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Sample records for membrane sensor based

  1. Stress-sensor device based on flexoelectric liquid crystalline membranes.

    Science.gov (United States)

    Rey, Alejandro D; Servio, Phillip; Herrera Valencia, Edtson Emilio

    2014-05-19

    Membrane flexoelectricity is an electromechanical coupling process that describes membrane bending and membrane electrical polarization caused by bending under electric fields. In this paper we propose, formulate, and characterize a stress-sensor device for mechanically loaded solids, consisting of a soft flexoelectric thin membrane attached to the loaded deformed solid. Because the curvature of the deformed solid is transferred to the attached flexoelectric membrane, the electromechanical transduction of the latter produces a charge that is proportional to the stress of the solid. The model of the stress-sensor device is based on the integration of the thermodynamics of polarizable membranes with isotropic solid elasticity, leading to a transfer function that identifies the elastic, electromechanical, and geometrical parameters involved in electrical-signal generation. The model is applied to representative normal bending and then to more complex off-axis bending of elastic bars. In all cases, a common transfer function shows the generic material and its geometric contributions. The sensor sensitivity increases linearly with flexoelectricity and the membrane-solid interface, and the sensitivity decreases with increasing membrane thickness and Young's modulus of the solid. The theoretical results contribute to ongoing experimental efforts towards the development of anisotropic soft-matter-based stress-sensor devices through solid-membrane interactions and electromechanical transduction. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Bio-Mimetic Sensors Based on Molecularly Imprinted Membranes

    Directory of Open Access Journals (Sweden)

    Catia Algieri

    2014-07-01

    Full Text Available An important challenge for scientific research is the production of artificial systems able to mimic the recognition mechanisms occurring at the molecular level in living systems. A valid contribution in this direction resulted from the development of molecular imprinting. By means of this technology, selective molecular recognition sites are introduced in a polymer, thus conferring it bio-mimetic properties. The potential applications of these systems include affinity separations, medical diagnostics, drug delivery, catalysis, etc. Recently, bio-sensing systems using molecularly imprinted membranes, a special form of imprinted polymers, have received the attention of scientists in various fields. In these systems imprinted membranes are used as bio-mimetic recognition elements which are integrated with a transducer component. The direct and rapid determination of an interaction between the recognition element and the target analyte (template was an encouraging factor for the development of such systems as alternatives to traditional bio-assay methods. Due to their high stability, sensitivity and specificity, bio-mimetic sensors-based membranes are used for environmental, food, and clinical uses. This review deals with the development of molecularly imprinted polymers and their different preparation methods. Referring to the last decades, the application of these membranes as bio-mimetic sensor devices will be also reported.

  3. Bio-Mimetic Sensors Based on Molecularly Imprinted Membranes

    Science.gov (United States)

    Algieri, Catia; Drioli, Enrico; Guzzo, Laura; Donato, Laura

    2014-01-01

    An important challenge for scientific research is the production of artificial systems able to mimic the recognition mechanisms occurring at the molecular level in living systems. A valid contribution in this direction resulted from the development of molecular imprinting. By means of this technology, selective molecular recognition sites are introduced in a polymer, thus conferring it bio-mimetic properties. The potential applications of these systems include affinity separations, medical diagnostics, drug delivery, catalysis, etc. Recently, bio-sensing systems using molecularly imprinted membranes, a special form of imprinted polymers, have received the attention of scientists in various fields. In these systems imprinted membranes are used as bio-mimetic recognition elements which are integrated with a transducer component. The direct and rapid determination of an interaction between the recognition element and the target analyte (template) was an encouraging factor for the development of such systems as alternatives to traditional bio-assay methods. Due to their high stability, sensitivity and specificity, bio-mimetic sensors-based membranes are used for environmental, food, and clinical uses. This review deals with the development of molecularly imprinted polymers and their different preparation methods. Referring to the last decades, the application of these membranes as bio-mimetic sensor devices will be also reported. PMID:25196110

  4. PVC-MEMBRANE POTENTIOMETRIC SENSORS BASED ON A ...

    African Journals Online (AJOL)

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    ethylimino)-1,3-dihydro-indol-. 2-one (DEDIO) as an ionophore in poly(vinyl chloride) (PVC) matrix, is reported. The plasticized membrane sensor exhibits a Nernstian response for Fe(III) ions over a wide concentration range (2.0 × 10-6 - 5.0 ...

  5. Novel membrane-based electrochemical sensor for real-time bio-applications

    DEFF Research Database (Denmark)

    Al Atraktchi, Fatima Al-Zahraa; Bakmand, Tanya; Dimaki, Maria

    2014-01-01

    experiments showed that the membrane-sensor was suitable as a cell culturing substrate for bio-applications. Real-time measurements of dopamine exocytosis in cell cultures were performed, where the transmitter release was recorded at the point of release. The developed membrane-sensor provides a new......This article presents a novel membrane-based sensor for real-time electrochemical investigations of cellular- or tissue cultures. The membrane sensor enables recording of electrical signals from a cell culture without any signal dilution, thus avoiding loss of sensitivity. Moreover, the porosity...

  6. Samarium (III Selective Membrane Sensor Based on Tin (IV Boratophosphate

    Directory of Open Access Journals (Sweden)

    Ashok S. K. Kumar

    2004-08-01

    Full Text Available Abstract: A number of Sm (III selective membranes of varying compositions using tin (IV boratophosphate as electroactive material were prepared. Polyvinyl chloride, polystyrene and epoxy resin were used as binding materials. Membrane having composition of 40% exchanger and 60% epoxy resin exhibited best performance. This membrane worked well over a wide concentration range of 1x10-5M to 1x10-1 M of samarium ions with a Super-Nernstian slope of 40 mV/decade. It has a fast response time of less than 10 seconds and can be used for at least six months without any considerable divergence in potentials. The proposed sensor revealed good selectivities with respect to alkali, alkaline earth, some transition and rare earth metal ions and can be used in the pH range of 4.0-10.0. It was used as an indicator electrode in the potentiometric titration of Sm (III ions against EDTA. Effect of internal solution was studied and the electrode was successfully used in non-aqueous media, too.

  7. Novel Membrane-Based Electrochemical Sensor for Real-Time Bio-Applications

    Directory of Open Access Journals (Sweden)

    Fatima AlZahra'a Alatraktchi

    2014-11-01

    Full Text Available This article presents a novel membrane-based sensor for real-time electrochemical investigations of cellular- or tissue cultures. The membrane sensor enables recording of electrical signals from a cell culture without any signal dilution, thus avoiding loss of sensitivity. Moreover, the porosity of the membrane provides optimal culturing conditions similar to existing culturing techniques allowing more efficient nutrient uptake and molecule release. The patterned sensor electrodes were fabricated on a porous membrane by electron-beam evaporation. The electrochemical performance of the membrane electrodes was characterized by cyclic voltammetry and chronoamperometry, and the detection of synthetic dopamine was demonstrated down to a concentration of 3.1 pM. Furthermore, to present the membrane-sensor functionality the dopamine release from cultured PC12 cells was successfully measured. The PC12 cells culturing experiments showed that the membrane-sensor was suitable as a cell culturing substrate for bio-applications. Real-time measurements of dopamine exocytosis in cell cultures were performed, where the transmitter release was recorded at the point of release. The developed membrane-sensor provides a new functionality to the standard culturing methods, enabling sensitive continuous in vitro monitoring and closely mimicking the in vivo conditions.

  8. Membrane-Based Characterization of a Gas Component — A Transient Sensor Theory

    Directory of Open Access Journals (Sweden)

    Detlef Lazik

    2014-03-01

    Full Text Available Based on a multi-gas solution-diffusion problem for a dense symmetrical membrane this paper presents a transient theory of a planar, membrane-based sensor cell for measuring gas from both initial conditions: dynamic and thermodynamic equilibrium. Using this theory, the ranges for which previously developed, simpler approaches are valid will be discussed; these approaches are of vital interest for membrane-based gas sensor applications. Finally, a new theoretical approach is introduced to identify varying gas components by arranging sensor cell pairs resulting in a concentration independent gas-specific critical time. Literature data for the N2, O2, Ar, CH4, CO2, H2 and C4H10 diffusion coefficients and solubilities for a polydimethylsiloxane membrane were used to simulate gas specific sensor responses. The results demonstrate the influence of (i the operational mode; (ii sensor geometry and (iii gas matrices (air, Ar on that critical time. Based on the developed theory the case-specific suitable membrane materials can be determined and both operation and design options for these sensors can be optimized for individual applications. The results of mixing experiments for different gases (O2, CO2 in a gas matrix of air confirmed the theoretical predictions.

  9. Novel flexible chemical gas sensor based on poly(3,4-ethylenedioxythiophene) nanotube membrane.

    Science.gov (United States)

    Kwon, Oh Seok; Park, Eunyu; Kweon, O Young; Park, Seon Joo; Jang, Jyongsik

    2010-09-15

    Poly(3,4-ethylenedioxythiophene) nanotubes (PEDOT NTs) flexible membrane was successfully fabricated by vapor deposition polymerization (VDP) mediated electrospinning for ammonia gas detection. PVA nanofibers (NFs) were electrospun as a core part and polyvinyl alcohol (PVA)/PEDOT coaxial nanocables (NCs) were prepared by VDP method via EDOT monomer adsorption onto the electrospun PVA NFs as templates. To obtain the PEDOT NTs membrane, the PVA NFs were removed from PVA/PEDOT coaxial NCs with distilled water. PVA/PEDOT coaxial NCs and PEDOT NTs had the conductivities of 71 and 61 Scm(-1) and were applied as a transducer for ammonia gas detection in the range of 1-100 parts per million (ppm) of NH(3) gas. They exhibited the minimum detectable level of ca. 5 parts per million (ppm) and fast response time (less than 1s) towards ammonia gas. In a recovery time, the PEDOT NTs membrane sensor was ca. 30s and shorter compared to that of the membrane sensor based on the PVA/PEDOT NCs (ca. 50s). In addition, sensor performance of PEDOT NTs membrane was also undertaken as a function of membrane thickness. Thick membrane sensor (30 microm) had the enhanced sensitivity and the sensitivity on the membrane thickness was in the order of 30 microm>20 microm>10 microm at 60 ppm of NH(3) gas. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  10. Crosslinked basement membrane-based coatings enhance glucose sensor function and continuous glucose monitoring in vivo.

    Science.gov (United States)

    Klueh, Ulrike; Ludzinska, Izabela; Czajkowski, Caroline; Qiao, Yi; Kreutzer, Donald L

    2018-01-01

    Overcoming sensor-induced tissue reactions is an essential element of achieving successful continuous glucose monitoring (CGM) in the management of diabetes, particularly when used in closed loop technology. Recently, we demonstrated that basement membrane (BM)-based glucose sensor coatings significantly reduced tissue reactions at sites of device implantation. However, the biocompatible BM-based biohydrogel sensor coating rapidly degraded over a less than a 3-week period, which effectively eliminated the protective sensor coating. In an effort to increase the stability and effectiveness of the BM coating, we evaluated the impact of crosslinking BM utilizing glutaraldehyde as a crosslinking agent, designated as X-Cultrex. Sensor performance (nonrecalibrated) was evaluated for the impact of these X-Cultrex coatings in vitro and in vivo. Sensor performance was assessed over a 28-day time period in a murine CGM model and expressed as mean absolute relative difference (MARD) values. Tissue reactivity of Cultrex-coated, X-Cultrex-coated, and uncoated glucose sensors was evaluated over a 28-day time period in vivo using standard histological techniques. These studies demonstrated that X-Cultrex-based sensor coatings had no effect on glucose sensor function in vitro. In vivo, glucose sensor performance was significantly enhanced following X-Cultrex coating throughout the 28-day study. Histological evaluations of X-Cultrex-treated sensors demonstrated significantly less tissue reactivity when compared to uncoated sensors. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 7-16, 2018. © 2017 Wiley Periodicals, Inc.

  11. Approach for Self-Calibrating CO2 Measurements with Linear Membrane-Based Gas Sensors

    Directory of Open Access Journals (Sweden)

    Detlef Lazik

    2016-11-01

    Full Text Available Linear membrane-based gas sensors that can be advantageously applied for the measurement of a single gas component in large heterogeneous systems, e.g., for representative determination of CO2 in the subsurface, can be designed depending on the properties of the observation object. A resulting disadvantage is that the permeation-based sensor response depends on operating conditions, the individual site-adapted sensor geometry, the membrane material, and the target gas component. Therefore, calibration is needed, especially of the slope, which could change over several orders of magnitude. A calibration-free approach based on an internal gas standard is developed to overcome the multi-criterial slope dependency. This results in a normalization of sensor response and enables the sensor to assess the significance of measurement. The approach was proofed on the example of CO2 analysis in dry air with tubular PDMS membranes for various CO2 concentrations of an internal standard. Negligible temperature dependency was found within an 18 K range. The transformation behavior of the measurement signal and the influence of concentration variations of the internal standard on the measurement signal were shown. Offsets that were adjusted based on the stated theory for the given measurement conditions and material data from the literature were in agreement with the experimentally determined offsets. A measurement comparison with an NDIR reference sensor shows an unexpectedly low bias (<1% of the non-calibrated sensor response, and comparable statistical uncertainty.

  12. Approach for Self-Calibrating CO₂ Measurements with Linear Membrane-Based Gas Sensors.

    Science.gov (United States)

    Lazik, Detlef; Sood, Pramit

    2016-11-17

    Linear membrane-based gas sensors that can be advantageously applied for the measurement of a single gas component in large heterogeneous systems, e.g., for representative determination of CO₂ in the subsurface, can be designed depending on the properties of the observation object. A resulting disadvantage is that the permeation-based sensor response depends on operating conditions, the individual site-adapted sensor geometry, the membrane material, and the target gas component. Therefore, calibration is needed, especially of the slope, which could change over several orders of magnitude. A calibration-free approach based on an internal gas standard is developed to overcome the multi-criterial slope dependency. This results in a normalization of sensor response and enables the sensor to assess the significance of measurement. The approach was proofed on the example of CO₂ analysis in dry air with tubular PDMS membranes for various CO₂ concentrations of an internal standard. Negligible temperature dependency was found within an 18 K range. The transformation behavior of the measurement signal and the influence of concentration variations of the internal standard on the measurement signal were shown. Offsets that were adjusted based on the stated theory for the given measurement conditions and material data from the literature were in agreement with the experimentally determined offsets. A measurement comparison with an NDIR reference sensor shows an unexpectedly low bias (sensor response, and comparable statistical uncertainty.

  13. Schiff's Bases and Crown Ethers as Supramolecular Sensing Materials in the Construction of Potentiometric Membrane Sensors

    Directory of Open Access Journals (Sweden)

    Siavash Riahi

    2008-03-01

    Full Text Available Ionophore incorporated PVC membrane sensors are well-established analyticaltools routinely used for the selective and direct measurement of a wide variety of differentions in complex biological and environmental samples. Potentiometric sensors have someoutstanding advantages including simple design and operation, wide linear dynamic range,relatively fast response and rational selectivity. The vital component of such plasticizedPVC members is the ionophore involved, defining the selectivity of the electrodes' complexformation. Molecular recognition causes the formation of many different supramolecules.Different types of supramolecules, like calixarenes, cyclodextrins and podands, have beenused as a sensing material in the construction of ion selective sensors. Schiff's bases andcrown ethers, which feature prominently in supramolecular chemistry, can be used assensing materials in the construction of potentiometric ion selective electrodes. Up to now,more than 200 potentiometric membrane sensors for cations and anions based on Schiff'sbases and crown ethers have been reported. In this review cation binding and anioncomplexes will be described. Liquid membrane sensors based on Schiff's bases and crownethers will then be discussed.

  14. PVC-membrane potentiometric sensors based on a recently ...

    African Journals Online (AJOL)

    It has a fast response time of <12 s and can be used for ten weeks without any considerable divergences in its potentials .the electrode can be used in the pH range 4.5-8.0. The proposed sensor shows fairly good discriminating ability towards Fe(III) ion in comparison with a large number of alkali, alkaline earth, transition ...

  15. Fiber Temperature Sensor Based on Micro-mechanical Membranes and Optical Interference Structure

    International Nuclear Information System (INIS)

    Liu Yueming; Tian Weijian; Hua Jing

    2011-01-01

    A novel fiber temperature sensor is presented theoretically and experimentally in this paper. Its working principle is based on Optical Fabry-Perot interference structure that is formed between a polished optical fiber end and micro-mechanical Bi-layered membranes. When ambient temperature is varying, Bi-layered membranes will be deflected and the length of Fabry-Perot cavity will be changed correspondingly. By detecting the reflecting optical intensity from the Fabry-Perot cavity, the ambient temperature can be measured. Using finite element software ANSYS, the sensor structure was optimized based on optical Interference theory and Bi-layered membranes thermal expansion theory, and theoretical characteristics was simulated by computer software. In the end, using optical fiber 2x2 coupler and photo-electrical detector, the fabricated sample sensor was tested successfully by experiment that demonstrating above theoretical analysis and simulation results. This sensor has some favorable features, such as: micro size owing to its micro-mechanical structure, high sensitivity owing to its working Fabry-Perot interference cavity structure, and optical integration character by using optical fiber techniques.

  16. Design of air blast pressure sensors based on miniature silicon membrane and piezoresistive gauges

    Science.gov (United States)

    Riondet, J.; Coustou, A.; Aubert, H.; Pons, P.; Lavayssière, M.; Luc, J.; Lefrançois, A.

    2017-11-01

    Available commercial piezoelectric pressure sensors are not able to accurately reproduce the ultra-fast transient pressure occurring during an air blast experiment. In this communication a new pressure sensor prototype based on a miniature silicon membrane and piezoresistive gauges is reported for significantly improving the performances in terms of time response. Simulation results demonstrate the feasibility of a pressure transducer having a fundamental resonant frequency almost ten times greater than the commercial piezoelectric sensors one. The sensor uses a 5μm-thick SOI membrane and four P-type silicon gauges (doping level ≅ 1019 at/cm3) in Wheatstone bridge configuration. To obtain a good trade-off between the fundamental mechanical resonant frequency and pressure sensitivity values, the typical dimension of the rectangular membrane is fixed to 30μm x 90μm with gauge dimension of 1μm x 5μm. The achieved simulated mechanical resonant frequency of these configuration is greater than 40MHz with a sensitivity of 0.04% per bar.

  17. Catalytic Membrane Sensors

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-12-01

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

  18. A Capacitive Humidity Sensor Based on an Electrospun PVDF/Graphene Membrane

    Directory of Open Access Journals (Sweden)

    Daniel Hernández-Rivera

    2017-05-01

    Full Text Available Humidity sensors have been widely used in areas such as agriculture, environmental conservation, medicine, instrumentation and climatology. Hydrophobicity is one of the important factors in capacitive humidity sensors: recent research has shown that the inclusion of graphene (G in polyvinylidene fluoride (PVDF improves its hydrophobicity. In this context, a methodology to fabricate electrospun membranes of PVDF blended with G was developed in order to improve the PVDF properties allowing the use of PVDF/G membrane as a capacitive humidity sensor. Micrographs of membranes were obtained by scanning electron microscopy to analyze the morphology of the fabricated samples. Subsequently, the capacitive response of the membrane, which showed an almost linear and directly proportional response to humidity, was tested. Results showed that the response time of PVDF/G membrane was faster than that of a commercial DHT11 sensor. In summary, PVDF/G membranes exhibit interesting properties as humidity sensors.

  19. Gliclazide as novel carrier in construction of PVC-based La(III)-selective membrane sensor.

    Science.gov (United States)

    Ganjali, Mohammad Reza; Daftari, Azadeh; Rezapour, Morteza; Puorsaberi, Tahereh; Haghgoo, Soheila

    2003-03-01

    A PVC-based sensor for La(3+) ions based on N-[hexahydrocyclopentapyrol-2((1H)yl)amino]carbonyl]-4-methyl benzene sulfonamide (gliclazide) as a novel carrier was prepared. The electrode exhibits a Nernstian response for La(3+) over a wide concentration range (1.0x10(-1)-1.0x10(-6) M) with a slope of 20.1 mV per decade. The limit of detection is 8.0x10(-7) M. The sensor has a very short response time (<15 s) and a useful working pH range of 4.0-8.0. The proposed membrane sensor shows excellent discriminating ability towards La(3+) ions with regard to several alkali, alkaline earth, transition and heavy metal ions. The electrode was successfully applied for determination of La(3+) in binary mixtures.

  20. New sensor based on membranes with magnetic nano-inclusions for early diagnosis in periodontal disease.

    Science.gov (United States)

    Totu, Eugenia Eftimie; Isildak, Ibrahim; Nechifor, Aurelia Cristina; Cristache, Corina Marilena; Enachescu, Marius

    2018-04-15

    A series of sodium selective membranes with magnetic nano-inclusions using p-tertbutyl calix[4]arene as ionophore and polymeric matrix (polyvinyl chloride) have been developed, and the corresponding sodium selective sensors were obtained for the first time. A linear range was registered between 3.1 × 10 -5 and 10 -1 moldm -3 and near Nernstian electrochemical answer: 55.73mV/decade has been recoreded for PVC (polyvinyl chloride) - based sodium selective sensor, with a response time of 45s. Due to their small dimensions, sensors could be used for measuring ions from the gingival crevicular fluid directly into the peri-odontal pocket, avoiding the difficulties of collecting an appropriate amount of fluid for analysis. Alterations in the inorganic ions level could be evidenced with this new device, assisting the early diagnosis and prevention of periodontal disease. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Highly selective and sensitive monohydrogen phosphate membrane sensor based on molybdenum acetylacetonate

    International Nuclear Information System (INIS)

    Ganjali, Mohammad Reza; Norouzi, Parviz; Ghomi, Mahnaz; Salavati-Niasari, Masoud

    2006-01-01

    In this work, a highly selective and sensitive monohydrogen phosphate membrane sensor based on a molybdenum bis(2-hydroxyanil) acetylacetonate complex (MAA) is reported. The sensor shows a linear dynamic range between 1.0 x 10 -1 and 1.0 x 10 -7 M, with a nice Nernstian behavior (-29.5 ± 0.3 mV decade -1 ) in pH of 8.2. The detection limit of the electrode is 6.0 x 10 -8 M (∼6 ppb). The best performance was obtained with a membrane composition of 32% poly(vinyl chloride), 58% benzyl acetate, 2% hexadecyltrimethylammonium bromide and 8% MAA. The sensor possesses the advantages of short response time, low detection limit and especially, very good selectivity towards a large number of organic and inorganic anions including salicylate, citrate, tartarate, acetate, oxalate, fluoride, chloride, bromide, iodide, sulfite, sulfate, nitrate, nitrite, cyanide, thiocyanate, perchlorate, metavanadate, and bicarbonate ions. The electrode can be used for at least 10 weeks without any considerable divergence in its slope and detection limit. It was used as an indicator electrode in potentiometric titration of monohydrogenphosphate ion with barium chloride. The proposed sensor was successfully applied to direct determination of monohydrogenphosphate in two fertilizer samples (NPK)

  2. Polymeric membrane sensors based on Cd(II) Schiff base complexes for selective iodide determination in environmental and medicinal samples.

    Science.gov (United States)

    Singh, Ashok Kumar; Mehtab, Sameena

    2008-01-15

    The two cadmium chelates of schiff bases, N,N'-bis(salicylidene)-1,4-diaminobutane, (Cd-S(1)) and N,N'-bis(salicylidene)-3,4-diaminotoluene (Cd-S(2)), have been synthesized and explored as ionophores for preparing PVC-based membrane sensors selective to iodide(I) ion. Potentiometric investigations indicate high affinity of these receptors for iodide ion. Polyvinyl chloride (PVC)-based membranes of Cd-S(1) and Cd-S(2) using as hexadecyltrimethylammonium bromide (HTAB) cation discriminator and o-nitrophenyloctyl ether (o-NPOE), dibutylphthalate (DBP), acetophenone (AP) and tributylphosphate (TBP) as plasticizing solvent mediators were prepared and investigated as iodide-selective sensors. The best performance was shown by the membrane of composition (w/w) of (Cd-S(1)) (7%):PVC (31%):DBP (60%):HTAB (2%). The sensor works well over a wide concentration range 5.3x10(-7) to 1.0x10(-2)M with Nernstian compliance (59.2mVdecade(-1) of activity) within pH range 2.5-9.0 with a response time of 11s and showed good selectivity for iodide ion over a number of anions. The sensor exhibits adequate life (3 months) with good reproducibility (S.D.+/-0.24mV) and could be used successfully for the determination of iodide content in environmental water samples and mouth wash samples.

  3. Highly sensitive oxygen sensors based on Cu(I) complex-polystyrene composite nanofibrous membranes prepared by electrospinning.

    Science.gov (United States)

    Wang, Yinghui; Li, Bin; Liu, Yanhong; Zhang, Liming; Zuo, Qinghui; Shi, Linfang; Su, Zhongmin

    2009-10-21

    The first optical oxygen sensor based on Cu(I) complex-polystyrene composite nanofibrous membranes, showing high sensitivity (I(0)/I(100) = 15.56), good linear Stern-Volmer characteristics (R(2) = 0.9966) and short response/recovery time (t(decrease) (s) = 7 and t(increase) (s) = 14), has been prepared; these results represent the best values reported for oxygen sensors based on Cu(I) complexes.

  4. Ionophore-based potentiometric PVC membrane sensors for determination of phenobarbitone in pharmaceutical formulations

    Directory of Open Access Journals (Sweden)

    Alrabiah Haitham

    2016-12-01

    Full Text Available The fabrication and development of two polyvinyl chloride (PVC membrane sensors for assaying phenobarbitone sodium are described. Sensors 1 and 2 were fabricated utilizing β- or γ-cyclodextrin as ionophore in the presence of tridodecylmethylammonium chloride as a membrane additive, and PVC and dioctyl phthalate as plasticizer. The analytical parameters of both sensors were evaluated according to the IUPAC guidelines. The proposed sensors showed rapid, stable anionic response (-59.1 and -62.0 mV per decade over a relatively wide phenobarbitone concentration range (5.0 × 10-6-1 × 10-2 and 8 × 10-6-1 × 10-2 mol L-1 in the pH range of 9-11. The limit of detection was 3.5 × 10-6 and 7.0 × 10-6 mol L-1 for sensors 1 and 2, respectively. The fabricated sensors showed high selectivity for phenobarbitone over the investigated foreign species. An average recovery of 2.54 μg mL-1 phenobarbitone sodium was 97.4 and 101.1 %, while the mean relative standard deviation was 3.0 and 2.1 %, for sensors 1 and 2, respectively. The results acquired for determination of phenobarbitone in its dosage forms utilizing the proposed sensors are in good agreement with those obtained by the British Pharmacopoeial method.

  5. A Flexible Optical pH Sensor Based on Polysulfone Membranes Coated with pH-Responsive Polyaniline Nanofibers

    Directory of Open Access Journals (Sweden)

    Nedal Abu-Thabit

    2016-06-01

    Full Text Available A new optical pH sensor based on polysulfone (PSU and polyaniline (PANI was developed. A transparent and flexible PSU membrane was employed as a support. The electrically conductive and pH-responsive PANI was deposited onto the membrane surface by in situ chemical oxidative polymerization (COP. The absorption spectra of the PANI-coated PSU membranes exhibited sensitivity to pH changes in the range of 4–12, which allowed for designing a dual wavelength pH optical sensor. The performance of the membranes was assessed by measuring their response starting from high pH and going down to low pH, and vice versa. It was found that it is necessary to precondition the sensor layers before each measurement due to the slight hysteresis observed during forward and backward pH titrations. PSU membranes with polyaniline coating thicknesses in the range of ≈100–200 nm exhibited fast response times of <4 s, which are attributed to the porous, rough and nanofibrillar morphology of the polyaniline coating. The fabricated pH sensor was characterized by a sigmoidal response (R2 = 0.997 which allows for pH determination over a wide dynamic range. All membranes were stable for a period of more than six months when stored in 1 M HCl solution. The reproducibility of the fabricated optical pH sensors was found to be <0.02 absorption units after one month storage in 1 M HCl solution. The performance of the optical pH sensor was tested and the obtained pH values were compared with the results obtained using a pH meter device.

  6. Capacitance pressure sensor based on GaN high-electron-mobility transistor-on-Si membrane

    International Nuclear Information System (INIS)

    Kang, B.S.; Kim, J.; Jang, S.; Ren, F.; Johnson, J.W.; Therrien, R.J.; Rajagopal, P.; Roberts, J.C.; Piner, E.L.; Linthicum, K.J.; Chu, S.N.G.; Baik, K.; Gila, B.P.; Abernathy, C.R.; Pearton, S.J.

    2005-01-01

    The changes in the capacitance of the channel of an AlGaN/GaN high-electron-mobility transistor (HEMT) membrane structure fabricated on a Si substrate were measured during the application of both tensile and compressive strain through changes in the ambient pressure. The capacitance of the channel displays a change of 7.19±0.45x10 -3 pF/μm as a function of the radius of the membrane at a fixed pressure of +9.5 bar and exhibits a linear characteristic response between -0.5 and +1 bar with a sensitivity of 0.86 pF/bar for a 600 μm radius membrane. The hysteresis was 0.4% in the linear range. These AlGaN/GaN HEMT membrane-based sensors appear to be promising for both room-temperature and elevated-temperature pressure-sensing applications

  7. Biomimetic membranes for sensor and separation applications

    CERN Document Server

    2012-01-01

    This book addresses the possibilities and challenges in mimicking biological membranes and creating membrane-based sensor and separation devices. It covers recent advances in developing biomimetic membranes for technological applications with a focus on the use of integral membrane protein mediated transport. It describes the fundamentals of biosensing as well as separation and shows how the two processes work together in biological systems. The book provides an overview of the current state of the art, points to areas that need further investigation and anticipates future directions in the field. Biomimetics is a truly cross-disciplinary approach and this is exemplified by the challenges in mimicking osmotic processes as they occur in nature using aquaporin protein water channels as central building blocks. In the development of a biomimetic sensor/separation technology, both channel and carrier proteins are important and examples of how these may be reconstituted and controlled in biomimetic membranes are ...

  8. Highly Sensitive Temperature Sensors Based on Fiber-Optic PWM and Capacitance Variation Using Thermochromic Sensing Membrane.

    Science.gov (United States)

    Khan, Md Rajibur Rahaman; Kang, Shin-Won

    2016-07-09

    In this paper, we propose a temperature/thermal sensor that contains a Rhodamine-B sensing membrane. We applied two different sensing methods, namely, fiber-optic pulse width modulation (PWM) and an interdigitated capacitor (IDC)-based temperature sensor to measure the temperature from 5 °C to 100 °C. To the best of our knowledge, the fiber-optic PWM-based temperature sensor is reported for the first time in this study. The proposed fiber-optic PWM temperature sensor has good sensing ability; its sensitivity is ~3.733 mV/°C. The designed temperature-sensing system offers stable sensing responses over a wide dynamic range, good reproducibility properties with a relative standard deviation (RSD) of ~0.021, and the capacity for a linear sensing response with a correlation coefficient of R² ≈ 0.992 over a wide sensing range. In our study, we also developed an IDC temperature sensor that is based on the capacitance variation principle as the IDC sensing element is heated. We compared the performance of the proposed temperature-sensing systems with different fiber-optic temperature sensors (which are based on the fiber-optic wavelength shift method, the long grating fiber-optic Sagnac loop, and probe type fiber-optics) in terms of sensitivity, dynamic range, and linearity. We observed that the proposed sensing systems have better sensing performance than the above-mentioned sensing system.

  9. Highly Sensitive Temperature Sensors Based on Fiber-Optic PWM and Capacitance Variation Using Thermochromic Sensing Membrane

    Science.gov (United States)

    Khan, Md. Rajibur Rahaman; Kang, Shin-Won

    2016-01-01

    In this paper, we propose a temperature/thermal sensor that contains a Rhodamine-B sensing membrane. We applied two different sensing methods, namely, fiber-optic pulse width modulation (PWM) and an interdigitated capacitor (IDC)-based temperature sensor to measure the temperature from 5 °C to 100 °C. To the best of our knowledge, the fiber-optic PWM-based temperature sensor is reported for the first time in this study. The proposed fiber-optic PWM temperature sensor has good sensing ability; its sensitivity is ~3.733 mV/°C. The designed temperature-sensing system offers stable sensing responses over a wide dynamic range, good reproducibility properties with a relative standard deviation (RSD) of ~0.021, and the capacity for a linear sensing response with a correlation coefficient of R2 ≈ 0.992 over a wide sensing range. In our study, we also developed an IDC temperature sensor that is based on the capacitance variation principle as the IDC sensing element is heated. We compared the performance of the proposed temperature-sensing systems with different fiber-optic temperature sensors (which are based on the fiber-optic wavelength shift method, the long grating fiber-optic Sagnac loop, and probe type fiber-optics) in terms of sensitivity, dynamic range, and linearity. We observed that the proposed sensing systems have better sensing performance than the above-mentioned sensing system. PMID:27409620

  10. Artificial-enzyme gel membrane-based biosurveillance sensor with high reproducibility and long-term storage stability.

    Science.gov (United States)

    Ikeno, Shinya; Yoshida, Tetsuya; Haruyama, Tetsuya

    2009-02-01

    We propose that the most sophisticated strategy for primary biosurveillance is to exploit structural commonality through the detection of biologically relevant phosphoric substances. A novel assay, an artificial-enzyme membrane was designed and synthesized for sensor fabrication. This artificial-enzyme catalyzes the hydrolysis of the diphosphoric acid anhydride structure. This structure-selective, albeit not molecule-selective, catalytic hydrolysis was successfully coupled with amperometric detection. Since the catalytic reaction produces a dephosphorylation product (PO(4)(3-)), it can be reduced by an electrode potential of -250 mV vs. Ag/AgCl. Owing to the structural selectivity of the artificial-enzyme membrane, the sensor can detect biological phosphoric substances comprehensively that have the diphosphoric acid anhydride structure. The sensor successfully determined various biological phosphoric substances at concentrations in the micromolar (microM) to millimolar (mM) range, and it showed good functional stability and reproducibility in terms of sensor responses. This sensor was used to detect Escherichia coli lysed by heat treatment, and the response increased with increasing bacterial numbers. This unique technique for analyzing molecular commonality can be applied to the surveillance of biocontaminants, e.g. microorganisms, spores and viruses. Artificial-enzyme-based detection is a novel strategy for practical biosurveillance in the front line.

  11. Cobalt(II)-selective membrane sensor based on a [Me2(13)dieneN4] macrocyclic cobalt complex.

    Science.gov (United States)

    Singh, Ashok Kumar; Saxena, Puja; Mehtab, Sameena; Panwar, Amit

    2006-08-01

    A new poly(vinyl chloride)-based membrane was fabricated with the cobalt(II) complex of 2,4-dimethyl-1,5,8,11-tetraazacyclotrideca-1,4-diene [Me2(13)dieneN4] as an ion carrier. The membrane composition was Co2+ complex/PVC/NaTPB/DBP 15:50:15:20 (w/w). The sensor exhibited a Nernstian response for Co2+ ions over a wide concentration range (7.94x10(-6)-1.0x10(-1) M) at pH 2.5-7.0, a response time of 10 s, and it could be used for 3 months without any significant divergence in potential. The proposed membrane sensor exhibited good selectivity for Co2+ over a wide variety of other metal ions and in mixtures containing up to 25% (v/v) non-aqueous content. The sensor was successfully used as an indicator electrode in the potentiometric titration of Co2+ with EDTA and the direct determination of Co2+ in real samples.

  12. Experimental design of membrane sensor for selective determination of phenazopyridine hydrochloride based on computational calculations

    Energy Technology Data Exchange (ETDEWEB)

    Attia, Khalid A.M.; El-Abasawi, Nasr M.; Abdel-Azim, Ahmed H., E-mail: Ahmed.hussienabdelazim@hotmil.com

    2016-04-01

    Computational study has been done electronically and geometrically to select the most suitable ionophore to design a novel sensitive and selective electrochemical sensor for phenazopyridine hydrochloride (PAP). This study has revealed that sodium tetraphenylbarate (NaTPB) fits better with PAP than potassium tetrakis (KTClPB). The sensor design is based on the ion pair of PAP with NaTPB using dioctyl phthalate as a plasticizer. Under optimum conditions, the proposed sensor shows the slope of 59.5 mV per concentration decade in the concentration range of 1.0 × 10{sup −2}–1.0 × 10{sup −5} M with detection limit 8.5 × 10{sup −6} M. The sensor exhibits a very good selectivity for PAP with respect to a large number of interfering species as inorganic cations and sugars. The sensor enables track of determining PAP in the presence of its oxidative degradation product 2, 3, 6-Triaminopyridine, which is also its toxic metabolite. The proposed sensor has been successfully applied for the selective determination of PAP in pharmaceutical formulation. Also, the obtained results have been statistically compared to a reported electrochemical method indicating no significant difference between the investigated method and the reported one with respect to accuracy and precision. - Highlights: • Novel use of ISE for selective determination of phenazopyridine hydrochloride. • Investigating the degradation pathway of phenazopyridine with enough confirmation scan. • To avoid time-consuming and experimental trials, computational studies have been applied. • The proposed sensor shows high selectivity, reasonable detection limit and fast response.

  13. Experimental design of membrane sensor for selective determination of phenazopyridine hydrochloride based on computational calculations

    International Nuclear Information System (INIS)

    Attia, Khalid A.M.; El-Abasawi, Nasr M.; Abdel-Azim, Ahmed H.

    2016-01-01

    Computational study has been done electronically and geometrically to select the most suitable ionophore to design a novel sensitive and selective electrochemical sensor for phenazopyridine hydrochloride (PAP). This study has revealed that sodium tetraphenylbarate (NaTPB) fits better with PAP than potassium tetrakis (KTClPB). The sensor design is based on the ion pair of PAP with NaTPB using dioctyl phthalate as a plasticizer. Under optimum conditions, the proposed sensor shows the slope of 59.5 mV per concentration decade in the concentration range of 1.0 × 10 −2 –1.0 × 10 −5 M with detection limit 8.5 × 10 −6 M. The sensor exhibits a very good selectivity for PAP with respect to a large number of interfering species as inorganic cations and sugars. The sensor enables track of determining PAP in the presence of its oxidative degradation product 2, 3, 6-Triaminopyridine, which is also its toxic metabolite. The proposed sensor has been successfully applied for the selective determination of PAP in pharmaceutical formulation. Also, the obtained results have been statistically compared to a reported electrochemical method indicating no significant difference between the investigated method and the reported one with respect to accuracy and precision. - Highlights: • Novel use of ISE for selective determination of phenazopyridine hydrochloride. • Investigating the degradation pathway of phenazopyridine with enough confirmation scan. • To avoid time-consuming and experimental trials, computational studies have been applied. • The proposed sensor shows high selectivity, reasonable detection limit and fast response.

  14. Optimization of capacitive membrane sensors for surface-stress-based measurements

    NARCIS (Netherlands)

    Sajadi, B.; Goosen, J.F.L.; van Keulen, A.

    2017-01-01

    Surface stress-based measurement is a relatively new mechanism in biological and chemical sensing. The viability of this mechanism depends on the maximum sensitivity, accuracy, and precision that can be achieved with these sensors. In this paper, an analytical approximate solution and a

  15. A lutetium PVC membrane sensor based on (2-oxo-1,2--diphenylethylidene-N-phenylhydrazinecarbothioamide

    Directory of Open Access Journals (Sweden)

    HASSAN ALI ZAMANI

    2011-09-01

    Full Text Available Based on the former experience on the design and construction of metal ions sensors, especially those of high sensitivity for lanthanides, (2-oxo-1,2-diphenylethylidene-N-phenylhydrazinecarbothioamide (PHCT was used to construct a Lu3+ PVC sensor exhibiting a Nernstian slope of 19.8±0.3 mV dec-1. The sensor was found to function well over a concentration range of 1.0×10-2 and 1.0×10-6 mol L-1 of the target ion with a detection limit of 6.8×10-7 mol L-1. The sensor selectivity against many common alkaline, alkaline earth, transition, heavy metals and specially lanthanide ions was very good and it functioned well in the pH range 2.5–8.7. Having a lifetime of at least 2 months and a short response time of ≈ 5 s, the sensor was successfully used as an indicator electrode in the potentiometric titration of Lu3+.

  16. A Ho(III) potentiometric polymeric membrane sensor based on a new four dentate neutral ion carrier.

    Science.gov (United States)

    Zamani, Hassan Ali; Zanganeh-Asadabadi, Abbas; Rohani, Mitra; Zabihi, Mohammad Saleh; Fadaee, Javad; Ganjali, Mohammad Reza; Faridbod, Farnoush; Meghdadi, Soraia

    2013-03-01

    In this research, we report a new Ho(3+)-PVC membrane electrode based on N-(4,5-dimethyl-2-(picolinamido)phenyl)picolinamide (H(2)Me(2)bpb) as a suitable ion carrier. Poly vinylchloride (PVC)-based membrane composed of H(2)Me(2)bpb with oleic acid (OA) as anionic additives, and o-nitrophenyloctyl ether (NPOE) as plasticized solvent mediator. The sensor exhibits a Nernstian slope of 20.1 ± 0.2 mV decade(-1) over the concentration range of 1.0 × 10(-6) to 1.0 × 1(-2) mol L(-1), and a detection limit of 5.0 × 10(-7) mol L(-1) of Ho(3+) ions. The potentiometric response of the sensor is independent of the solution pH in the range of 3.5-9.4. It has a very short response time, in the whole concentration range (<10s), and can be used for at least eight weeks. The proposed electrode shows a good selectivity towards Ho(3+) ions over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. To assess its analytical applicability the proposed Ho(3+) sensor was successfully applied as an indicator electrode in the titration of Ho(3+) ion solutions in certified reference materials, alloy samples and for the determination of the fluoride ion in two mouthwash preparations. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Nanomechanical membrane-type surface stress sensor.

    Science.gov (United States)

    Yoshikawa, Genki; Akiyama, Terunobu; Gautsch, Sebastian; Vettiger, Peter; Rohrer, Heinrich

    2011-03-09

    Nanomechanical cantilever sensors have been emerging as a key device for real-time and label-free detection of various analytes ranging from gaseous to biological molecules. The major sensing principle is based on the analyte-induced surface stress, which makes a cantilever bend. In this letter, we present a membrane-type surface stress sensor (MSS), which is based on the piezoresistive read-out integrated in the sensor chip. The MSS is not a simple "cantilever," rather it consists of an "adsorbate membrane" suspended by four piezoresistive "sensing beams," composing a full Wheatstone bridge. The whole analyte-induced isotropic surface stress on the membrane is efficiently transduced to the piezoresistive beams as an amplified uniaxial stress. Evaluation of a prototype MSS used in the present experiments demonstrates a high sensitivity which is comparable with that of optical methods and a factor of more than 20 higher than that obtained with a standard piezoresistive cantilever. The finite element analyses indicate that changing dimensions of the membrane and beams can substantially increase the sensitivity further. Given the various conveniences and advantages of the integrated piezoresistive read-out, this platform is expected to open a new era of surface stress-based sensing.

  18. Preparation and characterization of a sulindac sensor based on PVC/TOA-SUL membrane.

    Science.gov (United States)

    Lenik, Joanna

    2014-04-01

    A potentiometric sulindac sensitive sensor based on tetraoctylammonium (Z)-5-fluoro-2-methyl-1-[[p-(methylsulfinyl)phenyl]methylene]-1H-indene-3-acetate (TOA-SUL) was described. The electrode responded with sensitivity of 57.5±1.6mV decade(-1) over the linear range 5×10(-5)-1×10(-2)mol L(-1) at pH6.0-9.0. It had the limit of detection 1.4×10(-5)mol L(-1), a fast response time of 13s and showed clear discrimination of sulindac ions from several inorganic and organic compounds and also amino acids. This electrode did not contain any inner solutions, so it was easy and comfortable to use. The proposed sensor was used to determine sulindac in clear solution and in urine sample solution. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Aggressive media exposed differential pressure sensor with a deposited membrane

    DEFF Research Database (Denmark)

    Bouaidat, Salim; Eriksen, Gert Friis; Reus, Roger De

    2001-01-01

    A new piezoresistive differential pressure sensor design for harsh wet environments is presented. The sensor design is based on a deposited membrane, which is deposited on top of polysilicon interconnects and piezoresistors. Flat membrane surfaces are thereby achieved. This enables thin film...

  20. Biomimetic membranes for sensor and separation applications

    DEFF Research Database (Denmark)

    Helix Nielsen, Claus

    2009-01-01

    membrane-based sensor and/or separation devices? In the development of biomimetic sensor/separation technology, both channels (ion and water channels) and carriers (transporters) are important. Generally, each class of transport proteins conducts specific molecular species in and out of the cell while...... generally have a lower turnover but are capable of transport against gradients. For both classes of proteins, their unique flux-properties make them interesting as candidates in biomimetic sensor/separation devices. An ideal sensor/separation device requires the supporting biomimetic matrix to be virtually...... impermeable to anything but the solute in question. In practice, however, a biomimetic support matrix will generally have finite permeabilities to water, electrolytes, and non-electrolytes. The feasibility of a biomimetic device thus depends on the relative transport contribution from both protein...

  1. Smart membranes for monitoring membrane based desalination processes

    KAUST Repository

    Laleg-Kirati, Taous-Meriem

    2017-10-12

    Various examples are related to smart membranes for monitoring membrane based process such as, e.g., membrane distillation processes. In one example, a membrane, includes a porous surface and a plurality of sensors (e.g., temperature, flow and/or impedance sensors) mounted on the porous surface. In another example, a membrane distillation (MD) process includes the membrane. Processing circuitry can be configured to monitor outputs of the plurality of sensors. The monitored outputs can be used to determine membrane degradation, membrane fouling, or to provide an indication of membrane replacement or cleaning. The sensors can also provide temperatures or temperature differentials across the porous surface, which can be used to improve modeling or control the MD process.

  2. Colorimetric Humidity Sensors Based on Electrospun Polyamide/CoCl2 Nanofibrous Membranes

    Science.gov (United States)

    You, Ming-Hao; Yan, Xu; Zhang, Jun; Wang, Xiao-Xiong; He, Xiao-Xiao; Yu, Miao; Ning, Xin; Long, Yun-Ze

    2017-05-01

    Humidity indicators based on composite polyamide 66/cobalt chloride (PA66/CoCl2) nanofibrous membranes (NFMs) were successfully fabricated by electrospinning. A series of NFMs with various weight percentage of CoCl2 to PA66 were prepared, and their humidity sensitivity based on color changing and quartz crystal microbalance (QCM) were studied. Due to the color change property of cobalt chloride, the as-spun composite NFMs show obviously macroscopic color change from blue to pink as relative humidity (RH) increasing from 12.4 to 97.2%. Moreover, the QCM detection showed a linear dependence on the RH changing and exhibited short response/recovery time (less than 65.4 s/11 s), small hysteresis (less than 11%), good reproducibility, and stability. Owing to the above double sensitive mechanism on RH, the PA66/CoCl2 composite NFM may show great potential applications from meticulous to coarse.

  3. ISFET based enzyme sensors

    NARCIS (Netherlands)

    van der Schoot, Bart H.; Bergveld, Piet

    1987-01-01

    This paper reviews the results that have been reported on ISFET based enzyme sensors. The most important improvement that results from the application of ISFETs instead of glass membrane electrodes is in the method of fabrication. Problems with regard to the pH dependence of the response and the

  4. Europium (III) PVC membrane sensor based on N-pyridine-2-carboxamido-8-aminoquinoline as a sensing material

    International Nuclear Information System (INIS)

    Zamani, Hassan Ali; Kamjoo, Rahman; Mohammadhosseini, Majid; Zaferoni, Mojdeh; Rafati, Zynab; Ganjali, Mohammad Reza; Faridbod, Farnoush; Meghdadi, Soraia

    2012-01-01

    Conductometric study in acetonitrile solution shows the selectivity of PCQ toward europium ion. Therefore, a new europium PVC membrane electrode was prepared based on N-pyridine-2-carboxamido-8-aminoquinoline (PCQ) as an ion carrier. The electrode has a wide concentration range from 1.0 × 10 −2 and 1.0 × 10 −6 mol L −1 , Nernstian slope of 19.8 ± 0.3 mV per decade and a detection limit of 6.4 × 10 −7 mol L −1 . The potentiometric response is pH independent in the range of 2.4–7.4. The proposed sensor has a relatively fast response time less than 10 s and it can be used for at least 2 months without any considerable divergence in its potentials. The proposed electrode revealed good selectivity toward europium ion in comparison with variety of other metal ions. The practical utility of the electrodes has been demonstrated by their use as indicator electrodes in the potentiometric titration of Eu 3+ ions with EDTA and for determination of Eu 3+ ion concentration in mixtures of two and three different ions. - Highlights: ► A new ion carrier is introduced to preparation of a selective sensor for Eu 3+ ions. ► This technique is very simple and it's not necessary to use sophisticated equipment. ► The novelty of this work is the high affinity of the ionophore toward the Eu 3+ ions. ► The sensor is superior to the formerly reported Eu 3+ sensors in terms of selectivity.

  5. Neodymium(III PVC Membrane Electrodchemical Sensor Based on N-benzoylethylidene-2-aminobenzylamine

    Directory of Open Access Journals (Sweden)

    Hassan Ali Zamani

    2012-01-01

    Full Text Available The N-benzoylethylidene-2-aminobenzylamine (BEA was used as a suitable ionophore in construction of neodymium ion selective electrode. The electrode with composition of 30% PVC, 58% solvent mediator (NB, 2% ionophore (BEA and 10% anionic additive (OA shows the best potentiometric response characteristics. The Nd3+ sensor exhibits a Nernstian slope of 21.2 ± 0.2 mV decade-1 over the concentration range of 1.0 × 10-6 to 1.0 × 10-2 mol L-1, and a detection limit of 6.3 × 10-7 mol L-1 of Nd3+ ions. The potentiometric response of the sensor is independent of the solution pH in the range of 2.4–8.5. It has a very short response time, in the whole concentration range (~7 s, and can be used for at least eight weeks. The proposed sensor revealed high selectivity with respect to all common alkali, alkaline earth, transition and heavy metal ions, including members of the lanthanide family other than Nd3+. The Nd3+ sensor was successfully applied as an indicator electrode in the potentiometric titration of Nd3+ ions with EDTA. The electrode was also employed for the determination of the fluoride ion in two mouth wash preparations.

  6. An optical sensor for the determination of digoxin in serum samples based on a molecularly imprinted polymer membrane

    Energy Technology Data Exchange (ETDEWEB)

    Paniagua Gonzalez, Gema [Departamento de Ciencias Analiticas, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia (UNED), 28040 Madrid (Spain); Fernandez Hernando, Pilar, E-mail: pfhernando@ccia.uned.es [Departamento de Ciencias Analiticas, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia (UNED), 28040 Madrid (Spain); Durand Alegria, J. S. [Departamento de Ciencias Analiticas, Facultad de Ciencias, Universidad Nacional de Educacion a Distancia (UNED), 28040 Madrid (Spain)

    2009-04-13

    This paper reports the synthesis and testing of a molecularly imprinted polymer membrane for digoxin analysis. Digoxin-specific bulk polymer was obtained by the UV initiated co-polymerisation of methacrylic acid and ethylene glycol dimethacrylate in acetonitrile as porogen. After extracting the template analyte, the ground polymer particles were mixed with plasticizer polyvinyl chloride to form a MIP membrane. A reference polymer membrane was prepared from the same mixture of monomers but with no template. The resultant membrane morphologies were examined by scanning electron microscopy. The imprinted membrane was tested as the recognition element in a digoxin-sensitive fluorescence sensor; sensor response was measured using standard solutions of digoxin at concentrations of up to 4 x 10{sup -3} mg L{sup -1}. The detection limit was 3.17 x 10{sup -5} mg L{sup -1}. Within- and between-day relative standard deviations RSD (n = 5) were in the range 4.5-5.5% and 5.5-6.5% respectively for 0 and 1 x 10{sup -3} mg L{sup -1} digoxin concentrations. A selectivity study showed that compounds of similar structure to digoxin did not significantly interfere with detection for interferent concentrations at 10, 30 and 100 times higher than the digoxin concentration. This simply manufactured MIP membrane showed good recognition characteristics, a high affinity for digoxin, and provided satisfactory results in analyses of this analyte in human serum.

  7. An optical sensor for the determination of digoxin in serum samples based on a molecularly imprinted polymer membrane

    International Nuclear Information System (INIS)

    Paniagua Gonzalez, Gema; Fernandez Hernando, Pilar; Durand Alegria, J. S.

    2009-01-01

    This paper reports the synthesis and testing of a molecularly imprinted polymer membrane for digoxin analysis. Digoxin-specific bulk polymer was obtained by the UV initiated co-polymerisation of methacrylic acid and ethylene glycol dimethacrylate in acetonitrile as porogen. After extracting the template analyte, the ground polymer particles were mixed with plasticizer polyvinyl chloride to form a MIP membrane. A reference polymer membrane was prepared from the same mixture of monomers but with no template. The resultant membrane morphologies were examined by scanning electron microscopy. The imprinted membrane was tested as the recognition element in a digoxin-sensitive fluorescence sensor; sensor response was measured using standard solutions of digoxin at concentrations of up to 4 x 10 -3 mg L -1 . The detection limit was 3.17 x 10 -5 mg L -1 . Within- and between-day relative standard deviations RSD (n = 5) were in the range 4.5-5.5% and 5.5-6.5% respectively for 0 and 1 x 10 -3 mg L -1 digoxin concentrations. A selectivity study showed that compounds of similar structure to digoxin did not significantly interfere with detection for interferent concentrations at 10, 30 and 100 times higher than the digoxin concentration. This simply manufactured MIP membrane showed good recognition characteristics, a high affinity for digoxin, and provided satisfactory results in analyses of this analyte in human serum.

  8. Synthetic Biomimetic Membranes and Their Sensor Applications

    Directory of Open Access Journals (Sweden)

    Young-Rok Kim

    2012-07-01

    Full Text Available Synthetic biomimetic membranes provide biological environments to membrane proteins. By exploiting the central roles of biological membranes, it is possible to devise biosensors, drug delivery systems, and nanocontainers using a biomimetic membrane system integrated with functional proteins. Biomimetic membranes can be created with synthetic lipids or block copolymers. These amphiphilic lipids and polymers self-assemble in an aqueous solution either into planar membranes or into vesicles. Using various techniques developed to date, both planar membranes and vesicles can provide versatile and robust platforms for a number of applications. In particular, biomimetic membranes with modified lipids or functional proteins are promising platforms for biosensors. We review recent technologies used to create synthetic biomimetic membranes and their engineered sensors applications.

  9. Towards Enhanced Gas Sensor Performance with Fluoropolymer Membranes

    Directory of Open Access Journals (Sweden)

    Thorsten Graunke

    2016-09-01

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

  10. Graphene based piezoresistive pressure sensor

    NARCIS (Netherlands)

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

    2013-01-01

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

  11. Construction and evaluation of PVC and sol-gel sensor membranes based on Mn(III)TPP-Cl. Application to valproate determination in pharmaceutical preparations.

    Science.gov (United States)

    Santos, Emília M G; Araújo, Alberto N; Couto, Cristina M C M; Montenegro, M Conceição B S M

    2006-02-01

    The construction and general performance of new valproate-selective electrodes based on manganese(III) tetraphenylporphyrin [Mn(III)TPP-Cl], as an ionophore, are presented. The ionophore was incorporated into PVC and ceramic membranes (sol-gel) based on methyltriethoxysilane. The influence of membrane composition and pH and the effect of lipophilic cationic and anionic additives in PVC membranes were investigated concerning their influence on the slope, response time, selectivity and lifetime of the electrodes. The PVC membrane without additive and the sol-gel membrane presented slopes and practical limits of detection of -60.8 mV dec(-1) and 5x10(-6) mol l(-1) and -60.3 mV dec(-1) and 1x10(-4) mol l(-1), respectively. The sol-gel membranes displayed higher selectivity for valproate when compared with PVC membranes. These two types of electrodes were coupled to a sequential-injection analysis (SIA) system for the direct determination of valproate in pharmaceutical formulations. The association of Mn(III)TPP-Cl with the sol-gel support inserted in a SIA system provided potentiometric sensors with an analytical range of 1x10(-3)-5x10(-2) mol l(-1), with a sample rate of 55 samples per hour and a sample and carrier consumption of 140 and 2,500 microl per determination, respectively.

  12. Synthesis of N'-(1-pyridin-2-ylmethylene)-2-furohydrazide and its application in construction of a highly selective PVC-based membrane sensor for La(III) ions.

    Science.gov (United States)

    Zamani, Hassan Ali; Ganjali, Mohammad Reza; Norouzi, Parviz; Adib, Mahdi; Aceedy, Mohammad

    2006-07-01

    A highly La(III) ion-selective PVC membrane sensor based on N'-(1-pyridin-2-ylmethylene)-2-furohydrazide (NPYFH) as an excellent sensing material was successfully developed. The electrode shows a good selectivity for La(III) ion with respect to most common cations including alkali, alkaline earth, transition and heavy metal ions. The proposed sensor exhibits a wide linear response with slope of 19.2 +/- 0.6 mV per decade over the concentration range of 1.0 x 10(-6) - 1.0 x 10(-1) M, and a detection limit of 7.0 x 10(-7) M of La(III) ions. The sensor response is independent of pH in the range of 3.5-10.0. The proposed electrode was applied as an indicator electrode in potentiometric titration of La(III) ion with EDTA.

  13. Developments in the Field of Conducting and Non-conducting Polymer Based Potentiometric Membrane Sensors for Ions Over the Past Decade

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Ganjali

    2008-04-01

    Full Text Available Many research studies have been conducted on the use of conjugated polymers in the construction of chemical sensors including potentiometric, conductometric and amperometric sensors or biosensors over the last decade. The induction of conductivity on conjugated polymers by treating them with suitable oxidizing agents won Heeger, MacDiarmid and Shirakawa the 2000 Nobel Prize in Chemistry. Common conjugated polymers are poly(acetylenes, poly(pyrroles, poly(thiophenes, poly(terthiophenes, poly(anilines, poly(fluorines, poly(3-alkylthiophenes, polytetrathiafulvalenes, polynapthalenes, poly(p-phenylene sulfide, poly(p-phenylenevinylenes, poly(3,4-ethylenedioxythiophene, polyparaphenylene, polyazulene, polyparaphenylene sulfide, polycarbazole and polydiaminonaphthalene. More than 60 sensors for inorganic cations and anions with different characteristics based on conducting polymers have been reported. There have also been reports on the application of non-conducting polymers (nCPs, i.e. PVC, in the construction of potentiometric membrane sensors for determination of more than 60 inorganic cations and anions. However, the leakage of ionophores from the membranes based on these polymers leads to relatively lower life times. In this article, we try to give an overview of Solid-Contact ISE (SCISE, Single-Piece ISE (SPISE, Conducting Polymer (CP-Based, and also non-conducting polymer PVC-based ISEs for various ions which their difference is in the way of the polymer used with selective membrane. In SCISEs and SPISEs, the plasticized PVC containing the ionophore and ionic additives govern the selectivity behavior of the electrode and the conducting polymer is responsible of ion-to-electron transducer. However, in CPISEs, the conducting polymer layer is doped with a suitable ionophore which enhances the ion selectivity of the CP while its redox response has to be suppressed.

  14. Developments in the Field of Conducting and Non-conducting Polymer Based Potentiometric Membrane Sensors for Ions Over the Past Decade.

    Science.gov (United States)

    Faridbod, Farnoush; Norouzi, Parviz; Dinarvand, Rassoul; Ganjali, Mohammad Reza

    2008-04-03

    Many research studies have been conducted on the use of conjugated polymers in the construction of chemical sensors including potentiometric, conductometric and amperometric sensors or biosensors over the last decade. The induction of conductivity on conjugated polymers by treating them with suitable oxidizing agents won Heeger, MacDiarmid and Shirakawa the 2000 Nobel Prize in Chemistry. Common conjugated polymers are poly(acetylene)s, poly(pyrrole)s, poly(thiophene)s, poly(terthiophene)s, poly(aniline)s, poly(fluorine)s, poly(3-alkylthiophene)s, polytetrathiafulvalenes, polynapthalenes, poly(p-phenylene sulfide), poly(p-phenylenevinylene)s, poly(3,4-ethylenedioxythiophene), polyparaphenylene, polyazulene, polyparaphenylene sulfide, polycarbazole and polydiaminonaphthalene. More than 60 sensors for inorganic cations and anions with different characteristics based on conducting polymers have been reported. There have also been reports on the application of non-conducting polymers (nCPs), i.e. PVC, in the construction of potentiometric membrane sensors for determination of more than 60 inorganic cations and anions. However, the leakage of ionophores from the membranes based on these polymers leads to relatively lower life times. In this article, we try to give an overview of Solid-Contact ISE (SCISE), Single-Piece ISE (SPISE), Conducting Polymer (CP)-Based, and also non-conducting polymer PVC-based ISEs for various ions which their difference is in the way of the polymer used with selective membrane. In SCISEs and SPISEs, the plasticized PVC containing the ionophore and ionic additives govern the selectivity behavior of the electrode and the conducting polymer is responsible of ion-to-electron transducer. However, in CPISEs, the conducting polymer layer is doped with a suitable ionophore which enhances the ion selectivity of the CP while its redox response has to be suppressed.

  15. Detecting Levels of Polyquaternium-10 (PQ-10) via Potentiometric Titration with Dextran Sulphate and Monitoring the Equivalence Point with a Polymeric Membrane-Based Polyion Sensor.

    Science.gov (United States)

    Ferguson, Stephen A; Wang, Xuewei; Meyerhoff, Mark E

    2016-08-07

    Polymeric quaternary ammonium salts (polyquaterniums) have found increasing use in industrial and cosmetic applications in recent years. More specifically, polyquaternium-10 (PQ-10) is routinely used in cosmetic applications as a conditioner in personal care product formulations. Herein, we demonstrate the use of potentiometric polyion-sensitive polymeric membrane-based electrodes to quantify PQ-10 levels. Mixtures containing both PQ-10 and sodium lauryl sulfate (SLS) are used as model samples to illustrate this new method. SLS is often present in cosmetic samples that contain PQ-10 (e.g., shampoos, etc.) and this surfactant species interferes with the polyion sensor detection chemistry. However, it is shown here that SLS can be readily separated from the PQ-10/SLS mixture by use of an anion-exchange resin and that the PQ-10 can then be titrated with dextran sulphate (DS). This titration is monitored by potentiometric polyanion sensors to provide equivalence points that are directly proportional to PQ-10 concentrations.

  16. A novel, fast responding, low noise potentiometric sensor containing a carbon-based polymeric membrane for measuring surfactants in industrial and environmental applications.

    Science.gov (United States)

    Samardžić, Mirela; Galović, Olivera; Hajduković, Mateja; Sak-Bosnar, Milan

    2017-01-01

    A new high-sensitivity potentiometric sensor for anionic surfactants was fabricated using the dimethyldioctadecylammonium-tetraphenylborate (DDA-TPB) ion associate as an ionophore that was incorporated into a liquid PVC membrane. Carbon powder was used for immobilization of the ionophore in the membrane, thus significantly reducing its ohmic resistance and reducing its signal drift. The sensor exhibits a sub-Nernstian response for both dodecylbenzenesulfonate (DBS) and dodecyl sulfate (DS) in H 2 O (55.3 and 58.5mV/decade of activity, respectively) in a range between 3.2×10 -7 and 4.6×10 -3 M for DS and 2.5×10 -7 and 1.2×10 -3 M for DBS. The sensor also exhibited a sub-Nernstian response for DS and DBS in 10mM Na 2 SO 4 (55.4 and 57.7mV/decade of activity, respectively) between 2.5×10 -7 and 4.6×10 -3 M for DS and 1.5×10 -7 and 8.8×10 -4 M for DBS. The detection limits for DS and DBS in H 2 O were 2.5×10 -7 and 2.0×10 -7 M and in 10mM Na 2 SO 4 the detection limits were 2.5×10 -7 and 1.2×10 -7 M, respectively. The response time of the sensor was less than 5s for changes at higher concentration levels (above 1×10 -4 M) in both water and 10mM Na 2 SO 4. At lower concentrations (below 1×10 -5 M) the response times were 8 and 6s in water and 10mM Na 2 SO 4 , respectively. The signal drift of the sensor was 1.2mV/hour. The new carbon-based sensor exhibited excellent selectivity performance for DS over almost all of the anions commonly present in commercial formulations and it was successfully employed as an end-point detector in potentiometric titrations of anionic surfactants in a pH range from 3 to 12. Three-component mixtures containing sodium alkanesulfonate (C 10 , C 12 and C 14 ) were successfully differentially titrated. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Zinc(II PVC-based membrane sensor based on 5,6-benzo-4,7,13,16,21,24- hexaoxa-1,10-diazabicyclo[8,8,8]hexacos-5-ene

    Directory of Open Access Journals (Sweden)

    Zamani Hassan Ali

    2006-01-01

    Full Text Available The 5,6-benzo-4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8,8,8]hexacos-5-ene (BHDE was used as an excellent ionophore in construction of a Zn(II PVC-based membrane sensor. The best performance was obtained with a membrane composition of 30% poly(vinyl chloride, 64.5% nitrobenzen (NB, 2.5% BHDE and 3% sodium tetraphenylborate (NaTPB. This sensor shows very good selectivity and sensitivity towards zinc ion over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The sensor revealed a great enhancement in selectivity coefficients for zinc ions, in comparison to the previously reported zinc sensors. The proposed sensor exhibits a Nernstian behavior (with slope of 29.1 ? 0.4 mV per decade over a wide concentration range (1.0 10-6-1.0 10-1 mol L-1 with a detection limit of 6.3 x10-7 mol L-1 (41.2 ng mL-1. It shows relatively fast response time, in the whole concentration range (< 10s, and can be used for at least 10 weeks in a pH range of 2.8-7.3. The proposed sensor was successfully used in direct determination of zinc ions in wastewater of industrial zinc electroplating companies, and also as an indicator electrode in titration with EDTA.

  18. Synthesis of a new oxime and its application to the construction of a highly selective and sensitive Co(II) PVC-based membrane sensor.

    Science.gov (United States)

    Ganjali, Mohammad Reza; Mizani, Farhang; Emami, Mehdi; Darjezini, Maryam; Darvich, Mohammad Raouf; Yousefi, Mohammad

    2004-03-01

    A cobalt(II) ion-selective membrane sensor has been fabricated from a poly vinyl chloride (PVC) matrix membrane containing a new oxime compound (oxime of 1-(2-oxocyclohexyl)-1,2-cyclohexanediol, OXCCD) as a neutral carrier, sodium tetraphenyl borate (NaTPB) as an anionic excluder and o-nitrophenyloctylether (o-NPOE) as a plasticizing solvent mediator. The membrane sensor exhibits a linear potential response in the concentration range of 1.0 x 10(-1) - 1.0 x 10(-6) M of Co2+. The electrode displays a Nernstian slope of 29.8 mV decade(-1) in the pH range of 3.5 - 8.0. The sensor also exhibits a fast response time of < 25 s. The detection limit of the proposed sensor is 9.0 x 10(-7) M (approximately 40 ng/ml), and it can be used over a period of two months. The selectivity of the sensor with respect to other cations (alkali, alkaline earth, transition and heavy metal ions) is excellent. The practical utility of the sensor has been demonstrated by using it as an indicator electrode in the potentiometric titration of Co2+ with EDTA and for the direct determination of Co(II) in wastewater of the electroplating industry.

  19. A sensitive optical micro-machined ultrasound sensor (OMUS) based on a silicon photonic ring resonator on an acoustical membrane

    NARCIS (Netherlands)

    Leinders, S.M.; Westerveld, W.J.; Pozo, J.; Neer, P.L.M.J.; Snyder, B.; O'Brien, P.; Urbach, H.P.; de Jong, N.; Verweij, M.D.

    2015-01-01

    With the increasing use of ultrasonography, especially in medical imaging, novel fabrication techniques together with novel sensor designs are needed to meet the requirements for future applications like three-dimensional intercardiac and intravascular imaging. These applications require arrays of

  20. A sensitive optical micro-machined ultrasound sensor (OMUS) based on a silicon photonic ring resonator on an acoustical membrane

    NARCIS (Netherlands)

    S.M. Leinders (Suzanne); W.J. Westerveld; J. Pozo; P.L.M.J. van Neer (Paul); B. Snyder; P. O'Brien; H.P. Urbach (H.); N. de Jong (Nico); M.D. Verweij (Martin)

    2015-01-01

    textabstractWith the increasing use of ultrasonography, especially in medical imaging, novel fabrication techniques together with novel sensor designs are needed to meet the requirements for future applications like three-dimensional intercardiac and intravascular imaging. These applications require

  1. Development of a novel pH sensor based upon Janus Green B immobilized on triacetyl cellulose membrane: Experimental design and optimization

    Science.gov (United States)

    Chamkouri, Narges; Niazi, Ali; Zare-Shahabadi, Vali

    2016-03-01

    A novel pH optical sensor was prepared by immobilizing an azo dye called Janus Green B on the triacetylcellulose membrane. Condition of the dye solution used in the immobilization step, including concentration of the dye, pH, and duration were considered and optimized using the Box-Behnken design. The proposed sensor showed good behavior and precision (RSD < 5%) in the pH range of 2.0-10.0. Advantages of this optical sensor include on-line applicability, no leakage, long-term stability (more than 6 months), fast response time (less than 1 min), high selectivity and sensitivity as well as good reversibility and reproducibility.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  3. Potentiometric Membrane Sensors for Levamisole Determination

    Directory of Open Access Journals (Sweden)

    Natalia Zubenya

    2016-11-01

    Full Text Available The ion pair (IP of levamisole with BiI4-(SbI4- for the levamisole-selective sensor with a PVC membrane containing - ions were developed. Thermal behavior of obtained IP was investigated by differential thermal analysis that would show the thermal stability and the character of the decomposition of the complex. The thermolysis of Lev+BiI4- IP undergoes three stages that fit a theoretical interpretation. the linearity ranges of levamisole sensors function are 7.9 ×10-6 – 1×10-1 (7.9 ×10-5 – 1×10-1 M. The Nernstian slope of                   50.6 – 53.4 mV pC−1 and detection limit of 5.0 × 10−5 – 1.5 × 10−4 M. The working range of pH is 2.8 – 6.0.     The efficiency of the use of electrodes for levamisole content control in pharmaceutical preparations was shown by direct potentiometry and potentiometric titration methods.

  4. Trace hydrogen sulfide gas sensor based on tungsten sulfide membrane-coated thin-core fiber modal interferometer

    Science.gov (United States)

    Deng, Dashen; Feng, Wenlin; Wei, Jianwei; Qin, Xiang; Chen, Rong

    2017-11-01

    A novel fiber-optic hydrogen sulfide sensor based on a thin-core Mach-Zehnder fiber modal interferometer (TMZFI) is demonstrated and fabricated. This in-line interferometer is composed of a short section of thin-core fiber sandwiched between two standard single mode fibers, and the fast response to hydrogen sulfide is achieved via the construction of tungsten sulfide film on the outside surface of the TMZFI using the dip-coating and calcination technique. The fabricated sensing nanofilm is characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) spectrometer, Fourier transform infrared (FTIR) and spectroscopic analysis technology, etc. Experimental results showed that the WS2 sensing film has a hexagonal structure with a compact and porous morphology. The XPS and FTIR indicate that the existence of two elements (W and S) is demonstrated. With the increasing concentration of hydrogen sulfide, the interference spectra appear blue shift. In addition, a high sensitivity of 18.37 pm/ppm and a good linear relationship are obtained within a measurement range from 0 to 80 ppm. In addition, there is an excellent selectivity for H2S, which has also been proved by the surface adsorption energy results of tungsten sulfide with four gases (H2S, N2, O2 and CO2) by using the density functional theory calculations. This interferometer has the advantages of simple structure, high sensitivity and easy manufacture, and could be used in the safety monitoring field of hydrogen sulfide gas.

  5. A cerium(III) selective polyvinyl chloride membrane sensor based on a Schiff base complex of N,N'-bis[2-(salicylideneamino)ethyl]ethane-1,2-diamine

    International Nuclear Information System (INIS)

    Gupta, Vinod Kumar; Singh, A.K.; Gupta, Barkha

    2006-01-01

    A polyvinyl chloride (PVC) based membrane sensor for cerium ions was prepared by employing N,N'-bis[2-(salicylideneamino)ethyl]ethane-1,2-diamine as an ionophore, oleic acid (OA) as anion excluder and o-nitrophenyloctyl ether (o-NPOE) as plasticizer. The plasticized membrane sensor exhibits a Nernstian response for Ce(III) ions over a wide concentration range (1.41 x 10 -7 to 1.0 x 10 -2 M) with a limit of detection as low as 8.91 x 10 -8 M. It has a fast response time (<10 s) and can be used for 4 months. The sensor revealed a very good selectivity with respect to common alkali, alkaline earth and heavy metal ions. The response of the proposed sensor is independent of pH between 3.0 and 8.0. It was used as an indicator electrode in potentiometric titration of fluoride, carbonate and oxalate anions and determination of cerium in simulated mixtures

  6. Monitoring of praseodymium(III) ions in aqueous solutions, soil and sediment samples by a PVC membrane sensor based on a furan-triazole derivative

    Energy Technology Data Exchange (ETDEWEB)

    Pourjavid, Mohammad Reza [Islamic Azad University, Tehran (Iran, Islamic Republic of). Dept. of Medicinal Chemistry. Nuclear Science and Technology Research Institute; Rezaee, Mohammad; Hosseini, Majid Haji [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of); Razavi, Taherehsadat, E-mail: pourjavid@gmail.com [Research Institute of Petroleum Industry, Tehran (Iran, Islamic Republic of). Instrumental Analysis Dept.

    2012-07-01

    A furan-triazole derivative has been explored as an ionophore for preparation of a highly selective Pr(III) membrane sensor. The proposed sensor exhibits a Nernstian response for Pr(III) activity over a wide concentration range with a detection limit of 5.2 x 10{sup -8}M. Its response is independent of pH of the solution in the range 3.0-8.8 and offers the advantages of fast response time. To investigate the analytical applicability of the sensor, it was applied successfully as an indicator electrode in potentiometric titration of Pr(III) solution and also in the direct and indirect determination of trace Pr(III) ions in some samples. (author)

  7. TiO2 Nanotubes Membrane Flexible Sensor for Low-Temperature H2S Detection

    Directory of Open Access Journals (Sweden)

    Patricia María Perillo

    2016-08-01

    Full Text Available This paper presents the fabrication and characterization of a flexible gas sensor based on TiO2 nanotubes membrane, onto which array interdigitated gold electrodes in one side and a common heater in the backside were obtained using conventional microfabrication techniques. This was used to detect hydrogen sulphide within a concentration range of 6–38 ppm. The response to low concentrations of H2S at low temperature and good stability make the sensor a promising candidate for practical applications. These results support the proposal that the TiO2 nanotubes membrane flexible sensors are promising in portable on-site detection based on low cost nanomaterials.

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

    Science.gov (United States)

    Wang, Qiugu; Hong, Wei; Dong, Liang

    2016-03-01

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

  9. Comparative studies of neodymium (III)-selective PVC membrane sensors

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Vinod K., E-mail: vinodfcy@iitr.ernet.in [Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667 (India); Goyal, Rajendra N.; Sharma, Ram A. [Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667 (India)

    2009-08-04

    Sensors based on two neutral ionophores, N,N'-bis((1H-pyrrol-2-yl)methylene)cyclohexane-1,2-diamine (L{sub 1}) and 3,3'-(cyclohexane-1,2-diylbis(azan-1-yl-1-ylidene) bis(methan-1-yl-1-ylidene)bis(5-hydroxymethyl)pyridine-2-ol) (L{sub 2}) are described for quantification of neodymium (III). Effect of various plasticizers; 2-nitrophenyloctylether (o-NPOE), dibutyl butylphosphonate (DBBP), tri-n-butyl phosphates (TBP), dioctylpthalate (DOP) and chloronapthalen (CN) and anion excluder, sodiumtetraphenylborate (NaTPB) has been studied. The membrane composition of PVC:o-NPOE:ionophore (L{sub 1}):NaTPB (w/w; mg) of 150:300:5:5 exhibited best performance. The sensor with ionophore (L{sub 1}) exhibits significantly enhanced selectivity towards neodymium (III) in the concentration range 5.0 x 10{sup -7} to 1.0 x 10{sup -2} M with a detection limit of 1.0 x 10{sup -7} M and a Nernstian compliance (19.8 {+-} 0.3 mV decade{sup -1} of activity) within pH range 4.0-8.0. The response time of sensor was found as 10 s. The influence of the membrane composition and possible interfering ions has also been investigated on the response properties of the electrode. The fast and stable response, good reproducibility and long-term stability of the sensor are observed. The sensor has been found to work satisfactorily in partially non-aqueous media up to 20% (v/v) content of methanol, ethanol or acetonitrile and could be used for a period of 3 months. The selectivity coefficients determined by using fixed interference method (FIM) indicate high selectivity for neodymium. The proposed electrode shows fairly good discrimination of neodymium (III) from other cations. The application of prepared sensor has been demonstrated in the determination of neodymium (III) in spiked water samples.

  10. PVC Membrane Sensors for Potentiometric Determination of Acebutolol

    Directory of Open Access Journals (Sweden)

    Abdulrahman Al-Majed

    2007-12-01

    Full Text Available The construction and general performance characteristics of two novelpotentiometric membrane sensors responsive to the acebutolol are described. Thesensors are based on the use of ion-association complexes of acebutolol (AC withtetraphenylborate(TPB (I and phosphomolybdate(PM (II as exchange sites in a PVCmatrix. The sensors show a fast, stable and near- Nernstian for the mono charge cationof AC over the concentration range 1×10-3 - ~10-6 M at 25 °C over the pH range 2.0 -6.0 with cationic slope of 51.5 ± 0.5 and 53.0 ± 0.5 per concentration decade for AC-Iand AC-II sensors respectively. The lower detection limit is 6×10-6 M and 4×0-6 M withthe response time 20-30 s in the same order of both sensors. Selectivity coefficients ofAC related to a number of interfering cation and some organic compounds wereinvestigated. There are negligible interferences are caused by most of the investigatedspecies. The direct determination of 3 - 370 μg/ml of AC shows an average recovery of 99.4 and 99.5% and a mean relative standard deviation of 1 . 5 % at 100.0 μg/ml forsensor I and II respectively. The results obtained by determination of AC in tablets usingthe proposed sensors which comparable favorably with those obtained by the Britishpharmacopoeia method. In the present investigation the electrodes have been utilized asend point indicator for some precipitation titration reactions.

  11. Highly selective and sensitive optical sensor for determination of Pb2+and Hg2+ ions based on the covalent immobilization of dithizone on agarose membrane

    Science.gov (United States)

    Zargoosh, Kiomars; Babadi, Fatemeh Farhadian

    2015-02-01

    A highly sensitive and selective optical membrane for determination of Hg2+ and Pb2+ was prepared by covalent immobilization of dithizone on agarose membrane. In addition to its high stability, reproducibility and relatively long lifetime, the proposed optical sensor revealed good selectivity for target ions over a large number of alkali, alkaline earth, transition, and heavy metal ions. The proposed optical membrane displays linear responses from 1.1 × 10-8 to 2.0 × 10-6 mol L-1 and 1.2 × 10-8 to 2.4 × 10-6 mol L-1 for Hg2+ and Pb2+, respectively. The limits of detection (LOD) were 2.0 × 10-9 mol L-1 and 4.0 × 10-9 mol L-1 for Hg2+ and Pb2, respectively. The prepared optical membrane was successfully applied to the determination of Hg2+ and Pb2+ in industrial wastes, spiked tap water and natural waters without any preconcentration step.

  12. The use of a polymer inclusion membrane in a paper-based sensor for the selective determination of Cu(II).

    Science.gov (United States)

    Jayawardane, B Manori; Coo, Lilibeth dlC; Cattrall, Robert W; Kolev, Spas D

    2013-11-25

    A disposable paper-based sensor (PBS) is described for the determination of Cu(II) in natural and waste waters at approximately 2 cents per measurement. The device makes use of a polymer inclusion membrane (PIM) to provide the selectivity for Cu(II). The PIM consists of 40 wt% di(2-ethlyhexyl) phosphoric acid (D2EHPA) as the carrier, 10 wt% dioctyl phthalate (DOP) as a plasticizer, 49.5 wt% poly(vinyl chloride) (PVC) as the base polymer and 0.5 wt% (mm(-1)) 1-(2'-pyridylazo)-2-naphthol (PAN) as the colourimetric reagent. High selectivity under mildly acidic conditions (HCl, pH 2.0) is achieved for Cu(II) in the presence of frequently encountered metal ions in natural and waste waters such as Fe(III), Al(III), Zn(II), Cd(II), Pb(II), Ca(II), Mg(II), and Ni(II). The laminated PBS consists of a PIM sensing disc (2mm in diameter) attached to the centre of a circular hydrophilic zone (7 mm in diameter) pretreated with 0.01 M HCl. This hydrophilic zone separates the sample port (a circular hole in the plastic cover) from the PIM sensing disc. After introducing 19.2 μL of a sample/standard solution to the sample port, Cu(II) diffuses across the hydrophilic zone and is extracted into the PIM disc as the Cu(II)-D2EHPA complex which subsequently reacts with PAN to produce the red-purple coloured Cu(II)-PAN complex. The colour intensity of the PIM disc is measured 15 min after sample/standard introduction by scanning using a flatbed scanner. Under optimal conditions the device is characterized by a limit of detection (LOD) and limit of quantitation (LOQ) of 0.06 and 0.21 mg L(-1) Cu(II), respectively, with two linear ranges together covering the Cu(II) concentration range from 0.1 to 30.0 mg L(-1). The PBS was successfully applied to the determination of Cu(II) in hot tap water and mine tailings water. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Flexible Strain Sensor Based on Layer-by-Layer Self-Assembled Graphene/Polymer Nanocomposite Membrane and Its Sensing Properties

    Science.gov (United States)

    Zhang, Dongzhi; Jiang, Chuanxing; Tong, Jun; Zong, Xiaoqi; Hu, Wei

    2018-01-01

    Graphene is a potential building block for next generation electronic devices including field-effect transistors, chemical sensors, and radio frequency switches. Investigations of strain application of graphene-based films have emerged in recent years, but the challenges in synthesis and processing achieving control over its fabrication constitute the main obstacles towards device applications. This work presents an alternative approach, layer-by-layer self-assembly, allowing a controllable fabrication of graphene/polymer film strain sensor on flexible substrates of polyimide with interdigital electrodes. Carboxylated graphene and poly (diallyldimethylammonium chloride) (PDDA) were exploited to form hierarchical nanostructure due to electrostatic action. The morphology and structure of the film were inspected by using scanning electron microscopy, x-ray diffraction and Fourier transform infrared spectroscopy. The strain-sensing properties of the graphene/PDDA film sensor were investigated through tuning micrometer caliper exertion and a PC-assisted piezoresistive measurement system. Experimental result shows that the sensor exhibited not only excellent response and reversibility behavior as a function of deflection, but also good repeatability and acceptable linearity. The strain-sensing mechanism of the proposed sensor was attributed to the electrical resistance change resulted from piezoresistive effect.

  14. Flexible Strain Sensor Based on Layer-by-Layer Self-Assembled Graphene/Polymer Nanocomposite Membrane and Its Sensing Properties

    Science.gov (United States)

    Zhang, Dongzhi; Jiang, Chuanxing; Tong, Jun; Zong, Xiaoqi; Hu, Wei

    2018-04-01

    Graphene is a potential building block for next generation electronic devices including field-effect transistors, chemical sensors, and radio frequency switches. Investigations of strain application of graphene-based films have emerged in recent years, but the challenges in synthesis and processing achieving control over its fabrication constitute the main obstacles towards device applications. This work presents an alternative approach, layer-by-layer self-assembly, allowing a controllable fabrication of graphene/polymer film strain sensor on flexible substrates of polyimide with interdigital electrodes. Carboxylated graphene and poly (diallyldimethylammonium chloride) (PDDA) were exploited to form hierarchical nanostructure due to electrostatic action. The morphology and structure of the film were inspected by using scanning electron microscopy, x-ray diffraction and Fourier transform infrared spectroscopy. The strain-sensing properties of the graphene/PDDA film sensor were investigated through tuning micrometer caliper exertion and a PC-assisted piezoresistive measurement system. Experimental result shows that the sensor exhibited not only excellent response and reversibility behavior as a function of deflection, but also good repeatability and acceptable linearity. The strain-sensing mechanism of the proposed sensor was attributed to the electrical resistance change resulted from piezoresistive effect.

  15. The fabrication of potentiometric membrane sensors and their ...

    African Journals Online (AJOL)

    Ionophore-incorporated PVC-membrane sensors are well-established analytical tools routinely used for the selective and direct measurement of a wide variety of different ions in complex biological and environmental samples. The key ingredient of such plasticized PVC-members is the involved ionophore, defining the ...

  16. Fabrication and Characterisation of Membrane-Based Gold Electrodes

    DEFF Research Database (Denmark)

    Bakmand, Tanya; Kwasny, Dorota; Dimaki, Maria

    2015-01-01

    This work presents a versatile, membrane based electrochemical sensor with thin film electrodes fabricated through Ebeam evaporation directly on porous materials (membranes). Here, the fabrication of the electrodes is described along with possible methods for integration in fluidic systems and ch...

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

    Directory of Open Access Journals (Sweden)

    Huan Liu

    2017-10-01

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

  18. Detecting Levels of Polyquaternium-10 (PQ-10) via Potentiometric Titration with Dextran Sulphate and Monitoring the Equivalence Point with a Polymeric Membrane-Based Polyion Sensor

    OpenAIRE

    Ferguson, Stephen A.; Wang, Xuewei; Meyerhoff, Mark E.

    2016-01-01

    Polymeric quaternary ammonium salts (polyquaterniums) have found increasing use in industrial and cosmetic applications in recent years. More specifically, polyquaternium-10 (PQ-10) is routinely used in cosmetic applications as a conditioner in personal care product formulations. Herein, we demonstrate the use of potentiometric polyion-sensitive polymeric membrane-based electrodes to quantify PQ-10 levels. Mixtures containing both PQ-10 and sodium lauryl sulfate (SLS) are used as model sample...

  19. Immobilization of tris(2 pyridyl methylamine in a PVC-Membrane Sensor and Characterization of the Membrane Properties

    Directory of Open Access Journals (Sweden)

    Rezayi Majid

    2012-05-01

    Full Text Available Abstract Background Due to the increasing industrial use of titanium compounds, its determination is the subject of considerable efforts. The ionophore or membrane active recognition is the most important component of any polymeric membrane sensor. The sensor’s response depends on the ionophore and bonding between the ionophore and the target ion. Ionophores with molecule-sized dimensions containing cavities or semi-cavities can surround the target ion. The bond between the ionophore and target ion gives different selectivity and sensitivity toward the other ions. Therefore, ionophores with different binding strengths can be used in the sensor. Results In the present work, poly (vinyl chloride (PVC based membrane incorporating tris (2 pyridyl methylamine (tpm as an ionophore has been prepared and explored as a titanium(III selective sensor. Conclusions The strengths of the ion–ionophore (Ti(OH2+-tpm interactions and the role of ionophore on membrane were tested by various techniques such as elemental analysis, UV–vis, Fourier transform infrared (FTIR spectroscopy, scanning electron microscopy (SEM, and powder X-ray diffraction (XRD. All data approved the successful incorporation of organic group via covalent bond.

  20. An Umeclidinium membrane sensor; Two-step optimization strategy for improved responses.

    Science.gov (United States)

    Yehia, Ali M; Monir, Hany H

    2017-09-01

    In the scientific context of membrane sensors and improved experimentation, we devised an experimentally designed protocol for sensor optimization. Two-step strategy was implemented for Umeclidinium bromide (UMEC) analysis which is a novel quinuclidine-based muscarinic antagonist used for maintenance treatment of symptoms accompanied with chronic obstructive pulmonary disease. In the first place, membrane components were screened for ideal ion exchanger, ionophore and plasticizer using three categorical factors at three levels in Taguchi design. Secondly, experimentally designed optimization was followed in order to tune the sensor up for finest responses. Twelve experiments were randomly carried out in a continuous factor design. Nernstian response, detection limit and selectivity were assigned as responses in these designs. The optimized membrane sensor contained tetrakis-[3,5-bis(trifluoro- methyl)phenyl] borate (0.44wt%) and calix[6]arene (0.43wt%) in 50.00% PVC plasticized with 49.13wt% 2-ni-tro-phenyl octylether. This sensor, along with an optimum concentration of inner filling solution (2×10 -4 molL -1 UMEC) and 2h of soaking time, attained the design objectives. Nernstian response approached 59.7mV/decade and detection limit decreased by about two order of magnitude (8×10 -8 mol L -1 ) through this optimization protocol. The proposed sensor was validated for UMEC determination in its linear range (3.16×10 -7 -1×10 -3 mol L -1 ) and challenged for selective discrimination of other congeners and inorganic cations. Results of INCRUSE ELLIPTA ® inhalation powder analyses obtained from the proposed sensor and manufacturer's UPLC were statistically compared. Moreover the proposed sensor was successfully used for the determination of UMEC in plasma samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. CsPbBr3 Perovskite Quantum Dots-Based Monolithic Electrospun Fiber Membrane as an Ultrastable and Ultrasensitive Fluorescent Sensor in Aqueous Medium.

    Science.gov (United States)

    Wang, Yuanwei; Zhu, Yihua; Huang, Jianfei; Cai, Jin; Zhu, Jingrun; Yang, Xiaoling; Shen, Jianhua; Jiang, Hao; Li, Chunzhong

    2016-11-03

    Perovskite quantum dots with excellent optical properties and robust durability stand as an appealing and desirable candidate for fluorescence resonance energy transfer (FRET) based fluorescence detection, a powerful technique featuring excellent accuracy and convenience. In this work, a monolithic superhydrophobic polystyrene fiber membrane with CsPbBr 3 perovskite quantum dots encapsulated within (CPBQDs/PS FM) was prepared via one-step electrospinning. Coupling CPBQDs with PS matrix, this CPBQDs/PS FM composite exhibits high quantum yields (∼91%), narrow half-peak width (∼16 nm), nearly 100% fluorescence retention after being exposed to water for 10 days and 79.80% fluorescence retention after 365 nm UV-light (1 mW/cm 2 ) illumination for 60 h. Thanks to the outstanding optical property of CPBQDs, an ultralow detection limit of 0.01 ppm was obtained for Rhodamine 6G (R6G) detection, with the FRET efficiency calculated to be 18.80% in 1 ppm R6G aqueous solution. Electrospun as well-designed fiber membranes, CPBQDs/PS FM composite also possesses good tailorability and recyclability, showing exciting potential for future implementation into practical applications.

  2. Fabrication and characterization of magnetic composite membrane pressure sensor

    KAUST Repository

    Khan, Mohammed Asadullah

    2016-04-20

    This paper describes a magnetic field powered pressure sensor, which comprises a coil array and a magnetic composite membrane. The composite membrane is made by embedding a ribbon of the amorphous soft magnetic alloy Vitrovac®, in a 17 mm x 25 mm x 1.5 mm Polydimethylsiloxane (PDMS) layer. PDMS is chosen for its low Young\\'s modulus and the amorphous alloy for its high permeability. The membrane is suspended 1.5 mm above a 17x19 array of microfabricated planar coils. The coils are fabricated by patterning a 620 nm thick gold layer. Each coil occupies an area of 36000 μm2 and consists of 14 turns. The sensor is tested by subjecting it to pressure and simultaneously exciting it by a 24 A/m, 100 kHz magnetic field. A pressure change from 0 kPa to 5.1 kPa, results in a 5400 ppm change in the voltage output.

  3. An articulated predictive model for fluid-free artificial basilar membrane as broadband frequency sensor

    Science.gov (United States)

    Ahmed, Riaz; Banerjee, Sourav

    2018-02-01

    In this article, an extremely versatile predictive model for a newly developed Basilar meta-Membrane (BM2) sensors is reported with variable engineering parameters that contribute to it's frequency selection capabilities. The predictive model reported herein is for advancement over existing method by incorporating versatile and nonhomogeneous (e.g. functionally graded) model parameters that could not only exploit the possibilities of creating complex combinations of broadband frequency sensors but also explain the unique unexplained physical phenomenon that prevails in BM2, e.g. tailgating waves. In recent years, few notable attempts were made to fabricate the artificial basilar membrane, mimicking the mechanics of the human cochlea within a very short range of frequencies. To explain the operation of these sensors a few models were proposed. But, we fundamentally argue the "fabrication to explanation" approach and proposed the model driven predictive design process for the design any (BM2) as broadband sensors. Inspired by the physics of basilar membrane, frequency domain predictive model is proposed where both the material and geometrical parameters can be arbitrarily varied. Broadband frequency is applicable in many fields of science, engineering and technology, such as, sensors for chemical, biological and acoustic applications. With the proposed model, which is three times faster than its FEM counterpart, it is possible to alter the attributes of the selected length of the designed sensor using complex combinations of model parameters, based on target frequency applications. Finally, the tailgating wave peaks in the artificial basilar membranes that prevails in the previously reported experimental studies are also explained using the proposed model.

  4. A Schiff base complex of Zn(II) as a neutral carrier for highly selective PVC membrane sensors for the sulfate ion.

    Science.gov (United States)

    Shamsipur, M; Yousefi, M; Hosseini, M; Ganjali, M R; Sharghi, H; Naeimi, H

    2001-07-01

    Novel polymeric membrane (PME) and coated graphite (CGE) sulfate-selective electrodes based on a recently synthesized Schiff base complex of Zn(II) were prepared. The electrodes reveal a Nernstian behavior over wide SO4(2-) ion concentration ranges (5.0 x 10(-5)-1.0 x 10(-1) M for PME and 1.0 x 10(-7)-1.0 x 10(-1) M for CGE) and very low detection limits (2.8 x 10(-5) M for PME and 8.5 x 10(-8) M for CGE). The potentiometric response is independent of the pH of the solution in the pH range 3.0-7.0. The electrodes manifest advantages of low resistance, very fast response, and, most importantly, good selectivities relative to a wide variety of other anions. In fact, the selectivity behavior of the proposed SO4(2) ion-selective electrodes shows a great improvement compared to the previously reported electrodes for sulfate ion. The electrodes can be used for at least 3 months without any appreciable divergence in potentials. The electrodes were used as an indicator electrode in the potentiometric titration of sulfate and barium ions and in the determination of iron in ferrous sulfate tablets.

  5. Novel PVC-membrane potentiometric sensors based on a recently synthesized sulfur-containing macrocyclic diamide for Cd2+ ion. Application to flow-injection potentiometry.

    Science.gov (United States)

    Shamsipur, Mojtaba; Dezaki, Abbas Shirmardi; Akhond, Morteza; Sharghi, Hashem; Paziraee, Zahra; Alizadeh, Kamal

    2009-12-30

    A new sulfur-containing macrocyclic diamide, 1,15-diaza-3,4,12,13-dibenzo-5,11-dithia-8-oxa-1,15-(2,6-pyrido)cyclooctadecan-2,14-dione, L, was synthesized, characterized and used as an active component for fabrication of PVC-based polymeric membrane (PME), coated graphite (CGE) and coated silver wire electrodes (CWE) for sensing Cd(2+) ion. The electrodes exhibited linear Nernstian responses to Cd(2+) ion in the concentration range of 3.3 x 10(-6) to 3.3 x 10(-1)M (for PME, LOD=1.2 x 10(-6)M), 2.0 x 10(-7) to 3.3 x 10(-1)M (for CWE, LOD=1.3 x 10(-7)M) and 1.6 x 10(-8) to 1.3 x 10(-1)M (for CGE, LOD=1.0 x 10(-8)M). The CGE was used as a proper detection system in flow-injection potentiometry (FIP) with a linear Nernstian range of 3.2 x 10(-8) to 1.4 x 10(-1)M (LOD=1.3 x 10(-8)M). The optimum pH range was 3.5-7.6. The electrodes revealed fairly good discriminating ability towards Cd(2+) in comparison with a large number of alkali, alkaline earth, transition and heavy metal ions. The electrodes found to be chemically inert, showing a fast response time of <5s, and could be used practically over a period of about 2-3 months. The practical utility of the proposed system has also been reported.

  6. Smell identification of spices using nanomechanical membrane-type surface stress sensors

    Science.gov (United States)

    Imamura, Gaku; Shiba, Kota; Yoshikawa, Genki

    2016-11-01

    Artificial olfaction, that is, a chemical sensor system that identifies samples by smell, has not been fully achieved because of the complex perceptional mechanism of olfaction. To realize an artificial olfactory system, not only an array of chemical sensors but also a valid feature extraction method is required. In this study, we achieved the identification of spices by smell using nanomechanical membrane-type surface stress sensors (MSS). Features were extracted from the sensing signals obtained from four MSS coated with different types of polymers, focusing on the chemical interactions between polymers and odor molecules. The principal component analysis (PCA) of the dataset consisting of the extracted parameters demonstrated the separation of each spice on the scatter plot. We discuss the strategy for improving odor identification based on the relationship between the results of PCA and the chemical species in the odors.

  7. Porphyrin-functionalized porous polysulfone membrane towards an optical sensor membrane for sorption and detection of cadmium(II)

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Lizhi, E-mail: zhaolizhi_phd@163.com [State Key Laboratory of Separation Membranes and Membrane Processes, School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin 300387 (China); Li, Min; Liu, Manman; Zhang, Yuecong [State Key Laboratory of Separation Membranes and Membrane Processes, School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin 300387 (China); Wu, Chenglin [School of Pharmaceutical and Chemical Engineering, Taizhou University, Taizhou 317000, Zhejiang Province (China); Zhang, Yuzhong, E-mail: zhangyz2004cn@163.com [State Key Laboratory of Separation Membranes and Membrane Processes, School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin 300387 (China)

    2016-01-15

    Highlights: • An optical sensor membrane is prepared by TMPyP and PNaSS-grafted PSF membrane. • The optical sensor membrane shows enhanced sorption for cadmium(II). • Visual and spectrophotometric detection can be achieved. • The functional membrane exhibits good stability and reusability. - Abstract: In this study, an optical sensor membrane was prepared for sorption and detection of cadmium(II) (Cd(II)) in aqueous solution. A polyanion, poly(sodium 4-styrenesulfonate) (PNaSS), was grafted onto the chloromethylated polysulfone (CMPSF) microporous membrane via surface-initiated ATRP. 5,10,15,20-tetrakis(4-N-methylpyridyl) porphyrin p-toluenesulfonate (TMPyP) was immobilized onto the PNaSS-grafted polysulfone (PSF-PNaSS) membrane through electrostatic interaction. The TMPyP-functionalized membrane exhibited an enhanced sorption for, and distinct color and spectral response to cadmium(II) (Cd(II)) in aqueous solution. Larger immobilization capacity of TMPyP on the membrane led to stronger sorption for Cd(II), and smaller one made the optical sensor have a faster (in minutes) and more sensitive response to the ion. The detection limit study indicated that the functional membrane with proper amount of TMPyP (<0.5 mg/g) could still have color and spectral response to Cd(II) solutions at an extreme low concentration (10{sup −4} mg/L). The optical sensor membrane exhibited good stability and reusability which made it efficient for various sorptive removal and detection applications.

  8. Optical Fiber Grating based Sensors

    DEFF Research Database (Denmark)

    Michelsen, Susanne

    2003-01-01

    In this thesis differenct optical fiber gratings are used for sensor purposes. If a fiber with a core concentricity error (CCE) is used, a directional dependent bend sensor can be produced. The CCE direction can be determined by means of diffraction. This makes it possible to produce long......-period gratings in a fiber with a CCE direction parallel or perpendicular to the writing direction. The maximal bending sensitivity is independent on the writing direction, but the detailed bending response is different in the two cases. A temperature and strain sensor, based on a long-period grating and two...... wavelength. It is shown that it is possible to tune and modulate a DFB fiber laser with both strain from a piezoelectric transducer and by temperature through resistive heating of a methal film. Both a chemical deposited silver layer and an electron-beam evaporation technique has been investigated, to find...

  9. Radar based autonomous sensor module

    Science.gov (United States)

    Styles, Tim

    2016-10-01

    Most surveillance systems combine camera sensors with other detection sensors that trigger an alert to a human operator when an object is detected. The detection sensors typically require careful installation and configuration for each application and there is a significant burden on the operator to react to each alert by viewing camera video feeds. A demonstration system known as Sensing for Asset Protection with Integrated Electronic Networked Technology (SAPIENT) has been developed to address these issues using Autonomous Sensor Modules (ASM) and a central High Level Decision Making Module (HLDMM) that can fuse the detections from multiple sensors. This paper describes the 24 GHz radar based ASM, which provides an all-weather, low power and license exempt solution to the problem of wide area surveillance. The radar module autonomously configures itself in response to tasks provided by the HLDMM, steering the transmit beam and setting range resolution and power levels for optimum performance. The results show the detection and classification performance for pedestrians and vehicles in an area of interest, which can be modified by the HLDMM without physical adjustment. The module uses range-Doppler processing for reliable detection of moving objects and combines Radar Cross Section and micro-Doppler characteristics for object classification. Objects are classified as pedestrian or vehicle, with vehicle sub classes based on size. Detections are reported only if the object is detected in a task coverage area and it is classified as an object of interest. The system was shown in a perimeter protection scenario using multiple radar ASMs, laser scanners, thermal cameras and visible band cameras. This combination of sensors enabled the HLDMM to generate reliable alerts with improved discrimination of objects and behaviours of interest.

  10. A highly sensitive and selective sensor based on a graphene-coated carbon paste electrode modified with a computationally designed boron-embedded duplex molecularly imprinted hybrid membrane for the sensing of lamotrigine.

    Science.gov (United States)

    Wang, Hongjuan; Qian, Duo; Xiao, Xilin; Gao, Shuqin; Cheng, Jianlin; He, Bo; Liao, Lifu; Deng, Jian

    2017-08-15

    An innovative electrochemical sensor, based on a carbon paste electrode (CPE) modified with graphene (GR) and a boron-embedded duplex molecularly imprinted hybrid membrane (B-DMIHM), was fabricated for the highly sensitive and selective determination of lamotrigine (LMT). Density functional theory (DFT) was employed to study the interactions between the template and monomers to screen appropriate functional monomers for rational design of the B-DMIHM. The distinct synergic effect of GR and B-DMIHM was evidenced by the positive shift of the reduction peak potential of LMT at B-DMIHM/GR modified CPE (B-DMIHM/GR/CPE) by about 300mV, and the 13-fold amplification of the peak current, compared to a bare carbon paste electrode (CPE). The electrochemical reduction mechanism of lamotrigine was investigated by different voltammetric techniques. It was illustrated that square wave voltammetry (SWV) was more sensitive than different pulse voltammetry (DPV) for the quantitative analysis of LMT. Thereafter, a highly sensitive electroanalytical method for LMT was established by SWV at B-DMIHM/GR/CPE with a good linear relationship from 5.0×10 -8 to 5.0×10 -5 and 5.0×10 -5 to 3.0×10 -4 molL -1 with a lower detection limit (1.52×10 -9 molL -1 ) based on the lower linear range(S/N=3). The practical application of the sensor was demonstrated by determining the concentration of LMT in pharmaceutical and biological samples with good precision (RSD 1.04-4.41%) and acceptable recoveries (92.40-107.0%). Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Application of the Sensor Selection Approach in Polymer Electrolyte Membrane Fuel Cell Prognostics and Health Management

    Directory of Open Access Journals (Sweden)

    Lei Mao

    2017-09-01

    Full Text Available In this paper, the sensor selection approach is investigated with the aim of using fewer sensors to provide reliable fuel cell diagnostic and prognostic results. The sensitivity of sensors is firstly calculated with a developed fuel cell model. With sensor sensitivities to different fuel cell failure modes, the available sensors can be ranked. A sensor selection algorithm is used in the analysis, which considers both sensor sensitivity to fuel cell performance and resistance to noise. The performance of the selected sensors in polymer electrolyte membrane (PEM fuel cell prognostics is also evaluated with an adaptive neuro-fuzzy inference system (ANFIS, and results show that the fuel cell voltage can be predicted with good quality using the selected sensors. Furthermore, a fuel cell test is performed to investigate the effectiveness of selected sensors in fuel cell fault diagnosis. From the results, different fuel cell states can be distinguished with good quality using the selected sensors.

  12. Chitosan-based ferrimagnetic membrane

    International Nuclear Information System (INIS)

    Macedo, M.A.; Silva, M.N.B.; Cestari, A.R.; Vieira, E.F.S.; Sasaki, J.M.; Goes, J.C.; Aguiar, J. Albino

    2004-01-01

    A chitosan-based ferrimagnetic membrane (Chitosan/NiFe 2 O 4 ) was prepared and it showed a typical magnetization of soft ferrimagnetic material with M s =16 emu/g at 50 kOe and a high capacity to extract Hg(II), Cu(II) and Zn(II) ions from aqueous solutions. These results indicate that the Chitosan/NiFe 2 O 4 is a good candidate to remove heavy metals from polluted water with the possibility that its recovery can be done by an electromagnet

  13. Reputation-based secure sensor localization in wireless sensor networks.

    Science.gov (United States)

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

    2014-01-01

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

  14. Miniaturized membrane sensors for potentiometric determination of metoprolol tartrate and hydrochlorothiazide.

    Science.gov (United States)

    Ramadan, Nesrin K; Mohamed, Heba M; Mostafa, Azza A

    2012-06-01

    Four microsized graphite and platinum wire poly(vinyl chloride) matrix membrane electrodes responsive to some drugs affecting cardiovascular system, Metoprolol tartrate (MT) and Hydrochlorothiazide (HZ) were developed, described and characterized. These sensors were constructed by using (2-Hydroxypropyl)-β-cyclodextrin (2HP β-CD) as an ionophore which has a significant influence on increasing both membrane sensitivity and selectivity. The four sensors were fabricated in a polymeric matrix of carboxylated polyvinyl chloride (PVC-COOH) and dioctylphthalate (DOP) as a plasticizer, based on the interaction between the drugs and the dissociated COOH groups in the PVC-COOH. Fast and stable Nernstian responses of 1.0 × 10-6-1.0 × 10-2 M for MT (sensors 1 and 2) and of 1.0 × 10-7-1.0 × 10-3 M for HZ (sensors 3 and 4) over pH range 3.0-9.0 and 3.0-7.0 for the MT and HZ sensors respectively were obtained. Nernstian slopes of 56.2, 54.6, 19.0 and 20.8 mV/decade for electrodes 1-4 respectively were observed. The proposed method displayed useful analytical characteristics for the determination of MT and HZ in their pure powder forms with average recoveries of 99.11 ± 0.357, 99.21 ± 0.389, 100.08 ± 0.459 and 100.28 ± 0.438% for sensors 1-4 respectively. The lower limit of detection (LOD) were 5.5 × 10-6, 4.5 × 10-6, 4.8 × 10-8 and 5.0 × 10-8 M for sensors 1-4 respectively indicated high sensitivity. The four sensors displayed a good stability over a period of 6 weeks. The selectivity coefficients of the developed sensors indicated excellent selectivity. Results obtained by the four electrodes revealed the performance characteristics of these electrodes which evaluated according to IUPAC recommendations. The method was successively applied for the determination of MT and HZ in presence of each other, in presence of Salamide (SA), the main degradation product of HZ, in their pharmaceutical formulations and in human plasma samples. Statistical comparison between the

  15. Development of Multichannel Artificial Lipid-Polymer Membrane Sensor for Phytomedicine Application

    Science.gov (United States)

    Ahmad, Mohd Noor; Ismail, Zhari; Chew, Oon–Sim; Islam, AKM Shafiqul; Shakaff, Ali Yeon Md

    2006-01-01

    Quality control of herbal medicines remain a challenging issue towards integrating phytomedicine into the primary health care system. As medicinal plants is a complicated system of mixtures, a rapid and cost-effective evaluation method to characterize the chemical fingerprint of the plant without performing laborious sample preparation procedure is reported. A novel research methodology based on an in-house fabricated multichannel sensor incorporating an array of artificial lipid-polymer membrane as a fingerprinting device for quality evaluation of a highly sought after herbal medicine in the Asean Region namely Eurycoma longifolia (Tongkat Ali). The sensor array is based on the principle of the bioelectronic tongue that mimics the human gustatory system through the incorporation of artificial lipid material as sensing element. The eight non-specific sensors have partially overlapping selectivity and cross-sensitivity towards the targeted analyte. Hence, electrical potential response represented by radar plot is used to characterize extracts from different parts of plant, age, batch-to-batch variation and mode of extraction of E. longifolia through the obtained potentiometric fingerprint profile. Classification model was also developed classifying various E. longifolia extracts with the aid of chemometric pattern recognition tools namely hierarchical cluster analysis (HCA) and principal component analysis (PCA). The sensor seems to be a promising analytical device for quality control based on potentiometric fingerprint analysis of phytomedicine.

  16. Amperometric S-Nitrosothiol Sensor with Enhanced Sensitivity Based on Organoselenium Catalysts

    OpenAIRE

    Cha, Wansik; Anderson, Meredith R.; Zhang, Fenghua; Meyerhoff, Mark E.

    2008-01-01

    A new S-nitrosothiol (RSNO) detection strategy based on an electrochemical sensor is described for rapidly estimating levels of total RSNOs in blood and other biological samples. The sensor employs a cellulose dialysis membrane covalently modified with an organoselenium catalyst that converts RSNOs to NO at the distal tip of an amperometric NO sensor. The sensor is characterized by very low detection limits (< 20 nM), good long-term stability and can be employed for the rapid detection of tot...

  17. Carbon Nanotube-Based Chemiresistive Sensors.

    Science.gov (United States)

    Tang, Ruixian; Shi, Yongji; Hou, Zhongyu; Wei, Liangming

    2017-04-18

    The development of simple and low-cost chemical sensors is critically important for improving human life. Many types of chemical sensors have been developed. Among them, the chemiresistive sensors receive particular attention because of their simple structure, the ease of high precise measurement and the low cost. This review mainly focuses on carbon nanotube (CNT)-based chemiresistive sensors. We first describe the properties of CNTs and the structure of CNT chemiresistive sensors. Next, the sensing mechanism and the performance parameters of the sensors are discussed. Then, we detail the status of the CNT chemiresistive sensors for detection of different analytes. Lastly, we put forward the remaining challenges for CNT chemiresistive sensors and outlook the possible opportunity for CNT chemiresistive sensors in the future.

  18. Robust High Performance Aquaporin based Biomimetic Membranes

    DEFF Research Database (Denmark)

    Helix Nielsen, Claus; Zhao, Yichun; Qiu, C.

    2013-01-01

    Aquaporins are water channel proteins with high water permeability and solute rejection, which makes them promising for preparing high-performance biomimetic membranes. Despite the growing interest in aquaporin-based biomimetic membranes (ABMs), it is challenging to produce robust and defect...... on top of a support membrane. Control membranes, either without aquaporins or with the inactive AqpZ R189A mutant aquaporin served as controls. The separation performance of the membranes was evaluated by cross-flow forward osmosis (FO) and reverse osmosis (RO) tests. In RO the ABM achieved a water...... permeability of ~ 4 L/(m2 h bar) with a NaCl rejection > 97% at an applied hydraulic pressure of 5 bar. The water permeability was ~40% higher compared to a commercial brackish water RO membrane (BW30) and an order of magnitude higher compared to a seawater RO membrane (SW30HR). In FO, the ABMs had > 90...

  19. Bulk disk resonator based ultrasensitive mass sensor

    DEFF Research Database (Denmark)

    Cagliani, Alberto; Davis, Zachary James

    2009-01-01

    In the framework of developing an innovative label-free sensor for multiarrayed biodetection applications, we present a novel bulk resonator based mass sensor. The sensor is a polysilicon disk which shows a Q-factor of 6400 in air at 68.8 MHz, resulting in mass resolutions down in the femtogram r...

  20. Wireless SAW Based Temperature Gradient Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Prime Photonics proposes design and development of a surface acoustic wave (SAW) based temperature gradient sensor for instrumentation of thermal protection systems...

  1. Design of an optical thermal sensor for proton exchange membrane fuel cell temperature measurement using phosphor thermometry

    Science.gov (United States)

    Inman, Kristopher; Wang, Xia; Sangeorzan, Brian

    Internal temperatures in a proton exchange membrane (PEM) fuel cell govern the ionic conductivities of the polymer electrolyte, influence the reaction rate at the electrodes, and control the water vapor pressure inside the cell. It is vital to fully understand thermal behavior in a PEM fuel cell if performance and durability are to be optimized. The objective of this research was to design, construct, and implement thermal sensors based on the principles of the lifetime-decay method of phosphor thermometry to measure temperatures inside a PEM fuel cell. Five sensors were designed and calibrated with a maximum uncertainty of ±0.6 °C. Using these sensors, surface temperatures were measured on the cathode gas diffusion layer of a 25 cm 2 PEM fuel cell. The test results demonstrate the utility of the optical temperature sensor design and provide insight into the thermal behavior found in a PEM fuel cell.

  2. Microfluidic devices for investigation of biomimetic membranes for sensor and separation applications

    DEFF Research Database (Denmark)

    Pszon-Bartosz, Kamila Justyna

    The term biomimetic membrane denotes membrane that mimics biological cell membrane. Artificially made membranes are powerful tools for the fundamental biophysical studies of membrane proteins. Moreover, they may be used in biomedicine, serving as biosensors in high-throughput screening of potential...... drug candidates and in separation technologies, where an exciting example is water purification device based on biomimetic membranes containing aquaporins (highly water selective proteins). However, there are many challenges that must be overcome in order to build biomimetic membrane-based devices...... for industrial applications. Among them are the inherent fragility of lipid membranes, the challenge of up-scaling the effective membrane area and the quantification of the protein delivery to the lipid membrane which may determined the biomimetic membrane application. This PhD thesis addresses the above...

  3. Relationship between the Amount of Bitter Substances Adsorbed onto Lipid/Polymer Membrane and the Electric Response of Taste Sensors

    Directory of Open Access Journals (Sweden)

    Kiyoshi Toko

    2014-09-01

    Full Text Available The bitterness of bitter substances can be measured by the change in the membrane electric potential caused by adsorption (CPA using a taste sensor (electronic tongue. In this study, we examined the relationship between the CPA value due to an acidic bitter substance and the amount of the bitter substance adsorbed onto lipid/polymer membranes, which contain different lipid contents, used in the taste sensor. We used iso-α-acid which is an acidic bitter substance found in several foods and beverages. The amount of adsorbed iso-α-acid, which was determined by spectroscopy, showed a maximum at the lipid concentration 0.1 wt % of the membrane, and the same phenomenon was observed for the CPA value. At the higher lipid concentration, however, the amount adsorbed decreased and then remained constant, while the CPA value decreased monotonically to zero. This constant adsorption amount was observed when the membrane potential in the reference solution did not change with increasing lipid concentration. The decrease in CPA value in spite of the constant adsorption amount is caused by a decrease in the sensitivity of the membrane as the surface charge density increases. The reason why the peaks appeared in both the CPA value and adsorption amount is based on the contradictory adsorption properties of iso-α-acid. The increasing charged lipid concentration of the membrane causes an increasing electrostatic attractive interaction between iso-α-acid and the membrane, but simultaneously causes a decreasing hydrophobic interaction that results in decreasing adsorption of iso-α-acid, which also has hydrophobic properties, onto the membrane. Estimates of the amount of adsorption suggest that iso-α-acid molecules are adsorbed onto both the surface and interior of the membrane.

  4. Relational-Based Sensor Data Cleansing

    DEFF Research Database (Denmark)

    Iftikhar, Nadeem; Liu, Xiufeng; Nordbjerg, Finn Ebertsen

    2015-01-01

    Today sensors are widely used in many monitoring applications. Due to some random environmental effects and/or sensing failures, the collected sensor data is typically noisy. Thus, it is critical to cleanse the sensor data before using it to answer queries or conduct data analysis. Popular data...... cleansing approaches, such as classification, prediction and moving average are not suited for embedded sensor devices, due to the limited storage and processing capabilities. In this paper, we propose a sensor data cleansing approach using the relational-based technologies, including constraints, triggers...

  5. Method of detecting defects in ion exchange membranes of electrochemical cells by chemochromic sensors

    Science.gov (United States)

    Brooker, Robert Paul; Mohajeri, Nahid

    2016-01-05

    A method of detecting defects in membranes such as ion exchange membranes of electrochemical cells. The electrochemical cell includes an assembly having an anode side and a cathode side with the ion exchange membrane in between. In a configuration step a chemochromic sensor is placed above the cathode and flow isolation hardware lateral to the ion exchange membrane which prevents a flow of hydrogen (H.sub.2) between the cathode and anode side. The anode side is exposed to a first reactant fluid including hydrogen. The chemochromic sensor is examined after the exposing for a color change. A color change evidences the ion exchange membrane has at least one defect that permits H.sub.2 transmission therethrough.

  6. Chemo-spectroscopic sensor for carboxyl terminus overexpressed in carcinoma cell membrane.

    Science.gov (United States)

    Stanca, Sarmiza E; Matthäus, Christian; Neugebauer, Ute; Nietzsche, Sandor; Fritzsche, Wolfgang; Dellith, Jan; Heintzmann, Rainer; Weber, Karina; Deckert, Volker; Krafft, Christoph; Popp, Jürgen

    2015-10-01

    Certain carboxyl groups of the plasma membrane are involved in tumorgenesis processes. A gold core-hydroxyapatite shell (AuHA) nanocomposite is introduced as chemo-spectroscopic sensor to monitor these carboxyl groups of the cell membrane. Hydroxyapatite (HA) plays the role both of a chemical detector and of a biocompatible Raman marker. The principle of detection is based on chemical interaction between the hydroxyl groups of the HA and the carboxyl terminus of the proteins. The AuHA exhibits a surface enhanced Raman scattering (SERS) signal at 954 cm(-1) which can be used for its localization. The bio-sensing capacity of AuHA towards human skin epidermoid carcinoma (A431) and Chinese hamster ovary (CHO) cell lines is investigated using Raman microspectroscopic imaging. The localization of AuHA on cells is correlated with scanning electron microscopy, transmission electron microscopy and structured illumination fluorescence microscopy. This qualitative approach is a step towards a quantitative study of the proteins terminus. This method would enable further studies on the molecular profiling of the plasma membrane, in an attempt to provide accurate cell identification. Using a gold core-hydroxyapatite shell (AuHA) nanocomposite, the authors in this paper showed the feasibility of detecting and differentiating cell surface molecules by surface enhanced Raman scattering. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Study of sweet taste evaluation using taste sensor with lipid/polymer membranes.

    Science.gov (United States)

    Habara, Masaaki; Ikezaki, Hidekazu; Toko, Kiyoshi

    2004-07-15

    The higher sensitivity for sweeteners can be achieved by newly developed lipid/polymer membranes. The membrane is composed of lipids such as phosphoric acid di-n-hexadecyl ester and tetradodecylammoniumbromid, and a plasticizer, dioctyl phenylphosphonate. As a result of changing electric charge of the membrane surface, the newly developed membrane shows 5-10 times higher sensitivity for sucrose than the conventional ones. We also applied the sensor to other sugars such as sugar alcohol which is used as alternative sweetness or food additives. The experimental results of other sweeteners relatively correspond to human sensory evaluation, though the sensitivity for some sugars need to be improved.

  8. Ceria Based Composite Membranes for Oxygen Separation

    DEFF Research Database (Denmark)

    Gurauskis, Jonas; Ovtar, Simona; Kaiser, Andreas

    2014-01-01

    Mixed ionic-electronic conducting membranes for oxygen gas separation are attracting a lot of interest due to their promising potential for the pure oxygen and the syngas production. Apart from the need for a sufficiently high oxygen permeation fluxes, the prolonged stability of these membranes...... under the large oxygen potential gradients at elevated temperatures is decisive for the future applications. The gadolinium doped cerium oxide (CGO) based composite membranes are considered as promising candidates due to inherent stability of CGO phase. The CGO matrix is a main oxygen ion transporter......; meanwhile the primary role of a secondary phase in this membrane is to compensate the low electronic conductivity of matrix at intended functioning conditions. In this work thin film (15-20 μm) composite membranes based on CGO matrix and LSF electronic conducting phase were fabricated and evaluated...

  9. Metal bridges between the PhoQ sensor domain and the membrane regulate transmembrane signaling.

    Science.gov (United States)

    Cho, Uhn Soo; Bader, Martin W; Amaya, Maria F; Daley, Margaret E; Klevit, Rachel E; Miller, Samuel I; Xu, Wenqing

    2006-03-10

    Bacterial histidine kinases respond to environmental stimuli by transducing a signal from an extracytosolic sensor domain to a cytosolic catalytic domain. Among them, PhoQ promotes bacterial virulence and is tightly repressed by the divalent cations such as calcium and magnesium. We have determined the crystal structure of the PhoQ sensor domain from Salmonella typhimurium in the Ca2+-bound state, which reveals a highly negatively charged surface that is in close proximity to the inner membrane. This acidic surface binds at least three Ca2+, which mediate the PhoQ-membrane interaction. Mutagenesis analysis indicates that structural integrity at the membrane proximal region of the PhoQ sensor domain promotes metal-mediated repression. We propose that depletion or displacement of divalent cations leads to charge repulsion between PhoQ and the membrane, which initiates transmembrane signaling through a change in orientation between the PhoQ sensor domain and membrane. Therefore, both PhoQ and the membrane are required for extracytosolic sensing and transmembrane signaling.

  10. UAV-Based Sensor Web Monitoring System

    Directory of Open Access Journals (Sweden)

    Masahiko Nagai

    2012-01-01

    Full Text Available An unmanned aerial vehicle- (UAV- based monitoring system is developed as an intermediate system between aerial survey and ground survey. All the measurement tools are mounted on the UAV to acquire detailed information from low altitudes which is different from a satellite or a plane. The monitoring is carried out from the sky, but the spatial and temporal resolutions are freely selected near the ground. In this study, the data is easily acquired with safety and mobility by the utilization of a sensor web. A sensor web is a type of sensor network which is well suited for environmental monitoring. Sensor nodes are spatially distributed and wirelessly communicate with each other. In this study, the UAV-based system is considered as a mobile sensor node. This study proposes a combination of UAV-based monitoring with a ubiquitous sensor network.

  11. Micro technology based sun sensor

    DEFF Research Database (Denmark)

    Hales, Jan Harry; Pedersen, Martin; Fléron, René

    2003-01-01

    . This fact enables students to get hands-on experience with satellite systems design and project management. This paper describes the attitude control and determination system of a Danish student satellite (DTUsat), with main focus on the two-axis MOEMS sun sensor developed. On the magnetotorquer controlled...... various payloads and platforms. The conventional and commercial actuators and attitude sensors are in most cases not suited for these satellites, which again lead to new design considerations. Another important property is the launch cost, which can be kept relatively low as a result of the concept...... DTUsat sun sensors are needed along with a magnetometer to obtain unambiguous attitude determination for the ACDS and the payloads - an electrodynamic tether and a camera. The accuracy needed was not obtainable by employing conventional attitude sensors. Hence a linear slit sensor was designed...

  12. Micro technology based sun sensor

    DEFF Research Database (Denmark)

    Hales, Jan Harry; Pedersen, Martin; Fléron, René

    2003-01-01

    various payloads and platforms. The conventional and commercial actuators and attitude sensors are in most cases not suited for these satellites, which again lead to new design considerations. Another important property is the launch cost, which can be kept relatively low as a result of the concept....... This fact enables students to get hands-on experience with satellite systems design and project management. This paper describes the attitude control and determination system of a Danish student satellite (DTUsat), with main focus on the two-axis MOEMS sun sensor developed. On the magnetotorquer controlled...... DTUsat sun sensors are needed along with a magnetometer to obtain unambiguous attitude determination for the ACDS and the payloads - an electrodynamic tether and a camera. The accuracy needed was not obtainable by employing conventional attitude sensors. Hence a linear slit sensor was designed...

  13. Silicon/Porous Silicon Composite Membrane for High Sensitivity Pressure Sensor

    Science.gov (United States)

    2009-07-21

    for integrating with other processes on silicon wafer. The fabrication of silicone rubber membranes for making microvalves has been reported [5...alcohol (IPA) is used along with HF to increase the wettability of the silicon surface and to remove the bubbles formed during the reaction. Aluminium ...Report for AOARD funded Project No. AOARD-074061 Title: Silicon /Porous Silicon composite membrane for high sensitivity pressure sensor PI

  14. Potentiometric determination of moxifloxacin in some pharmaceutical formulation using PVC membrane sensors.

    Science.gov (United States)

    Hefnawy, Mohammed M; Homoda, Atef M; Abounassif, Mohammed A; Alanazi, Amer M; Al-Majed, Abdulrahaman; Mostafa, Gamal A

    2014-01-01

    The construction and electrochemical response characteristics of Poly (vinyl chloride) membrane sensors for moxifloxacin HCl (MOX) are described. The sensing membranes incorporate ion association complexes of moxifloxacin cation and sodium tetraphenyl borate (NaTPB) (sensor 1), phosphomolybdic acid (PMA) (sensor 2) or phosphotungstic acid (PTA) (sensor 3) as electroactive materials. The sensors display a fast, stable and near-Nernstian response over a relative wide moxifloxacin concentration range (1 × 10(-2) - 4.0 × 10(-6), 1 × 10(-2) - 5.0 × 10(-6), 1 × 10(-2) - 5.0 × 10(-6) M), with detection limits of 3 × 10(-6), 4 × 10(-6) and 4.0 × 10(-6) M for sensor 1, 2 and 3, respectively over a pH range of 6.0 - 9.0. The sensors show good discrimination of moxifloxacin from several inorganic and organic compounds. The direct determination of 400 μg/ml of moxifloxacin show an average recovery of 98.5, 99.1 and 98.6% and a mean relative standard deviation of 1.8, 1.6 and 1.8% for sensors 1, 2 and 3 respectively. The proposed sensors have been applied for direct determination of moxifloxacin in some pharmaceutical preparations. The results obtained by determination of moxifloxacin in tablets using the proposed sensors are comparable favorably with those obtained using the US Pharmacopeia method. The sensors have been used as indicator electrodes for potentiometric titration of moxifloxacin.

  15. Model-Based Method for Sensor Validation

    Science.gov (United States)

    Vatan, Farrokh

    2012-01-01

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

  16. LPG based all plastic pressure sensor

    DEFF Research Database (Denmark)

    Bundalo, Ivan-Lazar; Lwin, R.; Leon-Saval, S.

    2015-01-01

    A prototype all-plastic pressure sensor is presented and characterized for potential use as an endoscope. The sensor is based on Long Period Gratings (LPG) inscribed with a CO2 laser in 6-ring microstructured PMMA fiber. Through a latex coated, plastic 3D-printed transducer pod, external pressure...

  17. Integrated Temperature Sensors based on Heat Diffusion

    NARCIS (Netherlands)

    Van Vroonhoven, C.P.L.

    2015-01-01

    This thesis describes the theory, design and implementation of a new class of integrated temperature sensors, based on heat diffusion. In such sensors, temperature is sensed by measuring the time it takes for heat to diffuse through silicon. An on-chip thermal delay can be determined by geometry and

  18. Recent Advances in Paper-Based Sensors

    Directory of Open Access Journals (Sweden)

    Edith Chow

    2012-08-01

    Full Text Available Paper-based sensors are a new alternative technology for fabricating simple, low-cost, portable and disposable analytical devices for many application areas including clinical diagnosis, food quality control and environmental monitoring. The unique properties of paper which allow passive liquid transport and compatibility with chemicals/biochemicals are the main advantages of using paper as a sensing platform. Depending on the main goal to be achieved in paper-based sensors, the fabrication methods and the analysis techniques can be tuned to fulfill the needs of the end-user. Current paper-based sensors are focused on microfluidic delivery of solution to the detection site whereas more advanced designs involve complex 3-D geometries based on the same microfluidic principles. Although paper-based sensors are very promising, they still suffer from certain limitations such as accuracy and sensitivity. However, it is anticipated that in the future, with advances in fabrication and analytical techniques, that there will be more new and innovative developments in paper-based sensors. These sensors could better meet the current objectives of a viable low-cost and portable device in addition to offering high sensitivity and selectivity, and multiple analyte discrimination. This paper is a review of recent advances in paper-based sensors and covers the following topics: existing fabrication techniques, analytical methods and application areas. Finally, the present challenges and future outlooks are discussed.

  19. PDMS membranes as sensing element in optical sensors for gas detection in water

    Directory of Open Access Journals (Sweden)

    Stefania Torino

    2017-11-01

    Full Text Available Polydimethylsiloxane (PDMS has been introduced the first time about 20years ago. This polymer is worldwide used for the rapid prototyping of microfluidic device through a replica molding process. However, the great popularity of PDMS is not only related to its easy processability, but also to its chemical and physical properties. For its interesting properties, the polymer has been implied for several applications, including sensing. In this work, we investigated how to use functionalized PDMS membranes as sensing elements in optical sensors for gas detection in water samples. Keywords: Polydimethylsiloxane (PDMS, Surface Plasmon Resonance (SPR sensors, Gas sensor

  20. Relational-Based Sensor Data Cleansing

    DEFF Research Database (Denmark)

    Iftikhar, Nadeem; Liu, Xiufeng; Nordbjerg, Finn Ebertsen

    2015-01-01

    cleansing approaches, such as classification, prediction and moving average are not suited for embedded sensor devices, due to the limited storage and processing capabilities. In this paper, we propose a sensor data cleansing approach using the relational-based technologies, including constraints, triggers...... and granularity-based data aggregation. The proposed approach is simple but effective to cleanse different types of dirty data, including delayed data, incomplete data, incorrect data, duplicate data and missing data. We evaluate the proposed strategy to verify its efficiency, effectiveness and adaptability.......Today sensors are widely used in many monitoring applications. Due to some random environmental effects and/or sensing failures, the collected sensor data is typically noisy. Thus, it is critical to cleanse the sensor data before using it to answer queries or conduct data analysis. Popular data...

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

    Science.gov (United States)

    Ko, Teresa H [Castro Valley, CA; Berry, Nina M [Tracy, CA

    2011-09-20

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

  2. Glucose determination using a re-usable enzyme-modified ion track membrane sensor

    Czech Academy of Sciences Publication Activity Database

    Fink, Dietmar; Klinkovich, I.; Bukelman, O.; Marks, R.S.; Kiv, A.; Fuks, D.; Fahrner, W. R.; Alfonta, L.

    2009-01-01

    Roč. 24, č. 8 (2009), s. 2702-2706 ISSN 0956-5663 Institutional research plan: CEZ:AV0Z10480505 Keywords : Glucose sensor * etched tracks * Ion track membranes Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 5.429, year: 2009

  3. Poly(vinyl alcohol)-heparin hydrogels as sensor catheter membranes

    NARCIS (Netherlands)

    Brinkman, E.; van der Does, L.; Bantjes, A.

    1991-01-01

    Poly(vinyl alcohol)-heparin hydrogels with varying water content were synthesized for use as sensor catheter membranes. Films were cast from aqueous mixtures of poly(viny) alcohol) (PVA), a photosensitive cross-linker p-diazonium diphenyl amine polymer (PA), glutaraldehyde (GA) and heparin. After

  4. Sensor-based learning support

    NARCIS (Netherlands)

    Schneider, Jan

    2017-01-01

    In recent years sensor devices have become increasingly popular. Everyday objects which previously seemed to be unanimated, are turning into smart devices with the capability to sense the environment, integrate and present digital information and services for nearly every situation and context. The

  5. Development of a Portable Taste Sensor with a Lipid/Polymer Membrane

    Directory of Open Access Journals (Sweden)

    Kiyoshi Toko

    2013-01-01

    Full Text Available We have developed a new portable taste sensor with a lipid/polymer membrane and conducted experiments to evaluate the sensor’s performance. The fabricated sensor consists of a taste sensor chip (40 mm × 26 mm × 2.2 mm with working and reference electrodes and a portable sensor device (80 mm × 25 mm × 20 mm. The working electrode consists of a taste-sensing site comprising a poly(hydroxyethylmethacrylate (pHEMA hydrogel layer with KCl as the electrolyte layer and a lipid/polymer membrane as the taste sensing element. The reference electrode comprises a polyvinyl chloride (PVC membrane layer with a small hole and a pHEMA layer with KCl. The whole device is the size of a USB memory stick, making it suitable for portable use. The sensor’s response to tannic acid as the standard astringency substance showed good accuracy and reproducibility, and was comparable with the performance of a commercially available taste sensing system. Thus, it is possible for this sensor to be used for in-field evaluations and it can make a significant contribution to the food industry, as well as in various fields of research.

  6. Application of N-Quinoline-2-carboxamido-8-aminoquinoline in Fabrication of a Ho(III-PVC Membrane Sensor

    Directory of Open Access Journals (Sweden)

    Hassan Ali Zamani

    2011-01-01

    Full Text Available The N-quinoline-2-carboxamido-8-aminoquinoline (QCA was used as a suitable ion carrier in the construction of a Ho(III PVC-based membrane sensor. This sensor demonstrated good selectivity and sensitivity towards the holmium ion for a broad variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The proposed electrode exhibits a linear dynamic range between 1.0×10-6 and 1.0×10-2 M, with a near Nernstian slope of 20.4±0.3 mV per decade and a detection limit of 4.2×10-7 M. The best performance was obtained with a membrane composition of 30% poly(vinyl chloride, 56% nitrobenzene, 2% sodium tetraphenyl borate, 10% oleic acid and 2% QCA. The potentiometric response of the constructed electrode is pH independent in the range of 2.4-7.4. The sensor possesses the advantages of short conditioning time, fast response time (∼ 5 s and especially, good selectivity towards transition and heavy metal and some mono, di and trivalent cations. The Ho3+ sensor was successfully applied as an indicator electrode in the potentiometric titration of Ho(III ions with EDTA. The electrode was also used for the determination of Ho3+ ions in mixtures of different ions and the determination of the fluoride ion in mouth wash solutions.

  7. SU-8 Based Piezoresistive Mechanical Sensor

    DEFF Research Database (Denmark)

    Thaysen, Jacob; Yalcinkaya, Arda Deniz; Vestergaard, R.K.

    2002-01-01

    We present the first SU-8 based piezoresistive mechanical sensor. Conventionally, silicon has been used as a piezoresistive material due to its high gauge factor and thereby high sensitivity to strain changes in a sensor. By using the fact that SU-8 is much softer than silicon and that a gold res...... resistor is easily incorporated in SU-8, we have proven that a SU-8 based cantilever sensor is almost as sensitive to stress changes as the silicon piezoresistive cantilever. We demonstrate the chip fabrication, and characterization with respect to sensitivity, noise and device failure....

  8. Cooperative Technique Based on Sensor Selection in Wireless Sensor Network

    OpenAIRE

    ISLAM, M. R.; KIM, J.

    2009-01-01

    An energy efficient cooperative technique is proposed for the IEEE 1451 based Wireless Sensor Networks. Selected numbers of Wireless Transducer Interface Modules (WTIMs) are used to form a Multiple Input Single Output (MISO) structure wirelessly connected with a Network Capable Application Processor (NCAP). Energy efficiency and delay of the proposed architecture are derived for different combination of cluster size and selected number of WTIMs. Optimized constellation parameters are used for...

  9. Membrane-Coated Electrochemical Sensor for Corrosion Monitoring in Natural Gas Pipelines

    Directory of Open Access Journals (Sweden)

    J. Beck

    2017-07-01

    Full Text Available Electrochemical sensors can be used for a wide range of online in- situ process monitoring applications. However, the lack of a consistent electrolyte layer has previously limited electrochemical monitoring in gas and supercritical fluid streams. A solid state sensor is being designed that uses an ion conducting membrane to perform conductivity and corrosion measurements in natural gas pipelines up to 1000 psi. Initial results show that membrane conductivity measurements can be correlated directly to water content down to dew points of 1°C with good linearity. Corrosion monitoring can also be performed using methods such as linear polarization resistance and electrochemical impedance spectroscopy (EIS, though care must be taken in the electrode design to minimize deviation between sensors.

  10. Soil moisture sensors based on metamaterials

    Directory of Open Access Journals (Sweden)

    Goran Kitić

    2012-12-01

    Full Text Available In this paper novel miniature metamaterial-based soil moisture sensors are presented. The sensors are based on resonant-type metamaterials and employ split-ring resonators (SRR, spiral resonators and fractal SRRs to achieve small dimensions, high sensitivity, and compatibility with standard planar fabrication technologies. All these features make the proposedsensors suitable for deployment in agriculture for precise mapping of soil humidity.

  11. A carbon nanotube-based pressure sensor

    Science.gov (United States)

    Karimov, Kh S.; Saleem, M.; Karieva, Z. M.; Khan, Adam; Qasuria, T. A.; Mateen, A.

    2011-06-01

    In this study, a carbon nanotube (CNT)-based Al/CNT/Al pressure sensor was designed, fabricated and investigated. The sensor was fabricated by depositing CNTs on an adhesive elastic polymer tape and placing this in an elastic casing. The diameter of multiwalled nanotubes varied between 10 and 30 nm. The nominal thickness of the CNT layers in the sensors was in the range ~300-430 μm. The inter-electrode distance (length) and the width of the surface-type sensors were in the ranges 4-6 and 3-4 mm, respectively. The dc resistance of the sensors decreased 3-4 times as the pressure was increased up to 17 kN m-2. The resistance-pressure relationships were simulated.

  12. -Means Based Fingerprint Segmentation with Sensor Interoperability

    Directory of Open Access Journals (Sweden)

    Yang Xiukun

    2010-01-01

    Full Text Available A critical step in an automatic fingerprint recognition system is the segmentation of fingerprint images. Existing methods are usually designed to segment fingerprint images originated from a certain sensor. Thus their performances are significantly affected when dealing with fingerprints collected by different sensors. This work studies the sensor interoperability of fingerprint segmentation algorithms, which refers to the algorithm's ability to adapt to the raw fingerprints obtained from different sensors. We empirically analyze the sensor interoperability problem, and effectively address the issue by proposing a -means based segmentation method called SKI. SKI clusters foreground and background blocks of a fingerprint image based on the -means algorithm, where a fingerprint block is represented by a 3-dimensional feature vector consisting of block-wise coherence, mean, and variance (abbreviated as CMV. SKI also employs morphological postprocessing to achieve favorable segmentation results. We perform SKI on each fingerprint to ensure sensor interoperability. The interoperability and robustness of our method are validated by experiments performed on a number of fingerprint databases which are obtained from various sensors.

  13. Graphene-Paper Based Electrochemical Sensors

    DEFF Research Database (Denmark)

    Zhang, Minwei; Halder, Arnab; Cao, Xianyi

    2017-01-01

    Graphene paper as a new form of graphene-supported nanomaterials has received worldwideattention since its first report in 2007. Due to their high flexibility, lightweight andgood electrical conductivity, graphene papers have demonstrated the promising potentialfor crucial applications...... in electrochemical sensors and energy technologies amongothers. In this chapter, we present some examples to overview recent advances in theresearch and development of two-dimensional (2D) graphene papers as new materialsfor electrochemical sensors. The chapter covers the design, fabrication, functionalizationand...... application evaluations of graphene papers. We first summarize the mainstreammethods for fabrication of graphene papers/membranes, with the focus on chemicalvapour deposition techniques and solution-processing assembly approaches. A largeportion of this chapter is then devoted to the highlights of specific...

  14. Gas Sensors Based on Electrodeposited Polymers

    Directory of Open Access Journals (Sweden)

    Boris Lakard

    2015-07-01

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

  15. Relational-Based Sensor Data Cleansing

    DEFF Research Database (Denmark)

    Iftikhar, Nadeem; Nordbjerg, Finn Ebertsen

    2015-01-01

    approaches, such as classification, prediction and moving average, are not suited for embedded sensor devices, due to their limit storage and processing capabilities. In this paper, we propose a sensor data cleansing approach using the relational-based technologies, including constraints, triggers...... and granularity-based data aggregation. The proposed approach is simple but effective to cleanse different types of dirty data, including delayed data, incomplete data, incorrect data, duplicate data and missing data. We evaluate the proposed strategy to verify its efficiency and effectiveness.......Today sensors are widely used in many monitoring applications. Due to some random environmental effects and/or sensing failures, the collected sensor data is typically noisy. Thus, it is critical to cleanse the data before using it for answering queries or for data analysis. Popular data cleansing...

  16. HIGH PERFORMANCE CERIA BASED OXYGEN MEMBRANE

    DEFF Research Database (Denmark)

    2014-01-01

    The invention describes a new class of highly stable mixed conducting materials based on acceptor doped cerium oxide (CeO2-8 ) in which the limiting electronic conductivity is significantly enhanced by co-doping with a second element or co- dopant, such as Nb, W and Zn, so that cerium and the co-...... thin film membrane devices using these materials....

  17. A photodiode based miniature sun sensor

    International Nuclear Information System (INIS)

    Lü, Xiaozhou; Tao, Yebo; Xie, Kai; Wang, Songlin; Li, Xiaoping; Bao, Weimin; Chen, Renjie

    2017-01-01

    The solar vector is one of the most important parameters for attitude control of nanosatellites. This attitude control must be achieved without the sensors adding significantly to its size or mass. This paper presents a photodiode-based miniature sun sensor, which consists of two triangular pyramidal sensor unit structures, with each unit comprising three micro-silicon photodiodes. The two sensor units are installed on the diagonal of the nanosatellite to form a complete sun sensor capable of achieving a full-field range of solar vector measurements. In this paper, the mathematical model of the short-circuit currents of the silicon photodiodes as a function of the solar vector coordinates is deduced. A sensor sample was built and installed on a nanosatellite model, and the temperature compensation coefficient of the silicon photodiodes was obtained experimentally. The dynamic characteristic, linearity, hysteresis and repeatability of the component were measured. The sun sensor introduced in this paper can be placed on any satellite platform to allow a full range solar vector measurement, and this would result in an increase of only 1.86 g and 0.9 cm 3 of the satellite’s mass and volume, respectively. (paper)

  18. Nanostructured Polysulfone-Based Block Copolymer Membranes

    KAUST Repository

    Xie, Yihui

    2016-05-01

    The aim of this work is to fabricate nanostructured membranes from polysulfone-based block copolymers through self-assembly and non-solvent induced phase separation. Block copolymers containing polysulfone are novel materials for this purpose providing better mechanical and thermal stability to membranes than polystyrene-based copolymers, which have been exclusively used now. Firstly, we synthesized a triblock copolymer, poly(tert-butyl acrylate)-b-polsulfone-b-poly(tert-butyl acrylate) through polycondensation and reversible addition-fragmentation chain-transfer polymerization. The obtained membrane has a highly porous interconnected skin layer composed of elongated micelles with a flower-like arrangement, on top of the graded finger-like macrovoids. Membrane surface hydrolysis was carried out in a combination with metal complexation to obtain metal-chelated membranes. The copper-containing membrane showed improved antibacterial capability. Secondly, a poly(acrylic acid)-b-polysulfone-b-poly(acrylic acid) triblock copolymer obtained by hydrolyzing poly(tert-butyl acrylate)-b-polsulfone-b-poly(tert-butyl acrylate) formed a thin film with cylindrical poly(acrylic acid) microdomains in polysulfone matrix through thermal annealing. A phase inversion membrane was prepared from the same polymer via self-assembly and chelation-assisted non-solvent induced phase separation. The spherical micelles pre-formed in a selective solvent mixture packed into an ordered lattice in aid of metal-poly(acrylic acid) complexation. The space between micelles was filled with poly(acrylic acid)-metal complexes acting as potential water channels. The silver0 nanoparticle-decorated membrane was obtained by surface reduction, having three distinct layers with different particle sizes. Other amphiphilic copolymers containing polysulfone and water-soluble segments such as poly(ethylene glycol) and poly(N-isopropylacrylamide) were also synthesized through coupling reaction and copper0-mediated

  19. Fabrication and Characterization of a Ruthenium Nitride Membrane for Electrochemical pH Sensors

    Science.gov (United States)

    Liao, Yi-Hung; Chou, Jung-Chuan

    2009-01-01

    The pH sensing and nonideal characteristics of a ruthenium nitride (RuN) sensing membrane pH sensor were investigated. RuN thin films were deposited from a 99.9% ruthenium target on p-type silicon substrates using radio frequency (r.f.) sputtering with N2 gas. Subsequently, the nanometric structure and surface morphology of RuN thin films were determined. The sensitivity of the RuN sensing membrane pH sensor was 58.03 mV/pH, obtained from ID-VG curves with a current-voltage (I–V) measurement system in standard buffer solutions from pH 1 to pH 13 at room temperature (25 °C). Moreover, the nonideal characteristics of the RuN sensing membrane, such as temperature coefficient, drift with light influence, drift rate and hysteresis width, etc. were also investigated. Finally, the sensing characteristics of the RuN membrane were compared with titanium nitride (TiN), aluminum nitride (AlN) and silicon nitride (Si3N4) membranes. PMID:22574026

  20. ELECTROCHEMICAL SYNTHEZIS AND CHARACTERIZATION OF POLYPYRROLE FOR DODECYLSULFATE SENSOR MEMBRANE

    Directory of Open Access Journals (Sweden)

    Abdul Haris Watoni

    2010-06-01

    Full Text Available A conducting polymer, polypyrrole, has been electrochemically synthesized from pyrrole monomer using cyclic voltammetry technique in aqueous solution in the presence of HDS dopant and KNO3 supporting electrolyte. The polymer was deposited on the surface of an Au-wire and the modified electrode obtained was then used as dodecylsulfate (DS- ion sensor electrode. The best performance PPy-DS modified-Au electrode conditioned in the air system without HDS or SDS solution gave linear potential response for the concentration range of 1.0 x 10-5 - 1.0 x 10-3 M, sensitivity of 54.5 mV/decade, detection limit of 1.0 x 10-5 M, and response time of 23 - 30 second.  The electrode showed good selectivity towards other anions, therefore can be used to determine SDS concentration in real samples system without any change of the samples matrix.   Keywords: polypyrrole, SDS, cyclic voltammetry

  1. MWCNTs based flexible and stretchable strain sensors

    Science.gov (United States)

    Khan, Saeed Ahmed; Gao, Min; Zhu, Yuechang; Yan, Zhuocheng; Lin, Yuan

    2017-06-01

    Carbon nanotubes have potential applications in flexible and stretchable devices due to their remarkable electromechanical properties. Flexible and stretchable strain sensors of multi-walled carbon nanotubes (MWCNTs) with aligned or random structures were fabricated on poly-dimethylsiloxane (PDMS) substrate with different techniques. It was observed that the spraycoatedtechniquebased strain sensor fabricated on PDMS substrate showed higher sensitivity higher stretchability, better linearity and excellent longer time stability than the sensor fabricated with other methods presented in this work. The scanning electron microscopy images indicated the spray coating technique can produce a better uniform and compact CNT network, which is the important role affecting the performance of CNT-based flexible strain sensors. Project supported by the National Basic Research Program of China (No. 2015CB351905), the National Natural Science Foundation of China (No. 61306015), the Technology Innovative Research Team of Sichuan Province of China (No.2015TD0005), and “111” Project (No. B13042)

  2. Thermal properties of calorimeters with Ti/Au transition-edge sensors on silicon nitride membranes

    International Nuclear Information System (INIS)

    Ukibe, M.; Tanaka, K.; Koyanagi, M.; Morooka, T.; Pressler, H.; Ohkubo, M.; Kobayashi, N.

    2000-01-01

    We are developing X-ray microcalorimeters employing superconducting-transition-edge sensors (TESs) for relatively high operation-temperatures of an 3 He cryostat. The TESs are proximity bilayers of Ti and Au. An important thermal parameters, the thermal conductance G, of the microcalorimeters on SiN x membranes was evaluated by a simple method using R-T curves at different bias currents. It has been shown that the G value can be controlled by altering the membrane thickness and size

  3. Pristine carbon nanotubes based resistive temperature sensor

    International Nuclear Information System (INIS)

    Alam, Md Bayazeed; Saini, Sudhir Kumar; Sharma, Daya Shankar; Agarwal, Pankaj B.

    2016-01-01

    A good sensor must be highly sensitive, faster in response, of low cost cum easily producible, and highly reliable. Incorporation of nano-dimensional particles/ wires makes conventional sensors more effective in terms of fulfilling the above requirements. For example, Carbon Nanotubes (CNTs) are promising sensing element because of its large aspect ratio, unique electronic and thermal properties. In addition to their use for widely reported chemical sensing, it has also been explored for temperature sensing. This paper presents the fabrication of CNTs based temperature sensor, prepared on silicon substrate using low cost spray coating method, which is reliable and reproducible method to prepare uniform CNTs thin films on any substrate. Besides this, simple and inexpensive method of preparation of dispersion of single walled CNTs (SWNTs) in 1,2 dichlorobenzene by using probe type ultrasonicator for debundling the CNTs for improving sensor response were used. The electrical contacts over the dispersed SWNTs were taken using silver paste electrodes. Fabricated sensors clearly show immediate change in resistance as a response to change in temperature of SWNTs. The measured sensitivity (change in resistance with temperature) of the sensor was found ∼ 0.29%/°C in the 25°C to 60°C temperature range.

  4. Pristine carbon nanotubes based resistive temperature sensor

    Energy Technology Data Exchange (ETDEWEB)

    Alam, Md Bayazeed, E-mail: bayazeed786@gmail.com [CSIR-Central Electronics Engineering Research Institute (CEERI, Pilani, India) (India); Jamia Millia Islamia (New Delhi, India) (India); Saini, Sudhir Kumar, E-mail: sudhirsaini1310@gmail.com [CSIR-Central Electronics Engineering Research Institute (CEERI, Pilani, India) (India); Sharma, Daya Shankar, E-mail: dssharmanit15@gmail.com [CSIR-Central Electronics Engineering Research Institute (CEERI, Pilani, India) (India); Maulana Azad National Institute of Technology (MANIT, Bhopal, India) (India); Agarwal, Pankaj B., E-mail: agarwalbpankj@gmail.com [CSIR-Central Electronics Engineering Research Institute (CEERI, Pilani, India) (India); Academy for Scientific and Innovative Research (AcSIR, Delhi, India) (India)

    2016-04-13

    A good sensor must be highly sensitive, faster in response, of low cost cum easily producible, and highly reliable. Incorporation of nano-dimensional particles/ wires makes conventional sensors more effective in terms of fulfilling the above requirements. For example, Carbon Nanotubes (CNTs) are promising sensing element because of its large aspect ratio, unique electronic and thermal properties. In addition to their use for widely reported chemical sensing, it has also been explored for temperature sensing. This paper presents the fabrication of CNTs based temperature sensor, prepared on silicon substrate using low cost spray coating method, which is reliable and reproducible method to prepare uniform CNTs thin films on any substrate. Besides this, simple and inexpensive method of preparation of dispersion of single walled CNTs (SWNTs) in 1,2 dichlorobenzene by using probe type ultrasonicator for debundling the CNTs for improving sensor response were used. The electrical contacts over the dispersed SWNTs were taken using silver paste electrodes. Fabricated sensors clearly show immediate change in resistance as a response to change in temperature of SWNTs. The measured sensitivity (change in resistance with temperature) of the sensor was found ∼ 0.29%/°C in the 25°C to 60°C temperature range.

  5. Miniaturizable Ion-Selective Arrays Based on Highly Stable Polymer Membranes for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Mònica Mir

    2014-07-01

    Full Text Available Poly(vinylchloride (PVC is the most common polymer matrix used in the fabrication of ion-selective electrodes (ISEs. However, the surfaces of PVC-based sensors have been reported to show membrane instability. In an attempt to overcome this limitation, here we developed two alternative methods for the preparation of highly stable and robust ion-selective sensors. These platforms are based on the selective electropolymerization of poly(3,4-ethylenedioxythiophene (PEDOT, where the sulfur atoms contained in the polymer covalently interact with the gold electrode, also permitting controlled selective attachment on a miniaturized electrode in an array format. This platform sensor was improved with the crosslinking of the membrane compounds with poly(ethyleneglycol diglycidyl ether (PEG, thus also increasing the biocompatibility of the sensor. The resulting ISE membranes showed faster signal stabilization of the sensor response compared with that of the PVC matrix and also better reproducibility and stability, thus making these platforms highly suitable candidates for the manufacture of robust implantable sensors.

  6. Optical acetylcholine sensor based on free base porphyrin as a chromoionophore.

    Science.gov (United States)

    Mroczkiewicz, Monika; Pietrzak, Mariusz; Górski, Łukasz; Malinowska, Elżbieta

    2011-09-21

    In this work, the possibility of application of free base porphyrin as a lipophilic pH chromoionophore for the preparation of optical cation-selective sensors was investigated. The properties of polymeric membranes, containing porphyrins of different structures, namely tetraphenylporphyrin (TPP) and octaethylporphyrin (OEP), were compared. Changes in equilibrium between protonated and deprotonated form of porphyrin, resulting from variations in ACh concentration, were evaluated. The influence of various factors (kind and quantity of anionic additive and porphyrin in the membrane phase, pH of sample solution) on initial equilibrium was studied. The best membrane composition was chosen as: TPP 3 wt.%, KTFPB 175 mol.% relative to ionophore, PVC:o-NPOE (1 : 4) and measuring buffer solution: 0.05 M MES, pH 4.5. Selectivity, response stability, reversibility and repeatability tests were carried out for chosen sensor. Developed sensor allowed for the determination of a model analyte, acetylcholine, at the concentration range of 10(-5) to 10(-2) M, both in stationary and flow-injection system. Sensor response was reversible and repeatable in the mentioned concentration range.

  7. Sensor Fusion-based Event Detection in Wireless Sensor Networks

    NARCIS (Netherlands)

    Bahrepour, M.; Meratnia, Nirvana; Havinga, Paul J.M.

    2009-01-01

    Recently, Wireless Sensor Networks (WSN) community has witnessed an application focus shift. Although, monitoring was the initial application of wireless sensor networks, in-network data processing and (near) real-time actuation capability have made wireless sensor networks suitable candidate for

  8. Portable e-Tongue based on Multi-channel LAPS Array with PVC Membrane for Rapid Environment Detection

    Science.gov (United States)

    Ha, D.; Yu, H.; Hu, N.; Wu, C. X.; Zhou, J.; Kirsanov, Dmitry; Legin, Andrey; Wang, P.

    2011-09-01

    A new kind of portable e-Tongue based on multi-channel LAPS array with PVC membrane has been designed for the rapid detection of environment situation, especially the seawater. It has the great advantages of depositing membranes which are offered by Chemistry Department, Saint-Petersburg State University on the sensors artificially with convenience and efficiency. To detect various heavy metal ions (Pb2+, Cd2+, Zn2+) simultaneously, respective Polyvinyl Chloride (PVC) membrane could be prepared on the surface of the silicon-based sensor in different channel.

  9. Optical Ring Resonator Based Temperature Sensor

    Science.gov (United States)

    Addya, Subhankar; Dey, Sabitabrata; Mandal, Sanjoy

    2017-12-01

    Temperature sensor based on optical ring resonator has been demonstrated with its constituent material as silicon (Si-fiber) and germanium (Ge-fiber) in this work. It has been done through optical delay line signal processing technique in Z-domain. The group indices of both the materials vary with the change in temperature due to the thermo-optic effect in materials. Thus temperature dependence of free spectral range forms the basis of modeling the sensors. Silicon (Si) fiber based optical sensor can sense the temperature in the range 30-500 °C and that for germanium (Ge) fiber the range is -25 to 300 °C. Obtained temperature sensitivities for Ge and Si-fibers are 5.55 and 2.97 MHz/°C respectively.

  10. Fuzzy-Based Sensor Fusion for Cognitive Radio-Based Vehicular Ad Hoc and Sensor Networks

    Directory of Open Access Journals (Sweden)

    Mohammad Jalil Piran

    2015-01-01

    Full Text Available In wireless sensor networks, sensor fusion is employed to integrate the acquired data from diverse sensors to provide a unified interpretation. The best and most salient advantage of sensor fusion is to obtain high-level information in both statistical and definitive aspects, which cannot be attained by a single sensor. In this paper, we propose a novel sensor fusion technique based on fuzzy theory for our earlier proposed Cognitive Radio-based Vehicular Ad Hoc and Sensor Networks (CR-VASNET. In the proposed technique, we considered four input sensor readings (antecedents and one output (consequent. The employed mobile nodes in CR-VASNET are supposed to be equipped with diverse sensors, which cater to our antecedent variables, for example, The Jerk, Collision Intensity, and Temperature and Inclination Degree. Crash_Severity is considered as the consequent variable. The processing and fusion of the diverse sensory signals are carried out by fuzzy logic scenario. Accuracy and reliability of the proposed protocol, demonstrated by the simulation results, introduce it as an applicable system to be employed to reduce the causalities rate of the vehicles’ crashes.

  11. Fabrication and Characterization of a Pressure Sensor using a Pitch-based Carbon Fiber

    International Nuclear Information System (INIS)

    Park, Chang Sin; Kang, Bo Seon; Lee, Dong Weon

    2007-01-01

    This paper reports fabrication and characterization of a pressure sensor using a pitch-based carbon fiber. Pitch-based carbon fibers have been shown to exhibit the piezoresistive effect, in which the electric resistance of the carbon fiber changes under mechanical deformation. The main structure of pressure sensors was built by performing backside etching on a SOI wafer and creating a suspended square membrane on the front side. An AC electric field which causes dielectrophoresis was used for the alignment and deposition of a carbon fiber across the microscale gap between two electrodes on the membrane. The fabricated pressure sensors were tested by applying static pressure to the membrane and measuring the resistance change of the carbon fiber. The resistance change of carbon fibers clearly shows linear response to the applied pressure and the calculated sensitivities of pressure sensors are 0.25∼0.35 and 61.8 Ω/kΩ·bar for thicker and thinner membrane, respectively. All these observations demonstrated the possibilities of carbon fiber-based pressure sensors

  12. Electrode-analytical properties of polyvinylchloride membranes based on triple metal-polymeric complexes

    Directory of Open Access Journals (Sweden)

    Katerina V. Matorina

    2015-10-01

    Full Text Available The influence of the nature of the electrode-active substances (EAS, the composition of the external and internal solutions on the formation of the analytical signal of polyvinylchloride (PVC membranes based on associates and triple metal-polymeric complexes (TMPC was established. Dehumidification of synthesized membranes increases with the content of polyvinylpyrrolidone (PVP. The value of the swelling degree is more than two times greater for membranes, which contain as EAS TMPC, relative to membranes based on associates. The value of water absorption of membranes is determined by the nature of EAS. They formed a series of increasing of the swelling degree such as associate < background membrane < TMPC. Swelling of the background membrane is explained by the physical sorption of water molecules on the surface of plasticized membrane. Hydration of PVP macromolecules varies with the introduction of metal ions, macromolecules unit undergoes a conformational transition. PVP macromolecules form tunnels or cavities where complex particles distributed and additional water accumulated through the second coordination layer. Constructed sensors based on TMPC have slope of electrode function equal to 25 mV/pC. Linear dependence of potential on the polymer concentration is observed in the range of 5–7 pC units. Sensors based on associates have slope of the electrode function of 20–25 mV/pC that can be varied depending on the nature of the EAS. Working range is 4–8 pC. Response time of sensor is less than 1 min. The optimal time for conditioning of the synthesized PVC membrane is 24 hours. Potentiometric sensors have been developed for the determination of residual amounts of low molecular PVP which is a food additive E 1201 commonly used for thickening, stabilizing and clarifying of food products. The content of PVP was determined in real objects (apple juice, beer, red wine and cognac with using the polyvinylpyrrolidone sensors (Sr < 0.08. The

  13. Sensors

    CERN Document Server

    Pigorsch, Enrico

    1997-01-01

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

  14. Sensors

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-10-01

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

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

    Science.gov (United States)

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

    2013-07-01

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

  16. Miniaturized optical sensors based on lens arrays

    DEFF Research Database (Denmark)

    Hanson, Steen Grüner; Jakobsen, M.L.; Larsen, H.E.

    2005-01-01

    A suite of optical sensors based on the use of lenticular arrays for probing mechanical deflections will be displayed. The optical systems are well suited for miniaturization, and utilize speckles as the information-carriers. This implementation allows for acquiring directional information...

  17. Flexible optical fiber sensor based on polyurethane

    DEFF Research Database (Denmark)

    Kaysir, Md Rejvi; Stefani, Alessio; Lwin, Richard

    Polyurethane (PU) based hollow core fibers are investigated as optical sensors. The flexibility of PU fibers makes it suitable for sensing mechanical perturbations. We fabricated a PU fiber using the fiber drawing method, characterized the fiber and experimentally demonstrated a simple way...

  18. Towards Reproducible Ring Resonator Based Temperature Sensors

    Directory of Open Access Journals (Sweden)

    Nikolai KLIMOV

    2015-08-01

    Full Text Available In recent years photonic devices have emerged as a powerful tool for developing novel, high-sensitivity sensors. In particular, tremendous progress has been reported in developing photonic temperature sensors using a wide variety of materials including optical fiber and on-chip silicon photonic devices. We recently reported on ultra high sensitivity temperature sensor based on silicon ring resonator structure that has a noise floor of 80 µK. Here we have systematically examined the impact of structural parameters on the performance of silicon ring resonator photonic thermometers. Our results suggest that consistently high performance temperature sensors are obtained from the zone of stability (waveguide width > 600 nm, air gap » 130 nm and ring radius >10 µm such that quality factors are consistent » 104 and the temperature sensitivity is in the 70 pm/K to 80 pm/K range. The zone of stability identified in this work is a useful starting point for future testing of inter-changeability wafer-scale produced sensors.

  19. Physiological Sensor Signals Classification for Healthcare Using Sensor Data Fusion and Case-Based Reasoning

    OpenAIRE

    Begum, Shahina; Barua, Shaibal; Ahmed, Mobyen Uddin

    2014-01-01

    Today, clinicians often do diagnosis and classification of diseases based on information collected from several physiological sensor signals. However, sensor signal could easily be vulnerable to uncertain noises or interferences and due to large individual variations sensitivity to different physiological sensors could also vary. Therefore, multiple sensor signal fusion is valuable to provide more robust and reliable decision. This paper demonstrates a physiological sensor signal classificati...

  20. Physiological roles of acid-base sensors.

    Science.gov (United States)

    Levin, Lonny R; Buck, Jochen

    2015-01-01

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

  1. Gas Sensors Based on Molecular Imprinting Technology.

    Science.gov (United States)

    Zhang, Yumin; Zhang, Jin; Liu, Qingju

    2017-07-04

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

  2. Gallium nitride electrodes for membrane-based electrochemical biosensors.

    Science.gov (United States)

    Schubert, T; Steinhoff, G; von Ribbeck, H-G; Stutzmannn, M; Eickhoff, M; Tanaka, M

    2009-10-01

    We report on the deposition of planar lipid bilayers (supported membranes) on gallium nitride (GaN) electrodes for potential applications as membrane-based biosensors. The kinetics of the lipid membrane formation upon vesicle fusion were monitored by simultaneous measurements of resistance and capacitance of the membrane using AC impedance spectroscopy in the frequency range between 50 mHz and 50 kHz. We could identify a two-step process of membrane spreading and self-healing. Despite its relatively low resistance, the membrane can be modeled by a parallel combination of an ideal resistor and capacitor, indicating that the membrane efficiently blocks the diffusion of ions.

  3. Contact State Estimation by Vision-based Tactile Sensors for Dexterous Manipulation with Robot Hands Based on Shape-Sensing

    Directory of Open Access Journals (Sweden)

    Yuji Ito

    2011-09-01

    Full Text Available We propose a new method for estimating the contact state of objects with varying shapes on a vision‐ based fluid‐type tactile sensor, which touch pad is an elastic transparent membrane of silicon rubber with dotted pattern printed on its inner side. The membrane is filled with translucent red colored water. The proposed method leads to better understanding of the object

  4. Contact State Estimation by Vision-Based Tactile Sensors for Dexterous Manipulation with Robot Hands Based on Shape-Sensing

    Directory of Open Access Journals (Sweden)

    Yuji Ito

    2011-09-01

    Full Text Available We propose a new method for estimating the contact state of objects with varying shapes on a vision-based fluid-type tactile sensor, which touch pad is an elastic transparent membrane of silicon rubber with dotted pattern printed on its inner side. The membrane is filled with translucent red colored water. The proposed method leads to better understanding of the object's shape and movement, and can be applied for accomplishing reliable and dexterous handling tasks by robot hands.

  5. Carbon paste- and PVC membrane electrodes as sensitive sensors for the determination of antidiabetic drugs for type 2 diabetic patients.

    Science.gov (United States)

    Badawy, Waheed A; El-Ries, Mohammed A; Mahdi, Inas M

    2009-12-01

    Carbon paste- and polyvinyl chloride membrane electrodes are simple, precise, rapid and selective sensors for the determination of antidiabetic drugs for type 2 diabetic patients. These electrodes were successfully used for the potentiometric determination of rosiglitazone, pioglitazone, glimepiride and glyburide in their standard forms and also as pharmaceutical preparations. The preparation of these ion-selective electrodes for the potentiometric determination of the drug is based on the construction of a 10% standard drug-ion pair with reineckate or tungstophosphate imbedded as an electro-active material in the carbon paste or in the polyvinyl chloride membrane. The prepared ion-selective electrodes showed a Nernstian response with a limit of detection amounting to 10(-6) M in a pH range of 3 to 5. A good selectivity coefficient and long term stability could be achieved. The developed potentiometric method based on the CPE and PVC sensors is economic and less time consuming compared to the conventionally used high performance liquid chromatography, HPLC, methods.

  6. Contactless Quality Monitoring Sensor Based on Electrical Conductivity Measurements

    Directory of Open Access Journals (Sweden)

    Armin SATZ

    2010-09-01

    Full Text Available A first prototype of a contactless conductivity sensor for AdBlue® quality monitoring is presented. Based on a detailed sensor mode analysis it is shown that capacitive sensors can be designed to sense electrical liquid conductivity. The sensor design process is based on a sensor model, which allows simulating capacitive senor responses for arbitrary electrode and liquid tank geometries. Finally, temperature induced errors are estimated.

  7. Model-based Sensor Data Acquisition and Management

    OpenAIRE

    Aggarwal, Charu C.; Sathe, Saket; Papaioannou, Thanasis G.; Jeung, Ho Young; Aberer, Karl

    2012-01-01

    In recent years, due to the proliferation of sensor networks, there has been a genuine need of researching techniques for sensor data acquisition and management. To this end, a large number of techniques have emerged that advocate model-based sensor data acquisition and management. These techniques use mathematical models for performing various, day-to-day tasks involved in managing sensor data. In this chapter, we survey the state-of-the-art techniques for model-based sensor data acquisition...

  8. Membrane Based Measurement Technology for in situ Monitoring of Gases in Soil

    Directory of Open Access Journals (Sweden)

    Helmut Geistlinger

    2009-02-01

    Full Text Available The representative measurement of gas concentration and fluxes in heterogeneous soils is one of the current challenges when analyzing the interactions of biogeochemical processes in soils and global change. Furthermore, recent research projects on CO2-sequestration have an urgent need of CO2-monitoring networks. Therefore, a measurement method based on selective permeation of gases through tubular membranes has been developed. Combining the specific permeation rates of gas components for a membrane and Dalton’s principle, the gas concentration (or partial pressure can be determined by the measurement of physical quantities (pressure or volume only. Due to the comparatively small permeation constants of membranes, the influence of the sensor on its surrounding area can be neglected. The design of the sensor membranes can be adapted to the spatial scale from the bench scale to the field scale. The sensitive area for the measurement can be optimized to obtain representative results. Furthermore, a continuous time-averaged measurement is possible where the time for averaging is simply controlled by the wall-thickness of the membrane used. The measuring method is demonstrated for continuous monitoring of O2 and CO2 inside of a sand filled Lysimeter. Using three sensor planes inside the sand pack, which were installed normal to the gas flow direction and a reference measurement system, we demonstrate the accuracy of the gas-detection for different flux-based boundary conditions.

  9. Touch-mode capacitive pressure sensor with graphene-polymer heterostructure membrane

    Science.gov (United States)

    Berger, Christian; Phillips, Rory; Pasternak, Iwona; Sobieski, Jan; Strupinski, Wlodek; Vijayaraghavan, Aravind

    2018-01-01

    We describe the fabrication and characterisation of a touch-mode capacitive pressure sensor (TMCPS) with a robust design that comprises a graphene-polymer heterostructure film, laminated onto the silicon dioxide surface of a silicon wafer, incorporating a SU-8 spacer grid structure. The spacer grid structure allows the flexible graphene-polymer film to be partially suspended above the substrate, such that a pressure on the membrane results in a reproducible deflection, even after exposing the membrane to pressures over 10 times the operating range. Sensors show reproducible pressure transduction in water submersion at varying depths under static and dynamic loading. The measured capacitance change in response to pressure is in good agreement with an analytical model of clamped plates in touch mode. The device shows a pressure sensitivity of 27.1 +/- 0.5 fF Pa-1 over a pressure range of 0.5 kPa-8.5 kPa. In addition, we demonstrate the operation of this device as a force-touch sensor in air.

  10. Sensor-based interior modeling

    International Nuclear Information System (INIS)

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

    1995-01-01

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

  11. Organic electronics based pressure sensor towards intracranial pressure monitoring

    Science.gov (United States)

    Rai, Pratyush; Varadan, Vijay K.

    2010-04-01

    The intra-cranial space, which houses the brain, contains cerebrospinal fluid (CSF) that acts as a fluid suspension medium for the brain. The CSF is always in circulation, is secreted in the cranium and is drained out through ducts called epidural veins. The venous drainage system has inherent resistance to the flow. Pressure is developed inside the cranium, which is similar to a rigid compartment. Normally a pressure of 5-15 mm Hg, in excess of atmospheric pressure, is observed at different locations inside the cranium. Increase in Intra-Cranial Pressure (ICP) can be caused by change in CSF volume caused by cerebral tumors, meningitis, by edema of a head injury or diseases related to cerebral atrophy. Hence, efficient ways of monitoring ICP need to be developed. A sensor system and monitoring scheme has been discussed here. The system architecture consists of a membrane less piezoelectric pressure sensitive element, organic thin film transistor (OTFT) based signal transduction, and signal telemetry. The components were fabricated on flexible substrate and have been assembled using flip-chip packaging technology. Material science and fabrication processes, subjective to the device performance, have been discussed. Capability of the device in detecting pressure variation, within the ICP pressure range, is investigated and applicability of measurement scheme to medical conditions has been argued for. Also, applications of such a sensor-OTFT assembly for logic sensor switching and patient specific-secure monitoring system have been discussed.

  12. Wireless Sensor Network Based Smart Parking System

    Directory of Open Access Journals (Sweden)

    Jeffrey JOSEPH

    2014-01-01

    Full Text Available Ambient Intelligence is a vision in which various devices come together and process information from multiple sources in order to exert control on the physical environment. In addition to computation and control, communication plays a crucial role in the overall functionality of such a system. Wireless Sensor Networks are one such class of networks, which meet these criteria. These networks consist of spatially distributed sensor motes which work in a co-operative manner to sense and control the environment. In this work, an implementation of an energy-efficient and cost-effective, wireless sensor networks based vehicle parking system for a multi-floor indoor parking facility has been introduced. The system monitors the availability of free parking slots and guides the vehicle to the nearest free slot. The amount of time the vehicle has been parked is monitored for billing purposes. The status of the motes (dead/alive is also recorded. Information like slot allocated, directions to the slot and billing data is sent as a message to customer’s mobile phones. This paper extends our previous work 1 with the development of a low cost sensor mote, about one tenth the cost of a commercially available mote, keeping in mind the price sensitive markets of the developing countries.

  13. Temperature characteristics research of SOI pressure sensor based on asymmetric base region transistor

    Science.gov (United States)

    Zhao, Xiaofeng; Li, Dandan; Yu, Yang; Wen, Dianzhong

    2017-07-01

    Based on the asymmetric base region transistor, a pressure sensor with temperature compensation circuit is proposed in this paper. The pressure sensitive structure of the proposed sensor is constructed by a C-type silicon cup and a Wheatstone bridge with four piezoresistors ({R}1, {R}2, {R}3 and {R}4) locating on the edge of a square silicon membrane. The chip was designed and fabricated on a silicon on insulator (SOI) wafer by micro electromechanical system (MEMS) technology and bipolar transistor process. When the supply voltage is 5.0 V, the corresponding temperature coefficient of the sensitivity (TCS) for the sensor before and after temperature compensation are -1862 and -1067 ppm/°C, respectively. Through varying the ratio of the base region resistances {r}1 and {r}2, the TCS for the sensor with the compensation circuit is -127 ppm/°C. It is possible to use this compensation circuit to improve the temperature characteristics of the pressure sensor. Project supported by the National Natural Science Foundation of China (No. 61471159), the Natural Science Foundation of Heilongjiang Province (No. F201433), the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province (No. 2015018), and the Special Funds for Science and Technology Innovation Talents of Harbin in China (No. 2016RAXXJ016).

  14. Wavefront reconstruction using smartphone based wavefront sensors

    Science.gov (United States)

    Yang, Zhenyu; Zhan, Qiwen

    2015-11-01

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

  15. Evaluation of Miniaturized Infrared Sensors for Process Control of the Palladium Membrane Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lascola, R. J.; Howard, D. W.

    2005-07-31

    We have tested the suitability of a miniaturized infrared sensor for measurements of CO and H{sub 2}O in the inlet stream to the Palladium Membrane Reactor (PMR). We demonstrated that both analytes can be measured with absolute accuracies of 2-4% at the process inlet conditions of 120-140 C and approximately 1 atm of each gas. This accuracy must be improved to 1-1.5% for effective PMR process control. The use of a reference detector and independent temperature and pressure measurements to correct the raw signals will improve the accuracy to a level that will approach, if not meet, this goal. With appropriate bandpass filters, the infrared sensors may be used for other gas analysis applications.

  16. Optical Fiber Sensors Based on Fiber Ring Laser Demodulation Technology.

    Science.gov (United States)

    Xie, Wen-Ge; Zhang, Ya-Nan; Wang, Peng-Zhao; Wang, Jian-Zhang

    2018-02-08

    A review for optical fiber sensors based on fiber ring laser (FRL) demodulation technology is presented. The review focuses on the principles, main structures, and the sensing performances of different kinds of optical fiber sensors based on FRLs. First of all, the theory background of the sensors has been discussed. Secondly, four different types of sensors are described and compared, which includes Mach-Zehnder interferometer (MZI) typed sensors, Fabry-Perot interferometer (FPI) typed sensors, Sagnac typed sensors, and fiber Bragg grating (FBG) typed sensors. Typical studies and main properties of each type of sensors are presented. Thirdly, a comparison of different types of sensors are made. Finally, the existing problems and future research directions are pointed out and analyzed.

  17. Performance of UWB Array-Based Radar Sensor in a Multi-Sensor Vehicle-Based Suit for Landmine Detection

    NARCIS (Netherlands)

    Yarovoy, A.; Savelyev, T.; Zhuge, X.; Aubry, P.; Ligthart, L.; Schavemaker, J.G.M.; Tettelaar, P.; Breejen, E. de

    2008-01-01

    In this paper, integration of an UWB array-based timedomain radar sensor in a vehicle-mounted multi-sensor system for landmine detection is described. Dedicated real-time signal processing algorithms are developed to compute the radar sensor confidence map which is used for sensor fusion.

  18. Silica incorporated membrane for wastewater based filtration

    Science.gov (United States)

    Fernandes, C. S.; Bilad, M. R.; Nordin, N. A. H. M.

    2017-10-01

    Membrane technology has long been applied for waste water treatment industries due to its numerous advantages compared to other conventional processes. However, the biggest challenge in pressure driven membrane process is membrane fouling. Fouling decreases the productivity and efficiency of the filtration, reduces the lifespan of the membrane and reduces the overall efficiency of water treatment processes. In this study, a novel membrane material is developed for water filtration. The developed membrane incorporates silica nanoparticles mainly to improve its structural properties. Membranes with different loadings of silica nanoparticles were applied in this study. The result shows an increase in clean water permeability and filterability of the membrane for treating activated sludge, microalgae solution, secondary effluent and raw sewage as feed. Adding silica into the membrane matrix does not significantly alter contact angle and membrane pore size. We believe that silica acts as an effective pore forming agent that increases the number of pores without significantly altering the pore sizes. A higher number of small pores on the surface of the membrane could reduce membrane fouling because of a low specific loading imposed to individual pores.

  19. Research on the Changes to the Lipid/Polymer Membrane Used in the Acidic Bitterness Sensor Caused by Preconditioning

    Directory of Open Access Journals (Sweden)

    Yuhei Harada

    2016-02-01

    Full Text Available A taste sensor that uses lipid/polymer membranes can evaluate aftertastes felt by humans using Change in membrane Potential caused by Adsorption (CPA measurements. The sensor membrane for evaluating bitterness, which is caused by acidic bitter substances such as iso-alpha acid contained in beer, needs an immersion process in monosodium glutamate (MSG solution, called “MSG preconditioning”. However, what happens to the lipid/polymer membrane during MSG preconditioning is not clear. Therefore, we carried out three experiments to investigate the changes in the lipid/polymer membrane caused by the MSG preconditioning, i.e., measurements of the taste sensor, measurements of the amount of the bitterness substance adsorbed onto the membrane and measurements of the contact angle of the membrane surface. The CPA values increased as the preconditioning process progressed, and became stable after 3 d of preconditioning. The response potentials to the reference solution showed the same tendency of the CPA value change during the preconditioning period. The contact angle of the lipid/polymer membrane surface decreased after 7 d of MSG preconditioning; in short, the surface of the lipid/polymer membrane became hydrophilic during MSG preconditioning. The amount of adsorbed iso-alpha acid was increased until 5 d preconditioning, and then it decreased. In this study, we revealed that the CPA values increased with the progress of MSG preconditioning in spite of the decrease of the amount of iso-alpha acid adsorbed onto the lipid/polymer membrane, and it was indicated that the CPA values increase because the sensor sensitivity was improved by the MSG preconditioning.

  20. Temperature-independent fiber-Bragg-grating-based atmospheric pressure sensor

    Science.gov (United States)

    Zhang, Zhiguo; Shen, Chunyan; Li, Luming

    2018-03-01

    Atmospheric pressure is an important way to achieve a high degree of measurement for modern aircrafts, moreover, it is also an indispensable parameter in the meteorological telemetry system. With the development of society, people are increasingly concerned about the weather. Accurate and convenient atmospheric pressure parameters can provide strong support for meteorological analysis. However, electronic atmospheric pressure sensors currently in application suffer from several shortcomings. After an analysis and discussion, we propose an innovative structural design, in which a vacuum membrane box and a temperature-independent strain sensor based on an equal strength cantilever beam structure and fiber Bragg grating (FBG) sensors are used. We provide experimental verification of that the atmospheric pressure sensor device has the characteristics of a simple structure, lack of an external power supply, automatic temperature compensation, and high sensitivity. The sensor system has good sensitivity, which can be up to 100 nm/MPa, and repeatability. In addition, the device exhibits desired hysteresis.

  1. Sensor-based material tagging system

    International Nuclear Information System (INIS)

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

    1991-01-01

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

  2. Carbon Nanotube-Based Chemical Sensors.

    Science.gov (United States)

    Meyyappan, M

    2016-04-27

    The need to sense gases and vapors arises in numerous scenarios in industrial, environmental, security and medical applications. Traditionally, this activity has utilized bulky instruments to obtain both qualitative and quantitative information on the constituents of the gas mixture. It is ideal to use sensors for this purpose since they are smaller in size and less expensive; however, their performance in the field must match that of established analytical instruments in order to gain acceptance. In this regard, nanomaterials as sensing media offer advantages in sensitivity, preparation of chip-based sensors and construction of electronic nose for selective detection of analytes of interest. This article provides a review of the use of carbon nanotubes in gas and vapor sensing. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Dielectric Sensors Based on Electromagnetic Energy Tunneling

    Directory of Open Access Journals (Sweden)

    Omar Siddiqui

    2015-03-01

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

  4. Membrane-based technologies for biogas separations.

    Science.gov (United States)

    Basu, Subhankar; Khan, Asim L; Cano-Odena, Angels; Liu, Chunqing; Vankelecom, Ivo F J

    2010-02-01

    Over the past two decades, membrane processes have gained a lot of attention for the separation of gases. They have been found to be very suitable for wide scale applications owing to their reasonable cost, good selectivity and easily engineered modules. This critical review primarily focuses on the various aspects of membrane processes related to the separation of biogas, more in specific CO(2) and H(2)S removal from CH(4) and H(2) streams. Considering the limitations of inorganic materials for membranes, the present review will only focus on work done with polymeric materials. An overview on the performance of commercial membranes and lab-made membranes highlighting the problems associated with their applications will be given first. The development studies carried out to enhance the performance of membranes for gas separation will be discussed in the subsequent section. This review has been broadly divided into three sections (i) performance of commercial polymeric membranes (ii) performance of lab-made polymeric membranes and (iii) performance of mixed matrix membranes (MMMs) for gas separations. It will include structural modifications at polymer level, polymer blending, as well as synthesis of mixed matrix membranes, for which addition of silane-coupling agents and selection of suitable fillers will receive special attention. Apart from an overview of the different membrane materials, the study will also highlight the effects of different operating conditions that eventually decide the performance and longevity of membrane applications in gas separations. The discussion will be largely restricted to the studies carried out on polyimide (PI), cellulose acetate (CA), polysulfone (PSf) and polydimethyl siloxane (PDMS) membranes, as these membrane materials have been most widely used for commercial applications. Finally, the most important strategies that would ensure new commercial applications will be discussed (156 references).

  5. Planar potentiometric sensors based on Au and Ag microelectrodes and conducting polymers for flow-cell analysis

    International Nuclear Information System (INIS)

    ToczyIowska, Renata; Pokrop, RafaI; Dybko, Artur; Wroblewski, Wojciech

    2005-01-01

    Back-side contact Au and Ag microelectrodes were used as transducers to construct planar all-solid-state electrodes suitable for flow-through analysis. The microsensors were based on plasticized PVC potassium-selective membranes containing ion-electron conducting polymer-polypyrrole doped with di(2-ethylhexyl) sulfosuccinate. The proposed technique allowed simple construction of microsensors in one step, by membrane solution casting directly on the surface of the planar metallic transducers. The performance of the microsensors based on Au and Ag transducers were determined and compared with planar sensors based on internal electrolyte immobilized in polyHEMA. The addition of the polypyrrole to the membrane composition did not influence on the selectivity, reproducibility and long-term stability of the microsensors but improved their standard potential stability in time in comparison with coated-wire type sensors. Moreover, all-solid-state microsensors based on Au transducers exhibited better signal stability than Ag based sensors

  6. 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.

  7. A smart thermo- and pH-responsive microfiltration membrane based on three-dimensional inverse colloidal crystals.

    Science.gov (United States)

    Yu, Bing; Song, Qianqian; Cong, Hailin; Xu, Xiaodan; Han, Dongwei; Geng, Zhongmin; Zhang, Xiaoyan; Usman, Muhammad

    2017-09-21

    In this paper, a thermo- and pH-responsive microfiltration membrane was prepared based on three-dimensional (3D) inverse colloidal crystals (ICC). To manufacture the smart ICC membrane, the typical thermo-responsive N-isopropylacrylamide (NIPAM) and pH-responsive methacrylic acid (MAA) were polymerized inside silica colloidal crystals. The smart ICC membranes were characterized by SEM, IR and contact angle measurements. Moreover, the permeability of smart microfiltration membrane was carried out by the KCl diffusion tests. The result showed that effective diameter of the polymer ICC membrane can be reversible tuned by temperature and pH. Besides, the functional ICC membrane showed outstanding temperature- and pH-responsive gating property, which was applied to separate particles of different sizes. The savvy environment-responsive gating membranes have potential uses in filtration, separation, purification, sensor and other applications.

  8. Dynamic Response Analysis of Microflow Electrochemical Sensors with Two Types of Elastic Membrane

    Directory of Open Access Journals (Sweden)

    Qiuzhan Zhou

    2016-05-01

    Full Text Available The Molecular Electric Transducer (MET, widely applied for vibration measurement, has excellent sensitivity and dynamic response at low frequencies. The elastic membrane in the MET is a significant factor with an obvious effect on the performance of the MET in the low frequency domain and is the focus of this paper. In simulation experiments, the elastic membrane and the reaction cavity of the MET were analysed in a model based on the multiphysics finite element method. Meanwhile, the effects caused by the elastic membrane elements are verified in this paper. With the numerical simulation and practical experiments, a suitable elastic membrane can be designed for different cavity structures. Thus, the MET can exhibit the best dynamic response characteristics to measure the vibration signals. With the new method presented in this paper, it is possible to develop and optimize the characteristics of the MET effectively, and the dynamic characteristics of the MET can be improved in a thorough and systematic manner.

  9. Metal-organic frameworks based membranes for liquid separation.

    Science.gov (United States)

    Li, Xin; Liu, Yuxin; Wang, Jing; Gascon, Jorge; Li, Jiansheng; Van der Bruggen, Bart

    2017-11-27

    Metal-organic frameworks (MOFs) represent a fascinating class of solid crystalline materials which can be self-assembled in a straightforward manner by the coordination of metal ions or clusters with organic ligands. Owing to their intrinsic porous characteristics, unique chemical versatility and abundant functionalities, MOFs have received substantial attention for diverse industrial applications, including membrane separation. Exciting research activities ranging from fabrication strategies to separation applications of MOF-based membranes have appeared. Inspired by the marvelous achievements of MOF-based membranes in gas separations, liquid separations are also being explored for the purpose of constructing continuous MOFs membranes or MOF-based mixed matrix membranes. Although these are in an emerging stage of vigorous development, most efforts are directed towards improving the liquid separation efficiency with well-designed MOF-based membranes. Therefore, as an increasing trend in membrane separation, the field of MOF-based membranes for liquid separation is highlighted in this review. The criteria for judicious selection of MOFs in fabricating MOF-based membranes are given. Special attention is paid to rational design strategies for MOF-based membranes, along with the latest application progress in the area of liquid separations, such as pervaporation, water treatment, and organic solvent nanofiltration. Moreover, some attractive dual-function applications of MOF-based membranes in the removal of micropollutants, degradation, and antibacterial activity are also reviewed. Finally, we define the remaining challenges and future opportunities in this field. This Tutorial Review provides an overview and outlook for MOF-based membranes for liquid separations. Further development of MOF-based membranes for liquid separation must consider the demands of strict separation standards and environmental safety for industrial application.

  10. Metal–organic frameworks based membranes for liquid separation

    KAUST Repository

    Li, Xin

    2017-11-07

    Metal-organic frameworks (MOFs) represent a fascinating class of solid crystalline materials which can be self-assembled in a straightforward manner by the coordination of metal ions or clusters with organic ligands. Owing to their intrinsic porous characteristics, unique chemical versatility and abundant functionalities, MOFs have received substantial attention for diverse industrial applications, including membrane separation. Exciting research activities ranging from fabrication strategies to separation applications of MOF-based membranes have appeared. Inspired by the marvelous achievements of MOF-based membranes in gas separations, liquid separations are also being explored for the purpose of constructing continuous MOFs membranes or MOF-based mixed matrix membranes. Although these are in an emerging stage of vigorous development, most efforts are directed towards improving the liquid separation efficiency with well-designed MOF-based membranes. Therefore, as an increasing trend in membrane separation, the field of MOF-based membranes for liquid separation is highlighted in this review. The criteria for judicious selection of MOFs in fabricating MOF-based membranes are given. Special attention is paid to rational design strategies for MOF-based membranes, along with the latest application progress in the area of liquid separations, such as pervaporation, water treatment, and organic solvent nanofiltration. Moreover, some attractive dual-function applications of MOF-based membranes in the removal of micropollutants, degradation, and antibacterial activity are also reviewed. Finally, we define the remaining challenges and future opportunities in this field. This Tutorial Review provides an overview and outlook for MOF-based membranes for liquid separations. Further development of MOF-based membranes for liquid separation must consider the demands of strict separation standards and environmental safety for industrial application.

  11. Fleet Protection Using a Small UAV Based IR Sensor

    National Research Council Canada - National Science Library

    Buss, James R; Ax, Jr, George R

    2005-01-01

    A study was performed to define candidate electro-optical and infrared (EO/IR) sensor configurations and assess their potential utility as small UAV-based sensors surveilling a perimeter around surface fleet assets...

  12. Electrochemical sensors based on polyconjugated conducting polymers

    Energy Technology Data Exchange (ETDEWEB)

    Zotti, G. (Ist. di Polarografia ed Elettrochimica Preparativa, Consiglio Nazionale delle Ricerche, Padua (Italy))

    1992-09-01

    An overview of the applications of polyconjugated conducting polymers to electrochemical sensors is given. Gas sensors, ion sensors, and biosensors (non-enzyme and enzyme sensors) are presented and discussed. The role of the polymer as enzyme host and mediator of charge transfer is particularly emphasized in the light of recent results. (orig.).

  13. A general model for membrane-based separation processes

    DEFF Research Database (Denmark)

    Soni, Vipasha; Abildskov, Jens; Jonsson, Gunnar Eigil

    2009-01-01

    behaviour will play an important role. In this paper, modelling of membrane-based processes for separation of gas and liquid mixtures are considered. Two general models, one for membrane-based liquid separation processes (with phase change) and another for membrane-based gas separation are presented....... The separation processes covered are: membrane-based gas separation processes, pervaporation and various types of membrane distillation processes. The specific model for each type of membrane-based process is generated from the two general models by applying the specific system descriptions and the corresponding......A separation process could be defined as a process that transforms a given mixture of chemicals into two or more compositionally distinct end-use products. One way to design these separation processes is to employ a model-based approach, where mathematical models that reliably predict the process...

  14. Photonic Crystal Sensors Based on Porous Silicon

    Directory of Open Access Journals (Sweden)

    Claudia Pacholski

    2013-04-01

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

  15. Photonic Crystal Sensors Based on Porous Silicon

    Science.gov (United States)

    Pacholski, Claudia

    2013-01-01

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

  16. Rapid manufacturing of low-noise membranes for nanopore sensors by trans-chip illumination lithography

    International Nuclear Information System (INIS)

    Janssen, Xander J A; Jonsson, Magnus P; Plesa, Calin; Soni, Gautam V; Dekker, Cees; Dekker, Nynke H

    2012-01-01

    In recent years, the concept of nanopore sensing has matured from a proof-of-principle method to a widespread, versatile technique for the study of biomolecular properties and interactions. While traditional nanopore devices based on a nanopore in a single layer membrane supported on a silicon chip can be rapidly fabricated using standard microfabrication methods, chips with additional insulating layers beyond the membrane region can provide significantly lower noise levels, but at the expense of requiring more costly and time-consuming fabrication steps. Here we present a novel fabrication protocol that overcomes this issue by enabling rapid and reproducible manufacturing of low-noise membranes for nanopore experiments. The fabrication protocol, termed trans-chip illumination lithography, is based on illuminating a membrane-containing wafer from its backside such that a photoresist (applied on the wafer’s top side) is exposed exclusively in the membrane regions. Trans-chip illumination lithography permits the local modification of membrane regions and hence the fabrication of nanopore chips containing locally patterned insulating layers. This is achieved while maintaining a well-defined area containing a single thin membrane for nanopore drilling. The trans-chip illumination lithography method achieves this without relying on separate masks, thereby eliminating time-consuming alignment steps as well as the need for a mask aligner. Using the presented approach, we demonstrate rapid and reproducible fabrication of nanopore chips that contain small (12 μm × 12 μm) free-standing silicon nitride membranes surrounded by insulating layers. The electrical noise characteristics of these nanopore chips are shown to be superior to those of simpler designs without insulating layers and comparable in quality to more complex designs that are more challenging to fabricate. (paper)

  17. Circuit Design of Surface Acoustic Wave Based Micro Force Sensor

    OpenAIRE

    Yuanyuan Li; Wenke Lu; Changchun Zhu; Qinghong Liu; Haoxin Zhang; Chenchao Tang

    2014-01-01

    Pressure sensors are commonly used in industrial production and mechanical system. However, resistance strain, piezoresistive sensor, and ceramic capacitive pressure sensors possess limitations, especially in micro force measurement. A surface acoustic wave (SAW) based micro force sensor is designed in this paper, which is based on the theories of wavelet transform, SAW detection, and pierce oscillator circuits. Using lithium niobate as the basal material, a mathematical model is established ...

  18. Lignin-based membranes for electrolyte transference

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiao; Garcia-Valls, Ricard [Departament d' Enginyeria Quimica, Escola Tecnica Superior d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Paisos Catalans 26, 43007 Tarragona (Spain); Benavente, Juana [Department of Applied Fisics, Faculty of Science, University of Malaga, Malaga (Spain)

    2005-08-18

    Homogeneous PSf-LS membranes are formed by incorporating Lignosulfonate (LS) into the Polysulfone (PSf) network. LS obtained from sulfite pulping process contains sulfonic acid groups that will act as proton transport media. PSf-LS membranes were characterized by reflectance Infrared and scanning electron microscopy. LS showed significant influence on membrane morphology. Higher LS concentration caused a decrease in macrovoid formation and induced larger pores. Precipitation temperature was investigated as influencing parameter. Proton fluxes through PSf-LS membranes were measured by transport experiments. Impedance analysis confirmed that PSf-LS membranes possess ion conductivity. The selected PSf-LS membranes exhibited high selectivity for proton over methanol, which indicates their potential applicability in direct methanol fuel cell (DMFC). (author)

  19. Magnetic enzyme membranes as active elements of electrochemical sensors: specific amino acid enzyme elctrodes.

    Science.gov (United States)

    Calvot, C; Berjonneau, A M; Gellf, G; Thomas, D

    1975-11-15

    The basic principle of the described magnetic enzyme electrodes is a kinetic accumulation of CO2 at the active layer electrode interface. The local pCO2 level is linked to three simultaneous phenomena: substrate diffusion in, enzyme reaction CO2 diffusion out. After a transient state there is a stationary state between the quantity of CO2 produced by the enzyme reaction and the CO2 diffusing from the active membrane to the bulk solution. Continuous determination of free amino acids in biological media is useful in biological processing, fermentation, medicine, pharmaceutical industries and biological research. No methods are presently available for any specific continuous measurement of lysine which is of nutritional importance in protein industrial syntheses; of phenylalanine and tyrosine which have to be monitored in several inborn diseases (phenylketonuria being the most important of them); of arginine and histidine which play a still imperfectly understood part in neurochemistry. The use of decarboxylase bearing membranes as sensors in such measurements could offer several novel advantages: (a) a simple device made of a currently manufactured electrode slightly modified by the use of an enzyme membrane; (b) The absence of any enzymic consumption due to the immobilization and the negligible consumption of substrate during the measurements; (c) The sensitivity which can be sharpened by a systematic study of the membrane parameters; (d) the continuous response of the electrode as long as it is in contact with the substrate solution; (e) the further feasibility as a miniature sensor. The magnetic device introduced allows obviously a convenient use of the enzyme electrode, the active part can be removed and replaced without disturbance for the pCO2 electrode itself. The enzyme electrodes are not only useful at the applied point of view but also at the fundamental point of view by allowing a direct measurement of an intra membrane concentration. The influence of

  20. Ion selective phosphotungestate and beta-cyclodextrin based membrane electrodes for stability-indicating determination of midodrine hydrochloride.

    Science.gov (United States)

    Elzanfaly, Eman S; Zaazaa, Hala E; Merey, Hanan A

    2013-01-01

    This paper reports the construction and evaluation of two ion selective electrodes for the determination midodrine hydrochloride (MD) by direct potentiometry in pure drug substance and in tablet formulations. Precipitation based technique was used for fabrication of the first membrane sensor (sensor 1) using phosphotungestate (PT) and dioctylphthalate (DOP) as cation exchanger and solvent mediator, respectively. beta-cyclodextrin (beta-CD)-based technique with PT as a fixed anionic site in PVC matrix was used for fabrication of the second membrane sensor (sensor 2). The proposed sensors showed fast, stable Nernstian responses of 54 and 56 mV/decade for sensors 1 and 2, respectively, across a relatively wide MD concentration range (1x 10(-4) to 1 x 10(-1) mol/L and 5 x 10(-5) to 1 x 10(-1) mol/L for sensor 1 and 2, respectively) in the pH range of 5-7. Sensor I and sensor 2 can be used for three and two weeks, respectively without any measurable change in sensitivity. The suggested electrodes succeeded to determine intact MD in the presence of up to 10% of its degradation product and displayed good selectivity in presence of common inorganic and organic species.

  1. DIY SENSOR BASED CONTROL FOR HYDROPONIC GARDENNING

    OpenAIRE

    Yuvaraju.M*, Vasanthabalan.V

    2017-01-01

    Hydroponic is the different planting method followed in agriculture. This method is based on water and does not depend on soil. Here the nutrient is added with water and the plants are grown in water. This method need continuous monitoring for growthing and automatic system used here will fulfill the demand. This automatic system control the water pH level, water temperature, surrounding temperature and humidity. In addition it can be monitored remotely using IOT. The sensors used are pH sens...

  2. Task sequencing for sensor-based control

    OpenAIRE

    Mansard, Nicolas; Chaumette, François

    2007-01-01

    International audience; Classical sensor-based approaches tend to constrain all the degrees of freedom of a robot during the execution of a task. In this paper, a new solution is proposed. The key idea is to divide the global full-constraining task into several subtasks, which can be applied or inactivated to take into account potential constraints of the environment. Far from any constraint, the robot moves according to the full task. When it comes closer to a configuration to avoid, a highe...

  3. Optical sensors based on plastic fibers.

    Science.gov (United States)

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

    2012-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Quoc Khanh Dang

    2014-05-01

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

  5. Circuit Design of Surface Acoustic Wave Based Micro Force Sensor

    Directory of Open Access Journals (Sweden)

    Yuanyuan Li

    2014-01-01

    Full Text Available Pressure sensors are commonly used in industrial production and mechanical system. However, resistance strain, piezoresistive sensor, and ceramic capacitive pressure sensors possess limitations, especially in micro force measurement. A surface acoustic wave (SAW based micro force sensor is designed in this paper, which is based on the theories of wavelet transform, SAW detection, and pierce oscillator circuits. Using lithium niobate as the basal material, a mathematical model is established to analyze the frequency, and a peripheral circuit is designed to measure the micro force. The SAW based micro force sensor is tested to show the reasonable design of detection circuit and the stability of frequency and amplitude.

  6. Microfabrication of a Novel Ceramic Pressure Sensor with High Sensitivity Based on Low-Temperature Co-Fired Ceramic (LTCC Technology

    Directory of Open Access Journals (Sweden)

    Chen Li

    2014-06-01

    Full Text Available In this paper, a novel capacitance pressure sensor based on Low-Temperature Co-Fired Ceramic (LTCC technology is proposed for pressure measurement. This approach differs from the traditional fabrication process for a LTCC pressure sensor because a 4J33 iron-nickel-cobalt alloy is applied to avoid the collapse of the cavity and to improve the performance of the sensor. Unlike the traditional LTCC sensor, the sensitive membrane of the proposed sensor is very flat, and the deformation of the sensitivity membrane is smaller. The proposed sensor also demonstrates a greater responsivity, which reaches as high as 13 kHz/kPa in range of 0–100 kPa. During experiments, the newly fabricated sensor, which is only about 6.5 cm2, demonstrated very good performance: the repeatability error, hysteresis error, and nonlinearity of the sensor are about 4.25%, 2.13%, and 1.77%, respectively.

  7. A Triboelectric-Based Artificial Basilar Membrane to Mimic Cochlear Tonotopy.

    Science.gov (United States)

    Jang, Jongmoon; Lee, JangWoo; Jang, Jeong Hun; Choi, Hongsoo

    2016-10-01

    A triboelectric-based artificial basilar membrane (TEABM) can mimic cochlear tonotopy by triboelectrification between Kapton film and aluminum foil. The two films are stacked and clamped to form a beam structure. The TEABM tonotopy is tested using an animal model to verify the feasibility of a self-powered acoustic sensor for a prototype cochlear implant. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Mercury(II) selective sensors based on AlGaN/GaN transistors

    International Nuclear Information System (INIS)

    Asadnia, Mohsen; Myers, Matthew; Akhavan, N.D.; O'Donnell, Kane; Umana-Membreno, Gilberto A.; Mishra, U.K.; Nener, Brett; Baker, Murray; Parish, Giacinta

    2016-01-01

    This work presents the first polymer approach to detect metal ions using AlGaN/GaN transistor-based sensor. The sensor utilised an AlGaN/GaN high electron mobility transistor-type structure by functionalising the gate area with a polyvinyl chloride (PVC) based ion selective membrane. Sensors based on this technology are portable, robust and typically highly sensitive to the target analyte; in this case Hg 2+ . This sensor showed a rapid and stable response when it was introduced to solutions of varying Hg 2+ concentrations. At pH 2.8 in a 10 −2  M KNO 3 ion buffer, a detection limit below 10 −8  M and a linear response range between 10 −8  M-10 −4  M were achieved. This detection limit is an order of magnitude lower than the reported detection limit of 10 −7  M for thioglycolic acid monolayer functionalised AlGaN/GaN HEMT devices. Detection limits of approximately 10 −7  M and 10 −6  M in 10 −2  M Cd(NO 3 ) 2 and 10 −2  M Pb(NO 3 ) 2 ion buffers were also achieved, respectively. Furthermore, we show that the apparent gate response was near-Nernstian under various conditions. X-ray photoelectron spectroscopy (XPS) experiments confirmed that the sensing membrane is reversible after being exposed to Hg 2+ solution and rinsed with deionised water. The success of this study precedes the development of this technology in selectively sensing multiple ions in water with use of the appropriate polymer based membranes on arrays of devices. - Highlights: • This work is the first polymer approach to detect metal ions using AlGaN/GaN transistor-based sensor. • The sensor utilised an AlGaN/GaN transistor by functionalising the gate area with a polyvinyl chloride (PVC) based membrane. • The sensor showed a rapid and linear response between 10 −8 M-10 −4 M for Hg 2+ detection at pH 2.8 in a 10 −2 M KNO 3 ion buffer. • Detection limits of approximately 10 −7 M and 10 −6 M in 10 −2 M Cd(NO 3 ) 2 and 10 −2 M Pb(NO 3 ) 2 ion buffers

  9. Organic Thin-Film Transistor (OTFT-Based Sensors

    Directory of Open Access Journals (Sweden)

    Daniel Elkington

    2014-04-01

    Full Text Available Organic thin film transistors have been a popular research topic in recent decades and have found applications from flexible displays to disposable sensors. In this review, we present an overview of some notable articles reporting sensing applications for organic transistors with a focus on the most recent publications. In particular, we concentrate on three main types of organic transistor-based sensors: biosensors, pressure sensors and “e-nose”/vapour sensors.

  10. Gas Sensors Based on Conducting Polymers

    Directory of Open Access Journals (Sweden)

    Gaoquan Shi

    2007-03-01

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

  11. A novel sensor for monitoring of iron(III) ions based on porphyrins.

    Science.gov (United States)

    Vlascici, Dana; Fagadar-Cosma, Eugenia; Popa, Iuliana; Chiriac, Vlad; Gil-Agusti, Mayte

    2012-01-01

    Three A(3)B porphyrins with mixed carboxy-, phenoxy-, pyridyl-, and dimethoxy-substituent functionalization on the meso-phenyl groups were obtained by multicomponent synthesis, fully characterized and used as ionophores for preparing PVC-based membrane sensors selective to iron(III). The membranes have an ionophore:PVC:plasticizer composition ratio of 1:33:66. Sodium tetraphenylborate was used as additive (20 mol% relative to ionophore). The performance characteristics (linear concentration range, slope and selectivity) of the sensors were investigated. The best results were obtained for the membrane based on 5-(4-carboxyphenyl)-10,15,20-tris(4-phenoxyphenyl)-porphyrin plasticized with bis(2-ethylhexyl)sebacate, in a linear range from 1 × 10(-7)-1 × 10(-1) M with a slope of 21.6 mV/decade. The electrode showed high selectivity with respect to alkaline and heavy metal ions and a response time of 20 s. The influence of pH on the sensor response was studied. The sensor was used for a period of six weeks and the utility has been tested for the quantitative determination of Fe(III) in recovered solutions from spent lithium ion batteries and for the quantitative determination of Fe(III) in tap water samples.

  12. A Novel Sensor for Monitoring of Iron(III) Ions Based on Porphyrins

    Science.gov (United States)

    Vlascici, Dana; Fagadar-Cosma, Eugenia; Popa, Iuliana; Chiriac, Vlad; Gil-Agusti, Mayte

    2012-01-01

    Three A3B porphyrins with mixed carboxy-, phenoxy-, pyridyl-, and dimethoxy-substituent functionalization on the meso-phenyl groups were obtained by multicomponent synthesis, fully characterized and used as ionophores for preparing PVC-based membrane sensors selective to iron(III). The membranes have an ionophore:PVC:plasticizer composition ratio of 1:33:66. Sodium tetraphenylborate was used as additive (20 mol% relative to ionophore). The performance characteristics (linear concentration range, slope and selectivity) of the sensors were investigated. The best results were obtained for the membrane based on 5-(4-carboxyphenyl)-10,15,20-tris(4-phenoxyphenyl)-porphyrin plasticized with bis(2-ethylhexyl)sebacate, in a linear range from 1 × 10−7–1 × 10−1 M with a slope of 21.6 mV/decade. The electrode showed high selectivity with respect to alkaline and heavy metal ions and a response time of 20 s. The influence of pH on the sensor response was studied. The sensor was used for a period of six weeks and the utility has been tested for the quantitative determination of Fe(III) in recovered solutions from spent lithium ion batteries and for the quantitative determination of Fe(III) in tap water samples. PMID:22969395

  13. A Novel Sensor for Monitoring of Iron(III Ions Based on Porphyrins

    Directory of Open Access Journals (Sweden)

    Mayte Gil-Agusti

    2012-06-01

    Full Text Available Three A3B porphyrins with mixed carboxy-, phenoxy-, pyridyl- and dimethoxy-substituent functionalization on the meso-phenyl groups were obtained by multicomponent synthesis, fully characterized and used as ionophores for preparing PVC-based membrane sensors selective to iron(III. The membranes have an ionophore:PVC:plasticizer composition ratio of 1:33:66. Sodium tetraphenylborate was used as additive (20 mol% relative to ionophore. The performance characteristics (linear concentration range, slope and selectivity of the sensors were investigated. The best results were obtained for the membrane based on 5-(4-carboxyphenyl-10,15,20-tris(4-phenoxyphenyl-porphyrin plasticized with bis(2-ethylhexylsebacate, in a linear range from 1 × 10−7–1 × 10−1 M with a slope of 21.6 mV/decade. The electrode showed high selectivity with respect to alkaline and heavy metal ions and a response time of 20 s. The influence of pH on the sensor response was studied. The sensor was used for a period of six weeks and the utility has been tested for the quantitative determination of Fe(III in recovered solutions from spent lithium ion batteries and for the quantitative determination of Fe(III in tap water samples.

  14. Optical stimulator for vision-based sensors

    DEFF Research Database (Denmark)

    Rössler, Dirk; Pedersen, David Arge Klevang; Benn, Mathias

    2014-01-01

    stimulator is used as a test bench to simulate high-precision navigation by different types of camera systems that are used onboard spacecraft, planetary rovers, and for spacecraft rendezvous and proximity maneuvers. Careful hardware design and preoperational calibration of the stimulator result in high......We have developed an optical stimulator system for vision-based sensors. The stimulator is an efficient tool for stimulating a camera during on-ground testing with scenes representative of spacecraft flights. Such scenes include starry sky, planetary objects, and other spacecraft. The optical...... precision and long-term stability. The system can be continuously used over several days. By facilitating a full camera including optics in the loop, the stimulator enables the more realistic simulation of flight maneuvers based on navigation cameras than pure computer simulations or camera stimulations...

  15. Nanofibers and thin films as a selective membrane for sensors and microTAS

    International Nuclear Information System (INIS)

    Silva, A N R da; Silva, M L P da; Fachini, E R

    2013-01-01

    A composite material of PAN (polyacrylonitrile), starch granules and dimethylformamide as solvent was used as a selective membrane for volatile organic compounds (VOCs) in gaseous phase. This composite was produced as a thin film obtained by spin-casting and as a fiber mat produced by electrospinning. The fiber mat was tested for adsorption of VOCs and water. Characterization used microscopy (electron scanning and optical) in order to evaluate the fiber morphology and the starch incorporation in the PAN matrix. Infrared spectroscopy was intended to determine the starch presence. Relative viscosity of the starch/PAN suspensions was measured in order to provide a model of composite fiber formation. Quartz crystal microbalance experiments determined VOCs and water adsorption. Fibers incorporated the starch granules, making the composite sensible to water; but VOCs were not detected. Therefore, the composite was found to be a good choice as selective barrier on sensors or microTAS protection purposes.

  16. Single conducting polymer nanowire based conductometric sensors

    Science.gov (United States)

    Bangar, Mangesh Ashok

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

  17. Optical Fiber Sensors Based on Nanoparticle-Embedded Coatings

    Directory of Open Access Journals (Sweden)

    Aitor Urrutia

    2015-01-01

    Full Text Available The use of nanoparticles (NPs in scientific applications has attracted the attention of many researchers in the last few years. The use of NPs can help researchers to tune the physical characteristics of the sensing coating (thickness, roughness, specific area, refractive index, etc. leading to enhanced sensors with response time or sensitivity better than traditional sensing coatings. Additionally, NPs also offer other special properties that depend on their nanometric size, and this is also a source of new sensing applications. This review focuses on the current status of research in the use of NPs within coatings in optical fiber sensing. Most used sensing principles in fiber optics are briefly described and classified into several groups: absorbance-based sensors, interferometric sensors, fluorescence-based sensors, fiber grating sensors, and resonance-based sensors, among others. For each sensor group, specific examples of the utilization of NP-embedded coatings in their sensing structure are reported.

  18. Chemical sensors based on surface charge transfer

    Science.gov (United States)

    Mohtasebi, Amirmasoud; Kruse, Peter

    2018-02-01

    The focus of this review is an introduction to chemiresistive chemical sensors. The general concept of chemical sensors is briefly introduced, followed by different architectures of chemiresistive sensors and relevant materials. For several of the most common systems, the fabrication of the active materials used in such sensors and their properties are discussed. Furthermore, the sensing mechanism, advantages, and limitations of each group of chemiresistive sensors are briefly elaborated. Compared to electrochemical sensors, chemiresistive sensors have the key advantage of a simpler geometry, eliminating the need for a reference electrode. The performance of bulk chemiresistors can be improved upon by using freestanding ultra-thin films (nanomaterials) or field effect geometries. Both of those concepts have also been combined in a gateless geometry, where charge transport though a percolation network of nanomaterials is modulated via adsorbate doping.

  19. Two Dimensional Array of Piezoresistive Nanomechanical Membrane-Type Surface Stress Sensor (MSS with Improved Sensitivity

    Directory of Open Access Journals (Sweden)

    Nico F. de Rooij

    2012-11-01

    Full Text Available We present a new generation of piezoresistive nanomechanical Membrane-type Surface stress Sensor (MSS chips, which consist of a two dimensional array of MSS on a single chip. The implementation of several optimization techniques in the design and microfabrication improved the piezoresistive sensitivity by 3~4 times compared to the first generation MSS chip, resulting in a sensitivity about ~100 times better than a standard cantilever-type sensor and a few times better than optical read-out methods in terms of experimental signal-to-noise ratio. Since the integrated piezoresistive read-out of the MSS can meet practical requirements, such as compactness and not requiring bulky and expensive peripheral devices, the MSS is a promising transducer for nanomechanical sensing in the rapidly growing application fields in medicine, biology, security, and the environment. Specifically, its system compactness due to the integrated piezoresistive sensing makes the MSS concept attractive for the instruments used in mobile applications. In addition, the MSS can operate in opaque liquids, such as blood, where optical read-out techniques cannot be applied.

  20. Styrene-Based Copolymer for Polymer Membrane Modifications

    OpenAIRE

    Harsha Srivastava; Harshad Lade; Diby Paul; G. Arthanareeswaran; Ji Hyang Kweon

    2016-01-01

    Poly(vinylidene fluoride) (PVDF) was modified with a styrene-based copolymer. The crystalline behavior, phase, thermal stability, and surface morphology of the modified membranes were analyzed. The membrane surface roughness showed a strong dependence on the styrene-acrylonitrile content and was reduced to 34% for a PVDF/styrene-acrylonitrile blend membrane with a 40/60 ratio. The thermal and crystalline behavior confirmed the blend miscibility of both polymers. It was observed in X-ray diffr...

  1. Novel thermal efficiency-based model for determination of thermal conductivity of membrane distillation membranes

    International Nuclear Information System (INIS)

    Vanneste, Johan; Bush, John A.; Hickenbottom, Kerri L.; Marks, Christopher A.; Jassby, David

    2017-01-01

    Development and selection of membranes for membrane distillation (MD) could be accelerated if all performance-determining characteristics of the membrane could be obtained during MD operation without the need to recur to specialized or cumbersome porosity or thermal conductivity measurement techniques. By redefining the thermal efficiency, the Schofield method could be adapted to describe the flux without prior knowledge of membrane porosity, thickness, or thermal conductivity. A total of 17 commercially available membranes were analyzed in terms of flux and thermal efficiency to assess their suitability for application in MD. The thermal-efficiency based model described the flux with an average %RMSE of 4.5%, which was in the same range as the standard deviation on the measured flux. The redefinition of the thermal efficiency also enabled MD to be used as a novel thermal conductivity measurement device for thin porous hydrophobic films that cannot be measured with the conventional laser flash diffusivity technique.

  2. Zirconia-based solid state chemical gas sensors

    CERN Document Server

    Zhuiykov, S

    2000-01-01

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

  3. Vehicle Fault Diagnose Based on Smart Sensor

    Science.gov (United States)

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

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

  4. Carbon-Nanotube-Based Chemical Gas Sensor

    Science.gov (United States)

    Kaul, Arunpama B.

    2010-01-01

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

  5. Physiological sensor signals classification for healthcare using sensor data fusion and case-based reasoning.

    Science.gov (United States)

    Begum, Shahina; Barua, Shaibal; Ahmed, Mobyen Uddin

    2014-07-03

    Today, clinicians often do diagnosis and classification of diseases based on information collected from several physiological sensor signals. However, sensor signal could easily be vulnerable to uncertain noises or interferences and due to large individual variations sensitivity to different physiological sensors could also vary. Therefore, multiple sensor signal fusion is valuable to provide more robust and reliable decision. This paper demonstrates a physiological sensor signal classification approach using sensor signal fusion and case-based reasoning. The proposed approach has been evaluated to classify Stressed or Relaxed individuals using sensor data fusion. Physiological sensor signals i.e., Heart Rate (HR), Finger Temperature (FT), Respiration Rate (RR), Carbon dioxide (CO2) and Oxygen Saturation (SpO2) are collected during the data collection phase. Here, sensor fusion has been done in two different ways: (i) decision-level fusion using features extracted through traditional approaches; and (ii) data-level fusion using features extracted by means of Multivariate Multiscale Entropy (MMSE). Case-Based Reasoning (CBR) is applied for the classification of the signals. The experimental result shows that the proposed system could classify Stressed or Relaxed individual 87.5% accurately compare to an expert in the domain. So, it shows promising result in the psychophysiological domain and could be possible to adapt this approach to other relevant healthcare systems.

  6. Ultrafiltration and Nanofiltration Multilayer Membranes Based on Cellulose

    KAUST Repository

    Livazovic, Sara

    2016-06-09

    Membrane processes are considered energy-efficient for water desalination and treatment. However most membranes are based on polymers prepared from fossil petrochemical sources. The development of multilayer membranes for nanofiltration and ultrafiltration, with thin selective layers of naturally available cellulose, has been hampered by the availability of non-aggressive solvents. We propose the manufacture of cellulose membranes based on two approaches: (i) silylation, coating from solutions in tetrahydrofuran, followed by solvent evaporation and cellulose regeneration by acid treatment; (ii) casting from solution in 1-ethyl-3-methylimidazolum acetate ([C2mim]OAc), an ionic liquid, followed by phase inversion in water. In the search for less harsh, greener membrane manufacture, the combination of cellulose and ionic liquid is of high interest. Due to the abundance of OH groups and hydrophilicity, cellulose-based membranes have high permeability and low fouling tendency. Membrane fouling is one of the biggest challenges in membrane industry and technology. Accumulation and deposition of foulants onto the surface reduce membrane efficiency and requires harsh chemical cleaning, therefore increasing the cost of maintenance and replacement. In this work the resistance of cellulose 5 membranes towards model organic foulants such as Suwanee River Humic Acid (SRHA) and crude oil have been investigated. Cellulose membrane was tested in this work for oil-water (o/w) separation and exhibited practically 100 % oil rejection with good flux recovery ratio and membrane resistivity. The influence of anionic, cationic and ionic surfactant as well as pH and crude oil concentration on oil separation was investigated, giving a valuable insight in experimental and operational planning.

  7. Sensor-based demand controlled ventilation

    Energy Technology Data Exchange (ETDEWEB)

    De Almeida, A.T. [Universidade de Coimbra (Portugal). Dep. Eng. Electrotecnica; Fisk, W.J. [Lawrence Berkeley National Lab., CA (United States)

    1997-07-01

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

  8. Structural health monitoring system for bridges based on skin-like sensor

    Science.gov (United States)

    Loupos, Konstantinos; Damigos, Yannis; Amditis, Angelos; Gerhard, Reimund; Rychkov, Dmitry; Wirges, Werner; Schulze, Manuel; Lenas, Sotiris-Angelos; Chatziandreoglou, Christos; Malliou, Christina M.; Tsaoussidis, Vassilis; Brady, Ken; Frankenstein, Bernd

    2017-09-01

    Structural health monitoring activities are of primal importance for managing transport infrastructure, however most SHM methodologies are based on point-based sensors that have limitations in terms of their spatial positioning requirements, cost of development and measurement range. This paper describes the progress on the SENSKIN EC project whose objective is to develop a dielectric-elastomer and micro-electronics-based sensor, formed from a large highly extensible capacitance sensing membrane supported by advanced microelectronic circuitry, for monitoring transport infrastructure bridges. Such a sensor could provide spatial measurements of strain in excess of 10%. The actual sensor along with the data acquisition module, the communication module and power electronics are all integrated into a compact unit, the SENSKIN device, which is energy-efficient, requires simple signal processing and it is easy to install over various surface types. In terms of communication, SENSKIN devices interact with each other to form the SENSKIN system; a fully distributed and autonomous wireless sensor network that is able to self-monitor. SENSKIN system utilizes Delay-/Disruption-Tolerant Networking technologies to ensure that the strain measurements will be received by the base station even under extreme conditions where normal communications are disrupted. This paper describes the architecture of the SENSKIN system and the development and testing of the first SENSKIN prototype sensor, the data acquisition system, and the communication system.

  9. Highly selective thiocyanate optochemical sensor based on manganese(III)-salophen ionophore

    International Nuclear Information System (INIS)

    Abdel-Haleem, Fatehy M.; Rizk, Mahmoud S.

    2017-01-01

    We report on the development of optochemical sensor based on Mn(III)-salophen ionophore. The sensor was prepared by embedding the ionophore in a plasticized poly (vinyl chloride) impregnated with the chromoionophore ETH7075. Optical response to thiocyanate occurred due to thiocyanate extraction into the polymer via formation of strong complex with the ionophore and simultaneous protonation of the indicator dye yielding the optical response at 545 nm. The developed optochemical sensor exhibited high selectivity for thiocyanate over other anions including the most lipophilic species such as salicylate and perchlorate. For instance, the optical selectivity coefficients, logK SCN,anion opt , were as follow: ClO 4 − = − 5.8; Sal − = − 4.0; NO 3 − ˂ − 6. Further, the thiocyanate optical selectivity obtained using the present optochemical sensor was greatly enhanced in comparison with that obtained using an anion-exchanger based sensor. Also, the optimized optochemical sensor exhibited micro-molar detection limit with 2 min response time at pH 4.5 using acetate buffer. The reversibility of the optimized sensor was poor due to strong ligation of the thiocyanate to the central Metal ion, log K = 14.1, which can be overcome by soaking the optode in sodium hydroxide followed by soaking in buffer solution. The developed sensor was utilized successfully for the determination of thiocyanate in human saliva and in spiked saliva samples. - Highlights: • Preparation of different optodes using different compositions • Mechanism depends on co-extraction of thiocyanate and protons to membrane. • Sensor showed excellent selectivity. • Sensor could be applied for thiocyanate determination in real saliva.

  10. Proton Conductivity and Operational Features Of PBI-Based Membranes

    DEFF Research Database (Denmark)

    Qingfeng, Li; Jensen, Jens Oluf; Precht Noyé, Pernille

    2005-01-01

    As an approach to high temperature operation of PEMFCs, acid-doped PBI membranes are under active development. The membrane exhibits high proton conductivity under low water contents at temperatures up to 200°C. Mechanisms of proton conduction for the membranes have been proposed. Based on the me...... on the membranes fuel cell tests have been demonstrated. Operating features of the PBI cell include no humidification, high CO tolerance, better heat utilization and possible integration with fuel processing units. Issues for further development are also discussed....

  11. A novel membrane sensor controls the localization and ArfGEF activity of bacterial RalF.

    Directory of Open Access Journals (Sweden)

    Marcia Folly-Klan

    Full Text Available The intracellular bacterial pathogen Legionella pneumophila (Lp evades destruction in macrophages by camouflaging in a specialized organelle, the Legionella-containing vacuole (LCV, where it replicates. The LCV maturates by incorporating ER vesicles, which are diverted by effectors that Lp injects to take control of host cell membrane transport processes. One of these effectors, RalF, recruits the trafficking small GTPase Arf1 to the LCV. LpRalF has a Sec7 domain related to host ArfGEFs, followed by a capping domain that intimately associates with the Sec7 domain to inhibit GEF activity. How RalF is activated to function as a LCV-specific ArfGEF is unknown. We combined the reconstitution of Arf activation on artificial membranes with cellular expression and Lp infection assays, to analyze how auto-inhibition is relieved for LpRalF to function in vivo. We find that membranes activate LpRalF by about 1000 fold, and identify the membrane-binding region as the region that inhibits the Sec7 active site. It is enriched in aromatic and positively charged residues, which establish a membrane sensor to control the GEF activity in accordance with specific lipid environments. A similar mechanism of activation is found in RalF from Rickettsia prowazekii (Rp, with a different aromatic/charged residues ratio that results in divergent membrane preferences. The membrane sensor is the primary determinant of the localization of LpRalF on the LCV, and drives the timing of Arf activation during infection. Finally, we identify a conserved motif in the capping domain, remote from the membrane sensor, which is critical for RalF activity presumably by organizing its active conformation. These data demonstrate that RalF proteins are regulated by a membrane sensor that functions as a binary switch to derepress ArfGEF activity when RalF encounters a favorable lipid environment, thus establishing a regulatory paradigm to ensure that Arf GTPases are efficiently activated at

  12. Durability Issues of High Temperature Proton Exchange Membrane Fuel Cells Based on Acid Doped Polybenzimidazole Membranes

    DEFF Research Database (Denmark)

    To achieve high temperature operation of proton exchange membrane fuel cells (PEMFC), preferably under ambient pressure, phosphoric acid doped polybenzimidazole (PBI) membrane represents an effective approach, which in recent years has motivated extensive research activities with great progress....... As a critical concern, issues of long term durability of PBI based fuel cells are addressed in this talk, including oxidative degradation of the polymer, mechanical failures of the membrane, acid leaching out, corrosion of carbon support and sintering of catalysts particles. Excellent polymer durability has...

  13. NMR-based screening of membrane protein ligands

    NARCIS (Netherlands)

    Yanamala, Naveena; Dutta, Arpana; Beck, Barbara; Van Fleet, Bart; Hay, Kelly; Yazbak, Ahmad; Ishima, Rieko; Doemling, Alexander; Klein-Seetharaman, Judith

    2010-01-01

    Membrane proteins pose problems for the application of NMR-based ligand-screening methods because of the need to maintain the proteins in a membrane mimetic environment such as detergent micelles: they add to the molecular weight of the protein, increase the viscosity of the solution, interact with

  14. Co2+-selective membrane electrode based on the Schiff Base NADS.

    Science.gov (United States)

    Mashhadizadeh, Mohammad Hossein; Sheikhshoaie, Iran

    2003-03-01

    A new PVC membrane electrode for cobalt(II) ions based on a recently synthesized Schiff base of 5-((4-nitrophenyl)azo)- N-(2',4'-dimethoxyphenyl)salicylaldimine is reported. The electrode exhibits a Nernstian response for Co(2+) ions over a wide concentration range (9.0 x 10(-7)-1.0 x 10(-2) M) with a slope of 29(+/-1). The limit of detection is 8.0 x 10(-7) M. The proposed sensor revealed good selectivities over a wide variety of other cations including hard and soft metals. This electrode could be used in a pH range of 3.5-6.0. It was used as an indicator electrode in potentiometric titrations of cobalt(II) ions and can be used in the direct determination of Co(2+) in aqueous solutions.

  15. Eddy current probe development based on a magnetic sensor array

    International Nuclear Information System (INIS)

    Vacher, F.

    2007-06-01

    This research deals with in the study of the use of innovating magnetic sensors in eddy current non destructive inspection. The author reports an analysis survey of magnetic sensor performances. This survey enables the selection of magnetic sensor technologies used in non destructive inspection. He presents the state-of-the-art of eddy current probes exploiting the qualities of innovating magnetic sensors, and describes the methods enabling the use of these magnetic sensors in non destructive testing. Two main applications of innovating magnetic sensors are identified: the detection of very small defects by means of magneto-resistive sensors, and the detection of deep defects by means of giant magneto-impedances. Based on the use of modelling, optimization, signal processing tools, probes are manufactured for these both applications

  16. Resistive humidity sensor based on vanadium complex films

    Science.gov (United States)

    Karimov, Kh. S.; Saleem, M.; Mahroof-Tahir, M.; Akram, R.; Saeed Chanee, M. T.; Niaz, A. K.

    2014-09-01

    A resistive-type relative humidity (RH) sensor based on vanadium complex (VO2(3-fl)) film is reported in this study. Gold electrodes were deposited on the glass substrates in a co-planar structure. A thin film of vanadium complex was coated as a humidity-sensing material on the top of the pre-patterned electrodes. The humidity-sensing principle of the sensor was based on the conductivity change of coated sensing element upon adsorption/desorption of water vapor. The resistance of the humidity sensor measured at 1 kHz decreased linearly with increasing the humidity in the range of 35%-70% RH. The overall resistance of the sensor decreases 11 times. An equivalent circuit for the VO2(3-fl) based resistive-type humidity sensor was developed. The properties of the sensor studied in this work make it beneficial for use in the instruments for environmental monitoring of humidity.

  17. Applications of FBG-based sensors to ground stability monitoring

    Directory of Open Access Journals (Sweden)

    An-Bin Huang

    2016-08-01

    Full Text Available Over the past few decades, many optical fiber sensing techniques have been developed. Among these available sensing methods, optical fiber Bragg grating (FBG is probably the most popular one. With its unique capabilities, FBG-based geotechnical sensors can be used as a sensor array for distributive (profile measurements, deployed under water (submersible, for localized high resolution and/or differential measurements. The authors have developed a series of FBG-based transducers that include inclination, linear displacement and gauge/differential pore pressure sensors. Techniques that involve the field deployment of FBG inclination, extension and pore-pressure sensor arrays for automated slope stability and ground subsidence monitoring have been developed. The paper provides a background of FBG and the design concepts behind the FBG-based field monitoring sensors. Cases of field monitoring using the FBG sensor arrays are presented, and their practical implications are discussed.

  18. New Development of Membrane Base Optoelectronic Devices

    Directory of Open Access Journals (Sweden)

    Leon Hamui

    2017-12-01

    Full Text Available It is known that one factor that affects the operation of optoelectronic devices is the effective protection of the semiconductor materials against environmental conditions. The permeation of atmospheric oxygen and water molecules into the device structure induces degradation of the electrodes and the semiconductor. As a result, in this communication we report the fabrication of semiconductor membranes consisting of Magnesium Phthalocyanine-allene (MgPc-allene particles dispersed in Nylon 11 films. These membranes combine polymer properties with organic semiconductors properties and also provide a barrier effect for the atmospheric gas molecules. They were prepared by high vacuum evaporation and followed by thermal relaxation technique. For the characterization of the obtained membranes, Fourier-transform infrared spectroscopy (FT-IR, scanning electron microscopy (SEM, and energy dispersive spectroscopy (EDS were used to determine the chemical and microstructural properties. UV-ViS, null ellipsometry, and visible photoluminescence (PL at room temperature were used to characterize the optoelectronic properties. These results were compared with those obtained for the organic semiconductors: MgPc-allene thin films. Additionally, semiconductor membranes devices have been prepared, and a study of the device electronic transport properties was conducted by measuring electrical current density-voltage (J-V characteristics by four point probes with different wavelengths. The resistance properties against different environmental molecules are enhanced, maintaining their semiconductor functionality that makes them candidates for optoelectronic applications.

  19. Development of Multichannel Artificial Lipid-Polymer Membrane Sensor for Phytomedicine Application

    Directory of Open Access Journals (Sweden)

    Ali Yeon Md Shakaff

    2006-10-01

    Full Text Available Quality control of herbal medicines remain a challenging issue towardsintegrating phytomedicine into the primary health care system. As medicinal plants is acomplicated system of mixtures, a rapid and cost-effective evaluation method tocharacterize the chemical fingerprint of the plant without performing laborious samplepreparation procedure is reported. A novel research methodology based on an in-housefabricated multichannel sensor incorporating an array of artificial lipid-polymer membraneas a fingerprinting device for quality evaluation of a highly sought after herbal medicine inthe Asean Region namely Eurycoma longifolia (Tongkat Ali. The sensor array is based onthe principle of the bioelectronic tongue that mimics the human gustatory system throughthe incorporation of artificial lipid material as sensing element. The eight non-specificsensors have partially overlapping selectivity and cross-sensitivity towards the targetedanalyte. Hence, electrical potential response represented by radar plot is used to characterizeextracts from different parts of plant, age, batch-to-batch variation and mode of extraction ofE. longifolia through the obtained potentiometric fingerprint profile. Classification modelwas also developed classifying various E. longifolia extracts with the aid of chemometricpattern recognition tools namely hierarchical cluster analysis (HCA and principalcomponent analysis (PCA. The sensor seems to be a promising analytical device for qualitycontrol based on potentiometric fingerprint analysis of phytomedicine.

  20. CMOS-based Integrated Wavefront Sensor

    NARCIS (Netherlands)

    De Lima Monteiro, D.W.

    2002-01-01

    This thesis addresses the design, implementation and performance of an integrated Hartmann-Shack wavefront sensor suitable for real-time operation and compatible with a standard technology. A wavefront sensor can be used for the detection of distortions in the profile of a light beam or of an

  1. Calculating Traffic based on Road Sensor Data

    NARCIS (Netherlands)

    Bisseling, Rob; Gao, Fengnan; Hafkenscheid, Patrick; Idema, Reijer; Jetka, Tomasz; Guerra Ones, Valia; Rata, Debanshu; Sikora, Monika

    2014-01-01

    Road sensors gather a lot of statistical data about traffic. In this paper, we discuss how a measure for the amount of traffic on the roads can be derived from this data, such that the measure is independent of the number and placement of sensors, and the calculations can be performed quickly for

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

    Science.gov (United States)

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

    2016-01-01

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

  3. Styrene-Based Copolymer for Polymer Membrane Modifications

    Directory of Open Access Journals (Sweden)

    Harsha Srivastava

    2016-05-01

    Full Text Available Poly(vinylidene fluoride (PVDF was modified with a styrene-based copolymer. The crystalline behavior, phase, thermal stability, and surface morphology of the modified membranes were analyzed. The membrane surface roughness showed a strong dependence on the styrene-acrylonitrile content and was reduced to 34% for a PVDF/styrene-acrylonitrile blend membrane with a 40/60 ratio. The thermal and crystalline behavior confirmed the blend miscibility of both polymers. It was observed in X-ray diffraction (XRD experiments that the modified PVDF membranes show a drastic reduction in their crystallinity. The neat PVDF membrane has the highest degradation rate, which decreased with the addition of the styrene-based copolymer.

  4. Humidity detection using chitosan film based sensor

    Science.gov (United States)

    Nasution, T. I.; Nainggolan, I.; Dalimunthe, D.; Balyan, M.; Cuana, R.; Khanifah, S.

    2018-02-01

    A humidity sensor made of the natural polymer chitosan has been successfully fabricated in the film form by a solution casting method. Humidity testing was performed by placing a chitosan film sensor in a cooling machine room, model KT-2000 Ahu. The testing results showed that the output voltage values of chitosan film sensor increased with the increase in humidity percentage. For the increase in humidity percentage from 30 to 90% showed that the output voltage of chitosan film sensor increased from 32.19 to 138.75 mV. It was also found that the sensor evidenced good repeatability and stability during the testing. Therefore, chitosan has a great potential to be used as new sensing material for the humidity detection of which was cheaper and environmentally friendly.

  5. A MEMS SOI-based piezoresistive fluid flow sensor

    Science.gov (United States)

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

    2018-02-01

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

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

    Science.gov (United States)

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

    2018-02-01

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

  7. Chemical sensors based on quantum cascade lasers

    Science.gov (United States)

    Tittel, Frank K.; Kosterev, Anatoliy A.; Rochat, Michel; Beck, Mattias; Faist, Jerome

    2002-09-01

    There is an increasing need in many chemical sensing applications ranging from industrial process control to environmental science and medical diagnostics for fast, sensitive, and selective gas detection based on laser spectroscopy. The recent availability of novel pulsed and cw quantum cascade distributed feedback (QC-DFB) lasers as mid-infrared spectroscopic sources address this need. A number of spectroscopic techniques have been demonstrated. For example, the authors have employed QC-DFB lasers for the monitoring and quantification of several trace gases and isotopic species in ambient air at ppmv and ppbv levels by means of direct absorption, wavelength modulation, cavity enhanced and cavity ringdown spectroscopy. In this work, pulsed thermoelectrically cooled QC-DFB lasers operating at ~15.6 μm were characterized for spectroscopic gas sensing applications. A new method for wavelength scanning based on the repetition rate modulation was developed. A non-wavelength-selective pyroelectric detector was incorporated in the gas sensor giving an advantage of room-temperature operation and low cost. Absorption lines of CO2 and H2O were observed in ambient air providing information about the concentration of these species.

  8. All-plastic fiber-based pressure sensor

    DEFF Research Database (Denmark)

    Bundalo, Ivan-Lazar; Lwin, Richard; Leon-Saval, Sergio

    2016-01-01

    We present a feasibility study and a prototype of an all-plastic fiber-based pressure sensor. The sensor is based on long period gratings inscribed for the first time to the best of our knowledge by a CO2 laser in polymethyl methacrylate (PMMA) microstructured fibers and coupled to a pod......-like transducer that converts pressure to strain. The sensor prototype was characterized for pressures up to 150 mbars, and various parameters related to its construction were also characterized in order to enhance sensitivity. We consider this sensor in the context of future applications in endoscopic pressure...

  9. MEMS-based thermoelectric infrared sensors: A review

    Science.gov (United States)

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

    2017-12-01

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

  10. Resource Discovery in Activity-Based Sensor Networks

    DEFF Research Database (Denmark)

    Bucur, Doina; Bardram, Jakob

    This paper proposes a service discovery protocol for sensor networks that is specifically tailored for use in humancentered pervasive environments. It uses the high-level concept of computational activities (as logical bundles of data and resources) to give sensors in Activity-Based Sensor Networks...... (ABSNs) knowledge about their usage even at the network layer. ABSN redesigns classical network-level service discovery protocols to include and use this logical structuring of the network for a more practically applicable service discovery scheme. Noting that in practical settings activity-based sensor...

  11. Involvement of outer membrane proteins and peroxide-sensor genes in Burkholderia cepacia resistance to isothiazolone.

    Science.gov (United States)

    Zhou, Gang; Shi, Qing-shan; Ouyang, You-sheng; Chen, Yi-ben

    2014-04-01

    Isothiazolones are used as preservatives in various modern industrial products. Although microorganisms that exhibit resistance towards these biocides have been identified, the underlying resistance mechanisms are still unclear. Therefore, we investigated the resistance properties of the following Burkholderia cepacia strains to Kathon (a representative of isothiazolones): a wild-type (WT) strain; a laboratory resistance strain (BC-IR) induced from WT; and an isolated strain (BC-327) screened from industrial contamination samples. The bacterial cell structure was disrupted by 50 μg ml⁻¹ Kathon treatment. BC-IR and BC-327 did not display resistance in the presence of 1 ml L⁻¹ Tween 80, 1 ml L⁻¹ Triton X-100, 0.1 % sodium dodecyl sulfate or 1 mmol L⁻¹ EDTA-2Na. Additionally, BC-IR and BC-327 exhibited lower relative conductivity from 10 to 180 min. The types as well as the levels of outer-membrane proteins (OMPs) were altered among WT, BC-IR and BC-327. Finally, the two Kathon-resistance strains BC-IR and BC-327 presented higher resistance capacity to H₂O₂. We measured the levels of peroxide-sensor genes and observed that the transcriptional activator oxyR, superoxide dismutase sod1, sod2, catalase cat1 and cat3 were all up-regulated under oxidative conditions for all strains. Taken together, OMPs and peroxide-sensor genes in B. cepacia contributed to isothiazolone resistance; However, the laboratory strain BC-IR exhibited a different resistance mechanism and properties compared to the isolated strain BC-327.

  12. Lamb Waves Propagation along 3C-SiC/AlN Membranes for Application in Temperature-Compensated, High-Sensitivity Gravimetric Sensors

    Directory of Open Access Journals (Sweden)

    Cinzia Caliendo

    2013-01-01

    Full Text Available The propagation of the fundamental quasi-symmetric Lamb mode S0 travelling along 3C-SiC/c-AlN composite plates is theoretically studied with respect to the AlN and SiC film thickness, the acoustic wave propagation direction and the electrical boundary conditions. The temperature effects on the phase velocity have been considered for four AlN/SiC-based electroacoustic coupling configurations, specifically addressing the design of temperature-compensated, enhanced-coupling, GHz-range electroacoustic devices. The gravimetric sensitivity and resolution of the four temperature-stable SiC/AlN composite structures are theoretically investigated with respect to both the AlN and SiC sensing surface. The SiC/AlN-based sensor performances are compared to those of surface acoustic waves and Lamb S0 mode mass sensors implemented on bulk conventional piezoelectric materials and on thin suspended membranes.

  13. Lamb waves propagation along 3C-SiC/AlN membranes for application in temperature-compensated, high-sensitivity gravimetric sensors.

    Science.gov (United States)

    Caliendo, Cinzia; D'Amico, Arnaldo; Lo Castro, Fabio

    2013-01-02

    The propagation of the fundamental quasi-symmetric Lamb mode S(0) travelling along 3C-SiC/c-AlN composite plates is theoretically studied with respect to the AlN and SiC film thickness, the acoustic wave propagation direction and the electrical boundary conditions. The temperature effects on the phase velocity have been considered for four AlN/SiC-based electroacoustic coupling configurations, specifically addressing the design of temperature-compensated, enhanced-coupling, GHz-range electroacoustic devices. The gravimetric sensitivity and resolution of the four temperature-stable SiC/AlN composite structures are theoretically investigated with respect to both the AlN and SiC sensing surface. The SiC/AlN-based sensor performances are compared to those of surface acoustic waves and Lamb S(0) mode mass sensors implemented on bulk conventional piezoelectric materials and on thin suspended membranes.

  14. A Novel Ion - selective Polymeric Membrane Sensor for Determining Thallium(I) With High Selectivity

    International Nuclear Information System (INIS)

    Kassim, Anuar; Rezayi, Majid; Ahmadzadeh, Saeid; Yusof, Noor Azah; Tee, Tan Wee; Abdullah, Abd Halim; Rounaghi, Gholamhossein; Mohajeri, Masoomeh; Heng, Lee Yook

    2011-01-01

    Thallium is a toxic metal that introduced into the environment mainly as a waste from the production of zinc, cadmium, and lead and by combustion of coal. Thallium causes gastrointestinal irritation and nerve damage when people are exposed to it for relatively short period of time. For long term, thallium has the potential to cause the following effects: change in blood chemistry, damage to liver, kidney, intestinal and testicular tissue, and hair loss. In this work a membrane was prepared by use of 4'-nitrobenzo -18-crown-6 (4'NB18C6) as an ion carrier, polyvinylchloride (PVC) as a matrix, and diocthylphetalate (DOP) as a plasticizer for making an ion selective electrode for measurement of Tl + cation in solutions. The amount of 4'-nitrobenzo-18C6 and polyvinylchloride were optimized in the preparation of the membrane. The response of the electrode was Nernstian within the concentration range 1.0 x 10 -8 to 1.0 x 10 -1 M. This sensor displays a drift in Nernstian response for this cation with increasing the amount of ionophore and decreasing the amount of polyvinylchloride.The results of potentiometric measurements showed that, this electrode also responses to Cu 2+ Ni 2+ and Pb 2+ cations, but the electrode has a wider dynamic range and a lower detection limit to Tl + cation. The effects of various parameters such as pH, different cations interferences, effect of the amount of ionophore and polyvinylchloride and time on response of the coated ion selective electrode were investigated. Finally the constructed electrode was used in complexometric and precipitation titrations of Tl + cation with EDTA and KBr, respectively. The response of the fabricated electrode at concentration range from 1.0 x 10 -8 to 1.0 x 10 -1 M is linear with a Nernstian slope of 57.27 mV.

  15. A Novel Ion - selective Polymeric Membrane Sensor for Determining Thallium(I) With High Selectivity

    Science.gov (United States)

    Kassim, Anuar; Rezayi, Majid; Ahmadzadeh, Saeid; Rounaghi, Gholamhossein; Mohajeri, Masoomeh; Azah Yusof, Noor; Tee, Tan Wee; Yook Heng, Lee; Halim Abdullah, Abd

    2011-02-01

    Thallium is a toxic metal that introduced into the environment mainly as a waste from the production of zinc, cadmium, and lead and by combustion of coal. Thallium causes gastrointestinal irritation and nerve damage when people are exposed to it for relatively short period of time. For long term, thallium has the potential to cause the following effects: change in blood chemistry, damage to liver, kidney, intestinal and testicular tissue, and hair loss. In this work a membrane was prepared by use of 4'-nitrobenzo -18-crown-6 (4'NB18C6) as an ion carrier, polyvinylchloride (PVC) as a matrix, and diocthylphetalate (DOP) as a plasticizer for making an ion selective electrode for measurement of Tl+ cation in solutions. The amount of 4'-nitrobenzo-18C6 and polyvinylchloride were optimized in the preparation of the membrane. The response of the electrode was Nernstian within the concentration range 1.0 × 10-8 to 1.0 × 10-1M. This sensor displays a drift in Nernstian response for this cation with increasing the amount of ionophore and decreasing the amount of polyvinylchloride.The results of potentiometric measurements showed that, this electrode also responses to Cu2+ Ni2+ and Pb2+ cations, but the electrode has a wider dynamic range and a lower detection limit to Tl+ cation. The effects of various parameters such as pH, different cations interferences, effect of the amount of ionophore and polyvinylchloride and time on response of the coated ion selective electrode were investigated. Finally the constructed electrode was used in complexometric and precipitation titrations of Tl+ cation with EDTA and KBr, respectively. The response of the fabricated electrode at concentration range from 1.0 × 10-8 to 1.0 × 10-1M is linear with a Nernstian slope of 57.27 mV.

  16. Polymeric matrix membrane sensors for stability-indicating potentiometric determination of oxybutynin hydrochloride and flavoxate hydrochloride urogenital system drugs.

    Science.gov (United States)

    Heba, Mohamed; Ramadan, Nesrin; El-Laithy, Moustafa

    2008-01-01

    Four polyvinyl chloride (PVC) matrix membrane electrodes responsive to 2 drugs affecting the urogenital system--oxybutynin hydrochloride (OX) and flavoxate hydrochloride (FX)--were developed, described, and characterized. A precipitation-based technique with tungstophosphate (TP) and ammonium reineckate (R) anions as electroactive materials in a PVC matrix with an OX cation was used for electrode 1 and 2 fabrication, respectively. Electrode 3 and 4 fabrication was based on use of the precipitation technique of FX cation with tetrakis (4-chlorophenyl) borate and R anions as electroactive materials. Fast and stable Nernstian responses in the range 1 x 10(-2)-1 x 10(-6) M for the 2 drugs over the pH range 5-8 revealed the performance characteristics of these electrodes, which were evaluated according to International Union of Pure and Applied Chemistry recommendations. The method was applied to FX and OX in their pharmaceutical formulations and in human plasma samples. The 4 proposed sensors were found to be specific for the drugs in the presence of up to 60% of their degradation products. Validation of the method according to the quality assurance standards showed suitability of the proposed electrodes for use in the quality control assessment of these drugs. The recoveries for determination of the drugs by the 4 proposed selective electrodes were 99.5 +/- 0.5, 100.0 +/- 0.4, 99.9 +/- 0.4, and 100.1 +/- 0.4% for sensors 1-4, respectively. Statistical comparison between the results obtained by this method and the official method of the drugs was done, and no significant difference found.

  17. PRIORITY BASED PACKET SCHEDULING APPROACH FOR WIRELESS SENSOR NETWORKS

    OpenAIRE

    K. K. Kannan

    2017-01-01

    A priority based packet scheduling scheme is proposed which aims at scheduling different types of data packets, such as real time and non-real-time data packets at sensor nodes with resource constraints in Wireless Sensor Networks. Most of the existing packet-scheduling mechanisms of Wireless Sensor Networks use First Come First Served (FCFS), non-preemptive priority and preemptive priority scheduling algorithms. These algorithms results in long end-to-end data transmission delay, high energy...

  18. The activation loop of PIP5K functions as a membrane sensor essential for lipid substrate processing

    Science.gov (United States)

    Liu, Aizhuo; Sui, Dexin; Wu, Dianqing; Hu, Jian

    2016-01-01

    Phosphatidylinositol 4-phosphate 5-kinase (PIP5K), a representative member of the phosphatidylinositol phosphate kinase (PIPK) family, is a major enzyme that biosynthesizes the signaling molecule PI(4,5)P2 (phosphatidylinositol 4,5-bisphosphate) in eukaryotic cells. The stringent specificity toward lipid substrates and the high sensitivity to the membrane environment strongly suggest a membrane-sensing mechanism, but the underlying structural basis is still largely unknown. We present a nuclear magnetic resonance (NMR) study on a peptide commensurate with a PIP5K’s activation loop, which has been reported to be a determinant of lipid substrate specificity and subcellular localization of PIP5K. Although the activation loop is severely disordered in the crystal structure of PIP5K, the NMR experiments showed that the largely unstructured peptide folded into an amphipathic helix upon its association with the 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) micellar surface. Systematic mutagenesis and functional assays further demonstrated the crucial roles of the amphipathic helix and its hydrophobic surface in kinase activity and membrane-sensing function, supporting a working model in which the activation loop is a critical structural module conferring a membrane-sensing mechanism on PIP5K. The activation loop, surprisingly functioning as a membrane sensor, represents a new paradigm of kinase regulation by the activation loop through protein-membrane interaction, which also lays a foundation on the regulation of PIP5K (and other PIPKs) by membrane lipids for future studies. PMID:28138522

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

    Science.gov (United States)

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

    2016-06-12

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

  20. Patient Posture Monitoring System Based on Flexible Sensors

    Directory of Open Access Journals (Sweden)

    Youngsu Cha

    2017-03-01

    Full Text Available Monitoring patients using vision cameras can cause privacy intrusion problems. In this paper, we propose a patient position monitoring system based on a patient cloth with unobtrusive sensors. We use flexible sensors based on polyvinylidene fluoride, which is a flexible piezoelectric material. Theflexiblesensorsareinsertedintopartsclosetothekneeandhipoftheloosepatientcloth. We measure electrical signals from the sensors caused by the piezoelectric effect when the knee and hip in the cloth are bent. The measured sensor outputs are transferred to a computer via Bluetooth. We use a custom-made program to detect the position of the patient through a rule-based algorithm and the sensor outputs. The detectable postures are based on six human motions in and around a bed. The proposed system can detect the patient positions with a success rate over 88 percent for three patients.

  1. Ion Based High-Temperature Pressure Sensor

    National Research Council Canada - National Science Library

    Zdenek, Jeffrey S; Anthenien, Ralph A

    2004-01-01

    .... The environment encountered in such engines necessitates high temperature and durable (vibration resistant) devices. Traditional pressure sensors can be used, however thermal insulating materials must be used to protect the diaphragm...

  2. Sensor-based assessment of herbicide effects

    DEFF Research Database (Denmark)

    Streibig, Jens Carl; Rasmussen, Jesper; Andújar, D.

    2014-01-01

    Non-destructive assessment of herbicide effects may be able to support integrated weed management. To test whether effects of herbicides on canopy variables could be detected by sensors, two crops were used as models and treated with herbicides at BBCH 20 using a logarithmic sprayer. Twelve days...... after spraying at BBCH 25 and 42 days after sowing, nine sensor systems scanned a spring barley and an oilseed rape field experiment sown at different densities and sprayed with increasing field rates of glyphosate and tribenuron-methyl. The objective was to compare ED50s for crops and weeds derived...... by the different sensors in relation to crop density and herbicides. Although sensors were not directly developed to detect herbicide symptoms, they all detected changes in canopy colours or height and crop density. Generally ED50s showed the same pattern in response to crop density within herbicide...

  3. Robotic Hand Controlling Based on Flexible Sensor

    OpenAIRE

    Bilgin, Süleyman; Üser, Yavuz; Mercan, Muhammet

    2016-01-01

    Today's technology has increased the interest in robotic systems andincrease the number of studies realized in this area.  There are many studies on robotic systems inseveral fields to facilitate human life in the literature. In this study, arobot hand is designed to repeat finger movements depending upon flexiblesensors mounted on any wearable glove. In the literature, various sensors thatdetect the finger movement are used. The sensor that detects the angle of thefingers has b...

  4. A novel PTFE-based proton-conductive membrane

    Science.gov (United States)

    Reichman, S.; Duvdevani, T.; Aharon, A.; Philosoph, M.; Golodnitsky, D.; Peled, E.

    The demand for a solid polymer electrolyte membrane (SPEM) for fuel-cell systems, capable of withstanding temperatures above 130 °C, decreasing the electrode-catalyst loadings and reducing poisoning by carbon monoxide, has prompted this study. A novel, low-cost, highly conductive, nanoporous proton-conducting membrane (NP-PCM) based on a polytetrafluoroethylene (PTFE) backbone has been developed. It comprises non-conductive nano-size ceramic powder, PTFE binder and an aqueous acid. The preparation procedures were studied and the membrane was characterized with the use of: SEM, EDS, pore-size-distribution measurements (PSD), TGA-DTA and electrochemical methods. The ionic conductivity of a membrane doped with 3 M sulfuric acid increases with the ceramic powder content and reaches 0.22 S cm -1 at 50% (v/v) silica. A non-optimized direct-methanol fuel cell (DMFC) with a 250 μm thick membrane has been assembled. It demonstrated 50 and 130 mW cm -2 at 80 and 130 °C, respectively. Future study will be directed to improving the membrane-preparation process, getting thinner membranes and using this membrane in a hydrogen-fed fuel cell.

  5. Ultrafast permeation of water through protein-based membranes.

    Science.gov (United States)

    Peng, Xinsheng; Jin, Jian; Nakamura, Yoshimichi; Ohno, Takahisa; Ichinose, Izumi

    2009-06-01

    Pressure-driven filtration by porous membranes is widely used in the production of drinking water from ground and surface water. Permeation theory predicts that filtration rate is proportional to the pressure difference across the filtration membrane and inversely proportional to the thickness of the membrane. However, these membranes need to be able to withstand high water fluxes and pressures, which means that the active separation layers in commercial filtration systems typically have a thickness of a few tens to several hundreds of nanometres. Filtration performance might be improved by the use of ultrathin porous silicon membranes or carbon nanotubes immobilized in silicon nitride or polymer films, but these structures are difficult to fabricate. Here, we report a new type of filtration membrane made of crosslinked proteins that are mechanically robust and contain channels with diameters of less than 2.2 nm. We find that a 60-nm-thick membrane can concentrate aqueous dyes from fluxes up to 9,000 l h(-1) m(-2) bar(-1), which is approximately 1,000 times higher than the fluxes that can be withstood by commercial filtration membranes with similar rejection properties. Based on these results and molecular dynamics simulations, we propose that protein-surrounded channels with effective lengths of less than 5.8 nm can separate dye molecules while allowing the ultrafast permeation of water at applied pressures of less than 1 bar.

  6. Correcting the wavefront aberration of membrane mirror based on liquid crystal spatial light modulator

    Science.gov (United States)

    Yang, Bin; Wei, Yin; Chen, Xinhua; Tang, Minxue

    2014-11-01

    Membrane mirror with flexible polymer film substrate is a new-concept ultra lightweight mirror for space applications. Compared with traditional mirrors, membrane mirror has the advantages of lightweight, folding and deployable, low cost and etc. Due to the surface shape of flexible membrane mirror is easy to deviate from the design surface shape, it will bring wavefront aberration to the optical system. In order to solve this problem, a method of membrane mirror wavefront aberration correction based on the liquid crystal spatial light modulator (LCSLM) will be studied in this paper. The wavefront aberration correction principle of LCSLM is described and the phase modulation property of a LCSLM is measured and analyzed firstly. Then the membrane mirror wavefront aberration correction system is designed and established according to the optical properties of a membrane mirror. The LCSLM and a Hartmann-Shack sensor are used as a wavefront corrector and a wavefront detector, respectively. The detected wavefront aberration is calculated and converted into voltage value on LCSLM for the mirror wavefront aberration correction by programming in Matlab. When in experiment, the wavefront aberration of a glass plane mirror with a diameter of 70 mm is measured and corrected for verifying the feasibility of the experiment system and the correctness of the program. The PV value and RMS value of distorted wavefront are reduced and near diffraction limited optical performance is achieved. On this basis, the wavefront aberration of the aperture center Φ25 mm in a membrane mirror with a diameter of 200 mm is corrected and the errors are analyzed. It provides a means of correcting the wavefront aberration of membrane mirror.

  7. Membranes of 5,10,15,20-Tetrakis(4-Methoxyphenyl Porphyrinatocobalt (TMOPP-Co (I as MoO42- - Selective Sensors

    Directory of Open Access Journals (Sweden)

    R. Mangla

    2002-05-01

    Full Text Available Polyvinyl chloride (PVC membrane electrodes based on porphyrin 5,10,15,20-tetrakis(4methoxyphenylporphyrinatocobalt (TMOPP-Co (I incorporating sodium tetra phenyl borate (NaTPB as anion excluder and dibutyl phthalate (DBP, dioctyl phthalate (DOP, dibutyl butyl phosphonate (DBBP, tri-n-butyl phosphate (TBP, and 1-chloronaphthalene (CN as plasticizing solvent mediators were prepared and tested for selective detection of molybdate ions. The membrane having anion excluder, NaTPB and DBP as plasticizer (membrane no. 2 proved to be best in terms of working concentration range 5.0×10-5 – 1.0×10-1M with a near – Nernstian slope of 32.0±1.0 mV/decade of activity over the pH range 5.4- 10.5. The response time of this sensor is 18s with a lifetime of about 4 months. The sensor can be used in non-aqueous medium with no significant change in the value of slope or working concentration range for the estimation of MoO42- in solutions having up to 25% (v/v non-aqueous fraction.

  8. Illumination-based synchronization of high-speed vision sensors.

    Science.gov (United States)

    Hou, Lei; Kagami, Shingo; Hashimoto, Koichi

    2010-01-01

    To acquire images of dynamic scenes from multiple points of view simultaneously, the acquisition time of vision sensors should be synchronized. This paper describes an illumination-based synchronization method derived from the phase-locked loop (PLL) algorithm. Incident light to a vision sensor from an intensity-modulated illumination source serves as the reference signal for synchronization. Analog and digital computation within the vision sensor forms a PLL to regulate the output signal, which corresponds to the vision frame timing, to be synchronized with the reference. Simulated and experimental results show that a 1,000 Hz frame rate vision sensor was successfully synchronized with 32 μs jitters.

  9. A carbon nanotube based ammonia sensor on cotton textile

    Science.gov (United States)

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

    2013-05-01

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

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

    Science.gov (United States)

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

    2016-03-02

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

  11. MEMS magnetic field sensor based on silicon bridge structure

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-10-15

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

  12. Ultrasensitive displacement sensor based on tunable horn-shaped resonators

    Science.gov (United States)

    Tian, Ying; Wu, Jiong; Yu, Le; Yang, Helin; Huang, Xiaojun

    2018-04-01

    In this paper, we proposed a novel double-deck displacement sensor with a high linearity based on tunable horn-shaped resonators. The designed sensor included two substrate layers etched with copper metallization in various shapes. When the upper trip-type resonator layer has a relative displacement to the bottom horn-shaped resonator layer, the resonance frequency of the sensor is redshift. High sensitivity of the sensor is around 207.2 MHz mm‑1 with 4 mm linear dynamic range. We fabricate the sample of the proposed displacement sensor, in addition the simulated results are verified by experiment. The proposed displacement sensor is appropriate for using MEMS technology in further miniaturization.

  13. Chip-Based Sensors for Disease Diagnosis

    Science.gov (United States)

    Fang, Zhichao

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

  14. A Wildlife Monitoring System Based on Wireless Image Sensor Networks

    Directory of Open Access Journals (Sweden)

    Junguo Zhang

    2014-10-01

    Full Text Available Survival and development of wildlife sustains the balance and stability of the entire ecosystem. Wildlife monitoring can provide lots of information such as wildlife species, quantity, habits, quality of life and habitat conditions, to help researchers grasp the status and dynamics of wildlife resources, and to provide basis for the effective protection, sustainable use, and scientific management of wildlife resources. Wildlife monitoring is the foundation of wildlife protection and management. Wireless Sensor Networks (WSN technology has become the most popular technology in the field of information. With advance of the CMOS image sensor technology, wireless sensor networks combined with image sensors, namely Wireless Image Sensor Networks (WISN technology, has emerged as an alternative in monitoring applications. Monitoring wildlife is one of its most promising applications. In this paper, system architecture of the wildlife monitoring system based on the wireless image sensor networks was presented to overcome the shortcomings of the traditional monitoring methods. Specifically, some key issues including design of wireless image sensor nodes and software process design have been studied and presented. A self-powered rotatable wireless infrared image sensor node based on ARM and an aggregation node designed for large amounts of data were developed. In addition, their corresponding software was designed. The proposed system is able to monitor wildlife accurately, automatically, and remotely in all-weather condition, which lays foundations for applications of wireless image sensor networks in wildlife monitoring.

  15. Mercury(II) selective sensors based on AlGaN/GaN transistors.

    Science.gov (United States)

    Asadnia, Mohsen; Myers, Matthew; Akhavan, N D; O'Donnell, Kane; Umana-Membreno, Gilberto A; Mishra, U K; Nener, Brett; Baker, Murray; Parish, Giacinta

    2016-11-02

    This work presents the first polymer approach to detect metal ions using AlGaN/GaN transistor-based sensor. The sensor utilised an AlGaN/GaN high electron mobility transistor-type structure by functionalising the gate area with a polyvinyl chloride (PVC) based ion selective membrane. Sensors based on this technology are portable, robust and typically highly sensitive to the target analyte; in this case Hg 2+ . This sensor showed a rapid and stable response when it was introduced to solutions of varying Hg 2+ concentrations. At pH 2.8 in a 10 -2  M KNO 3 ion buffer, a detection limit below 10 -8  M and a linear response range between 10 -8  M-10 -4  M were achieved. This detection limit is an order of magnitude lower than the reported detection limit of 10 -7  M for thioglycolic acid monolayer functionalised AlGaN/GaN HEMT devices. Detection limits of approximately 10 -7  M and 10 -6  M in 10 -2  M Cd(NO 3 ) 2 and 10 -2  M Pb(NO 3 ) 2 ion buffers were also achieved, respectively. Furthermore, we show that the apparent gate response was near-Nernstian under various conditions. X-ray photoelectron spectroscopy (XPS) experiments confirmed that the sensing membrane is reversible after being exposed to Hg 2+ solution and rinsed with deionised water. The success of this study precedes the development of this technology in selectively sensing multiple ions in water with use of the appropriate polymer based membranes on arrays of devices. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

  16. A spectrofluorimetric sensor based on grape skin tissue for ...

    African Journals Online (AJOL)

    A spectrofluorimetric method based on the grape skin has been developed for the determination of Fe3+ at pH 5.0. The emission wavelength of the grape skin sensor occurs at 680 nm and the excitation wavelength at 421 nm. The fluorescence of sensor could be quenched by Fe3+ due to the complexing ability of ...

  17. Combine harvester monitor system based on wireless sensor network

    Science.gov (United States)

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

  18. Bio-inspired hair-based inertial sensors

    NARCIS (Netherlands)

    Droogendijk, H.; de Boer, Meint J.; Sanders, Remco G.P.; Krijnen, Gijsbertus J.M.

    2015-01-01

    In biology, hair-based sensor systems are used regularly for measurement of physical quantities like acceleration, flow, rotational rate, and IR light. In this chapter, two different types of bio-inspired sensors for inertial measurement are discussed, which have been developed using surface

  19. A quinoline based pH sensitive ratiometric fluorescent sensor ...

    Indian Academy of Sciences (India)

    Abstract. A new quinoline based hydrazone was synthesized via a condensation reaction and characterized by NMR, mass and single crystal X-ray diffraction studies. It was investigated for suitability as a reversible ratiometric fluorescent pH sensor in acidic pH region. The sensor exhibits intramolecular charge transfer (ICT).

  20. A quinoline based pH sensitive ratiometric fluorescent sensor ...

    Indian Academy of Sciences (India)

    A new quinoline based hydrazone was synthesized via a condensation reaction and characterized by NMR, mass and single crystal X-ray diffraction studies. It was investigated for suitability as a reversible ratiometric fluorescent pH sensor in acidic pH region. The sensor exhibits intramolecular charge transfer (ICT) type ...

  1. POF based glucose sensor incorporating grating wavelength filters

    DEFF Research Database (Denmark)

    Hassan, Hafeez Ul; Aasmul, Søren; Bang, Ole

    2014-01-01

    AND RESEARCH IN POLYMER OPTICAL DEVICES; TRIPOD. Within the domain of TRIPOD, research is conducted on "Plastic Optical Fiber based Glucose Sensors Incorporating Grating Wavelength Filters". Research will be focused to optimized fiber tips for better coupling efficiency, reducing the response time of sensor...

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

    Science.gov (United States)

    Siroký, K; Jiresová, J

    1994-10-01

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

  3. Study of YSZ-based electrochemical sensors with oxide electrodes ...

    Indian Academy of Sciences (India)

    Potentiometric sensors based on yttria stabilized zirconia (YSZ) with WO3 as sensing electrode were fabricated using either Pt or Au electrodes. The sensors were studied in the temperature range 550–700°C in the presence of different concentrations (300–1000 ppm) of NO2 and CO in air. The response to NO2 was very ...

  4. A spectrofluorimetric sensor based on grape skin tissue for ...

    African Journals Online (AJOL)

    The fluorescence of sensor could be quenched by Fe3+ due to the complexing ability of anthocyanin with the metal ions. Anthocyanin, the main pigment in the grape skin, has been found fluorescence sensing material. The sensor based on the grape skin exhibited a calibration response for Fe3+ in two concentration ...

  5. Reviewing Automated Sensor-Based Visitor Tracking Studies

    DEFF Research Database (Denmark)

    Mygind, Lærke; Bentsen, Peter

    2017-01-01

    methods in terms of obtained level of detail, accuracy, level of obtrusiveness, automation of data entry, ability to time concurrent behaviors, and amount of observer training needed. Although individual sensor-based and traditional, observational methods had both strengths and weaknesses, all sensor...

  6. In plane optical sensor based on organic electronic devices

    NARCIS (Netherlands)

    Koetse, M.M; Rensing, P.A.; Heck, G.T. van; Sharpe, R.B.A.; Allard, B.A.M.; Wieringa, F.P.; Kruijt, P.G.M.; Meulendijks, N.M.M.; Jansen, H.; Schoo, H.F.M.

    2008-01-01

    Sensors based on organic electronic devices are emerging in a wide range of application areas. Here we present a sensor platform using organic light emitting diodes (OLED) and organic photodiodes (OPD) as active components. By means of lamination and interconnection technology the functional foils

  7. Evaluation of accelerometer based multi-sensor versus single-sensor activity recognition systems.

    Science.gov (United States)

    Gao, Lei; Bourke, A K; Nelson, John

    2014-06-01

    Physical activity has a positive impact on people's well-being and it had been shown to decrease the occurrence of chronic diseases in the older adult population. To date, a substantial amount of research studies exist, which focus on activity recognition using inertial sensors. Many of these studies adopt a single sensor approach and focus on proposing novel features combined with complex classifiers to improve the overall recognition accuracy. In addition, the implementation of the advanced feature extraction algorithms and the complex classifiers exceed the computing ability of most current wearable sensor platforms. This paper proposes a method to adopt multiple sensors on distributed body locations to overcome this problem. The objective of the proposed system is to achieve higher recognition accuracy with "light-weight" signal processing algorithms, which run on a distributed computing based sensor system comprised of computationally efficient nodes. For analysing and evaluating the multi-sensor system, eight subjects were recruited to perform eight normal scripted activities in different life scenarios, each repeated three times. Thus a total of 192 activities were recorded resulting in 864 separate annotated activity states. The methods for designing such a multi-sensor system required consideration of the following: signal pre-processing algorithms, sampling rate, feature selection and classifier selection. Each has been investigated and the most appropriate approach is selected to achieve a trade-off between recognition accuracy and computing execution time. A comparison of six different systems, which employ single or multiple sensors, is presented. The experimental results illustrate that the proposed multi-sensor system can achieve an overall recognition accuracy of 96.4% by adopting the mean and variance features, using the Decision Tree classifier. The results demonstrate that elaborate classifiers and feature sets are not required to achieve high

  8. Piezoelectric Zinc Oxide Based MEMS Acoustic Sensor

    Directory of Open Access Journals (Sweden)

    Aarti Arora

    2008-04-01

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

  9. A Risk-Based Sensor Placement Methodology

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ronald W [ORNL; Kulesz, James J [ORNL

    2006-08-01

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

  10. Multipoint sensor based on fiber Bragg gratings

    International Nuclear Information System (INIS)

    Mendez-Zepeda, O; Munoz-Aguirre, S; Beltran-Perez, G; Castillo-Mixcoatl, J

    2011-01-01

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

  11. Interaction of the Spo20 membrane-sensor motif with phosphatidic acid and other anionic lipids, and influence of the membrane environment.

    Directory of Open Access Journals (Sweden)

    Habib Horchani

    Full Text Available The yeast protein Spo20 contains a regulatory amphipathic motif that has been suggested to recognize phosphatidic acid, a lipid involved in signal transduction, lipid metabolism and membrane fusion. We have investigated the interaction of the Spo20 amphipathic motif with lipid membranes using a bioprobe strategy that consists in appending this motif to the end of a long coiled-coil, which can be coupled to a GFP reporter for visualization in cells. The resulting construct is amenable to in vitro and in vivo experiments and allows unbiased comparison between amphipathic helices of different chemistry. In vitro, the Spo20 bioprobe responded to small variations in the amount of phosphatidic acid. However, this response was not specific. The membrane binding of the probe depended on the presence of phosphatidylethanolamine and also integrated the contribution of other anionic lipids, including phosphatidylserine and phosphatidyl-inositol-(4,5bisphosphate. Inverting the sequence of the Spo20 motif neither affected the ability of the probe to interact with anionic liposomes nor did it modify its cellular localization, making a stereo-specific mode of phosphatidic acid recognition unlikely. Nevertheless, the lipid binding properties and the cellular localization of the Spo20 alpha-helix differed markedly from that of another amphipathic motif, Amphipathic Lipid Packing Sensor (ALPS, suggesting that even in the absence of stereo specific interactions, amphipathic helices can act as subcellular membrane targeting determinants in a cellular context.

  12. Plastic optical fiber level measurement sensor based on side holes

    Science.gov (United States)

    Park, Young June; Shin, Jong-Dug; Park, Jaehee

    2014-10-01

    Plastic optical fiber level measurement sensor based on in-line side holes is investigated theoretically and experimentally. The sensor consists of a plastic optical fiber with in-line side holes spaced about 5 cm apart. The 0.9 diameter in-line side holes were fabricated by micro-drilling. An analytical expression of the sensor transmittance was obtained using a simple ray optics approach. The measurements of the sensor transmittance were performed with a 55 cm height Mass cylinder. Both results show that the sensor transmittance increases as the number of side holes filled with water increases. The research results indicate that the plastic optical fiber based on in-line side holes can be used for water level measurement.

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

    Science.gov (United States)

    Wagner, Raymond S.

    2010-01-01

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

  14. Differential Ring Oscillator Based Capacitance Sensor for Microfluidic Applications.

    Science.gov (United States)

    Mohammad, Kaveh; Thomson, Douglas J

    2017-04-01

    A simple high frequency capacitance sensor with 180 aF sensitivity is designed for a wide range of microfluidic applications. The sensor is implemented utilizing differential ring oscillators operating at [Formula: see text] MHz with a differential signal at [Formula: see text] MHz. The sensor occupies [Formula: see text] cm × 2 cm on a printed circuit board. The sensor is tuned using two precision variable capacitors and has a full scale range of [Formula: see text] pF. The sensor was able to detect less than 1% Isopropyl Alcohol in DI water and to detect 15 μm polystyrene spheres flowing over 25 μm lines and spaces coplanar electrodes in a microfluidic channel. The compact differential ring oscillator based architecture of the design makes it suitable to be integrated into microprocessor based systems for detection in Lab on Chip or Lab on Board applications.

  15. Membrane-based seawater desalination: Present and future prospects

    KAUST Repository

    Amy, Gary L.

    2016-10-20

    Given increasing regional water scarcity and that almost half of the world\\'s population lives within 100 km of an ocean, seawater represents a virtually infinite water resource. However, its exploitation is presently limited by the significant specific energy consumption (kWh/m) required by conventional desalination technologies, further exasperated by high unit costs ($/m) and environmental impacts including GHG emissions (g CO-eq/m), organism impingement/entrainment through intakes, and brine disposal through outfalls. This paper explores the state-of-the-art in present seawater desalination practice, emphasizing membrane-based technologies, while identifying future opportunities in step improvements to conventional technologies and development of emerging, potentially disruptive, technologies through advances in material science, process engineering, and system integration. In this paper, seawater reverse osmosis (RO) serves as the baseline conventional technology. The discussion extends beyond desalting processes into membrane-based salinity gradient energy production processes, which can provide an energy offset to desalination process energy requirements. The future membrane landscape in membrane-based desalination and salinity gradient energy is projected to include ultrahigh permeability RO membranes, renewable-energy driven desalination, and emerging processes including closed-circuit RO, membrane distillation, forward osmosis, pressure retarded osmosis, and reverse electrodialysis according various niche applications and/or hybrids, operating separately or in conjunction with RO.

  16. Membrane-based removal of volatile methylsiloxanes from biogas

    Energy Technology Data Exchange (ETDEWEB)

    Ajhar, Marc

    2011-12-16

    This work investigates the removal of volatile methylsiloxanes (VMS) from biogas using dense, rubbery membranes. It consists of the following: a) thorough overview of already established and still developing siloxane removal technologies, b) detailed investigation of a viable sampling and analytical method, c) screening of different elastomers to identify siloxane-selective membrane materials, d) design of a suitable membrane structure, i.e. theoretical considerations about the thicknesses of the active separation layer and the porous support layer, e) assessment of the siloxane separation performance of a silicone membrane module using both synthetic gas under laboratory conditions and real landfill gas, f) comparison between the state-of-the-art technology (adsorption on activated carbon) and membrane-based processes. Suitable polymers for siloxane removal from biogas exist, however, they are not commercially available as membranes. Among the elastomers studied, Pebax registered 2533 is particularly promising. The use of a membrane made of this material could potentially become new state-of-the-art technology.

  17. Membrane Guanylate Cyclase catalytic Subdomain: Structure and Linkage with Calcium Sensors and Bicarbonate

    Directory of Open Access Journals (Sweden)

    Sarangan Ravichandran

    2017-06-01

    Full Text Available Membrane guanylate cyclase (MGC is a ubiquitous multi-switching cyclic GMP generating signaling machine linked with countless physiological processes. In mammals it is encoded by seven distinct homologous genes. It is a single transmembrane spanning multi-modular protein; composed of integrated blocks and existing in homo-dimeric form. Its core catalytic domain (CCD module is a common transduction center where all incoming signals are translated into the production of cyclic GMP, a cellular signal second messenger. Crystal structure of the MGC’s CCD does not exist and its precise identity is ill-defined. Here, we define it at a sub-molecular level for the phototransduction-linked MGC, the rod outer segment guanylate cyclase type 1, ROS-GC1. (1 The CCD is a conserved 145-residue structural unit, represented by the segment V820-P964. (2 It exists as a homo-dimer and contains seven conserved catalytic elements (CEs wedged into seven conserved motifs. (3 It also contains a conserved 21-residue neurocalcin δ-modulated structural domain, V836-L857. (4 Site-directed mutagenesis documents that each of the seven CEs governs the cyclase’s catalytic activity. (5 In contrast to the soluble and the bacterium MGC which use Mn2+-GTP substrate for catalysis, MGC CCD uses the natural Mg2+-GTP substrate. (6 Strikingly, the MGC CCD requires anchoring by the Transmembrane Domain (TMD to exhibit its major (∼92% catalytic activity; in isolated form the activity is only marginal. This feature is not linked with any unique sequence of the TMD; there is minimal conservation in TMD. Finally, (7 the seven CEs control each of four phototransduction pathways- -two Ca2+-sensor GCAPs-, one Ca2+-sensor, S100B-, and one bicarbonate-modulated. The findings disclose that the CCD of ROS-GC1 has built-in regulatory elements that control its signal translational activity. Due to conservation of these regulatory elements, it is proposed that these elements also control the

  18. Key steps in type III secretion system (T3SS) towards translocon assembly with potential sensor at plant plasma membrane.

    Science.gov (United States)

    Ji, Hongtao; Dong, Hansong

    2015-09-01

    Many plant- and animal-pathogenic Gram-negative bacteria employ the type III secretion system (T3SS) to translocate effector proteins from bacterial cells into the cytosol of eukaryotic host cells. The effector translocation occurs through an integral component of T3SS, the channel-like translocon, assembled by hydrophilic and hydrophobic proteinaceous translocators in a two-step process. In the first, hydrophilic translocators localize to the tip of a proteinaceous needle in animal pathogens, or a proteinaceous pilus in plant pathogens, and associate with hydrophobic translocators, which insert into host plasma membranes in the second step. However, the pilus needs to penetrate plant cell walls in advance. All hydrophilic translocators so far identified in plant pathogens are characteristic of harpins: T3SS accessory proteins containing a unitary hydrophilic domain or an additional enzymatic domain. Two-domain harpins carrying a pectate lyase domain potentially target plant cell walls and facilitate the penetration of the pectin-rich middle lamella by the bacterial pilus. One-domain harpins target plant plasma membranes and may play a crucial role in translocon assembly, which may also involve contrapuntal associations of hydrophobic translocators. In all cases, sensory components in the target plasma membrane are indispensable for the membrane recognition of translocators and the functionality of the translocon. The conjectural sensors point to membrane lipids and proteins, and a phosphatidic acid and an aquaporin are able to interact with selected harpin-type translocators. Interactions between translocators and their sensors at the target plasma membrane are assumed to be critical for translocon assembly. © 2014 BSPP AND JOHN WILEY & SONS LTD.

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

    Science.gov (United States)

    Bolling, Sam

    2012-06-01

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

  20. A Novel Ion - selective Polymeric Membrane Sensor for Determining Thallium(I) With High Selectivity

    Energy Technology Data Exchange (ETDEWEB)

    Kassim, Anuar; Rezayi, Majid; Ahmadzadeh, Saeid; Yusof, Noor Azah; Tee, Tan Wee; Abdullah, Abd Halim [Department of Chemistry Faculty of Science, Universiti Putra Malaysia 43400 Serdang, Selangor (Malaysia); Rounaghi, Gholamhossein; Mohajeri, Masoomeh [Department of Chemistry, Factuality of Sciences, Islamic Azad University of Mashhad, Mashhad (Iran, Islamic Republic of); Heng, Lee Yook, E-mail: anuar@science.upm.edu.my [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor D.E. (Malaysia)

    2011-02-15

    Thallium is a toxic metal that introduced into the environment mainly as a waste from the production of zinc, cadmium, and lead and by combustion of coal. Thallium causes gastrointestinal irritation and nerve damage when people are exposed to it for relatively short period of time. For long term, thallium has the potential to cause the following effects: change in blood chemistry, damage to liver, kidney, intestinal and testicular tissue, and hair loss. In this work a membrane was prepared by use of 4'-nitrobenzo -18-crown-6 (4'NB18C6) as an ion carrier, polyvinylchloride (PVC) as a matrix, and diocthylphetalate (DOP) as a plasticizer for making an ion selective electrode for measurement of Tl{sup +} cation in solutions. The amount of 4'-nitrobenzo-18C6 and polyvinylchloride were optimized in the preparation of the membrane. The response of the electrode was Nernstian within the concentration range 1.0 x 10{sup -8} to 1.0 x 10{sup -1}M. This sensor displays a drift in Nernstian response for this cation with increasing the amount of ionophore and decreasing the amount of polyvinylchloride.The results of potentiometric measurements showed that, this electrode also responses to Cu{sup 2+} Ni{sup 2+} and Pb{sup 2+} cations, but the electrode has a wider dynamic range and a lower detection limit to Tl{sup +} cation. The effects of various parameters such as pH, different cations interferences, effect of the amount of ionophore and polyvinylchloride and time on response of the coated ion selective electrode were investigated. Finally the constructed electrode was used in complexometric and precipitation titrations of Tl{sup +} cation with EDTA and KBr, respectively. The response of the fabricated electrode at concentration range from 1.0 x 10{sup -8} to 1.0 x 10{sup -1}M is linear with a Nernstian slope of 57.27 mV.

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

    Directory of Open Access Journals (Sweden)

    William Richard Kennon

    2013-08-01

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

  2. Nanofiber based triple layer hydro-philic/-phobic membrane - a solution for pore wetting in membrane distillation

    Science.gov (United States)

    Prince, J. A.; Rana, D.; Matsuura, T.; Ayyanar, N.; Shanmugasundaram, T. S.; Singh, G.

    2014-11-01

    The innovative design and synthesis of nanofiber based hydro-philic/phobic membranes with a thin hydro-phobic nanofiber layer on the top and a thin hydrophilic nanofiber layer on the bottom of the conventional casted micro-porous layer which opens up a solution for membrane pore wetting and improves the pure water flux in membrane distillation.

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

    Science.gov (United States)

    Almasri, Marwah; Elleithy, Khaled; Alajlan, Abrar

    2015-01-01

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

  4. Capillarity-based preparation system for optical colorimetric sensor arrays.

    Science.gov (United States)

    Luo, Xiao-Gang; Yi, Xin; Bu, Xiang-Nan; Hou, Chang-Jun; Huo, Dan-Qun; Yang, Mei; Fa, Huan-Bao; Lei, Jin-Can

    2017-03-01

    In recent years, optical colorimetric sensor arrays have demonstrated beneficial features, including rapid response, high selectivity, and high specificity; as a result, it has been extensively applied in food inspection and chemical studies, among other fields. There are instruments in the current market available for the preparation of an optical colorimetric sensor array, but it lacks the corresponding research of the preparation mechanism. Therefore, in connection with the main features of this kind of sensor array such as consistency, based on the preparation method of contact spotting, combined with a capillary fluid model, Washburn equation, Laplace equation, etc., this paper develops a diffusion model of an optical colorimetric sensor array during its preparation and sets up an optical colorimetric sensor array preparation system based on this diffusion model. Finally, this paper compares and evaluates the sensor arrays prepared by the system and prepared manually in three aspects such as the quality of array point, response of array, and response result, and the results show that the performance index of the sensor array prepared by a system under this diffusion model is better than that of the sensor array of manual spotting, which meets the needs of the experiment.

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

    Directory of Open Access Journals (Sweden)

    Marwah Almasri

    2015-12-01

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

  6. Nano-fin based mercury-sensor for environmental surveillance.

    Science.gov (United States)

    Keller, L O; Kallis, K T; Fiedler, H L

    2010-09-01

    This Nano-Fin-Sensor bases on a lithography-independent technology-process, enabling research on Nano-Sensors without cost-intensive technology-equipment. Background for the sensor described within this paper is the high pollution with mercury of the environment and the lack of cheap, easy to use and portable sensors. The lithography-independent process is based on a "deposition and etch-back" technique defining Nano-Fins. Active sensor-material is a gold-layer, deposited on the fin, increasing resistance being exposed to mercury-vapor due to the process of amalgamation. Regeneration is done by heating-up the gold-layer using the poly-silicon fin as resistance-heating-device driving out the adsorbed mercury. To increase the measurement-accuracy, the sensor is made up of four Nano-Fin-Sensors, connected as Wheatstone-bridge. Two sensors have to be passivated by a mercury diffusion barrier, here a silicon-nitride-layer.

  7. Integrated ion sensor device applications based on printed hybrid material systems (Conference Presentation)

    Science.gov (United States)

    List-Kratochvil, Emil J. W.

    2016-09-01

    Comfortable, wearable sensors and computers will enhance every person's awareness of his or her health condition, environment, chemical pollutants, potential hazards, and information of interest. In agriculture and in the food industry there is a need for a constant control of the condition and needs of plants, animals, and farm products. Yet many of these applications depend upon the development of novel, cheap devices and sensors that are easy to implement and to integrate. Organic semiconductors as well as several inorganic materials and hybrid material systems have proven to combine a number of intriguing optical and electronic properties with simple processing methods. As it will be reviewed in this contribution, these materials are believed to find their application in printed electronic devices allowing for the development of smart disposable devices in food-, health-, and environmental monitoring, diagnostics and control, possibly integrated into arrays of sensor elements for multi-parameter detection. In this contribution we review past and recent achievements in the field. Followed by a brief introduction, we will focus on two topics being on the agenda recently: a) the use of electrolyte-gated organic field-effect transistor (EGOFET) and ion-selective membrane based sensors for in-situ sensing of ions and biological substances and b) the development of hybrid material based resistive switches and their integration into fully functional, printed hybrid crossbar sensor array structures.

  8. Catalyst Degradation in High Temperature Proton Exchange Membrane Fuel Cells Based on Acid Doped Polybenzimidazole Membranes

    DEFF Research Database (Denmark)

    Cleemann, Lars Nilausen; Buazar, F.; Li, Qingfeng

    2013-01-01

    confirmed by the post TEM and XRD analysis. A strong dependence of the fuel cell performance degradation on the catalyst supports was observed. Graphitization of the carbon blacks improved the stability and catalyst durability though at the expense of a significant decrease in the specific surface area......Degradation of carbon supported platinum catalysts is a major failure mode for the long term durability of high temperature proton exchange membrane fuel cells based on phosphoric acid doped polybenzimidazole membranes. With Vulcan carbon black as a reference, thermally treated carbon black...... and multi‐walled carbon nanotubes were used as supports for electrode catalysts and evaluated in accelerated durability tests under potential cycling at 150 °C. Measurements of open circuit voltage, area specific resistance and hydrogen permeation through the membrane were carried out, indicating little...

  9. A Solid-Contact Indium(III) Sensor based on a Thiosulfinate Ionophore Derived from Omeprazole

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, Mohammad Nooredeen; Hend Samy Amer [National Research Centre, Cairo (Egypt)

    2013-04-15

    A novel solid-contact indium(III)-selective sensor based on bis-(1H-benzimidazole-5-methoxy-2-[(4-methoxy-3, 5-dimethyl-1-pyridinyl) 2-methyl]) thiosulfinate, known as an omeprazole dimer (OD) and a neutral ionophore, was constructed, and its performance characteristics were evaluated. The sensor was prepared by applying a membrane cocktail containing the ionophore to a graphite rod pre-coated with polyethylene dioxythiophene (PEDOT) conducting polymer as the ion-to-electron transducer. The membrane contained 3.6% OD, 2.3% oleic acid (OA) and 62% dioctyl phthalate (DOP) as the solvent mediator in PVC and produced a good potentiometric response to indium(III) ions with a Nernstian slope of 19.09 mV/decade. The constructed sensor possessed a linear concentration range from 3 Χ 10{sup -7} to 1 Χ 10{sup -2} M and a lower detection limit (LDL) of 1 Χ 10{sup -7} M indium(III) over a pH range of 4.0-7.0. It also displayed a fast response time and good selectivity for indium(III) over several other ions. The sensor can be used for longer than three months without any considerable divergence in potential. The sensor was utilized for direct and flow injection potentiometric (FIP) determination of indium(III) in alloys. The parameters that control the flow injection method were optimized. Indium(III) was quantitatively recovered, and the results agreed with those obtained using atomic absorption spectrophotometry, as confirmed by the f and t values. The sensor was also utilized as an indicator electrode for the potentiometric titration of fluoride in the presence of chloride, bromide, iodide and thiocyanate ions using indium(III) nitrate as the titrant.

  10. A Solid-Contact Indium(III) Sensor based on a Thiosulfinate Ionophore Derived from Omeprazole

    International Nuclear Information System (INIS)

    Abbas, Mohammad Nooredeen; Hend Samy Amer

    2013-01-01

    A novel solid-contact indium(III)-selective sensor based on bis-(1H-benzimidazole-5-methoxy-2-[(4-methoxy-3, 5-dimethyl-1-pyridinyl) 2-methyl]) thiosulfinate, known as an omeprazole dimer (OD) and a neutral ionophore, was constructed, and its performance characteristics were evaluated. The sensor was prepared by applying a membrane cocktail containing the ionophore to a graphite rod pre-coated with polyethylene dioxythiophene (PEDOT) conducting polymer as the ion-to-electron transducer. The membrane contained 3.6% OD, 2.3% oleic acid (OA) and 62% dioctyl phthalate (DOP) as the solvent mediator in PVC and produced a good potentiometric response to indium(III) ions with a Nernstian slope of 19.09 mV/decade. The constructed sensor possessed a linear concentration range from 3 Χ 10 -7 to 1 Χ 10 -2 M and a lower detection limit (LDL) of 1 Χ 10 -7 M indium(III) over a pH range of 4.0-7.0. It also displayed a fast response time and good selectivity for indium(III) over several other ions. The sensor can be used for longer than three months without any considerable divergence in potential. The sensor was utilized for direct and flow injection potentiometric (FIP) determination of indium(III) in alloys. The parameters that control the flow injection method were optimized. Indium(III) was quantitatively recovered, and the results agreed with those obtained using atomic absorption spectrophotometry, as confirmed by the f and t values. The sensor was also utilized as an indicator electrode for the potentiometric titration of fluoride in the presence of chloride, bromide, iodide and thiocyanate ions using indium(III) nitrate as the titrant

  11. Tin(II Selective PVC Membrane Electrode Based on Salicylaldehyde Thiosemicarbazone as an Ionophore

    Directory of Open Access Journals (Sweden)

    Sulekh Chandra

    2013-01-01

    Full Text Available A polymeric membrane-based tin selective electrode was developed by using salicylaldehyde thiosemicarbazone (STSC. The best performance was recorded with a membrane composition of PVC : TBP : ionophore : NaTPB as 28 : 59 : 8 : 5 (w/w%. The Nernstian slope calculated from the calibration curve for Sn2+ sensor was 28.8 ± 0.4 mV/decade. The detection limit of the sensor was 2.10 × 10−8 M, in the linear concentration range of 1.0 × 10−2−1.1 × 10−7 M. It was relatively fast response time (<8 s for concentration ≥1.0×10−4 and <12 s for concentration of ≥1.0×10−6 M and can be used for 9 months without any considerable divergence in potentials. The proposed sensor exhibit relatively good selectivity and high sensitivity for tin(II as other mono-, di-, and trivalent cations and can be used in a pH range of 2.0–8.5. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of stannous in artificially made samples.

  12. Quantum sensors based on single diamond defects

    International Nuclear Information System (INIS)

    Jelezko Fedor

    2014-01-01

    NV centers in diamond are promising sensors able to detect electric and magnetic fields at nanoscale. Here we report on the detection of biomolecules using magnetic noise induced by their electron and nuclear spins. Presented results show first steps towards establishing novel sensing technology for visualizing single proteins and study of their dynamics. (author)

  13. MIS-based sensors with hydrogen selectivity

    Science.gov (United States)

    Li,; Dongmei, [Boulder, CO; Medlin, J William [Boulder, CO; McDaniel, Anthony H [Livermore, CA; Bastasz, Robert J [Livermore, CA

    2008-03-11

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

  14. Optical Sensors based on Raman Effects

    DEFF Research Database (Denmark)

    Jernshøj, Kit Drescher

    Formålet med denne afhandling er at give en systematisk og uddybende videnskabelig diskussion af molekylær Raman spredning, som kan danne grundlag for udviklingen af molekylespecifikke optiske sensorer til on-site, ikke-destruktiv måling. Afhandlingen falder i tre dele, to teoriafsnit, hvor første...

  15. CVD-Graphene-Based Flexible, Thermoelectrochromic Sensor

    Directory of Open Access Journals (Sweden)

    Adam Januszko

    2017-01-01

    Full Text Available The main idea behind this work was demonstrated in a form of a new thermoelectrochromic sensor on a flexible substrate using graphene as an electrically reconfigurable thermal medium (TEChrom™. Our approach relies on electromodulation of thermal properties of graphene on poly(ethylene terephthalate (PET via mechanical destruction of a graphene layer. Graphene applied in this work was obtained by chemical vapor deposition (CVD technique on copper substrate and characterized by Raman and scanning tunneling spectroscopy. Electrical parameters of graphene were evaluated by the van der Pauw method on the transferred graphene layers onto SiO2 substrates by electrochemical delamination method. Two configurations of architecture of sensors, without and with the thermochromic layer, were investigated, taking into account the increase of voltage from 0 to 50 V and were observed by thermographic camera to define heat energy. Current-voltage characteristics obtained for the sensor with damaged graphene layer are linear, and the resistivity is independent from the current applied. The device investigated under 1000 W/m2 exhibited rise of resistivity along with increased temperature. Flexible thermoelectrochromic device with graphene presented here can be widely used as a sensor for both the military and civil monitoring.

  16. Amine-based solvents regeneration in gas-liquid membrane contactor based on asymmetric PVTMS

    NARCIS (Netherlands)

    Volkov, A.V.; Tsarkov, S.E.; Goetheer, E.L.V.; Volkov, V.V.

    2015-01-01

    Asymmetric flat-sheet membranes made of poly(vinyltrimethylsilane) (PVTMS) were studied for the regeneration of amine-based absorption solvents in a membrane gas-liquid contactor at 100°C. It was shown that PVTMS membrane possesses good mechanical and chemical stability in contact with 4 M

  17. Semiconductor Nanomembrane based Flight Sensors and Arrays, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA Phase I program would develop and demonstrate semiconductor nanomembrane (NM) based flight sensors and arrays on flexible substrates, using SOI (Silicon on...

  18. Applying Sensor-Based Technology to Improve Construction Safety Management.

    Science.gov (United States)

    Zhang, Mingyuan; Cao, Tianzhuo; Zhao, Xuefeng

    2017-08-11

    Construction sites are dynamic and complicated systems. The movement and interaction of people, goods and energy make construction safety management extremely difficult. Due to the ever-increasing amount of information, traditional construction safety management has operated under difficult circumstances. As an effective way to collect, identify and process information, sensor-based technology is deemed to provide new generation of methods for advancing construction safety management. It makes the real-time construction safety management with high efficiency and accuracy a reality and provides a solid foundation for facilitating its modernization, and informatization. Nowadays, various sensor-based technologies have been adopted for construction safety management, including locating sensor-based technology, vision-based sensing and wireless sensor networks. This paper provides a systematic and comprehensive review of previous studies in this field to acknowledge useful findings, identify the research gaps and point out future research directions.

  19. Copper(II)-selective membrane electrode based on a recently synthesized naphthol-derivative Schiff's base

    Energy Technology Data Exchange (ETDEWEB)

    Alizadeh, N.; Ershad, S. [Dept. of Chemistry, Tarbiat Moderres Univ., Tehran (Iran); Naeimi, H.; Sharghi, H. [Dept. of Chemistry, Shiraz Univ. (Iran); Shamsipur, M. [Dept. of Chemistry, Razi Univ., Kermanshah (Iran)

    1999-11-01

    A PVC membrane electrode for copper(II) ions based on a recently synthesized naphthol-derivative Schiff's base as membrane carrier was prepared. The sensor exhibits a Nernstian response for Cu{sup 2+} ions over a wide concentration range (5.0 x 10{sup -6}-5.0 x 10{sup -2} mol/L) with a detection limit of 3.1 x 10{sup -6} mol/L (0.2 {mu}g/mL). It has a very short response time of about 5 s and can be used for 3 months without any divergence in potential. The proposed electrode revealed good selectivities over a wide variety of other cations including alkali, alkaline earth, transition and heavy metal ions and could be used in a pH range of 4.0-7.0. It was successfully applied to the direct determination and potentiometric titration of copper ion. (orig.)

  20. Low Humidity Characteristics of Polymer-Based Capacitive Humidity Sensors

    OpenAIRE

    Majewski Jacek

    2017-01-01

    Polymer-based capacitive humidity sensors emerged around 40 years ago; nevertheless, they currently constitute large part of sensors’ market within a range of medium (climatic and industrial) humidity 20−80%RH due to their linearity, stability and cost-effectiveness. However, for low humidity values (0−20%RH) that type of sensor exhibits increasingly nonlinear characteristics with decreasing of humidity values. This paper presents the results of some experimental trials of CMOS polymer-based ...

  1. Gas Sensors Based on Polymer Field-Effect Transistors

    Directory of Open Access Journals (Sweden)

    Aifeng Lv

    2017-01-01

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

  2. Underwater Sensor Network Redeployment Algorithm Based on Wolf Search.

    Science.gov (United States)

    Jiang, Peng; Feng, Yang; Wu, Feng

    2016-10-21

    This study addresses the optimization of node redeployment coverage in underwater wireless sensor networks. Given that nodes could easily become invalid under a poor environment and the large scale of underwater wireless sensor networks, an underwater sensor network redeployment algorithm was developed based on wolf search. This study is to apply the wolf search algorithm combined with crowded degree control in the deployment of underwater wireless sensor networks. The proposed algorithm uses nodes to ensure coverage of the events, and it avoids the prematurity of the nodes. The algorithm has good coverage effects. In addition, considering that obstacles exist in the underwater environment, nodes are prevented from being invalid by imitating the mechanism of avoiding predators. Thus, the energy consumption of the network is reduced. Comparative analysis shows that the algorithm is simple and effective in wireless sensor network deployment. Compared with the optimized artificial fish swarm algorithm, the proposed algorithm exhibits advantages in network coverage, energy conservation, and obstacle avoidance.

  3. A Novel Interdigital Capacitor Pressure Sensor Based on LTCC Technology

    Directory of Open Access Journals (Sweden)

    Qiulin Tan

    2014-01-01

    Full Text Available A novel passive wireless pressure sensor is proposed based on LTCC (low temperature cofired ceramic technology. The sensor employs a passive LC circuit, which is composed of a variable interdigital capacitor and a constant inductor. The inductor and capacitor were fabricated by screen-printing. Pressure measurement is tested using a wireless mutual inductance coupling method. The experimental sensitivity of the sensor is about 273.95 kHz/bar below 2 bar. Experimental results show that the sensor can be read out wirelessly by external antenna at 600°C. The max readout distance is 3 cm at room temperature. The sensors described can be applied for monitoring of gas pressure in harsh environments, such as environment with high temperature and chemical corrosion.

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

    Energy Technology Data Exchange (ETDEWEB)

    Frigo, Janette Rose [Los Alamos National Laboratory; Brennan, Sean M [Los Alamos National Laboratory; Rosten, Edward J [Los Alamos National Laboratory; Raby, Eric Y [Los Alamos National Laboratory; Kulathumani, Vinod K [WEST VIRGINIA UNIV.

    2009-01-01

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

  5. Iodide-selective membrane electrode based on salophen complex of cobalt (III)

    OpenAIRE

    Zare,Hamid R.; Memarzadeh,Farkhondeh; Gorji,Alireza; Ardakani,Mohammad Mazloum

    2005-01-01

    A highly selective PVC membrane electrode based on a cobalt-salophen complex was prepared. The sensor displays an anti-Hofmeister selectivity sequence with a preference for iodide ion over many common anions. The electrode has a linear dynamic range between 5.0×10-7 to 1.0×10-1 mol L-1, with a Nernstian slope of -58.9 mV decade-1 and a detection limit of 3.0×10-7 mol L-1. The working pH range of the sensor is 3.1-9.8. It exhibits of a fast as 15 s and has a lifetime of about 2 months. The sel...

  6. Cobalt(II)-selective membrane electrode based on a recently synthesized benzo-substituted macrocyclic diamide.

    Science.gov (United States)

    Shamsipur, M; Poursaberi, T; Rouhani, S; Niknam, K; Sharghi, H; Ganjali, M R

    2001-09-01

    A PVC-membrane electrode based on a recently synthesized 18-membered macrocyclic diamide is presented. The electrode reveals a Nernstian potentiometric response for Co2+ over a wide concentration range (2.0 x 10(-6)-1.0 x 10(-2) M). The electrode has a response time of about 10 s and can be used for at least 2 months without any divergence. The proposed sensor revealed very good selectivities for Co2+ over a wide variety of other metal ions, and could be used over a wide pH range (3.0-8.0). The detection limit of the sensor is 6.0 x 10(-7) M. It was successfully applied to the direct determination and potentiometric titration of cobalt ion.

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

    Science.gov (United States)

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

    2016-01-18

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

  8. Graphene-based structure, method of suspending graphene membrane, and method of depositing material onto graphene membrane

    Science.gov (United States)

    Zettl, Alexander K.; Meyer, Jannik Christian

    2013-04-02

    An embodiment of a method of suspending a graphene membrane across a gap in a support structure includes attaching graphene to a substrate. A pre-fabricated support structure having the gap is attached to the graphene. The graphene and the pre-fabricated support structure are then separated from the substrate which leaves the graphene membrane suspended across the gap in the pre-fabricated support structure. An embodiment of a method of depositing material includes placing a support structure having a graphene membrane suspended across a gap under vacuum. A precursor is adsorbed to a surface of the graphene membrane. A portion of the graphene membrane is exposed to a focused electron beam which deposits a material from the precursor onto the graphene membrane. An embodiment of a graphene-based structure includes a support structure having a gap, a graphene membrane suspended across the gap, and a material deposited in a pattern on the graphene membrane.

  9. Membrane-based aberration-corrected tunable micro-lenses

    Science.gov (United States)

    Waibel, Philipp; Ermantraut, Eugen; Mader, Daniel; Zappe, Hans; Seifert, Andreas

    2010-05-01

    We present measurements and simulations of membrane-based micro-lens stacks, tunable in focal length in the range of 10mm to 50mm without chromatic aberration. The pressure-actuated, liquid-filled, membrane-based micro-lenses are fabricated by an all-silicone molding approach and consist of three chambers separated by two highly flexible silicone-membranes. Based on the idea of the classical achromatic Fraunhofer doublet, two different liquids with suitable optical properties are used. Pressure-dependent surface topologies are measured by profilometry for determining the correlation between refraction and applied pressure. The profiles are fit to polynomials; the coefficients of the polynomials are pressure-dependent and fit to empirically determined functions which are then used as an input for optical ray-tracing. Using this approach, the focal length is tunable while compensating for chromatic aberration by suitably applied pressures.

  10. Sensor-fusion-based biometric identity verification

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, J.J.; Bouchard, A.M.; Osbourn, G.C.; Martinez, R.F.; Bartholomew, J.W. [Sandia National Labs., Albuquerque, NM (United States); Jordan, J.B.; Flachs, G.M.; Bao, Z.; Zhu, L. [New Mexico State Univ., Las Cruces, NM (United States). Electronic Vision Research Lab.

    1998-02-01

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

  11. Flexible Piezoelectric Sensor-Based Gait Recognition

    Directory of Open Access Journals (Sweden)

    Youngsu Cha

    2018-02-01

    Full Text Available Most motion recognition research has required tight-fitting suits for precise sensing. However, tight-suit systems have difficulty adapting to real applications, because people normally wear loose clothes. In this paper, we propose a gait recognition system with flexible piezoelectric sensors in loose clothing. The gait recognition system does not directly sense lower-body angles. It does, however, detect the transition between standing and walking. Specifically, we use the signals from the flexible sensors attached to the knee and hip parts on loose pants. We detect the periodic motion component using the discrete time Fourier series from the signal during walking. We adapt the gait detection method to a real-time patient motion and posture monitoring system. In the monitoring system, the gait recognition operates well. Finally, we test the gait recognition system with 10 subjects, for which the proposed system successfully detects walking with a success rate over 93 %.

  12. Sensor-fusion-based biometric identity verification

    International Nuclear Information System (INIS)

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

    1998-02-01

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

  13. A Review of Microfiber-Based Temperature Sensors

    Directory of Open Access Journals (Sweden)

    Wanvisa Talataisong

    2018-02-01

    Full Text Available Optical microfiber-based temperature sensors have been proposed for many applications in a variety of industrial uses, including biomedical, geological, automotive, and defense applications. This increasing demand for these micrometric devices is attributed to their large dynamic range, high sensitivity, fast-response, compactness and robustness. Additionally, they can perform in-situ measurements remotely and in harsh environments. This paper presents an overview of optical microfibers, with a focus on their applications in temperature sensing. This review broadly divides microfiber-based temperature sensors into two categories: resonant and non-resonant microfiber sensors. While the former includes microfiber loop, knot and coil resonators, the latter comprises sensors based on functionally coated/doped microfibers, microfiber couplers, optical gratings and interferometers. In the conclusions, a summary of reported performances is presented.

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

    Directory of Open Access Journals (Sweden)

    Youngtae Jo

    2014-08-01

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

  15. Iodide selective membrane electrodes based on a Molybdenum-Salen as a neutral carrier

    Energy Technology Data Exchange (ETDEWEB)

    Ghanei-Motlagh, Masoud [Department of Chemistry, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Taher, Mohammad Ali, E-mail: ma_taher@yahoo.com [Department of Chemistry, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Ahmadi, Kyoumars [AJA University of Medical Sciences, Tehran (Iran, Islamic Republic of); Sheikhshoaie, Iran [Department of Chemistry, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of)

    2011-12-01

    A new polymeric membrane electrode (PME) and a coated platinum disk electrode (CPtE) based on Schiff base complex of Mo(VI) as a suitable carrier for I{sup -} ion were described. The influence of membrane composition, pH and possible interfering anions were investigated on the response properties of the electrodes. The electrodes exhibited a Nernstian slope of 63.0 {+-} 0.5 (CPtE) and 60.3 {+-} 0.4 (PME) mV decade{sup -1} in I{sup -} ion over a wide concentration range from 7.9 x 10{sup -7} to 1.0 x 10{sup -1} M for CPtE and 9.1 x 10{sup -6} to 1.0 x 10{sup -1} M I{sup -} for PME. The potentiometric response of the electrodes was independent of the pH of the test solution in the pH range 2.0-8.5 with a fast response time (< 10 s). The process of transfer of iodide across the membrane interface was investigated by use of the AC impedance technique. The proposed sensors were successfully applied to direct determination of iodide in samples containing interfering anions, waste water and as indicator electrodes in precipitation titrations. Highlights: {yields} We study new selective membrane electrodes for iodide ions. {yields} To the best of our knowledge this is the first coated platinum disk electrode of I{sup -}. {yields} The sensors have a wide concentration range with a fast response time. {yields} Efforts have been made to improve the selectivity with the use of CPtE.

  16. Colorimetric humidity sensor based on liquid composite materials for the monitoring of food and pharmaceuticals.

    Science.gov (United States)

    Bridgeman, Devon; Corral, Javier; Quach, Ashley; Xian, Xiaojun; Forzani, Erica

    2014-09-09

    Using supported ionic-liquid membrane (SILM)-inspired methodologies, we have synthesized, characterized, and developed a humidity sensor by coating a liquid composite material onto a hygroscopic, porous substrate. Similar to pH paper, the sensor responds to the environment's relative humidity and changes color accordingly. The humidity indicator is prepared by casting a few microliters of low-toxicity reagents on a nontoxic substrate. The sensing material is a newly synthesized liquid composite that comprises a hygroscopic medium for environmental humidity capture and a color indicator that translates the humidity level into a distinct color change. Sodium borohydride was used to form a liquid composite medium, and DenimBlu30 dye was used as a redox indicator. The liquid composite medium provides a hygroscopic response to the relative humidity, and DenimBlu30 translates the chemical changes into a visual change from yellow to blue. The borate-redox dye-based humidity sensor was prepared, and then Fourier transform infrared spectroscopy, differential scanning calorimetry, and image analysis methods were used to characterize the chemical composition, optimize synthesis, and gain insight into the sensor reactivity. Test results indicated that this new sensing material can detect relative humidity in the range of 5-100% in an irreversible manner with good reproducibility and high accuracy. The sensor is a low-cost, highly sensitive, easy-to-use humidity indicator. More importantly, it can be easily packaged with products to monitor humidity levels in pharmaceutical and food packaging.

  17. A Solar Position Sensor Based on Image Vision.

    Science.gov (United States)

    Ruelas, Adolfo; Velázquez, Nicolás; Villa-Angulo, Carlos; Acuña, Alexis; Rosales, Pedro; Suastegui, José

    2017-07-29

    Solar collector technologies operate with better performance when the Sun beam direction is normal to the capturing surface, and for that to happen despite the relative movement of the Sun, solar tracking systems are used, therefore, there are rules and standards that need minimum accuracy for these tracking systems to be used in solar collectors' evaluation. Obtaining accuracy is not an easy job, hence in this document the design, construction and characterization of a sensor based on a visual system that finds the relative azimuth error and height of the solar surface of interest, is presented. With these characteristics, the sensor can be used as a reference in control systems and their evaluation. The proposed sensor is based on a microcontroller with a real-time clock, inertial measurement sensors, geolocation and a vision sensor, that obtains the angle of incidence from the sunrays' direction as well as the tilt and sensor position. The sensor's characterization proved how a measurement of a focus error or a Sun position can be made, with an accuracy of 0.0426° and an uncertainty of 0.986%, which can be modified to reach an accuracy under 0.01°. The validation of this sensor was determined showing the focus error on one of the best commercial solar tracking systems, a Kipp & Zonen SOLYS 2. To conclude, the solar tracking sensor based on a vision system meets the Sun detection requirements and components that meet the accuracy conditions to be used in solar tracking systems and their evaluation or, as a tracking and orientation tool, on photovoltaic installations and solar collectors.

  18. Research on Bridge Sensor Validation Based on Correlation in Cluster

    Directory of Open Access Journals (Sweden)

    Huang Xiaowei

    2016-01-01

    Full Text Available In order to avoid the false alarm and alarm failure caused by sensor malfunction or failure, it has been critical to diagnose the fault and analyze the failure of the sensor measuring system in major infrastructures. Based on the real time monitoring of bridges and the study on the correlation probability distribution between multisensors adopted in the fault diagnosis system, a clustering algorithm based on k-medoid is proposed, by dividing sensors of the same type into k clusters. Meanwhile, the value of k is optimized by a specially designed evaluation function. Along with the further study of the correlation of sensors within the same cluster, this paper presents the definition and corresponding calculation algorithm of the sensor’s validation. The algorithm is applied to the analysis of the sensor data from an actual health monitoring system. The result reveals that the algorithm can not only accurately measure the failure degree and orientate the malfunction in time domain but also quantitatively evaluate the performance of sensors and eliminate error of diagnosis caused by the failure of the reference sensor.

  19. Advanced Taste Sensors Based on Artificial Lipids with Global Selectivity to Basic Taste Qualities and High Correlation to Sensory Scores

    Directory of Open Access Journals (Sweden)

    Yoshikazu Kobayashi

    2010-04-01

    Full Text Available Effective R&D and strict quality control of a broad range of foods, beverages, and pharmaceutical products require objective taste evaluation. Advanced taste sensors using artificial-lipid membranes have been developed based on concepts of global selectivity and high correlation with human sensory score. These sensors respond similarly to similar basic tastes, which they quantify with high correlations to sensory score. Using these unique properties, these sensors can quantify the basic tastes of saltiness, sourness, bitterness, umami, astringency and richness without multivariate analysis or artificial neural networks. This review describes all aspects of these taste sensors based on artificial lipid, ranging from the response principle and optimal design methods to applications in the food, beverage, and pharmaceutical markets.

  20. Advanced Taste Sensors Based on Artificial Lipids with Global Selectivity to Basic Taste Qualities and High Correlation to Sensory Scores

    Science.gov (United States)

    Kobayashi, Yoshikazu; Habara, Masaaki; Ikezazki, Hidekazu; Chen, Ronggang; Naito, Yoshinobu; Toko, Kiyoshi

    2010-01-01

    Effective R&D and strict quality control of a broad range of foods, beverages, and pharmaceutical products require objective taste evaluation. Advanced taste sensors using artificial-lipid membranes have been developed based on concepts of global selectivity and high correlation with human sensory score. These sensors respond similarly to similar basic tastes, which they quantify with high correlations to sensory score. Using these unique properties, these sensors can quantify the basic tastes of saltiness, sourness, bitterness, umami, astringency and richness without multivariate analysis or artificial neural networks. This review describes all aspects of these taste sensors based on artificial lipid, ranging from the response principle and optimal design methods to applications in the food, beverage, and pharmaceutical markets. PMID:22319306

  1. Poly(4-vinyl pyridine) radiografted PVDF track etched membranes as sensors for monitoring trace mercury in water

    Science.gov (United States)

    Bessbousse, H.; Zran, N.; Fauléau, J.; Godin, B.; Lemée, V.; Wade, T.; Clochard, M.-C.

    2016-01-01

    By a radiation-induced grafting technique, we have functionalized track-etched nanoporous polymer membranes with mercury sensitive poly-4-vinyl pyridine (P4VP). Coating of these membranes with a very thin layer of gold results in an electrochemical sensor that is very selective and highly sensitive for mercury LOD 5 ng/L - well below the norms for water (0.015 μg/L potable water and 0.5 μg/L residual waters-French water norms of 27 October 2011). E-beam irradiation permitted optimization of the radiografting synthesis on PVDF thin films prior to ion-track grafting. Synthesis and characterization by EPR, FESEM and FTIR are described in detail. A comparison between FTIR in ATR and transmission modes enabled us to localize the grafting on the surface of the e-beam irradiated PVDF films allowing us to extrapolate what happens on the etched tracks. Using Square Wave Anodic Stripping Voltammetry (SW-ASV), mercury concentrations of 1 μg/L are detected in 2 h and low ng/L concentrations are detected after 24 h of adsorption. The adsorption is passive so sensors do not require instrumentation and the analysis takes only 3-4 min. Also, the P4VP functionalized sensor appears insensitive to pH variations (pHs 3-9), high salt concentrations (up to 1 g/L) and the presence of other heavy metals in the same solution.

  2. Chemical sensors based on molecularly modified metallic nanoparticles

    International Nuclear Information System (INIS)

    Haick, Hossam

    2007-01-01

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

  3. Compact IR laser for calibration of space based sensors

    Energy Technology Data Exchange (ETDEWEB)

    Kietrick, K.M.; Dezenberg, G. [Army Space and Strategic Defense Command, Huntsville, AL (United States); Hamilton, C. [Aculight Corp., Bellevue, WA (United States); Vann, J.; LaSala, J.

    1996-04-17

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

  4. Calibration system of underwater robot sensor based on CID algorithm

    Science.gov (United States)

    Wang, Xiaolong; Wang, Sen; Gao, Lifu; Wu, Shan; Wei, Shuheng

    2017-06-01

    In the calibration of static characteristic of the sensor, the original measured data are usually a nonlinear distribution. Based on this situation, underwater robot sensor static calibration system is designed. The system consists of four parts: a sensor, I-V conversion with amplifying circuit, microcontroller STM32F107 and a PC. The lower computer and the upper computer communicate by USB. A kind of adaptive cyclic iterative denoising (CID) algorithm is presented for data processing. Finally the curve will be fitted with compensation processing.

  5. Highly Sensitive Flexible Magnetic Sensor Based on Anisotropic Magnetoresistance Effect.

    Science.gov (United States)

    Wang, Zhiguang; Wang, Xinjun; Li, Menghui; Gao, Yuan; Hu, Zhongqiang; Nan, Tianxiang; Liang, Xianfeng; Chen, Huaihao; Yang, Jia; Cash, Syd; Sun, Nian-Xiang

    2016-11-01

    A highly sensitive flexible magnetic sensor based on the anisotropic magnetoresistance effect is fabricated. A limit of detection of 150 nT is observed and excellent deformation stability is achieved after wrapping of the flexible sensor, with bending radii down to 5 mm. The flexible AMR sensor is used to read a magnetic pattern with a thickness of 10 μm that is formed by ferrite magnetic inks. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. submitter Linear encoder based low frequency inertial sensor

    CERN Document Server

    Hellegouarch, Sylvain; Artoos, Kurt; Lambert, Pierre; Collette, Christophe

    2016-01-01

    In this article, we present a novel concept of inertial sensor, based on a linear encoder. Compared to other interferometric sensors, the encoder is much more easy to mount, and the calibration more stable. A prototype has been built and validated experimentally by comparison with a commercial seismometer. It has a resolution of about 10 pm/√Hz. In order to further improve the resolution, two concepts of mechanical amplifiers have been studied and compared. One of them is shown to be extremely promising, provided that the amplifier does not stiffen the sensor.

  7. Nanostructured Polypyrrole-Based Ammonia and Volatile Organic Compound Sensors

    Directory of Open Access Journals (Sweden)

    Milena Šetka

    2017-03-01

    Full Text Available The aim of this review is to summarize the recent progress in the fabrication of efficient nanostructured polymer-based sensors with special focus on polypyrrole. The correlation between physico-chemical parameters, mainly morphology of various polypyrrole nanostructures, and their sensitivity towards selected gas and volatile organic compounds (VOC is provided. The different approaches of polypyrrole modification with other functional materials are also discussed. With respect to possible sensors application in medicine, namely in the diagnosis of diseases via the detection of volatile biomarkers from human breath, the sensor interaction with humidity is described as well. The major attention is paid to analytes such as ammonia and various alcohols.

  8. Aquaporin-Based Biomimetic Polymeric Membranes: Approaches and Challenges

    Science.gov (United States)

    Habel, Joachim; Hansen, Michael; Kynde, Søren; Larsen, Nanna; Midtgaard, Søren Roi; Jensen, Grethe Vestergaard; Bomholt, Julie; Ogbonna, Anayo; Almdal, Kristoffer; Schulz, Alexander; Hélix-Nielsen, Claus

    2015-01-01

    In recent years, aquaporin biomimetic membranes (ABMs) for water separation have gained considerable interest. Although the first ABMs are commercially available, there are still many challenges associated with further ABM development. Here, we discuss the interplay of the main components of ABMs: aquaporin proteins (AQPs), block copolymers for AQP reconstitution, and polymer-based supporting structures. First, we briefly cover challenges and review recent developments in understanding the interplay between AQP and block copolymers. Second, we review some experimental characterization methods for investigating AQP incorporation including freeze-fracture transmission electron microscopy, fluorescence correlation spectroscopy, stopped-flow light scattering, and small-angle X-ray scattering. Third, we focus on recent efforts in embedding reconstituted AQPs in membrane designs that are based on conventional thin film interfacial polymerization techniques. Finally, we describe some new developments in interfacial polymerization using polyhedral oligomeric silsesquioxane cages for increasing the physical and chemical durability of thin film composite membranes. PMID:26264033

  9. Ultrasensitive, Stretchable Strain Sensors Based on Fragmented Carbon Nanotube Papers

    KAUST Repository

    Zhou, Jian

    2017-01-17

    The development of strain sensors featuring both ultra high sensitivity and high stretchability is still a challenge. We demonstrate that strain sensors based on fragmented single-walled carbon nanotube (SWCNT) paper embedded in poly(dimethylsiloxane) (PDMS) can sustain their sensitivity even at very high strain levels (with a gauge factor of over 10(7) at 50% strain). This record sensitivity is ascribed to the low initial electrical resistance (5-28 Omega) of the SWCNT paper and the wide change in resistance (up to 10(6) Omega) governed by the percolated network of SWCNT in the cracked region. The sensor response remains nearly unchanged after 10 000 strain cycles at 20% proving the robustness of this technology. This fragmentation based sensing system brings opportunities to engineer highly sensitive stretchable sensors.

  10. Laboratory test of an APS-based sun sensor prototype

    Science.gov (United States)

    Rufino, Giancarlo; Perrotta, Alessandro; Grassi, Michele

    2017-11-01

    This paper deals with design and prototype development of an Active Pixel Sensor - based miniature sun sensor and a laboratory facility for its indoor test and calibration. The miniature sun sensor is described and the laboratory test facility is presented in detail. The major focus of the paper is on tests and calibration of the sensor. Two different calibration functions have been adopted. They are based, respectively, on a geometrical model, which has required least-squares optimisation of system physical parameters estimates, and on neural networks. Calibration results are presented for the above solutions, showing that accuracy in the order of 0.01° has been achieved. Neural calibration functions have attained better performance thanks to their intrinsic auto-adaptive structure.

  11. A high sensitivity nanomaterial based SAW humidity sensor

    Energy Technology Data Exchange (ETDEWEB)

    Wu, T-T; Chou, T-H [Institute of Applied Mechanics, National Taiwan University, Taipei 106, Taiwan (China); Chen, Y-Y [Department of Mechanical Engineering, Tatung University, Taipei 104, Taiwan (China)], E-mail: wutt@ndt.iam.ntu.edu.tw

    2008-04-21

    In this paper, a highly sensitive humidity sensor is reported. The humidity sensor is configured by a 128{sup 0}YX-LiNbO{sub 3} based surface acoustic wave (SAW) resonator whose operating frequency is at 145 MHz. A dual delay line configuration is realized to eliminate external temperature fluctuations. Moreover, for nanostructured materials possessing high surface-to-volume ratio, large penetration depth and fast charge diffusion rate, camphor sulfonic acid doped polyaniline (PANI) nanofibres are synthesized by the interfacial polymerization method and further deposited on the SAW resonator as selective coating to enhance sensitivity. The humidity sensor is used to measure various relative humidities in the range 5-90% at room temperature. Results show that the PANI nanofibre based SAW humidity sensor exhibits excellent sensitivity and short-term repeatability.

  12. Schiff bases as cadmium(II) selective ionophores in polymeric membrane electrodes

    International Nuclear Information System (INIS)

    Gupta, V.K.; Singh, A.K.; Gupta, Barkha

    2007-01-01

    The construction and performance characteristics of polymeric membrane electrodes based on two neutral ionophores, N,N'-[bis(pyridin-2-yl)formylidene]butane-1,4-diamine (S 1 ) and N-(2-pyridinylmethylene)-1,2-benzenediamine (S 2 ) for quantification of cadmium ions, are described. The influences of membrane compositions on the potentiometric response of the electrodes have been found to substantially improve the performance characteristics. The best performance was obtained with the electrode having a membrane composition (w/w) of (S 1 ) (2.15%):PVC (32.2%):o-NPOE (64.5%):KTpClPB (1.07%). The proposed electrode exhibits Nernstian response in the concentration range of 7.9 x 10 -8 to 1.0 x 10 -1 M Cd 2+ with limit of detection 5.0 x 10 -8 M, performs satisfactorily over wide pH range (2.0-8.0) with a fast response time (10 s). The sensor has been found to work satisfactorily in partially non-aqueous media up to 30% (v/v) content of methanol, ethanol and acetonitrile and could be used for a period of 2 months. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of cadmium in real samples. The practical utility of the membrane electrode has also been observed in the presence of surfactants

  13. Schiff bases as cadmium(II) selective ionophores in polymeric membrane electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, V.K. [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India)]. E-mail: vinodfcy@iitr.ernet.in; Singh, A.K. [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India); Gupta, Barkha [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India)

    2007-02-05

    The construction and performance characteristics of polymeric membrane electrodes based on two neutral ionophores, N,N'-[bis(pyridin-2-yl)formylidene]butane-1,4-diamine (S{sub 1}) and N-(2-pyridinylmethylene)-1,2-benzenediamine (S{sub 2}) for quantification of cadmium ions, are described. The influences of membrane compositions on the potentiometric response of the electrodes have been found to substantially improve the performance characteristics. The best performance was obtained with the electrode having a membrane composition (w/w) of (S{sub 1}) (2.15%):PVC (32.2%):o-NPOE (64.5%):KTpClPB (1.07%). The proposed electrode exhibits Nernstian response in the concentration range of 7.9 x 10{sup -8} to 1.0 x 10{sup -1} M Cd{sup 2+} with limit of detection 5.0 x 10{sup -8} M, performs satisfactorily over wide pH range (2.0-8.0) with a fast response time (10 s). The sensor has been found to work satisfactorily in partially non-aqueous media up to 30% (v/v) content of methanol, ethanol and acetonitrile and could be used for a period of 2 months. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of cadmium in real samples. The practical utility of the membrane electrode has also been observed in the presence of surfactants.

  14. Mercury(II) selective sensors based on AlGaN/GaN transistors

    Energy Technology Data Exchange (ETDEWEB)

    Asadnia, Mohsen, E-mail: mohsen.asadnia@mq.edu.au [School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009 (Australia); Department of Engineering, Macquarie University, NSW 2109 (Australia); Myers, Matthew [School of Chemistry and Biochemistry, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009 (Australia); CSIRO Energy Flagship, Kensington, Western Australia 6151 (Australia); Akhavan, N.D. [School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009 (Australia); O' Donnell, Kane [Department of Imaging and Applied Physics, Curtin University, Bentley, Western Australia 6102 (Australia); Umana-Membreno, Gilberto A. [School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009 (Australia); Mishra, U.K. [Electrical and Computer Engineering Department, University of California, Santa Barbara, CA 93106 (United States); Nener, Brett [School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009 (Australia); Baker, Murray [School of Chemistry and Biochemistry, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009 (Australia); Parish, Giacinta [School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009 (Australia)

    2016-11-02

    This work presents the first polymer approach to detect metal ions using AlGaN/GaN transistor-based sensor. The sensor utilised an AlGaN/GaN high electron mobility transistor-type structure by functionalising the gate area with a polyvinyl chloride (PVC) based ion selective membrane. Sensors based on this technology are portable, robust and typically highly sensitive to the target analyte; in this case Hg{sup 2+}. This sensor showed a rapid and stable response when it was introduced to solutions of varying Hg{sup 2+} concentrations. At pH 2.8 in a 10{sup −2} M KNO{sub 3} ion buffer, a detection limit below 10{sup −8} M and a linear response range between 10{sup −8} M-10{sup −4} M were achieved. This detection limit is an order of magnitude lower than the reported detection limit of 10{sup −7} M for thioglycolic acid monolayer functionalised AlGaN/GaN HEMT devices. Detection limits of approximately 10{sup −7} M and 10{sup −6} M in 10{sup −2} M Cd(NO{sub 3}){sub 2} and 10{sup −2} M Pb(NO{sub 3}){sub 2} ion buffers were also achieved, respectively. Furthermore, we show that the apparent gate response was near-Nernstian under various conditions. X-ray photoelectron spectroscopy (XPS) experiments confirmed that the sensing membrane is reversible after being exposed to Hg{sup 2+} solution and rinsed with deionised water. The success of this study precedes the development of this technology in selectively sensing multiple ions in water with use of the appropriate polymer based membranes on arrays of devices. - Highlights: • This work is the first polymer approach to detect metal ions using AlGaN/GaN transistor-based sensor. • The sensor utilised an AlGaN/GaN transistor by functionalising the gate area with a polyvinyl chloride (PVC) based membrane. • The sensor showed a rapid and linear response between 10{sup −8} M-10{sup −4} M for Hg{sup 2+} detection at pH 2.8 in a 10{sup −2} M KNO{sub 3} ion buffer. • Detection limits of

  15. Novel gas sensors based on carbon nanotube networks

    International Nuclear Information System (INIS)

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

    2008-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Zhenzhong Guo

    2016-10-01

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

  17. Force sensors based on screen-printed cantilevers

    OpenAIRE

    Lakhmi, Riadh; Debéda, Hélène; Dufour, Isabelle; Lucat, Claude

    2010-01-01

    International audience; In this paper, the design, the fabrication and the characterization of ceramic screen-printed force sensors aredescribed. They are based on the use of cantilevers with integrated piezoresistors. The choice of the materials constitutingthe cantilever and the strain gauge, so as the dimensions of the cantilever have been optimized in order to measure forces in mNrange. The sensors have been fabricated using the screenprinting technique associated with the sacrificial lay...

  18. A Calibration Report for Wireless Sensor-Based Weatherboards

    Directory of Open Access Journals (Sweden)

    Muthoni Masinde

    2015-03-01

    Full Text Available Sub-Saharan Africa contains the highest number of people affected by droughts. Although this can easily be mitigated through the provision of timely, reliable and relevant weather forecasts, the sparse network of weather stations in most of these countries makes this difficult. Rapid development in wireless sensor networks has resulted in weatherboards capable of capturing weather parameters at the micro-level. Although these weatherboards offer a viable solution to Africa’s drought, the acceptability of such data by meteorologists is only possible if these sensors are calibrated and their field readiness scientifically evaluated. This is the contribution of this paper; we present results of a calibration exercise that was carried out to: (1 measure and correct lag, random and systematic errors; (2 determine if Perspex was an ideal material for building sensor boards’ enclosures; and (3 identify sensor boards’ battery charging and depletion rates. The result is a calibration report detailing actual error and uncertainty values for atmospheric pressure, humidity and temperature sensors, as well as the recharge and discharge curves of the batteries. The results further ruled out the use of Perspex for enclosing the sensor boards. These experiments pave the way for the design and implementation of a sensor-based weather monitoring system (SenseWeather that was piloted in two regions in Kenya.

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Carlos Morón

    2015-11-01

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

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

    Science.gov (United States)

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

    2015-11-11

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

  2. A Review of Carbon Nanotubes-Based Gas Sensors

    Directory of Open Access Journals (Sweden)

    Yun Wang

    2009-01-01

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

  3. Inertial Sensor-Based Gait Recognition: A Review

    Science.gov (United States)

    Sprager, Sebastijan; Juric, Matjaz B.

    2015-01-01

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

  4. Microfluidic sensors based on perforated cantilevers

    DEFF Research Database (Denmark)

    Noeth, Nadine-Nicole

    Arbejdet presenteret i denne PhD afhandling omhandler udviklingen af en mikrofluide sensor basered på bjælke teknologi. Bjælkerne er fremstillet i den negative photo-resist SU-8 og i SiN. I bjælkerne er der inkorporeret et array af huller. To nye sensorer er udviklet på baggrund af de perforerede...... bjælker: en yderst sensitiv flow-meter og en partikel tæller med integreret filter funktion. En optisk udlæsningsteknik benyttes til at måle udbøjningen af bjælkerne. En laser stråle fokuseres på enden af bjælken og bjælke forskydningen måles ved at detekterer laser strålens forskydning ved hjælp af en...... muligt at separerer og tæller partikler af forskellig størrelse. Uden PhD projektet er der designet mikrochips der muliggør en billig og hurtig fremstilling af systemer som beskrevet ovenfor med et meget højt udbytte. For disse mikrochips er der opnået et godt optisk signal for målinger i væske. Ydermere...

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

    Science.gov (United States)

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

    2014-11-01

    Nanomaterial-based surface-enhanced Raman scattering (SERS) sensors are highly promising analytical tools, capable of ultrasensitive, multiplex, and nondestructive detection of chemical and biological species. Extensive efforts have been made to design various silicon nanohybrid-based SERS substrates such as gold/silver nanoparticle (NP)-decorated silicon nanowires, Au/Ag NP-decorated silicon wafers (AuNP@Si), and so forth. In comparison to free AuNP- and AgNP-based SERS sensors, the silicon nanohybrid-based SERS sensors feature higher enhancement factors (EFs) and excellent reproducibility, since SERS hot spots are efficiently coupled and stabilized through interconnection to the semiconducting silicon substrates. Consequently, in the past decade, giant advancements in the development of silicon nanohybrid-based SERS sensors have been witnessed for myriad sensing applications. In this review, the representative achievements related to the design of high-performance silicon nanohybrid-based SERS sensors and their use for chemical and biological analysis are reviewed in a detailed way. Furthermore, the major opportunities and challenges in this field are discussed from a broad perspective and possible future directions. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Electrochemical sensors and biosensors based on less aggregated graphene.

    Science.gov (United States)

    Bo, Xiangjie; Zhou, Ming; Guo, Liping

    2017-03-15

    As a novel single-atom-thick sheet of sp 2 hybridized carbon atoms, graphene (GR) has attracted extensive attention in recent years because of its unique and remarkable properties, such as excellent electrical conductivity, large theoretical specific surface area, and strong mechanical strength. However, due to the π-π interaction, GR sheets are inclined to stack together, which may seriously degrade the performance of GR with the unique single-atom layer. In recent years, an increasing number of GR-based electrochemical sensors and biosensors are reported, which may reflect that GR has been considered as a kind of hot and promising electrode material for electrochemical sensor and biosensor construction. However, the active sites on GR surface induced by the irreversible GR aggregations would be deeply secluded inside the stacked GR sheets and therefore are not available for the electrocatalysis. So the alleviation or the minimization of the aggregation level for GR sheets would facilitate the exposure of active sites on GR and effectively upgrade the performance of GR-based electrochemical sensors and biosensors. Less aggregated GR with low aggregation and high dispersed structure can be used in improving the electrochemical activity of GR-based electrochemical sensors or biosensors. In this review, we summarize recent advances and new progress for the development of electrochemical sensors based on less aggregated GR. To achieve such goal, many strategies (such as the intercalation of carbon materials, surface modification, and structural engineering) have been applied to alleviate the aggregation level of GR in order to enhance the performance of GR-based electrochemical sensors and biosensors. Finally, the challenges associated with less aggregated GR-based electrochemical sensors and biosensors as well as related future research directions are discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. A Solar Position Sensor Based on Image Vision

    Directory of Open Access Journals (Sweden)

    Adolfo Ruelas

    2017-07-01

    Full Text Available Solar collector technologies operate with better performance when the Sun beam direction is normal to the capturing surface, and for that to happen despite the relative movement of the Sun, solar tracking systems are used, therefore, there are rules and standards that need minimum accuracy for these tracking systems to be used in solar collectors’ evaluation. Obtaining accuracy is not an easy job, hence in this document the design, construction and characterization of a sensor based on a visual system that finds the relative azimuth error and height of the solar surface of interest, is presented. With these characteristics, the sensor can be used as a reference in control systems and their evaluation. The proposed sensor is based on a microcontroller with a real-time clock, inertial measurement sensors, geolocation and a vision sensor, that obtains the angle of incidence from the sunrays’ direction as well as the tilt and sensor position. The sensor’s characterization proved how a measurement of a focus error or a Sun position can be made, with an accuracy of 0.0426° and an uncertainty of 0.986%, which can be modified to reach an accuracy under 0.01°. The validation of this sensor was determined showing the focus error on one of the best commercial solar tracking systems, a Kipp & Zonen SOLYS 2. To conclude, the solar tracking sensor based on a vision system meets the Sun detection requirements and components that meet the accuracy conditions to be used in solar tracking systems and their evaluation or, as a tracking and orientation tool, on photovoltaic installations and solar collectors.

  8. Deoxycholate-Based Glycosides (DCGs) for Membrane Protein Stabilisation

    DEFF Research Database (Denmark)

    Bae, Hyoung Eun; Gotfryd, Kamil; Thomas, Jennifer

    2015-01-01

    reported deoxycholate-based N-oxides (DCAOs). Membrane proteins in these agents, particularly the branched diglucoside-bearing amphiphiles DCG-1 and DCG-2, displayed favourable behaviour compared to previously reported parent compounds (DCAOs) and conventional detergents (LDAO and DDM). Given...

  9. based anion exchange membrane for alkaline polymer electrolyte

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Hydroxyl ion (OH–) conducting anion exchange membranes based on modified poly (phenylene oxide) are fabricated for their application in alkaline polymer electrolyte fuel cells (APEFCs). In the present study, chloromethylation of poly(phenylene oxide) (PPO) is performed by aryl substitution rather than benzyl.

  10. Fullerene and dendrimer based nano-composite gas separation membranes

    NARCIS (Netherlands)

    Sterescu, D.M.

    2007-01-01

    This thesis describes the development of new materials for membrane based gas separation processes. Long-term stable, loosely packed (high free volume) amorphous polymer films were prepared by introduction of super-molecular pendant groups, which possess hardsphere properties to avoid dense

  11. Sulfonated carbon black-based composite membranes for fuel cell ...

    Indian Academy of Sciences (India)

    Sci., Vol. 36, No. 4, August 2013, pp. 563–573. c Indian Academy of Sciences. Sulfonated carbon black-based composite membranes for fuel cell applications .... All data were collected from a second heating cycle and glass tran- sition temperatures (Tg) were calculated as a midpoint of thermogram. 2.5d FTIR studies: FTIR ...

  12. Potentiometric measurement of polymer-membrane electrodes based on lanthanum

    International Nuclear Information System (INIS)

    Saefurohman, Asep; Buchari,; Noviandri, Indra; Syoni

    2014-01-01

    Quantitative analysis of rare earth elements which are considered as the standard method that has a high accuracy, and detection limits achieved by the order of ppm is inductively coupled plasma atomic emission spectroscopy (ICPAES). But these tools are expensive and valuable analysis of the high cost of implementation. In this study be made and characterized selective electrode for the determination of rare earth ions is potentiometric. Membrane manufacturing techniques studied is based on immersion (liquid impregnated membrane) in PTFE 0.5 pore size. As ionophores to be used tri butyl phosphate (TBP) and bis(2-etylhexyl) hydrogen phosphate. There is no report previously that TBP used as ionophore in polymeric membrane based lanthanum. Some parameters that affect the performance of membrane electrode such as membrane composition, membrane thickness, and types of membrane materials studied in this research. Manufacturing of Ion Selective Electrodes (ISE) Lanthanum (La) by means of impregnation La membrane in TBP in kerosene solution has been done and showed performance for ISE-La. FTIR spectrum results for PTFE 0.5 pore size which impregnated in TBP and PTFE blank showed difference of spectra in the top 1257 cm −1 , 1031 cm −1 and 794.7 cm −1 for P=O stretching and stretching POC from group −OP =O. The result showed shift wave number for P =O stretching of the cluster (−OP=O) in PTFE-TBP mixture that is at the peak of 1230 cm −1 indicated that no interaction bond between hydroxyl group of molecules with molecular clusters fosforil of TBP or R 3 P = O. The membrane had stable responses in pH range between 1 and 9. Good responses were obtained using 10 −3 M La(III) internal solution, which produced relatively high potential. ISE-La showed relatively good performances. The electrode had a response time of 29±4.5 second and could be use for 50 days. The linear range was between 10 −5 and 10 −1 M

  13. Gas Sensors Based on Ceramic p-n Heterocontacts

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-01-01

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

  14. Optical Enzyme Sensor for Urea Determination via Immobilized pH Indicator and Urease onto Transparent Membranes

    Directory of Open Access Journals (Sweden)

    Milka Krysteva

    2003-01-01

    Full Text Available Transparent triacetylcellulose membranes with immobilized pH indicator (neutral red as well as with simultaneously immobilized urease and neutral red were used as optical sensors for determination of urea concentrations in model solutions. Decomposition of urea with the enzyme urease is accompanied by evolution of ammonia. This leads to the changes of the neutral red absorption, which is proportional to the substrate (urea within certain concentration limits in model solution. As a result of the investigation, standard curves were plotted for determination of urea over the range of 1 to 500 mM using immobilized indicator and free urease. Simultaneous immobilization of indicator and urease permitted determination of urea in the interval 50 to 500 mM. The membrane used contained 0.169 U urease activity on an area of 1.7 cm2. The standard curves were plotted using the linear region of the kinetic curves for the corresponding substrate concentrations. A possible scheme of the interaction between the activated triacetylcellulose membrane and the indicator and enzyme is proposed. The membranes obtained are suitable for repeated ecological applications where urea is to be determined.

  15. A Potentiometric Indirect Uric Acid Sensor Based on ZnO Nanoflakes and Immobilized Uricase

    Science.gov (United States)

    Usman Ali, Syed M.; Ibupoto, Zafar Hussain; Kashif, Muhammad; Hashim, Uda; Willander, Magnus

    2012-01-01

    In the present work zinc oxide nanoflakes (ZnO-NF) structures with a wall thickness around 50 to 100 nm were synthesized on a gold coated glass substrate using a low temperature hydrothermal method. The enzyme uricase was electrostatically immobilized in conjunction with Nafion membrane on the surface of well oriented ZnO-NFs, resulting in a sensitive, selective, stable and reproducible uric acid sensor. The electrochemical response of the ZnO-NF-based sensor vs. a Ag/AgCl reference electrode was found to be linear over a relatively wide logarithmic concentration range (500 nM to 1.5 mM). In addition, the ZnO-NF structures demonstrate vast surface area that allow high enzyme loading which results provided a higher sensitivity. The proposed ZnO-NF array-based sensor exhibited a high sensitivity of ∼66 mV/ decade in test electrolyte solutions of uric acid, with fast response time. The sensor response was unaffected by normal concentrations of common interferents such as ascorbic acid, glucose, and urea. PMID:22736977

  16. A droplet-based passive force sensor for remote tactile sensing applications

    Science.gov (United States)

    Nie, Baoqing; Yao, Ting; Zhang, Yiqiu; Liu, Jian; Chen, Xinjian

    2018-01-01

    A droplet-based flexible wireless force sensor has been developed for remote tactile-sensing applications. By integration of a droplet-based capacitive sensing unit and two circular planar coils, this inductor-capacitor (LC) passive sensor offers a platform for the mechanical force detection in a wireless transmitting mode. Under external loads, the membrane surface of the sensor deforms the underlying elastic droplet uniformly, introducing a capacitance response in tens of picofarads. The LC circuit transduces the applied force into corresponding variations of its resonance frequency, which is detected by an external electromagnetic coupling coil. Specifically, the liquid droplet features a mechanosensitive plasticity, which results in an increased device sensitivity as high as 2.72 MHz N-1. The high dielectric property of the droplet endows our sensor with high tolerance for noise and large capacitance values (20-40 pF), the highest value in the literature for the LC passive devices in comparable dimensions. It achieves excellent reproducibility under periodical loads ranging from 0 to 1.56 N and temperature fluctuations ranging from 10 °C to 55 °C. As an interesting conceptual demonstration, the flexible device has been configured into a fingertip-amounted setting in a highly compact package (of 11 mm × 11 mm × 0.25 mm) for remote contact force sensing in the table tennis game.

  17. Carbon Nano tubes Based Mixed Matrix Membrane for Gas Separation

    International Nuclear Information System (INIS)

    Sanip, S.M.; Ismail, A.F.; Goh, P.S.; Norrdin, M.N.A.; Soga, T.; Tanemura, M.; Yasuhiko, H.

    2011-01-01

    Carbon nano tubes based mixed matrix membrane (MMM) was prepared by the solution casting method in which the functionalized multi walled carbon nano tubes (f-MWNTs) were embedded into the polyimide membrane and the resulting membranes were characterized. The effect of nominal MWNTs content between 0.5 and 1.0 wt % on the gas separation properties were looked into. The morphologies of the MMM also indicated that at 0.7 % loading of f- MWNTs, the structures of the MMM showed uniform finger-like structures which have facilitated the fast gas transport through the polymer matrix. It may also be concluded that addition of open ended and shortened MWNTs to the polymer matrix can improve its permeability by increasing diffusivity through the MWNTs smooth cavity. (author)

  18. A sensitive, handheld vapor sensor based on microcantilevers

    Science.gov (United States)

    Pinnaduwage, L. A.; Hedden, D. L.; Gehl, A.; Boiadjiev, V. I.; Hawk, J. E.; Farahi, R. H.; Thundat, T.; Houser, E. J.; Stepnowski, S.; McGill, R. A.; Deel, L.; Lareau, R. T.

    2004-11-01

    We report the development of a handheld sensor based on piezoresistive microcantilevers that does not depend on optical detection, yet has high detection sensitivity. The sensor is able to detect vapors from the plastic explosives pentaerythritol tetranitrate and hexahydro-1,3,5-triazine at levels below 10 parts per trillion within few seconds of exposure under ambient conditions. A differential measurement technique has yielded a rugged sensor that is unaffected by vibration and is able to function as a "sniffer." The microelectromechanical system sensor design allows for the incorporation of hundreds of microcantilevers with suitable coatings in order to achieve sufficient selectivity in the future, and thus could provide an inexpensive, unique platform for the detection of chemical, biological, and explosive materials.

  19. An Architecture for Intelligent Systems Based on Smart Sensors

    Science.gov (United States)

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

    2004-01-01

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

  20. Impedance-based damage assessment using piezoelectric sensors

    Science.gov (United States)

    Rim, Mi-Sun; Yoo, Seung-Jae; Lee, In; Song, Jae-Hoon; Yang, Jae-Won

    2011-04-01

    Recently structural health monitoring (SHM) systems are being focused because they make it possible to assess the health of structures at real-time in many application fields such as aircraft, aerospace, civil and so on. Piezoelectric materials are widely used for sensors of SHM system to monitor damage of critical parts such as bolted joints. Bolted joints could be loosened by vibration, thermal cycling, shock, corrosion, and they cause serious mechanical failures. In this paper, impedance-based method using piezoelectric sensors was applied for real-time SHM. A steel beam specimen fastened by bolts was tested, and polymer type piezoelectric materials, PVDFs were used for sensors to monitor the condition of bolted joint connections. When structure has some damage, for example loose bolts, the impedance of PVDF sensors showed different tendency with normal structure which has no loose bolts. In the case of loose bolts, impedance values are decreased and admittance values are increased.

  1. Optical Fibre Temperature Sensor Based On A Blackbody Radiation

    Science.gov (United States)

    Hypszer, Ryszard; Plucinski, Jerzy; Wierzba, Henryk J.

    1990-01-01

    The principle of operation of the fibre optical temperature sensor based on a blackbody radiation and its construction model is given in the paper. A quartz rod of 0.6 mm diameter and 20 cm length with a blackbody cavity at the one end was used to construct the sensor. The cavity was made by vacuum evaporation of a chromium layer and a silicone monooxide layer was used as a protection. Infrared radiation is transmitted by the fibre optic to the detection circuit. This sensor enables temperature measurement from 400 to 1200°C. The range of measurement is determined by the detection sensitivity and by rod softening. The resolution is of the order of 10-2°C. The sensor calibration was done by using PtRh1O-Pt thermocouple.

  2. Research on Stealthy Headphone Detector Based on Geomagnetic Sensor

    Directory of Open Access Journals (Sweden)

    Liu Ya

    2016-01-01

    Full Text Available A kind of stealth headphone detector based on geomagnetic sensor has been developed to deal with the stealth headphones which are small, extremely stealthy and hard to detect. The U.S. PNI geomagnetic sensor is chosen to obtain magnetic field considering the strong magnetic performance of stealth headphones. The earth’s magnetic field at the geomagnetic sensor is eliminated by difference between two geomagnetic sensors, and then weak variations of magnetic field is detected. STM8S103K2 is chosen as the central controlling chip, which is connected to LED, buzzer and LCD 1602. As shown by the experimental results, the probe is not liable to damage by the magnetic field and the developed device has high sensitivity, low False Positive Rate (FAR and satisfactory reliability.

  3. A Microring Resonator Based Negative Permeability Metamaterial Sensor

    Directory of Open Access Journals (Sweden)

    Yao-Zhong Lan

    2011-08-01

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

  4. Whitelists Based Multiple Filtering Techniques in SCADA Sensor Networks

    Directory of Open Access Journals (Sweden)

    DongHo Kang

    2014-01-01

    Full Text Available Internet of Things (IoT consists of several tiny devices connected together to form a collaborative computing environment. Recently IoT technologies begin to merge with supervisory control and data acquisition (SCADA sensor networks to more efficiently gather and analyze real-time data from sensors in industrial environments. But SCADA sensor networks are becoming more and more vulnerable to cyber-attacks due to increased connectivity. To safely adopt IoT technologies in the SCADA environments, it is important to improve the security of SCADA sensor networks. In this paper we propose a multiple filtering technique based on whitelists to detect illegitimate packets. Our proposed system detects the traffic of network and application protocol attacks with a set of whitelists collected from normal traffic.

  5. Sequestering ability to Cu2+of a new bodipy-based dye and its behavior as in vitro fluorescent sensor.

    Science.gov (United States)

    Papalia, Teresa; Barattucci, Anna; Barreca, Davide; Bellocco, Ersilia; Bonaccorsi, Paola; Minuti, Lucio; Nicolò, Marco Sebastiano; Temperini, Andrea; Foti, Claudia

    2017-02-01

    A Bodipy (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) derivative has been conceived and synthesized starting from l-aspartic acid, as a selective turn-off sensor of Cu 2+ ions. Its acid-base properties were determined to study the formation of metal/sensor complex species by titration of solutions each containing a different metal ion, such as Cu 2+ , Ca 2+ , Zn 2+ , Pb 2+ and Hg 2+ and different metal/sensor ratios. The speciation models allowed us to simulate the distribution of the metal/sensor complex species at the normal concentrations of the corresponding metals present in biological fluids. The distribution diagrams, obtained by varying the concentration of sensor 1, clearly indicate that sensor 1 responds selectively to Cu 2+ at micromolar concentrations, even in the presence of other more abundant metal cations Ca 2+ . Finally, we analyzed the cellular uptake of sensor 1 on human erythrocytes and its ability to chelate Cu 2+ in the cellular environment. Results indicate that it crosses the plasmatic membrane and colors the cells of a bright fluorescent red. Exposing the fluorescent cells to Cu 2+ results in a complete cellular photobleaching of the red fluorescence, indicating that sensor 1 is able to detect metal changes in the cytosolic environment. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. An Immunity-Based Anomaly Detection System with Sensor Agents

    Directory of Open Access Journals (Sweden)

    Yoshiteru Ishida

    2009-11-01

    Full Text Available This paper proposes an immunity-based anomaly detection system with sensor agents based on the specificity and diversity of the immune system. Each agent is specialized to react to the behavior of a specific user. Multiple diverse agents decide whether the behavior is normal or abnormal. Conventional systems have used only a single sensor to detect anomalies, while the immunity-based system makes use of multiple sensors, which leads to improvements in detection accuracy. In addition, we propose an evaluation framework for the anomaly detection system, which is capable of evaluating the differences in detection accuracy between internal and external anomalies. This paper focuses on anomaly detection in user’s command sequences on UNIX-like systems. In experiments, the immunity-based system outperformed some of the best conventional systems.

  7. An immunity-based anomaly detection system with sensor agents.

    Science.gov (United States)

    Okamoto, Takeshi; Ishida, Yoshiteru

    2009-01-01

    This paper proposes an immunity-based anomaly detection system with sensor agents based on the specificity and diversity of the immune system. Each agent is specialized to react to the behavior of a specific user. Multiple diverse agents decide whether the behavior is normal or abnormal. Conventional systems have used only a single sensor to detect anomalies, while the immunity-based system makes use of multiple sensors, which leads to improvements in detection accuracy. In addition, we propose an evaluation framework for the anomaly detection system, which is capable of evaluating the differences in detection accuracy between internal and external anomalies. This paper focuses on anomaly detection in user's command sequences on UNIX-like systems. In experiments, the immunity-based system outperformed some of the best conventional systems.

  8. A Polymer Optical Fiber Temperature Sensor Based on Material Features.

    Science.gov (United States)

    Leal-Junior, Arnaldo; Frizera-Netoc, Anselmo; Marques, Carlos; Pontes, Maria José

    2018-01-19

    This paper presents a polymer optical fiber (POF)-based temperature sensor. The operation principle of the sensor is the variation in the POF mechanical properties with the temperature variation. Such mechanical property variation leads to a variation in the POF output power when a constant stress is applied to the fiber due to the stress-optical effect. The fiber mechanical properties are characterized through a dynamic mechanical analysis, and the output power variation with different temperatures is measured. The stress is applied to the fiber by means of a 180° curvature, and supports are positioned on the fiber to inhibit the variation in its curvature with the temperature variation. Results show that the sensor proposed has a sensitivity of 1.04 × 10 -3 °C -1 , a linearity of 0.994, and a root mean squared error of 1.48 °C, which indicates a relative error of below 2%, which is lower than the ones obtained for intensity-variation-based temperature sensors. Furthermore, the sensor is able to operate at temperatures up to 110 °C, which is higher than the ones obtained for similar POF sensors in the literature.

  9. A smart sensor-based vision system: implementation and evaluation

    International Nuclear Information System (INIS)

    Elouardi, A; Bouaziz, S; Dupret, A; Lacassagne, L; Klein, J O; Reynaud, R

    2006-01-01

    One of the methods of solving the computational complexity of image-processing is to perform some low-level computations on the sensor focal plane. This paper presents a vision system based on a smart sensor. PARIS1 (Programmable Analog Retina-like Image Sensor1) is the first prototype used to evaluate the architecture of an on-chip vision system based on such a sensor coupled with a microcontroller. The smart sensor integrates a set of analog and digital computing units. This architecture paves the way for a more compact vision system and increases the performances reducing the data flow exchanges with a microprocessor in control. A system has been implemented as a proof-of-concept and has enabled us to evaluate the performance requirements for a possible integration of a microcontroller on the same chip. The used approach is compared with two architectures implementing CMOS active pixel sensors (APS) and interfaced to the same microcontroller. The comparison is related to image processing computation time, processing reliability, programmability, precision, bandwidth and subsequent stages of computations

  10. Disposable copper-based electrochemical sensor for anodic stripping voltammetry.

    Science.gov (United States)

    Pei, Xing; Kang, Wenjing; Yue, Wei; Bange, Adam; Heineman, William R; Papautsky, Ian

    2014-05-20

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

  11. Fabrication of strain gauge based sensors for tactile skins

    Science.gov (United States)

    Baptist, Joshua R.; Zhang, Ruoshi; Wei, Danming; Saadatzi, Mohammad Nasser; Popa, Dan O.

    2017-05-01

    Fabricating cost effective, reliable and functional sensors for electronic skins has been a challenging undertaking for the last several decades. Application of such skins include haptic interfaces, robotic manipulation, and physical human-robot interaction. Much of our recent work has focused on producing compliant sensors that can be easily formed around objects to sense normal, tension, or shear forces. Our past designs have involved the use of flexible sensors and interconnects fabricated on Kapton substrates, and piezoresistive inks that are 3D printed using Electro Hydro Dynamic (EHD) jetting onto interdigitated electrode (IDE) structures. However, EHD print heads require a specialized nozzle and the application of a high-voltage electric field; for which, tuning process parameters can be difficult based on the choice of inks and substrates. Therefore, in this paper we explore sensor fabrication techniques using a novel wet lift-off photolithographic technique for patterning the base polymer piezoresistive material, specifically Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) or PEDOT:PSS. Fabricated sensors are electrically and thermally characterized, and temperaturecompensated designs are proposed and validated. Packaging techniques for sensors in polymer encapsulants are proposed and demonstrated to produce a tactile interface device for a robot.

  12. BAW sensor readout circuit based on Pierce oscillator architecture

    Science.gov (United States)

    Gao, Yang; Yin, Xi-Yang; Han, Bin; Wang, Yu-Hang

    2017-10-01

    Bulk Acoustic Wave Resonators (BAWRs) have been well developed both as filters and as high sensitivity sensors in recent years. In contrast to traditional megahertz quartz resonators, BAWRs offer significant increases in resonant frequency, typically operating in gigahertz regimes. This translates into a potential sensitivity increase of more than three orders of magnitude over traditional QCM (Quartz Crystal Microbalance) devices. Given the micrometer-scale size of BAW sensor-head, read-out circuitry can monolithic integrated with this GHz transducer is urgently needed to produce small, robust, and inexpensive sensor systems. A BAW sensor read-out circuit prototype based on Pierce oscillator architecture is fulfilled in this paper. Based on the differential measurement scheme, two uniform BAWRs are used to constitute two BAW oscillators as a reference and a measurement branch respectively. The resonant frequency shift caused by the measurand is obtained by mixing and filtering the two oscillator signals. Then, the intermediate signal is amplified, shaped and converted to a digital one. And a FPGA is used for frequency detection. Taking 2 GHz BAW mass sensor as a case study, deign procedure are given in details. Simulation and experimental results reveal a 0-99 MHz frequency shift measurement range. Main factors affecting phase noise of the BAW oscillator (i.e. mainly frequency stability of the BAW sensor readout circuit) are also discussed for further optimizations.

  13. APTAMER-BASED SERRS SENSOR FOR THROMBIN DETECTION

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-07-02

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

  14. Vibronics and plasmonics based graphene sensors.

    Science.gov (United States)

    Rangel, Norma L; Seminario, Jorge M

    2010-03-28

    A high sensitivity and selectivity sensor is proposed using graphene ribbons which are able to read molecular vibrations and molecular electrostatic potentials, acting as an amplifier and as a transducer converting molecular signals into current-voltage quantities of standard electronics. Two sensing mechanisms are used to demonstrate the concept using ab initio density functional methods. By using the terahertz region of the spectrum, we can characterize modes when single molecules are adsorbed on the ribbon surface. Characteristic modes can be obtained and used as fingerprints, which can be transduced into current by applying a voltage along the ribbons. On the other hand, the fully delocalized frontier molecular orbitals of graphene ribbons, commonly denominated plasmons in larger solid state structures, are extremely sensitive to any moiety approach; once plasmons are in contact with an "agent" (actually its molecular potential), the transport through the ribbons acting as electrodes catching the signals is strongly affected.

  15. Sensor fusion for structural tilt estimation using an acceleration-based tilt sensor and a gyroscope

    Science.gov (United States)

    Liu, Cheng; Park, Jong-Woong; Spencer, B. F., Jr.; Moon, Do-Soo; Fan, Jiansheng

    2017-10-01

    A tilt sensor can provide useful information regarding the health of structural systems. Most existing tilt sensors are gravity/acceleration based and can provide accurate measurements of static responses. However, for dynamic tilt, acceleration can dramatically affect the measured responses due to crosstalk. Thus, dynamic tilt measurement is still a challenging problem. One option is to integrate the output of a gyroscope sensor, which measures the angular velocity, to obtain the tilt; however, problems arise because the low-frequency sensitivity of the gyroscope is poor. This paper proposes a new approach to dynamic tilt measurements, fusing together information from a MEMS-based gyroscope and an acceleration-based tilt sensor. The gyroscope provides good estimates of the tilt at higher frequencies, whereas the acceleration measurements are used to estimate the tilt at lower frequencies. The Tikhonov regularization approach is employed to fuse these measurements together and overcome the ill-posed nature of the problem. The solution is carried out in the frequency domain and then implemented in the time domain using FIR filters to ensure stability. The proposed method is validated numerically and experimentally to show that it performs well in estimating both the pseudo-static and dynamic tilt measurements.

  16. Vision communications based on LED array and imaging sensor

    Science.gov (United States)

    Yoo, Jong-Ho; Jung, Sung-Yoon

    2012-11-01

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

  17. Autonomous star tracker based on active pixel sensors (APS)

    Science.gov (United States)

    Schmidt, U.

    2017-11-01

    Star trackers are opto-electronic sensors used onboard of satellites for the autonomous inertial attitude determination. During the last years, star trackers became more and more important in the field of the attitude and orbit control system (AOCS) sensors. High performance star trackers are based up today on charge coupled device (CCD) optical camera heads. The Jena-Optronik GmbH is active in the field of opto-electronic sensors like star trackers since the early 80-ties. Today, with the product family ASTRO5, ASTRO10 and ASTRO15, all marked segments like earth observation, scientific applications and geo-telecom are supplied to European and Overseas customers. A new generation of star trackers can be designed based on the APS detector technical features. The measurement performance of the current CCD based star trackers can be maintained, the star tracker functionality, reliability and robustness can be increased while the unit costs are saved.

  18. Aptamer based electrochemical sensors for emerging environmental pollutants

    Directory of Open Access Journals (Sweden)

    Akhtar eHAYAT

    2014-06-01

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

  19. A bionic camera-based polarization navigation sensor.

    Science.gov (United States)

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

    2014-07-21

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

  20. Ionic Liquid based polymer electrolytes for electrochemical sensors

    Directory of Open Access Journals (Sweden)

    Jakub Altšmíd

    2015-09-01

    Full Text Available Amperometric NO2 printed sensor with a new type of solid polymer electrolyte and a carbon working electrode has been developed. The electrolytes based on 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonylimide [EMIM][N(Tf2], 1-butyl-3-methylimidazolium trifluoromethanesulfonate [BMIM][CF3SO3] and 1-ethyl-3-methylimidazolium tetrafluoroborate [EMIM][BF4] ionic liquids were immobilized in poly(vinylidene fluoride matrix [PVDF]. The analyte, gaseous nitrogen dioxide, was detected by reduction at -500 mV vs. platinum pseudoreference electrode. The sensors showed a linear behavior in the whole tested range, i.e., 0 - 5 ppm and their sensitivities were in order of 0.3 x∙10-6 A/ppm. The sensor sensitivity was influenced by the electric conductivity of printing formulation; the higher the conductivity, the higher the sensor sensitivity. The rise/recovery times were in order of tens of seconds. The use of  screen printing technology and platinum pseudoreference electrode simplify the sensor fabrication and it does not have any negative effect on the sensor stability.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7371

  1. Resonant Magnetic Field Sensors Based On MEMS Technology

    Directory of Open Access Journals (Sweden)

    Elías Manjarrez

    2009-09-01

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

  2. Resonant Magnetic Field Sensors Based On MEMS Technology

    Science.gov (United States)

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

    2009-01-01

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

  3. Resonant Magnetic Field Sensors Based On MEMS Technology.

    Science.gov (United States)

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

    2009-01-01

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

  4. The Single Transmembrane Segment of Minimal Sensor DesK Senses Temperature via a Membrane-Thickness Caliper.

    Science.gov (United States)

    Inda, Maria E; Oliveira, Rafael G; de Mendoza, Diego; Cybulski, Larisa E

    2016-11-01

    Thermosensors detect temperature changes and trigger cellular responses crucial for survival at different temperatures. The thermosensor DesK is a transmembrane (TM) histidine kinase which detects a decrease in temperature through its TM segments (TMS). Here, we address a key issue: how a physical stimulus such as temperature can be converted into a cellular response. We show that the thickness of Bacillus lipid membranes varies with temperature and that such variations can be detected by DesK with great precision. On the basis of genetic studies and measurements of in vitro activity of a DesK construct with a single TMS (minimal sensor DesK [MS-DesK]), reconstituted in liposomes, we propose an interplay mechanism directed by a conserved dyad, phenylalanine 8-lysine 10. This dyad is critical to anchor the only transmembrane segment of the MS-DesK construct to the extracellular water-lipid interphase and is required for the transmembrane segment of MS-DesK to function as a caliper for precise measurement of membrane thickness. The data suggest that positively charged lysine 10, which is located in the hydrophobic core of the membrane but is close to the water-lipid interface, pulls the transmembrane region toward the water phase to localize its charge at the interface. Nevertheless, the hydrophobic residue phenylalanine 8, located at the N-terminal extreme of the TMS, has a strong tendency to remain in the lipid phase, impairing access of lysine 10 to the water phase. The outcome of this interplay is a fine-tuned sensitivity to membrane thickness that elicits conformational changes that favor different signaling states of the protein. The ability to sense and respond to extracellular signals is essential for cell survival. One example is the cellular response to temperature variation. How do cells "sense" temperature changes? It has been proposed that the bacterial thermosensor DesK acts as a molecular caliper measuring membrane thickness variations that would occur

  5. Towards Scalable Strain Gauge-Based Joint Torque Sensors

    Science.gov (United States)

    D’Imperio, Mariapaola; Cannella, Ferdinando; Caldwell, Darwin G.; Cuschieri, Alfred

    2017-01-01

    During recent decades, strain gauge-based joint torque sensors have been commonly used to provide high-fidelity torque measurements in robotics. Although measurement of joint torque/force is often required in engineering research and development, the gluing and wiring of strain gauges used as torque sensors pose difficulties during integration within the restricted space available in small joints. The problem is compounded by the need for a scalable geometric design to measure joint torque. In this communication, we describe a novel design of a strain gauge-based mono-axial torque sensor referred to as square-cut torque sensor (SCTS), the significant features of which are high degree of linearity, symmetry, and high scalability in terms of both size and measuring range. Most importantly, SCTS provides easy access for gluing and wiring of the strain gauges on sensor surface despite the limited available space. We demonstrated that the SCTS was better in terms of symmetry (clockwise and counterclockwise rotation) and more linear. These capabilities have been shown through finite element modeling (ANSYS) confirmed by observed data obtained by load testing experiments. The high performance of SCTS was confirmed by studies involving changes in size, material and/or wings width and thickness. Finally, we demonstrated that the SCTS can be successfully implementation inside the hip joints of miniaturized hydraulically actuated quadruped robot-MiniHyQ. This communication is based on work presented at the 18th International Conference on Climbing and Walking Robots (CLAWAR). PMID:28820446

  6. Electrochemical DNA Hybridization Sensors Based on Conducting Polymers

    Science.gov (United States)

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

    2015-01-01

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

  7. Progress in triboluminescence-based smart optical sensor system

    International Nuclear Information System (INIS)

    Olawale, David O.; Dickens, Tarik; Sullivan, William G.; Okoli, Okenwa I.; Sobanjo, John O.; Wang, Ben

    2011-01-01

    Extensive research work has been done in recent times to apply the triboluminescence (TL) phenomenon for damage detection in engineering structures. Of particular note are the various attempts to apply it in the detection of impact damages in composites and aerospace structures. This is because TL-based sensor systems have a great potential for wireless, in-situ and distributed (WID) structural health monitoring when fully developed. This review article highlights development and the current state-of-the-art in the application of TL-based sensor systems. The underlying mechanisms believed to be responsible for triboluminescence, particularly in zinc sulfide manganese, a highly triboluminescent material, are discussed. The challenges militating against the full exploitation and field application of TL sensor systems are also identified. Finally, viable solutions and approaches to address these challenges are enumerated. - Highlights: → The underlying mechanisms believed to be responsible for triboluminescence. → State-of-the-art in the development and application of TL-based sensor systems. → The challenges militating against the full exploitation and field application of TL sensor systems are identified. → Viable solutions and approaches to address these challenges are enumerated.

  8. Ligand exchange based paraoxon imprınted QCM sensor.

    Science.gov (United States)

    Özkütük, Ebru Birlik; Diltemiz, Sibel Emir; Özalp, Elif; Say, Rıdvan; Ersöz, Arzu

    2013-03-01

    In the present work, a paraoxon imprinted QCM sensor has been developed for the determination of paraoxon based on the modification of paraoxon imprinted film onto a quartz crystal combining the advantages of high selectivity of the piezoelectric microgravimetry using MIP film technique and high sensitivity of QCM detection. The paraoxon selective memories have formed on QCM electrode surface by using a new metal-chelate interaction based on pre-organized monomer and the paraoxon recognition activity of these molecular memories was investigated. Molecular imprinted polymer (MIP) film for the detection of paraoxon was developed and the analytical performance of paraoxon imprinted sensor was studied. The molecular imprinted polymer were characterized by FTIR measurements. Paraoxon imprinted sensor was characterized with AFM and ellipsometer. The study also includes the measurement of binding interaction of paraoxon imprinted quartz crystal microbalance (QCM) sensor, selectivity experiments and analytical performance of QCM electrode. The detection limit and the affinity constant (K(affinity)) were found to be 0.06 μM and 2.25 × 10(4) M(-1) for paraoxon [MAAP-Cu(II)-paraoxon] based thin film, respectively. Also, it has been observed that the selectivity of the prepared paraoxon imprinted sensor is high compared to a similar chemical structure which is parathion. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Electrochemical DNA Hybridization Sensors Based on Conducting Polymers

    Directory of Open Access Journals (Sweden)

    Md. Mahbubur Rahman

    2015-02-01

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

  10. Fast humidity sensors based on CeO2 nanowires

    International Nuclear Information System (INIS)

    Fu, X Q; Wang, C; Yu, H C; Wang, Y G; Wang, T H

    2007-01-01

    Fast humidity sensors are reported that are based on CeO 2 nanowires synthesized by a hydrothermal method. Both the response and recovery time are about 3 s, and are independent of the humidity. The sensitivity increases gradually as the humidity increases, and is up to 85 at 97% RH. The resistance decreases exponentially with increasing humidity, implying ion-type conductivity as the humidity sensing mechanism. A model based on the morphology and surface energy of the nanowires is given to explain these results further. Our experimental results indicate a pathway to improving the performance of humidity sensors

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

    Science.gov (United States)

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

    2017-10-11

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

  12. Validation of Underwater Sensor Package Using Feature Based SLAM

    Directory of Open Access Journals (Sweden)

    Christopher Cain

    2016-03-01

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

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

    Science.gov (United States)

    Cain, Christopher; Leonessa, Alexander

    2016-03-17

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

  14. Validation of Underwater Sensor Package Using Feature Based SLAM

    Science.gov (United States)

    Cain, Christopher; Leonessa, Alexander

    2016-01-01

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

  15. Recent progress in carbon nanotube-based gas sensors

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  16. Algorithm for Wireless Sensor Networks Based on Grid Management

    Directory of Open Access Journals (Sweden)

    Geng Zhang

    2014-05-01

    Full Text Available This paper analyzes the key issues for wireless sensor network trust model and describes a method to build a wireless sensor network, such as the definition of trust for wireless sensor networks, computing and credibility of trust model application. And for the problem that nodes are vulnerable to attack, this paper proposed a grid-based trust algorithm by deep exploration trust model within the framework of credit management. Algorithm for node reliability screening and rotation schedule to cover parallel manner based on the implementation of the nodes within the area covered by trust. And analyze the results of the size of trust threshold has great influence on the safety and quality of coverage throughout the coverage area. The simulation tests the validity and correctness of the algorithm.

  17. Nanomaterials-based electrochemical sensors for nitric oxide

    International Nuclear Information System (INIS)

    Dang, Xueping; Hu, Hui; Wang, Shengfu; Hu, Shengshui

    2015-01-01

    Electrochemical sensing has been demonstrated to represent an efficient way to quantify nitric oxide (NO) in challenging physiological environments. A sensing interface based on nanomaterials opens up new opportunities and broader prospects for electrochemical NO sensors. This review (with 141 refs.) gives a general view of recent advances in the development of electrochemical sensors based on nanomaterials. It is subdivided into sections on (i) carbon derived nanomaterials (such as carbon nanotubes, graphenes, fullerenes), (ii) metal nanoparticles (including gold, platinum and other metallic nanoparticles); (iii) semiconductor metal oxide nanomaterials (including the oxides of titanium, aluminum, iron, and ruthenium); and finally (iv) nanocomposites (such as those formed from carbon nanomaterials with nanoparticles of gold, platinum, NiO or TiO 2 ). The various strategies are discussed, and the advances of using nanomaterials and the trends in NO sensor technology are outlooked in the final section. (author)

  18. An Intelligent Logistics Tracking System Based on Wireless Sensor Network

    Directory of Open Access Journals (Sweden)

    Xing Jijun

    2018-01-01

    Full Text Available In view of the shortcomings in information collection and tracking management in existing logistics, the key technologies of wireless sensor network and the basic concepts and methods of Information Technology Infrastructure Library(ITIL is studied. The basic structure and main functions of the logistics tracking system based on wireless sensor network is put forward. It can effectively solve the detection, location, recognition and automatic processing of fault events and other issues of goods in the process of logistics tracking management. In addition, combined with the GIS software, the logistics tracking and monitoring system based on the wireless sensor network is realized by using Java language coding. The results show that this system can realize the tracking, visualization and automatic management of the information in the process of goods transportation. Therefore, the proposed method significantly improves the accuracy, rapidity and intuition of the logistics information management.

  19. Vision Based Navigation Sensors for Spacecraft Rendezvous and Docking

    DEFF Research Database (Denmark)

    Benn, Mathias

    of this constellation, providing both position and pose information for the Target vehicle. This dissertation will describe the study, implementation and verification methods that has led to the realization of this optical Vision Based Sensor (VBS), which is used on the PRISMA mission. On June 15th 2010 the PRISMA....... Denmark has, with DTUs design of the Swarm mission, ESAs next Earth Observation Programme magnetic mapping mission, and DTUs participation in GRACE, ELISA and Alsat2, a leading role in designing and verifying sensor systems for this new class of spacecraft. The Swedish led PRISMA mission...... is a technological demonstration mission, where all aspects of space rendezvous and docking to both a cooperative and a non-cooperative target is researched, with the use of novel methods, instruments and technologies. Amongst other equipment, DTU has delivered a vision based sensor package to the Main spacecraft...

  20. Construction of Tb3+ PVC-MembraneElectrode Based on N,N’-Bis(pyrrolylmethylene-2-aminobenzylamine

    Directory of Open Access Journals (Sweden)

    Hassan Ali Zamani

    2011-01-01

    Full Text Available In this work, we report as new Tb3+-PVC membrane sensor based on N,N’-bis(pyrrolylmethylene- 2-aminobenzylamine (PMA as a suitable ion carrier. Poly vinylchloride (PVC-based membrane composed of PMA with oleic acid (OA as anionic additives and acetophenone (AP as plasticizing solvent mediators. The Tb3+ sensor exhibits a Nernstian slope of 19.7±0.4 mV per decade over the concentration range of 1.0×10-5 to 1.0×10-2 M and a detection limit of 4.6×10-6 M of Tb3+ ions. The potentiometric response of the sensor is independent of the solution pH in the range of 2.9–8.1. It has a very short response time, in the whole concentration range (∼5 s. The recommended sensor revealed comparatively good selectivity with respect to most alkali, alkaline earth, some transition and heavy metal ions. It was successfully employed as an indicator electrode in the potentiometric titration of Tb(III ions with EDTA. The electrode was also employed for the determination of the fluoride ion in two mouth wash preparations and the determination of Tb3+ ions concentration in mixtures of three different ions.

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

    Directory of Open Access Journals (Sweden)

    Gabriele Ferri

    2010-08-01

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

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

    Science.gov (United States)

    Li, Jing; Lu, Yijiang

    2009-01-01

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

  3. The Modification of Fuel Cell-Based Breath Alcohol Sensor Materials to Improve Water Retention of Sensing Performance

    Science.gov (United States)

    Allan, Jesse

    Fuel cell based breath alcohol sensors (BrASs) are one of the most important tools used by law enforcement today. The ability to screen potentially intoxicated subjects with the ease, speed, and flexibility the BrAS can provide is unmatched by any other device of its kind. While these devices are used globally, they all suffer from a common deficiency: reliance on water. The ability of the fuel cell sensor to manage water content is one of the greatest fundamental challenges facing this technology today. In order to evaluate the fuel cell sensor device, a methodology was required that would allow in-house sensor testing to be coupled with a diagnostic testing method to not only test materials sensing performance, but also determine why a sensor behaved how it did. To do this, a next-generation fuel cell was designed specifically for sensor testing along with a test station that allowed for rapid response and sensor characteristics of a given material. The fuel cell was designed to allow in-situ testing of a membrane electrode assembly (MEA) of interest using cyclic voltammetry and electrochemical impedance spectroscopy. The in-house design was validated against a commercial cell to provide feedback on how materials in the in-house cell would behave in a commercial designed unit. The results showed that our cell with a commercial MEA behaved identically to a commercial cell with the same MEA. Following validation of our cell, common membrane materials were investigated to identify their suitability in a senor role. The materials chosen were designed for power generating devices, so they provided a benchmark to identify which properties would be important for sensor operation. It was found that while the Nafion membrane and sulfonated poly (ether ether ketone) did show performance increases over the commercial MEA, the thin characteristics of these membranes limited performance in drier conditions. From these results, it was determined that thicker membrane materials

  4. Sensors and packages based on LTCC and thick-film technology for ...

    Indian Academy of Sciences (India)

    process, which simultaneously accomplishes three functions: (i) hermetic separation of the sensor cavity and resistors from ... process is compatible with low-cost batch production. 2.2 Jet engine AMB sensor .... which are well-suited for creating a well-controlled resistance to gas flow, and large and flat membranes allowing ...

  5. Enhanced response of microbial fuel cell using sulfonated poly ether ether ketone membrane as a biochemical oxygen demand sensor

    International Nuclear Information System (INIS)

    Ayyaru, Sivasankaran; Dharmalingam, Sangeetha

    2014-01-01

    Graphical abstract: - Highlights: • Sulfonated poly ether ether ketone (SPEEK) membrane in SCMFC used to determine the BOD. • The biosensor produces a good linear relationship with the BOD concentration up to 650 ppm. • This sensing range was 62.5% higher than that of Nafion ® . • SPEEK exhibited one order lesser oxygen permeability than Nafion ® . • Nafion ® shows high anodic internal resistance (67 Ω) than the SPEEK (39 Ω). - Abstract: The present study is focused on the development of single chamber microbial fuel cell (SCMFC) using sulfonated poly ether ether ketone (SPEEK) membrane to determine the biochemical oxygen demand (BOD) matter present in artificial wastewater (AW). The biosensor produces a good linear relationship with the BOD concentration up to 650 ppm when using artificial wastewater. This sensing range was 62.5% higher than that of Nafion ® . The most serious problem in using MFC as a BOD sensor is the oxygen diffusion into the anode compartment, which consumes electrons in the anode compartment, thereby reducing the coulomb yield and reducing the electrical signal from the MFC. SPEEK exhibited one order lesser oxygen permeability than Nafion ® , resulting in low internal resistance and substrate loss, thus improving the sensing range of BOD. The system was further improved by making a double membrane electrode assembly (MEA) with an increased electrode surface area which provide high surface area for electrically active bacteria

  6. EGFET pH Sensor Performance Dependence on Sputtered TiO2 Sensing Membrane Deposition Temperature

    Directory of Open Access Journals (Sweden)

    Khairul Aimi Yusof

    2016-01-01

    Full Text Available Titanium dioxide (TiO2 thin films were sputtered by radio frequency (RF magnetron sputtering method and have been employed as the sensing membrane of an extended gate field effect transistor (EGFET for pH sensing detection application. The TiO2 thin films were deposited onto indium tin oxide (ITO coated glass substrates at room temperature and 200°C, respectively. The effect of deposition temperature on thin film properties and pH detection application was analyzed. The TiO2 samples used as the sensing membrane for EGFET pH-sensor and the current-voltage (I-V, hysteresis, and drift characteristics were examined. The sensitivity of TiO2 EGFET sensing membrane was obtained from the transfer characteristic (I-V curves for different substrate heating temperatures. TiO2 thin film sputtered at room temperature achieved higher sensitivity of 59.89 mV/pH compared to the one deposited at 200°C indicating lower sensitivity of 37.60 mV/pH. Moreover the hysteresis and the drift of TiO2 thin film deposited at room temperature showed lower values compared to the one at 200°C. We have also tested the effect of operating temperature on the performance of the EGFET pH-sensing and found that the temperature effect was very minimal.

  7. Enhanced response of microbial fuel cell using sulfonated poly ether ether ketone membrane as a biochemical oxygen demand sensor

    Energy Technology Data Exchange (ETDEWEB)

    Ayyaru, Sivasankaran; Dharmalingam, Sangeetha, E-mail: sangeetha@annauniv.edu

    2014-03-01

    Graphical abstract: - Highlights: • Sulfonated poly ether ether ketone (SPEEK) membrane in SCMFC used to determine the BOD. • The biosensor produces a good linear relationship with the BOD concentration up to 650 ppm. • This sensing range was 62.5% higher than that of Nafion{sup ®}. • SPEEK exhibited one order lesser oxygen permeability than Nafion{sup ®}. • Nafion{sup ®} shows high anodic internal resistance (67 Ω) than the SPEEK (39 Ω). - Abstract: The present study is focused on the development of single chamber microbial fuel cell (SCMFC) using sulfonated poly ether ether ketone (SPEEK) membrane to determine the biochemical oxygen demand (BOD) matter present in artificial wastewater (AW). The biosensor produces a good linear relationship with the BOD concentration up to 650 ppm when using artificial wastewater. This sensing range was 62.5% higher than that of Nafion{sup ®}. The most serious problem in using MFC as a BOD sensor is the oxygen diffusion into the anode compartment, which consumes electrons in the anode compartment, thereby reducing the coulomb yield and reducing the electrical signal from the MFC. SPEEK exhibited one order lesser oxygen permeability than Nafion{sup ®}, resulting in low internal resistance and substrate loss, thus improving the sensing range of BOD. The system was further improved by making a double membrane electrode assembly (MEA) with an increased electrode surface area which provide high surface area for electrically active bacteria.

  8. High performance liquid-level sensor based on mPOFBG for aircraft applications

    DEFF Research Database (Denmark)

    Marques, C. A. F.; Pospori, A.; Saez-Rodriguez, D.

    2015-01-01

    A high performance liquid-level sensor based on microstructured polymer optical fiber Bragg grating (mPOFBG) array sensors is reported in detail. The sensor sensitivity is found to be 98pm/cm of liquid, enhanced by more than a factor of 9 compared to a reported silica fiber-based sensor....

  9. Sensor of hydrostatic pressure based on gallium antimonide microcrystals

    Directory of Open Access Journals (Sweden)

    Druzhinin A. A.

    2015-08-01

    Full Text Available Currently, silicon and germanium, the most common materials in the production of discrete semiconductor devices and integrated circuits, do not always meet all the requirements to the sensing elements of mechanical quantities sensors. Therefore, it is logical to research the properties of other semiconductor materials that could be used as sensing elements in such sensors. A3B5 semiconductor compounds seem promising for such purpose. Effect of hydrostatic pressure up to 5000 bar on the resistance of n-type antimonide gallium whiskers doped by Se or Te was studied. Coefficient of hydrostatic pressure for this crystals was determined, it equals Kh = (16,5—20,0•10–5 bar–1 at 20°N. Temperature dependence of resistance and coefficient Kh for this crystals in the temperature range ±60°N was studied. Design of the developed hydrostatic pressure sensor based on GaSb whiskers and its characteristics are presented. The possibility to decrease the temperature dependence of sensitive element resistance by mounting GaSb whiskers on the substrates fabricated from materials with different temperature coefficient of expansion was examined. It was shown that mounting of GaSb crystals on Cu substrate gives the optimal result, in this case the temperature coefficient decrease to 0,05%•°N–1, that leads to decrease of output temperature dependence. The main advantages of developed pressure sensor are: the simplified design in comparison with pressure sensors with strain gauges mounted on spring elements; the high sensitivity to pressure that is constant in the wide pressure range; the improvement of sensors metrological characteristics owing to hysteresis absence. The possible application fields of developed sensors are measuring of high and extremely high pressure, chemical and oil industries, measuring of pressure in oil bore-holes, investigation of explosive processes.

  10. Study of photoconductor-based radiological image sensors

    International Nuclear Information System (INIS)

    Beaumont, Francois

    1989-01-01

    Because of the evolution of medical imaging techniques to digital Systems, it is necessary to replace radiological film which has many drawbacks, by a detector quite as efficient and quickly giving a digitizable signal. The purpose of this thesis is to find new X-ray digital imaging processes using photoconductor materials such as amorphous selenium. After reviewing the principle of direct radiology and functions to be served by the X-ray sensor (i.e. detection, memory, assignment, visualization), we explain specification. We especially show the constraints due to the object to be radiographed (condition of minimal exposure), and to the reading signal (electronic noise detection associated with a reading frequency). As a result of this study, a first photoconductor sensor could be designed. Its principle is based on photo-carrier trapping at dielectric-photoconductor structure interface. The reading System needs the scanning of a laser beam upon the sensor surface. The dielectric-photoconductor structure enabled us to estimate the possibilities offered by the sensor and to build a complete x-ray imaging System. The originality of thermo-dielectric sensor, that was next studied, is to allow a thermal assignment reading. The chosen System consists in varying the ferroelectric polymer capacity whose dielectric permittivity is weak at room temperature. The thermo-dielectric material was studied by thermal or Joule effect stimulation. During our experiments, trapping was found in a sensor made of amorphous selenium between two electrodes. This new effect was performed and enabled us to expose a first interpretation. Eventually, the comparison of these new sensor concepts with radiological film shows the advantage of the proposed solution. (author) [fr

  11. GA-Based Membrane Evolutionary Algorithm for Ensemble Clustering

    Directory of Open Access Journals (Sweden)

    Yanhua Wang

    2017-01-01

    Full Text Available Ensemble clustering can improve the generalization ability of a single clustering algorithm and generate a more robust clustering result by integrating multiple base clusterings, so it becomes the focus of current clustering research. Ensemble clustering aims at finding a consensus partition which agrees as much as possible with base clusterings. Genetic algorithm is a highly parallel, stochastic, and adaptive search algorithm developed from the natural selection and evolutionary mechanism of biology. In this paper, an improved genetic algorithm is designed by improving the coding of chromosome. A new membrane evolutionary algorithm is constructed by using genetic mechanisms as evolution rules and combines with the communication mechanism of cell-like P system. The proposed algorithm is used to optimize the base clusterings and find the optimal chromosome as the final ensemble clustering result. The global optimization ability of the genetic algorithm and the rapid convergence of the membrane system make membrane evolutionary algorithm perform better than several state-of-the-art techniques on six real-world UCI data sets.

  12. GA-Based Membrane Evolutionary Algorithm for Ensemble Clustering.

    Science.gov (United States)

    Wang, Yanhua; Liu, Xiyu; Xiang, Laisheng

    2017-01-01

    Ensemble clustering can improve the generalization ability of a single clustering algorithm and generate a more robust clustering result by integrating multiple base clusterings, so it becomes the focus of current clustering research. Ensemble clustering aims at finding a consensus partition which agrees as much as possible with base clusterings. Genetic algorithm is a highly parallel, stochastic, and adaptive search algorithm developed from the natural selection and evolutionary mechanism of biology. In this paper, an improved genetic algorithm is designed by improving the coding of chromosome. A new membrane evolutionary algorithm is constructed by using genetic mechanisms as evolution rules and combines with the communication mechanism of cell-like P system. The proposed algorithm is used to optimize the base clusterings and find the optimal chromosome as the final ensemble clustering result. The global optimization ability of the genetic algorithm and the rapid convergence of the membrane system make membrane evolutionary algorithm perform better than several state-of-the-art techniques on six real-world UCI data sets.

  13. Implanted electroenzymatic glucose sensors.

    Science.gov (United States)

    Clark, L C; Duggan, C A

    1982-01-01

    The advent of electrochemical sensors for intermittent sampling of blood gases and hydrogen ions in the clinic, intensive care, and surgical units has revolutionized diagnostic and critical care medical technics. The use of electrochemical sensors for continuous transcutaneous monitoring of blood gases is further enhancing the medical surveillance of patients. The more recent introduction of glucose and other electroenzymatic sensors has stimulated broad research in the development of metabolic monitoring. For the present research, the glucose sensor widely used for the rapid specific micro-analysis of whole blood and plasma is explored for possible use as an in vivo intravascular or tissue-implanted sensor. This sensor is based on the polarographic measurement of hydrogen peroxide generated by glucose oxidase (EC 1.1.3.4) held between two membranes. The first membrane allows the diffusion of glucose, ions, and many other small molecules, while the second membrane allows the diffusion of the glucose-generated hydrogen peroxide to the platinum surface, but excludes ascorbic acid, bilirubin, and uric acid. Such sensors respond rapidly and specifically when acutely implanted subcutaneously in cats and dogs. They function well as glucose-sensor-tipped venous catheters. One sensor was repeatedly used for in vitro polarograms, subcutaneous and blood glucose monitoring, over a period of ten months, with storage in the cold between uses, with the complete retention of its response characteristics.

  14. Polymer-based stress sensor with integrated readout

    DEFF Research Database (Denmark)

    Thaysen, Jacob; Yalcinkaya, Arda Deniz; Vettiger, P.

    2002-01-01

    softer than silicon and that a gold resistor is easily incorporated in SU-8, we have proven that a SU-8-based cantilever sensor is almost as sensitive to stress changes as the silicon piezoresistive cantilever. First, the surface stress sensing principle is discussed, from which it can be shown...

  15. An Astigmatic Detection System for Polymeric Cantilever-based Sensors

    DEFF Research Database (Denmark)

    Hwu, En-Te; Liao, Hsien-Shun; Bosco, Filippo

    2012-01-01

    We demonstrate the use of an astigmatic detection system (ADS) for resonance frequency identification of polymer microcantilever sensors. The ADS technology is based on a DVD optical head combined with an optical microscope (OM). The optical head has a signal bandwidth of 80 MHz, allowing thermal...

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

    Science.gov (United States)

    He, Jing

    2012-01-01

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

  17. Advanced flooding-based routing protocols for underwater sensor networks

    NARCIS (Netherlands)

    Isufi, E.; Dol, H.; Leus, G.J.T.

    2016-01-01

    Flooding-based protocols are a reliable solution to deliver packets in underwater sensor networks. However, these protocols potentially involve all the nodes in the forwarding process. Thus, the performance and energy efficiency are not optimal. In this work, we propose some advances of a

  18. Molecularly Imprinted Polymer-Carbon Nanotube based Cotinine sensor

    NARCIS (Netherlands)

    Abbas, Yawar; Bomer, Johan G.; Brusse-Keizer, M.G.J.; Movig, K; van der Valk, P.D.L.P.M.; Pieterse, Marcel E.; Segerink, Loes Irene; Olthuis, Wouter; van den Berg, Albert

    2016-01-01

    A cotinine sensor based on the dc resistance of a polymer composite films is presented. The composite film comprises a cotinine selective molecularly imprinted polymer and carbon nanotube particles. This polymer film is deposited over a gold interdigitated electrode array to measure its electrical

  19. Hydrogen sensor based on palladium-yttrium alloy nanosheet

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Boyi [Queensland Micro- and Nanotechnology Centre, Griffith University, Nathan, QLD 4111 (Australia); Zhu, Yong, E-mail: y.zhu@griffith.edu.au [Queensland Micro- and Nanotechnology Centre, Griffith University, Nathan, QLD 4111 (Australia); Chen, Youping; Song, Han; Huang, Pengcheng [School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074 (China); Dao, Dzung Viet [Queensland Micro- and Nanotechnology Centre, Griffith University, Nathan, QLD 4111 (Australia)

    2017-06-15

    This paper presents a hydrogen sensor based on palladium-yttrium (Pd-Y) alloy nanosheet. Zigzag-shaped Pd-Y nanosheet with a thickness of 19.3 nm was deposited on a quartz substrate by using an ultrahigh-vacuum magnetron sputtering system and shadow mask. The atomic ratio of palladium to yttrium in the nanosheet was 0.92/0.08. The fabrication process was simple and low-cost, and the sensor can be mass-produced. The experimental results show the sensor has a superior sensitivity, reversibility, and reproducibility. The resistive-based hydrogen detection mechanism in this research is much simpler and more compact compared to the optical-based detection method. - Highlights: • Pd-Y sensing element was fabricated using a magnetron sputtering system and shadow mask. • The Pd-Y compound consisted of 92% Pd and 8% Y. • The fabrication process was simple, low-cost, and mass-production compatible. • The sensor showed superior sensitivity, reversibility, and reproducibility to hydrogen gas. • The device is more compact than the optical-based counterpart.

  20. Estimating spacecraft attitude based on in-orbit sensor measurements

    DEFF Research Database (Denmark)

    Jakobsen, Britt; Lyn-Knudsen, Kevin; Mølgaard, Mathias

    2014-01-01

    filter (EKF) is used for quaternion-based attitude estimation. A Simulink simulation environment developed for AAUSAT3, containing a "truth model" of the satellite and the orbit environment, is used to test the performance The performance is tested using different sensor noise parameters obtained both...

  1. Development of optoelectronic-based pulsed current sensor to ...

    Indian Academy of Sciences (India)

    Anil S Nayak

    2017-08-03

    Aug 3, 2017 ... A current transformer (CT)-based sensor has been developed to detect poor discharge conditions in copper vapour ... operator to initiate safety measures. Current ... The threshold value depends on the current flowing through the bypass inductor, which is an indication of the discharge condition of the CVL.

  2. Photonic-based multi-wavelength sensor for object identification.

    Science.gov (United States)

    Venkataraayan, Kavitha; Askraba, Sreten; Alameh, Kamal E; Smith, Clifton L

    2010-02-15

    A Photonic-based multi-wavelength sensor capable of discriminating objects is proposed and demonstrated for intruder detection and identification. The sensor uses a laser combination module for input wavelength signal multiplexing and beam overlapping, a custom-made curved optical cavity for multi-beam spot generation through internal beam reflection and transmission and a high-speed imager for scattered reflectance spectral measurements. Experimental results show that five different wavelengths, namely 473 nm, 532 nm, 635 nm, 670 nm and 785 nm, are necessary for discriminating various intruding objects of interest through spectral reflectance and slope measurements. Objects selected for experiments were brick, cement sheet, cotton, leather and roof tile.

  3. Measuring intracellular redox conditions using GFP-based sensors

    DEFF Research Database (Denmark)

    Björnberg, Olof; Ostergaard, Henrik; Winther, Jakob R

    2006-01-01

    Recent years have seen the development of methods for analyzing the redox conditions in specific compartments in living cells. These methods are based on genetically encoded sensors comprising variants of Green Fluorescent Protein in which vicinal cysteine residues have been introduced at solvent......-exposed positions. Several mutant forms have been identified in which formation of a disulfide bond between these cysteine residues results in changes of their fluorescence properties. The redox sensors have been characterized biochemically and found to behave differently, both spectroscopically and in terms...

  4. Water Pollution Detection Based on Hypothesis Testing in Sensor Networks

    Directory of Open Access Journals (Sweden)

    Xu Luo

    2017-01-01

    Full Text Available Water pollution detection is of great importance in water conservation. In this paper, the water pollution detection problems of the network and of the node in sensor networks are discussed. The detection problems in both cases of the distribution of the monitoring noise being normal and nonnormal are considered. The pollution detection problems are analyzed based on hypothesis testing theory firstly; then, the specific detection algorithms are given. Finally, two implementation examples are given to illustrate how the proposed detection methods are used in the water pollution detection in sensor networks and prove the effectiveness of the proposed detection methods.

  5. Recent Trends on Electrochemical Sensors Based on Ordered Mesoporous Carbon

    Science.gov (United States)

    Walcarius, Alain

    2017-01-01

    The past decade has seen an increasing number of extensive studies devoted to the exploitation of ordered mesoporous carbon (OMC) materials in electrochemistry, notably in the fields of energy and sensing. The present review summarizes the recent achievements made in field of electroanalysis using electrodes modified with such nanomaterials. On the basis of comprehensive tables, the interest in OMC for designing electrochemical sensors is illustrated through the various applications developed to date. They include voltammetric detection after preconcentration, electrocatalysis (intrinsically due to OMC or based on suitable catalysts deposited onto OMC), electrochemical biosensors, as well as electrochemiluminescence and potentiometric sensors. PMID:28800106

  6. Wireless Sensor Networks Data Processing Summary Based on Compressive Sensing

    Directory of Open Access Journals (Sweden)

    Caiyun Huang

    2014-07-01

    Full Text Available As a newly proposed theory, compressive sensing (CS is commonly used in signal processing area. This paper investigates the applications of compressed sensing (CS in wireless sensor networks (WSNs. First, the development and research status of compressed sensing technology and wireless sensor networks are described, then a detailed investigation of WSNs research based on CS are conducted from aspects of data fusion, signal acquisition, signal routing transmission, and signal reconstruction. At the end of the paper, we conclude our survey and point out the possible future research directions.

  7. Ratiometric Alcohol Sensor based on a Polymeric Nile Blue

    Directory of Open Access Journals (Sweden)

    Sherif Ibrahim

    2008-04-01

    Full Text Available We present a sterilizable ratiometric fluorescent ethanol sensor with sensitivity over a wide range (0-100% of ethanol concentration v/v. The sensor is composed of a near infra red fluorescent solvatochromic dye, nile blue methacrylamide polymerized into a polyethylene (glycol dimethacrylate matrix. The dye can typically exhibit two or more wavelength dependent shifts in the fluorescence intensities based on its different micropolar environments. Two different concentrations of the nile blue methacrylamide dye were prepared and polymerized into homogenous films. The fluorescence properties of the two different films were investigated with a view to determining their ethanol sensing capabilities. The sensor was immersed in a water-ethanol solvent mixture. Excitation of the dye was performed at 470 nm. The range of emission wavelengths was 480-800 nm. The ratio of the fluorescence intensities at 620 nm and 554 nm was obtained for ethanol concentrations varying from 0-100% and the calibration curve of the ratiometric fluorescence intensities over the entire concentration range of ethanol was plotted. A ratiometric intensity change of over 33% has been obtained for pure ethanol compared to that obtained for pure water. The sensor response was rapid (≤10 minutes. The sterilizable ethanol sensor exhibits good potential for on-line monitoring of the ethanol generated in an LB fermentation chamber.

  8. Temperature insensitive curvature sensor based on cascading photonic crystal fiber

    Science.gov (United States)

    Fu, Guangwei; Li, Yunpu; Fu, Xinghu; Jin, Wa; Bi, Weihong

    2018-03-01

    A temperature insensitive curvature sensor is proposed based on cascading photonic crystal fiber. Using the arc fusion splicing method, this sensor is fabricated by cascading together a single-mode fiber (SMF), a three layers air holes structure of photonic crystal fiber (3PCF), a five layers air holes structure of photonic crystal fiber (5PCF) and a SMF in turn. So the structure SMF-3PCF-5PCF-SMF can be obtained with a total length of 20 mm. During the process of fabrication, the splicing machine parameters and the length of each optical fiber are adjusted to obtain a high sensitivity curvature sensor. The experimental results show that the curvature sensitivity is -8.40 nm/m-1 in the curvature variation range of 0-1.09 m-1, which also show good linearity. In the range of 30-90 °C, the temperature sensitivity is only about 3.24 pm/°C, indicating that the sensor is not sensitive to temperature. The sensor not only has the advantages of easy fabricating, simple structure, high sensitivity but also can solve the problem of temperature measurement cross sensitivity, so it can be used for different areas including aerospace, large-scale bridge, architectural structure health monitoring and so on.

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

    Directory of Open Access Journals (Sweden)

    Ping Feng

    2014-09-01

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

  10. Carbon Nanotube-Based Structural Health Monitoring Sensors

    Science.gov (United States)

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

    2011-01-01

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

  11. A Blade Tip Timing Method Based on a Microwave Sensor

    Directory of Open Access Journals (Sweden)

    Jilong Zhang

    2017-05-01

    Full Text Available Blade tip timing is an effective method for blade vibration measurements in turbomachinery. This method is increasing in popularity because it is non-intrusive and has several advantages over the conventional strain gauge method. Different kinds of sensors have been developed for blade tip timing, including optical, eddy current and capacitance sensors. However, these sensors are unsuitable in environments with contaminants or high temperatures. Microwave sensors offer a promising potential solution to overcome these limitations. In this article, a microwave sensor-based blade tip timing measurement system is proposed. A patch antenna probe is used to transmit and receive the microwave signals. The signal model and process method is analyzed. Zero intermediate frequency structure is employed to maintain timing accuracy and dynamic performance, and the received signal can also be used to measure tip clearance. The timing method uses the rising and falling edges of the signal and an auto-gain control circuit to reduce the effect of tip clearance change. To validate the accuracy of the system, it is compared experimentally with a fiber optic tip timing system. The results show that the microwave tip timing system achieves good accuracy.

  12. Optofluidic refractive index sensor based on partial reflection

    Science.gov (United States)

    Zhang, Lei; Zhang, Zhang; Wang, Yichuan; Ye, Meiying; Fang, Wei; Tong, Limin

    2017-06-01

    We demonstrate a novel optofluidic refractive index (RI) sensor with high sensitivity and wide dynamic range based on partial reflection. Benefited from the divergent incident light and the output fibers with different tilting angles, we have achieved highly sensitive RI sensing in a wide range from 1.33 to 1.37. To investigate the effectiveness of this sensor, we perform a measurement of RI with a resolution of ca. 5.0×10-5 refractive index unit (RIU) for ethylene glycol solutions. Also, we have measured a series of liquid solutions by using different output fibers, achieving a resolution of ca. 0.52 mg/mL for cane surge. The optofluidic RI sensor takes advantage of the high sensitivity, wide dynamic range, small footprint, and low sample consumption, as well as the efficient fluidic sample delivery, making it useful for applications in the food industry.

  13. Pulsed electric field sensor based on original waveform measurement

    International Nuclear Information System (INIS)

    Ma Liang; Wu Wei; Cheng Yinhui; Zhou Hui; Li Baozhong; Li Jinxi; Zhu Meng

    2010-01-01

    The paper introduces the differential and original waveform measurement principles for pulsed E-field, and develops an pulsed E-field sensor based on original waveform measurement along with its theoretical correction model. The sensor consists of antenna, integrator, amplifier and driver, optic-electric/electric-optic conversion module and transmission module. The time-domain calibration in TEM cell indicates that, its risetime response is shorter than 1.0 ns, and the output pulse width at 90% of the maximum amplitude is wider than 10.0 μs. The output amplitude of the sensor is linear to the electric field intensity in a dynamic range of 20 dB. The measurement capability can be extended to 10 V/m or 50 kV/m by changing the system's antenna and other relative modules. (authors)

  14. Optical Sensor Based on a Single CdS Nanobelt

    Directory of Open Access Journals (Sweden)

    Lei Li

    2014-04-01

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

  15. Optical sensor based on a single CdS nanobelt.

    Science.gov (United States)

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

    2014-04-23

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

  16. Holographic wavefront sensor, based on diffuse Fourier holography

    Science.gov (United States)

    Gorelaya, Alina; Orlov, Vyacheslav; Venediktov, Vladimir

    2017-09-01

    Many areas of optical science and technology require fast and accurate measurement of the radiation wavefront shape. Today there are known a lot of wavefront sensor (WFS) techniques, and their number is growing up. The last years have brought a growing interest in several schematics of WFS, employing the holography principles and holographic optical elements (HOE). Some of these devices are just the improved versions of the standard and most popular Shack-Hartman WFS, while other are based on the intrinsic features of HOE. A holographic mode wavefront sensor is proposed, which makes it possible to measure up to several tens of wavefront modes. The increase in the number of measured modes is implemented using the conversion of a light wave entering the sensor into a wide diffuse light beam, which allows one to record a large number of holograms, each intended for measuring one of the modes.

  17. A piezopaint-based sensor for monitoring structure dynamics

    Science.gov (United States)

    Lahtinen, R.; Muukkonen, T.; Koskinen, J.; Hannula, S.-P.; Heczko, O.

    2007-12-01

    Piezoceramic materials are used today in a variety of applications. By combining a piezoceramic powder with paint resin it is possible to fabricate a new type of piezomaterial, which can easily be applied to almost any surface. This paper describes the development of such a paint. The thermal stability and sensitivity as a function of frequency were investigated. Furthermore, a sensor based on an optimized epoxy piezopaint having a thickness of 80 µm was fixed on a steel beam of a footbridge to study the performance of the sensor and its long-term stability. It was demonstrated that the sensor could detect signals easily both from bridge movement and from pedestrian traffic on the bridge. The signal remained constant for a period of over thirteen months of monitoring.

  18. A Neuron Model Based Ultralow Current Sensor System for Bioapplications

    Directory of Open Access Journals (Sweden)

    A. K. M. Arifuzzman

    2016-01-01

    Full Text Available An ultralow current sensor system based on the Izhikevich neuron model is presented in this paper. The Izhikevich neuron model has been used for its superior computational efficiency and greater biological plausibility over other well-known neuron spiking models. Of the many biological neuron spiking features, regular spiking, chattering, and neostriatal spiny projection spiking have been reproduced by adjusting the parameters associated with the model at hand. This paper also presents a modified interpretation of the regular spiking feature in which the firing pattern is similar to that of the regular spiking but with improved dynamic range offering. The sensor current ranges between 2 pA and 8 nA and exhibits linearity in the range of 0.9665 to 0.9989 for different spiking features. The efficacy of the sensor system in detecting low amount of current along with its high linearity attribute makes it very suitable for biomedical applications.

  19. Designing and testing a laser-based vibratory sensor

    Science.gov (United States)

    Nath, G.

    2018-04-01

    Sensor technology has proved its importance, not only in the range of few-meter applications in different fields, but in micro, nano, atomic and sub-atomic-sized objects. The present work describes the designing of a laser-based vibratory sensor using a He-Ne laser as the signal source. The received characteristics of the signal are mainly the frequency and amplitude of the vibration from which the physical parameters such as energy, power and absorption coefficients of the material are determined, which enables us to provide information of the hidden target or object. This laboratory-designed sensor finds application in different local phenomena as well as laboratory practical activity for students.

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

    Science.gov (United States)

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

    2014-03-01

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

  1. Hydrogen Gas Sensors Based on Semiconductor Oxide Nanostructures

    Directory of Open Access Journals (Sweden)

    Yongming Hu

    2012-04-01

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

  2. Photonic Crystal Fibre SERS Sensors Based on Silver Nanoparticle Colloid

    International Nuclear Information System (INIS)

    Zhi-Guo, Xie; Yong-Hua, Lu; Pei, Wang; Kai-Qun, Lin; Jie, Yan; Hai, Ming

    2008-01-01

    A photonic crystal fibre (PCF) surface enhanced Raman scattering (SERS) sensor is developed based on silver nanoparticle colloid. Analyte solution and silver nanoparticles are injected into the air holes of PCF by a simple modified syringe to overcome mass-transport constraints, allowing more silver nanoparticles involved in SERS activity. This sensor offers significant benefit over the conventional SERS sensor with high flexibility, easy manufacture. We demonstrate the detection of 4-mercaptobenzoic acid (4-MBA) molecules with the injecting way and the common dipping measurement. The injecting way shows obviously better results than the dipping one. Theoretical analysis indicates that this PCF SERS substrate offers enhancement of about 7 orders of magnitude in SERS active area

  3. Vibrissa Sensor

    Science.gov (United States)

    2016-09-30

    a seal whisker was joined at its base to a spring gimbal and subjected to flow conditions. Attorney Docket No. 300119 3 of 11 Fluid flow and the...whisker were then observed by a camera . In other research, an artificial whisker fabricated by stereolithography was fastened to a piezoelectric...the art. For example, membrane 38 could be replaced by a gimbal . The gimbal could be made from elastomeric material. Non-magnetic sensors could

  4. Palladium coated fibre Bragg grating based hydrogen sensor

    International Nuclear Information System (INIS)

    Kasinathan, M.; Sosamma, S.; Kishore, S.; Elumalai, V.; Krishnan, R.; Babu Rao, C.; Dash, Sitaram; Murali, N.; Jayakumar, T.

    2011-01-01

    Detection of steam generator leaks in fast nuclear reactors is carried out by monitoring hydrogen in argon cover-gas. Hydrogen released during sodium cleaning of fast reactor components is required to be monitored. Hydrogen sensors with good sensitivity, stability and response time are required for all the above applications. We report a new type of hydrogen sensor with a Fibre Bragg Grating (FBG) coated with palladium thin film which is used to detect the leak of hydrogen gas in the Steam Generator (SG) module of the Fast Breeder Reactor (FBR). If water leaks into sodium, it results in sodium-water reaction. In this reaction hydrogen and sodium hydroxide are formed. Due to the explosive risk of hydrogen system, hydrogen sensors are of great interest in this case. It is known that hydrogen forms an explosive mixture with air once its concentration exceeds beyond the explosion limit of four percent. The advantages of FBG based hydrogen sensor over the other hydrogen sensors are its inherent property of safety from sparking, immunity to ambient electromagnetic interference. The sensing mechanism in this device is based on mechanical strain that is induced in the palladium coating when it absorbs hydrogen. This process physically stretches the grating and causes the grating period and grating's refractive index, to change. The Bragg wavelength shift is directly proportional to the strain induced and can be directly related to the percentage of hydrogen exposure. The online monitoring of palladium thin film coating on FBG is carried out and recorded the wavelength change and strain induced on the FBG. A hydrogen sensor set up have been fabricated which consists of SS vessel of capacity 10 litres, provided with pressure gauge, Argon filling line with a valve, Hydrogen injection line with flange, a vent line with valve and Hydrogen sensor fixing point. The Palladium coated FBG based Hydrogen sensor is tested in this experimental facility in the exposure of hydrogen in

  5. Membrane-based techniques for the separation and purification of proteins: an overview.

    Science.gov (United States)

    Saxena, Arunima; Tripathi, Bijay P; Kumar, Mahendra; Shahi, Vinod K

    2009-01-30

    Membrane processes are increasingly reported for various applications in both upstream and downstream technology, such as microfiltration, ultrafiltration, emerging processes as membrane chromatography, high performance tangential flow filtration and electrophoretic membrane contactor. Membrane-based processes are playing critical role in the field of separation/purification of biotechnological products. Membranes became an integral part of biotechnology and improvements in membrane technology are now focused on high resolution of bioproduct. In bioseparation, applications of membrane technologies include protein production/purification, protein-virus separation. This manuscript provides an overview of recent developments and published literature in membrane technology, focusing on special characteristics of the membranes and membrane-based processes that are now used for the production and purification of proteins.

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

    Science.gov (United States)

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

    2015-01-01

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

  7. Tactile sensor of hardness recognition based on magnetic anomaly detection

    Science.gov (United States)

    Xue, Lingyun; Zhang, Dongfang; Chen, Qingguang; Rao, Huanle; Xu, Ping

    2018-03-01

    Hardness, as one kind of tactile sensing, plays an important role in the field of intelligent robot application such as gripping, agricultural harvesting, prosthetic hand and so on. Recently, with the rapid development of magnetic field sensing technology with high performance, a number of magnetic sensors have been developed for intelligent application. The tunnel Magnetoresistance(TMR) based on magnetoresistance principal works as the sensitive element to detect the magnetic field and it has proven its excellent ability of weak magnetic detection. In the paper, a new method based on magnetic anomaly detection was proposed to detect the hardness in the tactile way. The sensor is composed of elastic body, ferrous probe, TMR element, permanent magnet. When the elastic body embedded with ferrous probe touches the object under the certain size of force, deformation of elastic body will produce. Correspondingly, the ferrous probe will be forced to displace and the background magnetic field will be distorted. The distorted magnetic field was detected by TMR elements and the output signal at different time can be sampled. The slope of magnetic signal with the sampling time is different for object with different hardness. The result indicated that the magnetic anomaly sensor can recognize the hardness rapidly within 150ms after the tactile moment. The hardness sensor based on magnetic anomaly detection principal proposed in the paper has the advantages of simple structure, low cost, rapid response and it has shown great application potential in the field of intelligent robot.

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

    Science.gov (United States)

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

    2015-02-04

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

  9. Continuous Membrane-Based Screening System for Biocatalysis

    Directory of Open Access Journals (Sweden)

    Matthias Kraume

    2011-02-01

    Full Text Available The use of membrane reactors for enzymatic and co-factor regenerating reactions offers versatile advantages such as higher conversion rates and space-time-yields and is therefore often applied in industry. However, currently available screening and kinetics characterization systems are based on batch and fed-batch operated reactors and were developed for whole cell biotransformations rather than for enzymatic catalysis. Therefore, the data obtained from such systems has only limited transferability for continuous membrane reactors. The aim of this study is to evaluate and to improve a novel screening and characterization system based on the membrane reactor concept using the enzymatic hydrolysis of cellulose as a model reaction. Important aspects for the applicability of the developed system such as long-term stability and reproducibility of continuous experiments were very high. The concept used for flow control and fouling suppression allowed control of the residence time with a high degree of precision (±1% accuracy in a long-term study (>100 h.

  10. MEMS-Based Fuel Reformer with Suspended Membrane Structure

    Science.gov (United States)

    Chang, Kuei-Sung; Tanaka, Shuji; Esashi, Masayoshi

    We report a MEMS-based fuel reformer for supplying hydrogen to micro-fuel cells for portable applications. A combustor and a reforming chamber are fabricated at either side of a suspended membrane structure. This design is used to improve the overall thermal efficiency, which is a critical issue to realize a micro-fuel reformer. The suspended membrane structure design provided good thermal isolation. The micro-heaters consumed 0.97W to maintain the reaction zone of the MEMS-based fuel reformer at 200°C, but further power saving is necessary by improving design and fabrication. The conversion rate of methanol to hydrogen was about 19% at 180°C by using evaporated copper as a reforming catalyst. The catalytic combustion of hydrogen started without any assistance of micro-heaters. By feeding the fuel mixture of an equivalence ratio of 0.35, the temperature of the suspended membrane structure was maintained stable at 100°C with a combustion efficiency of 30%. In future works, we will test a micro-fuel reformer by using a micro-combustor to supply heat.

  11. Multiset-based Tree Model for Membrane Computing

    Directory of Open Access Journals (Sweden)

    D. Singh

    2011-06-01

    Full Text Available In this paper, we introduce a new paradigm - multiset-based tree model. We show that trees can be represented in the form of wellfounded multisets. We also show that the conventional approach for this representation is not injective from a set of trees to the class of multisets representing such trees. We establish a one-to-one correspondence between trees and suitable permutations of a wellfounded multiset, which we call \\textit{tree structures}. We give formal definitions of a \\textit{tree structure} and a \\textit{subtree structure} of a tree structure. Finally, we represent membrane structures in the form of tree structures - a form in which membrane structures can suitably be represented at programming level.

  12. Paper-Based Sensor Chip for Heavy Metal Ion Detection by SWSV

    Directory of Open Access Journals (Sweden)

    Xiaoqing Wang

    2018-03-01

    Full Text Available Heavy metal ion pollution problems have had a terrible influence on human health and the environment. Therefore, the monitoring of heavy metal ions is of great practical significance. In this paper, an electrochemical three-electrode system was fabricated and integrated on nitrocellulose membrane (NC by the use of magnetron sputtering technology, which exhibited a uniform arrangement of porous structure without further film modification. This paper-based sensor chip was used for Cu2+ detection by square-wave stripping voltammetry (SWSV. Within the ranges of 5~200 μg·L−1 and 200~1000 μg·L−1, it showed good linearity of 99.58% and 98.87%, respectively. The limit of detection was 2 μg·L−1. On the basis of satisfying the detection requirements (10 μg·L−1, the integrated sensor was small in size and inexpensive in cost. Zn2+, Cd2+, Pb2+ and Bi3+ were also detected by this paper-based sensor chip with good linearity.

  13. Solid-contact potentiometric sensor for ascorbic acid based on cobalt phthalocyanine nanoparticles as ionophore.

    Science.gov (United States)

    Wang, Kun; Xu, Jing-Juan; Tang, Kai-Shi; Chen, Hong-Yuan

    2005-10-15

    A novel solid-contact potentiometric sensor for ascorbic acid based on cobalt phthalocyanine nanoparticles (NanoCoPc) as ionophore was fabricated without any need of auxiliary materials (such as membrane matrix, plasticizer, and other additives). The electrode was prepared by simple drop-coating NanoCoPc colloid on the surface of a glassy carbon electrode. A smooth, bright and blue thin film was strongly attached on the surface of the glassy carbon electrode. The electrode showed high selectivity for ascorbic acid, as compared with many common anions. The influences of the amount of NanoCoPc at the electrode surface and pH on the response characteristics of the electrode were investigated. To overcome the instability of the formal potential of the coated wire electrode, a novel electrochemical pretreatment method was proposed for the potentiometric sensor based on redox mechanism. This resulting sensor demonstrates potentiometric response over a wide linear range of ascorbic acid concentration (5.5 x 10(-7) to 5.5 x 10(-2)M) with a fast response (determination of practical samples.

  14. Composite Si/PS membrane pressure sensors with micro and macro ...

    Indian Academy of Sciences (India)

    Abstract. Porous Silicon (PS) is a versatile material with many unique features making it viable in the field of Microelectromechanical Systems (MEMS). In this paper, we discuss the optimization of formation parameters of micro and macro. PS with different porosity and thickness for use in pressure sensors. The optimized.

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

    Science.gov (United States)

    Nallon, Eric C.

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

  16. ppt level detection of samarium(III) with a coated graphite sensor based on an antibiotic.

    Science.gov (United States)

    Ganjali, Mohammad Reza; Rezapour, Morteza; Pourjavid, Mohammad Reza; Haghgoo, Soheila

    2004-07-01

    N-[2-[4-[[[(Cyclohexylamino)carbonyl]amino]sulfonyl]phenyl]ethyl]-5-methyl pyrazine carboxamide (glipizid) was explored as an electro-active material for preparing a polymeric membrane-based sensor selective to samarium ions. The membrane incorporated 30% poly(vinyl chloride) (PVC), 53% benzyl acetate (BA), 11% glipizid and 6% sodium tetraphenyl borate. When coated on the surface of a graphite electrode, it exhibits Nernstian responses in the concentration range of 1.0 x 10(-5) to 1.0 x 10(-10) M, with a detection limit of 8.0 x 10(-11)M samarium. The electrode shows high selectivity towards samarium over several cations (alkali, alkaline earth, transition and heavy metal ions), and specially lanthanide ions. The proposed sensor has a very short response time (pH range for at least ten weeks. It was used as an indicator electrode in potentiometric titration of Sm(III) ions with an EDTA solution, and for determination of samarium in binary and ternary mixtures.

  17. A μ-biomimetic uncooled infrared sensor based on the infrared receptors of Melanophila acuminata

    International Nuclear Information System (INIS)

    Siebke, Georg

    2015-11-01

    The pyrophilous beetle Melanophila acuminata possesses an organ sensitive to IR radiation. It employs a photomechanic detection principle: A liquid filled pressure chamber is heated by absorbing the radiation. The liquid expands and leads to the deflection of a mechanosensitive dendrite. In addition, a sophisticated compensation mechanism prevents the build-up of large pressures. In this work, a biomimetic IR sensor based on the IR receptors of Melanophila acuminata is developed by means of microsystems technology. The sensor consists of two liquid-filled chambers that are connected by a micro-fluidic system. Absorption of IR radiation by one of the chambers leads to the heating and expansion of a liquid. The increasing pressure deflects a membrane which is part of a plate capacitor with a diameter of 500 μm and an electrode distance of 500 nm. The micro-fluidic system and the second chamber represent a fluidic low-pass filter, preventing slow, but large pressure changes. A theoretical model is developed which is able to predict the modulation frequency dependent response. It allows to calculate the filter properties of the compensation mechanism which is verified by an experimental test. A simplified sensor without the compensation mechanism is manufactured to analyse the influence of several parameters on the sensor's sensitivity. Finally, a solution for the fabrication of the μ-capacitor is presented. The large aspect ratio between electrode diameter and distance prevents to use a standard sacrificial layer process. The obtained capacitors pave the way to fabricate the complete full-featured sensor.

  18. A μ-biomimetic uncooled infrared sensor based on the infrared receptors of Melanophila acuminata

    Energy Technology Data Exchange (ETDEWEB)

    Siebke, Georg

    2015-11-15

    The pyrophilous beetle Melanophila acuminata possesses an organ sensitive to IR radiation. It employs a photomechanic detection principle: A liquid filled pressure chamber is heated by absorbing the radiation. The liquid expands and leads to the deflection of a mechanosensitive dendrite. In addition, a sophisticated compensation mechanism prevents the build-up of large pressures. In this work, a biomimetic IR sensor based on the IR receptors of Melanophila acuminata is developed by means of microsystems technology. The sensor consists of two liquid-filled chambers that are connected by a micro-fluidic system. Absorption of IR radiation by one of the chambers leads to the heating and expansion of a liquid. The increasing pressure deflects a membrane which is part of a plate capacitor with a diameter of 500 μm and an electrode distance of 500 nm. The micro-fluidic system and the second chamber represent a fluidic low-pass filter, preventing slow, but large pressure changes. A theoretical model is developed which is able to predict the modulation frequency dependent response. It allows to calculate the filter properties of the compensation mechanism which is verified by an experimental test. A simplified sensor without the compensation mechanism is manufactured to analyse the influence of several parameters on the sensor's sensitivity. Finally, a solution for the fabrication of the μ-capacitor is presented. The large aspect ratio between electrode diameter and distance prevents to use a standard sacrificial layer process. The obtained capacitors pave the way to fabricate the complete full-featured sensor.

  19. Influence of temperature and humidity on carbon based printed flexible sensors

    KAUST Repository

    Nag, Anindya

    2018-03-02

    This paper presents the response of two different types of novel printed sensors towards the change in temperature and humidity. The electrodes of all the sensors were based on carbon materials. Followed by the design and fabrication of the sensors, the responses of the sensors were analyzed for different temperature and humidity conditions in an incubator. These results provide a podium to enhance the alternation of the fabrication procedure of carbon-based printed sensors.

  20. IBE-Lite: a lightweight identity-based cryptography for body sensor networks.

    Science.gov (United States)

    Tan, Chiu C; Wang, Haodong; Zhong, Sheng; Li, Qun

    2009-11-01

    A body sensor network (BSN) is a network of sensors deployed on a person's body for health care monitoring. Since the sensors collect personal medical data, security and privacy are important components in a BSN. In this paper, we developed IBE-Lite, a lightweight identity-based encryption suitable for sensors in a BSN. We present protocols based on IBE-Lite that balance security and privacy with accessibility and perform evaluation using experiments conducted on commercially available sensors.

  1. A Survey of Model-based Sensor Data Acquisition and Management

    OpenAIRE

    Aggarwal, Charu C.; Sathe, Saket; Papaioannou, Thanasis; Jeung, Hoyoung; Aberer, Karl

    2013-01-01

    In recent years, due to the proliferation of sensor networks, there has been a genuine need of researching techniques for sensor data acquisition and management. To this end, a large number of techniques have emerged that advocate model-based sensor data acquisition and management. These techniques use mathematical models for performing various, day-to-day tasks involved in managing sensor data. In this chapter, we survey the state-of-the-art techniques for model-based sensor data acquisition...

  2. Smart sensor-based geospatial architecture for dike monitoring

    Science.gov (United States)

    Herle, S.; Becker, R.; Blankenbach, J.

    2016-04-01

    Artificial hydraulic structures like dams or dikes used for water level regulations or flood prevention are continuously under the influence of the weather and variable river regimes. Thus, ongoing monitoring and simulation is crucial in order to determine the inner condition. Potentially life-threatening situations, in extreme case a failure, must be counteracted by all available means. Nowadays flood warning systems rely exclusively on water level forecast without considering the state of the structure itself. Area-covering continuous knowledge of the inner state including time dependent changes increases the capability of recognizing and locating vulnerable spots for early treatment. In case of a predicted breach, advance warning time for alerting affected citizens can be extended. Our approach is composed of smart sensors integrated in a service-oriented geospatial architecture to monitor and simulate artificial hydraulic structures continuously. The sensors observe the inner state of the construction like the soil moisture or the stress and deformation over time but also various external influences like water levels or wind speed. They are interconnected in distributed network architecture by a so-called sensor bus system based on lightweight protocols like Message Queue Telemetry Transport for Sensor Networks (MQTT-SN). These sensor data streams are transferred into an OGC Sensor Web Enablement (SWE) data structure providing high-level geo web services to end users. Bundled with 3rd party geo web services (WMS etc.) powerful processing and simulation tools can be invoked using the Web Processing Service (WPS) standard. Results will be visualized in a geoportal allowing user access to all information.

  3. Development of a soil detector based on an optical sensor

    Science.gov (United States)

    Zheng, Lihua; Pan, Luan; Li, Minzan; An, Xiaofei

    2008-12-01

    An estimation model of the soil organic matter content has been built based on NIR spectroscopy and a portable soil organic matter detector based on optical sensor is developed. The detector uses a micro processor 89S52 as the Micro Controller Unit (MCU) and consists of an optical system and a control system. The optical system includes a 850nm near-infrared lamp-house, a lamp-house driving-circuit, a Y type optical fiber, a probe, and a photoelectric sensor. The control system includes an amplified circuit, an A/D circuit, a display circuit with LCD, and a storage circuit with USB interface. Firstly the single waveband optical signal from the near-infrared lamp-house is transferred to the surface of the target soil via the incidence fibers. Then the reflected optical signal is collected and transferred to photoelectric sensor, where the optical signal is conveyed to the electrical signal. Subsequently, the obtained electrical signal is processed by 89S52 MCU. Finally, the calculated soil organic matter content is displayed on the LCD and stored in the USB disk. The calibration experiment using the estimation model of the soil organic matter is conducted. The decision coefficient (R2) reaches 0.9839 between the measured data by the soil organic matter sensor and by the laboratory chemistry method.

  4. A ferrofluid based artificial tactile sensor with magnetic field control

    International Nuclear Information System (INIS)

    Volkova, T.I.; Böhm, V.; Naletova, V.A.; Kaufhold, T.; Becker, F.; Zeidis, I.; Zimmermann, K.

    2017-01-01

    The paper deals with a tactile sensor inspired by biological hairs of mammals. The working principle is based on the effect of the magnetic force exerted on a paramagnetic body submerged into a ferrofluid volume under the influence of a nonuniform magnetic field. The deflection of the sensor's rod caused by external mechanical stimuli may be unambiguously identified by the distortion of the magnetic field, which occurs due to the motion of the attached body in the ferrofluid. The magnetic force acting on the body is evaluated experimentally and theoretically for the nonuniform magnetic field of a permanent magnet. The controlled oscillations of the rod are realised by applying a nonuniform magnetic field of periodically altering direction. - Highlights: • A design approach of a tactile sensor inspired by special mammalian hairs is presented. • The working principle is based on magnetic properties of a ferrofluid in magnetic fields. • The magnetic force acting on a body submerged into a ferrofluid volume is evaluated. • External mechanical stimuli may be identified by the distortion of the magnetic field. • The controlled whisking-like oscillations of the sensor's rod are realised experimentally.

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

    Science.gov (United States)

    Wei, Heming; Tao, Chuanyi; Krishnaswamy, Sridhar

    2016-04-01

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

  6. A ferrofluid based artificial tactile sensor with magnetic field control

    Energy Technology Data Exchange (ETDEWEB)

    Volkova, T.I., E-mail: tatiana.volkova@tu-ilmenau.de [Technical Mechanics Group, Faculty of Mechanical Engineering, Technische Universität Ilmenau, Ilmenau D-98684 (Germany); Böhm, V., E-mail: valter.boehm@tu-ilmenau.de [Technical Mechanics Group, Faculty of Mechanical Engineering, Technische Universität Ilmenau, Ilmenau D-98684 (Germany); Naletova, V.A., E-mail: naletova@imec.msu.ru [Faculty of Mechanics and Mathematics, Lomonosov Moscow State University, 119991 Moscow (Russian Federation); Kaufhold, T., E-mail: tobias.kaufhold@tu-ilmenau.de [Technical Mechanics Group, Faculty of Mechanical Engineering, Technische Universität Ilmenau, Ilmenau D-98684 (Germany); Becker, F., E-mail: felix.becker@tu-ilmenau.de [Technical Mechanics Group, Faculty of Mechanical Engineering, Technische Universität Ilmenau, Ilmenau D-98684 (Germany); Zeidis, I., E-mail: igor.zeidis@tu-ilmenau.de [Technical Mechanics Group, Faculty of Mechanical Engineering, Technische Universität Ilmenau, Ilmenau D-98684 (Germany); Zimmermann, K., E-mail: klaus.zimmermann@tu-ilmenau.de [Technical Mechanics Group, Faculty of Mechanical Engineering, Technische Universität Ilmenau, Ilmenau D-98684 (Germany)

    2017-06-01

    The paper deals with a tactile sensor inspired by biological hairs of mammals. The working principle is based on the effect of the magnetic force exerted on a paramagnetic body submerged into a ferrofluid volume under the influence of a nonuniform magnetic field. The deflection of the sensor's rod caused by external mechanical stimuli may be unambiguously identified by the distortion of the magnetic field, which occurs due to the motion of the attached body in the ferrofluid. The magnetic force acting on the body is evaluated experimentally and theoretically for the nonuniform magnetic field of a permanent magnet. The controlled oscillations of the rod are realised by applying a nonuniform magnetic field of periodically altering direction. - Highlights: • A design approach of a tactile sensor inspired by special mammalian hairs is presented. • The working principle is based on magnetic properties of a ferrofluid in magnetic fields. • The magnetic force acting on a body submerged into a ferrofluid volume is evaluated. • External mechanical stimuli may be identified by the distortion of the magnetic field. • The controlled whisking-like oscillations of the sensor's rod are realised experimentally.

  7. Corrosion Sensor Development for Condition-Based Maintenance of Aircraft

    Directory of Open Access Journals (Sweden)

    Gino Rinaldi

    2012-01-01

    Full Text Available Aircraft routinely operate in atmospheric environments that, over time, will impact their structural integrity. Material protection and selection schemes notwithstanding, recurrent exposure to chlorides, pollution, temperature gradients, and moisture provide the necessary electrochemical conditions for the development and profusion of corrosion in aircraft structures. For aircraft operators, this becomes an important safety matter as corrosion found in a given aircraft must be assumed to be present in all of that type of aircraft. This safety protocol and its associated unscheduled maintenance requirement drive up the operational costs of the fleet and limit the availability of the aircraft. Hence, there is an opportunity at present for developing novel sensing technologies and schemes to aid in shifting time-based maintenance schedules towards condition-based maintenance procedures. In this work, part of the ongoing development of a multiparameter integrated corrosion sensor is presented. It consists of carbon nanotube/polyaniline polymer sensors and commercial-off-the-shelf sensors. It is being developed primarily for monitoring environmental and material factors for the purpose of providing a means to more accurately assess the structural integrity of aerospace aluminium alloys through fusion of multiparameter sensor data. Preliminary experimental test results are presented for chloride ion concentration, hydrogen gas evolution, humidity variations, and material degradation.

  8. Model based, sensor directed remediation of underground storage tanks

    International Nuclear Information System (INIS)

    Christensen, B.; Drotning, W.; Thunborg, S.

    1991-01-01

    Sensor rich, intelligent robots which function with respect to models of their environment have significant potential to reduce the time and cost for the cleanup of hazardous waste while increasing operator safety. Sandia National Laboratories is performing experimental investigations into the application of intelligent robot control technology to the problem of removing waste stored tanks. This paper describes the experimental environment employed at Saudi with particular attention to the computing and software control environment. Intelligent system control is achieved though the integration of extensive geometric and kinematic world models with real-time sensor based control. All operator interactions with the system are validate all operator commands before execution to provide a safe operation. Sensing is used to add information to the robot system's world model and to allow sensor based sensor control during selected operations. The results of a first Critical Feature Test are reported and the potential for applying advanced intelligent control concepts to the removal of waste in storage tanks is discussed

  9. Monitoring and Control Interface Based on Virtual Sensors

    Directory of Open Access Journals (Sweden)

    Ricardo F. Escobar

    2014-10-01

    Full Text Available In this article, a toolbox based on a monitoring and control interface (MCI is presented and applied in a heat exchanger. The MCI was programed in order to realize sensor fault detection and isolation and fault tolerance using virtual sensors. The virtual sensors were designed from model-based high-gain observers. To develop the control task, different kinds of control laws were included in the monitoring and control interface. These control laws are PID, MPC and a non-linear model-based control law. The MCI helps to maintain the heat exchanger under operation, even if a temperature outlet sensor fault occurs; in the case of outlet temperature sensor failure, the MCI will display an alarm. The monitoring and control interface is used as a practical tool to support electronic engineering students with heat transfer and control concepts to be applied in a double-pipe heat exchanger pilot plant. The method aims to teach the students through the observation and manipulation of the main variables of the process and by the interaction with the monitoring and control interface (MCI developed in LabVIEW©. The MCI provides the electronic engineering students with the knowledge of heat exchanger behavior, since the interface is provided with a thermodynamic model that approximates the temperatures and the physical properties of the fluid (density and heat capacity. An advantage of the interface is the easy manipulation of the actuator for an automatic or manual operation. Another advantage of the monitoring and control interface is that all algorithms can be manipulated and modified by the users.

  10. Thermal-Signature-Based Sleep Analysis Sensor

    Directory of Open Access Journals (Sweden)

    Ali Seba

    2017-10-01

    Full Text Available This paper addresses the development of a new technique in the sleep analysis domain. Sleep is defined as a periodic physiological state during which vigilance is suspended and reactivity to external stimulations diminished. We sleep on average between six and nine hours per night and our sleep is composed of four to six cycles of about 90 min each. Each of these cycles is composed of a succession of several stages of sleep that vary in depth. Analysis of sleep is usually done via polysomnography. This examination consists of recording, among other things, electrical cerebral activity by electroencephalography (EEG, ocular movements by electrooculography (EOG, and chin muscle tone by electromyography (EMG. Recordings are made mostly in a hospital, more specifically in a service for monitoring the pathologies related to sleep. The readings are then interpreted manually by an expert to generate a hypnogram, a curve showing the succession of sleep stages during the night in 30s epochs. The proposed method is based on the follow-up of the thermal signature that makes it possible to classify the activity into three classes: “awakening,” “calm sleep,” and “restless sleep”. The contribution of this non-invasive method is part of the screening of sleep disorders, to be validated by a more complete analysis of the sleep. The measure provided by this new system, based on temperature monitoring (patient and ambient, aims to be integrated into the tele-medicine platform developed within the framework of the Smart-EEG project by the SYEL–SYstèmes ELectroniques team. Analysis of the data collected during the first surveys carried out with this method showed a correlation between thermal signature and activity during sleep. The advantage of this method lies in its simplicity and the possibility of carrying out measurements of activity during sleep and without direct contact with the patient at home or hospitals.

  11. An adhesion-based method for plasma membrane isolation: evaluating cholesterol extraction from cells and their membranes.

    Science.gov (United States)

    Bezrukov, Ludmila; Blank, Paul S; Polozov, Ivan V; Zimmerberg, Joshua

    2009-11-15

    A method to isolate large quantities of directly accessible plasma membrane from attached cells is presented. The method is based on the adhesion of cells to an adsorbed layer of polylysine on glass plates, followed by hypotonic lysis with ice-cold distilled water and subsequent washing steps. Optimal conditions for coating glass plates and time for cell attachment were established. No additional chemical or mechanical treatments were used. Contamination of the isolated plasma membrane by cell organelles was less than 5%. The method uses inexpensive, commercially available polylysine and reusable glass plates. Plasma membrane preparations can be made in 15 min. Using this method, we determined that methyl-beta-cyclodextrin differentially extracts cholesterol from fibroblast cells and their plasma membranes and that these differences are temperature dependent. Determination of the cholesterol/phospholipid ratio from intact cells does not reflect methyl-beta-cyclodextrin plasma membrane extraction properties.

  12. Fluorine NMR-based screening on cell membrane extracts.

    Science.gov (United States)

    Veronesi, Marina; Romeo, Elisa; Lambruschini, Chiara; Piomelli, Daniele; Bandiera, Tiziano; Scarpelli, Rita; Garau, Gianpiero; Dalvit, Claudio

    2014-02-01

    The possibility of measuring the action of inhibitors of specific enzymatic reactions in intact cells, cell lysates or membrane preparations represents a major advance in the lead discovery process. Despite the relevance of assaying in physiological conditions, only a small number of biophysical techniques, often requiring complex set-up, are applicable to these sample types. Here, we demonstrate the first application of n-fluorine atoms for biochemical screening (n-FABS), a homogeneous and versatile assay based on (19) F NMR spectroscopy, to the detection of high- and low-affinity inhibitors of a membrane enzyme in cell extracts and determination of their IC50 values. Our approach can allow the discovery of novel binding fragments against targets known to be difficult to purify or where membrane-association is required for activity. These results pave the way for future applications of the methodology to these relevant and complex biological systems. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Artificial plasma membrane models based on lipidomic profiling.

    Science.gov (United States)

    Essaid, Donia; Rosilio, Véronique; Daghildjian, Katia; Solgadi, Audrey; Vergnaud, Juliette; Kasselouri, Athena; Chaminade, Pierre

    2016-11-01

    Phospholipid monolayers are often described as membrane models for analyzing drug-lipid interactions. In many works, a single phosphatidylcholine is chosen, sometimes with one or two additional components. Drug penetration is studied at 30mN/m, a surface pressure considered as corresponding to the pressure in bilayers, independently of the density of lipid molecular packing. In this work, we have extracted, identified, and quantified the major lipids constituting the lipidome of plasma and mitochondrial membranes of retinoblastoma (Y79) and retinal pigment epithelium cells (ARPE-19), using liquid chromatography coupled to high-resolution mass spectrometry (LC-MS/MS). The results obtained from this lipidomic analysis were used in an attempt to build an artificial lipid monolayer with a composition mimicking that of the plasma membrane of Y79 cells, better than a single phospholipid. The variety and number of lipid classes and species in cell extracts monolayers exceeding by far those of the phospholipids chosen to mimic them, the π-A isotherms of model monolayers differed from those of lipid extracts in shape and apparent packing density. We propose a model monolayer based on the most abundant species identified in the extracts, with a surface compressional modulus at 30mN/m close to the one of the lipid extracts. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Immobilization of ionophore and surface characterization studies of the titanium(III) ion in a PVC-membrane sensor.

    Science.gov (United States)

    Rezayi, Majid; Heng, Lee Yook; Kassim, Anuar; Ahmadzadeh, Saeid; Abdollahi, Yadollah; Jahangirian, Hossein

    2012-01-01

    Novel ionophores comprising various hydroxide and amine structures were immobilized onto poly(vinyl chloride) (PVC) matrices, and these were examined to determine Ti(III) selectivity. To predict the selectivity of Ti(III), a PVC membrane was used to investigate the binding of Ti(III) to c-methylcalix[4]resorcinarene (CMCR). The study showed that the chelating ligand, CMCR, was coordinated selectively to Ti(III) at eight coordination sites involving the oxygen atoms at the interface of the membrane/solution. The membrane was prepared, based on CMCR as an ionophore, sodium tetrakis(4-fluorophenyl) borate (NaTFPB) as a lipophilic ionic additive, and dioctylphthalate (DOP) as a plasticizer. The immobilization of the ionophore and surface characterization studies revealed that the performance of CMCR-immobilized PVC was equivalent to that of mobile ionophores in supported liquid membranes (SLMs). The strengths of the ion-ionophore (CMCR-Ti(OH)(OH(2))(5) (2+)) interactions and the role of ionophores on membranes were studied via UV-Vis, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and and X-ray diffraction (XRD).

  15. Load monitoring using a calibrated piezo diaphragm based impedance strain sensor and wireless sensor network in real time

    Science.gov (United States)

    Gopal Madhav Annamdas, Venu; Kiong Soh, Chee

    2017-04-01

    The last decade has seen the use of various wired-wireless and contact-contactless sensors in several structural health monitoring (SHM) techniques. Most SHM sensors that are predominantly used for strain measurements may be ineffective for damage detection and vice versa, indicating the uniapplicability of these sensors. However, piezoelectric (PE)-based macro fiber composite (MFC) and lead zirconium titanate (PZT) sensors have been on the rise in SHM, vibration and damping control, etc, due to their superior actuation and sensing abilities. These PE sensors have created much interest for their multi-applicability in various technologies such as electromechanical impedance (EMI)-based SHM. This research employs piezo diaphragms, a cheaper alternative to several expensive types of PZT/MFC sensors for the EMI technique. These piezo diaphragms were validated last year for their applicability in damage detection using the frequency domain. Here we further validate their applicability in strain monitoring using the real time domain. Hence, these piezo diaphragms can now be classified as PE sensors and used with PZT and MFC sensors in the EMI technique for monitoring damage and loading. However, no single technique or single type of sensor will be sufficient for large SHM, thus requiring the necessary deployment of more than one technique with different types of sensors such as a piezoresistive strain gauge based wireless sensor network for strain measurements to complement the EMI technique. Furthermore, we present a novel procedure of converting a regular PE sensor in the ‘frequency domain’ to ‘real time domain’ for strain applications.

  16. Colorimetric detection of Cr (VI) based on the leaching of gold nanoparticles using a paper-based sensor.

    Science.gov (United States)

    Guo, Jian-Feng; Huo, Dan-Qun; Yang, Mei; Hou, Chang-Jun; Li, Jun-Jie; Fa, Huan-Bao; Luo, Hui-Bo; Yang, Ping

    2016-12-01

    Herein, we have developed a simple, sensitive and paper-based colorimetric sensor for the selective detection of Chromium (Ⅵ) ions (Cr (VI)). Silanization-titanium dioxide modified filter paper (STCP) was used to trap bovine serum albumin capped gold nanoparticles (BSA-Au NPs), leading to the fabrication of BSA-Au NPs decorated membrane (BSA-Au NPs/STCP). The BSA-Au NPs/STCP operated on the principle that BSA-Au NPs anchored on the STCP were gradually etched by Cr (VI) as the leaching process of gold in the presence of hydrobromic acid (HBr) and hence induced a visible color change. Under optimum conditions, the paper-based colorimetric sensor showed clear color change after reaction with Cr (VI) as well as with favorable selectivity to a variety of possible interfering counterparts. The amount-dependent colorimetric response was linearly correlated with the Cr (VI) concentrations ranging from 0.5µM to 50.0µM with a detection limit down to 280nM. Moreover, the developed cost-effective colorimetric sensor has been successfully applied to real environmental samples which demonstrated the potential for field applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Flat Panel Space Based Space Surveillance Sensor

    Science.gov (United States)

    Kendrick, R.; Duncan, A.; Wilm, J.; Thurman, S. T.; Stubbs, D. M.; Ogden, C.

    2013-09-01

    Traditional electro-optical (EO) imaging payloads consist of an optical telescope to collect the light from the object scene and map the photons to an image plane to be digitized by a focal plane detector array. The size, weight, and power (SWaP) for the traditional EO imager is dominated by the optical telescope, driven primarily by the large optics, large stiff structures, and the thermal control needed to maintain precision free-space optical alignments. We propose a non-traditional Segmented Planar Imaging Detector for EO Reconnaissance (SPIDER) imager concept that is designed to substantially reduce SWaP, by at least an order of magnitude. SPIDER maximizes performance by providing a larger effective diameter (resolution) while minimizing mass and cost. SPIDER replaces the traditional optical telescope and digital focal plane detector array with a densely packed interferometer array based on emerging photonic integrated circuit (PIC) technologies. Lenslets couple light from the object into a set of waveguides on a PIC. Light from each lenslet is distributed among different waveguides by both field angle and optical frequency, and the lenslets are paired up to form unique interferometer baselines by combining light from different waveguides. The complex spatial coherence of the object (for each field angle, frequency, and baseline) is measured with a balanced four quadrature detection scheme. By the Van-Cittert Zernike Theorem, each measurement corresponds to a unique Fourier component of the incoherent object intensity distribution. Finally, an image reconstruction algorithm is used to invert all the data and form an image. Our approach replaces the large optics and structures required by a conventional telescope with PICs that are accommodated by standard lithographic fabrication techniques (e.g., CMOS fabrication). The standard EO payload integration and test process which involves precision alignment and test of optical components to form a diffraction

  18. Wheel-Based Ice Sensors for Road Vehicles

    Science.gov (United States)

    Arndt, G. Dickey; Fink, Patrick W.; Ngo, Phong H.; Carl, James R.

    2011-01-01

    Wheel-based sensors for detection of ice on roads and approximate measurement of the thickness of the ice are under development. These sensors could be used to alert drivers to hazardous local icing conditions in real time. In addition, local ice-thickness measurements by these sensors could serve as guidance for the minimum amount of sand and salt required to be dispensed locally onto road surfaces to ensure safety, thereby helping road crews to utilize their total supplies of sand and salt more efficiently. Like some aircraft wing-surface ice sensors described in a number of previous NASA Tech Briefs articles, the wheelbased ice sensors are based, variously, on measurements of changes in capacitance and/or in radio-frequency impedance as affected by ice on surfaces. In the case of ice on road surfaces, the measurable changes in capacitance and/or impedance are attributable to differences among the electric permittivities of air, ice, water, concrete, and soil. In addition, a related phenomenon that can be useful for distinguishing between ice and water is a specific transition in the permittivity of ice at a temperature- dependent frequency. This feature also provides a continuous calibration of the sensor to allow for changing road conditions. Several configurations of wheel-based ice sensors are under consideration. For example, in a simple two-electrode capacitor configuration, one of the electrodes would be a circumferential electrode within a tire, and the ground would be used as the second electrode. Optionally, the steel belts that are already standard parts of many tires could be used as the circumferential electrodes. In another example (see figure), multiple electrodes would be embedded in rubber between the steel belt and the outer tire surface. These electrodes would be excited in alternating polarities at one or more suitable audio or radio frequencies to provide nearly continuous monitoring of the road surface under the tire. In still another

  19. Integrated radar-photometry sensor based on constrained optical flow

    Science.gov (United States)

    Fablet, Youenn; Agam, Gady; Cohen, Paul

    2000-06-01

    Robotic teleoperation is a major research area with numerous applications. Efficient teleoperation, however, greatly depends on the provided sensory information. In this paper, an integrated radar- photometry sensor is presented. The developed sensor relies on the strengths of the two main modalties: robust radar-based range data, and high resolution dynamic photometric imaging. While radar data has low resolution and depth from motion in photometric images is susceptible to poor visibility conditions, the integrated sensor compensates for the flaws of the individual components. The integration of the two modalities is achieved by us ing the radar based range data in order to constrain the optical flow estimation, and fusing the resulting depth maps. The optical flow computation is constrained by a model flow field based upon the radar data, by using a rigidity constraint, and by incorporating edge information into the optical flow estimation. The data fusion is based upon a confidence estimation of the image based depth computation. Results with simulated data demonstrate the good potential of the approach.

  20. Adhesion force sensing and activation of a membrane-bound sensor to activate nisin efflux pumps in Staphylococcus aureus under mechanical and chemical stresses

    NARCIS (Netherlands)

    Carniello, Vera; Harapanahalli, Akshay K.; Busscher, Henk J.; van der Mei, Henny C.

    2018-01-01

    Nisin-associated-sensitivity-response-regulator (NsaRS) in Staphylococcus aureus is important for its adhesion to surfaces and resistance against antibiotics, like nisin. NsaRS consists of an intra-membrane-located sensor NsaS and a cytoplasmatically-located response-regulator NsaR, which becomes