications in the field of metal forming.

  13. Reaction Force/Torque Sensing in a Master-Slave Robot System without Mechanical Sensors

    Directory of Open Access Journals (Sweden)

    Kyoko Shibata

    2010-07-01

    Full Text Available In human-robot cooperative control systems, force feedback is often necessary in order to achieve high precision and high stability. Usually, traditional robot assistant systems implement force feedback using force/torque sensors. However, it is difficult to directly mount a mechanical force sensor on some working terminals, such as in applications of minimally invasive robotic surgery, micromanipulation, or in working environments exposed to radiation or high temperature. We propose a novel force sensing mechanism for implementing force feedback in a master-slave robot system with no mechanical sensors. The system consists of two identical electro-motors with the master motor powering the slave motor to interact with the environment. A bimanual coordinated training platform using the new force sensing mechanism was developed and the system was verified in experiments. Results confirm that the proposed mechanism is capable of achieving bilateral force sensing and mirror-image movements of two terminals in two reverse control directions.

  14. Architecture and Characteristics of Bacterial Nanotubes.

    Science.gov (United States)

    Dubey, Gyanendra P; Malli Mohan, Ganesh Babu; Dubrovsky, Anna; Amen, Triana; Tsipshtein, Shai; Rouvinski, Alex; Rosenberg, Alex; Kaganovich, Daniel; Sherman, Eilon; Medalia, Ohad; Ben-Yehuda, Sigal

    2016-02-22

    Bacteria display an array of contact-dependent interaction systems that have evolved to facilitate direct cell-to-cell communication. We have previously identified a mode of bacterial communication mediated by nanotubes bridging neighboring cells. Here, we elucidate nanotube architecture, dynamics, and molecular components. Utilizing Bacillus subtilis as a model organism, we found that at low cell density, nanotubes exhibit remarkable complexity, existing as both intercellular tubes and extending tubes, with the latter frequently surrounding the cells in a "root-like" fashion. Observing nanotube formation in real time showed that these structures are formed in the course of minutes, displaying rapid movements. Utilizing a combination of super-resolution, light, and electron microscopy, we revealed that nanotubes are composed of chains of membranous segments harboring a continuous lumen. Furthermore, we discovered that a conserved calcineurin-like protein, YmdB, presents in nanotubes and is required for both nanotube production and intercellular molecular trade.

  15. Simulation of Peak Flows Using Remote Sensing Systems

    Science.gov (United States)

    Magaña Hernández, F.; Ba, K. M.; Guerra-Cobián, V.

    2013-05-01

    In this study we utilized remotely sensed data (radar and satellite precipitation products) to simulate the peak discharges of some storm events of the Escondido River. This is a poorly gauged watershed located in Northern Mexico, in the State of Coahuila and is a sub-basin of Rio Bravo, known also as Río Grande. The radar data are from NOAA (Radar KDFX located in Laughlin Air Force Base, Texas). We used two satellite product estimates PERSIANN and CMORPH. These three estimated precipitation products have been compared using the hydrologic model HEC-HMS to simulate the peak discharge. The results of the simulations show the importance of the use of this type of data in hydrologic modeling.

  16. System and Method for Null-Lens Wavefront Sensing

    Science.gov (United States)

    Hill, Peter C. (Inventor); Thompson, Patrick L. (Inventor); Aronstein, David L. (Inventor); Bolcar, Matthew R. (Inventor); Smith, Jeffrey S. (Inventor)

    2015-01-01

    A method of measuring aberrations in a null-lens including assembly and alignment aberrations. The null-lens may be used for measuring aberrations in an aspheric optic with the null-lens. Light propagates from the aspheric optic location through the null-lens, while sweeping a detector through the null-lens focal plane. Image data being is collected at locations about said focal plane. Light is simulated propagating to the collection locations for each collected image. Null-lens aberrations may extracted, e.g., applying image-based wavefront-sensing to collected images and simulation results. The null-lens aberrations improve accuracy in measuring aspheric optic aberrations.

  17. Preparation of electrochemically reduced graphene oxide/multi-wall carbon nanotubes hybrid film modified electrode, and its application to amperometric sensing of rutin

    Indian Academy of Sciences (India)

    Uling Yang; Gang Li; Meifang Hu; Lingbo Qu

    2014-07-01

    Through a facile electrochemical method, we prepared an electrochemically reduced graphene oxide (ERGO)/multi-wall carbon nanotubes (MWNTs) hybrid film modified glassy carbon electrode (GCE), and characterized it by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and x-ray diffraction (XRD) The experimental results demonstrated that ERGO-MWNTs/GCE exhibited excellent electrocatalytic activity toward rutin as evidenced by the significant enhancement of redox peak currents in comparison with a bare GCE, ERGO/GCE and MWNTs/GCE. This method has been applied for the direct determination of rutin in real samples with satisfactory results.

  18. Novel Platform Development Using an Assembly of Carbon Nanotube, Nanogold and Immobilized RNA Capture Element Towards Rapid, Selective Sensing of Bacteria

    Science.gov (United States)

    2012-06-12

    inoculated by the addition of 10 μL of frozen stock solution to 6 mL of sterile Luria Bertani (LB) broth, comprised of 20 g of powder dissolved in 1 L of...unbound particles. The cellular pellet was suspended in sterile water for UV-Vis measurements. One milliliter of the sample is placed in a quartz...Thordarson, P.; Gooding, J.J.; Ringer, S.P.; Braet, F. Carbon nanotubes for biological and biomedical applications. Nanotechnology 2007, 18, 1–12. 4

  19. Remote sensing application system for water environments developed for Environment Satellite 1

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Remote sensing data collected by the Environment Satellite I are characterized by high temporal resolution,high spectral resolution and mid-high spatial resolution.We designed the Remote Sensing Application System for Water Environments(RSASWE) to create an integrated platform for remote sensing data processing,parameter information extraction and thematic mapping using both remote sensing and GIS technologies.This system provides support for regional water environmental monitoring,and prediction and warning of water pollution.Developed to process and apply data collected by Environment Satellite I,this system has automated procedures including clipping,observation geometry computation,radiometric calibration,6S atmospheric correction and water quality parameter inversion.RSASWE consists of six subsystems:remote sensing image processing,basic parameter inversion,water environment remote sensing thematic outputs,application outputs,automated water environment outputs and a non-point source pollution monitoring subsystem.At present RSASWE plays an important role in operations at the Satellite Environment Center.

  20. Induced electric fields and plasmonic interactions between a metallic nanotube and a thin metallic film

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    We have numerically simulated the induced electric fields and the plasmonic interactions of a metallic nanotube near a thin metallic film. Our study shows that the energies and intensities of the plasmon resonances depend strongly on the aspect ratio (the ratio of the inner to outer radius) of the nanotube as well as the separation between the center of the nanotube and the upper surface of the metallic film and the thickness of the film. The enhancement of the induced electric field of this system reaches as high as 10 4 orders of magnitude and its field distribution is characterized by waveguide-mode resonance. The report proposes that these phenomena can be applied to designing surface enhanced spectroscopies such as surface enhanced Raman spectroscopy for efficient chemical and biological sensing.

  1. Physicochemical characterisation and investigation of the bonding mechanisms of API-titanate nanotube composites as new drug carrier systems.

    Science.gov (United States)

    Sipos, Barbara; Pintye-Hódi, Klára; Kónya, Zoltán; Kelemen, András; Regdon, Géza; Sovány, Tamás

    2017-02-25

    Titanate nanotube (TNT) has recently been explored as a new carrier material for active pharmaceutical ingredients (API). The aim of the present work was to reveal the physicochemical properties of API-TNT composites, focusing on the interactions between the TNTs and the incorporated APIs. Drugs belonging to different Biopharmaceutical Classification System (BCS) classes were loaded into TNTs: diltiazem hydrochloride (BCS I.), diclofenac sodium (BCS II.), atenolol (BCS III.) and hydrochlorothiazide (BCS IV.). Experimental results demonstrated that it is feasible for spiral cross-sectioned titanate nanotubes to carry drugs and maintain their bioactivity. The structural properties of the composites were characterized by a range of analytical techniques, including FT-IR, DSC, TG-MS, etc. The interactions between APIs and TNTs were identified as electrostatic attractions, mainly dominated by hydrogen bonds. Based on the results, it can be stated that the strength of the association depends on the hydrogen donor strength of the API. The drug release of incorporated APIs was evaluated from compressed tablets and compared to that of pure APIs. Differences noticed in the dissolution profiles due to incorporation showed a correlation with the strength of interactions between the APIs and the TNTs observed in the above analytical studies. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Carbon Nanotubes and Modern Nanoagriculture

    KAUST Repository

    Bayoumi, Maged Fouad

    2015-01-27

    Since their discovery, carbon nanotubes have been prominent members of the nanomaterial family. Owing to their extraordinary physical, chemical, and mechanical properties, carbon nanotubes have been proven to be a useful tool in the field of plant science. They were frequently perceived to bring about valuable biotechnological and agricultural applications that still remain beyond experimental realization. An increasing number of studies have demonstrated the ability of carbon nanotubes to traverse different plant cell barriers. These studies, also, assessed the toxicity and environmental impacts of these nanomaterials. The knowledge provided by these studies is of practical and fundamental importance for diverse applications including intracellular labeling and imaging, genetic transformation, and for enhancing our knowledge of plant cell biology. Although different types of nanoparticles have been found to activate physiological processes in plants, carbon nanotubes received particular interest. Following addition to germination medium, carbon nanotubes enhanced root growth and elongation of some plants such as onion, cucumber and rye-grass. They, also, modulated the expression of some genes that are essential for cell division and plant development. In addition, multi-walled carbon nanotubes were evidenced to penetrate thick seed coats, stimulate germination, and to enhance growth of young tomato seedlings. Multi-walled carbon nanotubes can penetrate deeply into the root system and further distribute into the leaves and the fruits. In recent studies, carbon nanotubes were reported to be chemically entrapped into the structure of plant tracheary elements. This should activate studies in the fields of plant defense and wood engineering. Although, all of these effects on plant physiology and plant developmental biology have not been fully understood, the valuable findings promises more research activity in the near future toward complete scientific understanding of

  3. A system-on-chip and paper-based inkjet printed electrodes for a hybrid wearable bio-sensing system.

    Science.gov (United States)

    Xie, Li; Yang, Geng; Mäntysalo, Matti; Jonsson, Fredrik; Zheng, Li-Rong

    2012-01-01

    This paper presents a hybrid wearable bio-sensing system, which combines traditional small-area low-power and high-performance System-on-Chip (SoC), flexible paper substrate and cost-effective Printed Electronics. Differential bio-signals are measured, digitized, stored and transmitted by the SoC. The total area of the chip is 1.5 × 3.0 mm(2). This enables the miniaturization of the wearable system. The electrodes and interconnects are inkjet printed on paper substrate and the performance is verified in in-vivo tests. The quality of electrocardiogram signal sensed by printed electrodes is comparable with commercial electrodes, with noise level slightly increased. The paper-based inkjet printed system is flexible, light and thin, which makes the final system comfortable for end-users. The hybrid bio-sensing system offers a potential solution to the next generation wearable healthcare technology.

  4. Glassy carbon electrode modified with horse radish peroxidase/organic nucleophilic-functionalized carbon nanotube composite for enhanced electrocatalytic oxidation and efficient voltammetric sensing of levodopa.

    Science.gov (United States)

    Shoja, Yalda; Rafati, Amir Abbas; Ghodsi, Javad

    2016-01-01

    A novel and selective enzymatic biosensor was designed and constructed for voltammetric determination of levodopa (L-Dopa) in aqueous media (phosphate buffer solution, pH=7). Biosensor development was on the basis of to physically immobilizing of horse radish peroxidase (HRP) as electrochemical catalyst by sol-gel on glassy carbon electrode modified with organic nucleophilic carbon nanotube composite which in this composite p-phenylenediamine (pPDA) as organic nucleophile chemically bonded with functionalized MWCNT (MWCNT-COOH). The results of this study suggest that prepared bioorganic nucleophilic carbon nanotube composite (HRP/MWCNT-pPDA) shows fast electron transfer rate for electro oxidation of L-Dopa because of its high electrochemical catalytic activity toward the oxidation of L-Dopa, more--NH2 reactive sites and large effective surface area. Also in this work we measured L-Dopa in the presence of folic acid and uric acid as interferences. The proposed biosensor was characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), FT-IR spectroscopy and cyclic voltammetry (CV). The differential pulse voltammetry (DPV) was used for determination of L-Dopa from 0.1 μM to 1.9 μM with a low detection limit of 40 nM (for S/N=3) and sensitivity was about 35.5 μA/μM. Also this biosensor has several advantages such as rapid response, high stability and reproducibility.

  5. Remote sensing of moisture and nutrient stress in turfgrass systems

    Science.gov (United States)

    Kruse, Jason Keith

    Management of irrigation and fertility on a golf course or other large turfgrass area requires a significant amount of time scouting for and identifying problem areas to maintain optimum turfgrass quality. The objectives of these studies were to evaluate the relationship between remotely sensed reflectance data collected from a turfgrass canopy and the associated phosphorus and nitrogen content of turfgrass tissue, and to determine the relationship between reflectance data and soil moisture content as determined by time domain reflectometry (TDR). Phosphorus deficiency symptoms decreased and biomass production increased at P rates above 1.0 g m-2 with a single application while no increase in soil-P was observed. Reflectance measurements were taken in increments from 400 to 1050 nm and correlated with plant tissue P concentration, chlorophyll content, plant biomass and visual quality. Stepwise regression identified a model utilizing reflectance in the blue, yellow, orange, and red regions of the spectrum that explained 73% of the variability in plant tissue P concentration for all sampling dates in 2002 and 2003. Few correlations were found between vegetative indices such as the normalized difference vegetation index (NDVI) and plant response. Results indicate that P deficiencies of creeping bentgrass can be detected through the use of remote sensing. P deficiencies were corrected with a single foliar application of P at rates above 1.5 g m-2. Using partial least-squares regression, our results indicate a weak relationship between the actual and predicted values for turfgrass quality, biomass production, and chlorophyll content under varying rates of N fertilization. However, a strong relationship was observed between actual and predicted values for N concentration of the plant tissue during 2002 and 2003 (r2 = 0.90 and 0.74 respectively). Similarly, no correlation was observed between visual drought stress ratings and the associated soil moisture content for

  6. Inland and coastal water environment remote sensing monitoring system: rapid construction and application

    Science.gov (United States)

    Xu, Hua; Gu, Xingfa; Yin, Qiu; Li, Li; Chen, Qiang; Ren, Yuhuan; Chen, Hong; Liu, Xudong; Zhang, Juan

    2009-10-01

    This paper aims at bridging the gap between the academic research and practical application in water environment monitoring by remote sensing. It mainly focuses on how to rapidly construct the Inland and coastal Water Environment Remote Sensing Monitoring System (IWERSMS) in a software perspective. In this paper, the remote sensed data processing framework, dataflow and product levels are designed based on the retrieval algorithms of water quality parameters. The prototype is four-tier architecture and modules are designed elaborately. The paper subsequently analyzes the strategy and key technology of conglutinating hybrid components, adopting semantic metafiles and tiling image during rapid construction of prototype. Finally, the paper introduces the successful application to 2008 Qingdao enteromorpha prolifra disaster emergency monitoring in Olympics Sailing Match fields. The solution can also fit other domains in remote sensing and especially it provides a clue for researchers who are in an attempt to establish a prototype to apply research fruits to practical applications.

  7. Oxidized multiwalled carbon nanotubes as antigen delivery system to promote superior CD8(+) T cell response and protection against cancer.

    Science.gov (United States)

    de Faria, Paula Cristina Batista; dos Santos, Luara Isabela; Coelho, João Paulo; Ribeiro, Henrique Bücker; Pimenta, Marcos Assunção; Ladeira, Luiz Orlando; Gomes, Dawidson Assis; Furtado, Clascídia Aparecida; Gazzinelli, Ricardo Tostes

    2014-09-10

    Properties like high interfacial area with cellular membranes, unique ability to incorporate multiple functionalization, as well as compatibility and transport in biological fluids make carbon nanotubes (CNTs) useful for a variety of therapeutic and drug-delivery applications. Here we used a totally synthetic hybrid supramolecule as an anticancer vaccine formulation. This complex structure comprises CNTs as delivery system for the Cancer Testis Antigen named NY-ESO-1, allied to a synthetic Toll-Like Receptor agonist. The CNT constructs were rapidly internalized into dendritic cells, both in vitro and in vivo, and served as an intracellular antigen depot. This property favored the induction of strong CD4(+) T as well as CD8(+) T cell-mediated immune responses against the NY-ESO-1. Importantly, the vaccination significantly delayed the tumor development and prolonged the mice survival, highlighting the potential application of CNTs as a vaccine delivery system to provide superior immunogenicity and strong protection against cancer.

  8. Nickel Sulfide/Graphene/Carbon Nanotube Composites as Electrode Material for the Supercapacitor Application in the Sea Flashing Signal System

    Institute of Scientific and Technical Information of China (English)

    Hailong Chen; Ji Li; Conglai Long; Tong Wei; Guoqing Ning; Jun Yan; Zhuangjun Fan

    2014-01-01

    This work presents NiS/graphene/carbon nanotube (NiS/GNS/CNT) composites as electrode material for the supercapacitor application in sea flashing signal systems. NiS nanosheets were closely anchored on the conductive GNS-CNT networks. As a result, the NiS/GNS/CNT electrode showed a high specific capacitance of 2 377 F·g-1 at 2 mV·s-1 and good cycling stability compared with the pure NiS (1 599 F·g-1 ). The enhanced electrochemical performances are attributed to the synergetic effect between the conductive carbon and the pseudo-capacitive NiS. The high performance supercapacitor may provide application in the sea flashing signal system.

  9. Combination of Polymer Technology and Carbon Nanotube Array for the Development of an Effective Drug Delivery System at Cellular Level

    Directory of Open Access Journals (Sweden)

    Riggio Cristina

    2009-01-01

    Full Text Available Abstract In this article, a carbon nanotube (CNT array-based system combined with a polymer thin film is proposed as an effective drug release device directly at cellular level. The polymeric film embedded in the CNT array is described and characterized in terms of release kinetics, while in vitro assays on PC12 cell line have been performed in order to assess the efficiency and functionality of the entrapped agent (neural growth factor, NGF. PC12 cell differentiation, following incubation on the CNT array embedding the alginate delivery film, demonstrated the effectiveness of the proposed solution. The achieved results indicate that polymeric technology could be efficiently embedded in CNT array acting as drug delivery system at cellular level. The implication of this study opens several perspectives in particular in the field of neurointerfaces, combining several functions into a single platform.

  10. Pharmacia and biological functionalities of nutrient broth dispersed multi-walled carbon nanotubes:A novel drug delivery system

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A new drug delivery system was developed using the interaction of nutrient broth treated multi-walled carbon nanotubes(NBT-MWCNTs) and cefotaxime sodium(CTX) as a model.Investigated factors of the drug delivery system include dispersion effect,biocompatibility of NBT-MWCNTs,pharmacodynamic effect and delivery efficiency in vitro.It was found that MWCNTs can be well dispersed in the nutrient broth and stable at least for one week at 4 °C.The formed NBT-MWCNTs suspension scarcely exhibits toxicity to E.coli at concentrations lower than 10.24 μg/mL,but displays enhanced pharmacodynamic effect of CTX via its bridge effect and targeted transport.Compared with general acid treated MWCNTs(AT-MWCNTs),our present NBT-MWCNTs show good biocompatibility,enhanced pharmacodynamic effect,and high delivery efficiency.

  11. Rotating Casimir systems: magnetic-field-enhanced perpetual motion, possible realization in doped nanotubes, and laws of thermodynamics

    CERN Document Server

    Chernodub, M N

    2012-01-01

    Recently, we have demonstrated that for a certain class of Casimir-type systems ("devices") the energy of zero-point vacuum fluctuations reaches its global minimum when the device rotates about certain axis rather than remains static. This rotational vacuum effect may lead to emergence of permanently rotating objects - philosophically similar to "time crystals" proposed recently by Shapere and Wilczek in classical and quantum mechanical systems - provided the negative rotational energy of zero-point fluctuations cancels the positive rotational energy of the device itself. In this paper we show that for massless electrically charged particles the rotational vacuum effect should be drastically (astronomically) enhanced in the presence of magnetic field. As an illustration, we show that in a background of experimentally available magnetic fields the zero-point energy of massless excitations in rotating torus-shaped doped carbon nanotubes may indeed overwhelm the classical energy of rotation for certain angular f...

  12. Novel electrode systems for amperometric sensing: the case of titanium

    Science.gov (United States)

    Terzi, F.; Pigani, L.; Zanardi, C.; Zanfrognini, B.; Ruggeri, S.; Maccaferri, G.; Seeber, R.

    2014-10-01

    After working for years on organic materials, e.g., polythiophenes and relevant composites with metal nanoparticles, we shifted our attention to unusual metals, chosen as candidates to effective amperometric sensing on the basis of the atomic structure and crystalline properties. The present contribution aims at proposing an electrode material rarely employed in electroanalysis, namely Ti. We have experimented that the peculiar nature of Ti leads to electrochemical behavior quite different with respect to the conventional electrode materials, including those based on TiO2 (nano)particles. Our work focuses on the determination of strong oxidizing species, namely H2O2 and HClO, and noble metal ions, namely Au(III). Strong oxidizing species are commodity chemicals employed in a number of different industrial processes, in which usually high concentration levels should be monitored. The procedures proposed have been successfully applied also in complex matrices, such as detergent samples. As to Au(III) determination, it also constitutes a crucial tool in order to increase the efficiency of hydrometallurgic processes and of the recovery of precious materials from electronic waste. Ti electrodes allow the determination of dissolved Au species in the presence of other metal ions. In any cases the electrodes exhibit reproducible and repeatable electrochemical responses, even in the presence of high concentration of organic fouling species typical of bio-sorption processes.

  13. A biomimetic tactile sensing system based on polyvinylidene fluoride film

    Science.gov (United States)

    Xin, Yi; Tian, Hongying; Guo, Chao; Li, Xiang; Sun, Hongshuai; Wang, Peiyuan; Qian, Chenghui; Wang, Shuhong; Wang, Cheng

    2016-02-01

    Polyvinylidene fluoride (PVDF) film has been widely investigated as a sensing material due to its outstanding properties such as biocompatibility, high thermal stability, good chemical resistance, high piezo-, pyro- and ferro-electric properties. This paper reports on the design, test, and analysis of a biomimetic tactile sensor based on PVDF film. This sensor consists of a PVDF film with aluminum electrodes, a pair of insulating layers, and a "handprint" friction layer with a copper foil. It is designed for easy fabrication and high reliability in outputting signals. In bionics, the fingerprint of the glabrous skin plays an important role during object handling. Therefore, in order to enhance friction and to provide better manipulation, the ridges of the fingertips were introduced into the design of the proposed tactile sensor. And, a basic experimental study on the selection of the high sensitivity fingerprint type for the biomimetic sensor was performed. In addition, we proposed a texture distinguish experiment to verify the sensor sensitivity. The experiment's results show that the novel biomimetic sensor is effective in discriminating object surface characteristics. Furthermore, an efficient visual application program (LabVIEW) and a quantitative evaluation method were proposed for the verification of the biomimetic sensor. The proposed tactile sensor shows great potential for contact force and slip measurements.

  14. Advanced Fiber Optic-Based Sensing Technology for Unmanned Aircraft Systems

    Science.gov (United States)

    Richards, Lance; Parker, Allen R.; Piazza, Anthony; Ko, William L.; Chan, Patrick; Bakalyar, John

    2011-01-01

    This presentation provides an overview of fiber optic sensing technology development activities performed at NASA Dryden in support of Unmanned Aircraft Systems. Examples of current and previous work are presented in the following categories: algorithm development, system development, instrumentation installation, ground R&D, and flight testing. Examples of current research and development activities are provided.

  15. Small RNA target genes and regulatory connections in the Vibrio cholerae quorum sensing system

    DEFF Research Database (Denmark)

    Hammer, Brian K; Svenningsen, Sine Lo

    2011-01-01

    The two-component quorum sensing (QS) system, first described in the marine bacterium Vibrio harveyi and evolutionarily conserved among members of the genus Vibrio, has been best studied in the human pathogen Vibrio cholerae (1, 2). In the V. cholerae QS system, the response to the accumulation...

  16. Present status and trend of technological developments for millimeter wave sensing systems

    Science.gov (United States)

    Ihara, Toshio; Okamoto, Ken'ichi; Kitamura, Katsumi; Awaka, Jun; Manabe, Takeshi

    1989-06-01

    Millimeter wave atmospheric propagation characteristics and state-of-the-art millimeter wave component technologies are reviewed. Particular attention is given to the current status of technological developments for millimeter wave sensing systems such as automotive radars, automatic location identification systems, and industrial instrumentation radars.

  17. SYNTHESIS OF CARBON NANOTUBES FOR ACETYLENE DETECTION

    Directory of Open Access Journals (Sweden)

    M.Y. FAIZAH

    2008-04-01

    Full Text Available A gas sensor, utilizing carbon nanotubes (CNTs in a pellet form for acetylene detection has been developed. This research was carried out to investigate the absorption effect of acetylene (C2H2 towards the change of resistance of carbon nanotubes pellet as sensor signal. Source Measurement Unit (SMU was used to study the gas sensing behaviour of resistance based sensors employing carbon nanotubes pellet as the active sensing element. Studies revealed that the absorption of acetylene into the carbon nanotubes pellet resulting in increase in pellet resistance. The changes are attributed to p-type conductivity in semiconducting carbon nanotubes. Carbon nanotubes used in this research was synthesized by means of Floating Catalyst Chemical Vapor Deposition (FC-CVD method. Benzene was used as a hydrocarbon source while ferrocene as a source of catalyst with Hydrogen and Argon as carrier and purge gas respectively. From the research, it was shown that carbon nanotubes show high sensitivity towards acetylene. The highest sensitivity recorded was 1.21, 1.16 and 17.86 for S1, S2 and S3 respectively. It is expected that many applications of CNT-based sensors will be explored in future as the interest of the nanotechnology research in this field increases.

  18. Dielectrophoretic assembly of carbon nanotube devices

    DEFF Research Database (Denmark)

    Dimaki, Maria

    The purpose of this project has been to assemble single-walled carbon nanotubes on electrodes at the tip of a biocompatible cantilever and use these for chemical species sensing in air and liquid, for example in order to measure the local activity from ion channels in the cell membrane. The elect......The purpose of this project has been to assemble single-walled carbon nanotubes on electrodes at the tip of a biocompatible cantilever and use these for chemical species sensing in air and liquid, for example in order to measure the local activity from ion channels in the cell membrane....... The electrical resistance of carbon nanotubes has been shown to be extremely sensitive to gas molecules. Dielectrophoresis is a method capable of quickly attracting nanotubes on microelectrodes by using an electric field, thus enabling nanotube integration in microsystems. Dielectrophoresis offers also...... the potential of distinguishing between nanotubes of different electrical properties, which is very important for the optimisation of the properties of the carbon nanotube sensors. Various cantilever and planar structures were designed, fabricated and tested both with multi-walled and single-walled carbon...

  19. Remote Sensing Image Interpretation for Urban Environment Analysis: Methods, System and Examples

    Directory of Open Access Journals (Sweden)

    Peijun Du

    2014-10-01

    Full Text Available Remote sensing imagery has been widely used in urban growth and environment analysis with many effective and advanced strategies being developed. However, most of these approaches are separated from each other. There is an urgent need to combine different modules into some practical processing chains. Firstly, we present a comprehensive analysis of key processing chains in applying remote sensing images to urban environment analysis from such aspects as Land Use/Land Cover (LULC, urban landscape ecology, Urban Heat Islands (UHIs, vegetation and water monitoring, change detection, urban ecological security assessment and urban environmental mapping. Secondly, an integrated system, namely Urban Environment Analysis System (UEAS, is implemented based on the aforementioned processing chains to analyze urban environment using multi-temporal and multi-source remotely sensed data. Several case studies are demonstrated to confirm the effectiveness of the integrated system and the combined processing chains. The contributions of this paper lie in introducing ensemble learning to urban environment remote sensing, combining remote sensing derived information with thematic models for urban environment assessment, and developing an integrated system for urban environment analysis.

  20. Linking climate change education through the integration of a kite-borne remote sensing system

    Directory of Open Access Journals (Sweden)

    Yichun Xie

    2014-09-01

    Full Text Available A majority of secondary science teachers are found to include the topic of climate change in their courses. However, teachers informally and sporadically discuss climate change and students rarely understand the underlying scientific concepts. The project team developed an innovative pedagogical approach, in which teachers and students learn climate change concepts by analyzing National Aeronautics and Space Administration (NASA global data collected through satellites and by imitating the NASA data collection process through NASA Airborne Earth Research Observation Kites And Tethered Systems (AEROKATS, a kite-borne remote sensing system. Besides AEROKATS, other major components of this system include a web-collection of NASA and remote sensing data and related educational resources, project-based learning for teacher professional development, teacher and student field trips, iOS devices, smart field data collector apps, portable weather stations, probeware, and a virtual teacher collaboratory supported with a GIS-enabled mapping portal. Three sets of research instruments, the NASA Long-Term Experience –Educator End of Event Survey, the Teacher End of Project Survey, and the pre-and-post-Investigating Climate Change and Remote Sensing (ICCARS project student exams, are adapted to study the pedagogical impacts of the NASA AEROKATS remote sensing system. These findings confirm that climate change education is more effective when both teachers and students actively participate in authentic scientific inquiry by collecting and analyzing remote sensing data, developing hypotheses, designing experiments, sharing findings, and discussing results.

  1. Cross layers decision making and fusion model in layered sensing systems

    Science.gov (United States)

    Khoshnaw, Abdulqadir; Zein-Sabatto, Saleh; Malkani, Mohan

    2012-06-01

    Layered sensing systems involve operation of several layers of sensing with different capabilities integrated into one whole system. The integrated layers of sensing must share information and local decisions across layers for better situation awareness. This research focused on the development of a model for decision making and fusion at the information level in layered sensing systems using the cloud model for uncertainty processing. In this research, the addition of a new processing level to the Joint Directors of Laboratories (JDL) processing model is proposed. The new processing level is called "Information Assessment, Fusion, and Control (IAFC)". Through this level, the different layers of a layered sensing system evaluate information about a given situation in terms of threat level and make a decision. The information assessment and control processing module were able to assess the threat level of a situation accurately and exchange assessments in order to determine the overall situation's threat level among all layers. The uncertain decisions were fused together to a unified decision using the cloud model of uncertainty processing methodology. Using this methodology, a cognitive element was added to the process of information assessment module leading to more accurate situation awareness.

  2. Development of a tactile sensing system using piezoelectric robot skin materials

    Science.gov (United States)

    Hwang, S. K.; Hwang, H. Y.

    2013-05-01

    Since service robots perform their functions in close proximity to humans, they are much more likely than other types of robot to come into contact with humans. This means that safety regarding robot-human interaction is of particular concern and requires investigation. Existing tactile sensing methods are very effective at detecting external dangerous loadings; however, until now, they have been very expensive. Recently, a new type of self-sensing tactile technology for service robots has been introduced, which harnesses the piezoelectric effect of several robot skin materials. In these kinds of system, relatively cheap materials are used as sensors themselves. In this research, a robot system with a self-sensing tactile technology was developed using piezoelectric robot skin materials. The test results indicate that this type of system is appropriate for application to service robots.

  3. Commercialization of the land remote sensing system: An examination of mechanisms and issues

    Science.gov (United States)

    Cauley, J. K.; Gaelick, C.; Greenberg, J. S.; Logsdon, J.; Monk, T.

    1983-01-01

    In September 1982 the Secretary of Commerce was authorized (by Title II of H.R. 5890 of the 97th Congress) to plan and provide for the management and operation of the civil land remote sensing satellite systems, to provide for user fees, and to plan for the transfer of the ownership and operation of future civil operational land remote sensing satellite systems to the private sector. As part of the planning for transfer, a number of approaches were to be compared including wholly private ownership and operation of the system by an entity competitively selected, mixed government/private ownership and operation, and a legislatively-chartered privately-owned corporation. The results of an analysis and comparison of a limited number of financial and organizational approaches for either transfer of the ownership and operation of the civil operational land remote sensing program to the private sector or government retention are presented.

  4. Development of a Cost-Effective Airborne Remote Sensing System for Coastal Monitoring

    Directory of Open Access Journals (Sweden)

    Duk-jin Kim

    2015-09-01

    Full Text Available Coastal lands and nearshore marine areas are productive and rapidly changing places. However, these areas face many environmental challenges related to climate change and human-induced impacts. Space-borne remote sensing systems may be restricted in monitoring these areas because of their spatial and temporal resolutions. In situ measurements are also constrained from accessing the area and obtaining wide-coverage data. In these respects, airborne remote sensing sensors could be the most appropriate tools for monitoring these coastal areas. In this study, a cost-effective airborne remote sensing system with synthetic aperture radar and thermal infrared sensors was implemented to survey coastal areas. Calibration techniques and geophysical model algorithms were developed for the airborne system to observe the topography of intertidal flats, coastal sea surface current, sea surface temperature, and submarine groundwater discharge.

  5. Hard Decision Fusion based Cooperative Spectrum Sensing in Cognitive Radio System

    Directory of Open Access Journals (Sweden)

    N. Armi N.M. Saad

    2013-09-01

    Full Text Available Cooperative spectrum sensing was proposed to combat fading, noise uncertainty, shadowing, and even hidden node problem due to primary users (PUs activity that is not spatially localized. It improves the probability of detection by collaborating to detect PUs signal in cognitive radio (CR system as well. This paper studies cooperative spectrum sensing and signal detection in CR system by implementing hard decision combining in data fusion centre. Through computer simulation, we evaluate the performances of cooperative spectrum sensing and signal detection by employing OR and AND rules as decision combining. Energy detector is used to observe the presence of primary user (PU signal. Those results are compared to non-cooperative signal detection for evaluation. They show that cooperative technique has better performance than non-cooperative. Moreover, signal to noise ratio (SNR with greater than or equal 10 dB and 15 collaborated users in CR system has optimal value for probability of detection.

  6. CellSense: An Accurate Energy-Efficient GSM Positioning System

    CERN Document Server

    Ibrahim, Mohamed

    2011-01-01

    Context-aware applications have been gaining huge interest in the last few years. With cell phones becoming ubiquitous computing devices, cell phone localization has become an important research problem. In this paper, we present CellSense, a prob- abilistic RSSI-based fingerprinting location determi- nation system for GSM phones. We discuss the chal- lenges of implementing a probabilistic fingerprinting localization technique in GSM networks and present the details of the CellSense systemand how it addresses these challenges. We then extend the proposed system using a hybrid technique that combines probabilistic and deterministic estimation to achieve both high ac- curacy and low computational overhead.Moreover, the accuracy of the hybrid technique is robust to changes in its parameter values. To evaluate our proposed system, we implemented CellSense on Android-based phones. Results from two different testbeds, represent- ing urban and rural environments, for three differ- ent cellular providers show that Ce...

  7. Programmable performance - One aspect of smart sensing systems

    Science.gov (United States)

    Jobson, D. J.

    1980-01-01

    Programmable performance is the ability to flexibly alter basic spatial, spectral, and radiometric system response as a function of time. In this paper programmable performance is defined as a functional element of smart sensor systems for the 1990's. The uses and benefits of these classes of sensor systems are discussed with reference to multispectral scanners of the earth's surface. An overall technology trend is identified which couples a high degree of sensor performance flexibility to a need for advanced device technology developments.

  8. Spacesuit Sensing Data Display and Management System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ZIN Technologies, Inc will breadboard an integrated electronic system for space suit application to acquire images, biomedical sensor signals and suit health &...

  9. Multiscale Modeling with Carbon Nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Maiti, A

    2006-02-21

    Technologically important nanomaterials come in all shapes and sizes. They can range from small molecules to complex composites and mixtures. Depending upon the spatial dimensions of the system and properties under investigation computer modeling of such materials can range from equilibrium and nonequilibrium Quantum Mechanics, to force-field-based Molecular Mechanics and kinetic Monte Carlo, to Mesoscale simulation of evolving morphology, to Finite-Element computation of physical properties. This brief review illustrates some of the above modeling techniques through a number of recent applications with carbon nanotubes: nano electromechanical sensors (NEMS), chemical sensors, metal-nanotube contacts, and polymer-nanotube composites.

  10. Development of Novel Magnetic Metal Oxide Thin Films and Carbon Nanotube Materials for Potential Device Applications

    Science.gov (United States)

    2016-05-09

    materials with applications in areas such as magnetic recording, magnetic sensing devices and high frequency planar microwave devices. Emphasis has been... emission SEM/STEM. For STEM imaging, some nanotubes were scrapped off SiO2 substrate and dispersed in dimethylformamide the resulting solution was dripped...on holey carbon coated carbon TEM grid for SEM and STEM analysis. VSM measurements were carried out using Vector Magnetometer Model 10 VSM system

  11. Epitaxial Approaches to Carbon Nanotube Organization

    Science.gov (United States)

    Ismach, Ariel

    Carbon nanotubes have unique electronic, mechanical, optical and thermal properties, which make them ideal candidates as building blocks in nano-electronic and electromechanical systems. However, their organization into well-defined geometries and arrays on surfaces remains a critical challenge for their integration into functional nanosystems. In my PhD, we developed a new approach for the organization of carbon nanotubes directed by crystal surfaces. The principle relies on the guided growth of single-wall carbon nanotubes (SWNTs) by atomic features presented on anisotropic substrates. We identified three different modes of surface-directed growth (or 'nanotube epitaxy'), in which the growth of carbon nanotubes is directed by crystal substrates: We first observed the nanotube unidirectional growth along atomic steps ('ledge-directed epitaxy') and nanofacets ('graphoepitaxy') on the surface of miscut C-plane sapphire and quartz. The orientation along crystallographic directions ('lattice-directed epitaxy') was subsequently observed by other groups on different crystals. We have proposed a "wake growth" mechanism for the nanotube alignment along atomic steps and nanofacets. In this mechanism, the catalyst nanoparticle slides along the step or facet, leaving the nanotube behind as a wake. In addition, we showed that the combination of surface-directed growth with external forces, such as electric-field and gas flow, can lead to the simultaneous formation of complex nanotube structures, such as grids and serpentines. The "wake growth" model, which explained the growth of aligned nanotubes, could not explain the formation of nanotube serpentines. For the latter, we proposed a "falling spaghetti" mechanism, in which the nanotube first grows by a free-standing process, aligned in the direction of the gas flow, then followed by absorption on the stepped surface in an oscillatory manner, due to the competition between the drag force caused by the gas flow on the suspended

  12. Built-in active sensing diagnostic system for civil infrastructure systems

    Science.gov (United States)

    Wu, Fan; Chang, Fu-Kuo

    2001-07-01

    A reliable, robust monitoring system can improve the maintenance of and provide safety protection for civil structures and therefore prolong their service lives. A built-in, active sensing diagnostic technique for civil structures has been under investigation. In this technique, piezoelectric materials are used as sensors/actuators to receive and generate signals. The transducers are embedded in reinforced concrete (RC) beams and are designed to detect damage, particularly debonding damage between the reinforcing bars and concrete. This paper presents preliminary results from a feasibility study of the technology. Laboratory experiments performed on RC beams, with piezo-electric sensors and actuators mounted on reinforced steel bars, have clearly demonstrated that the proposed technique could detect debonding damage. Analytical work, using a special purpose finite-element software, PZFlex, was also conducted to interpret the relationship between the measured data and actual debonding damage. Effectiveness of the proposed technique for detecting debonding damage in civil structures has been demonstrated.

  13. System-theoretic Interpretation of the Mode Sensing Hypothesis

    Science.gov (United States)

    2014-08-01

    uniqueness of the state-space realisation . . . . . . . . . . . . . . . . . . . 23 7.5 Equitable system energy distribution...distribution is expressed theoretically through the system-theoretic notion of balanced realisation , and is practically important in al- lowing the...absolute values can be equated directly with their disturbance values . Nevertheless, it is important to keep in mind that the kinematic variables which

  14. The Design of Vibration Sensing System Used for the Internet of Things

    Science.gov (United States)

    Ji, Wei; Ma, Xuejie

    2016-06-01

    A vibration sensing system used for the Internet of Things is presented in this paper. Using the distributed feedback fiber lasers (DFB-FL) collects external sound signals and digital phase generated carrier (PGC) method realizes wavelength demodulation. The platform is designed based on an open architecture and B/S (Browser/Server) technology which makes it an ideal platform to be operated under a network environment. The sensing system is no power supply and could be monitored anytime and anywhere which is the requirement of Internet of things.

  15. Variability of the Quorum Sensing System in Natural Isolates of Bacillus sp.

    Directory of Open Access Journals (Sweden)

    Ines Mandic-Mulec

    2003-01-01

    Full Text Available Bacteria communicate with one another by (emitting and/or reacting to chemical signals. These communications, also known as quorum sensing, enable cells to control gene expression in response to cell density at the intra- and inter-species level. While bacteria use common signaling themes, variations in the design of the extracellular signals, the signal detection apparatus, and the biochemical mechanisms of signal relay have allowed quorum sensing systems to be adapted to diverse uses. The quorum sensing systems that govern natural genetic competence in Bacillus subtilis involve the ComX pheromones and the ComP-ComA, two-component regulator. ComX is synthesized as an inactive precursor and is then cleaved and modified by ComQ before export to the extra-cellular environment. The comQXP' loci of a set of natural Bacillus isolates have been sequenced and a striking polymorphism that correlates with specific patterns of activation of the quorum sensing response was shown. The ComX molecules representing different pherotypes were purified and characterized by mass spectroscopy. The analyses revealed that ComX variants also differ at the level of posttranslational modification of a conserved tryptophane residue, which was found to be an isoprenoid. The striking variability found in competence quorum sensing systems might be important for the survival of these bacteria in nature to escape the inappropriate induction of competence by closely related strains, playing the role of a sexual isolation mechanism.

  16. The Global Land Surface Satellite (GLASS Remote Sensing Data Processing System and Products

    Directory of Open Access Journals (Sweden)

    Gongqi Zhou

    2013-05-01

    Full Text Available Using remotely sensed satellite products is the most efficient way to monitor global land, water, and forest resource changes, which are believed to be the main factors for understanding global climate change and its impacts. A reliable remotely sensed product should be retrieved quantitatively through models or statistical methods. However, producing global products requires a complex computing system and massive volumes of multi-sensor and multi-temporal remotely sensed data. This manuscript describes the ground Global LAnd Surface Satellite (GLASS product generation system that can be used to generate long-sequence time series of global land surface data products based on various remotely sensed data. To ensure stabilization and efficiency in running the system, we used the methods of task management, parallelization, and multi I/O channels. An array of GLASS remote sensing products related to global land surface parameters are currently being produced and distributed by the Center for Global Change Data Processing and Analysis at Beijing Normal University in Beijing, China. These products include Leaf Area Index (LAI, land surface albedo, and broadband emissivity (BBE from the years 1981 to 2010, downward shortwave radiation (DSR and photosynthetically active radiation (PAR from the years 2008 to 2010.

  17. Comparative study of the electrochemical behavior and analytical applications of (bio)sensing platforms based on the use of multi-walled carbon nanotubes dispersed in different polymers.

    Science.gov (United States)

    Primo, E N; Gutierrez, F A; Luque, G L; Dalmasso, P R; Gasnier, A; Jalit, Y; Moreno, M; Bracamonte, M V; Rubio, M Eguílaz; Pedano, M L; Rodríguez, M C; Ferreyra, N F; Rubianes, M D; Bollo, S; Rivas, G A

    2013-12-17

    This review present a critical comparison of the electrochemical behavior and analytical performance of glassy carbon electrodes (GCE) modified with carbon nanotubes (CNTs) dispersed in different polymers: polyethylenimine (PEI), PEI functionalized with dopamine (PEI-Do), polyhistidine (Polyhis), polylysine (Polylys), glucose oxidase (GOx) and double stranded calf-thymus DNA (dsDNA). The comparison is focused on the analysis of the influence of the sonication time, solvent, polymer/CNT ratio, and nature of the polymer on the efficiency of the dispersions and on the electrochemical behavior of the resulting modified electrodes. The results allow to conclude that an adequate selection of the polymers makes possible not only an efficient dispersion of CNTs but also, and even more important, the building of successful analytical platforms for the detection of different bioanalytes like NADH, glucose, DNA and dopamine.

  18. Preparation of Surface Adsorbed and Impregnated Multi-walled Carbon Nanotube/Nylon-6 Nanofiber Composites and Investigation of their Gas Sensing Ability.

    Science.gov (United States)

    Lala, Neeta L; Thavasi, Velmurugan; Ramakrishna, Seeram

    2009-01-01

    We have prepared electrospun Nylon-6 nanofibers via electrospinning, and adsorbed multi-walled carbon nanotubes (MWCNTs) onto the surface of Nylon-6 fibers using Triton(®) X-100 to form a MWCNTs/Nylon-6 nanofiber composite. The dispersed MWCNTs have been found to be stable in hexafluoroisopropanol for several months without precipitation. A MWCNTs/Nylon-6 nanofiber composite based chemical sensor has demonstrated its responsiveness towards a wide range of solvent vapours at room temperature and only mg quantities of MWCNTs were expended. The large surface area and porous nature of the electrospun Nylon-6/MWCNT nanofibers facilitates greater analyte permeability. The experimental analysis has indicated that the dipole moment, functional group and vapour pressure of the analytes determine the magnitude of the responsiveness.

  19. Preparation of Surface Adsorbed and Impregnated Multi-walled Carbon Nanotube/Nylon-6 Nanofiber Composites and Investigation of their Gas Sensing Ability

    Directory of Open Access Journals (Sweden)

    Velmurugan Thavasi

    2009-01-01

    Full Text Available We have prepared electrospun Nylon-6 nanofibers via electrospinning, and adsorbed multi-walled carbon nanotubes (MWCNTs onto the surface of Nylon-6 fibers using Triton® X-100 to form a MWCNTs/Nylon-6 nanofiber composite. The dispersed MWCNTs have been found to be stable in hexafluoroisopropanol for several months without precipitation. A MWCNTs/Nylon-6 nanofiber composite based chemical sensor has demonstrated its responsiveness towards a wide range of solvent vapours at room temperature and only mg quantities of MWCNTs were expended. The large surface area and porous nature of the electrospun Nylon-6/MWCNT nanofibers facilitates greater analyte permeability. The experimental analysis has indicated that the dipole moment, functional group and vapour pressure of the analytes determine the magnitude of the responsiveness.

  20. Nanotube cathodes.

    Energy Technology Data Exchange (ETDEWEB)

    Overmyer, Donald L.; Lockner, Thomas Ramsbeck; Siegal, Michael P.; Miller, Paul Albert

    2006-11-01

    Carbon nanotubes have shown promise for applications in many diverse areas of technology. In this report we describe our efforts to develop high-current cathodes from a variety of nanotubes deposited under a variety of conditions. Our goal was to develop a one-inch-diameter cathode capable of emitting 10 amperes of electron current for one second with an applied potential of 50 kV. This combination of current and pulse duration significantly exceeds previously reported nanotube-cathode performance. This project was planned for two years duration. In the first year, we tested the electron-emission characteristics of nanotube arrays fabricated under a variety of conditions. In the second year, we planned to select the best processing conditions, to fabricate larger cathode samples, and to test them on a high-power relativistic electron beam generator. In the first year, much effort was made to control nanotube arrays in terms of nanotube diameter and average spacing apart. When the project began, we believed that nanotubes approximately 10 nm in diameter would yield sufficient electron emission properties, based on the work of others in the field. Therefore, much of our focus was placed on measured field emission from such nanotubes grown on a variety of metallized surfaces and with varying average spacing between individual nanotubes. We easily reproduced the field emission properties typically measured by others from multi-wall carbon nanotube arrays. Interestingly, we did this without having the helpful vertical alignment to enhance emission; our nanotubes were randomly oriented. The good emission was most likely possible due to the improved crystallinity, and therefore, electrical conductivity, of our nanotubes compared to those in the literature. However, toward the end of the project, we learned that while these 10-nm-diameter CNTs had superior crystalline structure to the work of others studying field emission from multi-wall CNT arrays, these nanotubes still

  1. CMOS indoor light energy harvesting system for wireless sensing applications

    CERN Document Server

    Ferreira Carvalho, Carlos Manuel

    2016-01-01

    This book discusses in detail the CMOS implementation of energy harvesting.  The authors describe an integrated, indoor light energy harvesting system, based on a controller circuit that dynamically and automatically adjusts its operation to meet the actual light circumstances of the environment where the system is placed.  The system is intended to power a sensor node, enabling an autonomous wireless sensor network (WSN). Although designed to cope with indoor light levels, the system is also able to work with higher levels, making it an all-round light energy harvesting system.  The discussion includes experimental data obtained from an integrated manufactured prototype, which in conjunction with a photovoltaic (PV) cell, serves as a proof of concept of the desired energy harvesting system.  ·         Discusses several energy sources which can be used to power energy harvesting systems and includes an overview of PV cell technologies  ·         Includes an introduction to voltage step-...

  2. Operational perspective of remote sensing-based forest fire danger forecasting systems

    Science.gov (United States)

    Chowdhury, Ehsan H.; Hassan, Quazi K.

    2015-06-01

    Forest fire is a natural phenomenon in many ecosystems across the world. One of the most important components of forest fire management is the forecasting of fire danger conditions. Here, our aim was to critically analyse the following issues, (i) current operational forest fire danger forecasting systems and their limitations; (ii) remote sensing-based fire danger monitoring systems and usefulness in operational perspective; (iii) remote sensing-based fire danger forecasting systems and their functional implications; and (iv) synergy between operational forecasting systems and remote sensing-based methods. In general, the operational systems use point-based measurements of meteorological variables (e.g., temperature, wind speed and direction, relative humidity, precipitations, cloudiness, solar radiation, etc.) and generate danger maps upon employing interpolation techniques. Theoretically, it is possible to overcome the uncertainty associated with the interpolation techniques by using remote sensing data. During the last several decades, efforts were given to develop fire danger condition systems, which could be broadly classified into two major groups: fire danger monitoring and forecasting systems. Most of the monitoring systems focused on determining the danger during and/or after the period of image acquisition. A limited number of studies were conducted to forecast fire danger conditions, which could be adaptable. Synergy between the operational systems and remote sensing-based methods were investigated in the past but too much complex in nature. Thus, the elaborated understanding about these developments would be worthwhile to advance research in the area of fire danger in the context of making them operational.

  3. Glassy carbon electrode modified with horse radish peroxidase/organic nucleophilic-functionalized carbon nanotube composite for enhanced electrocatalytic oxidation and efficient voltammetric sensing of levodopa

    Energy Technology Data Exchange (ETDEWEB)

    Shoja, Yalda; Rafati, Amir Abbas, E-mail: aa_rafati@basu.ac.ir; Ghodsi, Javad

    2016-01-01

    A novel and selective enzymatic biosensor was designed and constructed for voltammetric determination of levodopa (L-Dopa) in aqueous media (phosphate buffer solution, pH = 7). Biosensor development was on the basis of to physically immobilizing of horse radish peroxidase (HRP) as electrochemical catalyst by sol–gel on glassy carbon electrode modified with organic nucleophilic carbon nanotube composite which in this composite p-phenylenediamine (pPDA) as organic nucleophile chemically bonded with functionalized MWCNT (MWCNT-COOH). The results of this study suggest that prepared bioorganic nucleophilic carbon nanotube composite (HRP/MWCNT-pPDA) shows fast electron transfer rate for electro oxidation of L-Dopa because of its high electrochemical catalytic activity toward the oxidation of L-Dopa, more −NH{sub 2} reactive sites and large effective surface area. Also in this work we measured L-Dopa in the presence of folic acid and uric acid as interferences. The proposed biosensor was characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), FT-IR spectroscopy and cyclic voltammetry (CV). The differential pulse voltammetry (DPV) was used for determination of L-Dopa from 0.1 μM to 1.9 μM with a low detection limit of 40 nM (for S/N = 3) and sensitivity was about 35.5 μA/μM. Also this biosensor has several advantages such as rapid response, high stability and reproducibility. - Highlights: • Glassy carbon electrode modified by a novel composite in which pPDA as nucleophile is chemically attached to MWCNTs. • The developed biosensor exhibited excellent electrocatalytic activity in electrochemically determination of L-Dopa. • The biosensor showed acceptable sensitivity, reproducibility, detection limit, selectivity and stability. • MWCNT-pPDA provides a good electrical conductivity and large effective surface area for enzyme immobilization.

  4. A Force-Sensing System on Legs for Biomimetic Hexapod Robots Interacting with Unstructured Terrain.

    Science.gov (United States)

    Zhang, He; Wu, Rui; Li, Changle; Zang, Xizhe; Zhang, Xuehe; Jin, Hongzhe; Zhao, Jie

    2017-06-27

    The tiger beetle can maintain its stability by controlling the interaction force between its legs and an unstructured terrain while it runs. The biomimetic hexapod robot mimics a tiger beetle, and a comprehensive force sensing system combined with certain algorithms can provide force information that can help the robot understand the unstructured terrain that it interacts with. This study introduces a complicated leg force sensing system for a hexapod robot that is the same for all six legs. First, the layout and configuration of sensing system are designed according to the structure and sizes of legs. Second, the joint toque sensors, 3-DOF foot-end force sensor and force information processing module are designed, and the force sensor performance parameters are tested by simulations and experiments. Moreover, a force sensing system is implemented within the robot control architecture. Finally, the experimental evaluation of the leg force sensor system on the hexapod robot is discussed and the performance of the leg force sensor system is verified.

  5. [Is the immune system our sixth sense? Relation between the immune and neuroendocrine systems].

    Science.gov (United States)

    Ferencík, M; Stvrtinová, V

    1997-04-01

    There is an overwhelming evidence that cytokines, peptide hormones and neurotransmitters, as well as their receptors, are present in the brain, endocrine and immune systems. The structure and pattern of synthesis of these peptides by leukocytes appear similar to those synthesized in the neuroendocrine system, although some differences exist. Once secreted, these peptide hormones may function as endogenous regulators inside of the each system and also in bidirectional communication between the immune and neuroendocrine systems. Such communication suggest an immunoregulatory role for the brain and a sensory function for the immune system which may sense stimuli that are not recognized by the central and peripheral nervous systems (noncognitive stimuli). The plasma hormone concentrations contributed by lymphocytes usually do not reach the levels required when the pituitary gland is the source, but because immune cells are mobile, they have the potential to deposit the hormone locally at the target site. Several immunoregulatory cytokines, including IL-1, IL-2, IL-6, IFN-gama and TNF are produced not only in the immune system but in the neuroendocrine system as well. They have profound effects on neuroendocrine functions especially on hypothalamic pituitary axes. Neuroendocrine influences that modulate the immune function mainly include mental and physical stress. It can reduce the resistance of organism to infectious diseases and malignancies by compromising the immune system directly or indirectly. The brain is not an immunologically privileged site and therefore may become the target of immunologic attacks resulting in neuroimmunological diseases with an autoimmune component. The impact of psychological and psychosocial factors on the immune system is studied by psychoneuroimmunology whereas neuroendocrine immunology is generally interested in the interactions between the immune and neuroendocrine systems under physiological and pathological conditions. The

  6. A self-sensing magnetorheological elastomer-based adaptive bridge bearing with a wireless data monitoring system

    Science.gov (United States)

    Behrooz, Majid; Yarra, Siddaiah; Mar, David; Pinuelas, Nathan; Muzinich, Blake; Publicover, Nelson G.; Pekcan, Gokhan; Itani, Ahmad; Gordaninejad, Faramarz

    2016-04-01

    This study presents an adaptive bridge bearing that can sense structural loads and tune its properties to mitigate structural vibrations. The bearing utilizes magnetorheological elastomer (MRE) layers which allow for an increased stiffness induced with a magnetic field. The system also features a MRE-based sensing system for sensing the structural wind and traffic load. The sensing system is capable of transmitting data wirelessly to a central logging computer for monitoring bridge performance and sending alerts in the case of a major event. The capability of the MRE-based sensing system for sensing structural loads and wireless transmission of data were investigated. The adaptive bridge bearing incorporates a closed-loop magnetic circuit that results in an enhanced magnetic field in the MRE layers. Results show the sensitivity of the MRE-based sensors and the performance of the wireless system, as well as the design and analysis of the tunable bridge bearing.

  7. Surface-Mount Rotor Motion Sensing System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A surface-mounted instrumentation system for measuring rotor blade motions on rotorcraft, for use both in flight and in wind tunnel testing, is proposed for...

  8. A Surface-Mounted Rotor State Sensing System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A surface-mounted instrumentation system for measuring rotor blade motions on rotorcraft, for use both in flight and in wind tunnel testing, is proposed for...

  9. Adaptive guidance and control for future remote sensing systems

    Science.gov (United States)

    Lowrie, J. W.; Myers, J. E.

    1980-01-01

    A unique approach to onboard processing was developed that is capable of acquiring high quality image data for users in near real time. The approach is divided into two steps: the development of an onboard cloud detection system; and the development of a landmark tracker. The results of these two developments are outlined and the requirements of an operational guidance and control system capable of providing continuous estimation of the sensor boresight position are summarized.

  10. SoK: Making Sense of Censorship Resistance Systems

    Directory of Open Access Journals (Sweden)

    Khattak Sheharbano

    2016-10-01

    Full Text Available An increasing number of countries implement Internet censorship at different scales and for a variety of reasons. Several censorship resistance systems (CRSs have emerged to help bypass such blocks. The diversity of the censor’s attack landscape has led to an arms race, leading to a dramatic speed of evolution of CRSs. The inherent complexity of CRSs and the breadth of work in this area makes it hard to contextualize the censor’s capabilities and censorship resistance strategies. To address these challenges, we conducted a comprehensive survey of CRSs-deployed tools as well as those discussed in academic literature-to systematize censorship resistance systems by their threat model and corresponding defenses. To this end, we first sketch a comprehensive attack model to set out the censor’s capabilities, coupled with discussion on the scope of censorship, and the dynamics that influence the censor’s decision. Next, we present an evaluation framework to systematize censorship resistance systems by their security, privacy, performance and deployability properties, and show how these systems map to the attack model. We do this for each of the functional phases that we identify for censorship resistance systems: communication establishment, which involves distribution and retrieval of information necessary for a client to join the censorship resistance system; and conversation, where actual exchange of information takes place. Our evaluation leads us to identify gaps in the literature, question the assumptions at play, and explore possible mitigations.

  11. Studies of Hybrid Nano-Bio-System: Single-Walled Carbon Nanotubes and Hydrogenase

    Energy Technology Data Exchange (ETDEWEB)

    Svedruzic-Chang, D.; Blackburn, J. L.; McDonald, T. J.; Heben, M. J.; King, P. W.

    2008-01-01

    We have examined changes in single-walled carbon nanotubes (SWNT) optical signals upon addition of recombinant [FeFe] hydrogenases from Clostridium acetobutylicum or Chlamydomonas reinhardtii. We found evidence that novel and stable charge-transfer complexes are formed only under conditions of hydrogenase catalytic turnover. Formation of the complex sensitizes the nanotubes to the proton-to-hydrogen redox half-reaction. Thus, the experimental potential can be altered by changing the pH or molecular hydrogen concentration. In the presence of molecular hydrogen, hydrogenase mediates electron injection into the conduction band of semiconducting SWNT, which was observed as a quenching of the photoluminescence signals. Here, we will present recent Raman studies, which revealed that SWNTs in a complex with hydrogenase may undergo either oxidation or reduction, depending on the electronic structure of the SWNT and the oxidation state of the enzyme. In addition, we will describe our efforts to prepare stable, solubilized SWNT/hydrogenase complexes in the absence of detergent. This work shows that SWNT/hydrogenase complexes have potential applications as a component of an energy conversion device.

  12. P25 nanoparticles decorated on titania nanotubes arrays as effective drug delivery system for ibuprofen

    Science.gov (United States)

    Wang, Zhang; Xie, Chunlin; Luo, Fei; Li, Ping; Xiao, Xiufeng

    2015-01-01

    In this study, uniformly distributed layer of P25 nanoparticles (NPs) decorated on titania (TiO2) nanotubes (TNTs) arrays was prepared in a teflon-lined stainless steel autoclave by the hydrothermal treatment. To investigate the influence of the P25 concentration, different concentrations of P25 NPs were added into the solution to obtain the optimal decorative effect. TNTs decorated with P25 (TNTs-P25) and TNTs without P25 decorated on its surface were loaded with ibuprofen (IBU) via vacuum drying and its release properties were investigated. The samples were characterized by field emission scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The results indicated that P25 NPs were successfully decorated on the surface of TNTs by hydrothermal method and the optimal concentration was found to be 7.5 × 10-4 M. P25 NPs decorated on TNTs led to a significant increase in the specific surface area of TNTs which was conducive to improve the loading effect of IBU. Importantly, the diameters of the decorated nanotubes were reduced to 100 ± 10 nm and the increase in roughness led to an effective and prolonged drug release.

  13. TiO2 nanotubes as animal drug delivery system and in vitro controlled release.

    Science.gov (United States)

    Lai, Shuting; Zhang, Wei; Liu, Fang; Wu, Cui; Zeng, Dongping; Sun, Yongxue; Xu, Yuehua; Fang, Yueping; Zhou, Wuyi

    2013-01-01

    The enrofloxacin hydrochloride (Enro), an anti-inflammatory drug for the animals, was loaded on the TNTs through physical absorption due to the high specific surface area and excellent surface activity of the TiO2 nanotubes. The samples were characterized by XRD, BET, TEM, TG and FTIR. The in vitro controlled release behavior at different temperatures was studied in detail. The results showed that the obtained TNTs were uniform and mainly amorphous crystal phase with a diameter of 10-15 nm and a length of 350-400 nm. By investigating the effect of the hydrothermal reaction process of the obtained TiO2 nanotubes and the drug loading frequency on the loading content of Enro drugs, the results indicated that the increasing loading frequency of the drug was available for the drug loading and the maximum loading content of drug reached to 33.28%. Enro-TNTs performed a better release profile at low temperature than at high temperature in PBS solution. The Higuchi square root models are suitable to explain the in vitro drug release behavior of Enro from Enro-TNTs.

  14. Sustained Release and Cytotoxicity Evaluation of Carbon Nanotube-Mediated Drug Delivery System for Betulinic Acid

    Directory of Open Access Journals (Sweden)

    Julia M. Tan

    2014-01-01

    Full Text Available Carbon nanotubes (CNTs have been widely utilized as a novel drug carrier with promising future applications in biomedical therapies due to their distinct characteristics. In the present work, carboxylic acid-functionalized single-walled carbon nanotubes (f-SWCNTs were used as the starting material to react with anticancer drug, BA to produce f-SWCNTs-BA conjugate via π-π stacking interaction. The conjugate was extensively characterized for drug loading capacity, physicochemical properties, surface morphology, drug releasing characteristics, and cytotoxicity evaluation. The results indicated that the drug loading capacity was determined to be around 20 wt% and this value has been verified by thermogravimetric analysis. The binding of BA onto the surface of f-SWCNTs was confirmed by FTIR and Raman spectroscopies. Powder XRD analysis showed that the structure of the conjugate was unaffected by the loading of BA. The developed conjugate was found to release the drug in a controlled manner with a prolonged release property. According to the preliminary in vitro cytotoxicity studies, the conjugate was not toxic in a standard fibroblast cell line, and anticancer activity was significantly higher in A549 than HepG2 cell line. This study suggests that f-SWCNTs could be developed as an efficient drug carrier to conjugate drugs for pharmaceutical applications in cancer chemotherapies.

  15. Probing lithium germanide phase evolution and structural change in a germanium-in-carbon nanotube energy storage system.

    Science.gov (United States)

    Tang, Wei; Liu, Yanpeng; Peng, Chengxin; Hu, Mary Y; Deng, Xuchu; Lin, Ming; Hu, Jian Zhi; Loh, Kian Ping

    2015-02-25

    Lithium alloys of group IV elements such as silicon and germanium are attractive candidates for use as anodes in high-energy-density lithium-ion batteries. However, the poor capacity retention arising from volume swing during lithium cycling restricts their widespread application. Herein, we report high reversible capacity and superior rate capability from core-shell structure consisting of germanium nanorods embedded in multiwall carbon nanotubes. To understand how the core-shell structure helps to mitigate volume swings and buffer against mechanical instability, transmission electron microscopy, X-ray diffraction, and in situ (7)Li nuclear magnetic resonance were used to probe the structural rearrangements and phase evolution of various Li-Ge alloy phases during (de)alloying reactions with lithium. The results provide insights into amorphous-to-crystalline transition and lithium germanide alloy phase transformation, which are important reactions controlling performance in this system.

  16. Practical Approach To Building A Mid-Wave Remote Sensing System

    Energy Technology Data Exchange (ETDEWEB)

    Pyke, Benjamin J. [Univ. of Arizona, Tucson, AZ (United States)

    2017-01-01

    The purpose of this project, Laser Active Transmitter & Receiver (LATR), was to build a mobile ground based remote sensing system that can detect, identify and quantify a specific gaseous species using Differential Absorption LIDAR (DIAL). This thesis project is concerned with the development and field testing of a mid-wave infrared active remote sensing system, capable of identifying and quantifying emissions in the 3.2 – 3.5 micron range. The goal is to give a brief description of what remote sensing is about and the specific technique used to analyze the collected data. The thesis will discuss the transmitter and the associated subsystems used to create the required wavelength, and the receiver used to collect the returns. And finally, the thesis will discuss the process of collecting the data and some of the results from field and lab collections.

  17. Famine Early Warning Systems and Their Use of Satellite Remote Sensing Data

    Science.gov (United States)

    Brown, Molly E.; Essam, Timothy; Leonard, Kenneth

    2011-01-01

    Famine early warning organizations have experience that has much to contribute to efforts to incorporate climate and weather information into economic and political systems. Food security crises are now caused almost exclusively by problems of food access, not absolute food availability, but the role of monitoring agricultural production both locally and globally remains central. The price of food important to the understanding of food security in any region, but it needs to be understood in the context of local production. Thus remote sensing is still at the center of much food security analysis, along with an examination of markets, trade and economic policies during food security analyses. Technology including satellite remote sensing, earth science models, databases of food production and yield, and modem telecommunication systems contributed to improved food production information. Here we present an econometric approach focused on bringing together satellite remote sensing and market analysis into food security assessment in the context of early warning.

  18. Versatile computer-controlled system for characterization of gas sensing materials.

    Science.gov (United States)

    Zhao, M; Huang, J X; Wong, M H; Tang, Y M; Ong, C W

    2011-10-01

    Design of a system used for characterizing gas sensing materials is described. It is distinctive of being able to measure electrical and optical responses of a sample simultaneously, control a number of measurement parameters, perform fast exchange of gaseous environment, and be fully controlled automatically. These features make the system to be versatile in determining most concerned performance indexes of a gas sensing material (e.g., sensitivity, stability, selectivity, response/recovery times, etc.) as functions of various combinations of measurement conditions (e.g., gas concentrations, temperature, total pressure, content of interferants, photo assist, relative humidity, soaking time in a fixed gas concentration, and number of switching cycles in a dynamic test, etc.). Rationales of the designs associated with general gas sensing mechanics are discussed.

  19. Can Remote Sensing Detect Aquifer Characteristics?: A Case Study in the Guarani Aquifer System

    Science.gov (United States)

    Richey, A. S.; Thomas, B.; Famiglietti, J. S.

    2013-12-01

    Global water supply resiliency depends on groundwater, especially regions threatened by population growth and climate change. Aquifer characteristics, even as basic as confined versus unconfined, are necessary to prescribe regulations to sustainably manage groundwater supplies. A significant barrier to sustainable groundwater management exists in the difficulties associated with mapping groundwater resources and characteristics at a large spatial scale. This study addresses this challenge by investigating if remote sensing, including with NASA's Gravity Recovery and Climate Experiment (GRACE), can detect and quantify key aquifer parameters and characteristics. We explore this through a case study in the Guarani Aquifer System (GAS) of South America, validating our remote sensing-based findings against the best available regional estimates. The use of remote sensing to advance the understanding of large aquifers is beneficial to sustainable groundwater management, especially in a trans-boundary system, where consistent information exchange can occur within hydrologic boundaries instead of political boundaries.

  20. Design and Implementation of a High Spatial Resolution Remote Sensing Image Intelligent Interpretation System

    Directory of Open Access Journals (Sweden)

    Deng-Kui Mo

    2007-08-01

    Full Text Available Very high spatial resolution remote sensing images have applications in many fields. However, research on the intelligent interpretation of such images is insufficient partly because of their the complexity and large size. In this study, a high spatial resolution remote sensing image intelligent interpretation system (HSR-RSIIIs was designed with image segmentation, a geographical information system, and a data-mining algorithm. Some key methods such as image segmentation, feature extraction, feature selection, and classification algorithm for interpreting high spatial resolution remote sensing image have been studied. A land cover classification experiment was performed in the Zhuzhou area using a Quickbird multi-spectral image. The classification results were consistent with the visual interpretation results. In additional, the proposed interpretation method was compared with the traditional pixel-based method. The results indicate that the method proposed in the literature is more effective and intelligent than that used previously.