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Sample records for single-nanoparticle oxygen sensors

  1. Single Nanoparticle Plasmonic Sensors

    Manish Sriram

    2015-10-01

    Full Text Available The adoption of plasmonic nanomaterials in optical sensors, coupled with the advances in detection techniques, has opened the way for biosensing with single plasmonic particles. Single nanoparticle sensors offer the potential to analyse biochemical interactions at a single-molecule level, thereby allowing us to capture even more information than ensemble measurements. We introduce the concepts behind single nanoparticle sensing and how the localised surface plasmon resonances of these nanoparticles are dependent upon their materials, shape and size. Then we outline the different synthetic approaches, like citrate reduction, seed-mediated and seedless growth, that enable the synthesis of gold and silver nanospheres, nanorods, nanostars, nanoprisms and other nanostructures with tunable sizes. Further, we go into the aspects related to purification and functionalisation of nanoparticles, prior to the fabrication of sensing surfaces. Finally, the recent developments in single nanoparticle detection, spectroscopy and sensing applications are discussed.

  2. Novel nanostructured oxygen sensor

    Boardman, Alan James

    New government regulations and industry requirements for medical oxygen sensors require the development of alternate materials and process optimization of primary sensor components. Current oxygen sensors are not compliant with the Restriction of Hazardous Substances (RoHS) Directive. This work focused on two areas. First, was finding suitable readily available materials for the sensor anodes. Second was optimizing the processing of the sensor cathode membrane for reduced delamination. Oxygen sensors were made using tin (Sn) and bismuth (Bi) electrodes, potassium hydroxide (KOH) and acetic acid (CH3COOH) electrolytes with platinum (Pt) and gold (Au) reference electrodes. Bi electrodes were fabricated by casting and pressing processes. Electrochemical characterization of the Sn and Bi electrodes was performed by Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and sensing characterization per BSEN ISO 21647:2009 at various oxygen percentages, 0%, 20.9% and 100% oxygen levels with an automated test apparatus. The Sn anode with both electrolyte solutions showed good oxygen sensing properties and performance in a sensor. This system shows promise for replacement of Pb electrodes as required by the RoHS Directive. The Bi anode with Au cathode in both KOH and CH3COOH electrolytes showed acceptable performance and oxygen sensing properties. The Bi anodes fabricated by separate manufacturing methods demonstrated effectiveness for use in medical oxygen sensors. Gold thin films were prepared by magnetron sputtering on Flouroethylene Polymer (FEP) films. The FEP substrate temperature ranged from -77°C to 50°C. X-Ray Diffraction (XRD) and 4-point resistivity characterized the effects of substrate temperature to Au thin film particle size. XRD peak broadening and resistivity measurements showed a strong correlation of particle size to FEP substrate temperature. Particle size at 50°C was 594A and the -77°C particle size was 2.4 x 103A. Substrate

  3. Review and outlook: from single nanoparticles to self-assembled monolayers and granular GMR sensors

    Alexander Weddemann

    2010-11-01

    Full Text Available This paper highlights recent advances in synthesis, self-assembly and sensing applications of monodisperse magnetic Co and Co-alloyed nanoparticles. A brief introduction to solution phase synthesis techniques as well as the magnetic properties and aspects of the self-assembly process of nanoparticles will be given with the emphasis placed on selected applications, before recent developments of particles in sensor devices are outlined. Here, the paper focuses on the fabrication of granular magnetoresistive sensors by the employment of particles themselves as sensing layers. The role of interparticle interactions is discussed.

  4. Robust high temperature oxygen sensor electrodes

    Lund, Anders

    Platinum is the most widely used material in high temperature oxygen sensor electrodes. However, platinum is expensive and the platinum electrode may, under certain conditions, suffer from poisoning, which is detrimental for an oxygen sensor. The objective of this thesis is to evaluate electrode...... materials as candidates for robust oxygen sensor electrodes. The present work focuses on characterising the electrochemical properties of a few electrode materials to understand which oxygen electrode processes are limiting for the response time of the sensor electrode. Three types of porous platinum......-Dansensor. The electrochemical properties of the electrodes were characterised by electrochemical impedance spectroscopy (EIS), and the structures were characterised by x-ray diffraction and electron microscopy. At an oxygen partial pressures of 0.2 bar, the response time of the sensor electrode was determined by oxygen...

  5. Limitations of potentiometric oxygen sensors operating at low oxygen levels

    Lund, Anders; Jacobsen, Torben; Hansen, Karin Vels

    2011-01-01

    The electrochemical processes that limit the range of oxygen partial pressures in which potentiometric oxygen sensors can be used, were analysed using a theoretical and an experimental approach. Electrochemical impedance spectroscopy was performed on porous Pt/yttria stabilised zirconia (YSZ......) electrodes between 10−6 and 0.2 bar and at temperatures between 500 and 950 °C. The flow of oxide ions and electron holes through a sensor cell, with a YSZ electrolyte, were calculated under similar conditions. The oxygen permeation of the sensor cell was insignificant at an oxygen partial pressure of 10......−6 bar for an inlet flow rate higher than 2 L h−1 between 600 and 800 °C. The polarisation resistance measured between 10−6 and 10−4 bar was found to be inversely proportional to the oxygen partial pressure, nearly temperature independent and inversely proportional to the inlet gas flow rate, which shows...

  6. Resistive Oxygen Gas Sensors for Harsh Environments

    Moos, Ralf; Izu, Noriya; Rettig, Frank; Reiß, Sebastian; Shin, Woosuck; Matsubara, Ichiro

    2011-01-01

    Resistive oxygen sensors are an inexpensive alternative to the classical potentiometric zirconia oxygen sensor, especially for use in harsh environments and at temperatures of several hundred °C or even higher. This device-oriented paper gives a historical overview on the development of these sensor materials. It focuses especially on approaches to obtain a temperature independent behavior. It is shown that although in the past 40 years there have always been several research groups working concurrently with resistive oxygen sensors, novel ideas continue to emerge today with respect to improvements of the sensor response time, the temperature dependence, the long-term stability or the manufacture of the devices themselves using novel techniques for the sensitive films. Materials that are the focus of this review are metal oxides; especially titania, titanates, and ceria-based formulations. PMID:22163805

  7. Oxygen sensitive polymeric nanocapsules for optical dissolved oxygen sensors

    Sun, Zhijuan; Cai, Chenxin; Guo, Fei; Ye, Changhuai; Luo, Yingwu; Ye, Shuming; Luo, Jianchao; Zhu, Fan; Jiang, Chunyue

    2018-04-01

    Immobilization of the oxygen-sensitive probes (OSPs) in the host matrix greatly impacts the performance and long-term usage of the optical dissolved oxygen (DO) sensors. In this work, fluorescent dyes, as the OSPs, were encapsulated with a crosslinked fluorinated polymer shell by interfacial confined reversible addition fragmentation chain transfer miniemulsion polymerization to fabricate oxygen sensitive polymeric nanocapsules (NCs). The location of fluorescent dyes and the fluorescent properties of the NCs were fully characterized by fourier transform infrared spectrometer, x-ray photoelectron spectrometer and fluorescent spectrum. Dye-encapsulated capacity can be precisely tuned from 0 to 1.3 wt% without self-quenching of the fluorescent dye. The crosslinked fluorinated polymer shell is not only extremely high gas permeability, but also prevents the fluorescent dyes from leakage in aqueous as well as in various organic solvents, such as ethanol, acetone and tetrahydrofuran (THF). An optical DO sensor based on the oxygen sensitive NCs was fabricated, showing high sensitivity, short response time, full reversibility, and long-term operational stability of online monitoring DO. The sensitivity of the optical DO sensor is 7.02 (the ratio of the response value in fully deoxygenated and saturated oxygenated water) in the range 0.96-14.16 mg l-1 and the response time is about 14.3 s. The sensor’s work curve was fit well using the modified Stern-Volmer equation by two-site model, and its response values are hardly affected by pH ranging from 2 to 12 and keep constant during continuous measurement for 3 months. It is believed that the oxygen sensitive polymeric NCs-based optical DO sensor could be particularly useful in long-term online DO monitoring in both aqueous and organic solvent systems.

  8. Bimodular high temperature planar oxygen gas sensor

    Xiangcheng eSun

    2014-08-01

    Full Text Available A bimodular planar O2 sensor was fabricated using NiO nanoparticles (NPs thin film coated yttria-stabilized zirconia (YSZ substrate. The thin film was prepared by radio frequency (r.f. magnetron sputtering of NiO on YSZ substrate, followed by high temperature sintering. The surface morphology of NiO nanoparticles film was characterized by atomic force microscopy (AFM and scanning electron microscopy (SEM. X-ray diffraction (XRD patterns of NiO NPs thin film before and after high temperature O2 sensing demonstrated that the sensing material possesses a good chemical and structure stability. The oxygen detection experiments were performed at 500 °C, 600 °C and 800 °C using the as-prepared bimodular O2 sensor under both potentiometric and resistance modules. For the potentiometric module, a linear relationship between electromotive force (EMF output of the sensor and the logarithm of O2 concentration was observed at each operating temperature, following the Nernst law. For the resistance module, the logarithm of electrical conductivity was proportional to the logarithm of oxygen concentration at each operating temperature, in good agreement with literature report. In addition, this bimodular sensor shows sensitive, reproducible and reversible response to oxygen under both sensing modules. Integration of two sensing modules into one sensor could greatly enrich the information output and would open a new venue in the development of high temperature gas sensors.

  9. Thin film oxygen partial pressure sensor

    Wortman, J. J.; Harrison, J. W.; Honbarrier, H. L.; Yen, J.

    1972-01-01

    The development is described of a laboratory model oxygen partial pressure sensor using a sputtered zinc oxide thin film. The film is operated at about 400 C through the use of a miniature silicon bar. Because of the unique resistance versus temperature relation of the silicon bar, control of the operational temperature is achieved by controlling the resistance. A circuit for accomplishing this is described. The response of sputtered zinc oxide films of various thicknesses to oxygen, nitrogen, argon, carbon dioxide, and water vapor caused a change in the film resistance. Over a large range, film conductance varied approximately as the square root of the oxygen partial pressure. The presence of water vapor in the gas stream caused a shift in the film conductance at a given oxygen partial pressure. A theoretical model is presented to explain the characteristic features of the zinc oxide response to oxygen.

  10. Lifetime of the internal reference oxygen sensor

    Hu, Qiang; Jacobsen, Torben; Hansen, Karin Vels

    2013-01-01

    The internal reference oxygen sensor (IROS) based on a binary mixture of metal and its stoichiometric oxide is subject to leaks that result in consumption of the binary mixture. An IROS loses the functionality when the binary mixture is exhausted. Among the possible leak sources the electronic leak...

  11. Oxygen-Partial-Pressure Sensor for Aircraft Oxygen Mask

    Kelly, Mark; Pettit, Donald

    2003-01-01

    A device that generates an alarm when the partial pressure of oxygen decreases to less than a preset level has been developed to help prevent hypoxia in a pilot or other crewmember of a military or other high-performance aircraft. Loss of oxygen partial pressure can be caused by poor fit of the mask or failure of a hose or other component of an oxygen distribution system. The deleterious physical and mental effects of hypoxia cause the loss of a military aircraft and crew every few years. The device is installed in the crewmember s oxygen mask and is powered via communication wiring already present in all such oxygen masks. The device (see figure) includes an electrochemical sensor, the output potential of which is proportional to the partial pressure of oxygen. The output of the sensor is amplified and fed to the input of a comparator circuit. A reference potential that corresponds to the amplified sensor output at the alarm oxygen-partial-pressure level is fed to the second input of the comparator. When the sensed partial pressure of oxygen falls below the minimum acceptable level, the output of the comparator goes from the low state (a few millivolts) to the high state (near the supply potential, which is typically 6.8 V for microphone power). The switching of the comparator output to the high state triggers a tactile alarm in the form of a vibration in the mask, generated by a small 1.3-Vdc pager motor spinning an eccentric mass at a rate between 8,000 and 10,000 rpm. The sensation of the mask vibrating against the crewmember s nose is very effective at alerting the crewmember, who may already be groggy from hypoxia and is immersed in an environment that is saturated with visual cues and sounds. Indeed, the sensation is one of rudeness, but such rudeness could be what is needed to stimulate the crewmember to take corrective action in a life-threatening situation.

  12. Single nanoparticle tracking spectroscopic microscope

    Yang, Haw [Moraga, CA; Cang, Hu [Berkeley, CA; Xu, Cangshan [Berkeley, CA; Wong, Chung M [San Gabriel, CA

    2011-07-19

    A system that can maintain and track the position of a single nanoparticle in three dimensions for a prolonged period has been disclosed. The system allows for continuously imaging the particle to observe any interactions it may have. The system also enables the acquisition of real-time sequential spectroscopic information from the particle. The apparatus holds great promise in performing single molecule spectroscopy and imaging on a non-stationary target.

  13. Internal-reference solid-electrolyte oxygen sensor

    Haaland, D.M.

    1977-01-01

    A new solid-electrolyte oxygen sensor has been developed that eliminates the conventional oxygen reference in previous solid-electrolyte oxygen sensor designs and is, therefore, ideally suited as an insertion device for remote oxygen monitoring applications. It is constructed with two cells of stabilized zirconia sealed into a small unit using a new high-temperature platinum-zirconia seal. One electrochemical cell monitors the ratio of oxygen partial pressures inside and outside the sensor while the other solid-electrolyte cell is used for quantitative electrochemical pumping of oxygen. The internal oxygen reference is generated by initially pumping all oxygen out of the known internal volume of the sensor and then quantitatively pumping oxygen back in until oxygen partial pressures are equal inside and out. This information is used with the ideal gas law to calculate oxygen partial pressures. Tests were conducted from 400 to 1000 0 C in mixtures of oxygen and nitrogen spanning approximately 0.2 to 21 percent oxygen concentration range. Sensors with sputtered platinum and porous platinum paste electrodes were compared

  14. A fibre optic oxygen sensor for monitoring of human breathing

    Chen, Rongsheng; Farmery, Andrew D.; Chen, Rui; Hahn, Clive E. W.

    2011-11-01

    A reliable and cost effective fibre optic oxygen sensor for monitoring of human breathing has been developed using a normal 200μm silica core/silica cladding optical fibre and a polymer sensing matrix. The fibre optic oxygen sensor is based on the fluorescence quenching of a fluorophore by oxygen. The sensing matrix, containing immobilized Pt(II) complexes, was coated at the end of the silica core/silica cladding optical fibre. The sensitivity and time response of the sensor were evaluated using the method of luminescence lifetime measurement. The polymer substrate influence on the time response of the sensor was improved by using a fibre taper design, and the response time of the optimized sensor was less than 200ms. This silica fibre based optic oxygen sensor is suitable for monitoring of patient breathing in intensive care unit in terms of safety and low cost.

  15. Single Nanoparticle Detection Using Optical Microcavities.

    Zhi, Yanyan; Yu, Xiao-Chong; Gong, Qihuang; Yang, Lan; Xiao, Yun-Feng

    2017-03-01

    Detection of nanoscale objects is highly desirable in various fields such as early-stage disease diagnosis, environmental monitoring and homeland security. Optical microcavity sensors are renowned for ultrahigh sensitivities due to strongly enhanced light-matter interaction. This review focuses on single nanoparticle detection using optical whispering gallery microcavities and photonic crystal microcavities, both of which have been developing rapidly over the past few years. The reactive and dissipative sensing methods, characterized by light-analyte interactions, are explained explicitly. The sensitivity and the detection limit are essentially determined by the cavity properties, and are limited by the various noise sources in the measurements. On the one hand, recent advances include significant sensitivity enhancement using techniques to construct novel microcavity structures with reduced mode volumes, to localize the mode field, or to introduce optical gain. On the other hand, researchers attempt to lower the detection limit by improving the spectral resolution, which can be implemented by suppressing the experimental noises. We also review the methods of achieving a better temporal resolution by employing mode locking techniques or cavity ring up spectroscopy. In conclusion, outlooks on the possible ways to implement microcavity-based sensing devices and potential applications are provided. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. An oxygen pressure sensor using surface acoustic wave devices

    Leighty, Bradley D.; Upchurch, Billy T.; Oglesby, Donald M.

    1993-01-01

    Surface acoustic wave (SAW) piezoelectric devices are finding widespread applications in many arenas, particularly in the area of chemical sensing. We have developed an oxygen pressure sensor based on coating a SAW device with an oxygen binding agent which can be tailored to provide variable sensitivity. The coating is prepared by dissolving an oxygen binding agent in a toluene solution of a copolymer which is then sprayed onto the surface of the SAW device. Experimental data shows the feasibility of tailoring sensors to measure the partial pressure of oxygen from 2.6 to 67 KPa (20 to 500 torr). Potential applications of this technology are discussed.

  17. Precision remote sensor for oxygen and carbon dioxide, Phase I

    National Aeronautics and Space Administration — Mesa Photonics proposes development of a passive optical sensor for simultaneous high-precision measurement of oxygen and carbon dioxide profiles within the full...

  18. A fibre-optic oxygen sensor for monitoring human breathing

    Chen, Rongsheng; Formenti, Federico; Hahn, Clive E W; Farmery, Andrew D; Obeid, Andy

    2013-01-01

    The development and construction of a tapered-tip fibre-optic fluorescence based oxygen sensor is described. The sensor is suitable for fast and real-time monitoring of human breathing. The sensitivity and response time of the oxygen sensor were evaluated in vitro with a gas pressure chamber system, where oxygen partial pressure was rapidly changed between 5 and 15 kPa, and then in vivo in five healthy adult participants who synchronized their breathing to a metronome set at 10, 20, 30, 40, 50, and 60 breaths min –1 . A Datex Ultima medical gas analyser was used to monitor breathing rate as a comparator. The sensor's response time in vitro was less than 150 ms, which allows accurate continuous measurement of inspired and expired oxygen pressure. Measurements of breathing rate by means of our oxygen sensor and of the Datex Ultima were in strong agreement. The results demonstrate that the device can reliably resolve breathing rates up to 60 breaths min –1 , and that it is a suitable cost-effective alternative for monitoring breathing rates and end-tidal oxygen partial pressure in the clinical setting. The rapid response time of the sensor may allow its use for monitoring rapid breathing rates as occur in children and the newborn. (note)

  19. Calibration Of Partial-Pressure-Of-Oxygen Sensors

    Yount, David W.; Heronimus, Kevin

    1995-01-01

    Report and analysis of, and discussion of improvements in, procedure for calibrating partial-pressure-of-oxygen sensors to satisfy Spacelab calibration requirements released. Sensors exhibit fast drift, which results in short calibration period not suitable for Spacelab. By assessing complete process of determining total drift range available, calibration procedure modified to eliminate errors and still satisfy requirements without compromising integrity of system.

  20. Thin film devices used as oxygen partial pressure sensors

    Canady, K. S.; Wortman, J. J.

    1970-01-01

    Electrical conductivity of zinc oxide films to be used in an oxygen partial pressure sensor is measured as a function of temperature, oxygen partial pressure, and other atmospheric constituents. Time response following partial pressure changes is studied as a function of temperature and environmental changes.

  1. Surface acoustic wave oxygen pressure sensor

    Oglesby, Donald M. (Inventor); Upchurch, Billy T. (Inventor); Leighty, Bradley D. (Inventor)

    1994-01-01

    A transducer for the measurement of absolute gas-state oxygen pressure from pressures of less than 100 Pa to atmospheric pressure (1.01 x 10(exp 5) Pa) is based on a standard surface acoustic wave (SAW) device. The piezoelectric material of the SAW device is coated with a compound which will selectively and reversibly bind oxygen. When oxygen is bound by the coating, the mass of the coating increases by an amount equal to the mass of the bound oxygen. Such an increase in the mass of the coating causes a corresponding decrease in the resonant frequency of the SAW device.

  2. Development of oxygen sensors for use in liquid metal

    Van Nieuwenhove, Rudi; Ejenstam, Jesper; Szakalos, Peter

    2015-01-01

    For generation IV reactor concepts, based on liquid metal cooling, there is a need for robust oxygen sensors which can be used in the core of the reactor since corrosion can only be kept sufficiently low by controlling the dissolved oxygen content in the liquid metal. A robust, ceramic membrane type sensor has been developed at IFE/Halden (Norway) and tested in an autoclave system at KTH (Sweden). The sensor has been tested in lead-bismuth at 550 deg. C and performed well. (authors)

  3. Development of oxygen sensors for use in liquid metal

    Van Nieuwenhove, Rudi [Institutt for Energiteknikk, Halden, (Norway); Ejenstam, Jesper; Szakalos, Peter [KTH Royal Institute of Technology, Division of Surface and Corrosion Science, Stockholm, (Sweden)

    2015-07-01

    For generation IV reactor concepts, based on liquid metal cooling, there is a need for robust oxygen sensors which can be used in the core of the reactor since corrosion can only be kept sufficiently low by controlling the dissolved oxygen content in the liquid metal. A robust, ceramic membrane type sensor has been developed at IFE/Halden (Norway) and tested in an autoclave system at KTH (Sweden). The sensor has been tested in lead-bismuth at 550 deg. C and performed well. (authors)

  4. Approaches to single-nanoparticle catalysis.

    Sambur, Justin B; Chen, Peng

    2014-01-01

    Nanoparticles are among the most important industrial catalysts, with applications ranging from chemical manufacturing to energy conversion and storage. Heterogeneity is a general feature among these nanoparticles, with their individual differences in size, shape, and surface sites leading to variable, particle-specific catalytic activity. Assessing the activity of individual nanoparticles, preferably with subparticle resolution, is thus desired and vital to the development of efficient catalysts. It is challenging to measure the activity of single-nanoparticle catalysts, however. Several experimental approaches have been developed to monitor catalysis on single nanoparticles, including electrochemical methods, single-molecule fluorescence microscopy, surface plasmon resonance spectroscopy, X-ray microscopy, and surface-enhanced Raman spectroscopy. This review focuses on these experimental approaches, the associated methods and strategies, and selected applications in studying single-nanoparticle catalysis with chemical selectivity, sensitivity, or subparticle spatial resolution.

  5. Theory and development of fluorescence-based optochemical oxygen sensors: oxygen optodes.

    Opitz, N; Lübbers, D W

    1987-01-01

    As the preceding considerations concerning the physical and technical features of oxygen optodes have demonstrated, fluorescence-based optochemical oxygen sensors possess certain advantages and peculiarities compared to conventionally applied electrochemical sensors such as polarographic oxygen electrodes. First, in contrast to oxygen electrodes, oxygen measurements with oxygen optodes do not suffer from distortions caused by the reference electrodes. In addition, because of the polarographic process, platinum electrodes continuously consume oxygen, which falsifies the results, especially when small sample volumes or long-term measurements, or both, are involved, whereas the sensor layer of oxygen optodes must only be equilibrated. Moreover, the surface of the platinum wire has to be catalytically clean in order to obtain a plateau of the polarogram and, consequently, to achieve a low rest current at zero PO2. Unfortunately, the demand for catalytically clean platinum surfaces turns out to be rather critical, since surface contamination occurs even with membranized electrodes, resulting in the well-known phenomenon of "electrode poisoning." The question of the specificity of oxygen electrodes also must be considered. In this context, CO2 and halothane may interfere with oxygen measurements, whereas fluorescence quenching is unaffected by CO2 and halothane affects the measurements only slightly, depending on the special indicator used. Furthermore, because of the flow dependence, oxygen measurements with the oxygen electrode show a distinct "stirring effect" caused by the turbulence in front of the electrode, which disturbs the diffusion field. Because of the completely different physical principle of fluorescence optical sensors, such influences are not observed with oxygen optodes. In addition, isolation and shielding of electrical circuits found in electrodes are not necessary for optodes. Furthermore, the sensitivity of oxygen optodes can be tuned to the desired

  6. Oxygen partial pressure sensor for gases

    Barbero, J.A.; Azcona, M.A.; Orce, A.

    1997-01-01

    Precise measurement of very low oxygen partial pressure is important in both laboratories and industries. Particularly in nuclear industry, it is relevant in the different steps of the nuclear fuel fabrication. It is presented an instrument which is handy and of easy construction, suitable for the measurement of oxygen partial pressure of gases, in the range of 10 -6 -1 atm. It is based on a solid electrolyte galvanic cell, using Yttria doped zirconia as a ceramic membrane. Through an indirect measurement and calibration, the instrument can be used to measure the content of free oxygen in liquids. It is a import feature in NPP instrumentation. The equipment was calibrated with mixtures of special nonreactive gases. (author). 5 refs

  7. Oxygen partial pressure sensor for gases

    Barbero, J.A.; Azcona, M.A.; Orce, A. [Comision Nacional de Energia Atomica, San Carlos de Bariloche (Argentina). Centro Atomico Bariloche

    1997-10-01

    Precise measurement of very low oxygen partial pressure is important in both laboratories and industries. Particularly in nuclear industry, it is relevant in the different steps of the nuclear fuel fabrication. It is presented an instrument which is handy and of easy construction, suitable for the measurement of oxygen partial pressure of gases, in the range of 10{sup -6}-1 atm. It is based on a solid electrolyte galvanic cell, using Yttria doped zirconia as a ceramic membrane. Through an indirect measurement and calibration, the instrument can be used to measure the content of free oxygen in liquids. It is a import feature in NPP instrumentation. The equipment was calibrated with mixtures of special nonreactive gases. (author). 5 refs.

  8. Biomedical sensor for transcutaneous oxygen measurements using thick film technology

    Lam, Yu-Zhi (Liza)

    2003-01-01

    The measurement of the partial pressure of oxygen in arterial blood is essential for the analysis of a patient's respiratory condition. There are several commercially available methods and systems to measure this parameter transcutaneously. However, they tend to be cumbersome and costly. To overcome the disadvantages presented, a new type of sensor for transcutaneous blood gas measurement was investigated, employing thick film technology, which is an excellent technique to produce sensors in ...

  9. An electrochemical sensor for monitoring oxygen or hydrogen in water

    Leitai Yang; Morris, D.R.; Lister, D.H.

    1997-01-01

    Preliminary studies have been done on a simple electrochemical sensor which shows promise as a cheap, robust instrument for measuring dissolved oxygen or hydrogen in water. The sensor is based upon the solid-state electrolyte ''Nafion'' (trade name of perfluorinated sulphonic acid, manufactured by DuPont Inc.). The Nafion was dissolved in a mixture of aliphatic alcohols, made into a slurry with platinum black, and applied to a ∼1 cm-square electrode made of stainless steel gauze. The potential of the electrode was measured relative to a standard calomel electrode (SCE) in acid solutions at room temperature through which mixtures of oxygen and nitrogen or hydrogen and nitrogen were bubbled. The sensor was responsive to the equilibrating gas with good reproducibility. A similar sensor without the Nafion was not at all sensitive to changes in oxygen concentration. The voltage response of the sensor showed non-Nernstian behaviour, which suggests that the electrochemical reactions at the electrode surface are complex. Further testing of the sensor is required to verify its sensitivity and responsiveness in typical reactor coolant chemistries and to demonstrate its durability over a range of temperatures. (author). 4 refs, 4 figs, 1 tab

  10. An electrochemical sensor for monitoring oxygen or hydrogen in water

    Yang, Leitai; Morris, D R; Lister, D H [University of New Brunswick, Fredericton (Canada). Dept. of Chemical Engineering

    1997-02-01

    Preliminary studies have been done on a simple electrochemical sensor which shows promise as a cheap, robust instrument for measuring dissolved oxygen or hydrogen in water. The sensor is based upon the solid-state electrolyte ``Nafion`` (trade name of perfluorinated sulphonic acid, manufactured by DuPont Inc.). The Nafion was dissolved in a mixture of aliphatic alcohols, made into a slurry with platinum black, and applied to a {approx}1 cm-square electrode made of stainless steel gauze. The potential of the electrode was measured relative to a standard calomel electrode (SCE) in acid solutions at room temperature through which mixtures of oxygen and nitrogen or hydrogen and nitrogen were bubbled. The sensor was responsive to the equilibrating gas with good reproducibility. A similar sensor without the Nafion was not at all sensitive to changes in oxygen concentration. The voltage response of the sensor showed non-Nernstian behaviour, which suggests that the electrochemical reactions at the electrode surface are complex. Further testing of the sensor is required to verify its sensitivity and responsiveness in typical reactor coolant chemistries and to demonstrate its durability over a range of temperatures. (author). 4 refs, 4 figs, 1 tab.

  11. Dissolved hydrogen and oxygen sensors using semiconductor devices

    Hara, Nobuyoshi; Sugimoto, Katsuhisa

    1995-01-01

    The concentrations of DH and DO in aqueous solution are the factors that determine the equilibrium potential of hydrogen and oxygen electrode reactions, respectively, and are the quantities which directly related to the rates of hydrogen generation type and oxygen consumption type corrosion reactions, therefore, they have the important meaning in the electrochemistry of corrosion. In the hydrogen injection into BWR cooling water, the concentration of hydrogen must be controlled strictly, accordingly DH and DO sensors and electrochemical potential sensors are required. For the chemical sensors used in reactor cooling water, the perfectly solid state sensors made of high corrosion resistance materials, which are small size and withstand high temperature and high pressure, must be developed. The structure and the characteristics of the semiconductor devices used as gas sensors, and the principles of DH and DO sensors are described. If the idea of porous or discontinuous membrane gate is developed, the ion sensor of solid structure with one-body reference electrode may be made. (K.I.)

  12. Retrievable micro-inserts containing oxygen sensors for monitoring tissue oxygenation using EPR oximetry

    Dinguizli, M; Beghein, N; Gallez, B

    2008-01-01

    Tissue oxygenation is a crucial parameter in various physiopathological situations and can influence the therapeutic response of tumours. EPR oximetry is a reliable method for assessing and monitoring oxygen levels in vivo over long periods of time. Among the different paramagnetic oxygen sensors available for EPR oximetry, lithium phthalocyanine (LiPc) is a serious candidate for in vivo applications because of its narrow linewidth and its high signal-to-noise ratio. To enhance the biocompatibility of the sensors, fluoropolymer Teflon AF2400 was used to make cylindrical micro-inserts containing LiPc crystals. This new micro-pellet design has several advantages for in vivo studies, including the possibility of being able to choose the implant size, a high sensor content, the facility of in vivo insertion and complete protection with preservation of the oxygen sensor's characteristics. The response to oxygen and the kinetics of this response were tested using in vivo EPR: no differences were observed between micro-inserts and uncoated LiPc crystals. Pellets implanted in vivo in muscles conserved their responsiveness over a long period of time (∼two months), which is much longer than the few days of stability observed using LiPc crystals without protection by the implant. Finally, evaluation of the biocompatibility of the implants revealed no inflammatory reaction around the implantation area

  13. Development of oxygen sensing technology in an irradiated fuel rod. Characteristic test of oxygen sensor

    Saito, Junichi; Hoshiya, Taiji; Sakurai, Fumio; Sakai, Haruyuki

    1996-03-01

    At the Department of JMTR (Japan Materials Test Reactor), the re-instrumentation technologies to a high burnup fuel rod irradiated in an LWR have been developed to study irradiation behavior of the fuel during power transient. It has been progressed developing a chemical sensor as one of the re-instrumentation technologies. This report summarizes the results of characteristic tests of an oxygen sensor made of Yttria Stabilized Zirconia (YSZ) as a solid electrolyte. Several kinds of experiments were carried out to evaluate the electromotive force (emf) performance, stability and lifetime of the oxygen sensor with Ni/NiO, Cr/Cr 2 O 3 and Fe/FeO, respectively as a reference electrode. From the experimental data, it is suggested that the reference electrode of Ni/NiO reveals the most appropriate characteristic of the sensor to measure the partial oxygen pressure in a fuel rod. It is the final goal of this development to clarify the change of oxygen chemical potential in a fuel rod during power transient. (author)

  14. Improved Internal Reference Oxygen Sensors with Composite Ceramic Electrodes

    Hu, Qiang; Jacobsen, Torben; Hansen, Karin Vels

    2012-01-01

    Potentiometric oxygen sensors with an internal reference electrode, which uses the equilibrium pO2 of the binary mixture of Ni/NiO as the reference, are demonstrated. The cells employ Pt or composite ceramics as the sensing electrode. The cells are fabricated by a flexible and potentially low cost...... and performance are highly reproducible. The composite ceramics, based on strontium doped manganite and yttria doped zirconia, are proven superior over Pt to serve as the electrode material....

  15. Contact CMOS imaging of gaseous oxygen sensor array.

    Daivasagaya, Daisy S; Yao, Lei; Yi Yung, Ka; Hajj-Hassan, Mohamad; Cheung, Maurice C; Chodavarapu, Vamsy P; Bright, Frank V

    2011-10-01

    We describe a compact luminescent gaseous oxygen (O 2 ) sensor microsystem based on the direct integration of sensor elements with a polymeric optical filter and placed on a low power complementary metal-oxide semiconductor (CMOS) imager integrated circuit (IC). The sensor operates on the measurement of excited-state emission intensity of O 2 -sensitive luminophore molecules tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) ([Ru(dpp) 3 ] 2+ ) encapsulated within sol-gel derived xerogel thin films. The polymeric optical filter is made with polydimethylsiloxane (PDMS) that is mixed with a dye (Sudan-II). The PDMS membrane surface is molded to incorporate arrays of trapezoidal microstructures that serve to focus the optical sensor signals on to the imager pixels. The molded PDMS membrane is then attached with the PDMS color filter. The xerogel sensor arrays are contact printed on top of the PDMS trapezoidal lens-like microstructures. The CMOS imager uses a 32 × 32 (1024 elements) array of active pixel sensors and each pixel includes a high-gain phototransistor to convert the detected optical signals into electrical currents. Correlated double sampling circuit, pixel address, digital control and signal integration circuits are also implemented on-chip. The CMOS imager data is read out as a serial coded signal. The CMOS imager consumes a static power of 320 µW and an average dynamic power of 625 µW when operating at 100 Hz sampling frequency and 1.8 V DC. This CMOS sensor system provides a useful platform for the development of miniaturized optical chemical gas sensors.

  16. Improved Internal Reference Oxygen Sensors Using Composite Oxides as Electrodes

    Hu, Qiang

    The thesis describes the research on and development of an internal reference oxygen sensor (IROS). The IROS is potentiometric and uses the equilibrium pO2of the binary mixture of Ni/NiO as the reference pO2. The sensing electrode of the IROS are made from metallic Pt or the composite of (La0.75S...... the application of IROSes are provided. Based on the concepts and fundamentals of the IROS, internal reference sensors that detect other gas species such as hydrogen, chlorine and bromine may be developed.......The thesis describes the research on and development of an internal reference oxygen sensor (IROS). The IROS is potentiometric and uses the equilibrium pO2of the binary mixture of Ni/NiO as the reference pO2. The sensing electrode of the IROS are made from metallic Pt or the composite of (La0.75Sr0...... from 8YSZ is evaluated quantitatively and figures that may be used to design the depletion period of an IROS due to the electronic leak of 8YSZ are provided. One dimensional numerical simulations are performed to study the variation in cell voltage during the process of gas mixing, and the asymmetric...

  17. About Error in Measuring Oxygen Concentration by Solid-Electrolyte Sensors

    V. I. Nazarov

    2008-01-01

    Full Text Available The paper evaluates additional errors while measuring oxygen concentration in a gas mixture by a solid-electrolyte cell. Experimental dependences of additional errors caused by changes in temperature in a sensor zone, discharge of gas mixture supplied to a sensor zone, partial pressure in the gas mixture and fluctuations in oxygen concentrations in the air.

  18. Online analysis of oxygen inside silicon-glass microreactors with integrated optical sensors

    Ehgartner, Josef; Sulzer, Philipp; Burger, Tobias

    2016-01-01

    A powerful online analysis set-up for oxygen measurements within microfluidic devices is presented. It features integration of optical oxygen sensors into microreactors, which enables contactless, accurate and inexpensive readout using commercially available oxygen meters via luminescent lifetime...... monitoring of enzyme transformations, including d-alanine or d-phenylalanine oxidation by d-amino acid oxidase, and glucose oxidation by glucose oxidase....

  19. Oxygen sensor development and low temperature corrosion study in lead-alloy coolant loop

    Hwang, Il Soon; Bahn, Chi Bum; Lee, Seung Gi; Jeong, Seung Ho; Nam, Hyo On; Lim, Jun

    2007-07-01

    Oxygen sensor to measure dissolved oxygen concentration at liquid lead-bismuth eutectic environments have been developed. Developed oxygen sensor for application in lead-bismuth eutectic (LBE) system was based on the oxygen ion conductor made of YSZ ceramic having Bi/Bi2O3 reference joined by electro-magnetic swaging. Leakage problem, which was major problem of existing sensors, can be solved by using electro-magnetic swaging method. A new calibration strategy combining the oxygen titration with electrochemical impedance spectroscopy (EIS) was performed to increase the reliability of sensor. Another calibration was also conducted by controlling the oxygen concentration using OCS (oxygen control system). Materials corrosion tests of various metals (SS316, EP823, T91 and HT9) were conducted for up to 1,000 hours with specimen inspection after every 333hours at 450 .deg. C in HELIOS. Oxygen concentration was controlled at 10 -6 wt% by using the direct gas bubbling of Ar+4%H 2 , Ar+5%O 2 and pure Ar. The dissolved oxygen concentration in LBE was also monitored by two calibrated YSZ oxygen sensors located at different places under different temperatures within HELIOS. It shows a good performance during 1000 hours. Liquid metal embrittlement (LME) test of SS316L specimen in the LBE was performed at various temperature and strain rate. The result shows that the liquid metal embrittlement effect is not crucial at tested conditions

  20. Oxygen sensors for Heavy Liquid Metal coolants: Calibration and assessment of the minimum reading temperature

    Bassini, S., E-mail: serena.bassini@enea.it; Antonelli, A.; Di Piazza, I.; Tarantino, M.

    2017-04-01

    Oxygen sensors for Heavy Liquid Metals (HLMs) such as lead and LBE (lead-bismuth eutectic) will be essential devices in future Lead Fast Reactor (LFR) and Accelerator Driven System (ADS). Potentiometric sensors based on solid electrolytes were developed in recent years to this purpose. Internal reference electrodes such as Pt-air and Bi/Bi{sub 2}O{sub 3} liquid metal/metal-oxide are among the most used but they both have a weak point: Pt-air sensor has a high minimum reading temperature around 400 °C whereas Bi/Bi{sub 2}O{sub 3} suffers from internal stresses induced by Bi volume variations with temperature, which may lead to the sensor failure in the long-term. The present work describes the performance of standard Pt-air and Bi/Bi{sub 2}O{sub 3} sensors and compares them with recent Cu/Cu{sub 2}O sensor. Sensors with Yttria Partially Stabilized Zirconia (YPSZ) electrolyte were calibrated in oxygen-saturated HLM between 160 and 550 °C and the electric potential compared to the theoretical one to define the accuracy and the minimum reading temperature. Standard Pt-air sensor were also tested using Yttria Totally Stabilized Zirconia (YTSZ) to assess the effect of a different electrolyte on the minimum reading temperature. The performance of Pt-air and Cu/Cu{sub 2}O sensors with YPSZ electrolyte were then tested together in low-oxygen HLM between 200 and 450 °C. The results showed that Pt-air, Bi/Bi{sub 2}O{sub 3} and Cu/Cu{sub 2}O sensors with YPSZ measured oxygen in HLMs down to 400 °C, 290 °C and 200 °C respectively. When the YTSZ electrolyte was used in place of the YPSZ, the Pt-air sensor measured correctly down to at least 350 °C thanks to the superior ionic conductivity of the YTSZ. When Cu/Cu{sub 2}O and Pt-air sensors were tested together in the same low-oxygen HLM between 200 and 450 °C, Cu/Cu{sub 2}O sensor worked predictably in the whole temperature range whereas Pt-air sensor exhibited a correct output only above 400 °C. - Highlights: •Oxygen

  1. Characterization and re-activation of oxygen sensors for use in liquid lead-bismuth

    Kurata, Yuji; Abe, Yuji; Futakawa, Masatoshi; Oigawa, Hiroyuki

    2010-01-01

    Control of oxygen concentration in liquid lead-bismuth is one of the most important tasks to develop accelerator driven systems. In order to improve the reliability of oxygen sensors, re-activation treatments were investigated as well as characterization of oxygen sensors for use in liquid lead-bismuth. The oxygen sensor with a solid electrolyte of yttria-stabilized zirconia and a Pt/gas reference electrode showed almost the same electromotive force values in gas and liquid lead-bismuth, respectively, as the theoretical ones at temperatures above 400 deg. C or 450 deg. C. After long-term use of 6500 h, the outputs of the sensor became incorrect in liquid lead-bismuth. The state of the sensor that indicated incorrect outputs could not be recovered by cleaning with a nitric acid. However, it was found that the oxygen sensor became a correct sensor indicating theoretical values in liquid lead-bismuth after re-activation by the Pt-treatment of the outer surface of the sensor.

  2. Investigations of a zirconia solid electrolyte oxygen sensor in liquid lead

    Rivai, Abu Khalid, E-mail: rivai.abukhalid@jaea.go.j [Department of Nuclear Engineering, Graduate School of Science and Engineering, Tokyo Institute of Technology, N1-18, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8550 (Japan); Takahashi, Minoru, E-mail: mtakahas@nr.titech.ac.j [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, N1-18, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8550 (Japan)

    2010-03-15

    Investigations of a magnesia-stabilized zirconia solid electrolyte oxygen sensor for oxygen control measurement in liquid lead were carried out. The fluid of Bi/Bi{sub 2}O{sub 3} as a reference electrode and a molybdenum wire as a working electrode to detect the output signal of the sensor were used. The Nernst equation was used to estimate the electromotive force (EMF) values theoretically. The temperatures of liquid lead were 500, 550 and 600 deg. C. The results showed that the injection gas temperatures did not affect the detected EMF, the sensor responded well to quick changes of oxygen activity in liquid lead, and the discrepancy between the measured and theoretical EMF of the oxygen sensor output signal was higher at 500 deg. C than at 550 and 600 deg. C.

  3. Optical Sensors for Hydrogen and Oxygen for Unambiguous Detection in Their Mutual Presence, Phase I

    National Aeronautics and Space Administration — The objective of the Phase I SBIR project is to develop sensors that can discriminate the presence of combustible gases like oxygen (O2) in hydrogen (H2) or H2 in O2...

  4. Oxygen optodes as fast sensors for eddy correlation measurements in aquatic systems

    Chipman, Lindsay; Huettel, Markus; Berg, Peter

    2012-01-01

    The aquatic eddy-correlation technique can be used to noninvasively determine the oxygen exchange across the sediment-water interface by analyzing the covariance of vertical flow velocity and oxygen concentration in a small measuring volume above the sea bed. The method requires fast sensors...... that combine the advantages of noninvasive measurements and integration of fluxes over a large footprint area, using a relatively rugged and less expensive sensor....

  5. Sensors

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

    1999-10-01

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

  6. Effect of Humid Aging on the Oxygen Adsorption in SnO₂ Gas Sensors.

    Suematsu, Koichi; Ma, Nan; Watanabe, Ken; Yuasa, Masayoshi; Kida, Tetsuya; Shimanoe, Kengo

    2018-01-16

    To investigate the effect of aging at 580 °C in wet air (humid aging) on the oxygen adsorption on the surface of SnO₂ particles, the electric properties and the sensor response to hydrogen in dry and humid atmospheres for SnO₂ resistive-type gas sensors were evaluated. The electric resistance in dry and wet atmospheres at 350 °C was strongly increased by humid aging. From the results of oxygen partial pressure dependence of the electric resistance, the oxygen adsorption equilibrium constants ( K ₁; for O - adsorption, K ₂; for O 2- adsorption) were estimated on the basis of the theoretical model of oxygen adsorption. The K ₁ and K ₂ in dry and wet atmospheres at 350 °C were increased by humid aging at 580 °C, indicating an increase in the adsorption amount of both O - and O 2- . These results suggest that hydroxyl poisoning on the oxygen adsorption is suppressed by humid aging. The sensor response to hydrogen in dry and wet atmosphere at 350 °C was clearly improved by humid aging. Such an improvement of the sensor response seems to be caused by increasing the oxygen adsorption amount. Thus, the humid aging offers an effective way to improve the sensor response of SnO₂ resistive-type gas sensors in dry and wet atmospheres.

  7. Effect of Humid Aging on the Oxygen Adsorption in SnO2 Gas Sensors

    Koichi Suematsu

    2018-01-01

    Full Text Available To investigate the effect of aging at 580 °C in wet air (humid aging on the oxygen adsorption on the surface of SnO2 particles, the electric properties and the sensor response to hydrogen in dry and humid atmospheres for SnO2 resistive-type gas sensors were evaluated. The electric resistance in dry and wet atmospheres at 350 °C was strongly increased by humid aging. From the results of oxygen partial pressure dependence of the electric resistance, the oxygen adsorption equilibrium constants (K1; for O− adsorption, K2; for O2− adsorption were estimated on the basis of the theoretical model of oxygen adsorption. The K1 and K2 in dry and wet atmospheres at 350 °C were increased by humid aging at 580 °C, indicating an increase in the adsorption amount of both O− and O2−. These results suggest that hydroxyl poisoning on the oxygen adsorption is suppressed by humid aging. The sensor response to hydrogen in dry and wet atmosphere at 350 °C was clearly improved by humid aging. Such an improvement of the sensor response seems to be caused by increasing the oxygen adsorption amount. Thus, the humid aging offers an effective way to improve the sensor response of SnO2 resistive-type gas sensors in dry and wet atmospheres.

  8. Calibration and testing of a polarographic sensor for the measurement of oxygen in seawater

    Boniforti, R; Dell' Amico, F; Marri, P

    1987-04-01

    The procedures for the calibration and testing of a polarographic oxygen sensor, mounted on a CTD probe, are reported. As an example of in-field use, oxygen and temperature profiles obtained in Fossa del Pomo (Central Adriatic Sea), are given.

  9. Singlet Oxygen Sensor Green: Photochemical Behavior in Solution and in a Mammalian Cell

    Gollmer, Anita; Arnbjerg, Jacob; Blaikie, Frances Helen

    2011-01-01

    The development of efficient and selective luminescent probes for reactive oxygen species, particularly for singlet molecular oxygen, is currently of great importance. In this study, the photochemical behavior of Singlet Oxygen Sensor Green® (SOSG), a commercially available fluorescent probe...... of the reaction between SOSG and singlet oxygen is, itself, an efficient singlet oxygen photosensitizer. Second, SOSG appears to efficiently bind to proteins which, in turn, can influence uptake by a cell as well as behavior in the cell. As such, incorrect use of SOSG can yield misleading data on yields...

  10. Development status of oxygen solid electrolyte sensors in HLMC in respect to monoblock reactor facilities

    Martynov, P.N.; Askhadullin, R.Sh.; Storozhenko, A.N.; Shelemet'ev, V.M.; Sadovnichij, R.P.; Ivanov, I.I.

    2014-01-01

    The results of developing sensors on the base of solid electrolytes to control oxygen in lead and lead-bismuth coolants are considered. It is found out that ceramic detecting elements on the base of solid electrolytes from oxide ceramics are able to work a long time in conditions of high temperatures and thermal shocks in molten metals (in gases). They show stable conducting and mechanical properties, thermal resistance, low gas permeability. Using considered detecting elements different sensors, including ones for monoblock reactors and facilities, are developed and manufactured. The given sensors can be used for both continuous and periodical oxygen control in heavy liquid metal coolants [ru

  11. A new immersion sensor for rapid electrochemical determination of dissolved oxygen in liquid metals

    Janke, D.; Schwerdtfeger, K.

    1978-01-01

    Development of a new solid electrolyte 'needle sensor' with ZrO 2 or ThO 2 electrolyte and metal-metal oxide reference mixture for the rapid determination of oxygen in steel melts. Details of the manufacture of the layer-structured, miniaturized probe. Test results of simultaneous measurements performed with the newly developed ZrO 2 needle sensor and the hitherto usual tubular sensor in iron melts at oxygen activities between 0.00005 and 0.030. (orig.) [de

  12. Oxygen Optode Sensors: Principle, Characterization, Calibration, and Application in the Ocean

    Henry C. Bittig

    2018-01-01

    Full Text Available Recently, measurements of oxygen concentration in the ocean—one of the most classical parameters in chemical oceanography—are experiencing a revival. This is not surprising, given the key role of oxygen for assessing the status of the marine carbon cycle and feeling the pulse of the biological pump. The revival, however, has to a large extent been driven by the availability of robust optical oxygen sensors and their painstakingly thorough characterization. For autonomous observations, oxygen optodes are the sensors of choice: They are used abundantly on Biogeochemical-Argo floats, gliders and other autonomous oceanographic observation platforms. Still, data quality and accuracy are often suboptimal, in some part because sensor and data treatment are not always straightforward and/or sensor characteristics are not adequately taken into account. Here, we want to summarize the current knowledge about oxygen optodes, their working principle as well as their behavior with respect to oxygen, temperature, hydrostatic pressure, and response time. The focus will lie on the most widely used and accepted optodes made by Aanderaa and Sea-Bird. We revisit the essentials and caveats of in-situ in air calibration as well as of time response correction for profiling applications, and provide requirements for a successful field deployment. In addition, all required steps to post-correct oxygen optode data will be discussed. We hope this summary will serve as a comprehensive, yet concise reference to help people get started with oxygen observations, ensure successful sensor deployments and acquisition of highest quality data, and facilitate post-treatment of oxygen data. In the end, we hope that this will lead to more and higher-quality oxygen observations and help to advance our understanding of ocean biogeochemistry in a changing ocean.

  13. A plastic optical fiber sensor for the dual sensing of temperature and oxygen

    Lo, Yu-Lung; Chu, Chen-Shane

    2008-04-01

    This study presents a low-cost plastic optical fiber sensor for the dual sensing of temperature and oxygen. The sensor features a commercially available epoxy glue coated on the side-polished fiber surface for temperature sensing and a fluorinated xerogel doped with platinum tetrakis pentrafluoropheny porphine (PtTFPP) coated on the fiber end for oxygen sensing. The temperature and oxygen indicators are both excited using a UV LED light source with a wavelength of 380 nm. The luminescence emission spectra of the two indicators are well resolved and exhibit no cross-talk effects. Overall, the results indicate that the dual sensor presented in this study provides an ideal solution for the non-contact, simultaneous sensing of temperature and oxygen in general biological and medical applications.

  14. Effects of palladium coatings on oxygen sensors of titanium dioxide thin films

    Castaneda, L.

    2007-01-01

    Titanium dioxide (TiO 2 -anatase phase) thin films were deposited by the ultrasonic spray pyrolysis technique employing titanium (IV) oxide acetylacetonate (TiO(acac) 2 ) dissolved in pure methanol as a source material. In order to prepare oxygen sensors, TiO 2 thin films were deposited on interdigitated gold electrodes with contacted alumina substrates. Palladium (Pd) coatings were carried out by vacuum thermal evaporation through a metallic mask. The effect of the surface additive (Pd) on the response of the thin film TiO 2 oxygen sensors was monitored in a mixture with zero-grade air. The electrical characterization (monitoring of the electrical surface resistance with the operation temperature) of the sensors in an atmosphere of oxygen (diluted in zero-grade air) was performed in a vacuum chamber (10 -6 Torr), where the gas pressure can be controlled. The films sensitivity was estimated by the following relation: s=R gas -R 0 /R 0 . The response time of the sensor is defined to be the time needed to reach a 0.9R 0 value when the oxygen excess is removed. The gas-sensing properties of TiO 2 sensors in an atmosphere of 10 4 ppm of oxygen were measured between 100 and 450 deg. C. Experimental results obtained using palladium as a surface additive show that the sensitivity reaches a stationary value of 1.18 for O 2 concentration of 100ppm in zero-grade air at 300 deg. C, which is as high as those reported for oxygen sensors prepared with more expensive and complex techniques. The role and activity of palladium coatings incorporated on solid-state oxygen sensors are determined by their chemical state, aggregation form and interaction with the metal-oxide semiconductor

  15. Pericellular oxygen monitoring with integrated sensor chips for reproducible cell culture experiments.

    Kieninger, J; Aravindalochanan, K; Sandvik, J A; Pettersen, E O; Urban, G A

    2014-04-01

    Here we present an application, in two tumour cell lines, based on the Sensing Cell Culture Flask system as a cell culture monitoring tool for pericellular oxygen sensing. T-47D (human breast cancer) and T98G (human brain cancer) cells were cultured either in atmospheric air or in a glove-box set at 4% oxygen, in both cases with 5% CO2 in the gas phase. Pericellular oxygen tension was measured with the help of an integrated sensor chip comprising oxygen sensor arrays. Obtained results illustrate variation of pericellular oxygen tension in attached cells covered by stagnant medium. Independent of incubation conditions, low pericellular oxygen concentration levels, usually associated with hypoxia, were found in dense cell cultures. Respiration alone brought pericellular oxygen concentration down to levels which could activate hypoxia-sensing regulatory processes in cultures believed to be aerobic. Cells in culture believed to experience conditions of mild hypoxia may, in reality, experience severe hypoxia. This would lead to incorrect assumptions and suggests that pericellular oxygen concentration readings are of great importance to obtain reproducible results when dealing with hypoxic and normoxic (aerobic) incubation conditions. The Sensing Cell Culture Flask system allows continuous monitoring of pericellular oxygen concentration with outstanding long-term stability and no need for recalibration during cell culture experiments. The sensor is integrated into the flask bottom, thus in direct contact with attached cells. No additional equipment needs to be inserted into the flask during culturing. Transparency of the electrochemical sensor chip allows optical inspection of cells attached on top of the sensor. © 2014 John Wiley & Sons Ltd.

  16. Development of sensors for monitoring oxygen and free radicals in plant physiology

    Chaturvedi, Prachee

    Oxygen plays a critical role in the physiology of photosynthetic organisms, including bioenergetics, metabolism, development, and stress response. Oxygen levels affect photosynthesis, respiration, and alternative oxidase pathways. Likewise, the metabolic rate of spatially distinct plant cells (and therefore oxygen flux) is known to be affected by biotic stress (e.g., herbivory) and environmental stress (e.g., salt/nutrient stress). During aerobic metabolism, cells produce reactive oxygen species (ROS) as a by product. Plants also produce ROS during adaptation to stress (e.g., abscisic acid (ABA) mediated stress responses). If stress conditions are prolonged, ROS levels surpass the capacity of detoxifying mechanisms within the cell, resulting in oxidative damage. While stress response pathways such as ABA-mediated mechanisms have been well characterized (e.g., water stress, inhibited shoot growth, synthesis of storage proteins in seeds), the connection between ROS production, oxygen metabolism and stress response remains unknown. In part, this is because details of oxygen transport at the interface of cell(s) and the surrounding microenvironment remains nebulous. The overall goal of this research was to develop oxygen and Free radical sensors for studying stress signaling in plants. Recent developments in nanomaterials and data acquisition systems were integrated to develop real-time, non-invasive oxygen and Free radical sensors. The availability of these sensors for plant physiologists is an exciting opportunity to probe the functional realm of cells and tissues in ways that were not previously possible.

  17. A miniaturized oxygen sensor integrated on fiber surface based on evanescent-wave induced fluorescence quenching

    Xiong, Yan [School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500 (China); Oil and Gas Field Applied Chemistry Key Laboratory of Sichuan Province, Southwest Petroleum University, Chengdu, 610500 (China); Tan, Jun; Wang, Chengjie; Zhu, Ying [School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500 (China); Fang, Shenwen [School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500 (China); Oil and Gas Field Applied Chemistry Key Laboratory of Sichuan Province, Southwest Petroleum University, Chengdu, 610500 (China); Wu, Jiayi; Wang, Qing [School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500 (China); Duan, Ming, E-mail: swpua124@126.com [State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500 (China); School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500 (China); Oil and Gas Field Applied Chemistry Key Laboratory of Sichuan Province, Southwest Petroleum University, Chengdu, 610500 (China)

    2016-11-15

    In this work, a miniaturized sensor was integrated on fiber surface and developed for oxygen determination through evanescent-wave induced fluorescence quenching. The sensor was designed by using light emitting diode (LED) as light source and optical fiber as light transmission element. Tris(2,2′-bipyridyl) ruthenium ([Ru(bpy){sub 3}]{sup 2+}) fluorophore was immobilized in the organically modified silicates (ORMOSILs) film and coated onto the fiber surface. When light propagated by total internal reflection (TIR) in the fiber core, evanescent wave could be produced on the fiber surface and excite [Ru(bpy){sub 3}]{sup 2+} fluorophore to produce fluorescence emission. Then oxygen could be determinated by its quenching effect on the fluorescence and its concentration could be evaluated according to Stern–Volumer model. Through integrating evanescent wave excitation and fluorescence quenching on fiber surface, the sensor was successfully miniaturized and exhibit improved performances of high sensitivity (1.4), excellent repeatability (1.2%) and fast analysis (12 s) for oxygen determination. The sensor provided a newly portable method for in-situ and real-time measurement of oxygen and showed potential for practical oxygen analysis in different application fields. Furthermore, the fabrication of this sensor provides a miniaturized and portable detection platform for species monitoring by simple modular design. - Highlights: • ORMOSILs sensing film immobilized with [Ru(bpy){sub 3}]{sup 2+} fluorophore was coated on fiber surface. • Evanescent wave on the fiber surface was utilized as excitation source to produce fluorescence. • Oxygen was measured based on its quenching effect on evanescent wave-induce fluorescence. • Sensor fabrication was miniaturized by integrating detection and sensing elements on the fiber. • The modular design sensor provides a detection platform for other species monitoring.

  18. Performance of solid electrolyte type oxygen sensor in flowing lead bismuth

    Kondo, Masatoshi; Takahashi, Minoru

    2005-01-01

    A solid electrolyte type oxygen sensor for liquid 45%lead-55%bismuth (Pb-Bi) was developed. The performance of the oxygen sensor in the flowing lead-bismuth (Pb-Bi) was investigated. The initial performance of the sensor was not reliable, since the reference fluid of the oxygen saturated bismuth in the sensor cell was not compact initially. The electromotive force (EMF) obtained from the yttria stabilized zirconia (YSZ) cell was the same as that from the magnesia stabilized zirconia (MSZ) cell in the flowing Pb-Bi. The EMF of the sensor in the flowing Pb-Bi was lower than that in the stagnant Pb-Bi. However, the difference was small. The sensor showed repeatability after the long term interruption and the Pb-Bi drain/charge operation. After the performance tests, the corrosion of the sensor cells were investigated metallurgically. The YSZ cell was eroded around the free surface of the flowing Pb-Bi after 3500 hour-exposure in the flowing Pb-Bi. The MSZ cell showed smooth surface without the erosion. Although the YSZ cell worked more stably than the MSZ cell, the mechanical strength of the YSZ cell is weaker than that of the MSZ cell. (author)

  19. Inhomogeneous Oxygen Vacancy Distribution in Semiconductor Gas Sensors: Formation, Migration and Determination on Gas Sensing Characteristics

    Jianqiao Liu

    2017-08-01

    Full Text Available The density of oxygen vacancies in semiconductor gas sensors was often assumed to be identical throughout the grain in the numerical discussion of the gas-sensing mechanism of the devices. In contrast, the actual devices had grains with inhomogeneous distribution of oxygen vacancy under non-ideal conditions. This conflict between reality and discussion drove us to study the formation and migration of the oxygen defects in semiconductor grains. A model of the gradient-distributed oxygen vacancy was proposed based on the effects of cooling rate and re-annealing on semiconductive thin films. The model established the diffusion equations of oxygen vacancy according to the defect kinetics of diffusion and exclusion. We described that the steady-state and transient-state oxygen vacancy distributions, which were used to calculate the gas-sensing characteristics of the sensor resistance and response to reducing gases under two different conditions. The gradient-distributed oxygen vacancy model had the applications in simulating the sensor performances, such as the power law, the grain size effect and the effect of depletion layer width.

  20. Inhomogeneous Oxygen Vacancy Distribution in Semiconductor Gas Sensors: Formation, Migration and Determination on Gas Sensing Characteristics.

    Liu, Jianqiao; Gao, Yinglin; Wu, Xu; Jin, Guohua; Zhai, Zhaoxia; Liu, Huan

    2017-08-10

    The density of oxygen vacancies in semiconductor gas sensors was often assumed to be identical throughout the grain in the numerical discussion of the gas-sensing mechanism of the devices. In contrast, the actual devices had grains with inhomogeneous distribution of oxygen vacancy under non-ideal conditions. This conflict between reality and discussion drove us to study the formation and migration of the oxygen defects in semiconductor grains. A model of the gradient-distributed oxygen vacancy was proposed based on the effects of cooling rate and re-annealing on semiconductive thin films. The model established the diffusion equations of oxygen vacancy according to the defect kinetics of diffusion and exclusion. We described that the steady-state and transient-state oxygen vacancy distributions, which were used to calculate the gas-sensing characteristics of the sensor resistance and response to reducing gases under two different conditions. The gradient-distributed oxygen vacancy model had the applications in simulating the sensor performances, such as the power law, the grain size effect and the effect of depletion layer width.

  1. Singlet Oxygen Sensor Green: Photochemical Behavior in Solution and in a Mammalian Cell

    Gollmer, Anita; Arnbjerg, Jacob; Blaikie, Frances Helen

    2011-01-01

    The development of efficient and selective luminescent probes for reactive oxygen species, particularly for singlet molecular oxygen, is currently of great importance. In this study, the photochemical behavior of Singlet Oxygen Sensor Green® (SOSG), a commercially available fluorescent probe...... for singlet oxygen, was examined. Despite published claims to the contrary, the data presented herein indicate that SOSG can, in fact, be incorporated into a living mammalian cell. However, for a number of reasons, caution must be exercised when using SOSG. First, it is shown that the immediate product...... of the reaction between SOSG and singlet oxygen is, itself, an efficient singlet oxygen photosensitizer. Second, SOSG appears to efficiently bind to proteins which, in turn, can influence uptake by a cell as well as behavior in the cell. As such, incorrect use of SOSG can yield misleading data on yields...

  2. Development of oxygen sensors using zirconia solid electrolyte for fuel rods

    Hiura, Nobuo; Endou, Yasuichi; Yamaura, Takayuki; Matui, Yoshinori; Niimi, Motoji; Hoshiya, Taiji; Kobiyama, Mamoru; Motohashi, Yoshinobu

    1999-01-01

    The oxygen potential in oxide fuel pellet is an important parameter to understand behavior of high burn up fuel and its integrity. Zirconia solid electrolyte which is durable under irradiation and high temperature is considered as candidate material for the oxygen potential. Combined use of solid electrolyte and Ni/NiO as a solid standard electrode will realize small size oxygen sensor which can be easily loaded in the fuel rod. Prototypes of the oxygen sensor made of these materials were irradiated with neutrons the Japan Materials Testing Reactor (JMTR), and characteristics of electromotive force (EMF) by sensors were examined under irradiation. For a prototype using zirconia solid electrolyte stabilized by Y 2 O 3 (YSZ), measured EMF under irradiation was nearly equivalent to the value under unirradiated condition, and very stable within a range of neutron fluence (E>1 MeV) up to 1.52 x 10 23 m -2 and for the time of 600 h. However, the measured EMFs were slightly smaller than the theoretical values. The reason for this decrease of the EMF was thought as due to insufficient adhesion forces between solid electrolyte and standard electrode. After modification of the sensor to increase adhesion force, EMF was measured again under irradiation. The results showed improvement of the characteristics of the sensor in which measured EMFs were almost equivalent to the theoretical values. (author)

  3. Low-temperature behavior of ZrO2 oxygen sensors

    Badwal, S.P.S.; Bannister, M.J.

    1983-01-01

    The relative importance of the solid electrolyte and the electrodes in determining the low-temperature behavior of stabilized zirconia oxygen sensors is considered. Contrary to general belief, the electrodes play the more important role at low temperatures. The performance may be greatly improved by using, instead of porous platinum, oxide electrodes comprising solid solutions based on UO 2 . Laboratory tests and plant trials show that ideal behavior in oxygen-excess gases can be achieved below 400 0 C

  4. Enzymatic Sensor of Putrescine with Optical Oxygen Transducer - Mathematical Model of Responses of Sensitive Layer.

    Maixnerová, Lucie; Horvitz, Alexandar; Kuncová, Gabriela; Přibyl, M.; Šebela, M.; Koštejn, Martin

    2015-01-01

    Roč. 69, č. 1 (2015), s. 158-166 ISSN 0366-6352 R&D Projects: GA TA ČR TA03010548; GA MŠk(CZ) LO1204 Institutional support: RVO:67985858 Keywords : enzymatic sensor * putrescine * optical oxygen transducer Subject RIV: CE - Biochemistry Impact factor: 1.326, year: 2015

  5. A comparison of oxygen saturation measurements obtained from a 'blue sensor' with a standard sensor.

    Mawson, Isabel E; Dawson, Jennifer A; Donath, Susan M; Davis, Peter G

    2011-10-01

    The study aims to investigate pulse oximetry measurements from a 'blue' pulse oximeter sensor against measurements from a 'standard' pulse oximeter sensor in newly born infants. Immediately after birth, both sensors were attached to the infant, one to each foot. SpO₂ measurements were recorded simultaneously from each sensor for 10 min. Agreement between pairs of SpO₂ measurements were calculated using Bland-Altman analysis. Thirty-one infants were studied. There was good correlation between simultaneous SpO₂ measurements from both sensors (r² = 0.75). However, the mean difference between 'blue' and 'standard' sensors was -1.6%, with wide 95% limits of agreement +18.4 to -21.6%. The range of mean difference between sensors from each infant ranged from -20 to +20. The mean difference between the blue and standard sensor SpO₂ measurements is not clinically important. © 2011 The Authors. Journal of Paediatrics and Child Health © 2011 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

  6. Fluorophore-based sensor for oxygen radicals in processing plasmas

    Choudhury, Faraz A.; Shohet, J. Leon; Sabat, Grzegorz; Sussman, Michael R.; Nishi, Yoshio

    2015-01-01

    A high concentration of radicals is present in many processing plasmas, which affects the processing conditions and the properties of materials exposed to the plasma. Determining the types and concentrations of free radicals present in the plasma is critical in order to determine their effects on the materials being processed. Current methods for detecting free radicals in a plasma require multiple expensive and bulky instruments, complex setups, and often, modifications to the plasma reactor. This work presents a simple technique that detects reactive-oxygen radicals incident on a surface from a plasma. The measurements are made using a fluorophore dye that is commonly used in biological and cellular systems for assay labeling in liquids. Using fluorometric analysis, it was found that the fluorophore reacts with oxygen radicals incident from the plasma, which is indicated by degradation of its fluorescence. As plasma power was increased, the quenching of the fluorescence significantly increased. Both immobilized and nonimmobilized fluorophore dyes were used and the results indicate that both states function effectively under vacuum conditions. The reaction mechanism is very similar to that of the liquid dye

  7. Fluorophore-based sensor for oxygen radicals in processing plasmas

    Choudhury, Faraz A.; Shohet, J. Leon, E-mail: shohet@engr.wisc.edu [Plasma Processing and Technology Laboratory and Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Sabat, Grzegorz; Sussman, Michael R. [Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Nishi, Yoshio [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

    2015-11-15

    A high concentration of radicals is present in many processing plasmas, which affects the processing conditions and the properties of materials exposed to the plasma. Determining the types and concentrations of free radicals present in the plasma is critical in order to determine their effects on the materials being processed. Current methods for detecting free radicals in a plasma require multiple expensive and bulky instruments, complex setups, and often, modifications to the plasma reactor. This work presents a simple technique that detects reactive-oxygen radicals incident on a surface from a plasma. The measurements are made using a fluorophore dye that is commonly used in biological and cellular systems for assay labeling in liquids. Using fluorometric analysis, it was found that the fluorophore reacts with oxygen radicals incident from the plasma, which is indicated by degradation of its fluorescence. As plasma power was increased, the quenching of the fluorescence significantly increased. Both immobilized and nonimmobilized fluorophore dyes were used and the results indicate that both states function effectively under vacuum conditions. The reaction mechanism is very similar to that of the liquid dye.

  8. Neutron irradiation characteristic tests of oxygen sensors using zirconia solid electrolyte

    Hiura, Nobuo; Endou, Yasuichi; Yamaura, Takayuki; Niimi, Motoji; Hoshiya, Taiji; Saito, Junichi; Souzawa, Shizuo; Ooka, Norikazu; Kobiyama, Mamoru.

    1997-03-01

    In the Department of JMTR of Japan Atomic Energy Research Institute (JAERI), the in-situ measuring technique of oxygen potential has been being developed to study the chemical behavior of high burn-up fuel base-irradiated in the Light Water Reactor. In this test for development of the technique, oxygen sensors using zirconia solid electrolyte stabilized by MgO, CaO and Y 2 O 3 , named MSZ, CSZ and YSZ, respectively, were irradiated by neutrons in the Japan Materials Testing Reactor (JMTR) of JAERI and the characteristics of electromotive force of these sensors under and after irradiation were discussed. From the experimental results, the electromotive force of YSZ sample under irradiation decreased with an increase in irradiation fluence within a range of neutron fluence (E>1 MeV) up to 1 x 10 23 m -2 . The electromotive force of MSZ sensor irradiated with neutron fluences (E>1 MeV) up to 9 x 10 21 m -2 was almost equal to the theoretical value of the electromotive force. It was shown that after irradiation, a decrease in the electromotive force of CSZ sensor was smaller than those of MSZ and YSZ sensors, although the electromotive forces of MSZ, CSZ and YSZ sensors were smaller than the theoretical value. (author)

  9. Highly sensitive fiber-optic oxygen sensor based on palladium tetrakis (4-carboxyphenyl)porphyrin doped in ormosil

    Chu, Cheng-Shane; Chuang, Chih-Yung

    2014-01-01

    A simple, low-cost technique for fabrication of highly sensitive fiber-optic oxygen sensor is described. An organically modified silicate (ORMOSIL) as a matrix for the fabrication of oxygen sensing film was produced. The technique is based on coating the end of a plastic optical fiber with ormosil composite xerogel film sequestered with luminophore palladium (II) meso-tetra(4-carboxyphenyl)porphyrin (PdTCPP) prepared by a sol–gel process. The composite xerogel studied is tetraethylorthosilane (TEOS)/n-octyltriethoxysilane (Octyl-triEOS). Result shows that, expect for PdTCPP-doped TEOS/Octyl-triEOS composite xerogel show the high sensitivity and linear Stern–Volmer relationship which indicate the homogenous environment of the luminophore. The sensitivity of the optical oxygen sensor is quantified in terms of the ratio I N2 /I O2 , where I N2 and I O2 represent the detected fluorescence intensities in pure nitrogen and pure oxygen environments, respectively. The experimental result reveals that the PdTCPP-doped TEOS/Octyl-triEOS oxygen sensor has sensitivity of 153. - Highlights: • A simple, low-cost technique for fabrication of highly sensitive fiber-optic oxygen sensor is described. • ORMOSIL was produced to serve as a matrix for the fabrication of oxygen sensing film. • The fiber-optic oxygen sensor has sensitivity of I N2 /I 100O2 =153. • The stable and reproducible signals were obtained with the fiber-optic oxygen sensor

  10. Oxygen sensor using proton-conductor thick-film operative at room temperature. Puroton dodentai atsumaku wo mochiita joon sadogata sanso sensor

    Miura, Norio; Yoshida, Nobuaki; Matayoshi, Naoko; Shimizu, Yoichi; Yamazoe, Noboru; Kuwata, Shigeki [Kyushu Univ., Fukuoka, (Japan) Niihama National College of Tech., Ehime, (Japan)

    1989-10-01

    An amperometric solid-state oxygen sensor using a proton-conductor thick-film was examined as a miniaturized and intelligent oxygen sensor operative at room temperature. The good-conditioned proton-conductor film of about 10{mu}m in thickness without holes was formed on a porous alumina substrate by spin-coating the paste containing antimonic acid and a polyvinyl alcohol binder. Using this material, the thick-film oxygen sensor was made. A limiting current, controlled by oxygen permeation through the gas-diffusion layer, was observed when an external voltage was over 1.4V. The limiting current increased linearly with an increase in oxygen partial pressure up to 1.0 atm at an external voltage of 1.6V. The 90% response time for increasing oxygen partial pressure was about 40 seconds at 30 centigrade. Moreover, it was found that the sensor could also respond to dissolved oxygen in water at room temperature. With a sensor using a hydrophobic gas-diffusion layer containing a polystyrene binder, the limiting current was linear to the dissolved oxygen concentration up to 20ppm. 15 refs., 5 figs.

  11. Flexible Sheet-Type Sensor for Noninvasive Measurement of Cellular Oxygen Metabolism on a Culture Dish.

    Mari Kojima

    Full Text Available A novel flexible sensor was developed for the noninvasive oxygen metabolism measurement of cultivated cells and tissues. This device is composed of a transparent double-layered polymer sheet of ethylene-vinyl alcohol (EVOH and poly(dimethylsiloxane (PDMS having an array of microhole structures of 90 μm diameter and 50 μm depth on its surface. All the microhole structures were equipped with a 1-μm-thick optical chemical sensing layer of platinum porphyrin-fluoropolymer on their bottom. The three-dimensional microstructures of the sensor were fabricated by a newly developed simple and low-cost production method named self-aligned hot embossing. The device was designed to be attached slightly above the cells cultivated on a dish to form a temporarily closed microspace over the target cells during measurement. Since the change in oxygen concentration is relatively fast in the microcompartmentalized culture medium, a rapid evaluation of the oxygen consumption rate is possible by measuring the phosphorescence lifetime of the platinum porphyrin-fluoropolymer. The combined use of the device and an automated optical measurement system enabled the high-throughput sensing of cellular oxygen consumption (100 points/min. We monitored the oxygen metabolism of the human breast cancer cell line MCF7 on a Petri dish and evaluated the oxygen consumption rate to be 0.72 ± 0.12 fmol/min/cell. Furthermore, to demonstrate the utility of the developed sensing system, we demonstrated the mapping of the oxygen consumption rate of rat brain slices and succeeded in visualizing a clear difference among the layer structures of the hippocampus, i.e., the cornu ammonis (CA1 and CA3 and dentate gyrus (DG.

  12. Quantifying oxygen in paper-based cell cultures with luminescent thin film sensors.

    Boyce, Matthew W; Kenney, Rachael M; Truong, Andrew S; Lockett, Matthew R

    2016-04-01

    Paper-based scaffolds are an attractive material for generating 3D tissue-like cultures because paper is readily available and does not require specialized equipment to pattern, cut, or use. By controlling the exchange of fresh culture medium with the paper-based scaffolds, we can engineer diffusion-dominated environments similar to those found in spheroids or solid tumors. Oxygen tension directly regulates cellular phenotype and invasiveness through hypoxia-inducible transcription factors and also has chemotactic properties. To date, gradients of oxygen generated in the paper-based cultures have relied on cellular response-based readouts. In this work, we prepared a luminescent thin film capable of quantifying oxygen tensions in apposed cell-containing paper-based scaffolds. The oxygen sensors, which are polystyrene films containing a Pd(II) tetrakis(pentafluorophenyl)porphyrin dye, are photostable, stable in culture conditions, and not cytotoxic. They have a linear response for oxygen tensions ranging from 0 to 160 mmHg O2, and a Stern-Volmer constant (K sv) of 0.239 ± 0.003 mmHg O2 (-1). We used these oxygen-sensing films to measure the spatial and temporal changes in oxygen tension for paper-based cultures containing a breast cancer line that was engineered to constitutively express a fluorescent protein. By acquiring images of the oxygen-sensing film and the fluorescently labeled cells, we were able to approximate the oxygen consumption rates of the cells in our cultures.

  13. Oxygen sensor via the quenching of room-temperature phosphorescence of perdeuterated phenanthrene adsorbed on Whatman 1PS filter paper.

    Ramasamy, S M; Hurtubise, R J

    1998-11-01

    Perdeuterated phenanthrene (d-phen) exhibits strong room-temperature phosphorescence (RTP) when adsorbed on Whatman 1PS filter paper. An oxygen sensor was developed that depends on oxygen quenching of RTP intensity of adsorbed d-phen. The system designed employed a continuous flow of nitrogen or nitrogen-air onto the adsorbed phosphor. The sensor is simple to prepare and needs no elaborate fabrication procedure, but did show a somewhat drifting baseline for successive determinations of oxygen. Nevertheless, very good reproducibility was achieved with the RTP quenching data by measuring the RTP intensities just before and at the end of each oxygen determination. The calibration plots gave a nonlinear relationship over the entire range of oxygen (0-21%). However, a linear range was obtained up to 1.10% oxygen. A detection limit of 0.09% oxygen in dry nitrogen was acquired. Also, carbon dioxide was found to have a minimal effect on the RTP quenching. Thus, oxygen could be measured accurately in relatively large amounts of carbon dioxide. The performance of the oxygen sensor was evaluated by comparing data obtained with a commercial electrochemical trace oxygen analyzer. Also, additional information on the quenching phenomena for this system was obtained from the RTP lifetime data acquired at various oxygen contents.

  14. Steady-state modelling of the universal exhaust gas oxygen (UEGO) sensor

    Collings, N; Hegarty, K; Ramsander, T

    2012-01-01

    The universal exhaust gas oxygen (UEGO) sensor is a well-established device which was developed for the measurement of relative air fuel ratio in internal combustion engines. There is, however, little information available which allows for the prediction of the UEGO's behaviour when exposed to arbitrary gas mixtures, pressures and temperatures. Here we present a steady-state model for the sensor, based on a solution of the Stefan–Maxwell equation, and which includes a momentum balance. The response of the sensor is dominated by a diffusion barrier, which controls the rate of diffusion of gas species between the exhaust and a cavity. Determination of the diffusion barrier characteristics, especially the mean pore size, porosity and tortuosity, is essential for the purposes of modelling, and a measurement technique based on identification of the sensor pressure giving zero temperature sensitivity is shown to be a convenient method of achieving this. The model, suitably calibrated, is shown to make good predictions of sensor behaviour for large variations of pressure, temperature and gas composition. (paper)

  15. Performance Evaluation of an Oxygen Sensor as a Function of the Samaria Doped Ceria Film Thickness

    Sanghavi, Rahul P.; Nandasiri, Manjula I.; Kuchibhatla, Satyanarayana; Nachimuthu, Ponnusamy; Engelhard, Mark H.; Shutthanandan, V.; Jiang, Weilin; Thevuthasan, Suntharampillai; Kayani, Asghar N.; Prasad, Shalini

    2010-01-01

    The current demand in the automobile industry is in the control of air-fuel mixture in the combustion engine of automobiles. Oxygen partial pressure can be used as an input parameter for regulating or controlling systems in order to optimize the combustion process. Our goal is to identify and optimize the material system that would potentially function as the active sensing material for such a device that monitors oxygen partial pressure in these systems. We have used thin film samaria doped ceria (SDC) as the sensing material for the sensor operation, exploiting the fact that at high temperatures, oxygen vacancies generated due to samarium doping act as conducting medium for oxygen ions which hop through the vacancies from one side to the other contributing to an electrical signal. We have recently established that 6 atom% Sm doping in ceria films has optimum conductivity. Based on this observation, we have studied the variation in the overall conductivity of 6 atom% samaria doped ceria thin films as a function of thickness in the range of 50 nm to 300 nm at a fixed bias voltage of 2 volts. A direct proportionality in the increase in the overall conductivity is observed with the increase in sensing film thickness. For a range of oxygen pressure values from 1 mTorr to 100 Torr, a tolerable hysteresis error, good dynamic response and a response time of less than 10 seconds was observed

  16. Integrated oxygen sensors based on Mg-doped SrTiO3 fabricated by screen-printing

    Zheng, H.; Toft Sørensen, O.

    1998-01-01

    This paper describes the fabrication and testing of Mg-doped SrTiO3 thick-film oxygen sensors with an integrated Pt heater. The results show that the sensor exhibits a PO2 dependence according to R proportional to PO2-1/4 in the considered PO2 range(2.5 x 10(-5) bar

  17. Development of oxygen and pH sensors for aqueous systems

    Stvartak, C.; Alcock, C.B.; Li, B.; Wang, L.; Fergus, J.W.; Bakshi, N.

    1994-04-01

    Corrosion science has long recognized that two of the most important parameters in characterizing the corrosivity of an aqueous environment are oxygen chemical potential and pH. These parameters not only determine the thermodynamic driving forces for various corrosion reactions, but also characterize the rates of these reactions and hence the lifetime of a particular component. The primary goal of this project is to develop an electrochemical oxygen and pH sensor for continuous use in the cycle chemistry control of power plants. In the past year, electrochemical sensors with a metal/metal oxide or metal/metal hydride internal reference electrode and a fluoride-based electrolyte tube have been developed and tested in this laboratory. The corrosion tests showed that the LaF 3 -based solid electrolyte was very stable both chemically and physically in water. Furthermore, its electrical conductivity is 4 to 5 orders of magnitude higher than that of stabilized zirconia below 573 K (300 degree C), which is the main advantage of a fluoride-based electrolyte at low temperatures. With this electrolyte and the selected internal oxygen reference electrode (Ag/Ag 2 O), the electrochemical probe demonstrated Nernstian responses to the oxygen chemical potential and pH of the aqueous solution with good reproducibility. A similar cell with Zr/ZrH 1+x as the internal hydrogen reference electrode showed promising pH sensing characteristics. It is proposed that these two cells be combined to form a double-headed electrochemical probe to determine oxygen chemical potential and pH in the solution simultaneously

  18. An optode sensor array for long term in situ Oxygen measurements in soil and sediment

    Rickelt, Lars F; Jensen, Louise Askær; Walpersdorf, Eva Christine

    2013-01-01

    Long-term measurements of molecular oxygen (O2) dynamics in wetlands are highly relevant for understanding the eff ects of water level changes on net greenhouse gas budgets in these ecosystems. However, such measurements have been limited due to a lack of suitable measuring equipment. We construc......Long-term measurements of molecular oxygen (O2) dynamics in wetlands are highly relevant for understanding the eff ects of water level changes on net greenhouse gas budgets in these ecosystems. However, such measurements have been limited due to a lack of suitable measuring equipment. We...... constructed an O2 optode sensor array for long-term in situ measurements in soil and sediment. Th e new device consists of a 1.3-m-long, cylindrical, spear-shaped rod equipped with 10 sensor spots along the shaft . Each spot contains a thermocouple fi xed with a robust fi beroptic O2 optode made...... characteristics of the sensor array system are presented along with a novel approach for temperature compensation of O2 optodes. During in situ application over several months in a peat bog, we used the new device to document pronounced variations in O2 distribution aft er marked shift s in water level. Th e...

  19. Microfabricated Collector-Generator Electrode Sensor for Measuring Absolute pH and Oxygen Concentrations.

    Dengler, Adam K; Wightman, R Mark; McCarty, Gregory S

    2015-10-20

    Fast-scan cyclic voltammetry (FSCV) has attracted attention for studying in vivo neurotransmission due to its subsecond temporal resolution, selectivity, and sensitivity. Traditional FSCV measurements use background subtraction to isolate changes in the local electrochemical environment, providing detailed information on fluctuations in the concentration of electroactive species. This background subtraction removes information about constant or slowly changing concentrations. However, determination of background concentrations is still important for understanding functioning brain tissue. For example, neural activity is known to consume oxygen and produce carbon dioxide which affects local levels of oxygen and pH. Here, we present a microfabricated microelectrode array which uses FSCV to detect the absolute levels of oxygen and pH in vitro. The sensor is a collector-generator electrode array with carbon microelectrodes spaced 5 μm apart. In this work, a periodic potential step is applied at the generator producing transient local changes in the electrochemical environment. The collector electrode continuously performs FSCV enabling these induced changes in concentration to be recorded with the sensitivity and selectivity of FSCV. A negative potential step applied at the generator produces a transient local pH shift at the collector. The generator-induced pH signal is detected using FSCV at the collector and correlated to absolute solution pH by postcalibration of the anodic peak position. In addition, in oxygenated solutions a negative potential step at the generator produces hydrogen peroxide by reducing oxygen. Hydrogen peroxide is detected with FSCV at the collector electrode, and the magnitude of the oxidative peak is proportional to absolute oxygen concentrations. Oxygen interference on the pH signal is minimal and can be accounted for with a postcalibration.

  20. Net community production at Ocean Station Papa observed with nitrate and oxygen sensors on profiling floats

    Plant, Joshua N.; Johnson, Kenneth S.; Sakamoto, Carole M.; Jannasch, Hans W.; Coletti, Luke J.; Riser, Stephen C.; Swift, Dana D.

    2016-06-01

    Six profiling floats equipped with nitrate and oxygen sensors were deployed at Ocean Station P in the Gulf of Alaska. The resulting six calendar years and 10 float years of nitrate and oxygen data were used to determine an average annual cycle for net community production (NCP) in the top 35 m of the water column. NCP became positive in February as soon as the mixing activity in the surface layer began to weaken, but nearly 3 months before the traditionally defined mixed layer began to shoal from its winter time maximum. NCP displayed two maxima, one toward the end of May and another in August with a summertime minimum in June corresponding to the historical peak in mesozooplankton biomass. The average annual NCP was determined to be 1.5 ± 0.6 mol C m-2 yr-1 using nitrate and 1.5 ± 0.7 mol C m-2 yr-1 using oxygen. The results from oxygen data proved to be quite sensitive to the gas exchange model used as well as the accuracy of the oxygen measurement. Gas exchange models optimized for carbon dioxide flux generally ignore transport due to gas exchange through the injection of bubbles, and these models yield NCP values that are two to three time higher than the nitrate-based estimates. If nitrate and oxygen NCP rates are assumed to be related by the Redfield model, we show that the oxygen gas exchange model can be optimized by tuning the exchange terms to reproduce the nitrate NCP annual cycle.

  1. Engineering glucose oxidase to minimize the influence of oxygen on sensor response

    Horaguchi, Yohei; Saito, Shoko; Kojima, Katsuhiro; Tsugawa, Wakako; Ferri, Stefano; Sode, Koji

    2014-01-01

    Glucose oxidase (GOx) is an important industrial enzyme and is recognized as the gold standard for monitoring blood glucose. However, due to its inherent oxidase property, the presence of oxygen affects electrochemical measurements of venous blood glucose employing artificial electron mediators. We therefore attempted to engineer Penicillium amagasakiense-derived GOx into a dehydrogenase by focusing on the amino acid residues predicted to interact with oxygen. Our rational amino acid substitution approach resulted in the construction of the Ser114Ala/Phe355Leu mutant, which has an 11-fold decrease in oxidase activity and 2.8-fold increase in dehydrogenase activity compared with wild-type GOx. As a result, the dehydrogenase/oxidase activity ratio of the engineered enzyme was 32-fold greater than that of the wild-type enzyme. The enzyme sensor constructed with Ser114Ala/Phe355Leu was considerably less affected by oxygen than the wild-type GOx-based sensor at lower glucose concentrations

  2. Methods and Best Practice to Intercompare Dissolved Oxygen Sensors and Fluorometers/Turbidimeters for Oceanographic Applications

    Sara Pensieri

    2016-05-01

    Full Text Available In European seas, ocean monitoring strategies in terms of key parameters, space and time scale vary widely for a range of technical and economic reasons. Nonetheless, the growing interest in the ocean interior promotes the investigation of processes such as oxygen consumption, primary productivity and ocean acidity requiring that close attention is paid to the instruments in terms of measurement setup, configuration, calibration, maintenance procedures and quality assessment. To this aim, two separate hardware and software tools were developed in order to test and simultaneously intercompare several oxygen probes and fluorometers/turbidimeters, respectively in the same environmental conditions, with a configuration as close as possible to real in-situ deployment. The chamber designed to perform chlorophyll-a and turbidity tests allowed for the simultaneous acquisition of analogue and digital signals of several sensors at the same time, so it was sufficiently compact to be used in both laboratory and onboard vessels. Methodologies and best practice committed to the intercomparison of dissolved oxygen sensors and fluorometers/turbidimeters have been used, which aid in the promotion of interoperability to access key infrastructures, such as ocean observatories and calibration facilities. Results from laboratory tests as well as field tests in the Mediterranean Sea are presented.

  3. Composite Sr- and V-doped LaCrO3/YSZ sensor electrode operating at low oxygen levels

    Lund, Anders; Jacobsen, Torben; Hansen, Karin Vels

    2012-01-01

    A porous composite electrode of La0.8Sr0.2Cr0.97V0.03O3 -delta (LSCV) and yttria-stabilised zirconia (YSZ) was evaluated as a possible candidate for high-temperature potentiometric oxygen sensor measuring electrodes. The oxygen processes at the electrode were characterised by performing electroch....... The relatively low response time at 700º C at an oxygen partial pressure of around 5x10-6 bar and an inlet gas flow rate of 8 L h-1 makes the LSCV/YSZ electrode suitable for use as an potentiometric oxygen sensor electrodes.......A porous composite electrode of La0.8Sr0.2Cr0.97V0.03O3 -delta (LSCV) and yttria-stabilised zirconia (YSZ) was evaluated as a possible candidate for high-temperature potentiometric oxygen sensor measuring electrodes. The oxygen processes at the electrode were characterised by performing...... and 400 nm. At oxygen partial pressures around 0.2 bar at 700º C, the oxygen reaction is dominated by solid-state diffusion of oxide ions and surface reaction kinetics. At oxygen partial pressures around 10-5 bar above 800º C, gas phase mass transport processes dominate the impedance spectra...

  4. A laser-based sensor for measurement of off-gas composition and temperature in basic oxygen steelmaking

    Ottesen, D.; Allendorf, S.; Ludowise, P.; Hardesty, D.; Miller, T.; Goldstein, D.; Smith, C.; Bonin, M.

    1999-01-01

    We are developing an optical sensor for process control in basic oxygen steelmaking. The sensor measures gas temperature and relative CO/CO 2 concentration ratios in the furnace off-gas by transmitting the laser probe beam directly above the furnace lip and below the exhaust hood during oxygen blowing. Dynamic off-gas information is being evaluated for optimizing variables such as lance height, oxygen flow, post-combustion control, and prediction of final melt-carbon content. The non-invasive nature of the optical sensor renders it robust and relatively maintenance-free. Additional potential applications of the method are process control for electric arc furnace and bottom-blown oxygen steelmaking processes. (author)

  5. Nanostructured oxygen sensor--using micelles to incorporate a hydrophobic platinum porphyrin.

    Fengyu Su

    Full Text Available Hydrophobic platinum(II-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorophenyl-porphyrin (PtTFPP was physically incorporated into micelles formed from poly(ε-caprolactone-block-poly(ethylene glycol to enable the application of PtTFPP in aqueous solution. Micelles were characterized using dynamic light scattering (DLS and atomic force microscopy (AFM to show an average diameter of about 140 nm. PtTFPP showed higher quantum efficiency in micellar solution than in tetrahydrofuran (THF and dichloromethane (CH₂Cl₂. PtTFPP in micelles also exhibited higher photostability than that of PtTFPP suspended in water. PtTFPP in micelles exhibited good oxygen sensitivity and response time. This study provided an efficient approach to enable the application of hydrophobic oxygen sensors in a biological environment.

  6. Microbial nar-GFP cell sensors reveal oxygen limitations in highly agitated and aerated laboratory-scale fermentors

    Rao Govind

    2009-01-01

    Full Text Available Abstract Background Small-scale microbial fermentations are often assumed to be homogeneous, and oxygen limitation due to inadequate micromixing is often overlooked as a potential problem. To assess the relative degree of micromixing, and hence propensity for oxygen limitation, a new cellular oxygen sensor has been developed. The oxygen responsive E. coli nitrate reductase (nar promoter was used to construct an oxygen reporter plasmid (pNar-GFPuv which allows cell-based reporting of oxygen limitation. Because there are greater than 109 cells in a fermentor, one can outfit a vessel with more than 109 sensors. Our concept was tested in high density, lab-scale (5 L, fed-batch, E. coli fermentations operated with varied mixing efficiency – one verses four impellers. Results In both cases, bioreactors were maintained identically at greater than 80% dissolved oxygen (DO during batch phase and at approximately 20% DO during fed-batch phase. Trends for glucose consumption, biomass and DO showed nearly identical behavior. However, fermentations with only one impeller showed significantly higher GFPuv expression than those with four, indicating a higher degree of fluid segregation sufficient for cellular oxygen deprivation. As the characteristic time for GFPuv expression (approx 90 min. is much larger than that for mixing (approx 10 s, increased specific fluorescence represents an averaged effect of oxygen limitation over time and by natural extension, over space. Conclusion Thus, the pNar-GFPuv plasmid enabled bioreactor-wide oxygen sensing in that bacterial cells served as individual recirculating sensors integrating their responses over space and time. We envision cell-based oxygen sensors may find utility in a wide variety of bioprocessing applications.

  7. Low cost chemical oxygen demand sensor based on electrodeposited nano-copper film

    Hamdy H. Hassan

    2018-02-01

    Full Text Available A commercially available copper electrical cable and pure Cu disk were used as substrates for the electrodeposition of copper nanoparticles (nano-Cu. The surface morphology of the prepared nano-Cu/Cu electrodes was investigated by scanning electron microscope (SEM and energy dispersive X-ray spectrometer (EDX. The bare copper substrates and the nano-copper modified electrodes were utilized and optimized for electrochemical assay of chemical oxygen demand (COD using glycine as a standard. A comparison was made among the four electrodes (i.e., bare and nano-Cu coated copper cable and pure copper disk as potential COD sensors. The oxidation behavior of glycine was investigated on the surface of the prepared sensors using linear sweep voltammetry (LSV. The results indicate significant enhancement of the electrochemical oxidation of glycine by the deposited nano-Cu. The effects of different deposition parameters, such as Cu2+ concentration, deposition potential, deposition time, pH, and scan rate on the response of the prepared sensors were investigated. Under optimized conditions, the optimal nano-Cu based COD sensor exhibited a linear range of 2–595 mg/L, lower limit of detection (LOD as low as 1.07 mg/L (S/N = 3. The developed method exhibited high tolerance level to Cl− ion where 1.0 M Cl− exhibited minimal influence. The sensor was utilized for the detection of COD in different real water samples. The results obtained were validated using the standard dichromate method.

  8. Plasmonic detection and visualization of directed adsorption of charged single nanoparticles to patterned surfaces

    Scherbahn, Vitali; Nizamov, Shavkat; Mirsky, Vladimir M.

    2016-01-01

    It has recently been shown that surface plasmon microscopy (SPM) allows single nanoparticles (NPs) on sensor surfaces to be detected and analyzed. The authors have applied this technique to study the adsorption of single metallic and plastic NPs. Binding of gold NPs (40, 60 and 100 nm in size) and of 100 nm polystyrene NPs to gold surfaces modified by differently ω-functionalized alkyl thiols was studied first. Self-assembled monolayers (SAM) with varying terminal functions including amino, carboxy, oligo(ethylene glycol), methyl, or trimethylammonium groups were deposited on gold films to form surfaces possessing different charge and hydrophobicity. The affinity of NPs to these surfaces depends strongly on the type of coating. SAMs terminated with trimethylammonium groups and carboxy group display highly different affinity and therefore were preferred when creating patterned charged surfaces. Citrate-stabilized gold NPs and sulfate-terminated polystyrene NPs were used as negatively charged NPs, while branched polyethylenimine-coated silver NPs were used as positively charged NPs. It is shown that the charged patterned areas on the gold films are capable of selectively adsorbing oppositely charged NPs that can be detected and analyzed with an ∼1 ng⋅mL −1 detection limit. (author)

  9. Optical monitoring of kidney oxygenation and hemodynamics using a miniaturized near-infrared sensor

    Shadgan, Babak; Macnab, Andrew; Nigro, Mark; Nguan, Christopher

    2017-02-01

    Background: Following human renal allograft transplant primary graft dysfunction can occur early in the postoperative period as a result of acute tubular necrosis, acute rejection, drug toxicity, and vascular complications. Successful treatment of graft dysfunction requires early detection and accurate diagnosis so that disease-specific medical and/or surgical intervention can be provided promptly. However, current diagnostic methods are not sensitive or specific enough, so that identifying the cause of graft dysfunction is problematic and often delayed. Near-infrared spectroscopy (NIRS) is an established optical method that monitors changes in tissue hemodynamics and oxygenation in real time. We report the feasibility of directly monitoring kidney the kidney in an animal model using NIRS to detect renal ischemia and hypoxia. Methods: In an anesthetized pig, a customized continuous wave spatially resolved (SR) NIRS sensor was fixed directly to the surface of the surgically exposed kidney. Changes in the concentration of oxygenated (O2Hb) deoxygenated (HHb) and total hemoglobin (THb) were monitored before, during and after renal artery clamping and reperfusion, and the resulting fluctuations in chromophore concentration from baseline used to measure variations in renal perfusion and oxygenation. Results: On clamping the renal artery THb and O2Hb concentrations declined progressively while HHb rose. With reperfusion after releasing the artery clamp O2Hb and THb rose while HHb fell with all parameters returning to its baseline. This pattern was similar in all three trials. Conclusion: This pilot study indicates that a miniaturized NIRS sensor applied directly to the surface of a kidney in an animal model can detect the onset of renal ischemia and tissue hypoxia. With modification, our NIRS-based method may contribute to early detection of renal vascular complications and graft dysfunction following renal transplant.

  10. Study on the inside gas flow visualization of oxygen sensor cover; Kashika ni yoru O2 sensor cover nai no gas nagare hyoka

    Hocho, S; Mitsuishi, Y; Inagaki, M [Nippon Soken, Inc., Tokyo (Japan); Hamaguchi, S; Mizusawa, K [Toyota Motor Corp., Aichi (Japan)

    1997-10-01

    In order to make clear the difference of the response time between the oxygen sensors with different protection covers, we visualized gas flow inside of sensor covers by means of two experimental methods: One is `Smoke Suspension Method` using liquid paraffin vapor as the smoke. With smoke suspension method, we detected the streamlines inside of the covers. The other is `Color Reaction Method` using the reaction of phenolphthalein and NH3 gas. With color reaction method, we confirmed the streamline inside of the cover and furthermore detected the difference of the response time of each sensor. 3 refs., 7 figs., 1 tab.

  11. Elaboration and characterization of solid electrolytes for electrochemical oxygen sensors in liquid sodium

    Gabard, M.

    2013-01-01

    This PhD thesis was prepared within the framework of the research program on 'Generation IV' nuclear reactors with sodium as coolant. One of the main technological problem concerns the control of the corrosion processes of the materials (structural materials, fuel claddings, etc.) by liquid sodium. A key parameter is the dissolved oxygen content in the coolant. This thesis focuses on the development and characterization of ceramic materials based on ThO 2 doped with Y 2 O 3 for making potentiometric oxygen sensor used in liquid sodium. Work has been carried out and probes were tested in the past, however, the probes had at the time, a lack of reliability. The objective of this thesis is to develop and characterize electrolytes based on thorium oxide doped with yttrium oxide using specific synthesis techniques to control purity, grain size, compactness, etc. To develop experimental protocols a ceramic model has been chosen, i.e., yttria-doped ceria. Transport processes were studied using the impedance spectroscopy technique. An interpretation of the blocking phenomena of the ionic conduction in both ceramics as a function of the oxygen partial pressure has been given. (author) [fr

  12. Subpicosecond oxygen trapping in the heme pocket of the oxygen sensor FixL observed by time-resolved resonance Raman spectroscopy.

    Kruglik, Sergei G; Jasaitis, Audrius; Hola, Klara; Yamashita, Taku; Liebl, Ursula; Martin, Jean-Louis; Vos, Marten H

    2007-05-01

    Dissociation of oxygen from the heme domain of the bacterial oxygen sensor protein FixL constitutes the first step in hypoxia-induced signaling. In the present study, the photodissociation of the heme-O2 bond was used to synchronize this event, and time-resolved resonance Raman (TR(3)) spectroscopy with subpicosecond time resolution was implemented to characterize the heme configuration of the primary photoproduct. TR(3) measurements on heme-oxycomplexes are highly challenging and have not yet been reported. Whereas in all other known six-coordinated heme protein complexes with diatomic ligands, including the oxymyoglobin reported here, heme iron out-of-plane motion (doming) occurs faster than 1 ps after iron-ligand bond breaking; surprisingly, no sizeable doming is observed in the oxycomplex of the Bradyrhizobium japonicum FixL sensor domain (FixLH). This assessment is deduced from the absence of the iron-histidine band around 217 cm(-1) as early as 0.5 ps. We suggest that efficient ultrafast oxygen rebinding to the heme occurs on the femtosecond time scale, thus hindering heme doming. Comparing WT oxy-FixLH, mutant proteins FixLH-R220H and FixLH-R220Q, the respective carbonmonoxy-complexes, and oxymyoglobin, we show that a hydrogen bond of the terminal oxygen atom with the residue in position 220 is responsible for the observed behavior; in WT FixL this residue is arginine, crucially implicated in signal transmission. We propose that the rigid O2 configuration imposed by this residue, in combination with the hydrophobic and constrained properties of the distal cavity, keep dissociated oxygen in place. These results uncover the origin of the "oxygen cage" properties of this oxygen sensor protein.

  13. Integrated oxygen sensors based on Mg-doped SrTiO3 fabricated by screen-printing

    Zheng, H.; Sørensen, Ole Toft

    2000-01-01

    This paper describes the fabrication and testing of Mg-doped SrTiO3 thick-film oxygen sensors with an integrated Pt heater. The results show that the sensor exhibits a P-o2 dependence according to R proportional to p(o2)(-1/4) in the considered P-o2 range(2.5 x 10(-5) bar

  14. A flowing liquid test system for assessing the linearity and time-response of rapid fibre optic oxygen partial pressure sensors.

    Chen, R; Hahn, C E W; Farmery, A D

    2012-08-15

    The development of a methodology for testing the time response, linearity and performance characteristics of ultra fast fibre optic oxygen sensors in the liquid phase is presented. Two standard medical paediatric oxygenators are arranged to provide two independent extracorporeal circuits. Flow from either circuit can be diverted over the sensor under test by means of a system of rapid cross-over solenoid valves exposing the sensor to an abrupt change in oxygen partial pressure, P O2. The system is also capable of testing the oxygen sensor responses to changes in temperature, carbon dioxide partial pressure P CO2 and pH in situ. Results are presented for a miniature fibre optic oxygen sensor constructed in-house with a response time ≈ 50 ms and a commercial fibre optic sensor (Ocean Optics Foxy), when tested in flowing saline and stored blood. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. First experience with a novel luminescence-based optical sensor for measurement of oxygenation in tumors

    Jarm, T.; Miklavcic, D.; Lesnicar, H.; Sersa, G.

    2001-01-01

    Background. The purpose of this preliminary study was to evaluate a novel luminescence-based fiber-optic sensor (OxyLite system) for the measurement of partial pressure of oxygen (pO 2 ) in tumors and for the detection of changes in pO 2 as a function of time. The new method was used simultaneously with the laser Doppler flowmetry method for the measurement of relative tissue perfusion. Materials and methods. Blood perfusion and pO 2 were measured continuously via fiber-optic sensors inserted into SA-1 tumors in anesthetized A/J mice. The changes in blood flow and oxygenation of tumors were induced by transient changes of the parameters of anesthesia and by injection of a vasoactive drug hydralazine. Results. Both optical methods used in the study successfully detected the induced changes in blood flow and pO 2 . The measurements of pO 2 were well correlated with measurements of microcirculatory blood perfusion. In the majority of pO 2 measurements, we observed an unexpected behavior of the signal during the stabilization process immediately after the insertion of the probe into tumor. This behaviour of the pO 2 signal was most probably caused by local tissue damage induced by the insertion of the probe. Conclusion. The novel luminescence-based optical oximetry can reliably detect local pO 2 changes in tumors as a function of time but some aspects of prolonged pO 2 measurement by this method require further investigation. (author)

  16. THE DEVELOPMENT OF BIOCHEMICAL OXYGEN DEMAND SENSOR USING LOCAL YEAST: Candida fukuyamaensis, UICC Y-247

    Endang Saepudin

    2011-04-01

    Full Text Available In order to shorten the measurement time of biochemical oxygen demand (BOD, a BOD sensor based on yeastmetabolism was developed. Local yeast, Indonesian Origin, Candida fukuyamaensis UICC Y-247, was used as atransducer. The yeast was immobilized as a thin film in agarose matrix with the auxiliary of Nafion® acting as themembrane for ion exchange process. The film was then attached to gold-modified glassy carbons and used as transduceron the working electrodes. The measurements were conducted by observing the depletion of glucose concentrationusing multipulse amperometric method and then converted to BOD values. Optimum condition was observed in awaiting measurement time of 30 min at an applied potential of 450 mV (vs. Ag/AgCl. Linearity was shown in glucoseconcentration range of 0.1–0.5 mM, which was equivalent to BOD concentration range of 10–50 mg/L. A detectionlimit of 1.13 mg/L BOD could be achieved. Good repeatability was shown by a relative standard deviation (RSD of2.7% (n = 15. However, decreasing current response of ~50% was found after 3 days. Comparing to the conventionalBOD measurement, this BOD sensor can be used as an alternative method for BOD measurements.

  17. Phosphorus doped TiO2 as oxygen sensor with low operating temperature and sensing mechanism

    Han, Zhizhong; Wang, Jiejie; Liao, Lan; Pan, Haibo; Shen, Shuifa; Chen, Jianzhong

    2013-01-01

    Nano-scale TiO 2 powders doped with phosphorus were prepared by sol–gel method. The characterization of the materials was performed by XRD, BET, FT-IR spectroscopy, Zeta potential measurement and XPS analysis. The results indicate that the phosphorus suppresses the crystal growth and phase transformation and, at the same time, increases the surface area and enhances the sensitivity and selectivity for the P-doped TiO 2 oxygen sensors. In this system, the operating temperature is low, only 116 °C, and the response time is short. The spectra of FT-IR and XPS show that the phosphorus dopant presents as the pentavalent-oxidation state in TiO 2 , further phosphorus can connect with Ti 4+ through the bond of Ti-O-P. The positive shifts of XPS peaks indicate that electron depleted layer of P-doped TiO 2 is narrowed compared with that of pure TiO 2 , and the results of Zeta potential illuminate that the density of surface charge carrier is intensified. The adsorptive active site and Lewis acid characteristics of the surface are reinforced by phosphorus doping, where phosphorus ions act as a new active site. Thus, the sensitivity of P-doped TiO 2 is improved, and the 5 mol% P-doped sample has the optimal oxygen sensing properties.

  18. Nanosized TiO[subscript 2] for Photocatalytic Water Splitting Studied by Oxygen Sensor and Data Logger

    Zhang, Ruinan; Liu, Song; Yuan, Hongyan; Xiao, Dan; Choi, Martin M. F.

    2012-01-01

    Photocatalytic water splitting by semiconductor photocatalysts has attracted considerable attention in the past few decades. In this experiment, nanosized titanium dioxide (nano-TiO[subscript 2]) particles are used to photocatalytically split water, which is then monitored by an oxygen sensor. Sacrificial reagents such as organics (EDTA) and metal…

  19. Using micro-patterned sensors and cell self-assembly for measuring the oxygen consumption rate of single cells

    Etzkorn, James R; Parviz, Babak A; Wu, Wen-Chung; Tian, Zhiyuan; Kim, Prince; Jang, Sei-Hum; Jen, Alex K-Y; Meldrum, Deirdre R

    2010-01-01

    We present a method for self-assembling arrays of live single cells on a glass chip using a photopatternable polymer to form micro-traps. We have studied the single-cell self-assembly method and optimized the process to obtain a 52% yield of single-trapped cells. We also report a method to measure the oxygen consumption rate of a single cell using micro-patterned sensors. These molecular oxygen sensors were fabricated around each micro-trap allowing optical interrogation of oxygen concentration in the immediate environment of the trapped cell. Micromachined micro-wells were then used to seal the trap, sensor and cell in order to determine the oxygen consumption rate of single cells. These techniques reported here add to the collection of tools for performing 'singe-cell' biology. An oxygen consumption rate of 1.05 ± 0.28 fmol min −1 was found for a data set consisting of 25 single A549 cells.

  20. Hydrogen generation monitoring and mass gain analysis during the steam oxidation for Zircaloy using hydrogen and oxygen sensors

    Fukumoto, Michihisa; Hara, Motoi; Kaneko, Hiroyuki; Sakuraba, Takuya

    2015-01-01

    The oxidation behavior of Zircaloy-4 at high temperatures in a flowing Ar-H_2O (saturated at 323 K) mixed gas was investigated using hydrogen and oxygen sensors installed at a gas outlet, and the utility of the gas sensing methods by using both sensors was examined. The generated amount of hydrogen was determined from the hydrogen partial pressure continuously measured by the hydrogen sensor, and the resultant calculated oxygen amount that reacted with the specimen was in close agreement with the mass gain gravimetrically measured after the experiment. This result demonstrated that the hydrogen partial pressure measurement using a hydrogen sensor is an effective method for examining the steam oxidation of this metal as well as monitoring the hydrogen evolution. The advantage of this method is that the oxidation rate of the metal at any time as a differential quantity is able to be obtained, compared to the oxygen amount gravimetrically measured as an integral quantity. When the temperature was periodically changed in the range of 1173 K to 1523 K, highly accurate measurements could be carried out using this gas monitoring method, although reasonable measurements were not gravimetrically performed due to the fluctuating thermo-buoyancy during the experiment. A change of the oxidation rate was clearly detected at a monoclinic tetragonal transition temperature of ZrO_2. From the calculation of the water vapor partial pressure during the thermal equilibrium condition using the hydrogen and oxygen partial pressures, it became clear that a thermal equilibrium state is maintained when the isothermal condition is maintained, but is not when the temperature increases or decreases with time. Based on these results, it was demonstrated that the gas monitoring system using hydrogen and oxygen sensors is very useful for investigating the oxidation process of the Zircaloy in steam. (author)

  1. Oxygen partial pressure effects on the RF sputtered p-type NiO hydrogen gas sensors

    Turgut, Erdal; Çoban, Ömer; Sarıtaş, Sevda; Tüzemen, Sebahattin; Yıldırım, Muhammet; Gür, Emre

    2018-03-01

    NiO thin films were grown by Radio Frequency (RF) Magnetron Sputtering method under different oxygen partial pressures, which are 0.6 mTorr, 1.3 mTorr and 2.0 mTorr. The effects of oxygen partial pressures on the thin films were analyzed through Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS) and Hall measurements. The change in the surface morphology of the thin films has been observed with the SEM and AFM measurements. While nano-pyramids have been obtained on the thin film grown at the lowest oxygen partial pressure, the spherical granules lower than 60 nm in size has been observed for the samples grown at higher oxygen partial pressures. The shift in the dominant XRD peak is realized to the lower two theta angle with increasing the oxygen partial pressures. XPS measurements showed that the Ni2p peak involves satellite peaks and two oxidation states of Ni, Ni2+ and Ni3+, have been existed together with the corresponding splitting in O1s spectrum. P-type conductivity of the grown NiO thin films are confirmed by the Hall measurements with concentrations on the order of 1013 holes/cm-3. Gas sensor measurements revealed minimum of 10% response to the 10 ppm H2 level. Enhanced responsivity of the gas sensor devices of NiO thin films is shown as the oxygen partial pressure increases.

  2. New hybrid reflectance optical pulse oximetry sensor for lower oxygen saturation measurement and for broader clinical application

    Nogawa, Masamichi; Ching, Chong Thong; Ida, Takeyuki; Itakura, Keiko; Takatani, Setsuo

    1997-06-01

    A new reflectance pulse oximeter sensor for lower arterial oxygen saturation (Sa)2) measurement has been designed and evaluated in animals prior to clinical trials. The new sensor incorporates ten light emitting diode chips for each wavelength of 730 and 880 nm mounted symmetrically and at the radial separation distance of 7 mm around a photodiode chip. The separation distance of 7 mm was chosen to maximize the ratio of the pulsatile to the average plethysmographic signal level at each wavelength. The 730 and 880 wavelength combination was determined to obtain a linear relationship between the reflectance ratio of the 730 and 880 nm wavelengths and Sa)2. In addition to these features of the sensor, the Fast Fourier Transform method was employed to compute the pulsatile and average signal level at each wavelength. The performance of the new reflectance pulse oximeter sensor was evaluated in dogs in comparison to the 665/910 nm sensor. As predicted by the theoretical simulation based on a 3D photon diffusion theory, the 730/880 nm sensor demonstrated an excellent linearity over the SaO2 range from 100 to 30 percent. For the SaO2 range between 100 and 70 percent, the 665/910 and 730/880 sensors showed the standard error of around 3.5 percent and 2.1 percent, respectively, in comparison to the blood samples. For the range between 70 and 30 percent, the standard error of the 730/880 nm sensor was only 2.7 percent, while that of the 665/910 nm sensor was 9.5 percent. The 730/880 sensor showed improved accuracy for a wide range of SaO2 particularly over the range between 70 and 30 percent. This new reflectance sensor can provide noninvasive measurement of SaO2 accurately over the wide saturation range from 100 to 30 percent.

  3. Design parameters for voltage-controllable directed assembly of single nanoparticles

    Porter, Benjamin F; Bhaskaran, Harish; Abelmann, Leon

    2013-01-01

    Techniques to reliably pick-and-place single nanoparticles into functional assemblies are required to incorporate exotic nanoparticles into standard electronic circuits. In this paper we explore the use of electric fields to drive and direct the assembly process, which has the advantage of being able to control the nano-assembly process at the single nanoparticle level. To achieve this, we design an electrostatic gating system, thus enabling a voltage-controllable nanoparticle picking technique. Simulating this system with the nonlinear Poisson–Boltzmann equation, we can successfully characterize the parameters required for single particle placement, the key being single particle selectivity, in effect designing a system that can achieve this controllably. We then present the optimum design parameters required for successful single nanoparticle placement at ambient temperature, an important requirement for nanomanufacturing processes. (paper)

  4. Novel nanostructured materials to develop oxygen-sensitive films for optical sensors

    Fernandez-Sanchez, Jorge F.; Cannas, Rita; Spichiger, Stefan; Steiger, Rolf; Spichiger-Keller, Ursula E.

    2006-01-01

    Novel nanostructured materials, such as aluminum oxide (AlOOH), silicon oxide (SiO 2 ) or zirconium oxide (ZrO 2 ) embedded into PVA, were investigated as potential matrices to incorporate organometallic compounds (OMCs) for the development of optical oxygen-sensitive sensors which make use of the principle of luminescence quenching. In order to assess the benefits and drawbacks of the nanoporous material, the luminescence quantum yield and the Stern-Volmer constants were investigated and compared with the values shown for the same OMCs solubilized in polymer films (polystyrene). Referred to polymer films, the incorporation of the dyes into nanoporous membranes increased the Stern-Volmer constant by more than a factor of 100. Their response time was less than 1 s and the optode membranes were stable at room temperature for at least 9 months. Sterilization by autoclavation and gamma irradiation resulted in a marginal loss in activity. The photostability and sterilizability of the oxygen-sensitive membranes and the performance of the optodes with respect to of different types of metal oxides are discussed in the paper, as well as the influence of the total pore volume (TPV), the pore diameter (PD), the transparency of the film and the geometry of the pores. The OMCs used in this work were: ETH T -3003 (tris(4,7-bis(4-octylphenyl)-1,10-phenanthroline) ruthenium(II)), N-926 (bis(2-phenylpyridinyl)-N 4 ,N 4 ,N 4 ',N 4 '-tetramethyl-(4,4'-diamine-2,2'-bipyridine) iridium(III) chlorate), N-833 (tetrabutylammonium bis(isothiocyanate) bis(2-phenylpyridinyl)-iridium(III)) and N-837 (tetrabutylammonium bis(cyanate) bis(2-phenylpyridinyl)-iridium(III))

  5. Single molecules and single nanoparticles as windows to the nanoscale

    Caldarola, Martín; Orrit, Michel

    2018-05-01

    Since the first optical detection of single molecules, they have been used as nanometersized optical sensors to explore the physical properties of materials and light-matter interaction at the nanoscale. Understanding nanoscale properties of materials is fundamental for the development of new technology that requires precise control of atoms and molecules when the quantum nature of matter cannot be ignored. In the following lines, we illustrate this journey into nanoscience with some experiments from our group.

  6. A fibre optic oxygen sensor that detects rapid PO2 changes under simulated conditions of cyclical atelectasis in vitro.

    Formenti, Federico; Chen, Rongsheng; McPeak, Hanne; Matejovic, Martin; Farmery, Andrew D; Hahn, Clive E W

    2014-01-15

    Two challenges in the management of Acute Respiratory Distress Syndrome are the difficulty in diagnosing cyclical atelectasis, and in individualising mechanical ventilation therapy in real-time. Commercial optical oxygen sensors can detect [Formula: see text] oscillations associated with cyclical atelectasis, but are not accurate at saturation levels below 90%, and contain a toxic fluorophore. We present a computer-controlled test rig, together with an in-house constructed ultra-rapid sensor to test the limitations of these sensors when exposed to rapidly changing [Formula: see text] in blood in vitro. We tested the sensors' responses to simulated respiratory rates between 10 and 60 breaths per minute. Our sensor was able to detect the whole amplitude of the imposed [Formula: see text] oscillations, even at the highest respiratory rate. We also examined our sensor's resistance to clot formation by continuous in vivo deployment in non-heparinised flowing animal blood for 24h, after which no adsorption of organic material on the sensor's surface was detectable by scanning electron microscopy. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  7. Oxygen sensor equipped engine operation on methanol/gasoline blends and phase separation problems

    Last, A J; Lawson, A; Simmons, E W; Mackay, D; Tsang, M; Maund, G B

    1980-01-01

    A study was made to address problems related to Canadian utilization of methanol/gasoline blends. These problems are: (1) cold weather operation; (2) water sensitivity to phase separation in winter; (3) vehicle compatibility: fuel/air ratio control, flexibility for vehicle movement outside of areas where methanol might be available. Specifically, the operation of the HydroShear (an in-line hydraulic emulsifier) on the two separated phases of a methanol/gasoline/water blend was examined. Fuel maps, by engine dynamometer testing, were generated using methanol/gasoline blends containing 15% to 65% methanol. The capability of an oxygen sensor, located in the exhaust system, to control the fuel/air ratio was found to be adequate within the 15% to 65% methanol/gasoline blends. A fuel injected Volvo 244DL with lambda-sond emission control and a carburetted Chevrolet Monza with 3-way catalyst closed loop feedback emission control system were the two engines selected for this study.

  8. Design parameters for voltage-controllable directed assembly of single nanoparticles

    Porter, Benjamin F.; Abelmann, Leon; Bhaskaran, Harish

    2013-01-01

    Techniques to reliably pick-and-place single nanoparticles into functional assemblies are required to incorporate exotic nanoparticles into standard electronic circuits. In this paper we explore the use of electric fields to drive and direct the assembly process, which has the advantage of being

  9. Crossed Optical Fiber Sensor Arrays for High-Spatial-Resolution Sensing: Application to Dissolved Oxygen Concentration Measurements

    M. Veronica Rigo

    2012-01-01

    Full Text Available Optical fiber sensors using luminescent probes located along an optical fiber in the cladding of this fiber are of great interest for monitoring physical and chemical properties in their environment. The interrogation of a luminophore with a short laser pulse propagating through the fiber core allows for the measurement of the location of these luminophores. To increase the spatial resolution of such a measurements and to measure multiple analytes and properties in a confined space, a crossed optical fiber sensing platform can be employed. Here we describe the application of this platform to measuring the concentration of dissolved oxygen. The sensor is based on luminescence quenching of a ruthenium complex immobilized in a highly crosslinked film and covalently attached to the optical fibers. Both luminescence-intensity and luminescence-lifetime changes of the sensor molecules in response to changes in the concentration of oxygen dissolved in water are reported. For luminescence-intensity measurements, a second adjacent sensor region is employed as reference to account for laser pulse energy fluctuations. Enhanced quenching response in water is demonstrated by the use of organically modified poly(ethylene glycol precursors, which increase the hydrophobicity of the film surface.

  10. Study and Development of a Fluorescence Based Sensor System for Monitoring Oxygen in Wine Production: The WOW Project.

    Trivellin, Nicola; Barbisan, Diego; Badocco, Denis; Pastore, Paolo; Meneghesso, Gaudenzio; Meneghini, Matteo; Zanoni, Enrico; Belgioioso, Giuseppe; Cenedese, Angelo

    2018-04-07

    The importance of oxygen in the winemaking process is widely known, as it affects the chemical aspects and therefore the organoleptic characteristics of the final product. Hence, it is evident the usefulness of a continuous and real-time measurements of the levels of oxygen in the various stages of the winemaking process, both for monitoring and for control. The WOW project (Deployment of WSAN technology for monitoring Oxygen in Wine products) has focused on the design and the development of an innovative device for monitoring the oxygen levels in wine. This system is based on the use of an optical fiber to measure the luminescent lifetime variation of a reference metal/porphyrin complex, which decays in presence of oxygen. The developed technology results in a high sensitivity and low cost sensor head that can be employed for measuring the dissolved oxygen levels at several points inside a wine fermentation or aging tank. This system can be complemented with dynamic modeling techniques to provide predictive behavior of the nutrient evolution in space and time given few sampled measuring points, for both process monitoring and control purposes. The experimental validation of the technology has been first performed in a controlled laboratory setup to attain calibration and study sensitivity with respect to different photo-luminescent compounds and alcoholic or non-alcoholic solutions, and then in an actual case study during a measurement campaign at a renown Italian winery.

  11. Study and Development of a Fluorescence Based Sensor System for Monitoring Oxygen in Wine Production: The WOW Project

    Trivellin, Nicola; Barbisan, Diego; Badocco, Denis; Pastore, Paolo; Meneghini, Matteo; Zanoni, Enrico; Belgioioso, Giuseppe

    2018-01-01

    The importance of oxygen in the winemaking process is widely known, as it affects the chemical aspects and therefore the organoleptic characteristics of the final product. Hence, it is evident the usefulness of a continuous and real-time measurements of the levels of oxygen in the various stages of the winemaking process, both for monitoring and for control. The WOW project (Deployment of WSAN technology for monitoring Oxygen in Wine products) has focused on the design and the development of an innovative device for monitoring the oxygen levels in wine. This system is based on the use of an optical fiber to measure the luminescent lifetime variation of a reference metal/porphyrin complex, which decays in presence of oxygen. The developed technology results in a high sensitivity and low cost sensor head that can be employed for measuring the dissolved oxygen levels at several points inside a wine fermentation or aging tank. This system can be complemented with dynamic modeling techniques to provide predictive behavior of the nutrient evolution in space and time given few sampled measuring points, for both process monitoring and control purposes. The experimental validation of the technology has been first performed in a controlled laboratory setup to attain calibration and study sensitivity with respect to different photo-luminescent compounds and alcoholic or non-alcoholic solutions, and then in an actual case study during a measurement campaign at a renown Italian winery. PMID:29642468

  12. The oxygen reactivity index and its relation to sensor technology in patients with severe brain lesions.

    Dengler, Julius; Frenzel, Christin; Vajkoczy, Peter; Horn, Peter; Wolf, Stefan

    2013-08-01

    The oxygen reactivity index (ORx) has been introduced to assess the status of cerebral autoregulation after traumatic brain injury (TBI) or subarachnoid hemorrhage (SAH). Currently, there is some controversy about whether the ORx depends on the type of PbrO2-sensor technology used for its calculation. To examine if the probe technology does matter, we compared the ORx and the resulting optimal cerebral perfusion pressures (CPPopt) of simultaneously implanted Licox (CC1.SB, Integra Neuroscience, France) and Neurovent-PTO (Raumedic, Germany) probes in patients after aneurysmal SAH or severe TBI. Licox and Raumedic probes were implanted side by side in 11 patients after TBI or SAH. ORx and CPPopt were recorded continuously. The equivalence of both probes was examined using Bland-Altman analyses. The mean difference in ORx was 0.1, with Licox producing higher values. The limits of agreement regarding ORx ranged from -0.6 to +0.7. When both probes' ORx values were compared in each patient, no specific pattern in their relationship was seen. The mean difference in CPPopt was 0 mmHg with limits of agreement between -16.5 and +16.4 mmHg. Owing to the rather limited number of patients, we view the results of this study as preliminary. The main result is that Licox and Raumedic showed consistent differences in ORx and CPPopt. Therefore, ORx values of both probes cannot be interchanged and should not be viewed as equivalent. This should be taken into consideration when discussing ORx data generated by different PbrO2 probe types.

  13. An Oxidase-Based Electrochemical Fluidic Sensor with High-Sensitivity and Low-Interference by On-Chip Oxygen Manipulation

    Chang-Soo Kim

    2012-06-01

    Full Text Available Utilizing a simple fluidic structure, we demonstrate the improved performance of oxidase-based enzymatic biosensors. Electrolysis of water is utilized to generate bubbles to manipulate the oxygen microenvironment close to the biosensor in a fluidic channel. For the proper enzyme reactions to occur, a simple mechanical procedure of manipulating bubbles was developed to maximize the oxygen level while minimizing the pH change after electrolysis. The sensors show improved sensitivities based on the oxygen dependency of enzyme reaction. In addition, this oxygen-rich operation minimizes the ratio of electrochemical interference signal by ascorbic acid during sensor operation (i.e., amperometric detection of hydrogen peroxide. Although creatinine sensors have been used as the model system in this study, this method is applicable to many other biosensors that can use oxidase enzymes (e.g., glucose, alcohol, phenol, etc. to implement a viable component for in-line fluidic sensor systems.

  14. Multiple approaches for enhancing all-organic electronics photoluminescent sensors: Simultaneous oxygen and pH monitoring

    Liu, Rui; Xiao, Teng; Cui, Weipan; Shinar, Joseph; Shinar, Ruth

    2013-01-01

    Graphical abstract: -- Highlights: •Novel simply-fabricated all-organic electronics pH and oxygen optical monitor. •Excitation sources: directionally emitting, narrowed multicolor microcavity OLEDs. •Photodetectors: small molecule- or polymer-based with selective spectral responses. •Sensor film: structured high molecular weight polystyrene:polyethylene glycol blend. •×1.9 sensitivity enhancement and ×2.7 increase in the photoluminescence for oxygen. -- Abstract: Key issues in using organic light emitting diodes (OLEDs) as excitation sources in structurally integrated photoluminescence (PL)-based sensors are the low forward light outcoupling, the OLEDs’ broad electroluminescence (EL) bands, and the long-lived remnant EL that follows an EL pulse. The outcoupling issue limits the detection sensitivity (S) as only ∼20% of the light generated within standard OLEDs can be forward outcoupled and used for sensor probe excitation. The EL broad band interferes with the analyte-sensitive PL, leading to a background that reduces S and dynamic range. In particular, these issues hinder designing compact sensors, potentially miniaturizable, that are devoid of optical filters and couplers. We address these shortcomings by introducing easy-to-employ multiple approaches for outcoupling improvement, PL enhancement, and background EL reduction leading to novel, compact all-organic device architectures demonstrated for simultaneous monitoring of oxygen and pH. The sensor comprises simply-fabricated, directionally-emitting, narrower-band, multicolor microcavity OLED excitation and small molecule- and polymer-based organic photodetectors (OPDs) with a more selective spectral response. Additionally, S and PL intensity for oxygen are enhanced by using polystyrene (PS):polyethylene glycol (PEG) blends as the sensing film matrix. By utilizing higher molecular weight PS, the ratio τ 0 /τ 100 (PL decay time τ at 0% O 2 /τ at 100% O 2 ) that is often used to express S

  15. The Role of Oxygen Sensors, Hydroxylases, and HIF in Cardiac Function and Disease

    W. H. Davin Townley-Tilson

    2015-01-01

    Full Text Available Ischemic heart disease is the leading cause of death worldwide. Oxygen-sensing proteins are critical components of the physiological response to hypoxia and reperfusion injury, but the role of oxygen and oxygen-mediated effects is complex in that they can be cardioprotective or deleterious to the cardiac tissue. Over 200 oxygen-sensing proteins mediate the effects of oxygen tension and use oxygen as a substrate for posttranslational modification of other proteins. Hydroxylases are an essential component of these oxygen-sensing proteins. While a major role of hydroxylases is regulating the transcription factor HIF, we investigate the increasing scope of hydroxylase substrates. This review discusses the importance of oxygen-mediated effects in the heart as well as how the field of oxygen-sensing proteins is expanding, providing a more complete picture into how these enzymes play a multifaceted role in cardiac function and disease. We also review how oxygen-sensing proteins and hydroxylase function could prove to be invaluable in drug design and therapeutic targets for heart disease.

  16. Single-nanoparticle detection with slot-mode photonic crystal cavities

    Wang, Cheng; Kita, Shota; Lončar, Marko, E-mail: loncar@seas.harvard.edu [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Quan, Qimin [Rowland Institute at Harvard University, Cambridge, Massachusetts 02142 (United States); Li, Yihang [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Department of Electronic Engineering, Tsinghua University, Beijing 100084 (China)

    2015-06-29

    Optical cavities that are capable for detecting single nanoparticles could lead to great progress in early stage disease diagnostics and the study of biological interactions on the single-molecule level. In particular, photonic crystal (PhC) cavities are excellent platforms for label-free single-nanoparticle detection, owing to their high quality (Q) factors and wavelength-scale modal volumes. Here, we demonstrate the design and fabrication of a high-Q (>10{sup 4}) slot-mode PhC nanobeam cavity, which is able to strongly confine light in the slotted regions. The enhanced light-matter interaction results in an order of magnitude improvement in both refractive index sensitivity (439 nm/RIU) and single-nanoparticle sensitivity compared with conventional dielectric-mode PhC cavities. Detection of single polystyrene nanoparticles with radii of 20 nm and 30 nm is demonstrated in aqueous environments (D{sub 2}O), without additional laser and temperature stabilization techniques.

  17. Enhanced response of microbial fuel cell using sulfonated poly ether ether ketone membrane as a biochemical oxygen demand sensor

    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.

  18. Multiple approaches for enhancing all-organic electronics photoluminescent sensors: simultaneous oxygen and pH monitoring.

    Liu, Rui; Xiao, Teng; Cui, Weipan; Shinar, Joseph; Shinar, Ruth

    2013-05-17

    Key issues in using organic light emitting diodes (OLEDs) as excitation sources in structurally integrated photoluminescence (PL)-based sensors are the low forward light outcoupling, the OLEDs' broad electroluminescence (EL) bands, and the long-lived remnant EL that follows an EL pulse. The outcoupling issue limits the detection sensitivity (S) as only ~20% of the light generated within standard OLEDs can be forward outcoupled and used for sensor probe excitation. The EL broad band interferes with the analyte-sensitive PL, leading to a background that reduces S and dynamic range. In particular, these issues hinder designing compact sensors, potentially miniaturizable, that are devoid of optical filters and couplers. We address these shortcomings by introducing easy-to-employ multiple approaches for outcoupling improvement, PL enhancement, and background EL reduction leading to novel, compact all-organic device architectures demonstrated for simultaneous monitoring of oxygen and pH. The sensor comprises simply-fabricated, directionally-emitting, narrower-band, multicolor microcavity OLED excitation and small molecule- and polymer-based organic photodetectors (OPDs) with a more selective spectral response. Additionally, S and PL intensity for oxygen are enhanced by using polystyrene (PS):polyethylene glycol (PEG) blends as the sensing film matrix. By utilizing higher molecular weight PS, the ratio τ0/τ100 (PL decay time τ at 0% O2/τ at 100% O2) that is often used to express S increases ×1.9 to 20.7 relative to the lower molecular weight PS, where this ratio is 11.0. This increase reduces to ×1.7 when the PEG is added (τ0/τ100=18.2), but the latter results in an increase ×2.7 in the PL intensity. The sensor's response time is <10s in all cases. The microporous structure of these blended films, with PEG decorating PS pores, serves a dual purpose. It results in light scattering that reduces the EL that is waveguided in the substrate of the OLEDs and

  19. Multiple approaches for enhancing all-organic electronics photoluminescent sensors: Simultaneous oxygen and pH monitoring

    Liu, Rui; Xiao, Teng; Cui, Weipan [Ames Laboratory-USDOE and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Shinar, Joseph, E-mail: jshinar@iastate.edu [Ames Laboratory-USDOE and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Shinar, Ruth, E-mail: rshinar@iastate.edu [Microelectronics Research Center and Department of Electrical and Computer Engineering, Iowa State University, Ames, IA 50011 (United States)

    2013-05-17

    Graphical abstract: -- Highlights: •Novel simply-fabricated all-organic electronics pH and oxygen optical monitor. •Excitation sources: directionally emitting, narrowed multicolor microcavity OLEDs. •Photodetectors: small molecule- or polymer-based with selective spectral responses. •Sensor film: structured high molecular weight polystyrene:polyethylene glycol blend. •×1.9 sensitivity enhancement and ×2.7 increase in the photoluminescence for oxygen. -- Abstract: Key issues in using organic light emitting diodes (OLEDs) as excitation sources in structurally integrated photoluminescence (PL)-based sensors are the low forward light outcoupling, the OLEDs’ broad electroluminescence (EL) bands, and the long-lived remnant EL that follows an EL pulse. The outcoupling issue limits the detection sensitivity (S) as only ∼20% of the light generated within standard OLEDs can be forward outcoupled and used for sensor probe excitation. The EL broad band interferes with the analyte-sensitive PL, leading to a background that reduces S and dynamic range. In particular, these issues hinder designing compact sensors, potentially miniaturizable, that are devoid of optical filters and couplers. We address these shortcomings by introducing easy-to-employ multiple approaches for outcoupling improvement, PL enhancement, and background EL reduction leading to novel, compact all-organic device architectures demonstrated for simultaneous monitoring of oxygen and pH. The sensor comprises simply-fabricated, directionally-emitting, narrower-band, multicolor microcavity OLED excitation and small molecule- and polymer-based organic photodetectors (OPDs) with a more selective spectral response. Additionally, S and PL intensity for oxygen are enhanced by using polystyrene (PS):polyethylene glycol (PEG) blends as the sensing film matrix. By utilizing higher molecular weight PS, the ratio τ{sub 0}/τ{sub 100} (PL decay time τ at 0% O{sub 2}/τ at 100% O{sub 2}) that is often used

  20. Microencapsulated 3-dimensional sensor for the measurement of oxygen in single isolated pancreatic islets.

    Wanyu Chen

    Full Text Available Oxygen consumption reflects multiple processes in pancreatic islets including mechanisms contributing to insulin secretion, oxidative stress and viability, providing an important readout in studies of islet function, islet viability and drug testing. Due to the scarcity, heterogeneity, and intrinsic kinetic properties of individual islets, it would be of great benefit to detect oxygen consumption by single islets. We present a novel method we have developed to image oxygen in single islets.Using a microfluidics system, individual islets and a fluorescent oxygen-sensitive dye were encased within a thin alginate polymer layer. Insulin secretion by the encapsulated islets was normal. Fluorescent signal from the encased dye, detected using a standard inverted fluorescence microscope and digital camera, was stable and proportional to the amount of oxygen in the media. When integrated into a perifusion system, the sensing system detected changes in response to metabolic substrates, mitochondrial poisons, and induced-oscillations. Glucose responses averaged 30.1±7.1% of the response to a metabolic inhibitor (cyanide, increases were observed in all cases (n = 6, and the system was able to resolve changes in oxygen consumption that had a period greater than 0.5 minutes. The sensing system operated similarly from 2-48 hours following encapsulation, and viability and function of the islets were not significantly affected by the encapsulation process.An oxygen-dependent dye situated around and within a pancreatic islet encapsulated by a thin layer of alginate was sensitive to changes in oxygen consumption, and was not harmful to the function or viability of islets over the course of two days. The microcapsule-based sensing method is particularly suited to assessing the effects of compounds (dose responses and time courses and chronic changes occurring over the course of days. The approach should be applicable to other cell types and dyes sensitive to other

  1. Microencapsulated 3-Dimensional Sensor for the Measurement of Oxygen in Single Isolated Pancreatic Islets

    Khalil, Gamal; Sweet, Ian R.; Shen, Amy Q.

    2012-01-01

    Background Oxygen consumption reflects multiple processes in pancreatic islets including mechanisms contributing to insulin secretion, oxidative stress and viability, providing an important readout in studies of islet function, islet viability and drug testing. Due to the scarcity, heterogeneity, and intrinsic kinetic properties of individual islets, it would be of great benefit to detect oxygen consumption by single islets. We present a novel method we have developed to image oxygen in single islets. Methodology/Principal Findings Using a microfluidics system, individual islets and a fluorescent oxygen-sensitive dye were encased within a thin alginate polymer layer. Insulin secretion by the encapsulated islets was normal. Fluorescent signal from the encased dye, detected using a standard inverted fluorescence microscope and digital camera, was stable and proportional to the amount of oxygen in the media. When integrated into a perifusion system, the sensing system detected changes in response to metabolic substrates, mitochondrial poisons, and induced-oscillations. Glucose responses averaged 30.1±7.1% of the response to a metabolic inhibitor (cyanide), increases were observed in all cases (n = 6), and the system was able to resolve changes in oxygen consumption that had a period greater than 0.5 minutes. The sensing system operated similarly from 2–48 hours following encapsulation, and viability and function of the islets were not significantly affected by the encapsulation process. Conclusions/Significance An oxygen-dependent dye situated around and within a pancreatic islet encapsulated by a thin layer of alginate was sensitive to changes in oxygen consumption, and was not harmful to the function or viability of islets over the course of two days. The microcapsule-based sensing method is particularly suited to assessing the effects of compounds (dose responses and time courses) and chronic changes occurring over the course of days. The approach should be

  2. A highly sensitive amperometric sensor for oxygen based on iron(II) tetrasulfonated phthalocyanine and iron(III) tetra-(N-methyl-pyridyl)-porphyrin multilayers

    Duarte, Juliana C.; Luz, Rita C.S.; Damos, Flavio S.; Tanaka, Auro A.; Kubota, Lauro T.

    2008-01-01

    The development of a highly sensitive sensor for oxygen is proposed using a glassy carbon (GC) electrode modified with alternated layers of iron(II) tetrasulfonated phthalocyanine (FeTsPc) and iron(III) tetra-(N-methyl-pyridyl)-porphyrin (FeT4MPyP). The modified electrode showed excellent catalytic activity for the oxygen reduction. The reduction potential of the oxygen was shifted about 330 mV toward less negative values with this modified electrode, presenting a peak current much higher than those observed on a bare GC electrode. Cyclic voltammetry and rotating disk electrode (RDE) experiments indicated that the oxygen reduction reaction involves 4 electrons with a heterogenous rate constant (k obs ) of 3 x 10 5 mol -1 L s -1 . A linear response range from 0.2 up to 6.4 mg L -1 , with a sensitivity of 4.12 μA L mg -1 (or 20.65 μA cm -2 L mg -1 ) and a detection limit of 0.06 mg L -1 were obtained with this sensor. The repeatability of the proposed sensor, evaluated in terms of relative standard deviation (R.S.D.) was 2.0% for 10 measurements of a solution of 6.4 mg L -1 oxygen. The sensor was applied to determine oxygen in pond and tap water samples showing to be a promising tool for this purpose

  3. A Micro Oxygen Sensor Based on a Nano Sol-Gel TiO2 Thin Film

    Hairong Wang

    2014-09-01

    Full Text Available An oxygen gas microsensor based on nanostructured sol-gel TiO2 thin films with a buried Pd layer was developed on a silicon substrate. The nanostructured titania thin films for O2 sensors were prepared by the sol-gel process and became anatase after heat treatment. A sandwich TiO2 square board with an area of 350 μm × 350 μm was defined by both wet etching and dry etching processes and the wet one was applied in the final process due to its advantages of easy control for the final structure. A pair of 150 nm Pt micro interdigitated electrodes with 50 nm Ti buffer layer was fabricated on the board by a lift-off process. The sensor chip was tested in a furnace with changing the O2 concentration from 1.0% to 20% by monitoring its electrical resistance. Results showed that after several testing cycles the sensor’s output becomes stable, and its sensitivity is 0.054 with deviation 2.65 × 10−4 and hysteresis is 8.5%. Due to its simple fabrication process, the sensor has potential for application in environmental monitoring, where lower power consumption and small size are required.

  4. A Macroporous TiO2 Oxygen Sensor Fabricated Using Anodic Aluminium Oxide as an Etching Mask

    Sheng-Po Wu

    2010-01-01

    Full Text Available An innovative fabrication method to produce a macroporous Si surface by employing an anodic aluminium oxide (AAO nanopore array layer as an etching template is presented. Combining AAO with a reactive ion etching (RIE processes, a homogeneous and macroporous silicon surface can be effectively configured by modulating AAO process parameters and alumina film thickness, thus hopefully replacing conventional photolithography and electrochemical etch methods. The hybrid process integration is considered fully CMOS compatible thanks to the low-temperature AAO and CMOS processes. The gas-sensing characteristics of 50 nm TiO2 nanofilms deposited on the macroporous surface are compared with those of conventional plain (or non-porous nanofilms to verify reduced response noise and improved sensitivity as a result of their macroporosity. Our experimental results reveal that macroporous geometry of the TiO2 chemoresistive gas sensor demonstrates 2-fold higher (~33% improved sensitivity than a non-porous sensor at different levels of oxygen exposure. In addition, the macroporous device exhibits excellent discrimination capability and significantly lessened response noise at 500 °C. Experimental results indicate that the hybrid process of such miniature and macroporous devices are compatible as well as applicable to integrated next generation bio-chemical sensors.

  5. Injectable LiNc-BuO loaded microspheres as in vivo EPR oxygen sensors after co-implantation with tumor cells.

    Frank, Juliane; Gündel, Daniel; Drescher, Simon; Thews, Oliver; Mäder, Karsten

    2015-12-01

    Electron paramagnetic resonance (EPR) oximetry is a technique which allows accurate and repeatable oxygen measurements. We encapsulated a highly oxygen sensitive particulate EPR spin probe into microparticles to improve its dispersibility and, hence, facilitate the administration. These biocompatible, non-toxic microspheres contained 5-10 % (w/w) spin probe and had an oxygen sensitivity of 0.60 ± 0.01 µT/mmHg. To evaluate the performance of the microparticles as oxygen sensors, they were co-implanted with syngeneic tumor cells in 2 different rat strains. Thus, tissue injury was avoided and the microparticles were distributed all over the tumor tissue. Dynamic changes of the intratumoral oxygen partial pressure during inhalation of 8 %, 21 %, or 100 % oxygen were monitored in vivo by EPR spectroscopy and quantified. Values were verified in vivo by invasive fluorometric measurements using Oxylite probes and ex vivo by pimonidazole adduct accumulation. There were no hints that the tumor physiology or tissue oxygenation had been altered by the microparticles. Hence, these microprobes offer great potential as oxygen sensors in preclinical research, not only for EPR spectroscopy but also for EPR imaging. For instance, the assessment of tissue oxygenation during therapeutic interventions might help understanding pathophysiological processes and lead to an individualized treatment planning or the use of formulations with hypoxia triggered release of active agents. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Improvement in the Sensitivity of PbO Doped Tin Oxide Thick Film Gas Sensor by RF and Microwave Oxygen Plasma Treatment

    J. K. SRIVASTAVA

    2010-07-01

    Full Text Available In the present work efforts have been made to analyze the effect of oxygen plasma and PbO doping on the sensitivity of SnO2-based thick film gas sensor for methanol, propanol and acetone. The effect of substrate temperature on the response of dual frequency (RF and microwave plasma treated thick film sensor array has also been studied. To achieve this, three sensor arrays (each with four tin oxide sensors doped with different (1 %, 2 %, 3 % and 4 % PbO concentrations were fabricated by thick film technology and then treated with oxygen plasma for various durations (5 min, 10 min. and 15 min.. The plasma treated sensors were found to possess appreciably high sensitivity at room temperature in comparison to untreated sensor. The sensitivity showed the increasing trend with plasma exposure time and 15 minutes exposure time was found to be most suitable as the sensitivity of the plasma treated sensors for this duration were high towards all the chosen vapors with maximum (97 % value for propanol. The sensitivity of the sensors were found to be increasing gradually as PbO concentration was varied from 1- 4%.

  7. The Determination of the Percent of Oxygen in Air Using a Gas Pressure Sensor

    Gordon, James; Chancey, Katherine

    2005-01-01

    The experiment of determination of the percent of oxygen in air is performed in a general chemistry laboratory in which students compare the results calculated from the pressure measurements obtained with the calculator-based systems to those obtained in a water-measurement method. This experiment allows students to explore a fundamental reaction…

  8. Detection and characterization of single nanoparticles by interferometric phase modulated ellipsometry

    Barroso, F.; Bosch, S.; Tort, N.; Arteaga, O. [Universitat de Barcelona, IN2UB, Dep. Fisica Aplicada i Optica, c/Marti i Franques 1, 08028 (Spain); Sancho-Parramon, J. [Rudjer Boskovic Institute, Bijenicka c. 54, Zagreb 10002 (Croatia); Jover, E.; Bertran, E. [Universitat de Barcelona, IN2UB, Dep. Fisica Aplicada i Optica, c/Marti i Franques 1, 08028 (Spain); Canillas, A., E-mail: acanillas@ub.ed [Universitat de Barcelona, IN2UB, Dep. Fisica Aplicada i Optica, c/Marti i Franques 1, 08028 (Spain)

    2011-02-28

    We introduce a new measurement system called Nanopolar interferometer devoted to monitor and characterize single nanoparticles which is based on the interferometric phase modulated ellipsometry technique. The system collects the backscattered light by the particles in the solid angle subtended by a microscope objective and then analyses its frequency components. The results for the detection of 2 {mu}m and 50 nm particles are explained in terms of a cross polarization effect of the polarization vectors when the beam converts from divergent to parallel in the microscope objective. This explanation is supported with the results of the optical modelling using the exact Mie theory for the light scattered by the particles.

  9. Detection and characterization of single nanoparticles by interferometric phase modulated ellipsometry

    Barroso, F.; Bosch, S.; Tort, N.; Arteaga, O.; Sancho-Parramon, J.; Jover, E.; Bertran, E.; Canillas, A.

    2011-01-01

    We introduce a new measurement system called Nanopolar interferometer devoted to monitor and characterize single nanoparticles which is based on the interferometric phase modulated ellipsometry technique. The system collects the backscattered light by the particles in the solid angle subtended by a microscope objective and then analyses its frequency components. The results for the detection of 2 μm and 50 nm particles are explained in terms of a cross polarization effect of the polarization vectors when the beam converts from divergent to parallel in the microscope objective. This explanation is supported with the results of the optical modelling using the exact Mie theory for the light scattered by the particles.

  10. Effect of oxygen and hydrogen on the optical and electrical characteristics of porous silicon. Towards sensor applications

    Green, S.

    2000-02-01

    The effect of adsorbed oxygen and hydrogen gas on porous silicon has been investigated using two different techniques, viz. optical and electrical. The photoluminescence quenching by oxygen and hydrogen was found to be reversible with a response time of the order of 3000 s. Unlike any reported porous silicon gas quenching systems, both the extent and rate of quenching were found to be a function of photoluminescence wavelength. The quenching is attributed to charge transfer from the conduction band of porous silicon to the lowest unoccupied molecular orbital of oxygen and hydrogen, respectively. Surface conductance measurements (aluminium contacts) show that the principal charge transfer process is via tunnelling, with some conduction through the underlying bulk p-type silicon layer. Symmetrical current-voltage plots were obtained for this system which were attributed to pinning of the aluminium-porous silicon Fermi level at mid-gap by the high surface trap density. An approximate doubling of the aluminium electrode separation was found to reduce approximately fourfold the initial rate of increase in surface conductance on adsorption of oxygen at a pressure of 10 torr. To the best of the author's knowledge this is the first time that such an effect has been reported in a room temperature solid state gas sensor. Gas sensitivity measurements using surface contacts show a logarithmic response to the concentration of oxygen up to a pressure of 100 torr with a rapid response, of 300 s. A 39% increase in surface conductance occurs on exposure of the device to 100 torr of oxygen. The surface conductance of the device decreases by 34% on exposure to one atmosphere of hydrogen with a response time of the order 2000 s. Transverse conductance (DC) measurements show that Au/PS/p-Si/Al..Ag devices behave like a field-dependent diode. An admittance spectroscopy technique has been applied to porous silicon for the first time to calculate g 0 , the trap density at the Fermi level

  11. Role of distal arginine in early sensing intermediates in the heme domain of the oxygen sensor FixL.

    Jasaitis, Audrius; Hola, Klara; Bouzhir-Sima, Latifa; Lambry, Jean-Christophe; Balland, Veronique; Vos, Marten H; Liebl, Ursula

    2006-05-16

    FixL is a bacterial heme-based oxygen sensor, in which release of oxygen from the sensing PAS domain leads to activation of an associated kinase domain. Static structural studies have suggested an important role of the conserved residue arginine 220 in signal transmission at the level of the heme domain. To assess the role of this residue in the dynamics and properties of the initial intermediates in ligand release, we have investigated the effects of R220X (X = I, Q, E, H, or A) mutations in the FixLH heme domain on the dynamics and spectral properties of the heme upon photolysis of O(2), NO, and CO using femtosecond transient absorption spectroscopy. Comparison of transient spectra for CO and NO dissociation with steady-state spectra indicated less strain on the heme in the ligand dissociation species for all mutants compared to the wild type (WT). For CO and NO, the kinetics were similar to those of the wild type, with the exception of (1) a relatively low yield of picosecond NO rebinding to R220A, presumably related to the increase in the free volume of the heme pocket, and (2) substantial pH-dependent picosecond to nanosecond rebinding of CO to R220H, related to formation of a hydrogen bond between CO and histidine 220. Upon excitation of the complex bound with the physiological sensor ligand O(2), a 5-8 ps decay phase and a nondecaying (>4 ns) phase were observed for WT and all mutants. The strong distortion of the spectrum associated with the decay phase in WT is substantially diminished in all mutant proteins, indicating an R220-induced role of the heme in the primary intermediate in signal transmission. Furthermore, the yield of dissociated oxygen after this phase ( approximately 10% in WT) is increased in all mutants, up to almost unity in R220A, indicating a key role of R220 in caging the oxygen near the heme through hydrogen bonding. Molecular dynamics simulations corroborate these findings and suggest motions of O(2) and arginine 220 away from the heme

  12. A Lab Assembled Microcontroller-Based Sensor Module for Continuous Oxygen Measurement in Portable Hypoxia Chambers

    Mathupala, Saroj P.; Kiousis, Sam; Szerlip, Nicholas J.

    2016-01-01

    Background Hypoxia-based cell culture experiments are routine and essential components of in vitro cancer research. Most laboratories use low-cost portable modular chambers to achieve hypoxic conditions for cell cultures, where the sealed chambers are purged with a gas mixture of preset O2 concentration. Studies are conducted under the assumption that hypoxia remains unaltered throughout the 48 to 72 hour duration of such experiments. Since these chambers lack any sensor or detection system t...

  13. Single-Nanoparticle Photoelectrochemistry at a Nanoparticulate TiO2 -Filmed Ultramicroelectrode.

    Peng, Yue-Yi; Ma, Hui; Ma, Wei; Long, Yi-Tao; Tian, He

    2018-03-26

    An ultrasensitive photoelectrochemical method for achieving real-time detection of single nanoparticle collision events is presented. Using a micrometer-thick nanoparticulate TiO 2 -filmed Au ultra-microelectrode (TiO 2 @Au UME), a sub-millisecond photocurrent transient was observed for an individual N719-tagged TiO 2 (N719@TiO 2 ) nanoparticle and is due to the instantaneous collision process. Owing to a trap-limited electron diffusion process as the rate-limiting step, a random three-dimensional diffusion model was developed to simulate electron transport dynamics in TiO 2 film. The combination of theoretical simulation and high-resolution photocurrent measurement allow electron-transfer information of a single N719@TiO 2 nanoparticle to be quantified at single-molecule accuracy and the electron diffusivity and the electron-collection efficiency of TiO 2 @Au UME to be estimated. This method provides a test for studies of photoinduced electron transfer at the single-nanoparticle level. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Sensors

    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...

  15. A multiplexed electronic architecture for opto-electronic patch sensor to effectively monitor heart rate and oxygen saturation

    Yan, Liangwen; Hu, Sijung; Alharbi, Samah; Blanos, Panagiotis

    2018-02-01

    To effectively capture human vital signs, a multi-wavelength optoelectronic patch sensor (MOEPS), together with a schematic architecture of electronics, was developed to overcome the drawbacks of present photoplethysmographic (PPG) sensors. To obtain a better performance of in vivo physiological measurement, the optimal illuminations, i.e., light emitting diodes (LEDs) in the MOEPS, whose wavelength is automatically adjusted to each specific subject, were selected to capture better PPG signals. A multiplexed electronic architecture has been well established to properly drive the MOEPS and effectively capture pulsatile waveforms at rest. The protocol was designed to investigate its performance with the participation of 11 healthy subjects aged between 18 and 30. The signals obtained from green (525nm) and orange (595nm) illuminations were used to extract heart rate (HR) and oxygen saturation (SpO2%). These results were compared with data, simultaneously acquired, from a commercial ECG and a pulse oximeter. Considering the difficulty for current devices to attain the SpO2%, a new computing method, to obtain the value of SpO2%, is proposed depended on the green and orange wavelength illuminations. The values of SpO2% between the MOEPS and the commercial Pulse Oximeter devics showed that the results were in good agreement. The values of HR showed close correlation between commercial devices and the MOEPS (HR: r1=0.994(Green); r2=0.992(Orange); r3=0.975(Red); r4=0.990(IR)).

  16. A Lab Assembled Microcontroller-Based Sensor Module for Continuous Oxygen Measurement in Portable Hypoxia Chambers

    Mathupala, Saroj P.; Kiousis, Sam; Szerlip, Nicholas J.

    2016-01-01

    Background Hypoxia-based cell culture experiments are routine and essential components of in vitro cancer research. Most laboratories use low-cost portable modular chambers to achieve hypoxic conditions for cell cultures, where the sealed chambers are purged with a gas mixture of preset O2 concentration. Studies are conducted under the assumption that hypoxia remains unaltered throughout the 48 to 72 hour duration of such experiments. Since these chambers lack any sensor or detection system to monitor gas-phase O2, the cell-based data tend to be non-uniform due to the ad hoc nature of the experimental setup. Methodology With the availability of low-cost open-source microcontroller-based electronic project kits, it is now possible for researchers to program these with easy-to-use software, link them to sensors, and place them in basic scientific apparatus to monitor and record experimental parameters. We report here the design and construction of a small-footprint kit for continuous measurement and recording of O2 concentration in modular hypoxia chambers. The low-cost assembly (US$135) consists of an Arduino-based microcontroller, data-logging freeware, and a factory pre-calibrated miniature O2 sensor. A small, intuitive software program was written by the authors to control the data input and output. The basic nature of the kit will enable any student in biology with minimal experience in hobby-electronics to assemble the system and edit the program parameters to suit individual experimental conditions. Results/Conclusions We show the kit’s utility and stability of data output via a series of hypoxia experiments. The studies also demonstrated the critical need to monitor and adjust gas-phase O2 concentration during hypoxia-based experiments to prevent experimental errors or failure due to partial loss of hypoxia. Thus, incorporating the sensor-microcontroller module to a portable hypoxia chamber provides a researcher a capability that was previously available

  17. A Lab Assembled Microcontroller-Based Sensor Module for Continuous Oxygen Measurement in Portable Hypoxia Chambers.

    Saroj P Mathupala

    Full Text Available Hypoxia-based cell culture experiments are routine and essential components of in vitro cancer research. Most laboratories use low-cost portable modular chambers to achieve hypoxic conditions for cell cultures, where the sealed chambers are purged with a gas mixture of preset O2 concentration. Studies are conducted under the assumption that hypoxia remains unaltered throughout the 48 to 72 hour duration of such experiments. Since these chambers lack any sensor or detection system to monitor gas-phase O2, the cell-based data tend to be non-uniform due to the ad hoc nature of the experimental setup.With the availability of low-cost open-source microcontroller-based electronic project kits, it is now possible for researchers to program these with easy-to-use software, link them to sensors, and place them in basic scientific apparatus to monitor and record experimental parameters. We report here the design and construction of a small-footprint kit for continuous measurement and recording of O2 concentration in modular hypoxia chambers. The low-cost assembly (US$135 consists of an Arduino-based microcontroller, data-logging freeware, and a factory pre-calibrated miniature O2 sensor. A small, intuitive software program was written by the authors to control the data input and output. The basic nature of the kit will enable any student in biology with minimal experience in hobby-electronics to assemble the system and edit the program parameters to suit individual experimental conditions.We show the kit's utility and stability of data output via a series of hypoxia experiments. The studies also demonstrated the critical need to monitor and adjust gas-phase O2 concentration during hypoxia-based experiments to prevent experimental errors or failure due to partial loss of hypoxia. Thus, incorporating the sensor-microcontroller module to a portable hypoxia chamber provides a researcher a capability that was previously available only to labs with access to

  18. A Lab Assembled Microcontroller-Based Sensor Module for Continuous Oxygen Measurement in Portable Hypoxia Chambers.

    Mathupala, Saroj P; Kiousis, Sam; Szerlip, Nicholas J

    2016-01-01

    Hypoxia-based cell culture experiments are routine and essential components of in vitro cancer research. Most laboratories use low-cost portable modular chambers to achieve hypoxic conditions for cell cultures, where the sealed chambers are purged with a gas mixture of preset O2 concentration. Studies are conducted under the assumption that hypoxia remains unaltered throughout the 48 to 72 hour duration of such experiments. Since these chambers lack any sensor or detection system to monitor gas-phase O2, the cell-based data tend to be non-uniform due to the ad hoc nature of the experimental setup. With the availability of low-cost open-source microcontroller-based electronic project kits, it is now possible for researchers to program these with easy-to-use software, link them to sensors, and place them in basic scientific apparatus to monitor and record experimental parameters. We report here the design and construction of a small-footprint kit for continuous measurement and recording of O2 concentration in modular hypoxia chambers. The low-cost assembly (US$135) consists of an Arduino-based microcontroller, data-logging freeware, and a factory pre-calibrated miniature O2 sensor. A small, intuitive software program was written by the authors to control the data input and output. The basic nature of the kit will enable any student in biology with minimal experience in hobby-electronics to assemble the system and edit the program parameters to suit individual experimental conditions. We show the kit's utility and stability of data output via a series of hypoxia experiments. The studies also demonstrated the critical need to monitor and adjust gas-phase O2 concentration during hypoxia-based experiments to prevent experimental errors or failure due to partial loss of hypoxia. Thus, incorporating the sensor-microcontroller module to a portable hypoxia chamber provides a researcher a capability that was previously available only to labs with access to sophisticated (and

  19. Low Power Resistive Oxygen Sensor Based on Sonochemical SrTi0.6Fe0.4O2.8 (STFO40

    Alisa Stratulat

    2015-07-01

    Full Text Available The current paper reports on a sonochemical synthesis method for manufacturing nanostructured (typical grain size of 50 nm SrTi0.6Fe0.4O2.8 (Sono-STFO40 powder. This powder is characterized using X ray-diffraction (XRD, Mössbauer spectroscopy and Scanning Electron Microscopy (SEM, and results are compared with commercially available SrTi0.4Fe0.6O2.8 (STFO60 powder. In order to manufacture resistive oxygen sensors, both Sono-STFO40 and STFO60 are deposited, by dip-pen nanolithography (DPN method, on an SOI (Silicon-on-Insulator micro-hotplate, employing a tungsten heater embedded within a dielectric membrane. Oxygen detection tests are performed in both dry (RH = 0% and humid (RH = 60% nitrogen atmosphere, varying oxygen concentrations between 1% and 16% (v/v, at a constant heater temperature of 650 °C. The oxygen sensor, based on the Sono-STFO40 sensing layer, shows good sensitivity, low power consumption (80 mW, and short response time (25 s. These performance are comparable to those exhibited by state-of-the-art O2 sensors based on STFO60, thus proving Sono-STFO40 to be a material suitable for oxygen detection in harsh environments.

  20. Arteriolar oxygen reactivity: where is the sensor and what is the mechanism of action?

    2016-01-01

    Abstract Arterioles in the peripheral microcirculation are exquisitely sensitive to changes in PO2 in their environment: increases in PO2 cause vasoconstriction while decreases in PO2 result in vasodilatation. However, the cell type that senses O2 (the O2 sensor) and the signalling pathway that couples changes in PO2 to changes in arteriolar tone (the mechanism of action) remain unclear. Many (but not all) ex vivo studies of isolated cannulated resistance arteries and large, first‐order arterioles support the hypothesis that these vessels are intrinsically sensitive to PO2 with the smooth muscle, endothelial cells, or red blood cells serving as the O2 sensor. However, in situ studies testing these hypotheses in downstream arterioles have failed to find evidence of intrinsic O2 sensitivity, and instead have supported the idea that extravascular cells sense O2. Similarly, ex vivo studies of isolated, cannulated resistance arteries and large first‐order arterioles support the hypotheses that O2‐dependent inhibition of production of vasodilator cyclooxygenase products or O2‐dependent destruction of nitric oxide mediates O2 reactivity of these upstream vessels. In contrast, most in vivo studies of downstream arterioles have disproved these hypotheses and instead have provided evidence supporting the idea that O2‐dependent production of vasoconstrictors mediates arteriolar O2 reactivity, with significant regional heterogeneity in the specific vasoconstrictor involved. Oxygen‐induced vasoconstriction may serve as a protective mechanism to reduce the oxidative burden to which a tissue is exposed, a process that is superimposed on top of the local mechanisms which regulate tissue blood flow to meet a tissue's metabolic demand. PMID:27324312

  1. Magnetic particles-based biosensor for biogenic amines using an optical oxygen sensor as a transducer

    Pospiskova, K.; Sebela, M.; Safarik, I.; Kuncova, G.

    2013-01-01

    We have developed a fibre optic biosensor with incorporated magnetic microparticles for the determination of biogenic amines. The enzyme diamine oxidase from Pisum sativum was immobilized either on chitosan-coated magnetic microparticles or on commercial microbeads modified with a ferrofluid. Both the immobilized enzyme and the ruthenium complex were incorporated into a UV-cured inorganic-organic polymer composite and deposited on a lens that was connected, by optical fibres, to an electro-optical detector. The enzyme catalyzes the oxidation of amines under consumption of oxygen. The latter was determined by measuring the quenched fluorescence lifetime of the ruthenium complex. The limits of detection for the biogenic amines putrescine and cadaverine are 25-30 μmol L -1 , and responses are linear up to a concentration of 1 mmol L -1 . (author)

  2. Accuracy of different sensors for the estimation of pollutant concentrations (total suspended solids, total and dissolved chemical oxygen demand) in wastewater and stormwater.

    Lepot, Mathieu; Aubin, Jean-Baptiste; Bertrand-Krajewski, Jean-Luc

    2013-01-01

    Many field investigations have used continuous sensors (turbidimeters and/or ultraviolet (UV)-visible spectrophotometers) to estimate with a short time step pollutant concentrations in sewer systems. Few, if any, publications compare the performance of various sensors for the same set of samples. Different surrogate sensors (turbidity sensors, UV-visible spectrophotometer, pH meter, conductivity meter and microwave sensor) were tested to link concentrations of total suspended solids (TSS), total and dissolved chemical oxygen demand (COD), and sensors' outputs. In the combined sewer at the inlet of a wastewater treatment plant, 94 samples were collected during dry weather, 44 samples were collected during wet weather, and 165 samples were collected under both dry and wet weather conditions. From these samples, triplicate standard laboratory analyses were performed and corresponding sensors outputs were recorded. Two outlier detection methods were developed, based, respectively, on the Mahalanobis and Euclidean distances. Several hundred regression models were tested, and the best ones (according to the root mean square error criterion) are presented in order of decreasing performance. No sensor appears as the best one for all three investigated pollutants.

  3. ZrO2 oxygen and hydrogen sensors: A geologic perspective

    Ulmer, G.C.

    1983-01-01

    The geosciences have been attracted to the high accuracy of 5 ZrO 2 cells for both f(O 2 ) and pH sensors. That the very same ZrO 2 membrane can be used above 600 0 C to sense f(O 2 ) and used between 25 0 and 300 0 C (maybe higher) to sense pH has been demonstrated. Specific resistivity measurements for such cells follow the equation log R = -2.20 + 4000/T (for T(K) from 298-1573 K) (for Y 2 O 3 levels of 4-8 mol%). In the lower-temperature regime, i.e., pH sensing, the ZrO 2 cell does not respond to changes in molecular O 2 or H 2 in its environment. Geochemical raw material impurities and ZrO 2 membrane fabrication techniques that affect f(O 2 ) and pH sensing are discussed. The application of ZrO 2 cells to various geologic redox equilibria are demonstrated by a few selected examples

  4. Wide-Field Imaging of Single-Nanoparticle Extinction with Sub-nm2 Sensitivity

    Payne, Lukas M.; Langbein, Wolfgang; Borri, Paola

    2018-03-01

    We report on a highly sensitive wide-field imaging technique for quantitative measurement of the optical extinction cross section σext of single nanoparticles. The technique is simple and high speed, and it enables the simultaneous acquisition of hundreds of nanoparticles for statistical analysis. Using rapid referencing, fast acquisition, and a deconvolution analysis, a shot-noise-limited sensitivity down to 0.4 nm2 is achieved. Measurements on a set of individual gold nanoparticles of 5 nm diameter using this method yield σext=(10.0 ±3.1 ) nm2, which is consistent with theoretical expectations and well above the background fluctuations of 0.9 nm2 .

  5. Single-Molecule Flow Platform for the Quantification of Biomolecules Attached to Single Nanoparticles.

    Jung, Seung-Ryoung; Han, Rui; Sun, Wei; Jiang, Yifei; Fujimoto, Bryant S; Yu, Jiangbo; Kuo, Chun-Ting; Rong, Yu; Zhou, Xing-Hua; Chiu, Daniel T

    2018-05-15

    We describe here a flow platform for quantifying the number of biomolecules on individual fluorescent nanoparticles. The platform combines line-confocal fluorescence detection with near nanoscale channels (1-2 μm in width and height) to achieve high single-molecule detection sensitivity and throughput. The number of biomolecules present on each nanoparticle was determined by deconvolving the fluorescence intensity distribution of single-nanoparticle-biomolecule complexes with the intensity distribution of single biomolecules. We demonstrate this approach by quantifying the number of streptavidins on individual semiconducting polymer dots (Pdots); streptavidin was rendered fluorescent using biotin-Alexa647. This flow platform has high-throughput (hundreds to thousands of nanoparticles detected per second) and requires minute amounts of sample (∼5 μL at a dilute concentration of 10 pM). This measurement method is an additional tool for characterizing synthetic or biological nanoparticles.

  6. Design and Characterization of a Sensorized Microfluidic Cell-Culture System with Electro-Thermal Micro-Pumps and Sensors for Cell Adhesion, Oxygen, and pH on a Glass Chip

    Sebastian M. Bonk

    2015-07-01

    Full Text Available We combined a multi-sensor glass-chip with a microfluidic channel grid for the characterization of cellular behavior. The grid was imprinted in poly-dimethyl-siloxane. Mouse-embryonal/fetal calvaria fibroblasts (MC3T3-E1 were used as a model system. Thin-film platinum (Pt sensors for respiration (amperometric oxygen electrode, acidification (potentiometric pH electrodes and cell adhesion (interdigitated-electrodes structures, IDES allowed us to monitor cell-physiological parameters as well as the cell-spreading behavior. Two on-chip electro-thermal micro-pumps (ETμPs permitted the induction of medium flow in the system, e.g., for medium mixing and drug delivery. The glass-wafer technology ensured the microscopic observability of the on-chip cell culture. Connecting Pt structures were passivated by a 1.2 μm layer of silicon nitride (Si3N4. Thin Si3N4 layers (20 nm or 60 nm were used as the sensitive material of the pH electrodes. These electrodes showed a linear behavior in the pH range from 4 to 9, with a sensitivity of up to 39 mV per pH step. The oxygen sensors were circular Pt electrodes with a sensor area of 78.5 μm2. Their sensitivity was 100 pA per 1% oxygen increase in the range from 0% to 21% oxygen (air saturated. Two different IDES geometries with 30- and 50-μm finger spacings showed comparable sensitivities in detecting the proliferation rate of MC3T3 cells. These cells were cultured for 11 days in vitro to test the biocompatibility, microfluidics and electric sensors of our system under standard laboratory conditions.

  7. Factors affecting the performance of a single-chamber microbial fuel cell-type biological oxygen demand sensor.

    Yang, Gai-Xiu; Sun, Yong-Ming; Kong, Xiao-Ying; Zhen, Feng; Li, Ying; Li, Lian-Hua; Lei, Ting-Zhou; Yuan, Zhen-Hong; Chen, Guan-Yi

    2013-01-01

    Microbial fuel cells (MFCs) are devices that exploit microorganisms as biocatalysts to degrade organic matter or sludge present in wastewater (WW), and thereby generate electricity. We developed a simple, low-cost single-chamber microbial fuel cell (SCMFC)-type biochemical oxygen demand (BOD) sensor using carbon felt (anode) and activated sludge, and demonstrated its feasibility in the construction of a real-time BOD measurement system. Further, the effects of anodic pH and organic concentration on SCMFC performance were examined, and the correlation between BOD concentration and its response time was analyzed. Our results demonstrated that the SCMFC exhibited a stable voltage after 132 min following the addition of synthetic WW (BOD concentration: 200 mg/L). Notably, the response signal increased with an increase in BOD concentration (range: 5-200 mg/L) and was found to be directly proportional to the substrate concentration. However, at higher BOD concentrations (>120 mg/L) the response signal remained unaltered. Furthermore, we optimized the SCMFC using synthetic WW, and tested it with real WW. Upon feeding real WW, the BOD values exhibited a standard deviation from 2.08 to 8.3% when compared to the standard BOD5 method, thus demonstrating the practical applicability of the developed system to real treatment effluents.

  8. Amperometric NOx-sensor for Combustion Exhaust Gas Control. Studies on transport properties and catalytic activity of oxygen permeable ceramic membranes

    Romer, E.W.J.

    2001-01-01

    The aim of the research described in this thesis is the development of a mixed conducting oxide layer, which can be used as an oxygen permselective membrane in an amperometric NOx sensor. The sensor will be used in exhaust gas systems. The exhaust gas-producing engine will run in the lean mix mode. The preparation of this sensor is carried out using screen-printing technology, in which the different layers of the sensor are applied successively. Hereafter, a co-firing step is applied in which all layers are sintered together. This co-firing step imposes several demands on the selection of materials. The design specifications of the sensor further include requirements concerning the operating temperature, measurement range and overall stability. The operating temperature of the sensor varies between 700 and 850C, enabling measurement of NOx concentrations between 50 and 1200 ppm with a measurement accuracy of 10 ppm. Concerning the stability of the sensor, it must withstand the exhaust gas atmosphere containing, amongst others, smoke, acids, abrasive particles and sulphur. Because of the chosen lean-mix engine concept, in which the fuel/air mixture switches continuously between lean (excess oxygen) and fat (excess fuel) mixtures, the sensor must withstand alternately oxidising and reducing atmospheres. Besides, it should be resistant to thermal shock and show no cross-sensitivity of NOx with other exhaust gas constituents like oxygen and hydrocarbons. The response time should be short, typically less than 500 ms. Because of the application in combustion engines of cars, the operational lifetime should be longer than 10 years. Demands on the mixed conducting oxide layer include the following ones. The layer should show minimal catalytic activity towards NOx-reduction. The oxygen permeability must be larger than 6.22 10 -8 mol/cm 2 s at a layer thickness between 3-50 μm. Since the mixed conducting oxide layer is coated on the YSZ electrolyte embodiment, the two

  9. Long-term performance of Aanderaa optodes and sea-bird SBE-43 dissolved-oxygen sensors bottom mounted at 32 m in Massachusetts Bay

    Martini, Marinna A.; Butman, Bradford; Mickelson, Michael J.

    2007-01-01

    A field evaluation of two new dissolved-oxygen sensing technologies, the Aanderaa Instruments AS optode model 3830 and the Sea-Bird Electronics, Inc., model SBE43, was carried out at about 32-m water depth in western Massachusetts Bay. The optode is an optical sensor that measures fluorescence quenching by oxygen molecules, while the SBE43 is a Clark polarographic membrane sensor. Optodes were continuously deployed on bottom tripod frames by exchanging sensors every 4 months over a 19-month period. A Sea-Bird SBE43 was added during one 4-month deployment. These moored observations compared well with oxygen measurements from profiles collected during monthly shipboard surveys conducted by the Massachusetts Water Resources Authority. The mean correlation coefficient between the moored measurements and shipboard survey data was >0.9, the mean difference was 0.06 mL L−1, and the standard deviation of the difference was 0.15 mL L−1. The correlation coefficient between the optode and the SBE43 was >0.9 and the mean difference was 0.07 mL L−1. Optode measurements degraded when fouling was severe enough to block oxygen molecules from entering the sensing foil over a significant portion of the sensing window. Drift observed in two optodes beginning at about 225 and 390 days of deployment is attributed to degradation of the sensing foil. Flushing is necessary to equilibrate the Sea-Bird sensor. Power consumption by the SBE43 and required pump was 19.2 mWh per sample, and the optode consumed 0.9 mWh per sample, both within expected values based on manufacturers’ specifications.

  10. Inkjet printing of nanoporous gold electrode arrays on cellulose membranes for high-sensitive paper-like electrochemical oxygen sensors using ionic liquid electrolytes.

    Hu, Chengguo; Bai, Xiaoyun; Wang, Yingkai; Jin, Wei; Zhang, Xuan; Hu, Shengshui

    2012-04-17

    A simple approach to the mass production of nanoporous gold electrode arrays on cellulose membranes for electrochemical sensing of oxygen using ionic liquid (IL) electrolytes was established. The approach, combining the inkjet printing of gold nanoparticle (GNP) patterns with the self-catalytic growth of these patterns into conducting layers, can fabricate hundreds of self-designed gold arrays on cellulose membranes within several hours using an inexpensive inkjet printer. The resulting paper-based gold electrode arrays (PGEAs) had several unique properties as thin-film sensor platforms, including good conductivity, excellent flexibility, high integration, and low cost. The porous nature of PGEAs also allowed the addition of electrolytes from the back cellulose membrane side and controllably produced large three-phase electrolyte/electrode/gas interfaces at the front electrode side. A novel paper-based solid-state electrochemical oxygen (O(2)) sensor was therefore developed using an IL electrolyte, 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF(6)). The sensor looked like a piece of paper but possessed high sensitivity for O(2) in a linear range from 0.054 to 0.177 v/v %, along with a low detection limit of 0.0075% and a short response time of less than 10 s, foreseeing its promising applications in developing cost-effective and environment-friendly paper-based electrochemical gas sensors.

  11. Minimizing the effects of oxygen interference on l-lactate sensors by a single amino acid mutation in Aerococcus viridansl-lactate oxidase.

    Hiraka, Kentaro; Kojima, Katsuhiro; Lin, Chi-En; Tsugawa, Wakako; Asano, Ryutaro; La Belle, Jeffrey T; Sode, Koji

    2018-04-30

    l-lactate biosensors employing l-lactate oxidase (LOx) have been developed mainly to measure l-lactate concentration for clinical diagnostics, sports medicine, and the food industry. Some l-lactate biosensors employ artificial electron mediators, but these can negatively impact the detection of l-lactate by competing with the primary electron acceptor: molecular oxygen. In this paper, a strategic approach to engineering an AvLOx that minimizes the effects of oxygen interference on sensor strips was reported. First, we predicted an oxygen access pathway in Aerococcus viridans LOx (AvLOx) based on its crystal structure. This was subsequently blocked by a bulky amino acid substitution. The resulting Ala96Leu mutant showed a drastic reduction in oxidase activity using molecular oxygen as the electron acceptor and a small increase in dehydrogenase activity employing an artificial electron acceptor. Secondly, the Ala96Leu mutant was immobilized on a screen-printed carbon electrode using glutaraldehyde cross-linking method. Amperometric analysis was performed with potassium ferricyanide as an electron mediator under argon or atmospheric conditions. Under argon condition, the response current increased linearly from 0.05 to 0.5mM l-lactate for both wild-type and Ala96Leu. However, under atmospheric conditions, the response of wild-type AvLOx electrode was suppressed by 9-12% due to oxygen interference. The Ala96Leu mutant maintained 56-69% of the response current at the same l-lactate level and minimized the relative bias error to -19% from -49% of wild-type. This study provided significant insight into the enzymatic reaction mechanism of AvLOx and presented a novel approach to minimize oxygen interference in sensor applications, which will enable accurate detection of l-lactate concentrations. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Highly sensitive immunoassay of protein molecules based on single nanoparticle fluorescence detection in a nanowell

    Han, Jin-Hee; Kim, Hee-Joo; Lakshmana, Sudheendra; Gee, Shirley J.; Hammock, Bruce D.; Kennedy, Ian M.

    2011-03-01

    A nanoarray based-single molecule detection system was developed for detecting proteins with extremely high sensitivity. The nanoarray was able to effectively trap nanoparticles conjugated with biological sample into nanowells by integrating with an electrophoretic particle entrapment system (EPES). The nanoarray/EPES is superior to other biosensor using immunoassays in terms of saving the amounts of biological solution and enhancing kinetics of antibody binding due to reduced steric hindrance from the neighboring biological molecules. The nanoarray patterned onto a layer of PMMA and LOL on conductive and transparent indium tin oxide (ITO)-glass slide by using e-beam lithography. The suspension of 500 nm-fluorescent (green emission)-carboxylated polystyrene (PS) particles coated with protein-A followed by BDE 47 polyclonal antibody was added to the chip that was connected to the positive voltage. The droplet was covered by another ITO-coated-glass slide and connected to a ground terminal. After trapping the particles into the nanowells, the solution of different concentrations of anti-rabbit- IgG labeled with Alexa 532 was added for an immunoassay. A single molecule detection system could quantify the anti-rabbit IgG down to atto-mole level by counting photons emitted from the fluorescent dye bound to a single nanoparticle in a nanowell.

  13. Sensor

    Gleeson, Helen; Dierking, Ingo; Grieve, Bruce; Woodyatt, Christopher; Brimicombe, Paul

    2015-01-01

    An electrical temperature sensor (10) comprises a liquid crystalline material (12). First and second electrically conductive contacts (14), (16), having a spaced relationship there between, contact the liquid crystalline material (12). An electric property measuring device is electrically connected to the first and second contacts (14), (16) and is arranged to measure an electric property of the liquid crystalline material (12). The liquid crystalline material (12) has a transition temperatur...

  14. Hot spot in GdBa2Cu3O7-δ-based composite ceramics rods and their applications for oxygen sensors

    Okamoto, T; Takata, M

    2011-01-01

    A hot spot, which is a local area glowing orange, appears in a LnBa 2 Cu 3 O 7-δ (Ln: rare earth element) ceramic rod when a voltage exceeding a certain value is applied to the rod at room temperature. After the appearance of the hot spot, the current changes according to the oxygen partial pressure in ambient atmosphere, which acts as an oxygen sensor without the need for any heating system. The GdBa 2 Cu 3 O 7-δ rod tended to be melted and broken by a sustained presence of the hot spot in a high oxygen partial pressure Po 2 (∼100 kPa). The composite rod containing high melting point materials, such as BaAl 2 O 4 , BaZrO 3 and Gd 2 BaCuO 5 , showed a remarkable high durability in O 2 atmosphere. In a low Po 2 ( 2 Cu3O 7-δ rod decreases to almost zero and the hot spot disappeared, resulting in an insensitive rod to oxygen. The composite rod containing CuO detected oxygen even in Po 2 < 0.002 kPa.

  15. Dissolved Oxygen Sensor in Animal-Borne Instruments: An Innovation for Monitoring the Health of Oceans and Investigating the Functioning of Marine Ecosystems.

    Bailleul, Frederic; Vacquie-Garcia, Jade; Guinet, Christophe

    2015-01-01

    The current decline in dissolved oxygen concentration within the oceans is a sensitive indicator of the effect of climate change on marine environment. However the impact of its declining on marine life and ecosystems' health is still quite unclear because of the difficulty in obtaining in situ data, especially in remote areas, like the Southern Ocean (SO). Southern elephant seals (Mirounga leonina) proved to be a relevant alternative to the traditional oceanographic platforms to measure physical and biogeochemical structure of oceanic regions rarely observed. In this study, we use a new stage of development in biologging technology to draw a picture of dissolved oxygen concentration in the SO. We present the first results obtained from a dissolved oxygen sensor added to Argos CTD-SRDL tags and deployed on 5 female elephant seals at Kerguelen. From October 2010 and October 2011, 742 oxygen profiles associated with temperature and salinity measurements were recorded. Whether a part of the data must be considered cautiously, especially because of offsets and temporal drifts of the sensors, the range of values recorded was consistent with a concomitant survey conducted from a research vessel (Keops-2 project). Once again, elephant seals reinforced the relationship between marine ecology and oceanography, delivering essential information about the water masses properties and the biological status of the Southern Ocean. But more than the presentation of a new stage of development in animal-borne instrumentation, this pilot study opens a new field of investigation in marine ecology and could be enlarged in a near future to other key marine predators, especially large fish species like swordfish, tuna or sharks, for which dissolved oxygen is expected to play a crucial role in distribution and behaviour.

  16. Dissolved Oxygen Sensor in Animal-Borne Instruments: An Innovation for Monitoring the Health of Oceans and Investigating the Functioning of Marine Ecosystems.

    Frederic Bailleul

    Full Text Available The current decline in dissolved oxygen concentration within the oceans is a sensitive indicator of the effect of climate change on marine environment. However the impact of its declining on marine life and ecosystems' health is still quite unclear because of the difficulty in obtaining in situ data, especially in remote areas, like the Southern Ocean (SO. Southern elephant seals (Mirounga leonina proved to be a relevant alternative to the traditional oceanographic platforms to measure physical and biogeochemical structure of oceanic regions rarely observed. In this study, we use a new stage of development in biologging technology to draw a picture of dissolved oxygen concentration in the SO. We present the first results obtained from a dissolved oxygen sensor added to Argos CTD-SRDL tags and deployed on 5 female elephant seals at Kerguelen. From October 2010 and October 2011, 742 oxygen profiles associated with temperature and salinity measurements were recorded. Whether a part of the data must be considered cautiously, especially because of offsets and temporal drifts of the sensors, the range of values recorded was consistent with a concomitant survey conducted from a research vessel (Keops-2 project. Once again, elephant seals reinforced the relationship between marine ecology and oceanography, delivering essential information about the water masses properties and the biological status of the Southern Ocean. But more than the presentation of a new stage of development in animal-borne instrumentation, this pilot study opens a new field of investigation in marine ecology and could be enlarged in a near future to other key marine predators, especially large fish species like swordfish, tuna or sharks, for which dissolved oxygen is expected to play a crucial role in distribution and behaviour.

  17. Study and development of a fluorescence based sensor system for monitoring oxygen in wine production : the WOW project

    Trivellin, Nicola; Barbisan, Diego; Badocco, Denis; Pastore, Paolo; Meneghesso, Gaudenzio; Meneghini, Matteo; Zanoni, Enrico; Belgioioso, Giuseppe; Cenedese, Angelo

    2018-01-01

    The importance of oxygen in the winemaking process is widely known, as it affects the chemical aspects and therefore the organoleptic characteristics of the final product. Hence, it is evident the usefulness of a continuous and real-time measurements of the levels of oxygen in the various stages of

  18. Influence of zirconium doping in ceria lattice as an active electrode in amperometric electrochemical ammonia gas sensor using oxygen pumping current

    Sharan, R.; Dutta, Atanu; Roy, Mainak

    2016-01-01

    An amperometric electrochemical sensor using Ce-Zr system as ammonia gas detecting electrode is reported. Using lanthanum gallate based electrolyte La_0_._8Sr_0_._2Ga_0_._8Mg_0_._1Ni_0_._1O_3 (LSGMN) and lanthanum strontium cobaltite La_0_._5Sr_0_._5CoO_3 (LSC) as oxygen reduction electrode, the sensor was found to be highly sensitive to NH_3 gas down to few ppm level, when operated in the temperature range 300-450°C. Keeping LSC electrodecomposition same, when sensing properties were studied with the variation of Zr concentration in ceria for active electrode, sensor with 30 mol % Zr doped ceria showed highest sensitivity of 28μA/ decade at 400°C. For all active electrodecompositions Ce_1_-_xZr_xO_2 (x = 0 to 0.7) highest sensitivity was observed at 400°C. All the sensors performed reproducibly with time response and recovery time 40 and 120 seconds respectively. (author)

  19. DELETION OR INHIBITION OF THE OXYGEN SENSOR PHD1 PROTECTS AGAINST ISCHEMIC STROKE VIA REPROGRAMMING OF NEURONAL METABOLISM

    Quaegebeur, Annelies; Segura, Inmaculada; Schmieder, Roberta; Verdegem, Dries; Decimo, Ilaria; Bifari, Francesco; Dresselaers, Tom; Eelen, Guy; Ghosh, Debapriva; Schoors, Sandra; Janaki Raman, Sudha Rani; Cruys, Bert; Govaerts, Kristof; De Legher, Carla; Bouché, Ann; Schoonjans, Luc; Ramer, Matt S.; Hung, Gene; Bossaert, Goele; Cleveland, Don W.; Himmelreich, Uwe; Voets, Thomas; Lemmens, Robin; Bennett, C. Frank; Robberecht, Wim; De Bock, Katrien; Dewerchin, Mieke; Fendt, Sarah-Maria; Ghesquière, Bart; Carmeliet, Peter

    2016-01-01

    Summary The oxygen-sensing prolyl hydroxylase domain proteins (PHDs) regulate cellular metabolism, but their role in neuronal metabolism during stroke is unknown. Here we report that PHD1 deficiency provides neuroprotection in a murine model of permanent brain ischemia. This was not due to an increased collateral vessel network, nor to enhanced neurotrophin expression. Instead, PHD1−/− neurons were protected against oxygen-nutrient deprivation by reprogramming glucose metabolism. Indeed, PHD1−/− neurons enhanced glucose flux through the oxidative pentose phosphate pathway by diverting glucose from glycolysis. As a result, PHD1−/− neurons increased their redox buffering capacity to scavenge oxygen radicals in ischemia. Intracerebroventricular injection of PHD1-antisense oligonucleotides reduced the cerebral infarct size and neurological deficits following stroke. These data identify PHD1 as a novel regulator of neuronal metabolism and a potential therapeutic target in ischemic stroke. PMID:26774962

  20. Deletion or Inhibition of the Oxygen Sensor PHD1 Protects against Ischemic Stroke via Reprogramming of Neuronal Metabolism.

    Quaegebeur, Annelies; Segura, Inmaculada; Schmieder, Roberta; Verdegem, Dries; Decimo, Ilaria; Bifari, Francesco; Dresselaers, Tom; Eelen, Guy; Ghosh, Debapriva; Davidson, Shawn M; Schoors, Sandra; Broekaert, Dorien; Cruys, Bert; Govaerts, Kristof; De Legher, Carla; Bouché, Ann; Schoonjans, Luc; Ramer, Matt S; Hung, Gene; Bossaert, Goele; Cleveland, Don W; Himmelreich, Uwe; Voets, Thomas; Lemmens, Robin; Bennett, C Frank; Robberecht, Wim; De Bock, Katrien; Dewerchin, Mieke; Ghesquière, Bart; Fendt, Sarah-Maria; Carmeliet, Peter

    2016-02-09

    The oxygen-sensing prolyl hydroxylase domain proteins (PHDs) regulate cellular metabolism, but their role in neuronal metabolism during stroke is unknown. Here we report that PHD1 deficiency provides neuroprotection in a murine model of permanent brain ischemia. This was not due to an increased collateral vessel network. Instead, PHD1(-/-) neurons were protected against oxygen-nutrient deprivation by reprogramming glucose metabolism. Indeed, PHD1(-/-) neurons enhanced glucose flux through the oxidative pentose phosphate pathway by diverting glucose away from glycolysis. As a result, PHD1(-/-) neurons increased their redox buffering capacity to scavenge oxygen radicals in ischemia. Intracerebroventricular injection of PHD1-antisense oligonucleotides reduced the cerebral infarct size and neurological deficits following stroke. These data identify PHD1 as a regulator of neuronal metabolism and a potential therapeutic target in ischemic stroke. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Hypoxia-dependent sequestration of an oxygen sensor by a widespread structural motif can shape the hypoxic response - a predictive kinetic model

    Novák Béla

    2010-10-01

    Full Text Available Abstract Background The activity of the heterodimeric transcription factor hypoxia inducible factor (HIF is regulated by the post-translational, oxygen-dependent hydroxylation of its α-subunit by members of the prolyl hydroxylase domain (PHD or EGLN-family and by factor inhibiting HIF (FIH. PHD-dependent hydroxylation targets HIFα for rapid proteasomal degradation; FIH-catalysed asparaginyl-hydroxylation of the C-terminal transactivation domain (CAD of HIFα suppresses the CAD-dependent subset of the extensive transcriptional responses induced by HIF. FIH can also hydroxylate ankyrin-repeat domain (ARD proteins, a large group of proteins which are functionally unrelated but share common structural features. Competition by ARD proteins for FIH is hypothesised to affect FIH activity towards HIFα; however the extent of this competition and its effect on the HIF-dependent hypoxic response are unknown. Results To analyse if and in which way the FIH/ARD protein interaction affects HIF-activity, we created a rate equation model. Our model predicts that an oxygen-regulated sequestration of FIH by ARD proteins significantly shapes the input/output characteristics of the HIF system. The FIH/ARD protein interaction is predicted to create an oxygen threshold for HIFα CAD-hydroxylation and to significantly sharpen the signal/response curves, which not only focuses HIFα CAD-hydroxylation into a defined range of oxygen tensions, but also makes the response ultrasensitive to varying oxygen tensions. Our model further suggests that the hydroxylation status of the ARD protein pool can encode the strength and the duration of a hypoxic episode, which may allow cells to memorise these features for a certain time period after reoxygenation. Conclusions The FIH/ARD protein interaction has the potential to contribute to oxygen-range finding, can sensitise the response to changes in oxygen levels, and can provide a memory of the strength and the duration of a

  2. Luminescent Oxygen Gas Sensors Based on Nanometer-Thick Hybrid Films of Iridium Complexes and Clay Minerals

    Hisako Sato

    2014-01-01

    Full Text Available The use of Ir(III complexes in photo-responsive molecular devices for oxygen gas sensing is reviewed. Attention is focused on the immobilization of Ir(III complexes in organic or inorganic host materials such as polymers, silica and clays in order to enhance robustness and reliability. Our recent works on constructing nanometer-thick films comprised of cyclometalated cationic Ir(III complexes and clay minerals are described. The achievement of multi-emitting properties in response to oxygen pressure is demonstrated.

  3. Oxygen sensor nanoparticles for monitoring bacterial growth and characterization of dose–response functions in microfluidic screenings

    Cao, Jialan; Köhler, J. Michael; Nagl, Stefan; Kothe, Erika

    2015-01-01

    We are presenting a microfluidic droplet-based system for non-invasive, simultaneous optical monitoring of oxygen during bacterial cultivation in nL-sized droplets using ∼350 nm nanobeads made from polystyrene and doped with the NIR-emitting oxygen probe platinum (II) 5, 10, 15, 20-meso-tetraphenyltetrabenzoporphyrin (PtTPTBP). Data were readout by a two-channel micro flow-through fluorimeter and a two-channel micro flow-through photometer. The time-resolved miniaturized optical multi endpoint detection was applied to simultaneously sense dissolved oxygen, cellular autofluorescence, and cell density in nL-sized segments. Two bacterial strains were studied that are resistant to heavy metal ions, viz. Streptomyces acidiscabies E13 and Psychrobacillus psychrodurans UrPLO1. The study has two main features in that it demonstrates (a) the possibility to monitor the changes in oxygen partial pressure during metabolic activity of different bacterial cultures inside droplets, and (b) the efficiency of droplet-based microfluidic techniques along with multi-parameter optical sensing for highly resolved microtoxicological screenings in aquatic systems. (author)

  4. Biocatalyst Screening with a Twist: Application of Oxygen Sensors Integrated in Microchannels for Screening Whole Cell Biocatalyst Variants

    Fernandes, Ana C.; Halder, Julia M.; Nestl, Bettina M.

    2018-01-01

    Selective oxidative functionalization of molecules is a highly relevant and often demanding reaction in organic chemistry. The use of biocatalysts allows the stereo- and regioselective introduction of oxygen molecules in organic compounds at milder conditions and avoids the use of complex group-p...

  5. Differential signal pathway activation and 5-HT function: the role of gut enterochromaffin cells as oxygen sensors.

    Haugen, Martin; Dammen, Rikard; Svejda, Bernhard; Gustafsson, Bjorn I; Pfragner, Roswitha; Modlin, Irvin; Kidd, Mark

    2012-11-15

    The chemomechanosensory function of the gut enterochromaffin (EC) cell enables it to respond to dietary agents and mechanical stretch. We hypothesized that the EC cell, which also sensed alterations in luminal or mucosal oxygen level, was physiologically sensitive to fluctuations in O(2). Given that low oxygen levels induce 5-HT production and secretion through a hypoxia inducible factor 1α (HIF-1α)-dependent pathway, we also hypothesized that increasing O(2) would reduce 5-HT production and secretion. Isolated normal EC cells as well as the well-characterized EC cell model KRJ-I were used to examine HIF signaling (luciferase-assays), hypoxia transcriptional response element (HRE)-mediated transcription (PCR), signaling pathways (Western blot), and 5-HT release (ELISA) during exposure to different oxygen levels. Normal EC cells and KRJ-I cells express HIF-1α, and transient transfection with Renilla luciferase under HRE control identified a hypoxia-mediated pathway in these cells. PCR confirmed activation of HIF-downstream targets, GLUT1, IGF2, and VEGF under reduced O(2) levels (0.5%). Reducing O(2) also elevated 5-HT secretion (2-3.2-fold) as well as protein levels of HIF-1α (1.7-3-fold). Increasing O(2) to 100% inhibited HRE-mediated signaling, transcription, reduced 5-HT secretion, and significantly lowered HIF-1α levels (∼75% of control). NF-κB signaling was also elevated during hypoxia (1.2-1.6-fold), but no significant changes were noted in PKA/cAMP. We concluded that gut EC cells are oxygen responsive, and alterations in O(2) levels differentially activate HIF-1α and tryptophan hydroxylase 1, as well as NF-κB signaling. This results in alterations in 5-HT production and secretion and identifies that the chemomechanosensory role of EC cells extends to oxygen sensing.

  6. Investigation of photoplethysmographic signals and blood oxygen saturation values on healthy volunteers during cuff-induced hypoperfusion using a multimode PPG/SpO₂ sensor.

    Shafique, M; Kyriacou, P A; Pal, S K

    2012-06-01

    Photoplethysmography (PPG) is a technique widely used to monitor volumetric blood changes induced by cardiac pulsations. Pulse oximetry uses the technique of PPG to estimate arterial oxygen saturation values (SpO₂). In poorly perfused tissues, SpO₂ readings may be compromised due to the poor quality of the PPG signals. A multimode finger PPG probe that operates simultaneously in reflectance, transmittance and a combined mode called "transreflectance" was developed, in an effort to improve the quality of the PPG signals in states of hypoperfusion. Experiments on 20 volunteers were conducted to evaluate the performance of the multimode PPG sensor and compare the results with a commercial transmittance pulse oximeter. A brachial blood pressure cuff was used to induce artificial hypoperfusion. Results showed that the amplitude of the transreflectance AC PPG signals were significantly different (p signals obtained from the other two conventional PPG sensors (reflectance and transmittance). At induced brachial pressures between 90 and 135 mmHg, the reflectance finger pulse oximeter failed 25 times (failure rate 42.2 %) to estimate SpO₂ values, whereas the transmittance pulse oximeter failed 8 times (failure rate 15.5 %). The transreflectance pulse oximeter failed only 3 times (failure rate 6.8 %) and the commercial pulse oximeter failed 17 times (failure rate 29.4 %).

  7. Structural characterization of the heme-based oxygen sensor, AfGcHK, its interactions with the cognate response regulator, and their combined mechanism of action in a bacterial two-component signaling system

    Stráňava, M.; Martínek, V.; Man, Petr; Fojtíková, V.; Kavan, Daniel; Vaněk, O.; Shimizu, T.; Martínková, M.

    2016-01-01

    Roč. 84, č. 10 (2016), s. 1375-1389 ISSN 1097-0134 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61388971 Keywords : heme-based oxygen sensor * histidine kinase * two-component signal transduction system Subject RIV: CE - Biochemistry

  8. Sensor employing internal reference electrode

    2013-01-01

    The present invention concerns a novel internal reference electrode as well as a novel sensing electrode for an improved internal reference oxygen sensor and the sensor employing same.......The present invention concerns a novel internal reference electrode as well as a novel sensing electrode for an improved internal reference oxygen sensor and the sensor employing same....

  9. Oxygen sensors and energy sensors act synergistically to achieve a graded alteration in gene expression: consequences for assessing the level of neuroprotection in response to stressors.

    Renshaw, Gillian M C; Warburton, Joshua; Girjes, Adeeb

    2004-01-01

    Changes in gene expression are associated with switching to an autoprotected phenotype in response to environmental and physiological stress. Ubiquitous molecular chaperones from the heat shock protein (HSP) superfamily confer neuronal protection that can be blocked by antibodies. Recent research has focused on the interactions between the molecular sensors that affect the increased expression of neuroprotective HSPs above constitutive levels. An examination of the conditions under which the expression of heat shock protein 70 (Hsp70) was up regulated in a hypoxia and anoxia tolerant tropical species, the epaulette shark (Hemiscyllium ocellatum), revealed that up-regulation was dependent on exceeding a stimulus threshold for an oxidative stressor. While hypoxic-preconditioning confers neuroprotective changes, there was no increase in the level of Hsp70 indicating that its increased expression was not associated with achieving a neuroprotected state in response to hypoxia in the epaulette shark. Conversely, there was a significant increase in Hsp70 in response to anoxic-preconditioning, highlighting the presence of a stimulus threshold barrier and raising the possibility that, in this species, Hsp70 contributes to the neuroprotective response to extreme crises, such as oxidative stress. Interestingly, there was a synergistic effect of coincident stressors on Hsp70 expression, which was revealed when metabolic stress was superimposed upon oxidative stress. Brain energy charge was significantly lower when adenosine receptor blockade, provided by treatment with aminophylline, was present prior to the final anoxic episode, under these circumstances, the level of Hsp70 induced was significantly higher than in the pair-matched saline treated controls. An understanding of the molecular and metabolic basis for neuroprotective switches, which result in an up-regulation of neuroprotective Hsp70 expression in the brain, is needed so that intervention strategies can be devised

  10. Kinetic Investigations of the Role of Factor Inhibiting Hypoxia-inducible Factor (FIH) as an Oxygen Sensor.

    Tarhonskaya, Hanna; Hardy, Adam P; Howe, Emily A; Loik, Nikita D; Kramer, Holger B; McCullagh, James S O; Schofield, Christopher J; Flashman, Emily

    2015-08-07

    The hypoxia-inducible factor (HIF) hydroxylases regulate hypoxia sensing in animals. In humans, they comprise three prolyl hydroxylases (PHD1-3 or EGLN1-3) and factor inhibiting HIF (FIH). FIH is an asparaginyl hydroxylase catalyzing post-translational modification of HIF-α, resulting in reduction of HIF-mediated transcription. Like the PHDs, FIH is proposed to have a hypoxia-sensing role in cells, enabling responses to changes in cellular O2 availability. PHD2, the most important human PHD isoform, is proposed to be biochemically/kinetically suited as a hypoxia sensor due to its relatively high sensitivity to changes in O2 concentration and slow reaction with O2. To ascertain whether these parameters are conserved among the HIF hydroxylases, we compared the reactions of FIH and PHD2 with O2. Consistent with previous reports, we found lower Km(app)(O2) values for FIH than for PHD2 with all HIF-derived substrates. Under pre-steady-state conditions, the O2-initiated FIH reaction is significantly faster than that of PHD2. We then investigated the kinetics with respect to O2 of the FIH reaction with ankyrin repeat domain (ARD) substrates. FIH has lower Km(app)(O2) values for the tested ARDs than HIF-α substrates, and pre-steady-state O2-initiated reactions were faster with ARDs than with HIF-α substrates. The results correlate with cellular studies showing that FIH is active at lower O2 concentrations than the PHDs and suggest that competition between HIF-α and ARDs for FIH is likely to be biologically relevant, particularly in hypoxic conditions. The overall results are consistent with the proposal that the kinetic properties of individual oxygenases reflect their biological capacity to act as hypoxia sensors. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Coordination and redox state-dependent structural changes of the heme-based oxygen sensor AfGcHK associated with intraprotein signal transduction.

    Stranava, Martin; Man, Petr; Skálová, Tereza; Kolenko, Petr; Blaha, Jan; Fojtikova, Veronika; Martínek, Václav; Dohnálek, Jan; Lengalova, Alzbeta; Rosůlek, Michal; Shimizu, Toru; Martínková, Markéta

    2017-12-22

    The heme-based oxygen sensor histidine kinase Af GcHK is part of a two-component signal transduction system in bacteria. O 2 binding to the Fe(II) heme complex of its N-terminal globin domain strongly stimulates autophosphorylation at His 183 in its C-terminal kinase domain. The 6-coordinate heme Fe(III)-OH - and -CN - complexes of Af GcHK are also active, but the 5-coordinate heme Fe(II) complex and the heme-free apo-form are inactive. Here, we determined the crystal structures of the isolated dimeric globin domains of the active Fe(III)-CN - and inactive 5-coordinate Fe(II) forms, revealing striking structural differences on the heme-proximal side of the globin domain. Using hydrogen/deuterium exchange coupled with mass spectrometry to characterize the conformations of the active and inactive forms of full-length Af GcHK in solution, we investigated the intramolecular signal transduction mechanisms. Major differences between the active and inactive forms were observed on the heme-proximal side (helix H5), at the dimerization interface (helices H6 and H7 and loop L7) of the globin domain and in the ATP-binding site (helices H9 and H11) of the kinase domain. Moreover, separation of the sensor and kinase domains, which deactivates catalysis, increased the solvent exposure of the globin domain-dimerization interface (helix H6) as well as the flexibility and solvent exposure of helix H11. Together, these results suggest that structural changes at the heme-proximal side, the globin domain-dimerization interface, and the ATP-binding site are important in the signal transduction mechanism of Af GcHK. We conclude that Af GcHK functions as an ensemble of molecules sampling at least two conformational states. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  12. Insights into signal transduction by a hybrid FixL: Denaturation study of on and off states of a multi-domain oxygen sensor.

    Guimarães, Wellinson G; Gondim, Ana C S; Costa, Pedro Mikael da Silva; Gilles-Gonzalez, Marie-Alda; Lopes, Luiz G F; Carepo, Marta S P; Sousa, Eduardo H S

    2017-07-01

    FixL from Rhizobium etli (ReFixL) is a hybrid oxygen sensor protein. Signal transduction in ReFixL is effected by a switch off of the kinase activity on binding of an oxygen molecule to ferrous heme iron in another domain. Cyanide can also inhibit the kinase activity upon binding to the heme iron in the ferric state. The unfolding by urea of the purified full-length ReFixL in both active pentacoordinate form, met-FixL(Fe III ) and inactive cyanomet-FixL (Fe III -CN - ) form was monitored by UV-visible absorption spectroscopy, circular dichroism (CD) and fluorescence spectroscopy. The CD and UV-visible absorption spectroscopy revealed two states during unfolding, whereas fluorescence spectroscopy identified a three-state unfolding mechanism. The unfolding mechanism was not altered for the active compared to the inactive state; however, differences in the ΔG H2O were observed. According to the CD results, compared to cyanomet-FixL, met-FixL was more stable towards chemical denaturation by urea (7.2 vs 4.8kJmol -1 ). By contrast, electronic spectroscopy monitoring of the Soret band showed cyanomet-FixL to be more stable than met-FixL (18.5 versus 36.2kJmol -1 ). For the three-state mechanism exhibited by fluorescence, the ΔG H2O for both denaturation steps were higher for the active-state met-FixL than for cyanomet-FixL. The overall stability of met-FixL is higher in comparison to cyanomet-FixL suggesting a more compact protein in the active form. Nonetheless, hydrogen bonding by bound cyanide in the inactive state promotes the stability of the heme domain. This work supports a model of signal transduction by FixL that is likely shared by other heme-based sensors. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. An applicable approach for extracting human heart rate and oxygen saturation during physical movements using a multi-wavelength illumination optoelectronic sensor system

    Alharbi, Samah; Hu, Sijung; Mulvaney, David; Blanos, Panagiotis

    2018-02-01

    The ability to gather physiological parameters such as heart rate (HR) and oxygen saturation (SpO2%) during physical movement allows to continuously monitor personal health status without disrupt their normal daily activities. Photoplethysmography (PPG) based pulse oximetry and similar principle devices are unable to extract the HR and SpO2% reliably during physical movement due to interference in the signals that arise from motion artefacts (MAs). In this research, a flexible reflectance multi-wavelength optoelectronic patch sensor (OEPS) has been developed to overcome the susceptibility of conventional pulse oximetry readings to MAs. The OEPS incorporates light embittered diodes as illumination sources with four different wavelengths, e.g. green, orange, red, and infrared unlike the conventional pulse oximetry devices that normally measure the skin absorption of only two wavelengths (red and infrared). The additional green and orange wavelengths were found to be distinguish to the absorption of deoxyhemoglobin (RHb) and oxyhemoglobin (HbO2). The reliability of extracting physiological parameters from the green and orange wavelengths is due to absorbed near to the surface of the skin, thereby shortening the optical path and so effectively reducing the influence of physical movements. To compensate of MAs, a three-axis accelerometer was used as a reference with help of adaptive filter to reduce MAs. The experiments were performed using 15 healthy subjects aged 20 to 30. The primary results show that there are no significant difference of heart rate and oxygen saturation measurements between commercial devices and OEPS Green (r=0.992), Orange(r=0.984), Red(r=0.952) and IR(r=0.97) and SpO2% (r = 0.982, p = 0.894).

  14. Iron-sulfur clusters as biological sensors: the chemistry of reactions with molecular oxygen and nitric oxide.

    Crack, Jason C; Green, Jeffrey; Thomson, Andrew J; Le Brun, Nick E

    2014-10-21

    Iron-sulfur cluster proteins exhibit a range of physicochemical properties that underpin their functional diversity in biology, which includes roles in electron transfer, catalysis, and gene regulation. Transcriptional regulators that utilize iron-sulfur clusters are a growing group that exploit the redox and coordination properties of the clusters to act as sensors of environmental conditions including O2, oxidative and nitrosative stress, and metabolic nutritional status. To understand the mechanism by which a cluster detects such analytes and then generates modulation of DNA-binding affinity, we have undertaken a combined strategy of in vivo and in vitro studies of a range of regulators. In vitro studies of iron-sulfur cluster proteins are particularly challenging because of the inherent reactivity and fragility of the cluster, often necessitating strict anaerobic conditions for all manipulations. Nevertheless, and as discussed in this Account, significant progress has been made over the past decade in studies of O2-sensing by the fumarate and nitrate reduction (FNR) regulator and, more recently, nitric oxide (NO)-sensing by WhiB-like (Wbl) and FNR proteins. Escherichia coli FNR binds a [4Fe-4S] cluster under anaerobic conditions leading to a DNA-binding dimeric form. Exposure to O2 converts the cluster to a [2Fe-2S] form, leading to protein monomerization and hence loss of DNA binding ability. Spectroscopic and kinetic studies have shown that the conversion proceeds via at least two steps and involves a [3Fe-4S](1+) intermediate. The second step involves the release of two bridging sulfide ions from the cluster that, unusually, are not released into solution but rather undergo oxidation to sulfane (S(0)) subsequently forming cysteine persulfides that then coordinate the [2Fe-2S] cluster. Studies of other [4Fe-4S] cluster proteins that undergo oxidative cluster conversion indicate that persulfide formation and coordination may be more common than previously

  15. Heterogeneously Nd3+ doped single nanoparticles for NIR-induced heat conversion, luminescence, and thermometry.

    Marciniak, Lukasz; Pilch, Aleksandra; Arabasz, Sebastian; Jin, Dayong; Bednarkiewicz, Artur

    2017-06-22

    The current frontier in nanomaterials engineering is to intentionally design and fabricate heterogeneous nanoparticles with desirable morphology and composition, and to integrate multiple functionalities through highly controlled epitaxial growth. Here we show that heterogeneous doping of Nd 3+ ions following a core-shell design already allows three optical functions, namely efficient (η > 72%) light-to-heat conversion, bright NIR emission, and sensitive (S R > 0.1% K -1 ) localized temperature quantification, to be built within a single ca. 25 nm nanoparticle. Importantly, all these optical functions operate within the transparent biological window of the NIR spectral region (λ exc ∼ 800 nm, λ emi ∼ 860 nm), in which light scattering and absorption by tissues and water are minimal. We find NaNdF 4 as a core is efficient in absorbing and converting 808 nm light to heat, while NaYF 4 :1%Nd 3+ as a shell is a temperature sensor based on the ratio-metric luminescence reading but an intermediate inert spacer shell, e.g. NaYF 4 , is necessary to insulate the heat convertor and thermometer by preventing the possible Nd-Nd energy relaxation. Moreover, we notice that while temperature sensitivity and luminescence intensity are optically stable, increased excitation intensity to generate heat above room temperature may saturate the sensing capacity of temperature feedback. We therefore propose a dual beam photoexcitation scheme as a solution for possible light-induced hyperthermia treatment.

  16. Assessment and Use of Optical Oxygen Sensors as Tools to Assist in Optimal Product Component Selection for the Development of Packs of Ready-to-Eat Mixed Salads and for the Non-Destructive Monitoring of in-Pack Oxygen Levels Using Chilled Storage.

    Hempel, Andreas W; O'Sullivan, Maurice G; Papkovsky, Dmitri B; Kerry, Joseph P

    2013-05-22

    Optical oxygen sensors were used to ascertain the level of oxygen consumed by individual salad leaves for optimised packaging of ready-to-eat (RTE) Italian salad mixes during refrigerated storage. Seven commonly found leaves in Italian salad mixes were individually assessed for oxygen utilisation in packs. Each leaf showed varying levels of respiration throughout storage. Using the information obtained, an experimental salad mix was formulated (termed Mix 3) which consisted of the four slowest respiring salad leaves-Escarole, Frisee, Red Batavia, Lollo Rosso. Mix 3 was then compared against two commercially available Italian salads; Mix 1 (Escarole, Frisee, Radicchio, Lollo Rosso) and Mix 2 (Cos, Frisee, Radicchio, Lollo Rosso). Optical sensors were used to non-destructively monitor oxygen usage in all mixes throughout storage. In addition to oxygen consumption, all three salad mixes were quality assessed in terms of microbial load and sensorial acceptability. In conclusion, Mix 3 was found to consume the least amount of oxygen over time, had the lowest microbial load and was most sensorially preferred ( p products.

  17. Introduction of water into the heme distal side by Leu65 mutations of an oxygen sensor, YddV, generates verdoheme and carbon monoxide, exerting the heme oxygenase reaction.

    Stranava, Martin; Martínková, Markéta; Stiborová, Marie; Man, Petr; Kitanishi, Kenichi; Muchová, Lucie; Vítek, Libor; Martínek, Václav; Shimizu, Toru

    2014-11-01

    The globin-coupled oxygen sensor, YddV, is a heme-based oxygen sensor diguanylate cyclase. Oxygen binding to the heme Fe(II) complex in the N-terminal sensor domain of this enzyme substantially enhances its diguanylate cyclase activity which is conducted in the C-terminal functional domain. Leu65 is located on the heme distal side and is important for keeping the stability of the heme Fe(II)-O2 complex by preventing the entry of the water molecule to the heme complex. In the present study, it was found that (i) Escherichia coli-overexpressed and purified L65N mutant of the isolated heme-bound domain of YddV (YddV-heme) contained the verdoheme iron complex and other modified heme complexes as determined by optical absorption spectroscopy and mass spectrometry; (ii) CO was generated in the reconstituted system composed of heme-bound L65N and NADPH:cytochrome P450 reductase as confirmed by gas chromatography; (iii) CO generation of heme-bound L65N in the reconstituted system was inhibited by superoxide dismutase and catalase. In a concordance with the result, the reactive oxygen species increased the CO generation; (iv) the E. coli cells overexpressing the L65N protein of YddV-heme also formed significant amounts of CO compared to the cells overexpressing the wild type protein; (v) generation of verdoheme and CO was also observed for other mutants at Leu65 as well, but to a lesser extent. Since Leu65 mutations are assumed to introduce the water molecule into the heme distal side of YddV-heme, it is suggested that the water molecule would significantly contribute to facilitating heme oxygenase reactions for the Leu65 mutants. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. pH dependence of cyanide binding to the ferric heme domain of the direct oxygen sensor from Escherichia coli and the effect of alkaline denaturation.

    Bidwai, Anil K; Ok, Esther Y; Erman, James E

    2008-09-30

    The spectrum of the ferric heme domain of the direct oxygen sensor protein from Escherichia coli ( EcDosH) has been measured between pH 3.0 and 12.6. EcDosH undergoes acid denaturation with an apparent p K a of 4.24 +/- 0.05 and a Hill coefficient of 3.1 +/- 0.6 and reversible alkaline denaturation with a p K a of 9.86 +/- 0.04 and a Hill coefficient of 1.1 +/- 0.1. Cyanide binding to EcDosH has been investigated between pH 4 and 11. The EcDosH-cyanide complex is most stable at pH 9 with a K D of 0.29 +/- 0.06 microM. The kinetics of cyanide binding are monophasic between pH 4 and 8. At pH >or=8.5, the reaction is biphasic with the fast phase dependent upon the cyanide concentration and the slow phase independent of cyanide. The slow phase is attributed to conversion of denatured EcDosH to the native state, with a pH-independent rate of 0.052 +/- 0.006 s (-1). The apparent association rate constant for cyanide binding to EcDosH increases from 3.6 +/- 0.1 M (-1) s (-1) at pH 4 to 520 +/- 20 M (-1) s (-1) at pH 11. The dissociation rate constant averages (8.6 +/- 1.3) x 10 (-5) s (-1) between pH 5 and 9, increasing to (1.4 +/- 0.1) x 10 (-3) s (-1) at pH 4 and (2.5 +/- 0.1) x 10 (-3) s (-1) at pH 12.2. The mechanism of cyanide binding is consistent with preferential binding of the cyanide anion to native EcDosH. The reactions of imidazole and H 2O 2 with ferric EcDosH were also investigated and show little reactivity.

  19. Size-dependent redox behavior of iron observed by in-situ single nanoparticle spectro-microscopy on well-defined model systems.

    Karim, Waiz; Kleibert, Armin; Hartfelder, Urs; Balan, Ana; Gobrecht, Jens; van Bokhoven, Jeroen A; Ekinci, Yasin

    2016-01-06

    Understanding the chemistry of nanoparticles is crucial in many applications. Their synthesis in a controlled manner and their characterization at the single particle level is essential to gain deeper insight into chemical mechanisms. In this work, single nanoparticle spectro-microscopy with top-down nanofabrication is demonstrated to study individual iron nanoparticles of nine different lateral dimensions from 80 nm down to 6 nm. The particles are probed simultaneously, under same conditions, during in-situ redox reaction using X-ray photoemission electron microscopy elucidating the size effect during the early stage of oxidation, yielding time-dependent evolution of iron oxides and the mechanism for the inter-conversion of oxides in nanoparticles. Fabrication of well-defined system followed by visualization and investigation of singled-out particles eliminates the ambiguities emerging from dispersed nanoparticles and reveals a significant increase in the initial rate of oxidation with decreasing size, but the reactivity per active site basis and the intrinsic chemical properties in the particles remain the same in the scale of interest. This advance of nanopatterning together with spatially-resolved single nanoparticle X-ray absorption spectroscopy will guide future discourse in understanding the impact of confinement of metal nanoparticles and pave way to solve fundamental questions in material science, chemical physics, magnetism, nanomedicine and nanocatalysis.

  20. Size-dependent redox behavior of iron observed by in-situ single nanoparticle spectro-microscopy on well-defined model systems

    Karim, Waiz; Kleibert, Armin; Hartfelder, Urs; Balan, Ana; Gobrecht, Jens; van Bokhoven, Jeroen A.; Ekinci, Yasin

    2016-01-01

    Understanding the chemistry of nanoparticles is crucial in many applications. Their synthesis in a controlled manner and their characterization at the single particle level is essential to gain deeper insight into chemical mechanisms. In this work, single nanoparticle spectro-microscopy with top-down nanofabrication is demonstrated to study individual iron nanoparticles of nine different lateral dimensions from 80 nm down to 6 nm. The particles are probed simultaneously, under same conditions, during in-situ redox reaction using X-ray photoemission electron microscopy elucidating the size effect during the early stage of oxidation, yielding time-dependent evolution of iron oxides and the mechanism for the inter-conversion of oxides in nanoparticles. Fabrication of well-defined system followed by visualization and investigation of singled-out particles eliminates the ambiguities emerging from dispersed nanoparticles and reveals a significant increase in the initial rate of oxidation with decreasing size, but the reactivity per active site basis and the intrinsic chemical properties in the particles remain the same in the scale of interest. This advance of nanopatterning together with spatially-resolved single nanoparticle X-ray absorption spectroscopy will guide future discourse in understanding the impact of confinement of metal nanoparticles and pave way to solve fundamental questions in material science, chemical physics, magnetism, nanomedicine and nanocatalysis.

  1. Silica Aerogels Doped with Ru(II) Tris 1,l0-Phenanthro1ine)-Electron Acceptor Dyads: Improving the Dynamic Range, Sensitivity and Response Time of Sol-Gel Based Oxygen Sensors

    Kevebtusm Bucgikas; Rawashdeh, Abdel M.; Elder, Ian A.; Yang, Jinhua; Dass, Amala; Sotiriou-Leventis, Chariklia

    2005-01-01

    Complexes 1 and 2 were characterized in fluid and frozen solution and as dopants of silica aerogels. The intramolecular quenching efficiency of pendant 4-benzoyl-N-methylpyridinium group (4BzPy) is solvent dependent: emission is quenched completely in acetonitrile but not in alcohols. On the other hand, N-benzyl-N'-methylviologen (BzMeV) quenches the emission in all solvents completely. The differences are traced electrochemically to a stronger solvation effect by the alcohol in the case of 1. In fiozen matrices or absorbed on the surfaces of silica aerogel, both 1 and 2 are photoluminescent. The lack of quenching has been traced to the environmental rigidity. When doped aerogels are cooled to 77K, the emission shifts to the blue and its intensity increases in analogy to what is observed with Ru(II) complexes in media undergoing fluid-to-rigid transition. The photoluminescence of 1 and 2 from the aerogel is quenched by oxygen diffusing through the pores. In the presence of oxygen, aerogels doped with 1 can modulate their emission over a wider dynamic range than aerogels doped with 2, and both are more sensitive than aerogels doped with Ru(II) tris(1,l0- phenanthroline). In contrast to frozen solutions, the luminescent moieties in the bulk of aerogels kept at 77K are still accessible, leading to more sensitive platforms for oxygen sensors than other ambient temperature configurations.

  2. Development of antifouling of electrochemical solid-state dissolved oxygen sensors based on nanostructured Cu0.4Ru3.4O7 + RuO2 sensing electrodes

    Zhuiykov, Serge; Kalantar-zadeh, Kourosh

    2012-01-01

    Tailoring nanostructured sensing electrode materials to high antifouling resistance has been one of the main priorities of the development of water quality sensors in the 21st century. Nanostructured Cu 0.4 Ru 3.4 O 7 + RuO 2 -SEs have been developed to address the bio-fouling problem. The change in Cu 0.4 Ru 3.4 O 7 + RuO 2 structural development being promoted by advances in nano- and micro-scale pattering. Nanostructured Cu 0.4 Ru 3.4 O 7 + RuO 2 -SEs with different mol% of Cu 2 O were screen-printed on alumina sensor substrates and were consequently subjected to a 3-month field trial at the Water Treatment Plant. Their structural and electrochemical properties before and after the experiment were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical cyclic voltammerty (CV) techniques. The relationship between dissolved oxygen (DO) and the sensor's potential difference was found to be relatively linear, with the maximum sensitivity of −46 mV per decade being achieved at 20 mol% Cu 2 O at 7.27 pH. Moreover, a 3-month field trial in the sewerage environment has shown that Cu 0.4 Ru 3.4 O 7 + RuO 2 -SE with 20 mol% of Cu 2 O possesses much higher defences against bio-fouling than the same SE with only 10 mol% of Cu 2 O. The super-hydrophobic property of the developed Cu 0.4 Ru 3.4 O 7 + RuO 2 complex oxide has been considered as one of the essential pre-requisites for high antifouling resistance. Multiple antifouling defence strategies from biomimetic to bio-inspired must be incorporated in further development of nanostructured oxide SE to solve problems of bio-fouling on the sensor's SE.

  3. Amperometric glucose sensor based on enhanced catalytic reduction of oxygen using glucose oxidase adsorbed onto core-shell Fe3O4-silica-Au magnetic nanoparticles

    Wang Aijun; Li Yongfang; Li Zhonghua; Feng Jiuju; Sun Yanli; Chen Jianrong

    2012-01-01

    Monodisperse Fe 3 O 4 magnetic nanoparticles (NPs) were prepared under facile solvothermal conditions and successively functionalized with silica and Au to form core/shell Fe 3 O 4 -silica-Au NPs. Furthermore, the samples were used as matrix to construct a glucose sensor based on glucose oxidase (GOD). The immobilized GOD retained its bioactivity with high protein load of 3.92 × 10 −9 mol·cm −2 , and exhibited a surface-controlled quasi-reversible redox reaction, with a fast heterogeneous electron transfer rate of 7.98 ± 0.6 s −1 . The glucose biosensor showed a broad linear range up to 3.97 mM with high sensitivity of 62.45 μA·mM −1 cm −2 and fast response (less than 5 s). - Graphical abstract: Core-shell structured Fe 3 O 4 -silica-Au nanoparticles were prepared and used as matrix to construct an amperometric glucose sensor based on glucose oxidase, which showed broad linear range, high sensitivity, and fast response. Highlights: ► Synthesis of monodispersed Fe 3 O 4 nanoparticles. ► Fabrication of core/shell Fe 3 O 4 -silica-Au nanoparticles. ► Construction of a novel glucose sensor with wide linear range, high sensitivity and fast response.

  4. Measurement of pO2 in a Pre-clinical Model of Rabbit Tumor Using OxyChip, a Paramagnetic Oxygen Sensor.

    Hou, H; Khan, N; Kuppusamy, P

    2017-01-01

    The objective of this work was to establish a novel and robust technology, based on electron paramagnetic resonance (EPR) oximetry, as a practical tool for measurement of tumor oxygen. Previously, we have reported on the development of oxygen-sensing paramagnetic crystals (LiNc-BuO) encapsulated in a biocompatible polymer, called OxyChip. In this report we present our recent data on the use of OxyChip for pO 2 measurements in the tumor of a pre-clinical, large-animal rabbit model. The results establish that OxyChip is capable of noninvasive and repeated measurement of pO 2 in a large animal model.

  5. Oxygen toxicity

    C. A. van der Westhuizen

    1990-07-01

    Full Text Available Oxygen has been discovered about 200 years ago. Since then the vital physiological involvement of oxygen in various biologi­cal processes, mainly energy production, has been established. However, in the body molecular oxygen can be converted to toxic oxygen metabolites such as superoxide anion, hydrogen peroxide, the hydroxyl radical and singlet oxygen. These toxic metabolites are produced mainly in the mitochondria, plasma membranes and endoplasmic reticulum.

  6. Determination of dissolved oxygen in saline waters applying mathematical methods and as a membrane electrode sensor; Determinacion de oxigeno disuelto en aguas salinas aplicando modelos matematicos y como sensor electrodo de membrana

    Mayari, R.; Espinosa, M. C.; Ruiz, M. [Centro Nacional de Investigaciones Ceintificas. La Habana (Cuba); Romero, E. [Universidad de Huelva (Spain)

    2000-07-01

    This work shows as specific methodology for the determination of dissolved oxygen in saline waters that allows to consider the variations of temperature and of concentration of salts. Both factors influence the solubility of the gases in water, making possible in place measurements, in bodies of water with content of salts unto of the concentration of sea water, with greater dependability. The mathematical models obtained are shown, the errors due to equipment, as well as the results obtained when applying this methodology in saline waters with diverse levels of contamination this allows to discern when the decrease of dissolved oxygen levels is due to an increase in the salinity or to an increase in the contamination of the water body. (Author) 7 refs.

  7. Effect of low-oxygen-concentration layer on iron gettering capability of carbon-cluster ion-implanted Si wafer for CMOS image sensors

    Onaka-Masada, Ayumi; Nakai, Toshiro; Okuyama, Ryosuke; Okuda, Hidehiko; Kadono, Takeshi; Hirose, Ryo; Koga, Yoshihiro; Kurita, Kazunari; Sueoka, Koji

    2018-02-01

    The effect of oxygen (O) concentration on the Fe gettering capability in a carbon-cluster (C3H5) ion-implanted region was investigated by comparing a Czochralski (CZ)-grown silicon substrate and an epitaxial growth layer. A high Fe gettering efficiency in a carbon-cluster ion-implanted epitaxial growth layer, which has a low oxygen region, was observed by deep-level transient spectroscopy (DLTS) and secondary ion mass spectroscopy (SIMS). It was demonstrated that the amount of gettered Fe in the epitaxial growth layer is approximately two times higher than that in the CZ-grown silicon substrate. Furthermore, by measuring the cathodeluminescence, the number of intrinsic point defects induced by carbon-cluster ion implantation was found to differ between the CZ-grown silicon substrate and the epitaxial growth layer. It is suggested that Fe gettering by carbon-cluster ion implantation comes through point defect clusters, and that O in the carbon-cluster ion-implanted region affects the formation of gettering sinks for Fe.

  8. Oxygen Therapy

    ... their breathing to dangerously low levels. Will I need oxygen when I sleep? Usually if you use supplemental oxygen during the ... your health care provider tells you you only need to use oxygen for exercise or sleep. Even if you feel “fine” off of your ...

  9. Organic Electroluminescent Sensor for Pressure Measurement

    Tomohide Niimi

    2012-10-01

    Full Text Available We have proposed a novel concept of a pressure sensor called electroluminescent pressure sensor (ELPS based on oxygen quenching of electroluminescence. The sensor was fabricated as an organic light-emitting device (OLED with phosphorescent dyes whose phosphorescence can be quenched by oxygenmolecules, and with a polymer electrode which permeates oxygen molecules. The sensor was a single-layer OLED with Platinum (II octaethylporphine (PtOEP doped into poly(vinylcarbazole (PVK as an oxygen sensitive emissive layer and poly(3,4-ethylenedioxythiophene mixed with poly(styrenesulfonate (PEDOT:PSS as an oxygen permeating polymer anode. The pressure sensitivity of the fabricated ELPS sample was equivalent to that of the sensor excited by an illumination light source. Moreover, the pressure sensitivity of the sensor is equivalent to that of conventional pressure-sensitive paint (PSP, which is an optical pressure sensor based on photoluminescence.

  10. Oxygen Therapy

    Bonnie Solmes

    2000-01-01

    Full Text Available LTOT is prescribed for people with chronic lung disease in whom there is a decrease in the ability of the lungs to supply enough oxygen to the body. The heart is obliged to pump faster to meet the body's oxygen requirements. This may place undue stress on the heart, resulting in palpitations, dizziness and fatigue. A low oxygen level in arterial blood is also harmful to the heart, the brain and the pulmonary blood vessels. Oxygen therapy is used to break this cycle. A person with low blood oxygen will often be able to accomplish more with less fatigue with the help of supplemental oxygen therapy. Shortness of breath is a mechanical problem resulting from the effects of chronic obstructive pulmonary disease. Oxygen therapy may or may not reduce shortness of breath, but it will help the lungs and heart to function with less stress.

  11. Sensor for ionizable elements

    Berkey, E.; Reed, W.A. III; Hickam, W.M.

    1977-01-01

    Sensor to detect thermally ionizable elements or molucules in air, water vapour or oxygen or to be used as alkali leak detector in vacuum systems, e.g. in the pipe system of a liquid-metal cooled FBR. The sensor consists of an filament made of thorium-containing iridium as cathode with a temperature upto 1000 0 C and an anode sheet of molybdenum, nickel or stainless steal. (ORU) [de

  12. Water quality sensor

    Ishizuka, Keiko; Takahashi, Masanori; Watanabe, Atsushi; Ibe, Hidefumi.

    1994-01-01

    The sensor of the present invention can directly measure oxygen/hydrogen peroxide concentrations in reactor water under radiation irradiation condition, and it has a long life time. Namely, an oxygen sensor comprises electrodes attached on both sides of high temperature/radiation resistant ion conductive material in which ions are sufficiently diffused within a temperature range of from a room temperature to 300degC. It has a performance for measuring electromotive force caused by the difference of a partial pressure between a reference gas and a gas to be measured contained in the high temperature/radiation resistant material. A hydrogen peroxide sensor has the oxygen sensor described above, to which a filter for causing decomposition of hydrogen peroxide is attached. The sensor of the present invention can directly measure oxygen/hydrogen peroxide concentrations in a reactor water of a BWR type reactor under high temperature/radiation irradiation condition. Accordingly, accurate water quality environment in the reactor water can be recognized. As a result, determination of incore corrosion environment is established thereby enabling to attain reactor integrity, safety and long life. (I.S.)

  13. A reduced-order adaptive neuro-fuzzy inference system model as a software sensor for rapid estimation of five-day biochemical oxygen demand

    Noori, Roohollah; Safavi, Salman; Nateghi Shahrokni, Seyyed Afshin

    2013-07-01

    The five-day biochemical oxygen demand (BOD5) is one of the key parameters in water quality management. In this study, a novel approach, i.e., reduced-order adaptive neuro-fuzzy inference system (ROANFIS) model was developed for rapid estimation of BOD5. In addition, an uncertainty analysis of adaptive neuro-fuzzy inference system (ANFIS) and ROANFIS models was carried out based on Monte-Carlo simulation. Accuracy analysis of ANFIS and ROANFIS models based on both developed discrepancy ratio and threshold statistics revealed that the selected ROANFIS model was superior. Pearson correlation coefficient (R) and root mean square error for the best fitted ROANFIS model were 0.96 and 7.12, respectively. Furthermore, uncertainty analysis of the developed models indicated that the selected ROANFIS had less uncertainty than the ANFIS model and accurately forecasted BOD5 in the Sefidrood River Basin. Besides, the uncertainty analysis also showed that bracketed predictions by 95% confidence bound and d-factor in the testing steps for the selected ROANFIS model were 94% and 0.83, respectively.

  14. One at a time: counting single-nanoparticle/electrode collisions for accurate particle sizing by overcoming the instability of gold nanoparticles under electrolytic conditions

    Qiu, Danfeng; Wang, Song; Zheng, Yuanqin; Deng, Zhaoxiang

    2013-01-01

    In response to an increasing demand for understanding electrochemical processes on the nanometer scale, it now becomes possible to monitor electron transfer reactions at the single-nanoparticle level, namely particle collision electrochemistry. This technique has great potential in the development of research tools towards single-particle electrocatalysis and selective and multiplexed particle sizing. However, one existing problem that may discourage these applications is the relatively weak colloidal stability of nanoparticles in an electrolytic solution. Here we report on a facile but efficient way to achieve a good stability of gold nanoparticles in an acidic media so that ‘zero-aggregation’ collisions can be achieved at a carbon ultramicroelectrode. This allows us to obtain anodic dissolution currents from individual nanoparticles in a ‘one particle at a time’ manner, based on which accurate particle sizing with a resolution of 1–2 nm can be achieved. Our work strongly suggests that to maintain a well dispersed nanoparticle solution during a particle impact electrochemical experiment is critically important for accurate particle sizing, as well as other applications that require information to be extracted from individual nanoparticles (not their aggregates). (paper)

  15. A flexible infrared sensor for tissue oximetry

    Petersen, Søren Dahl; Thyssen, Anders; Engholm, Mathias

    2013-01-01

    We present a flexible infrared sensor for use in tissue oximetry with the aim of treating prematurely born infants. The sensor will detect the oxygen saturation in brain tissue through near infrared spectroscopy. The sensor itself consists of several individual silicon photo detectors fully...

  16. Response behaviour of oxygen sensing solid electrolytes

    Winnubst, Aloysius J.A.; Scharenborg, A.H.A.; Burggraaf, A.J.

    1985-01-01

    The response time (t r) after a step change in oxygen partial pressure was investigated for some solid electrolytes used in Nernst type oxygen sensors. The electrolyte as well as the (porous) electrode material affect the value oft r. Stabilized Bi2O3 materials exhibit slower response rates (largert

  17. Measurement of oxygen transfer from air into organic solvents

    Ramesh, Hemalata; Mayr, Torsten; Hobisch, Mathias

    2016-01-01

    biological reactions require the supply of oxygen, most normally from air. However, reliable on-line measurements of oxygen concentration in organic solvents (and hence oxygen transfer rates from air to the solvent) has to date proven impossible due limitations in the current analytical methods. Results...... applications). Subsequently, we measured the oxygen transfer rates from air into these organic solvents. Conclusion The measurement of oxygen transfer rates from air into organic solvents using the dynamic method was established using the solvent resistant optical sensor. The feasibility of online oxygen...... For the first time, we demonstrate on-line oxygen measurements in non-aqueous media using a novel optical sensor. The sensor was used to measure oxygen concentration in various organic solvents including toluene, THF, isooctane, DMF, heptane and hexane (which have all been shown suitable for several biological...

  18. Taste sensor; Mikaku sensor

    Toko, K. [Kyushu University, Fukuoka (Japan)

    1998-03-05

    This paper introduces a taste sensor having a lipid/polymer membrane to work as a receptor of taste substances. The paper describes the following matters: this sensor uses a hollow polyvinyl chloride rod filled with KCl aqueous solution, and placed with silver and silver chloride wires, whose cross section is affixed with a lipid/polymer membrane as a lipid membrane electrode to identify taste from seven or eight kinds of response patterns of electric potential output from the lipid/polymer membrane; measurements of different substances presenting acidic taste, salty taste, bitter taste, sweet taste and flavor by using this sensor identified clearly each taste (similar response is shown to a similar taste even if the substances are different); different responses are indicated on different brands of beers; from the result of measuring a great variety of mineral waters, a possibility was suggested that this taste sensor could be used for water quality monitoring sensors; and application of this taste sensor may be expected as a maturation control sensor for Japanese sake (wine) and miso (bean paste) manufacturing. 2 figs., 1 tab.

  19. Oxygen safety

    ... sure you have working smoke detectors and a working fire extinguisher in your home. If you move around the house with your oxygen, you may need more than one fire extinguisher in different locations. Smoking can be very dangerous. No one should smoke ...

  20. Heme Sensor Proteins*

    Girvan, Hazel M.; Munro, Andrew W.

    2013-01-01

    Heme is a prosthetic group best known for roles in oxygen transport, oxidative catalysis, and respiratory electron transport. Recent years have seen the roles of heme extended to sensors of gases such as O2 and NO and cell redox state, and as mediators of cellular responses to changes in intracellular levels of these gases. The importance of heme is further evident from identification of proteins that bind heme reversibly, using it as a signal, e.g. to regulate gene expression in circadian rhythm pathways and control heme synthesis itself. In this minireview, we explore the current knowledge of the diverse roles of heme sensor proteins. PMID:23539616

  1. Oxygen therapy - infants

    ... breathe increased amounts of oxygen to get normal levels of oxygen in their blood. Oxygen therapy provides babies with the extra oxygen. Information Oxygen is a gas that the cells in your body need to work properly. The ...

  2. Ambient Sensors

    Börner, Dirk; Specht, Marcus

    2014-01-01

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

  3. Chemical sensors for nuclear industry

    Gnanasekaran, K.I.

    2012-01-01

    Development of chemical sensors for detection of gases at trace levels for applications in nuclear industry will be highlighted. The sensors have to be highly sensitive, reliable and rugged with long term stability to operate in harsh industrial environment. Semiconductor and solid electrolyte based electrochemical sensors satisfy the requirements. Physico-chemical aspects underlying the development of H 2 sensors in sodium and in cover gas circuit of the Fast breeder reactors for its smooth functioning, NH 3 and H 2 S sensors for use in Heavy water production industries and NO x sensors for spent fuel reprocessing plants will be presented. Development of oxygen sensors to monitor the oxygen level in the reactor containments and sodium sensors for detection of sodium leakages will also be discussed. The talk will focus the general aspects of identification of the sensing material for the respective analyte species, development of suitable chemical route for preparing them as fine powders, the need for configuring them in thick film or thin film geometries and their performance. Pulsed laser deposition method, an elegant technique to prepare the high quality thin films of multicomponent oxides is demonstrated for preparation of nanostructured thin films of complex oxides and its use in tailoring the morphology of the complex sensing material in the desired form by optimizing the in-situ growth conditions. (author)

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

    Hunter, Gary W.

    2005-01-01

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

  5. Air to fuel ratio sensor for internal combustion engine control system; Nainen kikan no nensho seigyoyo kunen hi sensor

    Tsuzuki, M.; Kawai, T.; Yamada, T.; Nishio [NGK Spark Plug Co. Ltd., Aichi (Japan)

    1998-06-01

    Air to fuel ratio sensor is used for emission control system of three-way catalyst, and constitutes the important functional part of combustion control system. For further precise combustion control application, universal air to fuel ratio heated exhaust gas oxygen sensor (UEGO sensor) has been developed. This paper introduces heater control system for constant element temperature of UEGO sensor. By the heater wattage feedback control of sensing cell impedance, the change of sensor element temperature is decreased. 9 refs., 13 figs.

  6. Attention Sensor

    Börner, Dirk; Kalz, Marco; Specht, Marcus

    2014-01-01

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

  7. Aquatic respiration rate measurements at low oxygen concentrations.

    Moritz Holtappels

    Full Text Available Despite its huge ecological importance, microbial oxygen respiration in pelagic waters is little studied, primarily due to methodological difficulties. Respiration measurements are challenging because of the required high resolution of oxygen concentration measurements. Recent improvements in oxygen sensing techniques bear great potential to overcome these limitations. Here we compare 3 different methods to measure oxygen consumption rates at low oxygen concentrations, utilizing amperometric Clark type sensors (STOX, optical sensors (optodes, and mass spectrometry in combination with (18-18O2 labeling. Oxygen concentrations and consumption rates agreed well between the different methods when applied in the same experimental setting. Oxygen consumption rates between 30 and 400 nmol L(-1 h(-1 were measured with high precision and relative standard errors of less than 3%. Rate detection limits in the range of 1 nmol L(-1 h(-1 were suitable for rate determinations in open ocean water and were lowest at the lowest applied O2 concentration.

  8. Evaluation of a new pulse oximeter sensor.

    Fernandez, Marco; Burns, Kathy; Calhoun, Beverly; George, Saramma; Martin, Beverly; Weaver, Chris

    2007-03-01

    A new forehead noninvasive oxygen saturation sensor may improve signal quality in patients with low cardiac index. To examine agreement between oxygen saturation values obtained by using digit-based and forehead pulse oximeters with arterial oxygen saturation in patients with low cardiac index. A method-comparison study was used to examine the agreement between 2 different pulse oximeters and arterial oxygen saturation in patients with low cardiac index. Readings were obtained from a finger and a forehead sensor and by analysis of a blood sample. Bias, precision, and root mean square differences were calculated for the digit and forehead sensors. Differences in bias and precision between the 2 noninvasive devices were evaluated with a t test (level of significance P<.05). Nineteen patients with low cardiac index (calculated as cardiac output in liters per minute divided by body surface area in square meters; mean 1.98, SD 0.34) were studied for a total of 54 sampling periods. Mean (SD) oxygen saturations were 97% (2.4) for blood samples, 96% (3.2) for the finger sensor, and 97% (2.8) for the forehead sensor. By Bland Altman analysis, bias +/- precision was -1.16 +/- 1.62% for the digit sensor and -0.36 +/- 1.74% for the forehead sensor; root mean square differences were 1.93% and 1.70%, respectively. Bias and precision differed significantly between the 2 devices; the forehead sensor differed less from the blood sample. In patients with low cardiac index, the forehead sensor was better than the digit sensor for pulse oximetry.

  9. Sensors, Volume 4, Thermal Sensors

    Scholz, Jorg; Ricolfi, Teresio

    1996-12-01

    'Sensors' is the first self-contained series to deal with the whole area of sensors. It describes general aspects, technical and physical fundamentals, construction, function, applications and developments of the various types of sensors. This volume describes the construction and applicational aspects of thermal sensors while presenting a rigorous treatment of the underlying physical principles. It provides a unique overview of the various categories of sensors as well as of specific groups, e.g. temperature sensors (resistance thermometers, thermocouples, and radiation thermometers), noise and acoustic thermometers, heat-flow and mass-flow sensors. Specific facettes of applications are presented by specialists from different fields including process control, automotive technology and cryogenics. This volume is an indispensable reference work and text book for both specialists and newcomers, researchers and developers.

  10. Gas Sensor

    Luebke, Ryan

    2015-01-22

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

  11. Gas Sensor

    Luebke, Ryan; Eddaoudi, Mohamed; Omran, Hesham; Belmabkhout, Youssef; Shekhah, Osama; Salama, Khaled N.

    2015-01-01

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

  12. Sensor web

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

    2011-01-01

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

  13. Oxygen and carbon dioxide sensing

    Ren, Fan (Inventor); Pearton, Stephen John (Inventor)

    2012-01-01

    A high electron mobility transistor (HEMT) capable of performing as a CO.sub.2 or O.sub.2 sensor is disclosed, hi one implementation, a polymer solar cell can be connected to the HEMT for use in an infrared detection system. In a second implementation, a selective recognition layer can be provided on a gate region of the HEMT. For carbon dioxide sensing, the selective recognition layer can be, in one example, PEI/starch. For oxygen sensing, the selective recognition layer can be, in one example, indium zinc oxide (IZO). In one application, the HEMTs can be used for the detection of carbon dioxide and oxygen in exhaled breath or blood.

  14. Ratiometric glucose sensing based on fluorescent oxygen films and glucose oxidase

    Fengyu Su; Liqiang Zhang; Xiangxing Kong; Fred Lee; Yanqing Tian; Deirdre R. Meldrum

    2017-01-01

    A new two-layer sensor film was constructed for sensing glucose based on glucose oxidase and oxygen sensing material. The first layer of film containing the oxygen sensor and intra-reference material was polymerized, then the second layer of glucose oxidase and glutaraldehyde was formed on the oxygen sensor layer. The two-layer sensor film has a resolution up to 0.05 mM and a detection range from 0 to 5 mM to glucose. The effects of pH and temperature on the sensing performance were systemati...

  15. Chemical sensors

    Hubbard, C.W.; Gordon, R.L.

    1987-05-01

    The revolution in analytical chemistry promised by recent developments in the field of chemical sensors has potential for significant positive impact on both research and production activities conducted by and for the Department of Energy. Analyses which were, in the past, performed only with a roomful of expensive equipment can now be performed with miniature solid-state electronic devices or small optical probes. Progress in the development of chemical sensors has been rapid, and the field is currently growing at a great rate. In accordance, Pacific Northwest Laboratory initiated a survey of recent literature so that contributors to active programs in research on analytical methods could be made aware of principles and applications of this new technology. This report presents the results of that survey. The sensors discussed here are divided into three types: micro solid-state devices, optical sensors, and piezoelectric crystal devices. The report is divided into three corresponding sections. The first section, ''Micro Solid-State Devices,'' discusses the design, operation, and application of electronic sensors that are produced in much the same way as standard solid-state electronic devices. The second section, ''Optrodes,'' covers the design and operation of chemical sensors that use fiber optics to detect chemically induced changes in optical properties. The final section, ''Piezoelectric Crystal Detectors,'' discusses two types of chemical sensors that depend on the changes in the properties of an oscillating piezoelectric crystal to detect the presence of certain materials. Advantages and disadvantages of each type of sensor are summarized in each section

  16. Ratiometric glucose sensing based on fluorescent oxygen films and glucose oxidase

    Fengyu Su

    2017-06-01

    Full Text Available A new two-layer sensor film was constructed for sensing glucose based on glucose oxidase and oxygen sensing material. The first layer of film containing the oxygen sensor and intra-reference material was polymerized, then the second layer of glucose oxidase and glutaraldehyde was formed on the oxygen sensor layer. The two-layer sensor film has a resolution up to 0.05 mM and a detection range from 0 to 5 mM to glucose. The effects of pH and temperature on the sensing performance were systematically investigated. The selective detection of glucose among other monosaccharides, such as fructose, mannose and galactose indicated that the sensing film has excellent selectivity. The prepared sensor was successfully applied for glucose sample detection of glucose concentration in artificial tears. Keywords: Glucose sensor, Glucose oxidase, Fluorescence, Oxygen film, Diabetes

  17. LUMOS - A Sensitive and Reliable Optode System for Measuring Dissolved Oxygen in the Nanomolar Range

    Lehner, Philipp; Larndorfer, Christoph; Garcia-Robledo, Emilio

    2015-01-01

    Most commercially available optical oxygen sensors target the measuring range of 300 to 2 mu mol L-1. However these are not suitable for investigating the nanomolar range which is relevant for many important environmental situations. We therefore developed a miniaturized phase fluorimeter based...... for read out of less sensitive optical oxygen sensors based on the same or similar indicator dyes, for example for monitoring oxygen at physiological conditions. The presented sensor system exhibits lower noise, higher resolution and higher sensitivity than the electrochemical STOX sensor previously used...... measurement system called the LUMOS (Luminescence Measuring Oxygen Sensor). It consists of a readout device and specialized "sensing chemistry" that relies on commercially available components. The sensor material is based on palladium(II)-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorphenyl)-porphyrin embedded...

  18. Microfabricated Chemical Sensors for Safety and Emission Control Applications

    Hunter, G. W.; Neudeck, P. G.; Chen, L.-Y.; Knight, D.; Liu, C. C.; Wu, Q. H.

    1998-01-01

    Chemical sensor technology is being developed for leak detection, emission monitoring, and fire safety applications. The development of these sensors is based on progress in two types of technology: 1) Micromachining and microfabrication (MicroElectroMechanical Systems (MEMS)-based) technology to fabricate miniaturized sensors. 2) The development of high temperature semiconductors, especially silicon carbide. Using these technologies, sensors to measure hydrogen, hydrocarbons, nitrogen oxides, carbon monoxide, oxygen, and carbon dioxide are being developed. A description is given of each sensor type and its present stage of development. It is concluded that microfabricated sensor technology has significant potential for use in a range of aerospace applications.

  19. Dually Fluorescent Sensing of pH and Dissolved Oxygen Using a Membrane Made from Polymerizable Sensing Monomers

    Tian, Yanqing; Shumway, Bradley R.; Youngbull, A. Cody; Li, Yongzhong; Jen, Alex K.-Y.; Johnson, Roger H.; Meldrum, Deirdre R.

    2010-01-01

    Using a thermal polymerization approach and polymerizable pH and oxygen sensing monomers with green and red emission spectra, respectively, new pH, oxygen, and their dual sensing membranes were prepared using poly(2-hydroxyethyl methacrylate)-co-poly(acrylamide) as a matrix. The sensors were grafted on acrylate-modified quartz glass and characterized under different pH values, oxygen concentrations, ion strengths, temperatures and cell culture media. The pH and oxygen sensors were excited usi...

  20. Amperometric glucose sensor based on enhanced catalytic reduction of oxygen using glucose oxidase adsorbed onto core-shell Fe{sub 3}O{sub 4}-silica-Au magnetic nanoparticles

    Wang Aijun [College of Geography and Environmental Science, College of Chemistry and Life Science, Zhejiang Normal University, Jinhua 321004 (China); Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Environmental Science, Henan Normal University, Xinxiang 453007 (China); Li Yongfang [College of Chemistry and Chemical Engineering, Henan Institute of Science and Technology, Xinxiang 453003 (China); Li Zhonghua [Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Environmental Science, Henan Normal University, Xinxiang 453007 (China); Feng Jiuju, E-mail: jjfengnju@gmail.com [College of Geography and Environmental Science, College of Chemistry and Life Science, Zhejiang Normal University, Jinhua 321004 (China); Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Environmental Science, Henan Normal University, Xinxiang 453007 (China); Sun Yanli [Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Environmental Science, Henan Normal University, Xinxiang 453007 (China); Chen Jianrong [College of Geography and Environmental Science, College of Chemistry and Life Science, Zhejiang Normal University, Jinhua 321004 (China)

    2012-08-01

    Monodisperse Fe{sub 3}O{sub 4} magnetic nanoparticles (NPs) were prepared under facile solvothermal conditions and successively functionalized with silica and Au to form core/shell Fe{sub 3}O{sub 4}-silica-Au NPs. Furthermore, the samples were used as matrix to construct a glucose sensor based on glucose oxidase (GOD). The immobilized GOD retained its bioactivity with high protein load of 3.92 Multiplication-Sign 10{sup -9} mol{center_dot}cm{sup -2}, and exhibited a surface-controlled quasi-reversible redox reaction, with a fast heterogeneous electron transfer rate of 7.98 {+-} 0.6 s{sup -1}. The glucose biosensor showed a broad linear range up to 3.97 mM with high sensitivity of 62.45 {mu}A{center_dot}mM{sup -1} cm{sup -2} and fast response (less than 5 s). - Graphical abstract: Core-shell structured Fe{sub 3}O{sub 4}-silica-Au nanoparticles were prepared and used as matrix to construct an amperometric glucose sensor based on glucose oxidase, which showed broad linear range, high sensitivity, and fast response. Highlights: Black-Right-Pointing-Pointer Synthesis of monodispersed Fe{sub 3}O{sub 4} nanoparticles. Black-Right-Pointing-Pointer Fabrication of core/shell Fe{sub 3}O{sub 4}-silica-Au nanoparticles. Black-Right-Pointing-Pointer Construction of a novel glucose sensor with wide linear range, high sensitivity and fast response.

  1. Automotive sensors

    Marek, Jiri; Illing, Matthias

    2003-01-01

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

  2. Piezoceramic Sensors

    Sharapov, Valeriy

    2011-01-01

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

  3. Artificial oxygen transport protein

    Dutton, P. Leslie

    2014-09-30

    This invention provides heme-containing peptides capable of binding molecular oxygen at room temperature. These compounds may be useful in the absorption of molecular oxygen from molecular oxygen-containing atmospheres. Also included in the invention are methods for treating an oxygen transport deficiency in a mammal.

  4. Neural network-based sensor signal accelerator.

    Vogt, M. C.

    2000-10-16

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

  5. Optischer Sensor

    Brandenburg, A.; Hutter, F.; Edelhaeuser, R.

    1992-01-01

    WO 2010040565 A1 UPAB: 20100506 NOVELTY - The integrated optical sensor comprises a first waveguide (4), a second waveguide (5) optically coupled to the first waveguide via a directional coupler, a substrate, which carries the first and the second waveguides, a single waveguide coupled with a light source, and an output waveguide coupled with a light-sensitive element. The sensor has a functional surface in the region of the directional coupler for depositing or deposition of the substance to...

  6. Wireless sensor

    Lamberti, Vincent E.; Howell, JR, Layton N.; Mee, David K.; Sepaniak, Michael J.

    2016-02-09

    Disclosed is a sensor for detecting a target material. The sensor includes a ferromagnetic metal and a molecular recognition reagent coupled to the ferromagnetic metal. The molecular recognition reagent is operable to expand upon exposure to vapor or liquid from the target material such that the molecular recognition reagent changes a tensile stress upon the ferromagnetic metal. The target material is detected based on changes in the magnetic switching characteristics of the ferromagnetic metal caused by the changes in the tensile stress.

  7. Sensitivity of microstructure fibers to gaseous oxygen

    Matějec, Vlastimil; Mrázek, Jan; Hayer, Miloš; Podrazký, Ondřej; Kaňka, Jiří; Kašík, Ivan

    2008-01-01

    Roč. 28, 5/6 (2008), s. 876-881 ISSN 0928-4931. [Journees Maghreb-Europe sur les Materiaux et Leurs Applications aux Dispositifs et Capteurs MADICA 2006 /5./. Mahdia, 30.10.2006-01.11.2006] R&D Projects: GA ČR GA102/05/0956 Institutional research plan: CEZ:AV0Z20670512 Keywords : detection * fibre optic sensors * oxygen * sol-gel processing * aerogels Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 1.812, year: 2008

  8. Coolant Chemistry Control: Oxygen Mass Transport in Lead Bismuth Eutectic

    Weisenburger, A.; Mueller, G.; Bruzzese, C.; Glass, A.

    2015-01-01

    In lead-bismuth cooled transmutation systems, oxygen, dissolved in the coolant at defined quantities, is required for stable long-term operation by assuring the formation of protective oxide scales on structural steel surfaces. Extracted oxygen must be permanently delivered to the system and distributed in the entire core. Therefore, coolant chemistry control involves detailed knowledge on oxygen mass transport. Beside the different flow regimes a core might have stagnant areas at which oxygen delivery can only be realised by diffusion. The difference between oxygen transport in flow paths and in stagnant zones is one of the targets of such experiments. To investigate oxygen mass transport in flowing and stagnant conditions, a dedicated facility was designed based on computational fluid dynamics (CFD). CFD also was applied to define the position of oxygen sensors and ultrasonic Doppler velocimetry transducers for flow measurements. This contribution will present the test facility, design relevant CFD calculations and results of first tests performed. (authors)

  9. In situ measurements of oxygen dynamics in unsaturated archaeological deposits

    Matthiesen, Henning; Hollesen, Jørgen; Dunlop, Rory

    2015-01-01

    Oxygen is a key parameter in the degradation of archaeological material, but little is known of its dynamics in situ. In this study, 10 optical oxygen sensors placed in a 2 m deep test pit in the cultural deposits at Bryggen in Bergen have monitored oxygen concentrations every half hour for more ...... of the soil exceeds 10–15% vol, while oxygen dissolved in infiltrating rainwater is of less importance for the supply of oxygen in the unsaturated zone....... than a year. It is shown that there is a significant spatial and temporal variation in the oxygen concentration, which is correlated to measured soil characteristics, precipitation, soil water content and degradation of organic material. In these deposits oxygen typically occurs when the air content...

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

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

    2002-01-01

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

  11. Radiation sensor

    Brown, W.L.; Geronime, R.L.

    1977-01-01

    Radiation sensor and thermocouple, respectively, which can be used for reactor in-core instrumentation. The radiation sensor consists of an inconel conductor wire and rhodium emitter wire, the thermocouple of two intertwined alumel or chromel wires. Both are arranged in the center of a metal tube relative to which they are separated by an insulator made of SiO 2 fibers. This insulator is first introduced as a loose fabric between the radiation sensor and the thermocouple, respectively, and the metal tube and then compacted to a density of 35-73% of pure SiO 2 by drawing the tube. There is no need for soldering or welding. The insulation resistivity at room temperature ist between 10 14 and 10 15 ohms. (ORU) [de

  12. Water Sensors

    1992-01-01

    Mike Morris, former Associate Director of STAC, formed pHish Doctor, Inc. to develop and sell a pH monitor for home aquariums. The monitor, or pHish Doctor, consists of a sensor strip and color chart that continually measures pH levels in an aquarium. This is important because when the level gets too high, ammonia excreted by fish is highly toxic; at low pH, bacteria that normally break down waste products stop functioning. Sales have run into the tens of thousands of dollars. A NASA Tech Brief Technical Support Package later led to a salt water version of the system and a DoE Small Business Innovation Research (SBIR) grant for development of a sensor for sea buoys. The company, now known as Ocean Optics, Inc., is currently studying the effects of carbon dioxide buildup as well as exploring other commercial applications for the fiber optic sensor.

  13. Biogeochemistry: Oxygen burrowed away

    Meysman, F.J.R.

    2014-01-01

    Multicellular animals probably evolved at the seafloor after a rise in oceanic oxygen levels. Biogeochemical model simulations suggest that as these animals started to rework the seafloor, they triggered a negative feedback that reduced global oxygen.

  14. Oxygen transport membrane

    2015-01-01

    The present invention relates to a novel composite oxygen transport membrane as well as its preparation and uses thereof.......The present invention relates to a novel composite oxygen transport membrane as well as its preparation and uses thereof....

  15. Proterozoic atmospheric oxygen

    Canfield, Donald Eugene

    2014-01-01

    This article is concerned with the evolution of atmospheric oxygen concentrations through the Proterozoic Eon. In particular, this article will seek to place the history of atmospheric oxygenation through the Proterozoic Eon in the context of the evolving physical environment including the history...... of continental growth and volcanic outgassing, as well as biogeochemical processing of elements within the oceans. The author will seek to explore constraints on the history of oxygenation and understand which processes have regulated oxygen through this eon....

  16. Oxygen evolution reaction catalysis

    Haber, Joel A.; Jin, Jian; Xiang, Chengxiang; Gregoire, John M.; Jones, Ryan J.; Guevarra, Dan W.; Shinde, Aniketa A.

    2016-09-06

    An Oxygen Evolution Reaction (OER) catalyst includes a metal oxide that includes oxygen, cerium, and one or more second metals. In some instances, the cerium is 10 to 80 molar % of the metals in the metal oxide and/or the catalyst includes two or more second metals. The OER catalyst can be included in or on an electrode. The electrode can be arranged in an oxygen evolution system such that the Oxygen Evolution Reaction occurs at the electrode.

  17. Advancement of Miniature Optic Gas Sensor (MOGS) Probe Technology

    Chullen, Cinda

    2015-01-01

    Advancement of Miniature Optic Gas Sensor (MOGS) Probe Technology" project will investigate newly developed optic gas sensors delivered from a Small Business Innovative Research (SBIR) Phase II effort. A ventilation test rig will be designed and fabricated to test the sensors while integrated with a Suited Manikin Test Apparatus (SMTA). Once the sensors are integrated, a series of test points will be completed to verify that the sensors can withstand Advanced Suit Portable Life Support System (PLSS) environments and associated human metabolic profiles for changes in pressure and levels of Oxygen (ppO2), carbon dioxide (ppCO2), and humidity (ppH2O).

  18. [Domiciliary oxygen therapy].

    Abdel Kafi, S

    2010-09-01

    In Belgium, oxygen therapy is becoming more and more accessible. When oxygen is needed for short periods or for special indications as palliative care, an agreement between mutual insurance companies and pharmacists allows the practitioner the home installation of gazeous oxygen cylinder or of oxygen concentrator. When long term oxygen therapy (LTOT) is indicated for patients with respiratory insufficiency, the pneumologist must first ask the INAMI the authorization to install one of the following modalities: oxygen concentrator with or without demand oxygen delivery cylinder and liquid oxygen. The goal of LTOT is to increase survival and quality of life. The principal and well accepted indication for LTOT is severe hypoxemia. The beneficial effects of oxygen therapy limited at night or on exertion are controversial. In order to increase patient's autonomy, oxygen can be prescribed for ambulation, respecting prescription's rules. At each step of oxygen therapy implementing (indication, choice of the device and follow-up) the patient under oxygen may benefit from a joint approach between the general practitioner and the chest specialist.

  19. Aircraft Oxygen Generation

    2012-02-01

    An Oxygen Enriched Air System for the AV-8A Harrier (NADC-81198-60).” 70 Horch , T., et. al. “The F-16 Onboard Oxygen Generating System: Performance...Only and Safety Privileged). Horch , T., Miller, R., Bomar, J., Tedor, J., Holden, R., Ikels, K., & Lozano, P. (1983). The F-16 Onboard Oxygen

  20. Fiber optic medical and fluorescent sensors and applications; Proceedings of the Meeting, Los Angeles, CA, Jan. 23, 24, 1992

    Hansmann, D.R.; Milanovich, F.P.; Vurek, G.G.; Walt, D.R. (3M Center, Saint Paul, MN (United States) Lawrence Livermore National Laboratory, Livermore, CA (United States) Abbott Laboratories, North Chicago, IL (United States) Tufts University, Medford, MA (United States))

    1992-01-01

    Papers are presented on such topics as the optical measurement of blood gases; waveguide ellipsometry biosensors; a novel fiber-optic radiation sensor for in vivo dosimetry; and a fiber-optic sensor for simultaneous oxygen saturation and blood pressure measurements. Fluorescent sensors are then considered with reference to sensor fabrication and design, and fluorescence sensing schemes, indicators, and reagents.

  1. Practical Use Technique of Sensor

    Hwang, Gyu Seop

    1985-11-01

    This book tells of practical use technology of sensor, introducing the recent trend of sensor for electronic industry, IC temperature sensor, radiation temperature sensor of surface acoustic wave, optical fiber temperature sensor, a polyelectrolyte film humidity sensor, semiconductor pressure sensor for industrial instrumentation, silicon integration pressure sensor, thick film humidity sensor and its application, photo sensor reflection type, and color sensor. It also deals with sensor for FA, sensor for a robot and sensor for the chemical industry.

  2. Practical Use Technique of Sensor

    Hwang, Gyu Seop

    1985-11-15

    This book tells of practical use technology of sensor, introducing the recent trend of sensor for electronic industry, IC temperature sensor, radiation temperature sensor of surface acoustic wave, optical fiber temperature sensor, a polyelectrolyte film humidity sensor, semiconductor pressure sensor for industrial instrumentation, silicon integration pressure sensor, thick film humidity sensor and its application, photo sensor reflection type, and color sensor. It also deals with sensor for FA, sensor for a robot and sensor for the chemical industry.

  3. Chemical sensor

    Rauh, R. David (Inventor)

    1990-01-01

    A sensor for detecting a chemical substance includes an insertion element having a structure which enables insertion of the chemical substance with a resulting change in the bulk electrical characteristics of the insertion element under conditions sufficient to permit effective insertion; the change in the bulk electrical characteristics of the insertion element is detected as an indication of the presence of the chemical substance.

  4. Load sensor

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

    2007-01-01

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

  5. Gas sensor

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

    2014-09-09

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

  6. A high reliability oxygen deficiency monitoring system

    Parry, R.; Claborn, G.; Haas, A.; Landis, R.; Page, W.; Smith, J.

    1993-01-01

    The escalating use of cryogens at national laboratories in general and accelerators in particular, along with the increased emphasis placed on personnel safety, mandates the development and installation of oxygen monitoring systems to insure personnel safety in the event of a cryogenic leak. Numerous vendors offer oxygen deficiency monitoring systems but fail to provide important features and/or flexibility. This paper describes a unique oxygen monitoring system developed for the Magnet Test Laboratory (MTL) at the Superconducting Super Collider Laboratory (SSCL). Features include: high reliability, oxygen cell redundancy, sensor longevity, simple calibration, multiple trip points, offending sensor audio and visual indication, global alarms for building evacuation, local and remote analog readout, event and analog data logging, EMAIL event notification, phone line voice status system, and multi-drop communications network capability for reduced cable runs. Of particular importance is the distributed topology of the system which allows it to operate in a stand-alone configuration or to communicate with a host computer. This flexibility makes it ideal for small applications such as a small room containing a cryogenic dewar, as well as larger systems which monitor many offices and labs in several buildings

  7. A high reliability oxygen deficiency monitoring system

    Parry, R.; Claborn, G.; Haas, A.; Landis, R.; Page, W.; Smith, J.

    1993-05-01

    The escalating use of cryogens at national laboratories in general and accelerators in particular, along with the increased emphasis placed on personnel safety, mandates the development and installation of oxygen monitoring systems to insure personnel safety in the event of a cryogenic leak. Numerous vendors offer oxygen deficiency monitoring systems but fail to provide important features and/or flexibility. This paper describes a unique oxygen monitoring system developed for the Magnet Test Laboratory (MTL) at the Superconducting Super Collider Laboratory (SSCL). Features include: high reliability, oxygen cell redundancy, sensor longevity, simple calibration, multiple trip points, offending sensor audio and visual indication, global alarms for building evacuation, local and remote analog readout, event and analog data logging, EMAIL event notification, phone line voice status system, and multi-drop communications network capability for reduced cable runs. Of particular importance is the distributed topology of the system which allows it to operate in a stand-alone configuration or to communicate with a host computer. This flexibility makes it ideal for small applications such as a small room containing a cryogenic dewar, as well as larger systems which monitor many offices and labs in several buildings

  8. On electrochemical sensor for determining elemental iodine in gas media

    Goffman, V.G.; Shajmerdinov, B.U.; Kotelkin, I.M.; Mikhajlova, A.M.; Dobrovol'skij, Yu.A.

    1993-01-01

    The possibility to use solid electrolyte cells of Ag, AgI/AgI/Au as sensors for determining concentration of element iodine in gaseous media was studied. Independent character of sensor parameters on oxygen content and radiation burden at different humidity was ascertained

  9. An electrochemical sensor for determining elemental iodine in gas media

    Goffman, V.G.; Shaimerdinov, B.U.; Kotelkin, I.M. [Institute of New Chemical Problems, Moscow (Russian Federation)] [and others

    1993-12-01

    The possibility of using solid-electrolyte Ag, AgI/AgI/Au cells as sensors for determining the concentration of elemental iodine in gas media is investigated. It is established that the sensor parameters are independent of oxygen content and radiation dose at different relative humidities.

  10. Oxygen configurations in silica

    Chelikowsky, James R.; Chadi, D. J.; Binggeli, N.

    2000-01-01

    We propose a transition state for oxygen in silica. This state is produced by the insertion of an oxygen molecule into the Si-O-Si bond, i.e., it consists of producing a Si-O-O-O-Si bond. This state allows molecular oxygen diffusion in silica without breaking the molecular O 2 bond and it is energetically more stable than a peroxy configuration. This configuration may allow for exchange of molecular oxygen with the oxygen in the silica framework. (c) 2000 The American Physical Society

  11. Monitoring bioremediation of weathered diesel NAPL using oxygen depletion profiles

    Davis, G.B.; Johnston, C.D.; Patterson, B.M.; Barber, C.; Bennett, M.

    1995-01-01

    Semicontinuous logging of oxygen concentrations at multiple depths has been used to evaluate the progress of an in situ bioremediation trial at a site contaminated by weathered diesel nonaqueous-phase liquid (NAPL). The evaluation trial consisted of periodic addition of nutrients and aeration of a 100-m 2 trial plot. During the bioremediation trial, aeration was stopped periodically, and decreases in dissolved and gaseous oxygen concentrations were monitored using data loggers attached to in situ oxygen sensors placed at multiple depths above and within a thin NAPL-contaminated zone. Oxygen usage rate coefficients were determined by fitting zero- and first-order rate equations to the oxygen depletion curves. For nutrient-amended sites within the trial plot, estimates of oxygen usage rate coefficients were significantly higher than estimates from unamended sites. These rates also converted to NPL degradation rates, comparable to those achieved in previous studies, despite the high concentrations and weathered state of the NAPL at this test site

  12. In situ quantification of ultra-low O2 concentrations in oxygen minimum zones

    Larsen, Morten; Lehner, Philipp; Borisov, Sergey M.

    2016-01-01

    based on the palladium(II)-benzoporphyrin luminophore, immobilized in a perfluorinated matrix with high O2 permeability. The trace sensor has a detection limit of ∼5 nmol L−1 with a dynamic range extending up to ∼2 μmol L−1. The sensor demonstrates a response time ..., and fully reversible response to hydrostatic pressure and temperature. The sensor showed excellent stability for continuously measurements during depth profiling in Oxygen Minimum Zones (OMZ). The novel sensor was deployed in situ using a Trace Oxygen Profiler instrument (TOP) equipped with two additional O...

  13. Nano-Enriched and Autonomous Sensing Framework for Dissolved Oxygen

    Nader Shehata

    2015-08-01

    Full Text Available This paper investigates a nano-enhanced wireless sensing framework for dissolved oxygen (DO. The system integrates a nanosensor that employs cerium oxide (ceria nanoparticles to monitor the concentration of DO in aqueous media via optical fluorescence quenching. We propose a comprehensive sensing framework with the nanosensor equipped with a digital interface where the sensor output is digitized and dispatched wirelessly to a trustworthy data collection and analysis framework for consolidation and information extraction. The proposed system collects and processes the sensor readings to provide clear indications about the current or the anticipated dissolved oxygen levels in the aqueous media.

  14. Nano-Enriched and Autonomous Sensing Framework for Dissolved Oxygen.

    Shehata, Nader; Azab, Mohammed; Kandas, Ishac; Meehan, Kathleen

    2015-08-14

    This paper investigates a nano-enhanced wireless sensing framework for dissolved oxygen (DO). The system integrates a nanosensor that employs cerium oxide (ceria) nanoparticles to monitor the concentration of DO in aqueous media via optical fluorescence quenching. We propose a comprehensive sensing framework with the nanosensor equipped with a digital interface where the sensor output is digitized and dispatched wirelessly to a trustworthy data collection and analysis framework for consolidation and information extraction. The proposed system collects and processes the sensor readings to provide clear indications about the current or the anticipated dissolved oxygen levels in the aqueous media.

  15. Microbial electrode sensor for alcohols

    Hikuma, M [Ajinomoto Co., Inc., Kawasaki, Japan; Kubo, T; Yasuda, T; Karube, I; Suzuki, S

    1979-10-01

    A microbial electrode consisting of immobilized microorganisms, a gas permeable Teflon membrane, and an oxygen electrode was prepared for the continuous determination of methyl and ethyl alcohols. Immobilized Trichosporon brassicae was employed for a microbial electrode sensor for ethyl alcohol. When a sample solution containing ethyl alcohol was injected into a microbial electrode system, the current of the electrode decreased markedly with time until a steady state was reached. The response time was within 10 min by the steady state method and within 6 min by the pulse method. A linear relationship was observed between the current decrease and the concentration of ethyl alcohol below 22.5 mg/liter. The current was reproducible within +- 6% of the relative error when a sample solution containing 16.5 mg/liter ethyl alcohol. The standard deviation was 0.5 mg/liter in 40 experiments. The selectivity of the microbial electrode sensor for ethyl alcohol was satisfactory. The microbial electrode sensor was applied to a fermentation broth of yeasts and satisfactory comparative results were obtained (correlation coefficient 0.98). The current output of the microbial electrode sensor was almost constant for more than three weeks and 2100 assays. A microbial electrode sensor using immobilized bacteria for methyl alcohol was also described.

  16. Improved fuel-cell-type hydrogen sensor

    Rudek, F. P.; Rutkowski, M. D.

    1968-01-01

    Modified hydrogen sensor replaces oxygen cathode with a cathode consisting of a sealed paste of gold hydroxide and a pure gold current collector. The net reaction which occurs during cell operation is the reduction of the gold hydroxide to gold and water, with a half-cell potential of 1.4 volts.

  17. Semiconductor sensors

    Hartmann, Frank

    2011-01-01

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

  18. Load sensor

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

    2007-01-01

    The invention relates to a load sensor comprising a polymer matrix and a piezo-ceramic material such as PZT, em not bedded in the polymer matrix, which together form a compos not ite, wherein the polymer matrix is a liquid crystalline resin, and wherein the piezo-ceramic material is a PZT powder forming 30-60% by volume of the composite, and wherein the PZT powder forms 40-50% by volume of the composite.

  19. Image Sensor

    Jerram, Paul; Stefanov, Konstantin

    2017-01-01

    An image sensor of the type for providing charge multiplication by impact ionisation has plurality of multiplication elements. Each element is arranged to receive charge from photosensitive elements of an image area and each element comprises a sequence of electrodes to move charge along a transport path. Each of the electrodes has an edge defining a boundary with a first electrode, a maximum width across the charge transport path and a leading edge that defines a boundary with a second elect...

  20. Optischer Sensor

    Brandenburg, A.; Fischer, A.

    1995-01-01

    An optical sensor (1) comprising an integrated optical arrangement has a waveguide (4) and at least one defraction grating (5) arranged in this waveguide. Light can launched into the waveguide via the defraction grating. In the reflection area of defraction grating, part of the light is dispersed through the waveguide at the beam angle for which the launch conditions and thus the defraction in the waveguide are fulfilled, so that, at this angle, a dark line (14) occurs whose position is evalu...

  1. Gas sensor

    Dorogan, V.; Korotchenkov, Gh.; Vieru, T.; Prodan, I.

    2003-01-01

    The invention relates to the gas sensors on base of metal-oxide films (SnO, InO), which may be used for enviromental control, in the fireextinguishing systema etc. The gas includes an insulating substrate, an active layer, a resistive layer with ohmic contacts. The resistive layer has two or more regions with dofferent resistances , and on the active layer are two or more pairs of ohmic contacts

  2. Interplay between O2 and SnO2: oxygen ionosorption and spectroscopic evidence for adsorbed oxygen.

    Gurlo, Alexander

    2006-10-13

    Tin dioxide is the most commonly used material in commercial gas sensors based on semiconducting metal oxides. Despite intensive efforts, the mechanism responsible for gas-sensing effects on SnO(2) is not fully understood. The key step is the understanding of the electronic response of SnO(2) in the presence of background oxygen. For a long time, oxygen interaction with SnO(2) has been treated within the framework of the "ionosorption theory". The adsorbed oxygen species have been regarded as free oxygen ions electrostatically stabilized on the surface (with no local chemical bond formation). A contradiction, however, arises when connecting this scenario to spectroscopic findings. Despite trying for a long time, there has not been any convincing spectroscopic evidence for "ionosorbed" oxygen species. Neither superoxide ions O(2)(-), nor charged atomic oxygen O,(-) nor peroxide ions O(2)(2-) have been observed on SnO(2) under the real working conditions of sensors. Moreover, several findings show that the superoxide ion does not undergo transformations into charged atomic oxygen at the surface, and represents a dead-end form of low-temperature oxygen adsorption on reduced metal oxide.

  3. Integrated turbomachine oxygen plant

    Anand, Ashok Kumar; DePuy, Richard Anthony; Muthaiah, Veerappan

    2014-06-17

    An integrated turbomachine oxygen plant includes a turbomachine and an air separation unit. One or more compressor pathways flow compressed air from a compressor through one or more of a combustor and a turbine expander to cool the combustor and/or the turbine expander. An air separation unit is operably connected to the one or more compressor pathways and is configured to separate the compressed air into oxygen and oxygen-depleted air. A method of air separation in an integrated turbomachine oxygen plant includes compressing a flow of air in a compressor of a turbomachine. The compressed flow of air is flowed through one or more of a combustor and a turbine expander of the turbomachine to cool the combustor and/or the turbine expander. The compressed flow of air is directed to an air separation unit and is separated into oxygen and oxygen-depleted air.

  4. Ambient oxygen promotes tumorigenesis.

    Ho Joong Sung

    2011-05-01

    Full Text Available Oxygen serves as an essential factor for oxidative stress, and it has been shown to be a mutagen in bacteria. While it is well established that ambient oxygen can also cause genomic instability in cultured mammalian cells, its effect on de novo tumorigenesis at the organismal level is unclear. Herein, by decreasing ambient oxygen exposure, we report a ∼50% increase in the median tumor-free survival time of p53-/- mice. In the thymus, reducing oxygen exposure decreased the levels of oxidative DNA damage and RAG recombinase, both of which are known to promote lymphomagenesis in p53-/- mice. Oxygen is further shown to be associated with genomic instability in two additional cancer models involving the APC tumor suppressor gene and chemical carcinogenesis. Together, these observations represent the first report directly testing the effect of ambient oxygen on de novo tumorigenesis and provide important physiologic evidence demonstrating its critical role in increasing genomic instability in vivo.

  5. Widespread functional anoxia in the oxygen minimum zone of the Eastern South Pacific

    Thamdrup, Bo; Dalsgaard, Tage; Revsbech, Niels Peter

    Oxygen minimum zones (OMZs) as found in the Eastern Pacific and Indian Ocean are biogeochemical hot spots with a disproportionately large role in the marine nitrogen cycle, and they are important components of the highly productive ecosystems in which they occur. Although the oxygen-depleted waters have been known for a century, oxygen levels inside them are not well constrained and the regulation of their anaerobic processes by oxygen is poorly understood. We deployed highly sensitive STOX oxygen sensors with a detection limit of 10 nmol kg-1 in combination with conventional hydrographic oxygen sensors along a cruise track transecting the Eastern South Pacific OMZ from South to North along the coast of Chile and Peru. Oxygen was below the detection limit throughout the ˜200 m thick OMZ core in most casts with STOX sensors. The only exception was an offshore location off Peru where oxygen was 10-50 nmol kg-1 in the core, likely as the result of a transient intrusion. Oxygen was also not detected in the OMZ core in further casts with conventional sensors, which had a detection limit of 90 nmol kg-1 after STOX-based zero calibration. Our measurements tighten the constraints on typical oxygen concentrations in the inner part of the OMZ by at least an order of magnitude relative to previous reports. Nitrite only accumulated when oxygen was depleted below 50 nmol kg-1, which indicates that nitrogen cycling is much more sensitive to oxygen than previously estimated. We argue that extreme oxygen depletion to low nanomalar or even picomolar concentrations is a normal condition in the South Pacific OMZ, and suggest that the OMZ core is in fact functionally anoxic over wide regions for extended periods. Our results further indicate that oxygen dynamics in the low nanomolar range play an important role in OMZ biogeochemistry.

  6. Use of Optical Oxygen Sensors in Non-Destructively Determining the Levels of Oxygen Present in Combined Vacuum and Modified Atmosphere Packaged Pre-Cooked Convenience-Style Foods and the Use of Ethanol Emitters to Extend Product Shelf-Life

    Andreas W. Hempel

    2013-11-01

    Full Text Available O2 sensors were used to non-destructively monitor O2 levels in commercially packed pre-cooked, convenience modified atmosphere packaging (MAP foods. A substantial level of O2 (>15% was present in packs resulting in a shorter than expected shelf-life, where the primary spoilage mechanism was found to be mould. Various combinations of vacuum (0–0.6 MPa and gas flush (0.02–0.03 MPa (30% CO2/70% N2 settings were assessed as treatments that result in the desired shelf-life (28 days. This was achieved using the combined treatment of vacuum 0.35 MPa and gas flush 0.02 MPa which resulted in a reduction of 6%–9% O2 in all three samples (battered sausages (BS, bacon slices (BA, and meat and potato pies (PP. Reduced O2 levels reflect the microbial quality of products, which has been successfully reduced. Duplicate samples of all product packs were produced using ethanol emitters (EE to see if shelf-life could be further extended. Results showed a further improvement in shelf-life to 35 days. Sensory analysis showed that ethanol flavour and aroma was not perceived by panellists in two of the three products assessed. This study demonstrates how smart packaging technologies, both intelligent and active, can be used to assist in the modification of conventional packaging systems in order to enhance product quality and safety and through the extension of product shelf-life.

  7. Oxygen defect processes in silicon and silicon germanium

    Chroneos, A.; Sgourou, E. N.; Londos, C. A.; Schwingenschlö gl, Udo

    2015-01-01

    Silicon and silicon germanium are the archetypical elemental and alloy semiconductor materials for nanoelectronic, sensor, and photovoltaic applications. The investigation of radiation induced defects involving oxygen, carbon, and intrinsic defects is important for the improvement of devices as these defects can have a deleterious impact on the properties of silicon and silicon germanium. In the present review, we mainly focus on oxygen-related defects and the impact of isovalent doping on their properties in silicon and silicon germanium. The efficacy of the isovalent doping strategies to constrain the oxygen-related defects is discussed in view of recent infrared spectroscopy and density functional theory studies.

  8. Oxygen defect processes in silicon and silicon germanium

    Chroneos, A.

    2015-06-18

    Silicon and silicon germanium are the archetypical elemental and alloy semiconductor materials for nanoelectronic, sensor, and photovoltaic applications. The investigation of radiation induced defects involving oxygen, carbon, and intrinsic defects is important for the improvement of devices as these defects can have a deleterious impact on the properties of silicon and silicon germanium. In the present review, we mainly focus on oxygen-related defects and the impact of isovalent doping on their properties in silicon and silicon germanium. The efficacy of the isovalent doping strategies to constrain the oxygen-related defects is discussed in view of recent infrared spectroscopy and density functional theory studies.

  9. Intrusion detection sensors

    Williams, J.D.

    1978-07-01

    Intrusion detection sensors are an integral part of most physical security systems. Under the sponsorship of the U.S. Department of Energy, Office of Safeguards and Security, Sandia Laboratories has conducted a survey of available intrusion detection sensors and has tested a number of different sensors. An overview of these sensors is provided. This overview includes (1) the operating principles of each type of sensor, (2) unique sensor characteristics, (3) desired sensor improvements which must be considered in planning an intrusion detection system, and (4) the site characteristics which affect the performance of both exterior and interior sensors. Techniques which have been developed to evaluate various intrusion detection sensors are also discussed

  10. Chemical Gas Sensors for Aeronautic and Space Applications

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

    1997-01-01

    Aeronautic and space applications require the development of chemical sensors with capabilities beyond those of commercially available sensors. Two areas of particular interest are safety monitoring and emission monitoring. In safety monitoring, detection of low concentrations of hydrogen at potentially low temperatures is important while for emission monitoring the detection of nitrogen oxides, hydrogen, hydrocarbons and oxygen is of interest. This paper discusses the needs of aeronautic and space applications and the point-contact sensor technology being developed to address these needs. The development of these sensors is based on progress in two types of technology: (1) Micromachining and microfabrication technology to fabricate miniaturized sensors. (2) The development of high temperature semiconductors, especially silicon carbide. The detection of each type of gas involves its own challenges in the fields of materials science and fabrication technology. The number of dual-use commercial applications of this microfabricated gas sensor technology make this general area of sensor development a field of significant interest.

  11. Zirconia-based solid state chemical gas sensors

    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

  12. Hydrogen sensor

    Duan, Yixiang; Jia, Quanxi; Cao, Wenqing

    2010-11-23

    A hydrogen sensor for detecting/quantitating hydrogen and hydrogen isotopes includes a sampling line and a microplasma generator that excites hydrogen from a gas sample and produces light emission from excited hydrogen. A power supply provides power to the microplasma generator, and a spectrometer generates an emission spectrum from the light emission. A programmable computer is adapted for determining whether or not the gas sample includes hydrogen, and for quantitating the amount of hydrogen and/or hydrogen isotopes are present in the gas sample.

  13. Oxygen enrichment incineration

    Kim, Jeong Guk; Yang, Hee Chul; Park, Geun Il; Kim, Joon Hyung

    2000-10-01

    Oxygen enriched combustion technology has recently been used in waste incineration. To apply the oxygen enrichment on alpha-bearing waste incineration, which is being developed, a state-of-an-art review has been performed. The use of oxygen or oxygen-enriched air instead of air in incineration would result in increase of combustion efficiency and capacity, and reduction of off-gas product. Especially, the off-gas could be reduced below a quarter, which might reduce off-gas treatment facilities, and also increase an efficiency of off-gas treatment. However, the use of oxygen might also lead to local overheating and high nitrogen oxides (NOx) formation. To overcome these problems, an application of low NOx oxy-fuel burner and recycling of a part of off-gas to combustion chamber have been suggested

  14. Oxygen enrichment incineration

    Kim, Jeong Guk; Yang, Hee Chul; Park, Geun Il; Kim, Joon Hyung

    2000-10-01

    Oxygen enriched combustion technology has recently been used in waste incineration. To apply the oxygen enrichment on alpha-bearing waste incineration, which is being developed, a state-of-an-art review has been performed. The use of oxygen or oxygen-enriched air instead of air in incineration would result in increase of combustion efficiency and capacity, and reduction of off-gas product. Especially, the off-gas could be reduced below a quarter, which might reduce off-gas treatment facilities, and also increase an efficiency of off-gas treatment. However, the use of oxygen might also lead to local overheating and high nitrogen oxides (NOx) formation. To overcome these problems, an application of low NOx oxy-fuel burner and recycling of a part of off-gas to combustion chamber have been suggested.

  15. Sensors for Entertainment.

    Lamberti, Fabrizio; Sanna, Andrea; Rokne, Jon

    2016-07-15

    Sensors are becoming ubiquitous in all areas of science, technology, and society. In this Special Issue on "Sensors for Entertainment", developments in progress and the current state of application scenarios for sensors in the field of entertainment is explored.

  16. Sensors for Entertainment

    Fabrizio Lamberti; Andrea Sanna; Jon Rokne

    2016-01-01

    Sensors are becoming ubiquitous in all areas of science, technology, and society. In this Special Issue on ?Sensors for Entertainment?, developments in progress and the current state of application scenarios for sensors in the field of entertainment is explored.

  17. Oxygen Transfer Model for a Flow-Through Hollow-Fiber Membrane Biofilm Reactor

    Gilmore, K. R.; Little, J. C.; Smets, Barth F.

    2009-01-01

    overpredicted the oxygen transfer by a factor of 1.3 relative to the result calculated from the outlet gas oxygen concentration, which was considered the most accurate of the measured benchmarks. A mass transfer coefficient derived from the clean water testing with oxygen sensors at the membrane......-liquid interface was the most accurate of the predictive models (overpredicted by a factor of 1.1) while a coefficient determined by measuring bulk liquid dissolved oxygen underpredicted the oxygen transfer by a factor of 3. The mechanistic model was found to be an adequate tool for design because it used...

  18. A new inexpensive electrochemical meter for oxygen in sodium coolant

    Periaswami, G.; Rajan Babu, S.S.; Mathews, C.K.

    1987-01-01

    This report describes the development of an inexpensive oxygen meter for sodium coolant and gives the results of the test experiments. Calcia stabilized zirconia has been found to have necessary domain boundary characteristics at low temperatures for use as oxygen sensor in liquid sodium system. It is possible to obtain acceptable sensor cell resistance at temperatures as low as 230 C if K, K 2 O or Na, Na 2 O is used as reference electrode. The performance of these cells has been tested in bench top sodium loops over long periods. Their performance in terms of cell-out put variation with change in oxygen concentration in sodium has been found to be satisfactory. They also have sufficiently long life times since the kinetics of sodium attack on the electrolyte is slow at low temperatures. (author). 17 refs., 6 figs

  19. Wireless sensor platform

    Joshi, Pooran C.; Killough, Stephen M.; Kuruganti, Phani Teja

    2017-08-08

    A wireless sensor platform and methods of manufacture are provided. The platform involves providing a plurality of wireless sensors, where each of the sensors is fabricated on flexible substrates using printing techniques and low temperature curing. Each of the sensors can include planar sensor elements and planar antennas defined using the printing and curing. Further, each of the sensors can include a communications system configured to encode the data from the sensors into a spread spectrum code sequence that is transmitted to a central computer(s) for use in monitoring an area associated with the sensors.

  20. High Selectivity Oxygen Delignification

    Lucian A. Lucia

    2005-11-15

    Project Objective: The objectives of this project are as follows: (1) Examine the physical and chemical characteristics of a partner mill pre- and post-oxygen delignified pulp and compare them to lab generated oxygen delignified pulps; (2) Apply the chemical selectivity enhancement system to the partner pre-oxygen delignified pulps under mill conditions (with and without any predetermined amounts of carryover) to determine how efficiently viscosity is preserved, how well selectivity is enhanced, if strength is improved, measure any yield differences and/or bleachability differences; and (3) Initiate a mill scale oxygen delignification run using the selectivity enhancement agent, collect the mill data, analyze it, and propose any future plans for implementation.

  1. Optic nerve oxygenation

    Stefánsson, Einar; Pedersen, Daniella Bach; Jensen, Peter Koch

    2005-01-01

    The oxygen tension of the optic nerve is regulated by the intraocular pressure and systemic blood pressure, the resistance in the blood vessels and oxygen consumption of the tissue. The oxygen tension is autoregulated and moderate changes in intraocular pressure or blood pressure do not affect...... the optic nerve oxygen tension. If the intraocular pressure is increased above 40 mmHg or the ocular perfusion pressure decreased below 50 mmHg the autoregulation is overwhelmed and the optic nerve becomes hypoxic. A disturbance in oxidative metabolism in the cytochromes of the optic nerve can be seen...... at similar levels of perfusion pressure. The levels of perfusion pressure that lead to optic nerve hypoxia in the laboratory correspond remarkably well to the levels that increase the risk of glaucomatous optic nerve atrophy in human glaucoma patients. The risk for progressive optic nerve atrophy in human...

  2. Pathology of oxygen

    Autor, Anne Pomeroy

    1982-01-01

    This volume has been designed to provide those interested in oxygen toxicity with a working knowledge of advancement in the field with the intention that the topics described in each chapter will be immediately useful...

  3. Using oxygen at home

    ... at Home Tell your local fire department, electric company, and telephone company that you use oxygen in your home. They ... M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health ...

  4. Pathology of oxygen

    Autor, Anne Pomeroy

    1982-01-01

    .... The book is divided into three general sections. The first and smallest section of the book explains the molecular and biochemical basis of our current understanding of oxygen radical toxicity as well as the means by which normal aerobic cells...

  5. Abnormal gas sensing characteristics arising from catalyzed morphological changes of ionsorbed oxygen

    Xue Xinyu; Chen Zhaohui; Ma Chunhua; Xing Lili; Chen Yujin; Wang Yanguo; Wang Taihong

    2010-01-01

    Abnormal gas sensing characteristics are observed at low temperature in uniformly loaded Pt-SnO 2 nanorod gas sensors. The sensors operated at 200 deg. C exhibit opposite variations of resistances, and the change of resistance decreases with increasing ethanol concentration. In contrast, the sensors operated at 300 deg. C show regular behavior and the sensitivity is extremely high. Such behaviors are ascribed to Pt-catalyzed morphological changes of ionsorbed oxygen at low temperature. The present results are the bases for further investigating the effect of ionsorbed oxygen morphologies on gas sensing.

  6. Optic nerve oxygen tension

    la Cour, M; Kiilgaard, Jens Folke; Eysteinsson, T

    2000-01-01

    To investigate the influence of acute changes in intraocular pressure on the oxygen tension in the vicinity of the optic nerve head under control conditions and after intravenous administration of 500 mg of the carbonic anhydrase inhibitor dorzolamide.......To investigate the influence of acute changes in intraocular pressure on the oxygen tension in the vicinity of the optic nerve head under control conditions and after intravenous administration of 500 mg of the carbonic anhydrase inhibitor dorzolamide....

  7. Ekstrakorporal oxygenering ved legionellapneumoni

    Uslu, Bülent; Steensen, Morten

    2009-01-01

    We present a case report with a 49-year-old woman with legionella pneumonia and fulminant respiratory failure. Despite maximal conventional respirator treatment with positive pressure ventilation, 100% oxygen and pharmacological treatment in an intensive care unit, further deterioration with hypo......We present a case report with a 49-year-old woman with legionella pneumonia and fulminant respiratory failure. Despite maximal conventional respirator treatment with positive pressure ventilation, 100% oxygen and pharmacological treatment in an intensive care unit, further deterioration...

  8. Intraportal islet oxygenation.

    Suszynski, Thomas M; Avgoustiniatos, Efstathios S; Papas, Klearchos K

    2014-05-01

    Islet transplantation (IT) is a promising therapy for the treatment of diabetes. The large number of islets required to achieve insulin independence limit its cost-effectiveness and the number of patients who can be treated. It is believed that >50% of islets are lost in the immediate post-IT period. Poor oxygenation in the early post-IT period is recognized as a possible reason for islet loss and dysfunction but has not been extensively studied. Several key variables affect oxygenation in this setting, including (1) local oxygen partial pressure (pO(2)), (2) islet oxygen consumption, (3) islet size (diameter, D), and (4) presence or absence of thrombosis on the islet surface. We discuss implications of oxygen-limiting conditions on intraportal islet viability and function. Of the 4 key variables, the islet size appears to be the most important determinant of the anoxic and nonfunctional islet volume fractions. Similarly, the effect of thrombus formation on the islet surface may be substantial. At the University of Minnesota, average size distribution data from clinical alloislet preparations (n = 10) indicate that >150-µm D islets account for only ~30% of the total islet number, but >85% of the total islet volume. This suggests that improved oxygen supply to the islets may have a profound impact on islet survivability and function since most of the β-cell volume is within large islets which are most susceptible to oxygen-limiting conditions. The assumption that the liver is a suitable islet transplant site from the standpoint of oxygenation should be reconsidered. © 2014 Diabetes Technology Society.

  9. A modular optical sensor

    Conklin, John Albert

    This dissertation presents the design of a modular, fiber-optic sensor and the results obtained from testing the modular sensor. The modular fiber-optic sensor is constructed in such manner that the sensor diaphragm can be replaced with different configurations to detect numerous physical phenomena. Additionally, different fiber-optic detection systems can be attached to the sensor. Initially, the modular sensor was developed to be used by university of students to investigate realistic optical sensors and detection systems to prepare for advance studies of micro-optical mechanical systems (MOMS). The design accomplishes this by doing two things. First, the design significantly lowers the costs associated with studying optical sensors by modularizing the sensor design. Second, the sensor broadens the number of physical phenomena that students can apply optical sensing techniques to in a fiber optics sensor course. The dissertation is divided into seven chapters covering the historical development of fiber-optic sensors, a theoretical overview of fiber-optic sensors, the design, fabrication, and the testing of the modular sensor developed in the course of this work. Chapter 1 discusses, in detail, how this dissertation is organized and states the purpose of the dissertation. Chapter 2 presents an historical overview of the development of optical fibers, optical pressure sensors, and fibers, optical pressure sensors, and optical microphones. Chapter 3 reviews the theory of multi-fiber optic detection systems, optical microphones, and pressure sensors. Chapter 4 presents the design details of the modular, optical sensor. Chapter 5 delves into how the modular sensor is fabricated and how the detection systems are constructed. Chapter 6 presents the data collected from the microphone and pressure sensor configurations of the modular sensor. Finally, Chapter 7 discusses the data collected and draws conclusions about the design based on the data collected. Chapter 7 also

  10. Singlet oxygen quenching by oxygen in tetraphenyl-porphyrin solutions

    Dedic, Roman; Korinek, Miloslav; Molnar, Alexander; Svoboda, Antonin; Hala, Jan

    2006-01-01

    Time-resolved measurement of singlet oxygen infrared phosphorescence is a powerful tool for determination of quantum yields and kinetics of its photosensitization. This technique was employed to investigate in detail the previously observed effect of singlet oxygen quenching by oxygen. The question whether the singlet oxygen is quenched by oxygen in ground or in excited state was addressed by study of two complementary dependencies of singlet oxygen lifetimes: on dissolved oxygen concentration and on excitation intensity. Oxygen concentration dependence study of meso-tetra(4-sulphonato)phenylporphyrin (TPPS 4 ) phosphorescence kinetics showed linearity of the dependence of TPPS 4 triplet state rate-constant. Corresponding bimolecular quenching constant of (1.5±0.1)x10 9 l/mol s was obtained. On the other hand, rate constants of singlet oxygen depopulation exhibit nonlinear dependence on oxygen concentration. Comparison of zero oxygen concentration-extrapolated value of singlet oxygen lifetime of (6.5±0.4) μs to (3.7±0.1) μs observed under air-saturated conditions indicates importance of the effect of quenching of singlet oxygen by oxygen. Upward-sloping dependencies of singlet oxygen depopulation rate-constant on excitation intensity evidence that singlet oxygen is predominantly quenched by oxygen in excited singlet state

  11. Deposition of sol-gel sensor spots by nanoimprint lithography and hemi-wicking

    Mikkelsen, Morten Bo Lindholm; Marie, Rodolphe; Hansen, Jan H.

    2011-01-01

    We present a method for homogeneous deposition of sol-gel sensor materials, which enable fabrication of sensor spots for optical pH and oxygen measurements inside plastic containers. A periodic pattern of posts is imprinted into a polycarbonate substrate and, using the principle of hemi-wicking, ......We present a method for homogeneous deposition of sol-gel sensor materials, which enable fabrication of sensor spots for optical pH and oxygen measurements inside plastic containers. A periodic pattern of posts is imprinted into a polycarbonate substrate and, using the principle of hemi...

  12. Color Changing Hydrogen Sensors

    Roberson, Luke B.; Williams, Martha; Captain, Janine E.; Mohajeri, Nahid; Raissi, Ali

    2015-01-01

    During the Space Shuttle Program, one of the most hazardous operation that occurred was the loading of liquid hydrogen (LH2) during fueling operations of the spacecraft. Due to hydrogen's low explosive limit, any amount leaked could lead to catastrophic event. Hydrogen's chemical properties make it ideal as a rocket fuel; however, the fuel is deemed unsafe for most commercial use because of the inability to easily detect the gas leaking. The increased use of hydrogen over traditional fossil fuels would reduce greenhouse gases and America's dependency on foreign oil. Therefore a technology that would improve safety at NASA and in the commercial sector while creating a new economic sector would have a huge impact to NASA's mission. The Chemochromic Detector for sensing hydrogen gas leakage is a color-changing detector that is useful in any application where it is important to know not only the presence but also the location of the hydrogen gas leak. This technology utilizes a chemochromicpigment and polymer matrix that can be molded or spun into rigid or pliable shapes useable in variable temperature environments including atmospheres of inert gas, hydrogen gas, or mixtures of gases. A change in color of the detector material indicates where gaseous hydrogen leaks are occurring. The irreversible sensor has a dramatic color change from beige to dark grey and remains dark grey after exposure. A reversible pigment changes from white to blue in the presence of hydrogen and reverts back to white in the presence of oxygen. Both versions of the sensor's pigments were comprised of a mixture of a metal oxide substrate and a hydro-chromic compound (i.e., the compound that changed color in the presence of hydrogen) and immediately notified the operator of the presence of low levels of hydrogen. The detector can be used in a variety of formats including paint, tape, caulking, injection molded parts, textiles and fabrics, composites, and films. This technology brings numerous

  13. Oxygen optical gas sensing by reversible fluorescence quenching in photo-oxidized poly(9,9-dioctylfluorene) thin films.

    Anni, M; Rella, R

    2010-02-04

    We investigated the fluorescence (FL) dependence on the environment oxygen content of poly(9,9-dioctylfluorene) (PF8) thin films. We show that the PF8 interactions with oxygen are not limited to the known irreversible photo-oxidation, resulting in the formation of Keto defects, but also reversible FL quenching is observed. This effect, which is stronger for the Keto defects than for the PF8, has been exploited for the realization of a prototype oxygen sensor based on FL quenching. The sensing sensitivity of Keto defects is comparable with the state of the art organic oxygen sensors based on phosphorescence quenching.

  14. Integrated cryogenic sensors

    Juanarena, D.B.; Rao, M.G.

    1991-01-01

    Integrated cryogenic pressure-temperature, level-temperature, and flow-temperature sensors have several advantages over the conventional single parameter sensors. Such integrated sensors were not available until recently. Pressure Systems, Inc. (PSI) of Hampton, Virginia, has introduced precalibrated precision cryogenic pressure sensors at the Los Angeles Cryogenic Engineering Conference in 1989. Recently, PSI has successfully completed the development of integrated pressure-temperature and level-temperature sensors for use in the temperature range 1.5-375K. In this paper, performance characteristics of these integrated sensors are presented. Further, the effects of irradiation and magnetic fields on these integrated sensors are also reviewed

  15. EDITORIAL: Humidity sensors Humidity sensors

    Regtien, Paul P. L.

    2012-01-01

    produced at relatively low cost. Therefore, they find wide use in lots of applications. However, the method requires a material that possesses some conflicting properties: stable and reproducible relations between air humidity, moisture uptake and a specific property (for instance the length of a hair, the electrical impedance of the material), fast absorption and desorption of the water vapour (to obtain a short response time), small hysteresis, wide range of relative humidity (RH) and temperature-independent output (only responsive to RH). For these reasons, much research is done and is still going on to find suitable materials that combine high performance and low price. In this special feature, three of the four papers report on absorption sensors, all with different focus. Aziz et al describe experiments with newly developed materials. The surface structure is extensively studied, in view of its ability to rapidly absorb water vapour and exhibit a reproducible change in the resistance and capacitance of the device. Sanchez et al employ optical fibres coated with a thin moisture-absorbing layer as a sensitive humidity sensor. They have studied various coating materials and investigated the possibility of using changes in optical properties of the fibre (here the lossy mode resonance) due to a change in humidity of the surrounding air. The third paper, by Weremczuk et al, focuses on a cheap fabrication method for absorption-based humidity sensors. The inkjet technology appears to be suitable for mass fabrication of such sensors, which is demonstrated by extensive measurements of the electrical properties (resistance and capacitance) of the absorbing layers. Moreover, they have developed a model that describes the relation between humidity and the electrical parameters of the moisture-sensitive layer. Despite intensive research, absorption sensors still do not meet the requirements for high accuracy applications. The dew-point temperature method is more appropriate

  16. Submersible microbial fuel cell sensor for monitoring microbial activity and BOD in groundwater: Focusing on impact of anodic biofilm on sensor applicability

    Zhang, Yifeng; Angelidaki, Irini

    2011-01-01

    was required for application of the sensor for microbial activity measurement, while biofilm‐colonized anode was needed for utilizing the sensor for BOD content measurement. The current density of SUMFC sensor equipped with a biofilm‐colonized anode showed linear relationship with BOD content, to up to 250 mg......A sensor, based on a submersible microbial fuel cell (SUMFC), was developed for in situ monitoring of microbial activity and biochemical oxygen demand (BOD) in groundwater. Presence or absence of a biofilm on the anode was a decisive factor for the applicability of the sensor. Fresh anode...

  17. Net community production from autonomous oxygen observations in the Sargasso Sea

    Feen, M.; Estapa, M. L.

    2016-02-01

    Optical sensors on autonomous floats provide high-resolution profiles of oxygen concentration over time. Improved spatiotemporal resolution in our measurements of oxygen will allow for better estimates of net community production and a greater understanding of the biological pump. Two autonomous profiling floats (NAVIS BGCi, Sea-Bird) equipped with SBE-63 optodes to measure dissolved oxygen were deployed in the Sargasso Sea on a series of five Bermuda Atlantic Time-series Study (BATS) cruises from July 2013 to April 2014. In situ calibration of the oxygen sensors to Winkler titration bottle samples at BATS did not show systematic drift in the oxygen sensors over time. Calibrations were applied to determine oxygen concentrations in profiles collected in the Sargasso Sea at 1.5 to 2.5 day intervals over a year. Oxygen concentrations were used to quantify sub-mixed layer net community production. Changes in production rates from this study were compared with upper water column biology and particle flux measurements obtained independently from optical sensors on the profiling floats, allowing us to examine processes controlling carbon export into the deep ocean.

  18. Closed Loop Control of Oxygen Delivery and Oxygen Generation

    2017-08-01

    were used for this study and were connected via a USB cable to allow communication. The ventilator was modified to allow closed loop control of oxygen...connected via a USB cable to allow communication. The ventilator was modified to allow closed loop control of oxygen based on the oxygen saturation...2017-4119, 28 Aug 2017. oximetry (SpO2) and intermittent arterial blood sampling for arterial oxygen tension (partial pressure of oxygen [PaO2]) and

  19. Oxygen measurement by multimode diode lasers employing gas correlation spectroscopy.

    Lou, Xiutao; Somesfalean, Gabriel; Chen, Bin; Zhang, Zhiguo

    2009-02-10

    Multimode diode laser (MDL)-based correlation spectroscopy (COSPEC) was used to measure oxygen in ambient air, thereby employing a diode laser (DL) having an emission spectrum that overlaps the oxygen absorption lines of the A band. A sensitivity of 700 ppm m was achieved with good accuracy (2%) and linearity (R(2)=0.999). For comparison, measurements of ambient oxygen were also performed by tunable DL absorption spectroscopy (TDLAS) technique employing a vertical cavity surface emitting laser. We demonstrate that, despite slightly degraded sensitivity, the MDL-based COSPEC-based oxygen sensor has the advantages of high stability, low cost, ease-of-use, and relaxed requirements in component selection and instrument buildup compared with the TDLAS-based instrument.

  20. Staying alive! Sensors used for monitoring cell health in bioreactors.

    O'Mara, P; Farrell, A; Bones, J; Twomey, K

    2018-01-01

    Current and next generation sensors such as pH, dissolved oxygen (dO) and temperature sensors that will help drive the use of single-use bioreactors in industry are reviewed. The current trend in bioreactor use is shifting from the traditional fixed bioreactors to the use of single-use bioreactors (SUBs). However as the shift in paradigm occurs there is now a greater need for sensor technology to play 'catch up' with the innovation of bioreactor technology. Many of the sensors still in use today rely on technology created in the 1960's such as the Clark-type dissolved oxygen sensor or glass pH electrodes. This is due to the strict requirements of sensors to monitor bioprocesses resulting in the use of traditional well understood methods, making it difficult to incorporate new sensor technology into industry. A number of advances in sensor technology have been achieved in recent years, a few of these advances and future research will also be discussed in this review. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Quasi-distributed sol-gel coated fiber optic oxygen sensing probe

    Zolkapli, Maizatul; Saharudin, Suhairi; Herman, Sukreen Hana; Abdullah, Wan Fazlida Hanim

    2018-03-01

    In the field of aquaculture, optical sensor technology is beginning to provide alternatives to the conventional electrical sensor. Hence, the development and characterization of a multipoint quasi-distributed optical fiber sensor for oxygen measurement is reported. The system is based on 1 mm core diameter plastic optical fiber where sections of cladding have been removed and replaced with three metal complexes sol-gel films to form sensing points. The sensing locations utilize luminophores that have emission peaks at 385 nm, 405 nm and 465 nm which associated with each of the sensing points. Interrogation of the optical sensor system is through a fiber optic spectrometer incorporating narrow bandpass emission optical filter. The sensors showed comparable sensitivity and repeatability, as well as fast response and recovery towards oxygen.

  2. Oxygen Dependent Biocatalytic Processes

    Pedersen, Asbjørn Toftgaard

    Enzyme catalysts have the potential to improve both the process economics and the environ-mental profile of many oxidation reactions especially in the fine- and specialty-chemical industry, due to their exquisite ability to perform stereo-, regio- and chemo-selective oxida-tions at ambient...... to aldehydes and ketones, oxyfunctionalization of C-H bonds, and epoxidation of C-C double bonds. Although oxygen dependent biocatalysis offers many possibilities, there are numerous chal-lenges to be overcome before an enzyme can be implemented in an industrial process. These challenges requires the combined...... far below their potential maximum catalytic rate at industrially relevant oxygen concentrations. Detailed knowledge of the en-zyme kinetics are therefore required in order to determine the best operating conditions and design oxygen supply to minimize processing costs. This is enabled...

  3. Oxygen therapy reduces postoperative tachycardia

    Stausholm, K; Kehlet, H; Rosenberg, J

    1995-01-01

    Concomitant hypoxaemia and tachycardia in the postoperative period is unfavourable for the myocardium. Since hypoxaemia per se may be involved in the pathogenesis of postoperative tachycardia, we have studied the effect of oxygen therapy on tachycardia in 12 patients randomly allocated to blinded...... air or oxygen by facemask on the second or third day after major surgery. Inclusion criteria were arterial hypoxaemia (oxygen saturation 90 beat.min-1). Each patient responded similarly to oxygen therapy: an increase in arterial oxygen saturation and a decrease...... in heart rate (p oxygen has a positive effect on the cardiac oxygen delivery and demand balance....

  4. Hyperbaric oxygen and radiotherapy

    Mayer, R.; Hamilton-Farrell, M.R.; Kleij, A.J. van der

    2005-01-01

    Background: Hyperbaric oxygen (HBO) therapy is the inhalation of 100% oxygen at a pressure of at least 1.5 atmospheres absolute (150 kPa). It uses oxygen as a drug by dissolving it in the plasma and delivering it to the tissues independent of hemoglobin. For a variety of organ systems, HBO is known to promote new vessel growth into areas with reduced oxygen tension due to poor vascularity, and therewith promotes wound healing and recovery of radiation-injured tissue. Furthermore, tumors may be sensitized to irradiation by raising intratumoral oxygen tensions. Methods: A network of hyperbaric facilities exists in Europe, and a number of clinical studies are ongoing. The intergovernmental framework COST B14 action 'Hyperbaric Oxygen Therapy' started in 1999. The main goal of the Working Group Oncology is preparation and actual implementation of prospective study protocols in the field of HBO and radiation oncology in Europe. Results: In this paper a short overview on HBO is given and the following randomized clinical studies are presented: (a) reirradiation of recurrent squamous cell carcinoma of the head and neck after HBO sensitization; (b) role of HBO in enhancing radiosensitivity on glioblastoma multiforme; (c) osseointegration in irradiated patients; adjunctive HBO to prevent implant failures; (d) the role of HBO in the treatment of late irradiation sequelae in the pelvic region. The two radiosensitization protocols (a, b) allow a time interval between HBO and subsequent irradiation of 10-20 min. Conclusion: Recruitment of centers and patients is being strongly encouraged, detailed information is given on www.oxynet.org. (orig.)

  5. HOPG/ZnO/HOPG pressure sensor

    Jahangiri, Mojtaba; Yousefiazari, Ehsan; Ghalamboran, Milad

    2017-12-01

    Pressure sensor is one of the most commonly used sensors in the research laboratories and industries. These are generally categorized in three different classes of absolute pressure sensors, gauge pressure sensors, and differential pressure sensors. In this paper, we fabricate and assess the pressure sensitivity of the current vs. voltage diagrams in a graphite/ZnO/graphite structure. Zinc oxide layers are deposited on highly oriented pyrolytic graphite (HOPG) substrates by sputtering a zinc target under oxygen plasma. The top electrode is also a slice of HOPG which is placed on the ZnO layer and connected to the outside electronic circuits. By recording the I-V characteristics of the device under different forces applied to the top HOPG electrode, the pressure sensitivity is demonstrated; at the optimum biasing voltage, the device current changes 10 times upon changing the pressure level on the top electrode by 20 times. Repeatability and reproducibility of the observed effect is studied on the same and different samples. All the materials used for the fabrication of this pressure sensor are biocompatible, the fabricated device is anticipated to find potential applications in biomedical engineering.

  6. OXYGEN MANAGEMENT DURING ALCOHOLIC FERMENTATION

    MOENNE VARGAS, MARÍA ISABE

    2013-01-01

    Oxygen additions are a common practice in winemaking, as oxygen has a positive effect in fermentative kinetics, biomass synthesis and improvement of color, structure and :flavor in treated wines. However, most oxygen additions are carried out heuristically through pump-over operations solely on a know-how basis, which is difficult to manage in terms of the exact quantity of oxygen transferred to the fermenting must. It is important to estímate the amount of oxygen added because...

  7. Terahertz Quantum Cascade Laser-Based Sensors for Hypersonic Flows (7275-020), Phase II

    National Aeronautics and Space Administration — Physical Sciences Inc. (PSI) proposes to design, build, test, and deliver to NASA a THz wavelength absorption sensor for continuous monitoring of atomic oxygen...

  8. Diode Laser-Based Sensor for Fast Measurement of Binary Gas Mixtures

    McNesby, Kevin

    1999-01-01

    The development and characterization of a gas sensor to measure binary mixtures of oxygen and the vapor from a series of volatile organic compounds, with a time resolution of 10 milliseconds, is described...

  9. Application Of FA Sensor 2

    Park, Seon Ho

    1993-03-01

    This book introduces FA sensor from basic to making system, which includes light sensor like photo diode and photo transistor, photo electricity sensor, CCD type image sensor, MOS type image sensor, color sensor, cds cell, and optical fiber scope. It also deals with direct election position sensor such as proximity switch, differential motion, linear scale of photo electricity type, and magnet scale, rotary sensor with summary of rotary encoder, rotary encoder types and applications, flow sensor, and sensing technology.

  10. Space Shuttle Orbiter oxygen partial pressure sensing and control system improvements

    Frampton, Robert F.; Hoy, Dennis M.; Kelly, Kevin J.; Walleshauser, James J.

    1992-01-01

    A program aimed at developing a new PPO2 oxygen sensor and a replacement amplifier for the Space Shuttle Orbiter is described. Experimental design methodologies used in the test and modeling process made it possible to enhance the effectiveness of the program and to reduce its cost. Significant cost savings are due to the increased lifetime of the basic sensor cell, the maximization of useful sensor life through an increased amplifier gain adjustment capability, the use of streamlined production processes for the manufacture of the assemblies, and the refurbishment capability of the replacement sensor.

  11. Sensors an introductory course

    Kalantar-zadeh, Kourosh

    2013-01-01

    Sensors: An Introductory Course provides an essential reference on the fundamentals of sensors. The book is designed to help readers in developing skills and the understanding required in order to implement a wide range of sensors that are commonly used in our daily lives. This book covers the basic concepts in the sensors field, including definitions and terminologies. The physical sensing effects are described, and devices which utilize these effects are presented. The most frequently used organic and inorganic sensors are introduced and the techniques for implementing them are discussed. This book: Provides a comprehensive representation of the most common sensors and can be used as a reference in relevant fields Presents learning materials in a concise and easy to understand manner Includes examples of how sensors are incorporated in real life measurements Contains detailed figures and schematics to assist in understanding the sensor performance Sensors: An Introductory Course is ideal for university stu...

  12. Coupled wave sensor technology

    Maki, M.C.

    1988-01-01

    Buried line guided radar sensors have been used successfully for a number of years to provide perimeter security for high value resources. This paper introduces a new complementary sensor advancement at Computing Devices termed 'coupled wave device technology' (CWD). It provides many of the inherent advantages of leakey cable sensors, such as terrain-following and the ability to discriminate between humans and small animals. It also is able to provide a high or wide detection zone, and allows the sensor to be mounted aerially and adjacent to a wall or fence. Several alternative sensors have been developed which include a single-line sensor, a dual-line hybrid sensor that combines the elements of ported coax and CWD technology, and a rapid-deployment portable sensor for temporary or mobile applications. A description of the technology, the sensors, and their characteristics is provided

  13. Sensing performances of ZnO nanostructures grown under different oxygen pressures to hydrogen

    Chu, Jin; Peng, Xiaoyan; Wang, Zhenbo; Feng, Peter

    2012-01-01

    Graphical abstract: Display Omitted Highlights: ► Surface morphology depends on the oxygen pressure. ► Structural degradation was observed for the ZnO samples when oxygen pressure was overhigh. ► The sensitivity of the ZnO-based sensors increase with grown oxygen pressure. -- Abstract: For extensive use in an industrialized process of individual ZnO nanostructures applied in gas sensors, a simple, inexpensive, and safe synthesis process is required. Here, nanostructured ZnO films were grown by a pulsed laser deposition technique under different oxygen pressures. Scanning electron microscopy images show nanopores, nanotips, and nanoparticles are obtained and energy dispersive X-ray spectroscopy data indicate oxygen concentration of the synthesized samples increases monotonously with oxygen pressure. The sensor based on ZnO with high oxygen concentration has high sensitivity, rapid response (9 s) and recovery (80 s) behavior to 500 ppm hydrogen below 150 °C. Experimental data indicate that high oxygen concentration effectively improves the sensing properties of nanostructured ZnO.

  14. Smart Optoelectronic Sensors and Intelligent Sensor Systems

    Sergey Y. YURISH

    2012-03-01

    Full Text Available Light-to-frequency converters are widely used in various optoelectronic sensor systems. However, a further frequency-to-digital conversion is a bottleneck in such systems due to a broad frequency range of light-to-frequency converters’ outputs. This paper describes an effective OEM design approach, which can be used for smart and intelligent sensor systems design. The design is based on novel, multifunctional integrated circuit of Universal Sensors & Transducers Interface especially designed for such sensor applications. Experimental results have confirmed an efficiency of this approach and high metrological performances.

  15. Seasonal Oxygen Dynamics in a Thermokarst Bog in Interior Alaska: Implications for Rates of Methane Oxidation

    Neumann, R. B.; Moorberg, C.; Wong, A.; Waldrop, M. P.; Turetsky, M. R.

    2015-12-01

    Methane is a potent greenhouse gas, and wetlands represent the largest natural source of methane to the atmosphere. However, much of the methane generated in anoxic wetlands never gets emitted to the atmosphere; up to >90% of generated methane can get oxidized to carbon dioxide. Thus, oxidation is an important methane sink and changes in the rate of methane oxidation can affect wetland methane emissions. Most methane is aerobically oxidized at oxic-anoxic interfaces where rates of oxidation strongly depend on methane and oxygen concentrations. In wetlands, oxygen is often the limiting substrate. To improve understanding of belowground oxygen dynamics and its impact on methane oxidation, we deployed two planar optical oxygen sensors in a thermokarst bog in interior Alaska. Previous work at this site indicated that, similar to other sites, rates of methane oxidation decrease over the growing season. We used the sensors to track spatial and temporal patterns of oxygen concentrations over the growing season. We coupled these in-situ oxygen measurements with periodic oxygen injection experiments performed against the sensor to quantify belowground rates of oxygen consumption. We found that over the season, the thickness of the oxygenated water layer at the peatland surface decreased. Previous research has indicated that in sphagnum-dominated peatlands, like the one studied here, rates of methane oxidation are highest at or slightly below the water table. It is in these saturated but oxygenated locations that both methane and oxygen are available. Thus, a seasonal reduction in the thickness of the oxygenated water layer could restrict methane oxidation. The decrease in thickness of the oxygenated layer coincided with an increase in the rate of oxygen consumption during our oxygen injection experiments. The increase in oxygen consumption was not explained by temperature; we infer it was due to an increase in substrate availability for oxygen consuming reactions and

  16. Lightweight Fiber Optic Gas Sensor for Monitoring Regenerative Food Production

    Schmidlin, Edward; Goswami, Kisholoy

    1995-01-01

    In this final report, Physical Optics Corporation (POC) describes its development of sensors for oxygen, carbon dioxide, and relative humidity. POC has constructed a phase fluorometer that can detect oxygen over the full concentration range from 0 percent to 100 percent. Phase-based measurements offer distinct advantages, such as immunity to source fluctuation, photobleaching, and leaching. All optics, optoelectronics, power supply, and the printed circuit board are included in a single box; the only external connections to the fluorometer are the optical fiber sensor and a power cord. The indicator-based carbon dioxide sensor is also suitable for short-term and discrete measurements over the concentration range from 0 percent to 100 percent. The optical fiber-based humidity sensor contains a porous core for direct interaction of the light beam with water vapor within fiber pores; the detection range for the humidity sensor is 10 percent to 100 percent, and response time is under five minutes. POC is currently pursuing the commercialization of these oxygen and carbon dioxide sensors for environmental applications.

  17. Optic nerve oxygen tension

    Kiilgaard, Jens Folke; Pedersen, D B; Eysteinsson, T

    2004-01-01

    The authors have previously reported that carbonic anhydrase inhibitors such as acetazolamide and dorzolamide raise optic nerve oxygen tension (ONPO(2)) in pigs. The purpose of the present study was to investigate whether timolol, which belongs to another group of glaucoma drugs called beta...

  18. Home Oxygen Therapy

    ... cold it can hurt your skin. Keep a fire extinguisher close by, and let your fire department know that you have oxygen in your ... any symptoms of illness. Medicare, Medicaid, and Commercial Insurance Certain insurance policies may pay for all your ...

  19. Central oxygen pipeline failure

    surgical intensive care unit (ICU), with two patients on full ventilation and ... uncertainty around the cause of the failure and the restoration, .... soon as its level also falls below three tons. Should ... (properly checked and closed prior to each anaesthetic). ... in use at the time of the central oxygen pipeline failure at Tygerberg.

  20. Extracorporeal membrane oxygenation (ECMO)

    Extracorporeal membrane oxygenation (ECMO) is not a novel therapy in the true sense of the ... Intention-to-treat analysis showed benefit for ECMO, with a relative risk ... no doubt that VV-ECMO is an advance in medical technology, and that.

  1. Towards Sensor Database Systems

    Bonnet, Philippe; Gehrke, Johannes; Seshadri, Praveen

    2001-01-01

    . These systems lack flexibility because data is extracted in a predefined way; also, they do not scale to a large number of devices because large volumes of raw data are transferred regardless of the queries that are submitted. In our new concept of sensor database system, queries dictate which data is extracted...... from the sensors. In this paper, we define the concept of sensor databases mixing stored data represented as relations and sensor data represented as time series. Each long-running query formulated over a sensor database defines a persistent view, which is maintained during a given time interval. We...... also describe the design and implementation of the COUGAR sensor database system....

  2. Oxygen Extraction from Minerals

    Muscatello, Tony

    2017-01-01

    Oxygen, whether used as part of rocket bipropellant or for astronaut life support, is a key consumable for space exploration and commercialization. In Situ Resource Utilization (ISRU) has been proposed many times as a method for making space exploration more cost effective and sustainable. On planetary and asteroid surfaces the presence of minerals in the regolith that contain oxygen is very common, making them a potential oxygen resource. The majority of research and development for oxygen extraction from minerals has been for lunar regolith although this work would generally be applicable to regolith at other locations in space. This presentation will briefly survey the major methods investigated for oxygen extraction from regolith with a focus on the current status of those methods and possible future development pathways. The major oxygen production methods are (1) extraction from lunar ilmenite (FeTiO3) with either hydrogen or carbon monoxide, (2) carbothermal reduction of iron oxides and silicates with methane, and (3) molten regolith electrolysis (MRE) of silicates. Methods (1) and (2) have also been investigated in a two-step process using CO reduction and carbon deposition followed by carbothermal reduction. All three processes have byproducts that could also be used as resources. Hydrogen or carbon monoxide reduction produce iron metal in small amounts that could potentially be used as construction material. Carbothermal reduction also makes iron metal along with silicon metal and a glass with possible applications. MRE produces iron, silicon, aluminum, titanium, and glass, with higher silicon yields than carbothermal reduction. On Mars and possibly on some moons and asteroids, water is present in the form of mineral hydrates, hydroxyl (-OH) groups on minerals, andor water adsorbed on mineral surfaces. Heating of the minerals can liberate the water which can be electrolyzed to provide a source of oxygen as well. The chemistry of these processes, some key

  3. Ocean Ridges and Oxygen

    Langmuir, C. H.

    2014-12-01

    The history of oxygen and the fluxes and feedbacks that lead to its evolution through time remain poorly constrained. It is not clear whether oxygen has had discrete steady state levels at different times in Earth's history, or whether oxygen evolution is more progressive, with trigger points that lead to discrete changes in markers such as mass independent sulfur isotopes. Whatever this history may have been, ocean ridges play an important and poorly recognized part in the overall mass balance of oxidants and reductants that contribute to electron mass balance and the oxygen budget. One example is the current steady state O2 in the atmosphere. The carbon isotope data suggest that the fraction of carbon has increased in the Phanerozoic, and CO2 outgassing followed by organic matter burial should continually supply more O2 to the surface reservoirs. Why is O2 not then increasing? A traditional answer to this question would relate to variations in the fraction of burial of organic matter, but this fraction appears to have been relatively high throughout the Phanerozoic. Furthermore, subduction of carbon in the 1/5 organic/carbonate proportions would contribute further to an increasingly oxidized surface. What is needed is a flux of oxidized material out of the system. One solution would be a modern oxidized flux to the mantle. The current outgassing flux of CO2 is ~3.4*1012 moles per year. If 20% of that becomes stored organic carbon, that is a flux of .68*1012 moles per year of reduced carbon. The current flux of oxidized iron in subducting ocean crust is ~2*1012 moles per year of O2 equivalents, based on the Fe3+/Fe2+ ratios in old ocean crust compared to fresh basalts at the ridge axis. This flux more than accounts for the incremental oxidizing power produced by modern life. It also suggests a possible feedback through oxygenation of the ocean. A reduced deep ocean would inhibit oxidation of ocean crust, in which case there would be no subduction flux of oxidized

  4. Microbial sensor for drug susceptibility testing of Mycobacterium tuberculosis.

    Zhang, Z-T; Wang, D-B; Li, C-Y; Deng, J-Y; Zhang, J-B; Bi, L-J; Zhang, X-E

    2018-01-01

    Drug susceptibility testing (DST) of clinical isolates of Mycobacterium tuberculosis is critical in treating tuberculosis. We demonstrate the possibility of using a microbial sensor to perform DST of M. tuberculosis and shorten the time required for DST. The sensor is made of an oxygen electrode with M. tuberculosis cells attached to its surface. This sensor monitors the residual oxygen consumption of M. tuberculosis cells after treatment with anti-TB drugs with glycerine as a carbon source. In principle, after drug pretreatment for 4-5 days, the response differences between the sensors made of drug-sensitive isolates are distinguishable from the sensors made of drug-resistant isolates. The susceptibility of the M. tuberculosis H37Ra strain, its mutants and 35 clinical isolates to six common anti-TB drugs: rifampicin, isoniazid, streptomycin, ethambutol, levofloxacin and para-aminosalicylic acid were tested using the proposed method. The results agreed well with the gold standard method (LJ) and were determined in significantly less time. The whole procedure takes approximately 11 days and therefore has the potential to inform clinical decisions. To our knowledge, this is the first study that demonstrates the possible application of a dissolved oxygen electrode-based microbial sensor in M. tuberculosis drug resistance testing. This study used the microbial sensor to perform DST of M. tuberculosis and shorten the time required for DST. The overall detection result of the microbial sensor agreed well with that of the conventional LJ proportion method and takes less time than the existing phenotypic methods. In future studies, we will build an O 2 electrode array microbial sensor reactor to enable a high-throughput drug resistance analysis. © 2017 The Authors. Journal of Applied Microbiology published by John Wiley & Sons Ltd on behalf of The Society for Applied Microbiology.

  5. Oxygen diffusion in monazite

    Cherniak, D. J.; Zhang, X. Y.; Nakamura, M.; Watson, E. B.

    2004-09-01

    We report measurements of oxygen diffusion in natural monazites under both dry, 1-atm conditions and hydrothermal conditions. For dry experiments, 18O-enriched CePO4 powder and monazite crystals were sealed in Ag-Pd capsules with a solid buffer (to buffer at NNO) and annealed in 1-atm furnaces. Hydrothermal runs were conducted in cold-seal pressure vessels, where monazite grains were encapsulated with 18O-enriched water. Following the diffusion anneals, oxygen concentration profiles were measured with Nuclear Reaction Analysis (NRA) using the reaction 18O(p,α)15N. Over the temperature range 850-1100 °C, the Arrhenius relation determined for dry diffusion experiments on monazite is given by: Under wet conditions at 100 MPa water pressure, over the temperature range 700-880 °C, oxygen diffusion can be described by the Arrhenius relationship: Oxygen diffusion under hydrothermal conditions has a significantly lower activation energy for diffusion than under dry conditions, as has been found the case for many other minerals, both silicate and nonsilicate. Given these differences in activation energies, the differences between dry and wet diffusion rates increase with lower temperatures; for example, at 600 °C, dry diffusion will be more than 4 orders of magnitude slower than diffusion under hydrothermal conditions. These disparate diffusivities will result in pronounced differences in the degree of retentivity of oxygen isotope signatures. For instance, under dry conditions (presumably rare in the crust) and high lower-crustal temperatures (∼800 °C), monazite cores of 70-μm radii will preserve O isotope ratios for about 500,000 years; by comparison, they would be retained at this temperature under wet conditions for about 15,000 years.

  6. Fundamental data: Solubility of nickel and oxygen and diffusivity of iron and oxygen in molten LBE

    Abella, J.; Verdaguer, A.; Colominas, S.; Ginestar, K.; Martinelli, L.

    2011-01-01

    Experiments for determining nickel solubility limit and iron diffusion coefficient are presented and their results are discussed. Nickel solubility limit is determined by two methods: ex situ by solid sampling followed by ICP-AES analysis and in situ by Laser Induced Breakdown Spectroscopy and their results are compared. The iron diffusion coefficient is obtained using the technique of rotating specimen dissolution. Also a method to determine the oxygen solubility and diffusivity in LBE is developed and results at 460, 500 and 540 deg. C are presented. It is based on the following electrochemical cell: O 2 (reference mixture), Pt //YSZ//O 2 (LBE) which can work as an oxygen sensor or as a coulometric pump.

  7. Flexible magnetoimpedance sensor

    Li, Bodong; Kavaldzhiev, Mincho; Kosel, Jü rgen

    2015-01-01

    Flexible magnetoimpedance (MI) sensors fabricated using a NiFe/Cu/NiFe tri-layer on Kapton substrate have been studied. A customized flexible microstrip transmission line was employed to investigate the MI sensors's magnetic field and frequency

  8. Air Sensor Toolbox

    Air Sensor Toolbox provides information to citizen scientists, researchers and developers interested in learning more about new lower-cost compact air sensor technologies and tools for measuring air quality.

  9. Invisible magnetic sensors

    Mach-Batlle, Rosa; Navau, Carles; Sanchez, Alvaro

    2018-04-01

    Sensing magnetic fields is essential in many applications in biomedicine, transportation, or smart cities. The distortion magnetic sensors create in response to the field they are detecting may hinder their use, for example, in applications requiring dense packaging of sensors or accurately shaped field distributions. For sensing electromagnetic waves, cloaking shells that reduce the scattering of sensors have been introduced. However, the problem of making a magnetic sensor undetectable remains unsolved. Here, we present a general strategy on how to make a sensor magnetically invisible while keeping its ability to sense. The sensor is rendered undetectable by surrounding it with a spherical shell having a tailored magnetic permeability. Our method can be applied to arbitrary shaped magnetic sensors in arbitrary magnetic fields. The invisibility can be made exact when the sensor is spherical and the probed field is uniform. A metasurface composed of superconducting pieces is presented as a practical realization of the ideal invisibility shell.

  10. Embedded sensor systems

    Agrawal, Dharma Prakash

    2017-01-01

    This inspiring textbook provides an introduction to wireless technologies for sensors, explores potential use of sensors for numerous applications, and utilizes probability theory and mathematical methods as a means of embedding sensors in system design. It discusses the need for synchronization and underlying limitations, inter-relation between given coverage and connectivity to number of sensors needed, and the use of geometrical distance to determine location of the base station for data collection and explore use of anchor nodes for relative position determination of sensors. The book explores energy conservation, communication using TCP, the need for clustering and data aggregation, and residual energy determination and energy harvesting. It covers key topics of sensor communication like mobile base stations and relay nodes, delay-tolerant sensor networks, and remote sensing and possible applications. The book defines routing methods and do performance evaluation for random and regular sensor topology an...

  11. Sensor Substrate Development

    National Aeronautics and Space Administration — Novel substrates, such as aerogels and porous, low density ceramics may increase the sensitivities of chemical reaction-based sensors for toxic vapors. These sensors...

  12. Digital Sensor Technology

    Ted Quinn; Jerry Mauck; Richard Bockhorst; Ken Thomas

    2013-07-01

    The nuclear industry has been slow to incorporate digital sensor technology into nuclear plant designs due to concerns with digital qualification issues. However, the benefits of digital sensor technology for nuclear plant instrumentation are substantial in terms of accuracy, reliability, availability, and maintainability. This report demonstrates these benefits in direct comparisons of digital and analog sensor applications. It also addresses the qualification issues that must be addressed in the application of digital sensor technology.

  13. Miniaturized Planar Room Temperature Ionic Liquid Electrochemical Gas Sensor for Rapid Multiple Gas Pollutants Monitoring.

    Wan, Hao; Yin, Heyu; Lin, Lu; Zeng, Xiangqun; Mason, Andrew J

    2018-02-01

    The growing impact of airborne pollutants and explosive gases on human health and occupational safety has escalated the demand of sensors to monitor hazardous gases. This paper presents a new miniaturized planar electrochemical gas sensor for rapid measurement of multiple gaseous hazards. The gas sensor features a porous polytetrafluoroethylene substrate that enables fast gas diffusion and room temperature ionic liquid as the electrolyte. Metal sputtering was utilized for platinum electrodes fabrication to enhance adhesion between the electrodes and the substrate. Together with carefully selected electrochemical methods, the miniaturized gas sensor is capable of measuring multiple gases including oxygen, methane, ozone and sulfur dioxide that are important to human health and safety. Compared to its manually-assembled Clark-cell predecessor, this sensor provides better sensitivity, linearity and repeatability, as validated for oxygen monitoring. With solid performance, fast response and miniaturized size, this sensor is promising for deployment in wearable devices for real-time point-of-exposure gas pollutant monitoring.

  14. Single Walled Carbon Nanotube Based Air Pocket Encapsulated Ultraviolet Sensor.

    Kim, Sun Jin; Han, Jin-Woo; Kim, Beomseok; Meyyappan, M

    2017-11-22

    Carbon nanotube (CNT) is a promising candidate as a sensor material for the sensitive detection of gases/vapors, biomarkers, and even some radiation, as all these external variables affect the resistance and other properties of nanotubes, which forms the basis for sensing. Ultraviolet (UV) radiation does not impact the nanotube properties given the substantial mismatch of bandgaps and therefore, CNTs have never been considered for UV sensing, unlike the popular ZnO and other oxide nanwires. It is well-known that UV assists the adsorption/desorption characteristics of oxygen on carbon nanotubes, which changes the nanotube resistance. Here, we demonstrate a novel sensor structure encapsulated with an air pocket, where the confined air is responsible for the UV sensing mechanism and assures sensor stability and repeatability over time. In addition to the protection from any contamination, the air pocket encapsulated sensor offers negligible baseline drift and fast recovery compared to previously reported sensors. The air pocket isolated from the outside environment can act as a stationary oxygen reservoir, resulting in consistent sensor characteristics. Furthermore, this sensor can be used even in liquid environments.

  15. Development of a hydrogel-based carbon dioxide sensor : a tool for diagnosing gastrointestinal ischemia

    Herber, S.

    2005-01-01

    In this thesis the development of a new type of CO2 sensor is described. The main application of the sensor is measuring the partial pressure of CO2 in the stomach to diagnose gastrointestinal ischemia, which occurs when blood flow is insufficient to deliver oxygen to the stomach and intestines.

  16. Focus on image sensors

    Jos Gunsing; Daniël Telgen; Johan van Althuis; Jaap van de Loosdrecht; Mark Stappers; Peter Klijn

    2013-01-01

    Robots need sensors to operate properly. Using a single image sensor, various aspects of a robot operating in its environment can be measured or monitored. Over the past few years, image sensors have improved a lot: frame rate and resolution have increased, while prices have fallen. As a result,

  17. Multi-Sensor Architectures

    Hussain, Dil Muhammad Akbar; Ahmed, Zaki; Khan, M. Z.

    2012-01-01

    The use of multiple sensors typically requires the fusion of data from different type of sensors. The combined use of such a data has the potential to give an efficient, high quality and reliable estimation. Input data from different sensors allows the introduction of target attributes (target ty...

  18. Thermal flow micro sensors

    Elwenspoek, Michael Curt

    1999-01-01

    A review is given on sensors fabricated by silicon micromachining technology using the thermal domain for the measurement of fluid flow. Attention is paid especially to performance and geometry of the sensors. Three basic types of thermal flow sensors are discussed: anemometers, calorimetric flow

  19. Sensors for Entertainment

    Fabrizio Lamberti

    2016-07-01

    Full Text Available Sensors are becoming ubiquitous in all areas of science, technology, and society. In this Special Issue on “Sensors for Entertainment”, developments in progress and the current state of application scenarios for sensors in the field of entertainment is explored.

  20. Electric field sensor studies

    Griffith, R.D.; Parks, S.

    1977-01-01

    Above-ground intrusion sensors are reviewed briefly. Buried wire sensors are next considered; feasibility studies were conducted. A triangular system of an overhead transmitter wire exciting two buried sensor wires was developed and tested. It failed sometimes to detect a man making a broad jump. A differential receiver was developed to solve this problem

  1. Electrochemical cell with integrated hydrocarbon gas sensor for automobile exhaust gas; Elektrochemische Zelle mit integriertem Kohlenwasserstoff-Gassensor fuer das Automobilabgas

    Biskupski, D.; Moos, R. [Univ. Bayreuth (Germany). Bayreuth Engine Research Center, Lehrstuhl fuer Funktionsmaterialien; Wiesner, K.; Fleischer, M. [Siemens AG, Corporate Technology, CT PS 6, Muenchen (Germany)

    2007-07-01

    In the future sensors will be necessary to control the compliance with hydrocarbon limiting values, allowing a direct detection of the hydrocarbons. Appropriate sensor-active functional materials are metal oxides, which have a hydrocarbon sensitivity but are also dependent on the oxygen partial pressure. It is proposed that the gas-sensing layer should be integrated into an electrochemical cell. The authors show that the integration of a resistive oxygen sensor into a pump cell allows a defined oxygen concentration level at the sensor layer in any exhaust gas.

  2. Origin of photosynthetic oxygen

    Gerster, Richard; Dupuy, Jacques; Guerin de Montgareuil, Pierre

    From the comparison of isotopic exchange kinetics between C 18 O 2 and the water of algae suspensions or aerial leaves subjected to alternating darkness and light, it becomes possible to calculate the isotopic abundance of the CO 2 involved in the photochemical process; this value has been compared to those of the intracellular water and of the evolved O 2 . Kinetics of the appearance of 18 O in the oxygen produced by algae suspended in enriched water are also presented [fr

  3. Oxygen injection facility

    Ota, Masamoto; Hirose, Yuki

    1998-01-01

    A compressor introduces air as a starting material and sends it to a dust removing device, a dehumidifying device and an adsorption/separation system disposed downstream. The facility of the present invention is disposed in the vicinity of an injection point and installed in a turbine building of a BWR type reactor having a pipeline of a feedwater system to be injected. The adsorbing/separation system comprises an adsorbing vessel and an automatic valve, and the adsorbing vessel is filled with an adsorbent for selectively adsorbing nitrogen. Zeolite is used as the adsorbent. Nitrogen in the air passing through the adsorbing vessel is adsorbed and removed under a pressurized condition, and a highly concentrated oxygen gas is formed. The direction of the steam of the adsorbed nitrogen is changed by an opening/closing switching operation of an automatic valve and released to the atmosphere (the pressure is released). Generated oxygen gas is stored under pressure in a tank, and injected to the pipeline of the feedwater system by an oxygen injection conduit by way of a flow rate control valve. In the adsorbing vessel, steps of adsorption, separation and storage under pressure are repeated successively. (I.N.)

  4. ITM oxygen for gasification

    Armstrong, P.A.; Foster, E.P. [Air Products and Chemicals Inc., Toronto, ON (Canada); Gunardson, H.H. [Air Products Canada Ltd., Mississauga, ON (Canada)

    2005-11-01

    This paper described a newly developed air separation technology called Ionic Transport Membrane (ITM), which reduces the overall cost of the gasification process. The technology is well suited for advanced energy conversion processes such as integrated gasification combined cycle (IGCC) that require oxygen and use heavy carbonaceous feedstocks such as residual oils, bitumens, coke and coal. It is also well suited for traditional industrial applications for oxygen and distributed power. Air Products Canada Limited developed the ceramic membrane air separation technology that can reduce the cost of pure oxygen by more than 30 per cent. The separation technology achieves a capital cost reduction of 30 per cent and an energy reduction of 35 per cent over conventional cryogenic air separation. ITM is an electrochemical process that integrates well with the gasification process and an IGCC option for producing electricity from the waste heat generated from gasification. This paper described the integration of ITM technology with both the gasification and IGCC processes and showed the attractive economics of ITM. 6 refs., 2 tabs., 6 figs.

  5. Advanced Materials Development of Ionic Ceramics Using Ions Beam and its Suitable Applications as Stress Environment Sensor

    Lee, K. H.; Cho, D. H.; Won, J. O.; Cho, J. H.; Kim, J. Y.

    2008-04-01

    The perovskite oxides La 2 CuO 4 was prepared by auto-ignition method with citric acid as reductant and nitrate as oxidant at low temperatures. Single crystals of phase lanthanum copper oxide were implanted with 70-120 KeV argon and nitrogen ions at room temperature. The prepared materials have investigated the energy transition distribution and ion distribution for N 2 and Ar ion-implantation depth. Also, this ionic ceramic of ion implanted with N + and N 2 + energy 70 keV, dose 5 x 10 16 ions/cm 2 , and beam current density 8.91μm/cm 2 were studied on physio-chemical and characteristic. We have studied on the effect of ion implantation for ionic ceramics materials surface modification for the first year. The ion beam treated ionic ceramics were investigated into its chemical structure and its characteristics as observed by XRD, SEM-EDS, BET and DTA. The oxygen gas sensors based on lanthanum copper oxide were fabricated by screen-printing method an YSZ substrate using the powder prepared by the ion implanted ionic state ceramics. The sensor's response was evaluated by periodic variation of oxygen partial pressure. Recently, the oxygen gas sensors using concentration cells consisting of oxygen-ion-conductor have been currently used as the oxygen gas sensors to measure oxygen concentration of exhaust gas. And, Resistive response behavior with varying oxygen gas concentration on lanthanum copper oxide have been studied. Oxygen sensor was measured in the temperature range of 400 .deg. C ∼700 .deg. C and different concentrations of oxygen. The results show that the resistance of oxygen sensor using YSZ-La 2 CuO 4 decreases with an increase of temperature at given oxygen concentration, and it is good linearity. Also its sensor has faster response property at more than 500 .deg. C.

  6. An approach to fabricating chemical sensors based on ZnO nanorod arrays

    Park, Jae Young; Song, Dong Eon; Kim, Sang Sub

    2008-01-01

    Vertically and laterally aligned ZnO nanorod arrays were synthesized on Pt-coated Si substrates by catalyst-free metal organic chemical vapor deposition. An approach to fabricating chemical sensors based on the nanorod arrays using a coating-and-etching process with a photo-resist is reported. Tests of the devices as oxygen gas sensors have been performed. Our results demonstrate that the approach holds promise for the realization of sensitive and reliable nanorod array chemical sensors

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

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

    1990-01-01

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

  8. Optical hydrogen sensors based on metal-hydrides

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

    2012-06-01

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

  9. Dissolved oxygen sensing using organometallic dyes deposited within a microfluidic environment

    Chen, Q. L.; Ho, H. P.; Jin, L.; Chu, B. W.-K.; Li, M. J.; Yam, V. W.-W.

    2008-02-01

    This work primarily aims to integrate dissolved oxygen sensing capability with a microfluidic platform containing arrays of micro bio-reactors or bio-activity indicators. The measurement of oxygen concentration is of significance for a variety of bio-related applications such as cell culture and gene expression. Optical oxygen sensors based on luminescence quenching are gaining much interest in light of their low power consumption, quick response and high analyte sensitivity in comparison to similar oxygen sensing devices. In our microfluidic oxygen sensor device, a thin layer of oxygen-sensitive luminescent organometallic dye is covalently bonded to a glass slide. Micro flow channels are formed on the glass slide using patterned PDMS (Polydimethylsiloxane). Dissolved oxygen sensing is then performed by directing an optical excitation probe beam to the area of interest within the microfluidic channel. The covalent bonding approach for sensor layer formation offers many distinct advantages over the physical entrapment method including minimizing dye leaching, ensuring good stability and fabrication simplicity. Experimental results confirm the feasibility of the device.

  10. Virtual Sensor Test Instrumentation

    Wang, Roy

    2011-01-01

    Virtual Sensor Test Instrumentation is based on the concept of smart sensor technology for testing with intelligence needed to perform sell-diagnosis of health, and to participate in a hierarchy of health determination at sensor, process, and system levels. A virtual sensor test instrumentation consists of five elements: (1) a common sensor interface, (2) microprocessor, (3) wireless interface, (4) signal conditioning and ADC/DAC (analog-to-digital conversion/ digital-to-analog conversion), and (5) onboard EEPROM (electrically erasable programmable read-only memory) for metadata storage and executable software to create powerful, scalable, reconfigurable, and reliable embedded and distributed test instruments. In order to maximize the efficient data conversion through the smart sensor node, plug-and-play functionality is required to interface with traditional sensors to enhance their identity and capabilities for data processing and communications. Virtual sensor test instrumentation can be accessible wirelessly via a Network Capable Application Processor (NCAP) or a Smart Transducer Interlace Module (STIM) that may be managed under real-time rule engines for mission-critical applications. The transducer senses the physical quantity being measured and converts it into an electrical signal. The signal is fed to an A/D converter, and is ready for use by the processor to execute functional transformation based on the sensor characteristics stored in a Transducer Electronic Data Sheet (TEDS). Virtual sensor test instrumentation is built upon an open-system architecture with standardized protocol modules/stacks to interface with industry standards and commonly used software. One major benefit for deploying the virtual sensor test instrumentation is the ability, through a plug-and-play common interface, to convert raw sensor data in either analog or digital form, to an IEEE 1451 standard-based smart sensor, which has instructions to program sensors for a wide variety of

  11. Piezoelectric Zinc Oxide Based MEMS Acoustic Sensor

    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.

  12. Oxygen diffusion in zircon

    Watson, E. B.; Cherniak, D. J.

    1997-05-01

    Oxygen diffusion in natural, non-metamict zircon was characterized under both dry and water-present conditions at temperatures ranging from 765°C to 1500°C. Dry experiments were performed at atmospheric pressure by encapsulating polished zircon samples with a fine powder of 18O-enriched quartz and annealing the sealed capsules in air. Hydrothermal runs were conducted in cold-seal pressure vessels (7-70 MPa) or a piston cylinder apparatus (400-1000 MPa) on zircon samples encapsulated with both 18O-enriched quartz and 18O water. Diffusive-uptake profiles of 18O were measured in all samples with a particle accelerator, using the 18O(p, α) 15N reaction. For dry experimental conditions at 1100-1500°C, the resulting oxygen diffusivities (24 in all) are well described by: D dry (m 2/s) = 1.33 × 10 -4exp(-53920/T) There is no suggestion of diffusive anisotropy. Under wet conditions at 925°C, oxygen diffusion shows little or no dependence upon P H 2O in the range 7-1000 MPa, and is insensitive to total pressure as well. The results of 27 wet experiments at 767-1160°C and 7-1000 MPa can be described a single Arrhenius relationship: D wet (m 2/s) = 5.5 × 10 -12exp(-25280/T) The insensitivity of oxygen diffusion to P H 2O means that applications to geologic problems can be pursued knowing only whether the system of interest was 'wet' (i.e., P H 2O > 7MPa ) or 'dry'. Under dry conditions (presumably rare in the crust), zircons are extremely retentive of their oxygen isotopic signatures, to the extent that δ 18O would be perturbed at the center of a 200 μm zircon only during an extraordinarily hot and protracted event (e.g., 65 Ma at 900°C). Under wet conditions, δ 18O may or may not be retained in the central regions of individual crystals, cores or overgrowth rims, depending upon the specific thermal history of the system.

  13. Hydrostatic force sensor

    Evans, M.S.; Stoughton, R.S.; Kazerooni, H.

    1994-08-01

    This paper presents a theoretical and experimental investigation of a new kind of force sensor which detects forces by measuring an induced pressure change in a material of large Poisson's ratio. In this investigation we develop mathematical expressions for the sensor's sensitivity and bandwidth, and show that its sensitivity can be much larger and its bandwidth is usually smaller than those of existing strain-gage-type sensors. This force sensor is well-suited for measuring large but slowly varying forces. It can be installed in a space smaller than that required by existing sensors

  14. Multifuctional integrated sensors (MFISES).

    Homeijer, Brian D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Roozeboom, Clifton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-10-01

    Many emerging IoT applications require sensing of multiple physical and environmental parameters for: completeness of information, measurement validation, unexpected demands, improved performance. For example, a typical outdoor weather station measures temperature, humidity, barometric pressure, light intensity, rainfall, wind speed and direction. Existing sensor technologies do not directly address the demand for cost, size, and power reduction in multi-paramater sensing applications. Industry sensor manufacturers have developed integrated sensor systems for inertial measurements that combine accelerometers, gyroscopes, and magnetometers, but do not address environmental sensing functionality. In existing research literature, a technology gap exists between the functionality of MEMS sensors and the real world applications of the sensors systems.

  15. Oxygen Transport Membranes

    S. Bandopadhyay

    2008-08-30

    The focus of this research was to develop new membrane materials by synthesizing different compounds and determining their defect structures, crystallographic structures and electrical properties. In addition to measuring electrical conductivity, oxygen vacancy concentration was also evaluated using thermogravimetry, Neutron diffraction and Moessbauer Spectroscopy. The reducing conditions (CO{sub 2}/CO/H{sub 2} gas mixtures with steam) as encountered in a reactor environment can be expected to have significant influence on the mechanical properties of the oxides membranes. Various La based materials with and without Ti were selected as candidate membrane materials for OTM. The maximum electrical conductivity of LSF in air as a function of temperature was achieved at < 600 C and depends on the concentration of Sr (acceptor dopant). Oxygen occupancy in LSF was estimated using Neutron diffractometry and Moessbauer Spectroscopy by measuring magnetic moment changes depending on the Fe{sup 3+} and Fe{sup 4+} ratio. After extensive studies of candidate materials, lanthanum ferrites (LSF and LSFT) were selected as the favored materials for the oxygen transport membrane (OTM). LSF is a very good material for an OTM because of its high electronic and oxygen ionic conductivity if long term stability and mechanical strength are improved. LSFT not only exhibits p-type behavior in the high oxygen activity regime, but also has n-type conduction in reducing atmospheres. Higher concentrations of oxygen vacancies in the low oxygen activity regime may improve the performance of LSFT as an OTM. The hole concentration is related to the difference in the acceptor and donor concentration by the relation p = [Sr'{sub La}]-[Ti{sm_bullet}{sub Fe}]. The chemical formulation predicts that the hole concentration is, p = 0.8-0.45 or 0.35. Experimental measurements indicated that p is about {approx} 0.35. The activation energy of conduction is 0.2 eV which implies that LSCF conducts via the

  16. Theory of oxygen isotope exchange

    den Otter, M.W.; Boukamp, Bernard A.; Bouwmeester, Henricus J.M.

    2001-01-01

    Transients for oxygen molecular mass numbers 32, 34 and 36 are derived which can be used for the interpretation of oxygen isotope exchange data based on measurement of concentrations of 16O2, 16O18O and 18O2 in the gas phase. Key parameters in the theory are the rate at which oxygen molecules are

  17. Mixed oxygen ion/electron-conducting ceramics for oxygen separation

    Stevenson, J.W.; Armstrong, T.R.; Armstrong, B.L. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-08-01

    Mixed oxygen ion and electron-conducting ceramics are unique materials that can passively separate high purity oxygen from air. Oxygen ions move through a fully dense ceramic in response to an oxygen concentration gradient, charge-compensated by an electron flux in the opposite direction. Compositions in the system La{sub 1{minus}x}M{sub x}Co{sub 1{minus}y{minus}z}Fe{sub y}N{sub z}O{sub 3{minus}{delta}}, perovskites where M=Sr, Ca, and Ba, and N=Mn, Ni, Cu, Ti, and Al, have been prepared and their electrical, oxygen permeation, oxygen vacancy equilibria, and catalytic properties evaluated. Tubular forms, disks, and asymmetric membrane structures, a thin dense layer on a porous support of the same composition, have been fabricated for testing purposes. In an oxygen partial gradient, the passive oxygen flux through fully dense structures was highly dependent on composition. An increase in oxygen permeation with increased temperature is attributed to both enhanced oxygen vacancy mobility and higher vacancy populations. Highly acceptor-doped compositions resulted in oxygen ion mobilities more than an order of magnitude higher than yttria-stabilized zirconia. The mixed conducting ceramics have been utilized in a membrane reactor configuration to upgrade methane to ethane and ethylene. Conditions were established to balance selectivity and throughput in a catalytic membrane reactor constructed from mixed conducting ceramics.

  18. Sensor mount assemblies and sensor assemblies

    Miller, David H [Redondo Beach, CA

    2012-04-10

    Sensor mount assemblies and sensor assemblies are provided. In an embodiment, by way of example only, a sensor mount assembly includes a busbar, a main body, a backing surface, and a first finger. The busbar has a first end and a second end. The main body is overmolded onto the busbar. The backing surface extends radially outwardly relative to the main body. The first finger extends axially from the backing surface, and the first finger has a first end, a second end, and a tooth. The first end of the first finger is disposed on the backing surface, and the tooth is formed on the second end of the first finger.

  19. The significance of feedback control for chemical sensors

    Bergveld, Piet

    1992-01-01

    The conventional way of applying chemical sensors is in an open-loop configuration. A parameter of the chemical domain, such as a gas or ion concentration, is converted into a parameter of the mechanical or electrical domain, often with non-linear transfer characteristics. The paramagnetic oxygen

  20. Operations and Maintenance Manual, Atmospheric Contaminant Sensor, Revision B.

    National Aeronautics and Space Administration, Washington, DC.

    The sensor is a mass spectrometer system which continuously monitors the atmospheric constituents of hydrogen, water vapor, nitrogen, oxygen, and carbon dioxide, and monitors the Freons on a demand sampling basis. The manual provides a system description, operational procedures, and maintenance and troubleshooting instructions. Circuit diagrams…

  1. Wireless Biological Electronic Sensors.

    Cui, Yue

    2017-10-09

    The development of wireless biological electronic sensors could open up significant advances for both fundamental studies and practical applications in a variety of areas, including medical diagnosis, environmental monitoring, and defense applications. One of the major challenges in the development of wireless bioelectronic sensors is the successful integration of biosensing units and wireless signal transducers. In recent years, there are a few types of wireless communication systems that have been integrated with biosensing systems to construct wireless bioelectronic sensors. To successfully construct wireless biological electronic sensors, there are several interesting questions: What types of biosensing transducers can be used in wireless bioelectronic sensors? What types of wireless systems can be integrated with biosensing transducers to construct wireless bioelectronic sensors? How are the electrical sensing signals generated and transmitted? This review will highlight the early attempts to address these questions in the development of wireless biological electronic sensors.

  2. MEMS optical sensor

    2013-01-01

    The present invention relates to an all-optical sensor utilizing effective index modulation of a waveguide and detection of a wavelength shift of reflected light and a force sensing system accommodating said optical sensor. One embodiment of the invention relates to a sensor system comprising...... at least one multimode light source, one or more optical sensors comprising a multimode sensor optical waveguide accommodating a distributed Bragg reflector, at least one transmitting optical waveguide for guiding light from said at least one light source to said one or more multimode sensor optical...... waveguides, a detector for measuring light reflected from said Bragg reflector in said one or more multimode sensor optical waveguides, and a data processor adapted for analyzing variations in the Bragg wavelength of at least one higher order mode of the reflected light....

  3. Digital Sensor Technology

    Thomas, Ken D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Quinn, Edward L. [Technology Resources, Dana Point, CA (United States); Mauck, Jerry L. [Technology Resources, Dana Point, CA (United States); Bockhorst, Richard M. [Technology Resources, Dana Point, CA (United States)

    2015-02-01

    The nuclear industry has been slow to incorporate digital sensor technology into nuclear plant designs due to concerns with digital qualification issues. However, the benefits of digital sensor technology for nuclear plant instrumentation are substantial in terms of accuracy and reliability. This paper, which refers to a final report issued in 2013, demonstrates these benefits in direct comparisons of digital and analog sensor applications. Improved accuracy results from the superior operating characteristics of digital sensors. These include improvements in sensor accuracy and drift and other related parameters which reduce total loop uncertainty and thereby increase safety and operating margins. An example instrument loop uncertainty calculation for a pressure sensor application is presented to illustrate these improvements. This is a side-by-side comparison of the instrument loop uncertainty for both an analog and a digital sensor in the same pressure measurement application. Similarly, improved sensor reliability is illustrated with a sample calculation for determining the probability of failure on demand, an industry standard reliability measure. This looks at equivalent analog and digital temperature sensors to draw the comparison. The results confirm substantial reliability improvement with the digital sensor, due in large part to ability to continuously monitor the health of a digital sensor such that problems can be immediately identified and corrected. This greatly reduces the likelihood of a latent failure condition of the sensor at the time of a design basis event. Notwithstanding the benefits of digital sensors, there are certain qualification issues that are inherent with digital technology and these are described in the report. One major qualification impediment for digital sensor implementation is software common cause failure (SCCF).

  4. Development of SERS active fibre sensors

    Polwart, Ewan

    2002-01-01

    Surface-enhanced Raman scattering (SERS) is sensitive and selective and when coupled with fibre-optics could potentially produce an effective chemical sensing system. This thesis concerns the development of a single-fibre-based sensor, with an integral SERS-active substrate. A number of different methods for the manufacture of SERS-active surfaces on glass substrates were investigated and compared. The immobilisation of metal nanoparticles on glass functionalised with (3-aminopropyl)trimethoxysilane emerged as a suitable approach for the production of sensors. Substrates prepared by this approach were characterised using UV-visible spectroscopy, electron microscopy and Raman mapping. It was found that exposure of substrates to laser radiation led to a decrease in the signal recorded from adsorbed analytes. This speed of the decrease was shown to depend on the analyte, and the exciting wavelength and power. SERS-active fibre sensors were produced by immobilisation of silver nanoparticles at the distal end of a (3-aminopropyl)trimethoxysilane-derivatised optical fibre. These sensors were used to obtain spectra with good signal to noise ratios from 4-(benzotriazol-5-ylazo)-3,5-dimethoxyphenylamine and crystal violet. Sensing of dyes in effluent was also investigated. The development of sensors for the measurement of pH, by treating the SERS-active fibre tip with pH sensitive dyes is also described. Spectral changes were observed with these sensors as a response to the pH. Partial least squares regression was used to produce linear calibration models for the pH range 5-11 from which it was possible to predict the pH with an accuracy of ∼0.2 pH units. Some of the limitations of these sensors were explored. The feasibility of using these sensors for measurement of oxygen and thiols, was investigated. The measurement of oxygen using methylene blue as a transducer was demonstrated. Two transduction methodologies--reactions with iron porphyrins and pyrrole-2,5-diones

  5. Zirconium oxide based ceramic solid electrolytes for oxygen detection

    Caproni, Erica

    2007-01-01

    Taking advantage of the high thermal shock resistance of zirconia-magnesia ceramics and the high oxide ion conductivity of zirconia-yttria ceramics, composites of these ceramics were prepared by mixing, pressing and sintering different relative concentrations of ZrO 2 : 8.6 mol% MgO and ZrO 2 : 3 mol% Y 2 O 3 solid electrolytes. Microstructural analysis of the composites was carried out by X-ray diffraction and scanning electron microscopy analyses. The thermal behavior was studied by dilatometric analysis. The electrical behavior was evaluated by the impedance spectroscopy technique. An experimental setup was designed for measurement the electrical signal generated as a function of the amount of oxygen at high temperatures. The main results show that these composites are partially stabilized (monoclinic, cubic and tetragonal) and the thermal behavior is similar to that of ZrO 2 : 8.6 mol% MgO materials used in disposable high temperature oxygen sensors. Moreover, the results of analysis of impedance spectroscopy show that the electrical conductivity of zirconia:magnesia is improved with zirconia-yttria addition and that the electrical signal depends on the amount of oxygen at 1000 deg C, showing that the ceramic composites can be used in oxygen sensors. (author)

  6. Toxin detection using a tyrosinase-coupled oxygen electrode.

    Smit, M H; Rechnitz, G A

    1993-02-15

    An enzyme-based "electrochemical canary" is described for the detection of cyanide. The sensing system imitates cyanide's site of toxicity in the mitochondria. The terminal sequence of electron transfer in aerobic respiration is mimicked by mediator coupling of tyrosinase catalysis to an electro-chemical system. An enzyme-coupled oxygen electrode is created which is sensitive to selective poisoning. Biocatalytic reduction of oxygen is promoted by electrochemically supplying tyrosinase with electrons. Thus, ferrocyanide is generated at a cathode and mediates the enzymatic reduction of oxygen to water. An enzyme-dependent reductive current can be monitored which is inhibited by cyanide in a concentration-dependent manner. Oxygen depletion in the reaction layer can be minimized by addressing enzyme activity using a potential pulsing routine. Enzyme activity is electrochemically initiated and terminated and the sensor becomes capable of continuous monitoring. Cyanide poisoning of the biological component is reversible, and it can be reused after rinsing. The resulting sensor detects cyanide based on its biological activity rather than its physical or chemical properties.

  7. TAMOAS: In Situ Gasometry in the Atmosphere with Solid Electrolyte Sensors on BEXUS-19

    Bronowski, A.; Clemens, R.; Jaster, T.; Kosel, F.; Matyash, I.; Westphal, A.

    2015-09-01

    A student experiment developed for testing gas sensors in the stratosphere is described. The setup consists of a measurement electronic running miniaturized in situ amperiometric gas sensors based on different solid state electrolytes dedicated for oxygen, ozone and atomic oxygen. The experiment took place at Esrange Space Center in October 2014. The setup was attached to the high-altitude balloon BEXUS-19 and reached an altitude of 27 km at night. The primary objective was to test the prototype sensors and to gain data during flight.

  8. Influence of Pd Layer on the Sensitivity of CHx/PS/Si as Structure for Oxygen Sensing

    N. Ghellai

    2008-04-01

    Full Text Available It has been demonstrated recently that the fabricated gas sensing device based on hydrocarbons (CHx/Porous silicon structure can be used for detecting a low concentration of a large variety of gases but does not respond to oxygen. In this work, an oxygen sensor based on Palladium/hydrocarbons (CHx/ Porous silicon/ Silicon structure has been studied in presence of oxygen gas. Current-voltage and capacitance-voltage characterizations show that Pd/CHx-PS/Si structure is very sensitive toward O2 gas. A fast response time of the sensor of about 3 s is measured.

  9. HEAT Sensor: Harsh Environment Adaptable Thermionic Sensor

    Limb, Scott J. [Palo Alto Research Center, Palo Alto, CA (United States)

    2016-05-31

    This document is the final report for the “HARSH ENVIRONMENT ADAPTABLE THERMIONIC SENSOR” project under NETL’s Crosscutting contract DE-FE0013062. This report addresses sensors that can be made with thermionic thin films along with the required high temperature hermetic packaging process. These sensors can be placed in harsh high temperature environments and potentially be wireless and self-powered.

  10. Wireless Integrated Microelectronic Vacuum Sensor System

    Krug, Eric; Philpot, Brian; Trott, Aaron; Lawrence, Shaun

    2013-01-01

    NASA Stennis Space Center's (SSC's) large rocket engine test facility requires the use of liquid propellants, including the use of cryogenic fluids like liquid hydrogen as fuel, and liquid oxygen as an oxidizer (gases which have been liquefied at very low temperatures). These fluids require special handling, storage, and transfer technology. The biggest problem associated with transferring cryogenic liquids is product loss due to heat transfer. Vacuum jacketed piping is specifically designed to maintain high thermal efficiency so that cryogenic liquids can be transferred with minimal heat transfer. A vacuum jacketed pipe is essentially two pipes in one. There is an inner carrier pipe, in which the cryogenic liquid is actually transferred, and an outer jacket pipe that supports and seals the vacuum insulation, forming the "vacuum jacket." The integrity of the vacuum jacketed transmission lines that transfer the cryogenic fluid from delivery barges to the test stand must be maintained prior to and during engine testing. To monitor the vacuum in these vacuum jacketed transmission lines, vacuum gauge readings are used. At SSC, vacuum gauge measurements are done on a manual rotation basis with two technicians, each using a handheld instrument. Manual collection of vacuum data is labor intensive and uses valuable personnel time. Additionally, there are times when personnel cannot collect the data in a timely fashion (i.e., when a leak is detected, measurements must be taken more often). Additionally, distribution of this data to all interested parties can be cumbersome. To simplify the vacuum-gauge data collection process, automate the data collection, and decrease the labor costs associated with acquiring these measurements, an automated system that monitors the existing gauges was developed by Invocon, Inc. For this project, Invocon developed a Wireless Integrated Microelectronic Vacuum Sensor System (WIMVSS) that provides the ability to gather vacuum

  11. Compliant Tactile Sensors

    Torres-Jara, Eduardo R.

    2011-01-01

    Tactile sensors are currently being designed to sense interactions with human hands or pen-like interfaces. They are generally embedded in screens, keyboards, mousepads, and pushbuttons. However, they are not well fitted to sense interactions with all kinds of objects. A novel sensor was originally designed to investigate robotics manipulation where not only the contact with an object needs to be detected, but also where the object needs to be held and manipulated. This tactile sensor has been designed with features that allow it to sense a large variety of objects in human environments. The sensor is capable of detecting forces coming from any direction. As a result, this sensor delivers a force vector with three components. In contrast to most of the tactile sensors that are flat, this one sticks out from the surface so that it is likely to come in contact with objects. The sensor conforms to the object with which it interacts. This augments the contact's surface, consequently reducing the stress applied to the object. This feature makes the sensor ideal for grabbing objects and other applications that require compliance with objects. The operational range of the sensor allows it to operate well with objects found in peoples' daily life. The fabrication of this sensor is simple and inexpensive because of its compact mechanical configuration and reduced electronics. These features are convenient for mass production of individual sensors as well as dense arrays. The biologically inspired tactile sensor is sensitive to both normal and lateral forces, providing better feedback to the host robot about the object to be grabbed. It has a high sensitivity, enabling its use in manipulation fingers, which typically have low mechanical impedance in order to be very compliant. The construction of the sensor is simple, using inexpensive technologies like silicon rubber molding and standard stock electronics.

  12. Sensor for metal detection

    Kodzius, Rimantas

    2014-06-26

    NOVELTY - The sensor has a microfluidic flow channel that is provided with an inlet port, an outlet port, and a detection chamber. The detection chamber is provided with a group of sensing electrodes (4) having a working electrode (8), a counter electrode (9), and a reference electrode (10). A flow sensor is configured to measure flow in the channel. A temperature sensor (6) is configured to measure temperature in the channel (3). An electrical connection is configured to connect the sensor to a sensing device. USE - Sensor for detecting metal such as toxic metal in sample such as clinical sample such as stool, saliva, sputum, bronchial lavage, urine, vaginal swab, nasal swab, biopsy, tissue, tears, breath, blood, serum, plasma, cerebrospinal fluid, peritoneal fluid, pleural fluid, pericardial fluid, joint fluid, and amniotic fluid, water sample, food sample, air sample, and soil sample (all claimed). ADVANTAGE - The sensor for use with the portable analytical instrument is configured for detection of metalsin samples. The sensor can provide the excellent solution for on-site metal detection, including heavy metal detection. The sensors can provide significant advantages in higher throughput, lower cost, at the same time being less labor intensive and less dependent on individual skills. The disposable design of the sensor, the enhanced reliability and repeatability of measurements can be obtained. The sensors can be widely applied in various industries. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a system for detecting metal in sample; and (2) a method for using sensor for detecting metal in sample. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the sensor prototype. Channel (3) Sensing electrodes (4) Temperature sensor (6) Working electrode (8) Counter electrode (9) Reference electrode (10)

  13. Enabling new sensor applications for (V)HTRS by laser hybrid brazing of oxide ceramics

    Heilmann, F.; Rixecker, G. [Robert Bosch GmbH, Stuttgart (Germany). Corporate Research and Development; Herrmann, M.; Lippmann, W.; Hurtado, A. [Univ. of Technology, Dresden (Germany). Chair of Hydrogen- and Nuclear Engineering

    2008-07-01

    The use of (very) high temperature reactors ((V)HTRs) requires a sensor technology suitable to withstand thermal loads both in normal operation mode and under incident conditions which may appear during service. Especially ceramic sensors are ideal to suit this purpose. A special sensor type that is based upon oxide ceramics is the high temperature oxygen sensor. Base material for this application is yttria-doped zirconia. At elevated temperatures (above 450 C) the activation energy of oxygen ions is sufficient to migrate in the ZrO{sub 2} lattice following an oxygen partial pressure gradient. This diffusion process is facilitated by the trivalent yttrium ions which give rise to a high concentration of oxygen vacancies. The macroscopical effect of the migration of the oxygen ions can be detected as a Nernst voltage or, alternatively, as an electrical current. Thus it is possible to compare the oxygen content of measured media with that of a known reference gas. To be able to produce such sensors both efficiently and in the desired quality, joining technologies adapted to ceramics are necessary. Laser-based technologies for brazing with glass or glass-ceramic solders are especially suitable, as they combine high precision with high throughput. They thus enable cost efficient production processes both for large and small lot sizes. (orig.)

  14. Microfabricated electrochemical sensors for combustion applications

    Vulcano Rossi, Vitor A.; Mullen, Max R.; Karker, Nicholas A.; Zhao, Zhouying; Kowarz, Marek W.; Dutta, Prabir K.; Carpenter, Michael A.

    2015-05-01

    A new design for the miniaturization of an existing oxygen sensor is proposed based on the application of silicon microfabrication technologies to a cm sized O2 sensor demonstrated by Argonne National Laboratory and The Ohio State University which seals a metal/metal oxide within the structure to provide an integrated oxygen reference. The structural and processing changes suggested will result in a novel MEMS-based device meeting the semiconductor industry standards for cost efficiency and mass production. The MEMS design requires thin film depositions to create a YSZ membrane, palladium oxide reference and platinum electrodes. Pt electrodes are studied under operational conditions ensuring film conductivity over prolonged usage. SEM imaging confirms void formation after extended tests, consistent with the literature. Furthermore, hydrophilic bonding of pairs of silicon die samples containing the YSZ membrane and palladium oxide is discussed in order to create hermetic sealed cavities for oxygen reference. The introduction of tensile Si3N4 films to the backside of the silicon die generates bowing of the chips, compromising bond quality. This effect is controlled through the application of pressure during the initial bonding stages. In addition, KOH etching of the bonded die samples is discussed, and a YSZ membrane that survives the etching step is characterized by Raman spectroscopy.

  15. Oxygen-Methane Thruster

    Pickens, Tim

    2012-01-01

    An oxygen-methane thruster was conceived with integrated igniter/injector capable of nominal operation on either gaseous or liquid propellants. The thruster was designed to develop 100 lbf (approximately 445 N) thrust at vacuum conditions and use oxygen and methane as propellants. This continued development included refining the design of the thruster to minimize part count and manufacturing difficulties/cost, refining the modeling tools and capabilities that support system design and analysis, demonstrating the performance of the igniter and full thruster assembly with both gaseous and liquid propellants, and acquiring data from this testing in order to verify the design and operational parameters of the thruster. Thruster testing was conducted with gaseous propellants used for the igniter and thruster. The thruster was demonstrated to work with all types of propellant conditions, and provided the desired performance. Both the thruster and igniter were tested, as well as gaseous propellants, and found to provide the desired performance using the various propellant conditions. The engine also served as an injector testbed for MSFC-designed refractory combustion chambers made of rhenium.

  16. OXYGEN TRANSPORT CERAMIC MEMBRANES

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2000-10-01

    This is the third quarterly report on oxygen Transport Ceramic Membranes. In the following, the report describes the progress made by our university partners in Tasks 1 through 6, experimental apparatus that was designed and built for various tasks of this project, thermodynamic calculations, where applicable and work planned for the future. (Task 1) Design, fabricate and evaluate ceramic to metal seals based on graded ceramic powder/metal braze joints. (Task 2) Evaluate the effect of defect configuration on ceramic membrane conductivity and long term chemical and structural stability. (Task 3) Determine materials mechanical properties under conditions of high temperatures and reactive atmospheres. (Task 4) Evaluate phase stability and thermal expansion of candidate perovskite membranes and develop techniques to support these materials on porous metal structures. (Task 5) Assess the microstructure of membrane materials to evaluate the effects of vacancy-impurity association, defect clusters, and vacancy-dopant association on the membrane performance and stability. (Task 6) Measure kinetics of oxygen uptake and transport in ceramic membrane materials under commercially relevant conditions using isotope labeling techniques.

  17. OXYGEN ABUNDANCES IN CEPHEIDS

    Luck, R. E.; Andrievsky, S. M.; Korotin, S. N.; Kovtyukh, V. V.

    2013-01-01

    Oxygen abundances in later-type stars, and intermediate-mass stars in particular, are usually determined from the [O I] line at 630.0 nm, and to a lesser extent, from the O I triplet at 615.7 nm. The near-IR triplets at 777.4 nm and 844.6 nm are strong in these stars and generally do not suffer from severe blending with other species. However, these latter two triplets suffer from strong non-local thermodynamic equilibrium (NLTE) effects and thus see limited use in abundance analyses. In this paper, we derive oxygen abundances in a large sample of Cepheids using the near-IR triplets from an NLTE analysis, and compare those abundances to values derived from a local thermodynamic equilibrium (LTE) analysis of the [O I] 630.0 nm line and the O I 615.7 nm triplet as well as LTE abundances for the 777.4 nm triplet. All of these lines suffer from line strength problems making them sensitive to either measurement complications (weak lines) or to line saturation difficulties (strong lines). Upon this realization, the LTE results for the [O I] lines and the O I 615.7 nm triplet are in adequate agreement with the abundance from the NLTE analysis of the near-IR triplets.

  18. Sterilization by oxygen plasma

    Moreira, Adir Jose; Mansano, Ronaldo Domingues; Andreoli Pinto, Terezinha de Jesus; Ruas, Ronaldo; Silva Zambon, Luis da; Silva, Monica Valero da; Verdonck, Patrick Bernard

    2004-07-31

    The use of polymeric medical devices has stimulated the development of new sterilization methods. The traditional techniques rely on ethylene oxide, but there are many questions concerning the carcinogenic properties of the ethylene oxide residues adsorbed on the materials after processing. Another common technique is the gamma irradiation process, but it is costly, its safe operation requires an isolated site and it also affects the bulk properties of the polymers. The use of a gas plasma is an elegant alternative sterilization technique. The plasma promotes an efficient inactivation of the micro-organisms, minimises the damage to the materials and presents very little danger for personnel and the environment. Pure oxygen reactive ion etching type of plasmas were applied to inactivate a biologic indicator, the Bacillus stearothermophilus, to confirm the efficiency of this process. The sterilization processes took a short time, in a few minutes the mortality was complete. In situ analysis of the micro-organisms' inactivating time was possible using emission spectrophotometry. The increase in the intensity of the 777.5 nm oxygen line shows the end of the oxidation of the biologic materials. The results were also observed and corroborated by scanning electron microscopy.

  19. High Selectivity Oxygen Delignification

    Arthur J. Ragauskas

    2005-09-30

    The overall objective of this program was to develop improved extended oxygen delignification (EOD) technologies for current U.S. pulp mill operations. This was accomplished by: (1) Identifying pulping conditions that optimize O and OO performance; (2) Identifying structural features of lignin that enhance reactivity towards EOD of high kappa pulps; (3) Identifying factors minimizing carbohydrate degradation and improve pulp strength of EOD high kappa pulps; (4) Developing a simple, reproducible method of quantifying yield gains from EOD; and (5) Developing process conditions that significantly reduce the capital requirements of EOD while optimizing the yield benefits. Key research outcomes included, demonstrating the use of a mini-O sequence such as (E+O)Dkf:0.05(E+O) or Dkf:0.05(E+O)(E+O) without interstage washing could capture approximately 60% of the delignification efficiency of a conventional O-stage without the major capital requirements associated with an O-stage for conventional SW kraft pulps. The rate of formation and loss of fiber charge during an O-stage stage can be employed to maximize net fiber charge. Optimal fiber charge development and delignification are two independent parameters and do not parallel each other. It is possible to utilize an O-stage to enhance overall cellulosic fiber charge of low and high kappa SW kraft pulps which is beneficial for physical strength properties. The application of NIR and multi-variant analysis was developed into a rapid and simple method of determining the yield of pulp from an oxygen delignification stage that has real-world mill applications. A focus point of this program was the demonstration that Kraft pulping conditions and oxygen delignification of high and low-kappa SW and HW pulps are intimately related. Improved physical pulp properties and yield can be delivered by controlling the H-factor and active alkali charge. Low AA softwood kraft pulp with a kappa number 30 has an average improvement of 2% in

  20. Integration and application of optical chemical sensors in microbioreactors.

    Gruber, Pia; Marques, Marco P C; Szita, Nicolas; Mayr, Torsten

    2017-08-08

    The quantification of key variables such as oxygen, pH, carbon dioxide, glucose, and temperature provides essential information for biological and biotechnological applications and their development. Microfluidic devices offer an opportunity to accelerate research and development in these areas due to their small scale, and the fine control over the microenvironment, provided that these key variables can be measured. Optical sensors are well-suited for this task. They offer non-invasive and non-destructive monitoring of the mentioned variables, and the establishment of time-course profiles without the need for sampling from the microfluidic devices. They can also be implemented in larger systems, facilitating cross-scale comparison of analytical data. This tutorial review presents an overview of the optical sensors and their technology, with a view to support current and potential new users in microfluidics and biotechnology in the implementation of such sensors. It introduces the benefits and challenges of sensor integration, including, their application for microbioreactors. Sensor formats, integration methods, device bonding options, and monitoring options are explained. Luminescent sensors for oxygen, pH, carbon dioxide, glucose and temperature are showcased. Areas where further development is needed are highlighted with the intent to guide future development efforts towards analytes for which reliable, stable, or easily integrated detection methods are not yet available.

  1. MITRE sensor layer prototype

    Duff, Francis; McGarry, Donald; Zasada, David; Foote, Scott

    2009-05-01

    The MITRE Sensor Layer Prototype is an initial design effort to enable every sensor to help create new capabilities through collaborative data sharing. By making both upstream (raw) and downstream (processed) sensor data visible, users can access the specific level, type, and quantities of data needed to create new data products that were never anticipated by the original designers of the individual sensors. The major characteristic that sets sensor data services apart from typical enterprise services is the volume (on the order of multiple terabytes) of raw data that can be generated by most sensors. Traditional tightly coupled processing approaches extract pre-determined information from the incoming raw sensor data, format it, and send it to predetermined users. The community is rapidly reaching the conclusion that tightly coupled sensor processing loses too much potentially critical information.1 Hence upstream (raw and partially processed) data must be extracted, rapidly archived, and advertised to the enterprise for unanticipated uses. The authors believe layered sensing net-centric integration can be achieved through a standardize-encapsulate-syndicateaggregate- manipulate-process paradigm. The Sensor Layer Prototype's technical approach focuses on implementing this proof of concept framework to make sensor data visible, accessible and useful to the enterprise. To achieve this, a "raw" data tap between physical transducers associated with sensor arrays and the embedded sensor signal processing hardware and software has been exploited. Second, we encapsulate and expose both raw and partially processed data to the enterprise within the context of a service-oriented architecture. Third, we advertise the presence of multiple types, and multiple layers of data through geographic-enabled Really Simple Syndication (GeoRSS) services. These GeoRSS feeds are aggregated, manipulated, and filtered by a feed aggregator. After filtering these feeds to bring just the type

  2. Dually Fluorescent Sensing of pH and Dissolved Oxygen Using a Membrane Made from Polymerizable Sensing Monomers.

    Tian, Yanqing; Shumway, Bradley R; Youngbull, A Cody; Li, Yongzhong; Jen, Alex K-Y; Johnson, Roger H; Meldrum, Deirdre R

    2010-06-03

    Using a thermal polymerization approach and polymerizable pH and oxygen sensing monomers with green and red emission spectra, respectively, new pH, oxygen, and their dual sensing membranes were prepared using poly(2-hydroxyethyl methacrylate)-co-poly(acrylamide) as a matrix. The sensors were grafted on acrylate-modified quartz glass and characterized under different pH values, oxygen concentrations, ion strengths, temperatures and cell culture media. The pH and oxygen sensors were excited using the same excitation wavelength and exhibited well-separated emission spectra. The pH-sensing films showed good response over the pH range 5.5 to 8.5, corresponding to pK(a) values in the biologically-relevant range between 6.9 and 7.1. The oxygen-sensing films exhibited linear Stern-Volmer quenching responses to dissolved oxygen. As the sensing membranes were prepared using thermally initiated polymerization of sensing moiety-containing monomers, no leaching of the sensors from the membranes to buffers or medium was observed. This advantageous characteristic accounts in part for the sensors' biocompatibility without apparent toxicity to HeLa cells after 40 hours incubation. The dual-sensing membrane was used to measure pH and dissolved oxygen simultaneously. The measured results correlated with the set-point values.

  3. Medical oxygen and air travel.

    Lyznicki, J M; Williams, M A; Deitchman, S D; Howe, J P

    2000-08-01

    This report responds to a resolution that asked the American Medical Association (AMA) to take action to improve airport and airline accommodations for passengers requiring medical oxygen. Information for the report was derived from a search of the MEDLINE database and references listed in pertinent articles, as well as through communications with experts in aerospace and emergency medicine. Based on this information, the AMA Council on Scientific Affairs determined that commercial air travel exposes passengers to altitude-related hypoxia and gas expansion, which may cause some passengers to experience significant symptoms and medical complications during flight. Medical guidelines are available to help physicians evaluate and counsel potential passengers who are at increased risk of inflight hypoxemia. Supplemental oxygen may be needed for some passengers to maintain adequate tissue oxygenation and prevent hypoxemic complications. For safety and security reasons, federal regulations prohibit travelers from using their own portable oxygen system onboard commercial aircraft. Many U.S. airlines supply medical oxygen for use during flight but policies and procedures vary. Oxygen-dependent passengers must make additional arrangements for the use of supplemental oxygen in airports. Uniform standards are needed to specify procedures and equipment for the use of medical oxygen in airports and aboard commercial aircraft. Revision of federal regulations should be considered to accommodate oxygen-dependent passengers and permit them to have an uninterrupted source of oxygen from departure to destination.

  4. Capacitive chemical sensor

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

    2014-05-27

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

  5. The Ringcore Fluxgate Sensor

    Brauer, Peter

    1997-01-01

    A model describing the fundamental working principle of the "ringcore fluxgate sensor" is derived. The model is solely based on geometrical and measurable magnetic properties of the sensor and from this a number of fluxgate phenomenon can be described and estimated. The sensitivity of ringcore...... fluxgate sensors is measured for a large variety of geometries and is for all measurements found to fall between two limits obtained by the fluxgate model. The model is used to explain the zero field odd harmonic output of the fluxgate sensor, called the "feedthrough". By assuming a non ideal sensor...... with spatially distributed magnetization, the model predicts feedthrough signals which exactly reflects the measured signals. The non-linearities in a feedback compensated ringcore fluxgate sensors, called the "transverse field effect", can also be explained by the model. Measurements on stress annealed...

  6. Cryogenic microsize Hall sensors

    Kvitkovic, J.; Polak, M.

    1993-01-01

    Hall sensors have a variety of applications in magnetic field measurements. The active area of the Hall sensor does not play an important role in measuring of homogeneous magnetic field. Actually Hall sensors are widely used to measure profiles of magnetic fields produced by magnetization currents in samples of HTC superconductors, as well as of LTC ones. Similar techniques are used to measure magnetization of both HTC and LTC superconductors. In these cases Hall sensor operates in highly inhomogeneous magnetic fields. Because of that, Hall sensors with very small active area are required. We developed and tested Hall sensors with active area 100 μm x 100 μm - type M and 50 μm x 50 μm - type V. Here we report on the most imporant parameters of these units, as well as on their properties as differential magnetometer. (orig.)

  7. Clementine sensor suite

    Ledebuhr, A.G. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    LLNL designed and built the suite of six miniaturized light-weight space-qualified sensors utilized in the Clementine mission. A major goal of the Clementine program was to demonstrate technologies originally developed for Ballistic Missile Defense Organization Programs. These sensors were modified to gather data from the moon. This overview presents each of these sensors and some preliminary on-orbit performance estimates. The basic subsystems of these sensors include optical baffles to reject off-axis stray light, light-weight ruggedized optical systems, filter wheel assemblies, radiation tolerant focal plane arrays, radiation hardened control and readout electronics and low mass and power mechanical cryogenic coolers for the infrared sensors. Descriptions of each sensor type are given along with design specifications, photographs and on-orbit data collected.

  8. Flexible magnetoimpedance sensor

    Li, Bodong

    2015-03-01

    Flexible magnetoimpedance (MI) sensors fabricated using a NiFe/Cu/NiFe tri-layer on Kapton substrate have been studied. A customized flexible microstrip transmission line was employed to investigate the MI sensors\\'s magnetic field and frequency responses and their dependence on the sensors\\'s deflection. For the first time, the impedance characteristic is obtained through reflection coefficient analysis over a wide range of frequencies from 0.1 MHz to 3 GHz and for deflections ranging from zero curvature to a radius of 7.2 cm. The sensor element maintains a high MI ratio of up to 90% and magnetic sensitivity of up to 9.2%/Oe over different bending curvatures. The relationship between the curvature and material composition is discussed based on the magnetostriction effect and stress simulations. The sensor\\'s large frequency range, simple fabrication process and high sensitivity provide a great potential for flexible electronics and wireless applications.

  9. Working Group Report: Sensors

    Artuso, M.; et al.,

    2013-10-18

    Sensors play a key role in detecting both charged particles and photons for all three frontiers in Particle Physics. The signals from an individual sensor that can be used include ionization deposited, phonons created, or light emitted from excitations of the material. The individual sensors are then typically arrayed for detection of individual particles or groups of particles. Mounting of new, ever higher performance experiments, often depend on advances in sensors in a range of performance characteristics. These performance metrics can include position resolution for passing particles, time resolution on particles impacting the sensor, and overall rate capabilities. In addition the feasible detector area and cost frequently provides a limit to what can be built and therefore is often another area where improvements are important. Finally, radiation tolerance is becoming a requirement in a broad array of devices. We present a status report on a broad category of sensors, including challenges for the future and work in progress to solve those challenges.

  10. Contact stress sensor

    Kotovsky, Jack [Oakland, CA

    2012-02-07

    A contact stress sensor includes one or more MEMS fabricated sensor elements, where each sensor element of includes a thin non-recessed portion, a recessed portion and a pressure sensitive element adjacent to the recessed portion. An electric circuit is connected to the pressure sensitive element. The circuit includes a thermal compensator and a pressure signal circuit element configured to provide a signal upon movement of the pressure sensitive element.

  11. Transient multivariable sensor evaluation

    Vilim, Richard B.; Heifetz, Alexander

    2017-02-21

    A method and system for performing transient multivariable sensor evaluation. The method and system includes a computer system for identifying a model form, providing training measurement data, generating a basis vector, monitoring system data from sensor, loading the system data in a non-transient memory, performing an estimation to provide desired data and comparing the system data to the desired data and outputting an alarm for a defective sensor.

  12. Networked Sensor Arrays

    Tighe, R. J.

    2002-01-01

    A set of independent radiation sensors, coupled with real-time data telemetry, offers the opportunity to run correlation algorithms for the sensor array as well as to incorporate non-radiological data into the system. This may enhance the overall sensitivity of the sensors and provide an opportunity to project the location of a source within the array. In collaboration with Lawrence Livermore National Laboratory (LLNL) and Sandia National Laboratories (SNL), we have conducted field experiments to test a prototype system. Combining the outputs of a set of distributed sensors permits the correlation that the independent sensor outputs. Combined with additional information such as traffic patterns and velocities, this can reduce random/false detections and enhance detection capability. The principle components of such a system include: (1) A set of radiation sensors. These may be of varying type and complexity, including gamma and/or neutron detectors, gross count and spectral-capable sensors, and low to high energy-resolution sensors. (2) A set of non-radiation sensors. These may include sensors such as vehicle presence and imaging sensors. (3) A communications architecture for near real-time telemetry. Depending upon existing infrastructure and bandwidth requirements, this may be a radio or hard-wire based system. (4) A central command console to pole the sensors, correlate their output, and display the data in a meaningful form to the system operator. Both sensitivity and selectivity are important considerations when evaluating the performance of a detection system. Depending on the application, the optimization of sensitivity as well as the rejection of ''nuisance'' radioactive sources may or may not be critical

  13. Bioinspired Sensor Systems

    Manel del Valle

    2011-10-01

    Full Text Available This editorial summarizes and classifies the contributions presented by different authors to the special issue of the journal Sensors dedicated to Bioinspired Sensor Systems. From the coupling of sensor arrays or networks, plus computer processing abilities, new applications to mimic or to complement human senses are arising in the context of ambient intelligence. Principles used, and illustrative study cases have been presented permitting readers to grasp the current status of the field.

  14. Magnetic actuators and sensors

    Brauer, John R

    2014-01-01

    An accessible, comprehensive guide on magnetic actuators and sensors, this fully updated second edition of Magnetic Actuators and Sensors includes the latest advances, numerous worked calculations, illustrations, and real-life applications. Covering magnetics, actuators, sensors, and systems, with updates of new technologies and techniques, this exemplary learning tool emphasizes computer-aided design techniques, especially magnetic finite element analysis, commonly used by today's engineers. Detailed calculations, numerous illustrations, and discussions of discrepancies make this text an inva

  15. Perimeter intrusion sensors

    Eaton, M.J.

    1977-01-01

    To obtain an effective perimeter intrusion detection system requires careful sensor selection, procurement, and installation. The selection process involves a thorough understanding of the unique site features and how these features affect the performance of each type of sensor. It is necessary to develop procurement specifications to establish acceptable sensor performance limits. Careful explanation and inspection of critical installation dimensions is required during on-site construction. The implementation of these activities at a particular site is discussed

  16. Oxygen effect and intracellular oxygen content (adaptation hypothesis)

    Yarmonenko, S P; Ehpshtejn, I M [Akademiya Meditsinskikh Nauk SSSR, Moscow. Onkologicheskij Tsentr

    1977-01-01

    Experimental data indicating that a radiomodifying action of hypoxia is dependent on the ''prehistory'' of the irradiated object are considered. This dependence manifests itself in a decreased protective action of acute hypoxia on the hypoxia-adapted objects. To explain this a hypothesis is proposed connecting a degree of cell radiosensitivity modification, determined by the oxygen effect, with the intracellular oxygen content. The latter, in accord with current ideas, is regulated by variations in the diffusion resistance to oxygen shown by the cytoplasmic membranes depending on the energy level of the cell and the degree of its oxygenation.

  17. Oxygen effect and intracellular oxygen content (adaptation hypothesis)

    Yarmonenko, S.P.; Ehpshtejn, I.M.

    1977-01-01

    Experimental data indicating that a radiomodifying action of hypoxia is dependent on the ''prehistory'' of the irradiated object are considered. This dependence manifests itself in a decreased protective action of acute hypoxia on the hypoxia-adapted objects. To explain this a hypothesis is proposed connecting a degree of cell radiosensitivity modification, determined by the oxygen effect, with the intracellular oxygen content. The latter, in accord with current ideas, is regulated by variations in the diffusion resistance to oxygen shown by the cytoplasmic membranes depending on the energy level of the cell and the degree of its oxygenation

  18. Sensor Access to the Cellular Microenvironment Using the Sensing Cell Culture Flask.

    Kieninger, Jochen; Tamari, Yaara; Enderle, Barbara; Jobst, Gerhard; Sandvik, Joe A; Pettersen, Erik O; Urban, Gerald A

    2018-04-26

    The Sensing Cell Culture Flask (SCCF) is a cell culture monitoring system accessing the cellular microenvironment in 2D cell culture using electrochemical microsensors. The system is based on microfabricated sensor chips embedded in standard cell culture flasks. Ideally, the sensor chips could be equipped with any electrochemical sensor. Its transparency allows optical inspection of the cells during measurement. The surface of the sensor chip is in-plane with the flask surface allowing undisturbed cell growth on the sensor chip. A custom developed rack system allows easy usage of multiple flasks in parallel within an incubator. The presented data demonstrates the application of the SCCF with brain tumor (T98G) and breast cancer (T-47D) cells. Amperometric oxygen sensors were used to monitor cellular respiration with different incubation conditions. Cellular acidification was accessed with potentiometric pH sensors using electrodeposited iridium oxide films. The system itself provides the foundation for electrochemical monitoring systems in 3D cell culture.

  19. Smart sensors and systems

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

    2015-01-01

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

  20. Dynamic Sensor Networks

    Schott, Brian

    2004-01-01

    ...: Declarative Languages and Execution Environment includes topographical soldier interface and a sensor network simulation environment for algorithm development, deployment planning, and operational support. Finally, Task 3...

  1. Palladium Nanoparticle Hydrogen Sensor

    I. Pavlovsky

    2006-12-01

    Full Text Available An innovative hydrogen sensor based on palladium (Pd nanoparticle networks is described in the article. Made by Applied Nanotech Inc. sensor has a fast response time, in the range of seconds, which is increased at 80 °C due to higher hydrogen diffusion rates into the palladium lattice. The low detection limit of the sensor is 10 ppm of H2, and the high limit is 40,000 ppm. This is 100% of a lowest flammability level of hydrogen. This range of sensitivities complies with the requirements that one would expect for a reliable hydrogen sensor.

  2. Smart and Intelligent Sensors

    Lansaw, John; Schmalzel, John; Figueroa, Jorge

    2009-01-01

    John C. Stennis Space Center (SSC) provides rocket engine propulsion testing for NASA's space programs. Since the development of the Space Shuttle, every Space Shuttle Main Engine (SSME) has undergone acceptance testing at SSC before going to Kennedy Space Center (KSC) for integration into the Space Shuttle. The SSME is a large cryogenic rocket engine that uses Liquid Hydrogen (LH2) as the fuel. As NASA moves to the new ARES V launch system, the main engines on the new vehicle, as well as the upper stage engine, are currently base lined to be cryogenic rocket engines that will also use LH2. The main rocket engines for the ARES V will be larger than the SSME, while the upper stage engine will be approximately half that size. As a result, significant quantities of hydrogen will be required during the development, testing, and operation of these rocket engines.Better approaches are needed to simplify sensor integration and help reduce life-cycle costs. 1.Smarter sensors. Sensor integration should be a matter of "plug-and-play" making sensors easier to add to a system. Sensors that implement new standards can help address this problem; for example, IEEE STD 1451.4 defines transducer electronic data sheet (TEDS) templates for commonly used sensors such as bridge elements and thermocouples. When a 1451.4 compliant smart sensor is connected to a system that can read the TEDS memory, all information needed to configure the data acquisition system can be uploaded. This reduces the amount of labor required and helps minimize configuration errors. 2.Intelligent sensors. Data received from a sensor be scaled, linearized; and converted to engineering units. Methods to reduce sensor processing overhead at the application node are needed. Smart sensors using low-cost microprocessors with integral data acquisition and communication support offer the means to add these capabilities. Once a processor is embedded, other features can be added; for example, intelligent sensors can make

  3. Microfabricated Formaldehyde Gas Sensors

    Karen C. Cheung

    2009-11-01

    Full Text Available Formaldehyde is a volatile organic compound that is widely used in textiles, paper, wood composites, and household materials. Formaldehyde will continuously outgas from manufactured wood products such as furniture, with adverse health effects resulting from prolonged low-level exposure. New, microfabricated sensors for formaldehyde have been developed to meet the need for portable, low-power gas detection. This paper reviews recent work including silicon microhotplates for metal oxide-based detection, enzyme-based electrochemical sensors, and nanowire-based sensors. This paper also investigates the promise of polymer-based sensors for low-temperature, low-power operation.

  4. Luminescence materials for pH and oxygen sensing in microbial cells - structures, optical properties, and biological applications.

    Zou, Xianshao; Pan, Tingting; Chen, Lei; Tian, Yanqing; Zhang, Weiwen

    2017-09-01

    Luminescence including fluorescence and phosphorescence sensors have been demonstrated to be important for studying cell metabolism, and diagnosing diseases and cancer. Various design principles have been employed for the development of sensors in different formats, such as organic molecules, polymers, polymeric hydrogels, and nanoparticles. The integration of the sensing with fluorescence imaging provides valuable tools for biomedical research and applications at not only bulk-cell level but also at single-cell level. In this article, we critically reviewed recent progresses on pH, oxygen, and dual pH and oxygen sensors specifically for their application in microbial cells. In addition, we focused not only on sensor materials with different chemical structures, but also on design and applications of sensors for better understanding cellular metabolism of microbial cells. Finally, we also provided an outlook for future materials design and key challenges in reaching broad applications in microbial cells.

  5. On-line chemical sensors for applications in fast reactors

    Jayaraman, V.

    2015-01-01

    Hydrogen sensors are essential components of fast reactor sodium circuits. These sensors are needed in fast reactors for the immediate detection of any steam leak into sodium during reactor operation which can lead to failure of steam generator. Depending on the operating power of the reactor, sodium-water reaction results in either an increase in dissolved hydrogen level in sodium or an increase in hydrogen content of argon cover gas used above sodium coolant. Hence, on-line monitoring of hydrogen continuously in sodium and cover circuits helps in detection of any steam leak. In the event of accidental leak of high temperature sodium, it reacts with oxygen and moisture in air leading to sodium fires. These fires produce sodium aerosol containing oxides of sodium (Na 2 O and Na 2 O 2 ) and NaOH. For early detection of sodium fires, sensor systems based on sodium ionization detector, pH measurement and modulation of conductivity of graphite films are known in the literature. This presentation deals with the development of on-line sensors for these two applications. A diffusion based sensor using a thin walled nickel coil at 773 K and a sensitive thermal conductivity detector (TCD) has been developed for monitoring hydrogen levels in argon cover gas. This sensor has a lower detection limit of 30 ppm of hydrogen in argon. To extend the detection limit of the sensor, a surface conductivity based sensor has been developed which makes use of a thin film of semi-conducting tin oxide. Integration of this sensor with the TCD, can extend the lower detection limit to 2 ppm of hydrogen in cover gas. Electrochemical sensor based on sodium-beta-alumina has been designed, fabricated and its performance in laboratory and industrial environment was evaluated. This paper presents the logical development of these sensors highlighting their merits and limitations

  6. Measuring oxidation processes: Atomic oxygen flux monitor

    Anon.

    1991-01-01

    Of the existing 95 high-energy accelerators in the world, the Stanford Linear Collider (SLC) at the Stanford Linear Accelerator Center (SLAC) is the only one of the linear-collider type, where electrons and positrons are smashed together at energies of 50 GeV using linear beams instead of beam rings for achieving interactions. Use of a collider eliminates energy losses in the form of x-rays due to the curved trajectory of the rings, a phenomena known as bremsstrauhlung. Because these losses are eliminated, higher interaction energies are reached. Consequently the SLC produced the first Z particle in quantities large enough to allow measurement of its physical properties with some accuracy. SLAC intends to probe still deeper into the structure of matter by next polarizing the electrons in the beam. The surface of the source for these polarized particles, typically gallium arsenide, must be kept clean of contaminants. One method for accomplishing this task requires the oxidation of the surface, from which the oxidized contaminants are later boiled off. The technique requires careful measurement of the oxidation process. SLAC researchers have developed a technique for measuring the atomic oxygen flux in this process. The method uses a silver film on a quartz-crystal, deposition-rate monitor. Measuring the initial oxidation rate of the silver, which is proportional to the atomic oxygen flux, determines a lower limit on that flux in the range of 10 13 to 10 17 atoms per square centimeter per second. Furthermore, the deposition is reversible by exposing the sensor to atomic hydrogen. This technique has wider applications to processes in solid-state and surface physics as well as surface chemistry. In semiconductor manufacturing where a precise thickness of oxide must be deposited, this technique could be used to monitor the critical flux of atomic oxygen in the process

  7. Oxygen Reduction on Platinum

    Nesselberger, Markus

    . The influence of the ion adsorption strength, which is observed in the “particle size studies” on the oxygen reduction rate on Pt/C catalysts, is further investigated under similar reaction conditions by infrared spectroscopy. The designed in situ electrochemical ATR-FTIR setup features a high level...... of instrument automation and online data treatment, and provides welldefined mass transport conditions enabling kinetic measurements. A modified electrochemical / spectroscopic interface is presented allowing the exclusive investigation of the Pt/C catalyst layer. Three types of potential dependent adsorption...... adsorption on Pt does not block the ORR directly. Instead, the onset of oxide formation with the concomitant conversion of the anion adsorbate layer is the decisive blocking mechanism....

  8. Reactive Oxygen Species

    Franchina, Davide G.; Dostert, Catherine; Brenner, Dirk

    2018-01-01

    T cells are a central component of defenses against pathogens and tumors. Their effector functions are sustained by specific metabolic changes that occur upon activation, and these have been the focus of renewed interest. Energy production inevitably generates unwanted products, namely reactive...... and transcription factors, influencing the outcome of the T cell response. We discuss here how ROS can directly fine-tune metabolism and effector functions of T cells....... oxygen species (ROS), which have long been known to trigger cell death. However, there is now evidence that ROS also act as intracellular signaling molecules both in steady-state and upon antigen recognition. The levels and localization of ROS contribute to the redox modeling of effector proteins...

  9. OXYGEN TRANSPORT CERAMIC MEMBRANES

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2001-01-01

    Conversion of natural gas to liquid fuels and chemicals is a major goal for the Nation as it enters the 21st Century. Technically robust and economically viable processes are needed to capture the value of the vast reserves of natural gas on Alaska's North Slope, and wean the Nation from dependence on foreign petroleum sources. Technologies that are emerging to fulfill this need are all based syngas as an intermediate. Syngas (a mixture of hydrogen and carbon monoxide) is a fundamental building block from which chemicals and fuels can be derived. Lower cost syngas translates directly into more cost-competitive fuels and chemicals. The currently practiced commercial technology for making syngas is either steam methane reforming (SMR) or a two-step process involving cryogenic oxygen separation followed by natural gas partial oxidation (POX). These high-energy, capital-intensive processes do not always produce syngas at a cost that makes its derivatives competitive with current petroleum-based fuels and chemicals. This project has the following 6 main tasks: Task 1--Design, fabricate and evaluate ceramic to metal seals based on graded ceramic powder/metal braze joints. Task 2--Evaluate the effect of defect configuration on ceramic membrane conductivity and long term chemical and structural stability. Task 3--Determine materials mechanical properties under conditions of high temperatures and reactive atmospheres. Task 4--Evaluate phase stability and thermal expansion of candidate perovskite membranes and develop techniques to support these materials on porous metal structures. Task 5--Assess the microstructure of membrane materials to evaluate the effects of vacancy-impurity association, defect clusters, and vacancy-dopant association on the membrane performance and stability. Task 6--Measure kinetics of oxygen uptake and transport in ceramic membrane materials under commercially relevant conditions using isotope labeling techniques

  10. Mitochondrial Respiration and Oxygen Tension.

    Shaw, Daniel S; Meitha, Karlia; Considine, Michael J; Foyer, Christine H

    2017-01-01

    Measurements of respiration and oxygen tension in plant organs allow a precise understanding of mitochondrial capacity and function within the context of cellular oxygen metabolism. Here we describe methods that can be routinely used for the isolation of intact mitochondria, and the determination of respiratory electron transport, together with techniques for in vivo determination of oxygen tension and measurement of respiration by both CO 2 production and O 2 consumption that enables calculation of the respiratory quotient [CO 2 ]/[O 2 ].

  11. Oxygen-reducing catalyst layer

    O'Brien, Dennis P [Maplewood, MN; Schmoeckel, Alison K [Stillwater, MN; Vernstrom, George D [Cottage Grove, MN; Atanasoski, Radoslav [Edina, MN; Wood, Thomas E [Stillwater, MN; Yang, Ruizhi [Halifax, CA; Easton, E Bradley [Halifax, CA; Dahn, Jeffrey R [Hubley, CA; O'Neill, David G [Lake Elmo, MN

    2011-03-22

    An oxygen-reducing catalyst layer, and a method of making the oxygen-reducing catalyst layer, where the oxygen-reducing catalyst layer includes a catalytic material film disposed on a substrate with the use of physical vapor deposition and thermal treatment. The catalytic material film includes a transition metal that is substantially free of platinum. At least one of the physical vapor deposition and the thermal treatment is performed in a processing environment comprising a nitrogen-containing gas.

  12. Oxygen potentials of transuranium oxides

    Haruyoshi Otobe; Mituso Akabori; Arai Yasuo; Kazuo Minato

    2008-01-01

    The oxygen potentials of pyrochlore-type Pu 2 Zr 2 O 7+y , fluorite-type (Pu 0.5 Zr 0.5 )O 2-x and AmO 2-x have been measured by the electromotive force (EMF) method with a zirconia solid-electrolyte. The oxygen potentials of these oxides were reviewed. The phase relations, microstructure, equilibrium state of these oxides were discussed, referring to the isothermal curve of the oxygen potentials. (authors)

  13. Biofouling protection for marine environmental sensors

    L. Delauney

    2010-05-01

    Full Text Available These days, many marine autonomous environment monitoring networks are set up in the world. These systems take advantage of existing superstructures such as offshore platforms, lightships, piers, breakwaters or are placed on specially designed buoys or underwater oceanographic structures. These systems commonly use various sensors to measure parameters such as dissolved oxygen, turbidity, conductivity, pH or fluorescence. Emphasis has to be put on the long term quality of measurements, yet sensors may face very short-term biofouling effects. Biofouling can disrupt the quality of the measurements, sometimes in less than a week.

    Many techniques to prevent biofouling on instrumentation are listed and studied by researchers and manufacturers. Very few of them are implemented on instruments and of those very few have been tested in situ on oceanographic sensors for deployment of at least one or two months.

    This paper presents a review of techniques used to protect against biofouling of in situ sensors and gives a short list and description of promising techniques.

  14. Oxygen diffusion and oxygen effect in tumor tissue

    Eissa, H.M.; Hehn, G.

    1979-06-01

    The diffusion of oxygen in tumor cords of bronchus carcinoma of the lung have been studied with refined computer methods for solving the diffusion equation in axis symmetric tumor structures. In this tumor configuration we may find three different regions consisting of euoxic cells, hypoxic tumor cells and necrotic parts. In the case of oxygen supply from a capillary inside a cylinder of tumor tissue with radius 200 μm or in a tumor cord of radius 300 μm with oxygen supply by capillaries outside, we get a relation of well oxygenated cells to hypoxic cells approximately as 1:8 or as 1:1.1 respectively. Of course most of the tumor cords observed in histological slices have smaller diameters, so that an average of approximately 20% hypoxic cells can be assumed. Based on the work of Ardenne, the diffusion of oxygen and glucose in a tumor of type DS-carcinosarcom has been investigated in both intact tumor and tumor treated with ionizing radiation. We can show that a strong reoxygenation effect takes place in that the well supplied regions may increase in some tumor configurations up to a factor of four by volume. The biological consequences of the oxygen pressure determined in tumor cells are discussed in detail. The investigation of oxygen diffusion in the intercapillary tumor region should give a quantitative physical basis for considering the oxygen effect with the aim to explain the advantages of neutron therapy against conventional radiotherapy. (orig./MG) [de

  15. Integration of oxygen membranes for oxygen production in cement plants

    Puig Arnavat, Maria; Søgaard, Martin; Hjuler, Klaus

    2015-01-01

    The present paper describes the integration of oxygen membranes in cement plants both from an energy, exergy and economic point of view. Different configurations for oxygen enrichment of the tertiary air for combustion in the pre-calciner and full oxy-fuel combustion in both pre-calciner and kiln...

  16. Design a Wearable Device for Blood Oxygen Concentration and Temporal Heart Beat Rate

    Myint, Cho Zin; Barsoum, Nader; Ing, Wong Kiing

    2010-06-01

    The wireless network technology is increasingly important in healthcare as a result of the aging population and the tendency to acquire chronic disease such as heart attack, high blood pressure amongst the elderly. A wireless sensor network system that has the capability to monitor physiological sign such as SpO2 (Saturation of Arterial Oxygen) and heart beat rate in real-time from the human's body is highlighted in this study. This research is to design a prototype sensor network hardware, which consists of microcontroller PIC18F series and transceiver unit. The sensor is corporate into a wearable body sensor network which is small in size and easy to use. The sensor allows a non invasive, real time method to provide information regarding the health of the body. This enables a more efficient and economical means for managing the health care of the population.

  17. Enhancement of gas sensor response of nanocrystalline zinc oxide for ammonia by plasma treatment

    Hou, Yue; Jayatissa, Ahalapitiya H.

    2014-01-01

    The effect of oxygen plasma treatment on nanocrystalline ZnO thin film based gas sensor was investigated. ZnO thin films were synthesized on alkali-free glass substrates by a sol–gel process. ZnO thin films were treated with oxygen plasma to change the number of vacancies/defects in ZnO. The effect of oxygen plasma on the structural, electrical, optical and gas sensing properties was investigated as a function of plasma treatment time. The results suggest that the microstructure and the surface morphology can be tuned by oxygen plasma treatment. The optical transmission in the visible range varies after the oxygen plasma treatment. Moreover, it is found that the oxygen plasma has significant impact on the electrical properties of ZnO thin films indicating a variation of resistivity. The oxygen plasma treated ZnO thin film exhibits an enhanced sensing response towards NH 3 in comparison with that of the as-deposited ZnO sensor. When compared with the as-deposited ZnO film, the sensing response was improved by 50% for the optimum oxygen plasma treatment time of 8 min. The selectivity of 8 min plasma treated ZnO sensor was also examined for an important industrial gas mixture of H 2 , CH 4 and NH 3 .

  18. Microelectronic temperature sensor; silicon temperature sensor

    Beitner, M.; Kanert, W.; Reichert, H.

    1982-01-01

    The goal of this work was to develop a silicon temperature sensor with a sensitivity and a reliability as high and a tolerance as small as possible, for use in measurement and control. By employing the principle of spreading-resistance, using silicon doped by neutron transmutation, and trimming of the single wafer tolerances of resistance less than +- 5% can be obtained; overstress tests yielded a long-term stability better than 0.2%. Some applications show the advantageous use of this sensor. (orig.) [de

  19. Method and apparatus for monitoring oxygen partial pressure in air masks

    Kelly, Mark E. (Inventor); Pettit, Donald R. (Inventor)

    2006-01-01

    Method and apparatus are disclosed for monitoring an oxygen partial pressure in an air mask and providing a tactile warning to the user. The oxygen partial pressure in the air mask is detected using an electrochemical sensor, the output signal from which is provided to a comparator. The comparator compares the output signal with a preset reference value or range of values representing acceptable oxygen partial pressures. If the output signal is different than the reference value or outside the range of values, the air mask is vibrated by a vibrating motor to alert the user to a potentially hypoxic condition.

  20. Arterial blood oxygen saturation during blood pressure cuff-induced hypoperfusion

    Kyriacou, P A; Shafqat, K; Pal, S K

    2007-01-01

    Pulse oximetry has been one of the most significant technological advances in clinical monitoring in the last two decades. Pulse oximetry is a non-invasive photometric technique that provides information about the arterial blood oxygen saturation (SpO 2 ) and heart rate, and has widespread clinical applications. When peripheral perfusion is poor, as in states of hypovolaemia, hypothermia and vasoconstriction, oxygenation readings become unreliable or cease. The problem arises because conventional pulse oximetry sensors must be attached to the most peripheral parts of the body, such as finger, ear or toe, where pulsatile flow is most easily compromised. Pulse oximeters estimate arterial oxygen saturation by shining light at two different wavelengths, red and infrared, through vascular tissue. In this method the ac pulsatile photoplethysmographic (PPG) signal associated with cardiac contraction is assumed to be attributable solely to the arterial blood component. The amplitudes of the red and infrared ac PPG signals are sensitive to changes in arterial oxygen saturation because of differences in the light absorption of oxygenated and deoxygenated haemoglobin at these two wavelengths. From the ratios of these amplitudes, and the corresponding dc photoplethysmographic components, arterial blood oxygen saturation (SpO 2 ) is estimated. Hence, the technique of pulse oximetry relies on the presence of adequate peripheral arterial pulsations, which are detected as photoplethysmographic (PPG) signals. The aim of this study was to investigate the effect of pressure cuff-induced hypoperfusion on photoplethysmographic signals and arterial blood oxygen saturation using a custom made finger blood oxygen saturation PPG/SpO 2 sensor and a commercial finger pulse oximeter. Blood oxygen saturation values from the custom oxygen saturation sensor and a commercial finger oxygen saturation sensor were recorded from 14 healthy volunteers at various induced brachial pressures. Both pulse

  1. Arterial blood oxygen saturation during blood pressure cuff-induced hypoperfusion

    Kyriacou, P A [School of Engineering and Mathematical Sciences, City University, London EC1V 0HB (United Kingdom); Shafqat, K [School of Engineering and Mathematical Sciences, City University, London EC1V 0HB (United Kingdom); Pal, S K [St Andrew' s Centre for Plastic Surgery and Burns, Broomfield Hospital, Chelmsford, CM1 7ET (United Kingdom)

    2007-10-15

    Pulse oximetry has been one of the most significant technological advances in clinical monitoring in the last two decades. Pulse oximetry is a non-invasive photometric technique that provides information about the arterial blood oxygen saturation (SpO{sub 2}) and heart rate, and has widespread clinical applications. When peripheral perfusion is poor, as in states of hypovolaemia, hypothermia and vasoconstriction, oxygenation readings become unreliable or cease. The problem arises because conventional pulse oximetry sensors must be attached to the most peripheral parts of the body, such as finger, ear or toe, where pulsatile flow is most easily compromised. Pulse oximeters estimate arterial oxygen saturation by shining light at two different wavelengths, red and infrared, through vascular tissue. In this method the ac pulsatile photoplethysmographic (PPG) signal associated with cardiac contraction is assumed to be attributable solely to the arterial blood component. The amplitudes of the red and infrared ac PPG signals are sensitive to changes in arterial oxygen saturation because of differences in the light absorption of oxygenated and deoxygenated haemoglobin at these two wavelengths. From the ratios of these amplitudes, and the corresponding dc photoplethysmographic components, arterial blood oxygen saturation (SpO{sub 2}) is estimated. Hence, the technique of pulse oximetry relies on the presence of adequate peripheral arterial pulsations, which are detected as photoplethysmographic (PPG) signals. The aim of this study was to investigate the effect of pressure cuff-induced hypoperfusion on photoplethysmographic signals and arterial blood oxygen saturation using a custom made finger blood oxygen saturation PPG/SpO{sub 2} sensor and a commercial finger pulse oximeter. Blood oxygen saturation values from the custom oxygen saturation sensor and a commercial finger oxygen saturation sensor were recorded from 14 healthy volunteers at various induced brachial pressures

  2. Arterial blood oxygen saturation during blood pressure cuff-induced hypoperfusion

    Kyriacou, P. A.; Shafqat, K.; Pal, S. K.

    2007-10-01

    Pulse oximetry has been one of the most significant technological advances in clinical monitoring in the last two decades. Pulse oximetry is a non-invasive photometric technique that provides information about the arterial blood oxygen saturation (SpO2) and heart rate, and has widespread clinical applications. When peripheral perfusion is poor, as in states of hypovolaemia, hypothermia and vasoconstriction, oxygenation readings become unreliable or cease. The problem arises because conventional pulse oximetry sensors must be attached to the most peripheral parts of the body, such as finger, ear or toe, where pulsatile flow is most easily compromised. Pulse oximeters estimate arterial oxygen saturation by shining light at two different wavelengths, red and infrared, through vascular tissue. In this method the ac pulsatile photoplethysmographic (PPG) signal associated with cardiac contraction is assumed to be attributable solely to the arterial blood component. The amplitudes of the red and infrared ac PPG signals are sensitive to changes in arterial oxygen saturation because of differences in the light absorption of oxygenated and deoxygenated haemoglobin at these two wavelengths. From the ratios of these amplitudes, and the corresponding dc photoplethysmographic components, arterial blood oxygen saturation (SpO2) is estimated. Hence, the technique of pulse oximetry relies on the presence of adequate peripheral arterial pulsations, which are detected as photoplethysmographic (PPG) signals. The aim of this study was to investigate the effect of pressure cuff-induced hypoperfusion on photoplethysmographic signals and arterial blood oxygen saturation using a custom made finger blood oxygen saturation PPG/SpO2 sensor and a commercial finger pulse oximeter. Blood oxygen saturation values from the custom oxygen saturation sensor and a commercial finger oxygen saturation sensor were recorded from 14 healthy volunteers at various induced brachial pressures. Both pulse

  3. Medical Sensor Network Infrastructures

    Andersen, Jacob

    researchers have been developing power-efficient security mechanisms for sensor networks. However, most of this work ignores the special usability demands from the clinical use-scenarios: set-up must be fast, and key pre-distribution is problematic if disposable sensors are discarded after being used for only...

  4. Sensors in Education

    Van Rosmalen, Peter; Schneider, Jan; Börner, Dirk

    2014-01-01

    Sensors rapidly become available both for personal as well as scientific use. A wide range of applications exists for personal use e.g. safety in and around the house, sport, fitness and health. In this workshop we will explore how sensors are (can be) used in education. We start with an

  5. Nanophotonic Image Sensors.

    Chen, Qin; Hu, Xin; Wen, Long; Yu, Yan; Cumming, David R S

    2016-09-01

    The increasing miniaturization and resolution of image sensors bring challenges to conventional optical elements such as spectral filters and polarizers, the properties of which are determined mainly by the materials used, including dye polymers. Recent developments in spectral filtering and optical manipulating techniques based on nanophotonics have opened up the possibility of an alternative method to control light spectrally and spatially. By integrating these technologies into image sensors, it will become possible to achieve high compactness, improved process compatibility, robust stability and tunable functionality. In this Review, recent representative achievements on nanophotonic image sensors are presented and analyzed including image sensors with nanophotonic color filters and polarizers, metamaterial-based THz image sensors, filter-free nanowire image sensors and nanostructured-based multispectral image sensors. This novel combination of cutting edge photonics research and well-developed commercial products may not only lead to an important application of nanophotonics but also offer great potential for next generation image sensors beyond Moore's Law expectations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Sensor technology foresight

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

    2001-01-01

    heavily impacted by new sensor technology. It also appears that new sensor technology will affect food processing and the environment sector. Some impact is made on sectors such as agriculture, chemical engineering, domestic and otherappliances, security and defence, transport, and energy. Less impact...

  7. ALC Rooftop Sensor System

    2017-10-31

    Department of the Army position unless so designated by other authorized documents. Citation of manufacturer’s or trade names does not constitute an... Interior view of the new sensor box ...................................................... 3 Fig. 4 Interior of original sensor box...7 Fig. 10 Interior of fiber patch panel .................................................................. 7 Fig. 11

  8. Stretch Sensor Device

    2013-01-01

    The invention relates to a method for determining stretch values and movement of body parts, e.g. a foot, by analysing stretch data from a stretch sensor. By analysing data from the stretch sensor it is possible to determine stretch samples which are associated with particular motion phases...

  9. Magnetic sensor device

    2009-01-01

    The present invention provides a sensor device and a method for detg. the presence and/or amt. of target moieties in a sample fluid, the target moieties being labeled with magnetic or magnetizable objects. The sensor device comprises a magnetic field generating means adapted for applying a retention

  10. Aggregating Linked Sensor Data

    Stasch, Christoph; Schade, Sven; Llaves, Alejandro; Janowicz, K.; Bröring, Arne; Taylor, Kerry; Ayyagari, Arun; De Roure, David

    2011-01-01

    Sensor observations are usually oered in relation to a specific purpose, e.g., for reporting fine dust emissions, following strict procedures, and spatio-temporal scales. Consequently, the huge amount of data gathered by today's public and private sensor networks is most often not reused outside of

  11. Sensor Data Fusion

    Plascencia, Alfredo; Stepán, Petr

    2006-01-01

    The main contribution of this paper is to present a sensor fusion approach to scene environment mapping as part of a Sensor Data Fusion (SDF) architecture. This approach involves combined sonar array with stereo vision readings.  Sonar readings are interpreted using probability density functions...

  12. Multifunctional optical sensor

    2010-01-01

    The invention relates to a multifunctional optical sensor, having at least 2 areas which independently react to different input parameters, the sensor comprising a substrate and a polymeric layer comprising polymerized liquid crystal monomers having an ordered morphology, wherein the color, the

  13. Sensor Alerting Capability

    Henriksson, Jakob; Bermudez, Luis; Satapathy, Goutam

    2013-04-01

    There is a large amount of sensor data generated today by various sensors, from in-situ buoys to mobile underwater gliders. Providing sensor data to the users through standardized services, language and data model is the promise of OGC's Sensor Web Enablement (SWE) initiative. As the amount of data grows it is becoming difficult for data providers, planners and managers to ensure reliability of data and services and to monitor critical data changes. Intelligent Automation Inc. (IAI) is developing a net-centric alerting capability to address these issues. The capability is built on Sensor Observation Services (SOSs), which is used to collect and monitor sensor data. The alerts can be configured at the service level and at the sensor data level. For example it can alert for irregular data delivery events or a geo-temporal statistic of sensor data crossing a preset threshold. The capability provides multiple delivery mechanisms and protocols, including traditional techniques such as email and RSS. With this capability decision makers can monitor their assets and data streams, correct failures or be alerted about a coming phenomena.

  14. Electrocatalytic glucose sensor

    Gebhardt, U; Luft, G; Mund, K; Preidel, W; Richter, G J

    1983-01-01

    An artificial pancreas consists of an insulin depot, a dosage unit and a glucose sensor. The measurement of the actual glucose concentration in blood is still an unsolved problem. Two methods are described for an electrocatalytic glucose sensor. Under the interfering action of amino acids and urea in-vitro measurements show an error of between 10% and 20%.

  15. Pressure Measurement Sensor

    1997-01-01

    FFPI Industries Inc. is the manufacturer of fiber-optic sensors that furnish accurate pressure measurements in internal combustion chambers. Such an assessment can help reduce pollution emitted by these engines. A chief component in the sensor owes its seven year- long development to Lewis Research Center funding to embed optical fibers and sensors in metal parts. NASA support to Texas A&M University played a critical role in developing this fiber optic technology and led to the formation of FFPI Industries and the production of fiber sensor products. The simple, rugged design of the sensor offers the potential for mass production at low cost. Widespread application of the new technology is forseen, from natural gas transmission, oil refining and electrical power generation to rail transport and the petrochemical paper product industry.

  16. An electrokinetic pressure sensor

    Kim, Dong-Kwon; Kim, Sung Jin; Kim, Duckjong

    2008-01-01

    A new concept for a micro pressure sensor is demonstrated. The pressure difference between the inlet and the outlet of glass nanochannels is obtained by measuring the electrokinetically generated electric potential. To demonstrate the proposed concept, experimental investigations are performed for 100 nm wide nanochannels with sodium chloride solutions having various concentrations. The proposed pressure sensor is able to measure the pressure difference within a 10% deviation from linearity. The sensitivity of the electrokinetic pressure sensor with 10 −5 M sodium chloride solution is 18.5 µV Pa −1 , which is one order of magnitude higher than that of typical diaphragm-based pressure sensors. A numerical model is presented for investigating the effects of the concentration and the channel width on the sensitivity of the electrokinetic pressure sensor. Numerical results show that the sensitivity increases as the concentration decreases and the channel width increases

  17. 2-Sensor Problem

    Michael Segal

    2004-11-01

    Full Text Available Abstract: Ad-hoc networks of sensor nodes are in general semi-permanently deployed. However, the topology of such networks continuously changes over time, due to the power of some sensors wearing out to new sensors being inserted into the network, or even due to designers moving sensors around during a network re-design phase (for example, in response to a change in the requirements of the network. In this paper, we address the problem of covering a given path by a limited number of sensors — in our case to two, and show its relation to the well-studied matrix multiplication problem.

  18. Fiber optic gas sensor

    Chen, Peng (Inventor); Buric, Michael P. (Inventor); Swinehart, Philip R. (Inventor); Maklad, Mokhtar S. (Inventor)

    2010-01-01

    A gas sensor includes an in-fiber resonant wavelength device provided in a fiber core at a first location. The fiber propagates a sensing light and a power light. A layer of a material is attached to the fiber at the first location. The material is able to absorb the gas at a temperature dependent gas absorption rate. The power light is used to heat the material and increases the gas absorption rate, thereby increasing sensor performance, especially at low temperatures. Further, a method is described of flash heating the gas sensor to absorb more of the gas, allowing the sensor to cool, thereby locking in the gas content of the sensor material, and taking the difference between the starting and ending resonant wavelengths as an indication of the concentration of the gas in the ambient atmosphere.

  19. Cryogenic, Absolute, High Pressure Sensor

    Chapman, John J. (Inventor); Shams. Qamar A. (Inventor); Powers, William T. (Inventor)

    2001-01-01

    A pressure sensor is provided for cryogenic, high pressure applications. A highly doped silicon piezoresistive pressure sensor is bonded to a silicon substrate in an absolute pressure sensing configuration. The absolute pressure sensor is bonded to an aluminum nitride substrate. Aluminum nitride has appropriate coefficient of thermal expansion for use with highly doped silicon at cryogenic temperatures. A group of sensors, either two sensors on two substrates or four sensors on a single substrate are packaged in a pressure vessel.

  20. Cryogenic High Pressure Sensor Module

    Chapman, John J. (Inventor); Shams, Qamar A. (Inventor); Powers, William T. (Inventor)

    1999-01-01

    A pressure sensor is provided for cryogenic, high pressure applications. A highly doped silicon piezoresistive pressure sensor is bonded to a silicon substrate in an absolute pressure sensing configuration. The absolute pressure sensor is bonded to an aluminum nitride substrate. Aluminum nitride has appropriate coefficient of thermal expansion for use with highly doped silicon at cryogenic temperatures. A group of sensors, either two sensors on two substrates or four sensors on a single substrate are packaged in a pressure vessel.

  1. Uranium dioxide sintering Kinetics and mechanisms under controlled oxygen potentials

    Freitas, C.T. de.

    1980-06-01

    The initial, intermediate, and final sintering stages of uranium dioxide were investigated as a function of stoichiometry and temperature by following the kinetics of the sintering reaction. Stoichiometry was controlled by means of the oxygen potential of the sintering atmosphere, which was measured continuously by solid-state oxygen sensors. Included in the kinetic study were microspheres originated from UO 2 gels and UO 2 pellets produced by isostatic pressing ceramic grade powders. The microspheres sintering behavior was examined using hot-stage microscopy and a specially designed high-temperature, controlled atmosphere furnace. This same furnace was employed as part of an optical dilatometer, which was utilized in the UO 2 pellet sintering investigations. For controlling the deviations from stoichiometry during heat treatment, the oxygen partial pressure in the sintering atmosphere was varied by passing the gas through a Cu-Ti-Cu oxygen trap. The trap temperature determined the oxygen partial pressure of the outflowing mixture. Dry hydrogen was also used in some of the UO sub(2+x) sintering experiments. The determination of diametrial shrinkages and sintering indices was made utilizing high-speed microcinematography and ultra-microbalance techniques. It was observed that the oxygen potential has a substantial influence on the kinetics of the three sintering stages. The control of the sintering atmosphere oxygen partial pressure led to very fast densification of UO sub(2+x). Values in the interval 95.0 to 99.5% of theoretical density were reached in less than one minute. Uranium volume diffusion is the dominant mechanism in the initial and intermediate sintering stages. For the final stage, uranium grain boundary diffusion was found to be the main sintering mechanism. (Author) [pt

  2. A highly accurate method for determination of dissolved oxygen: Gravimetric Winkler method

    Helm, Irja; Jalukse, Lauri; Leito, Ivo

    2012-01-01

    Highlights: ► Probably the most accurate method available for dissolved oxygen concentration measurement was developed. ► Careful analysis of uncertainty sources was carried out and the method was optimized for minimizing all uncertainty sources as far as practical. ► This development enables more accurate calibration of dissolved oxygen sensors for routine analysis than has been possible before. - Abstract: A high-accuracy Winkler titration method has been developed for determination of dissolved oxygen concentration. Careful analysis of uncertainty sources relevant to the Winkler method was carried out and the method was optimized for minimizing all uncertainty sources as far as practical. The most important improvements were: gravimetric measurement of all solutions, pre-titration to minimize the effect of iodine volatilization, accurate amperometric end point detection and careful accounting for dissolved oxygen in the reagents. As a result, the developed method is possibly the most accurate method of determination of dissolved oxygen available. Depending on measurement conditions and on the dissolved oxygen concentration the combined standard uncertainties of the method are in the range of 0.012–0.018 mg dm −3 corresponding to the k = 2 expanded uncertainty in the range of 0.023–0.035 mg dm −3 (0.27–0.38%, relative). This development enables more accurate calibration of electrochemical and optical dissolved oxygen sensors for routine analysis than has been possible before.

  3. Nanowire sensor, sensor array, and method for making the same

    Yun, Minhee (Inventor); Myung, Nosang (Inventor); Vasquez, Richard (Inventor); Homer, Margie (Inventor); Ryan, Margaret (Inventor); Yen, Shiao-Pin (Inventor); Fleurial, Jean-Pierre (Inventor); Bugga, Ratnakumar (Inventor); Choi, Daniel (Inventor); Goddard, William (Inventor)

    2012-01-01

    The present invention relates to a nanowire sensor and method for forming the same. More specifically, the nanowire sensor comprises at least one nanowire formed on a substrate, with a sensor receptor disposed on a surface of the nanowire, thereby forming a receptor-coated nanowire. The nanowire sensor can be arranged as a sensor sub-unit comprising a plurality of homogeneously receptor-coated nanowires. A plurality of sensor subunits can be formed to collectively comprise a nanowire sensor array. Each sensor subunit in the nanowire sensor array can be formed to sense a different stimulus, allowing a user to sense a plurality of stimuli. Additionally, each sensor subunit can be formed to sense the same stimuli through different aspects of the stimulus. The sensor array is fabricated through a variety of techniques, such as by creating nanopores on a substrate and electrodepositing nanowires within the nanopores.

  4. Handheld Broadband Electromagnetic UXO Sensor

    Won, I. J; San Filipo, William A; Marqusee, Jeffrey; Andrews, Anne; Robitaille, George; Fairbanks, Jeffrey; Overbay, Larry

    2005-01-01

    The broadband electromagnetic sensor improvement and demonstration undertaken in this project took the prototype GEM-3 and evolved it into an operational sensor with increased bandwidth and dynamic...

  5. Oxygen therapy for cluster headache

    Petersen, Anja S; Barloese, Mads Cj; Lund, Nunu Lt

    2017-01-01

    -controlled, crossover inpatient study, and 102 CH attacks were treated with 100% oxygen delivered by demand valve oxygen (DVO), O2ptimask or simple mask (15 liters/min) or placebo delivered by DVO for 15 minutes. Primary endpoint: Two-point decrease of pain on a five-point rating scale within 15 minutes. Results Only...

  6. Mars oxygen production system design

    Cotton, Charles E.; Pillow, Linda K.; Perkinson, Robert C.; Brownlie, R. P.; Chwalowski, P.; Carmona, M. F.; Coopersmith, J. P.; Goff, J. C.; Harvey, L. L.; Kovacs, L. A.

    1989-01-01

    The design and construction phase is summarized of the Mars oxygen demonstration project. The basic hardware required to produce oxygen from simulated Mars atmosphere was assembled and tested. Some design problems still remain with the sample collection and storage system. In addition, design and development of computer compatible data acquisition and control instrumentation is ongoing.

  7. Oxygen Effects in Anaerobic Digestion

    Deshai Botheju

    2009-10-01

    Full Text Available Interaction of free oxygen in bio-gasification is a sparsely studied area, apart from the common argument of oxygen being toxic and inhibitory for anaerobic micro-cultures. Some studies have, however, revealed increased solubilisation of organic matter in the presence of some free oxygen in anaerobic digestion. This article analyses these counterbalancing phenomena with a mathematical modelling approach using the widely accepted biochemical model ADM 1. Aerobic oxidation of soluble carbon and inhibition of obligatory anaerobic organisms are modelled using standard saturation type kinetics. Biomass dependent first order hydrolysis kinetics is used to relate the increased hydrolysis rate with oxygen induced increase in biomass growth. The amended model, ADM 1-Ox (oxygen, has 25 state variables and 22 biochemical processes, presented in matrix form. The computer aided simulation tool AQUASIM 2.1 is used to simulate the developed model. Simulation predictions are evaluated against experimental data obtained using a laboratory batch test array comprising miniature anaerobic bio-reactors of 100 ml total volume each, operated under different initial air headspaces giving rise to the different oxygen loading conditions. The reactors were initially fed with a glucose solution and incubated at 35 Celsius, for 563 hours. Under the oxygen load conditions of 22, 44 and 88 mg/L, the ADM1-Ox model simulations predicted the experimental methane potentials quite adequately. Both the experimental data and the simulations suggest a linear reduction of methane potential with respect to the increase in oxygen load within this range.

  8. Environmental science: Oceans lose oxygen

    Gilbert, Denis

    2017-02-01

    Oxygen is essential to most life in the ocean. An analysis shows that oxygen levels have declined by 2% in the global ocean over the past five decades, probably causing habitat loss for many fish and invertebrate species. See Letter p.335

  9. Misconceptions in Reporting Oxygen Saturation

    Toffaletti, John; Zijlstra, Willem G.

    2007-01-01

    BACKGROUND: We describe some misconceptions that have become common practice in reporting blood gas and cooximetry results. In 1980, oxygen saturation was incorrectly redefined in a report of a new instrument for analysis of hemoglobin (Hb) derivatives. Oxygen saturation (sO(2)) was redefined as the

  10. On the Go with Oxygen

    ... for both the patient and the oxygen supply company. There are two types of concentrators: Stationary concentrators plug into an electrical ... stationary unit. If your oxygen needs change, the type of system can ... supply company should explain and demonstrate whatever system you choose. ...

  11. OXYGEN TRANSPORT CERAMIC MEMBRANES

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2002-01-01

    Conversion of natural gas to liquid fuels and chemicals is a major goal for the Nation as it enters the 21st Century. Technically robust and economically viable processes are needed to capture the value of the vast reserves of natural gas on Alaska's North Slope, and wean the Nation from dependence on foreign petroleum sources. Technologies that are emerging to fulfill this need are all based syngas as an intermediate. Syngas (a mixture of hydrogen and carbon monoxide) is a fundamental building block from which chemicals and fuels can be derived. Lower cost syngas translates directly into more cost-competitive fuels and chemicals. The currently practiced commercial technology for making syngas is either steam methane reforming (SMR) or a two-step process involving cryogenic oxygen separation followed by natural gas partial oxidation (POX). These high-energy, capital-intensive processes do not always produce syngas at a cost that makes its derivatives competitive with current petroleum-based fuels and chemicals

  12. Processing of pulse oximeter signals using adaptive filtering and autocorrelation to isolate perfusion and oxygenation components

    Ibey, Bennett; Subramanian, Hariharan; Ericson, Nance; Xu, Weijian; Wilson, Mark; Cote, Gerard L.

    2005-03-01

    A blood perfusion and oxygenation sensor has been developed for in situ monitoring of transplanted organs. In processing in situ data, motion artifacts due to increased perfusion can create invalid oxygenation saturation values. In order to remove the unwanted artifacts from the pulsatile signal, adaptive filtering was employed using a third wavelength source centered at 810nm as a reference signal. The 810 nm source resides approximately at the isosbestic point in the hemoglobin absorption curve where the absorbance of light is nearly equal for oxygenated and deoxygenated hemoglobin. Using an autocorrelation based algorithm oxygenation saturation values can be obtained without the need for large sampling data sets allowing for near real-time processing. This technique has been shown to be more reliable than traditional techniques and proven to adequately improve the measurement of oxygenation values in varying perfusion states.

  13. Roadmap on optical sensors.

    Ferreira, Mário F S; Castro-Camus, Enrique; Ottaway, David J; López-Higuera, José Miguel; Feng, Xian; Jin, Wei; Jeong, Yoonchan; Picqué, Nathalie; Tong, Limin; Reinhard, Björn M; Pellegrino, Paul M; Méndez, Alexis; Diem, Max; Vollmer, Frank; Quan, Qimin

    2017-08-01

    Sensors are devices or systems able to detect, measure and convert magnitudes from any domain to an electrical one. Using light as a probe for optical sensing is one of the most efficient approaches for this purpose. The history of optical sensing using some methods based on absorbance, emissive and florescence properties date back to the 16th century. The field of optical sensors evolved during the following centuries, but it did not achieve maturity until the demonstration of the first laser in 1960. The unique properties of laser light become particularly important in the case of laser-based sensors, whose operation is entirely based upon the direct detection of laser light itself, without relying on any additional mediating device. However, compared with freely propagating light beams, artificially engineered optical fields are in increasing demand for probing samples with very small sizes and/or weak light-matter interaction. Optical fiber sensors constitute a subarea of optical sensors in which fiber technologies are employed. Different types of specialty and photonic crystal fibers provide improved performance and novel sensing concepts. Actually, structurization with wavelength or subwavelength feature size appears as the most efficient way to enhance sensor sensitivity and its detection limit. This leads to the area of micro- and nano-engineered optical sensors. It is expected that the combination of better fabrication techniques and new physical effects may open new and fascinating opportunities in this area. This roadmap on optical sensors addresses different technologies and application areas of the field. Fourteen contributions authored by experts from both industry and academia provide insights into the current state-of-the-art and the challenges faced by researchers currently. Two sections of this paper provide an overview of laser-based and frequency comb-based sensors. Three sections address the area of optical fiber sensors, encompassing both

  14. Roadmap on optical sensors

    Ferreira, Mário F. S.; Castro-Camus, Enrique; Ottaway, David J.; López-Higuera, José Miguel; Feng, Xian; Jin, Wei; Jeong, Yoonchan; Picqué, Nathalie; Tong, Limin; Reinhard, Björn M.; Pellegrino, Paul M.; Méndez, Alexis; Diem, Max; Vollmer, Frank; Quan, Qimin

    2017-08-01

    Sensors are devices or systems able to detect, measure and convert magnitudes from any domain to an electrical one. Using light as a probe for optical sensing is one of the most efficient approaches for this purpose. The history of optical sensing using some methods based on absorbance, emissive and florescence properties date back to the 16th century. The field of optical sensors evolved during the following centuries, but it did not achieve maturity until the demonstration of the first laser in 1960. The unique properties of laser light become particularly important in the case of laser-based sensors, whose operation is entirely based upon the direct detection of laser light itself, without relying on any additional mediating device. However, compared with freely propagating light beams, artificially engineered optical fields are in increasing demand for probing samples with very small sizes and/or weak light-matter interaction. Optical fiber sensors constitute a subarea of optical sensors in which fiber technologies are employed. Different types of specialty and photonic crystal fibers provide improved performance and novel sensing concepts. Actually, structurization with wavelength or subwavelength feature size appears as the most efficient way to enhance sensor sensitivity and its detection limit. This leads to the area of micro- and nano-engineered optical sensors. It is expected that the combination of better fabrication techniques and new physical effects may open new and fascinating opportunities in this area. This roadmap on optical sensors addresses different technologies and application areas of the field. Fourteen contributions authored by experts from both industry and academia provide insights into the current state-of-the-art and the challenges faced by researchers currently. Two sections of this paper provide an overview of laser-based and frequency comb-based sensors. Three sections address the area of optical fiber sensors, encompassing both

  15. Molecularly Imprinted Polypyrrole Based Impedimentric Sensor for Theophylline Determination

    Ratautaite, Vilma; Janssens, Stoffel D.; Haenen, Ken; Nesládek, Milos; Ramanaviciene, Almira; Baleviciute, Ieva; Ramanavicius, Arunas

    2014-01-01

    Highlights: • Sensor based on polypyrrole imprinted by theophylline (MIP) deposited on oxygen terminated boron-doped nanocrystalline diamond was developed. • This structure was applied as impedimetric sensor sensitive for theophylline. • Optimal polymer formation conditions suitable for MIP formation were elaborated. • Some analytical parameters were determined and evaluated. - Abstract: In this study development of impedimetric sensor based on oxygen terminated boron-doped nanocrystalline diamond (B:NCD:O) modified with theophylline imprinted polypyrrole is described. Hydrogen peroxide induced chemical formation of polypyrrole molecularly imprinted by theophylline was applied for the modification of conducting silicon substrate covered by B:NCD:O film. Non-imprinted polypyrrole layer was formed on similar substrate in order to prove efficiency of imprinted polypyrrole. Electrochemical impedance spectroscopy was applied for the evaluation of analyte-induced changes in electrochemical capacitance/resistance. The impact of polymerization duration on the capacitance of impedimetric sensor was estimated. A different impedance behavior was observed at different ratio of polymerized monomer and template molecule in the polymerization media. The influence of ethanol as additive to polymerization media on registered changes in capacitance/resistance was evaluated. Degradation of sensor stored in buffer solution was evaluated

  16. Performance of a digital PCO2/SPO2 ear sensor.

    Kocher, Serge; Rohling, Roman; Tschupp, Andres

    2004-04-01

    For determining the adequacy of ventilation, conventional pulse oximetry should be amended by PaCO2 (= arterial carbon dioxide partial pressure). This study investigates the precision of carbon dioxide measurements of the first digital ear-clip sensor providing continuous non-invasive monitoring of PaCO2, SpO2 (= functional arterial oxygen saturation as estimated with a pulse oximeter) and pulse rate and compares it to two conventional analog oximeters. 30 hypoxemia episodes in 6 adult volunteers were investigated in a standardized protocol. Masimo analog finger sensor, Nellcor analog ear sensor, SenTec digital ear sensor. The difference between PCO2 data (= PaCO2 estimated from the measured PcCO2 based on an algorithm by Severinghaus) (PcCO2 = cutaneous carbon dioxide pressure) and the PaCO2 is clinically unimportant. Therefore, we suggest, the two methods of estimating patient's carbon dioxide status can be used interchangeably. Combined digital SpO2/ PcCO2 ear sensors are very promising to allow for a fast and reliable monitoring of patient's oxygenation, hyper-/hypocapnia and ventilation with one single non-invasive probe. Optimal primary signal processing--amplification and digitalisation within the probe--allow for fast and reliable downstream signal processing algorithms. The resulting short SpO2 response times give the medical staff more time to take appropriate actions.

  17. A novel microbial fuel cell sensor with biocathode sensing element.

    Jiang, Yong; Liang, Peng; Liu, Panpan; Wang, Donglin; Miao, Bo; Huang, Xia

    2017-08-15

    The traditional microbial fuel cell (MFC) sensor with bioanode as sensing element delivers limited sensitivity to toxicity monitoring, restricted application to only anaerobic and organic rich water body, and increased potential fault warning to the combined shock of organic matter/toxicity. In this study, the biocathode for oxygen reduction reaction was employed for the first time as the sensing element in MFC sensor for toxicity monitoring. The results shown that the sensitivity of MFC sensor with biocathode sensing element (7.4±2.0 to 67.5±4.0mA% -1 cm -2 ) was much greater than that showed by bioanode sensing element (3.4±1.5 to 5.5±0.7mA% -1 cm -2 ). The biocathode sensing element achieved the lowest detection limit reported to date using MFC sensor for formaldehyde detection (0.0005%), while the bioanode was more applicable for higher concentration (>0.0025%). There was a quicker response of biocathode sensing element with the increase of conductivity and dissolved oxygen (DO). The biocathode sensing element made the MFC sensor directly applied to clean water body monitoring, e.g., drinking water and reclaimed water, without the amending of background organic matter, and it also decreased the warning failure when challenged by a combined shock of organic matter/toxicity. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Advanced Oxygen Systems for Aircraft (Systemes d’Oxygene Avances)

    1996-04-01

    Oxygen Generating System (NAOGS), SAM-TR-80-12, Brooks AFB TX 78235, 1980. 11. Horch TC, Miller RL, Bomar JB, Tedor JB, Holden RD, Ikels KG, and...sieve oxygen generation sys- tem. Data from Horch et al (15). cabin altitude. The minimum and maximum oxygen concen- tration lines depict the...an AV-8A Aircraft; Naval Air Test Center Report No. SY-136R-81, 1981. 15. Horch TC, Miller RL, Bomar JB Jr, Tedor JB, Holden RD, Ikels KG, and

  19. Semiconductor acceleration sensor

    Ueyanagi, Katsumichi; Kobayashi, Mitsuo; Goto, Tomoaki

    1996-09-01

    This paper reports a practical semiconductor acceleration sensor especially suited for automotive air bag systems. The acceleration sensor includes four beams arranged in a swastika structure. Two piezoresistors are formed on each beam. These eight piezoresistors constitute a Wheatstone bridge. The swastika structure of the sensing elements, an upper glass plate and a lower glass plate exhibit the squeeze film effect which enhances air dumping, by which the constituent silicon is prevented from breakdown. The present acceleration sensor has the following features. The acceleration force component perpendicular to the sensing direction can be cancelled. The cross-axis sensitivity is less than 3 percent. And, the erroneous offset caused by the differences between the thermal expansion coefficients of the constituent materials can be canceled. The high aspect ratio configuration realized by plasma etching facilitates reducing the dimensions and improving the sensitivity of the acceleration sensor. The present acceleration sensor is 3.9 mm by 3.9 mm in area and 1.2 mm in thickness. The present acceleration sensor can measure from -50 to +50 G with sensitivity of 0.275 mV/G and with non-linearity of less than 1 percent. The acceleration sensor withstands shock of 3000 G.

  20. Polymer Electrolyte-Based Ambient Temperature Oxygen Microsensors for Environmental Monitoring

    Hunter, Gary W.; Xu, Jennifer C.; Liu, Chung-Chiun

    2011-01-01

    An ambient temperature oxygen microsensor, based on a Nafion polymer electrolyte, has been developed and was microfabricated using thin-film technologies. A challenge in the operation of Nafion-based sensor systems is that the conductivity of Nafion film depends on the humidity in the film. Nafion film loses conductivity when the moisture content in the film is too low, which can affect sensor operation. The advancement here is the identification of a method to retain the operation of the Nafion films in lower humidity environments. Certain salts can hold water molecules in the Nafion film structure at room temperature. By mixing salts with the Nafion solution, water molecules can be homogeneously distributed in the Nafion film increasing the film s hydration to prevent Nafion film from being dried out in low-humidity environment. The presence of organics provides extra sites in the Nafion film to promote proton (H+) mobility and thus improving Nafion film conductivity and sensor performance. The fabrication of ambient temperature oxygen microsensors includes depositing basic electrodes using noble metals, and metal oxides layer on one of the electrode as a reference electrode. The use of noble metals for electrodes is due to their strong catalytic properties for oxygen reduction. A conducting polymer Nafion, doped with water-retaining components and extra sites facilitating proton movement, was used as the electrolyte material, making the design adequate for low humidity environment applications. The Nafion solution was coated on the electrodes and air-dried. The sensor operates at room temperature in potentiometric mode, which measures voltage differences between working and reference electrodes in different gases. Repeat able responses to 21-percent oxygen in nitrogen were achieved using nitrogen as a baseline gas. Detection of oxygen from 7 to 21 percent has also been demonstrated. The room-temperature oxygen micro sensor developed has extremely low power

  1. Advanced Magnetoimpedance Sensors

    Li, Bodong

    2015-02-01

    This thesis is concerned with the advanced topics of thin film magnetoimpedance (MI) sensors. The author proposes and develops novel MI sensors that target on the challenges arising from emerging applications such as flexible electronics, passive wireless sensing, etc. In the study of flexible MI sensor, the investigated sensors of NiFe/Cu/NiFe tri-layersare fabricated on three flexible substrates having different surface roughness: Kapton, standard and premiumphotopaper. Sensitivity versus substrate roughness analysis is carried out for the selection of optimal substrate material. The high magnetic sensing performance is achieved by using Kapton substrate. Stress simulation, incorporated with the theory of magnetostriction effect, reveals the material composition of Ni/Fe being as a key factor of the stress dependent MI effect for the flexible MI sensors. In the development of MI-SAW device for passive wireless magnetic field sensing, NiFe/Cu/NiFe tri-layersand interdigital transducers(IDT) are designed and fabricated on a single piece of LiNbO3substrate, providing a high degree of integration and the advantage of standard microfabrication. The double-electrodeIDT has been utilized and proven to have an optimal sensing performance in comparison to the bi-directional IDT design. The optimized high frequency performance of the thin film MI sensor results in a MI-SAW passive wireless magnetic sensor with high magnetic sensitivity comparing to the MI microwire approach. Benefiting from the high degree of integration of the MI thin film element, in the following study, two additional sensing elements are integrated to the SAW device to have a multifunctional passive wireless sensor with extended temperature and humidity sensing capabilities. Analytical models havebeen developed to eliminate the crossovers of different sensing signals through additional reference IDTs, resulting in a multifunctional passive wireless sensor with the capability of detecting all three

  2. Simultaneous Monitoring of Vascular Oxygenation and Tissue Oxygen Tension of Breast Tumors Under Hyperbaric Oxygen Exposure

    2008-04-01

    28. Alagoz, T., R. Buller, B. Anderson, K. Terrell , R...and oxygenation Ann . New Acad. Sci. 838 29–45 Chapman J D, Stobbe C C, Arnfield M R, Santus R, Lee J and McPhee M S 1991 Oxygen dependency of tumor

  3. Micro Coriolis mass flow sensor with integrated resistive pressure sensors

    Groenesteijn, Jarno; Alveringh, Dennis; Schut, Thomas; Wiegerink, Remco J.; Sparreboom, Wouter; Lötters, Joost Conrad

    2017-01-01

    We report on novel resistive pressure sensors, integrated on-chip at the inlet- and outlet-channels of a micro Coriolis mass flow sensor. The pressure sensors can be used to measure the pressure drop over the Coriolis sensor which can be used to compensate pressure-dependent behaviour that might

  4. Resistive pressure sensors integrated with a Coriolis mass flow sensor

    Alveringh, Dennis; Schut, Thomas; Wiegerink, Remco J.; Sparreboom, Wouter; Lötters, Joost Conrad

    2017-01-01

    We report on a novel resistive pressure sensor that is completely integrated with a Coriolis mass flow sensor on one chip, without the need for extra fabrication steps or different materials. Two pressure sensors are placed in-line with the Coriolis sensor without requiring any changes to the fluid

  5. Consistent sensor, relay, and link selection in wireless sensor networks

    Arroyo Valles, M.D.R.; Simonetto, A.; Leus, G.J.T.

    2017-01-01

    In wireless sensor networks, where energy is scarce, it is inefficient to have all nodes active because they consume a non-negligible amount of battery. In this paper we consider the problem of jointly selecting sensors, relays and links in a wireless sensor network where the active sensors need

  6. Urodynamic pressure sensor

    Moore, Thomas

    1991-01-01

    A transducer system was developed for measuring the closing pressure profile along the female urethra, which provides up to five sensors within the functional length of the urethra. This new development is an improvement over an earlier measurement method that has a smaller sensor area and was unable to respond to transient events. Three sensors were constructed; one of them was subjected to approximately eight hours of use in a clinical setting during which 576 data points were obtained. The complete instrument system, including the signal conditioning electronics, data acquisition unit, and the computer with its display and printer is described and illustrated.

  7. Electrocatalytic cermet sensor

    Shoemaker, Erika L.; Vogt, Michael C.

    1998-01-01

    A sensor for O.sub.2 and CO.sub.2 gases. The gas sensor includes a plurality of layers driven by a cyclic voltage to generate a unique plot characteristic of the gas in contact with the sensor. The plurality of layers includes an alumina substrate, a reference electrode source of anions, a lower electrical reference electrode of Pt coupled to the reference source of anions, a solid electrolyte containing tungsten and coupled to the lower reference electrode, a buffer layer for preventing flow of Pt ions into the solid electrolyte and an upper catalytically active Pt electrode coupled to the buffer layer.

  8. Sensors in Education

    Van Rosmalen, Peter; Schneider, Jan; Börner, Dirk

    2014-01-01

    Sensors rapidly become available both for personal as well as scientific use. A wide range of applications exists for personal use e.g. safety in and around the house, sport, fitness and health. In this workshop we will explore how sensors are (can be) used in education. We start with an introduction on sensors and their use, discuss the FP7 project METALOGUE (www.metalogue.eu), a Multi-perspective Multi-modal Dialogue system, and close with a hands-on and a discussion of the design of the Pr...

  9. Characterization of Pixel Sensors

    Oliveira, Felipe Ferraz

    2017-01-01

    It was commissioned at CERN ATLAS pixel group a fluorescence setup for characterization of pixel sensors. The idea is to measure the energies of different targets to calibrate your sensor. It was measured four matrices (80, 95, 98 and 106) of the Investigator1 sensor with different deep PW using copper, iron and titanium as target materials. The matrix 80 has a higher gain (0.065 ± 0.002) and matrix 106 has a better energy resolution (0.05 ± 0.04). The noise of the setup is around 3.6 mV .

  10. RADIOACTIVE MATERIALS SENSORS

    Mayo, Robert M.; Stephens, Daniel L.

    2009-01-01

    Providing technical means to detect, prevent, and reverse the threat of potential illicit use of radiological or nuclear materials is among the greatest challenges facing contemporary science and technology. In this short article, we provide brief description and overview of the state-of-the-art in sensor development for the detection of radioactive materials, as well as an identification of the technical needs and challenges faced by the detection community. We begin with a discussion of gamma-ray and neutron detectors and spectrometers, followed by a description of imaging sensors, active interrogation, and materials development, before closing with a brief discussion of the unique challenges posed in fielding sensor systems.

  11. Wireless passive radiation sensor

    Pfeifer, Kent B; Rumpf, Arthur N; Yelton, William G; Limmer, Steven J

    2013-12-03

    A novel measurement technique is employed using surface acoustic wave (SAW) devices, passive RF, and radiation-sensitive films to provide a wireless passive radiation sensor that requires no batteries, outside wiring, or regular maintenance. The sensor is small (<1 cm.sup.2), physically robust, and will operate unattended for decades. In addition, the sensor can be insensitive to measurement position and read distance due to a novel self-referencing technique eliminating the need to measure absolute responses that are dependent on RF transmitter location and power.

  12. Professional Android Sensor Programming

    Milette, Greg

    2012-01-01

    Learn to build human-interactive Android apps, starting with device sensors This book shows Android developers how to exploit the rich set of device sensors—locational, physical (temperature, pressure, light, acceleration, etc.), cameras, microphones, and speech recognition—in order to build fully human-interactive Android applications. Whether providing hands-free directions or checking your blood pressure, Professional Android Sensor Programming shows how to turn possibility into reality. The authors provide techniques that bridge the gap between accessing sensors and putting the

  13. Surfactant Sensors in Biotechnology; Part 1 – Electrochemical Sensors

    Milan Sak-Bosnar

    2004-01-01

    Full Text Available An overview on electrochemical surfactant sensors is given with special attention to papers published since 1993. The importance of surfactants in modern biotechnology is stressed out. Electrochemical sensors are usually divided according to the measured physical quantity to potentiometric, amperometric, conductometric and impedimetric surfactant sensors. The last ones are very few. Potentiometric surfactant sensors are the most numerous due to their simplicity and versatility. They can be used either as end-point titration sensors or as direct EMF measurement sensors, in batch or flow-through mode. Some amperometric surfactant sensors are true biosensors that use microorganisms or living cells.

  14. Oxygen dependency of porfiromycin cytotoxicity

    Marshall, R.S.; Rauth, A.M.

    1987-01-01

    The authors determined the oxygen dependency of toxicity for the bioreductive alkylating agents mitomycin C (MMC) and porfiromycin (PM) to investigate whether the toxicities of these agents increase in the range of oxygen tensions over which cells become increasingly radioresistant. In the present work the oxygen dependency of PM in CHO cells was determined by assaying survival as a function of time of exposure to 1.0 μg/ml PM under various known levels of oxygen. While PM demonstrated preferential hypoxic cell toxicity, aerobic cell survival was reduced ten-fold after five hours of exposure. Conversely, PM toxicity after a five hour hypoxic exposure to <0.001% oxygen appeared to be greater than that observed for similar MMC exposures, suggesting that PM may be more selective than MMC in killing hypoxic rather than aerobic cells. The authors are currently investigating this preferential toxicity in two human cell lines, one of which is resistant to these agents. At present, these observations suggest that PM may be more effective than MMC at destroying tumour cells in regions of intermediate and low oxygen tensions which may survive radiotherapy, though the range of oxygen tensions which mediate toxicity is similar for both agents

  15. Oxygen treatment of cluster headache

    Petersen, Anja S; Barloese, Mads C J; Jensen, Rigmor H

    2014-01-01

    PURPOSE: Our aim was to review the existing literature to document oxygen's therapeutic effect on cluster headache. METHOD: A PubMed search resulted in 28 hits, and from these and their references we found in total 11 relevant studies. We included six studies that investigated the efficacy......, but not a prophylactic effect. Despite the fact that only a few high-quality RCT studies are available, oxygen treatment is close to an ideal treatment because it is effective and safe. However, sufferers of cluster headache do not always have access to oxygen because of logistic and financial concerns....

  16. Oxygen diffusion in cuprate superconductors

    Routbort, J.L.; Rothman, S.J.

    1995-01-01

    Superconducting properties of the cuprate superconductors depend on the oxygen content of the material; the diffusion of oxygen is thus an important process in the fabrication and application of these materials. This article reviews studies of the diffusion of oxygen in La 2-x Sr x CuO 4 , YBa 2 Cu 3 O 7- δ, YBa 2 Cu 4 O 8 , and the Bi 2 Sr 2 Ca n-1 Cu n O 2+4 (n = 1, and 2) superconductors, and attempt to elucidate the atomic mechanisms responsible

  17. Oxygen permeation modelling of perovskites

    van Hassel, Bart A.; van Hassel, B.A.; Kawada, Tatsuya; Sakai, Natsuko; Yokokawa, Harumi; Dokiya, Masayuki; Bouwmeester, Henricus J.M.

    1993-01-01

    A point defect model was used to describe the oxygen nonstoichiometry of the perovskites La0.75Sr0.25CrO3, La0.9Sr0.1FeO3, La0.9Sr0.1CoO3 and La0.8Sr0.2MnO3 as a function of the oxygen partial pressure. Form the oxygen vacancy concentration predicte by the point defect model, the ionic conductivity

  18. OLED-polypropylene bio-CD sensor

    Vengasandra, Srikanth; Cai, Yuankun; Grewell, David; Shinar, Joseph; Shinar, Ruth

    2008-08-01

    With the goal of developing microfluidic platforms for sensing applications, flash-free micro patterns were embossed in polypropylene surfaces with ultrasonic heating for a biosensing lab-on-CD application. The embossed features were designed to act as reservoirs, valves, and reaction chambers to allow, in combination with a compact sensing platform, the monitoring of analyte levels using a standard PC-CD player. To generate the compact sensor, as an example, we chose the photoluminescence (PL)-based detection of lactate and glucose using an OLED-based sensing platform. Once embossed, the surface energy of the plastic substrate was chemically modified to make it hydrophilic. Reagents, placed in separate reservoirs, were directed through burst valves towards a reaction chamber via CD rotation. Lactate or glucose were monitored by measuring the effect of the related dissolved oxygen level on the PL decay time of an oxygen-sensitive dye, following analyte oxidation catalyzed by a suitable specific oxidase enzyme. The results demonstrate the potential of integrating OLEDs as excitation sources in PL-based sensors with microfluidic CD-based platforms, including for simultaneous multiple analyses.

  19. Chemical Vapor Identification by Plasma Treated Thick Film Tin Oxide Gas Sensor Array and Pattern Recognition

    J. K. Srivastava

    2011-02-01

    Full Text Available Present study deals the class recognition potential of a four element plasma treated thick film tin oxide gas sensor array exposed with volatile organic compounds (VOCs. Methanol, Ethanol and Acetone are selected as target VOCs and exposed on sensor array at different concentration in range from 100-1000 ppm. Sensor array consist of four tin oxide sensors doped with 1-4 % PbO concentrations were fabricated by thick film technology and then treated with oxygen plasma for 5-10 minute durations. Sensor signal is analyzed by principal component analysis (PCA for visual classification of VOCs. Further output of PCA is used as input for classification of VOCs by four pattern classification techniques as: linear discriminant analysis (LDA, k-nearest neighbor (KNN, back propagation neural network (BPNN and support vector machine (SVM. All the four classifier results 100 % correct classification rate of VOCs by response analysis of sensor array treated with plasma for 5 minute.

  20. Nitric Oxide Release for Improving Performance of Implantable Chemical Sensors - A Review.

    Cha, Kyoung Ha; Wang, Xuewei; Meyerhoff, Mark E

    2017-12-01

    Over the last three decades, there has been extensive interest in developing in vivo chemical sensors that can provide real-time measurements of blood gases (oxygen, carbon dioxide, and pH), glucose/lactate, and potentially other critical care analytes in the blood of hospitalized patients. However, clot formation with intravascular sensors and foreign body response toward sensors implanted subcutaneously can cause inaccurate analytical results. Further, the risk of bacterial infection from any sensor implanted in the human body is another major concern. To solve these issues, the release of an endogenous gas molecule, nitric oxide (NO), from the surface of such sensors has been investigated owing to NO's ability to inhibit platelet activation/adhesion, foreign body response and bacterial growth. This paper summarizes the importance of NO's therapeutic potential for this application and reviews the publications to date that report on the analytical performance of NO release sensors in laboratory testing and/or during in vivo testing.

  1. Magnetic Nanocomposite Cilia Tactile Sensor

    Alfadhel, Ahmed

    2015-10-21

    A multifunctional biomimetic nanocomposite tactile sensor is developed that can detect shear and vertical forces, feel texture, and measure flow with extremely low power consumption. The sensor\\'s high performance is maintained within a wide operating range that can be easily adjusted. The concept works on rigid and flexible substrates and the sensors can be used in air or water without any modifications.

  2. Downhole pressure sensor

    Berdahl, C. M.

    1980-01-01

    Sensor remains accurate in spite of varying temperatures. Very accurate, sensitive, and stable downhole pressure measurements are needed for vaiety of reservoir engineering applications, such as deep petroleum reservoirs, especially gas reservoirs, and in areas of high geothermal gradient.

  3. Reconfigurable Sensor Monitoring System

    Alhorn, Dean C. (Inventor); Dutton, Kenneth R. (Inventor); Howard, David E. (Inventor); Smith, Dennis A. (Inventor)

    2017-01-01

    A reconfigurable sensor monitoring system includes software tunable filters, each of which is programmable to condition one type of analog signal. A processor coupled to the software tunable filters receives each type of analog signal so-conditioned.

  4. Sensor for metal detection

    Kodzius, Rimantas; Zhao, Guoqing

    2014-01-01

    fluid, peritoneal fluid, pleural fluid, pericardial fluid, joint fluid, and amniotic fluid, water sample, food sample, air sample, and soil sample (all claimed). ADVANTAGE - The sensor for use with the portable analytical instrument is configured

  5. Magnetic Nanocomposite Cilia Sensors

    Alfadhel, Ahmed

    2016-01-01

    Recent progress in the development of artificial skin concepts is a result of the increased demand for providing environment perception such as touch and flow sensing to robots, prosthetics and surgical tools. Tactile sensors are the essential

  6. Parachute Cord Tension Sensor

    National Aeronautics and Space Administration — To design and fabricate a light weight (few oz), very small (~2 inch length) parachute cord tension sensor demonstrator device.A major challenge for the CPAS (The...

  7. Modular sensor network node

    Davis, Jesse Harper Zehring [Berkeley, CA; Stark, Jr., Douglas Paul; Kershaw, Christopher Patrick [Hayward, CA; Kyker, Ronald Dean [Livermore, CA

    2008-06-10

    A distributed wireless sensor network node is disclosed. The wireless sensor network node includes a plurality of sensor modules coupled to a system bus and configured to sense a parameter. The parameter may be an object, an event or any other parameter. The node collects data representative of the parameter. The node also includes a communication module coupled to the system bus and configured to allow the node to communicate with other nodes. The node also includes a processing module coupled to the system bus and adapted to receive the data from the sensor module and operable to analyze the data. The node also includes a power module connected to the system bus and operable to generate a regulated voltage.

  8. Uncooled tunneling infrared sensor

    Kenny, Thomas W. (Inventor); Kaiser, William J. (Inventor); Podosek, Judith A. (Inventor); Vote, Erika C. (Inventor); Muller, Richard E. (Inventor); Maker, Paul D. (Inventor)

    1995-01-01

    An uncooled infrared tunneling sensor in which the only moving part is a diaphragm which is deflected into contact with a micromachined silicon tip electrode prepared by a novel lithographic process. Similarly prepared deflection electrodes employ electrostatic force to control the deflection of a silicon nitride, flat diaphragm membrane. The diaphragm exhibits a high resonant frequency which reduces the sensor's sensitivity to vibration. A high bandwidth feedback circuit controls the tunneling current by adjusting the deflection voltage to maintain a constant deflection of the membrane. The resulting infrared sensor can be miniaturized to pixel dimensions smaller than 100 .mu.m. An alternative embodiment is implemented using a corrugated membrane to permit large deflection without complicated clamping and high deflection voltages. The alternative embodiment also employs a pinhole aperture in a membrane to accommodate environmental temperature variation and a sealed chamber to eliminate environmental contamination of the tunneling electrodes and undesireable accoustic coupling to the sensor.

  9. Graphene Chemical Sensor Project

    National Aeronautics and Space Administration — Develop graphene based miniaturized chemical sensors that will be able to detect gaseous and volatile molecules with high sensitivity, good reproducibility and wide...

  10. Graphene Chemical Sensor

    National Aeronautics and Space Administration — Develop graphene based miniaturized chemical sensors that will be able to detect gaseous and volatile molecules with high sensitivity, good reproducibility and wide...

  11. Wearable Optical Sensors

    Ballard, Zachary S.; Ozcan, Aydogan

    2017-01-01

    The market for wearable sensors is predicted to grow to $5.5 billion by 2025, impacting global health in unprecedented ways. Optics and photonics will play a key role in the future of these wearable technologies, enabling highly sensitive

  12. Microsoft Kinect Sensor Evaluation

    Billie, Glennoah

    2011-01-01

    My summer project evaluates the Kinect game sensor input/output and its suitability to perform as part of a human interface for a spacecraft application. The primary objective is to evaluate, understand, and communicate the Kinect system's ability to sense and track fine (human) position and motion. The project will analyze the performance characteristics and capabilities of this game system hardware and its applicability for gross and fine motion tracking. The software development kit for the Kinect was also investigated and some experimentation has begun to understand its development environment. To better understand the software development of the Kinect game sensor, research in hacking communities has brought a better understanding of the potential for a wide range of personal computer (PC) application development. The project also entails the disassembly of the Kinect game sensor. This analysis would involve disassembling a sensor, photographing it, and identifying components and describing its operation.

  13. Magnetic Resonance Sensors

    Robert H. Morris

    2014-11-01

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

  14. GAINT magnetoimpedance sensors

    Hauser, H.; Kraus, Luděk; Ripka, P.

    xx, - (2001), s. 28-32 ISSN 1094-6969 Institutional research plan: CEZ:AV0Z1010914 Keywords : wireless sensor * distant measurement of magnetic fields Subject RIV: BM - Solid Matter Physics ; Magnetism

  15. Thermal microphotonic sensor and sensor array

    Watts, Michael R [Albuquerque, NM; Shaw, Michael J [Tijeras, NM; Nielson, Gregory N [Albuquerque, NM; Lentine, Anthony L [Albuquerque, NM

    2010-02-23

    A thermal microphotonic sensor is disclosed for detecting infrared radiation using heat generated by the infrared radiation to shift the resonant frequency of an optical resonator (e.g. a ring resonator) to which the heat is coupled. The shift in the resonant frequency can be determined from light in an optical waveguide which is evanescently coupled to the optical resonator. An infrared absorber can be provided on the optical waveguide either as a coating or as a plate to aid in absorption of the infrared radiation. In some cases, a vertical resonant cavity can be formed about the infrared absorber to further increase the absorption of the infrared radiation. The sensor can be formed as a single device, or as an array for imaging the infrared radiation.

  16. Observer-based Coal Mill Control using Oxygen Measurements

    Andersen, Palle; Bendtsen, Jan Dimon; S., Tom

    2006-01-01

    This paper proposes a novel approach to coal flow estimation in pulverized coal mills, which utilizes measurements of oxygen content in the flue gas. Pulverized coal mills are typically not equipped with sensors that detect the amount of coal injected into the furnace. This makes control...... of the coal flow difficult, causing stability problems and limits the plant's load following capabilities. To alleviate this problem without having to rely on expensive flow measurement equipment, a novel observer-based approach is investigated. A Kalman filter based on measurements of combustion air flow led...... into the furnace and oxygen concentration in the flue gas is designed to estimate the actual coal flow injected into the furnace. With this estimate, it becomes possible to close an inner loop around the coal mill itself, thus giving a better disturbance rejection capability. The approach is validated against...

  17. Organic magnetic field sensor

    McCamey, Dane; Boehme, Christoph

    2017-01-24

    An organic, spin-dependent magnetic field sensor (10) includes an active stack (12) having an organic material with a spin-dependence. The sensor (10) also includes a back electrical contact (14) electrically coupled to a back of the active stack (12) and a front electrical contact (16) electrically coupled to a front of the active stack (12). A magnetic field generator (18) is oriented so as to provide an oscillating magnetic field which penetrates the active stack (12).

  18. Novel PET sensors

    Cooper, C.R.

    2001-03-01

    This thesis describes the design, synthesis and evaluation of novel molecular sensors that utilize the phenomena of Photoinduced Electron Transfer (PET). PET design can be incorporated into molecules to allow them to selectively bind certain guest molecules. PET works by the modulation of electron potentials within a molecule. Binding events between a host and guest can, if designed suitably, change these potentials enough to cause a transfer of electronic charge within the molecular sensor. This event can be accurately and sensitively monitored by the use of ultra violet or fluorescence spectroscopy. A sensor molecule can be constructed by matching the guest to a suitable receptor site and incorporating this into a molecule containing a fluorophore with the correct electron potential characteristics. By using existing synthetic routes as well as exploiting new pathways these sensor molecules C n be constructed to contain a fluorophore separated from a guest receptor(s) by suitable spacers units. When put together these facets go to creating molecules that by design are sensitive and selective for certain guest molecules or functional groups. This methodology allows the synthetic chemist to rationally design and synthesise PET sensors, tailored to the needs of the guest. In this thesis the synthesis and evaluation of a novel PET sensors for D-glucosamine, disaccharides and fluoride is presented. It is believed that the novel sensors using the PET phenomenon presented in this thesis are a worthwhile extension of previous works undertaken by other groups around the world and shows new pathways to increasingly complex and sophisticated sensor molecular design. (author)

  19. Wireless radiation sensor

    Lamberti, Vincent E.; Howell, Jr, Layton N.; Mee, David K.; Kress, Reid L.

    2016-08-09

    Disclosed is a sensor for detecting radiation. The sensor includes a ferromagnetic metal and a radiation sensitive material coupled to the ferromagnetic metal. The radiation sensitive material is operable to change a tensile stress of the ferromagnetic metal upon exposure to radiation. The radiation is detected based on changes in the magnetic switching characteristics of the ferromagnetic metal caused by the changes in the tensile stress.

  20. Application of commercial sensor manufacturing methods for NOx/NH3 mixed potential sensors for emissions control

    Brosha, Eric L [Los Alamos National Laboratory; Mukundan, Rangachary [Los Alamos National Laboratory; Nelson, Mark A [Los Alamos National Laboratory; Sekhar, Praveen [Los Alamos National Laboratory; Williamson, Todd [Los Alamos National Laboratory; Garzon, Fernando H [Los Alamos National Laboratory

    2009-01-01

    The purpose of this research effort is to develop a low cost on-board Nitrogen Oxide (NO{sub x})/Ammonia (NH{sub 3}) sensor that can not only be used for emissions control but has the potential to improve efficiency through better monitoring of the combustion process and feedback control in both vehicle and stationary systems. Over the past decade, Los AJamos National Laboratory (LANL) has developed a unique class of electrochemical gas sensors for the detection of carbon monoxide, hydrocarbons, hydrogen and nitrogen oxides. These sensors are based on the mixed-potential phenomenon and are a modification of the existing automotive lambda (oxygen) sensor and have the potential to meet the stringent sensitivity, selectivity and stability requirements of an on-board emissions/engine control sensor system. The current state of the art LANL technology is based on the stabilization of the electrochemical interfaces and relies on an externally heated, hand-made, tape cast device. We are now poised to apply our patented sensing principles in a mass production sensor platform that is more suitable for real world engine-out testing such as on dynamometers for vehicle applications and for exhaust-out testing in heavy boilers/SCR systems in power plants. In this present work, our goal is to advance towards commercialization of this technology by packaging the unique LANL sensor design in a standard automotive sensor-type platform. This work is being performed with the help of a leading US technical ceramics firm, utilizing commercial manufacturing techniques. Initial tape cast platforms with screen printed metal oxide and Pt sensor electrodes have shown promising results but also clearly show the need for us to optimize the electrode and electrolyte compositions/morphologies and interfaces of these devices in order to demonstrate a sensitive, selective, and stable NO{sub x} sensor. Our previous methods and routes to preparing stable and reproducible mixed potential sensors